3I/ATLAS Comet Will Swing by Sol

tahanson43206 · 2025-07-05 12:13:02

This topic is set up for NewMars members who might wish to keep track of the progress of an interstellar object that is approaching Sol in 2025.

The object is forecast to pass between the orbits of Earth and Mars, at a velocity on the order of 60 km/s.

I'm interested in seeing discussion of how humans might place a probe on this object, and assume that the only feasible way would be to use a Solar grazing trajectory to gain dV and to make the orbital plane changes needed. This would be an impressive feat of celestial navigation.

The hardware may not be available in the time frame required, but the Parker Solar probe shows what would be needed for a close flyby of the Sun.

Gemini reminded me that a flight to graze the Sun would involve reducing velocity of the Earth (about 30 km/s) in order to drop toward the Sun, so the navigation would start with that. Gravity assists by Venus or Mercury might help to gain dV, but the needed plane change would have to come from the Sun.

Per Google:

The comet approaching our solar system from outer space has been officially designated as
3I/ATLAS. It is also known by the non-periodic comet designation C/2025 N1 (ATLAS). This is an interstellar comet, meaning it originated from another star system.
Key details about 3I/ATLAS:
Discovery: Discovered on July 1, 2025, by the NASA-funded ATLAS telescope in Chile.
Origin: Interstellar space.
Trajectory: Hyperbolic orbit, indicating it's passing through our solar system and will continue its journey into interstellar space.
Closest approach to the Sun: Around October 30, 2025, just inside the orbit of Mars.
Closest approach to Earth: It will not come closer than 1.6 astronomical units (about 150 million miles or 240 million kilometers), posing no threat to Earth.
Visibility: Should be visible to ground-based telescopes through September 2025, then again in early December 2025 after it passes the Sun.
Designations: Officially designated as 3I/ATLAS and C/2025 N1 (ATLAS).
Other details: It is the third known interstellar object to be discovered, following 'Oumuamua and 2I/Borisov. Its size and physical properties are still being investigated, but it's estimated to be potentially up to 20 kilometers wide.

(th)

tahanson43206 · 2025-07-05 12:16:58

This post is reserved for an index to posts by NewMars members...

I'm hoping we might see a robust flight plan for an intercept and probe placement. A flyby is possible but it too would be challenging.

The rudiments of an intercept flight plan should be available to those without access to sophisticated computer codes such as GMAT.

A simple ellipse would be of interest, because it would show the ballpart feasibility of an intercept mission.

Index:

(th)

tahanson43206 · 2025-07-07 15:36:18

Nice to see some interest in Atlas!

https://www.msn.com/en-us/news/technolo … 105fc&ei=9

This turns out to be an ESA initiative that was already in place. The new catch-it probe will loiter at Solar S2 and wait for an interesting object. It won't be ready for the current ATLAS object, but no doubt there will be more visitors from outside the Solar System.

The Comet Interceptor was adopted by ESA in June 2022 and is currently in development, having passed its Critical Design Review in December 2024.
The mission is scheduled to launch in 2029 as a co-passenger with the ARIEL spacecraft, after which it will wait at the Sun–Earth L2 point to intercept a pristine comet or interstellar object.

(th)

tahanson43206 · 2025-07-08 08:49:05

This post set out to try to learn what options might exist for intercept of fast moving objects that pass through the Solar System.

Gemini came up with Starshot as worth a look, and I tossed in the suggestion of mounting the Starshot accelerator on the Moon for Solar system use.

Gemini pointed out that NASA has done some interesting work with laser communications over Solar system distances.

First, thank you for taking this request, and for your thoughtful reply. I think this discussion would be of interest to the small international forum where I serve as a (Junior) Moderator. Please prepare our conversation for display in BBCode. You can use list if that would be helpful. We can display colors, blue, red and green. You may know that ESA is working on a probe that would be set at Earth/Solar L2 to loiter for interesting objects that might cross it's path. This means to me that at least one group on Earth is willing to fund expensive projects for this purpose.
Discussion: Achieving 30 km/s dV for Intercepting Solar System Objects
Introduction
This discussion is about the feasibility of achieving very high delta-V (change in velocity) for spacecraft, specifically in the realm of 30 km/s or more, with the goal of intercepting fast-moving objects within our solar system, such as comets like ATLAS. This discussion has touched upon current human capabilities, cutting-edge propulsion concepts, and the potential for future technologies. I wanted to share the summary of this exchange with the forum for your thoughts and input.
Current Delta-V Capabilities
Our current on-board propulsion systems (primarily chemical rockets) are quite limited when it comes to achieving such a high ΔV from Earth orbit. While missions to the outer solar system achieve impressive speeds, these are largely thanks to gravity assists from planets, not solely the spacecraft's own engines.
Earth Escape Velocity: Approximately 3.2 km/s from Low Earth Orbit (LEO).
Interplanetary Missions: Typically require 3.6 km/s to 8 km/s ΔV from LEO for destinations like Mars or the outer planets.
Parker Solar Probe: Achieves speeds over 192 km/s relative to the Sun, but this is overwhelmingly due to multiple gravity assists from Venus and the Sun's gravity well, not its own propulsive ΔV.
Deep Space 1 (Ion Propulsion): Demonstrated a ΔV of about 4.3 km/s over its mission, showcasing the efficiency of low-thrust, high-specific-impulse electric propulsion over long durations.
Why 30 km/s Delta-V is a Huge Challenge with Current Tech
Achieving 30 km/s ΔV with chemical rockets is practically impossible due to the "tyranny of the rocket equation." The amount of propellant required increases exponentially with desired ΔV, leading to impractically large and heavy rockets. This is why alternative propulsion methods or gravity assists are essential for high-energy missions.
Highest Accelerations Achieved (Non-Propulsion Specific)
While not directly related to spacecraft ΔV, it's interesting to note the highest accelerations human technology has achieved:
Particle Accelerators (LHC): Protons experience accelerations on the order of 1.9×108 g. (For subatomic particles).
Laser-Ion Acceleration: Achieved accelerations around 1021 g over micron distances. (Again, subatomic).
Rocket Sleds (John Stapp): A human endured 46.2 g peak acceleration in a controlled test.
Future Possibilities: Beamed Energy Propulsion and Lunar Bases
This is where the discussion gets particularly exciting, especially concerning intercepting objects like Comet ATLAS. The concept of beamed energy propulsion, specifically laser sail or laser ablation propulsion, offers a path to achieving such high ΔV.

The idea is to use a powerful, remote laser source to push a lightweight spacecraft (a "nanocraft" with a sensor package). While the Breakthrough Starshot initiative focuses on interstellar travel using Earth-based lasers, the principles are highly relevant and scalable for high-speed solar system missions.
Crucially, it was suggested that a lunar-based laser accelerator could be ideal for this application.
Advantages of a Lunar Location:
Absence of Atmosphere: Eliminates beam distortion, scattering, and absorption, allowing for much more efficient and precise laser power delivery.
Abundant Solar Energy: Especially at the lunar poles, consistent solar illumination provides ample power for demanding laser systems.
Stable Platform: The Moon offers a stable, vacuum environment for a large laser array.
Is Anyone Working on This?
While there isn't a specific, publicly funded project today for a lunar-based laser interceptor for comets, the foundational research is very much alive:
Breakthrough Starshot's Influence: This project has significantly propelled research into laser sail technology, and their work often discusses the need for future space-based laser infrastructure to overcome atmospheric limitations. The Moon is a natural fit for such a discussion.
NASA Innovative Advanced Concepts (NIAC): This program frequently funds early-stage studies into advanced propulsion, including beamed energy concepts. Research into "pellet-beam" propulsion (where lasers accelerate micro-pellets that then propel a spacecraft) and other directed energy concepts are relevant, often envisioning space-based laser sources.
Academic Research: Universities and researchers (e.g., Philip Lubin at UC Santa Barbara, Artur Davoyan at UCLA, Chris Limbach at Texas A&M) are actively working on the physics and engineering of high-power space lasers, light sails, and extreme ΔV concepts.
Foundational Technologies: Missions like NASA's Lunar Laser Communications Demonstration (LLCD) demonstrate crucial pointing, tracking, and communication capabilities necessary for future high-power laser beaming from the Moon.
Challenges Remain
Even with a lunar base, significant engineering hurdles exist for a practical system:
Immense Power Requirements: Generating and dissipating gigawatts of power on the Moon.
Beam Coherence and Focus: Maintaining a tightly focused laser beam over interplanetary distances for sustained periods.
Sail/Probe Durability: Designing materials that can withstand extreme laser intensities while remaining incredibly lightweight.
Targeting and Tracking: Precisely aiming a laser at a tiny, rapidly accelerating probe and a distant, fast-moving comet.
Miniaturization: The sensor package must be incredibly small and robust.
Conclusion
The ability to achieve 30 km/s ΔV for small probes is not yet within our grasp using current on-board propulsion. However, the concept of beamed energy propulsion, particularly from a lunar base, represents a highly promising long-term solution. The foundational research is underway, and the challenges, while significant, are being actively investigated. The fact that groups like ESA are already funding missions to loiter for interstellar objects (like their proposed L2 interceptor) indicates a clear interest in characterizing these rare visitors, underscoring the value of technologies that could enable rapid intercepts.
I look forward to your thoughts and any further insights!
Thank you for reading.

(th)

tahanson43206 · 2025-07-08 10:53:49

Gemini found that the ephemeris for 31/ATLAS is already posted in Wikipedia and TheSkyLive.com.

If anyone has a copy of Starry Night or similar astronomy program it should be possible to see the predicted path of the object.

Space.com reports that the object will pass within 30 million km of Mars on October 2nd and 3rd.

The object will have a magnitude of 11, which means it will be difficult for Mars orbiting satellites to find. let along track.

Here is a conversation about intercept or fly by with Gemini, 2025/07/08...

Starshot Technology for Solar System - Hello Again! Thank you for all your assistance with numerous requests! This is a follow up to a discussion we had recently, in which you reminded me of Starshot as a potential solution to the problem of trying to match velocity with an object like Comet ATLAS, which is expected to transit the Solar System with a velocity of about 60 km/s with respect to the Sun. We considered using the Starshot technology for a Solar System project instead of an Interstellar one. In this session, I'd like to see how far the two of us can get if we imagine a facility set up on the Moon, able to launch a lightweight probe to intercept ATLAS. The Earth is moving with respect to the Sun, and potentially we might be able to add the Earth's orbital velocity to the shot, so that the actual dV needed would be on the order of 30 km/s. It is conceivable that if navigation were sufficiently accurate, the probe might be able to approach ATLAS with such a low relative velocity that the gravity of ATLAS could capture the probe. In order to plan the flight, we would have to take the orbit of the Moon into account, as well as the orbit of the Earth. It seems logical to me that we would want to send the probe toward the object as it is exiting the Solar System, so that we are chasing object rather than meeting it. Can you think of anything else that needs to be taken into consideration?
***
This is an exciting follow-up, and using Starshot technology for a Solar System intercept presents some unique advantages and challenges. Your idea of a lunar launch facility is particularly intriguing. Let's break down the additional considerations:
Advantages of a Lunar Launch Facility for Starshot-like Probes:
Reduced Gravity Well: Launching from the Moon significantly reduces the energy required to escape a significant gravity well compared to Earth. The Moon's escape velocity is only about 2.38 km/s, versus Earth's 11.2 km/s. This means less propulsive force is needed from the laser array to get the probe up to speed.
Absence of Atmosphere: The Moon has virtually no atmosphere, eliminating atmospheric drag and the need for aerodynamic shaping or heat shields during launch. This allows for even lighter and more fragile probe designs, maximizing the delta-V from the laser propulsion. It also simplifies the laser beam's interaction with the probe, as there's no atmospheric distortion to contend with.
Stable Platform: A lunar base provides a stable platform for the massive laser array required for Starshot-like propulsion. Seismically stable regions could be chosen to ensure precise aiming.
Reduced Light Pollution/Interference: The far side of the Moon, in particular, would be an ideal location due to its radio quietness and lack of artificial light, making it perfect for both launching and receiving communications from the probe.
Additional Considerations for the Intercept Mission:
Precise Trajectory Planning and Navigation:
Comet ATLAS's Orbit: While we have an approximate velocity, cometary orbits can be highly eccentric and perturbed. Continuous, highly accurate tracking of ATLAS will be paramount. Any uncertainty in its future position and velocity will translate into significant targeting errors for a high-speed intercept.
Earth-Moon System Dynamics: You correctly identified the need to account for the Moon's orbit around the Earth, and the Earth-Moon system's orbit around the Sun. This introduces a complex multi-body problem. The timing of the launch from the Moon relative to the Earth's and Moon's positions will be critical to efficiently adding the Earth's orbital velocity to the probe's trajectory.
Gravity Assists (if applicable): While the primary propulsion is the laser array, could small gravity assists from the Earth or Moon (or even other planets if the trajectory allows) be used to fine-tune the trajectory or further augment velocity? This would require incredibly precise timing.
Course Corrections (Mid-Course and Terminal): Even with precise initial targeting, minor deviations will occur. The probe will need some form of onboard propulsion (perhaps miniature ion thrusters or even a secondary, much smaller laser sail with a lower-power onboard laser) for mid-course corrections. For terminal guidance and potential capture, these corrections become even more critical and require rapid, highly accurate adjustments.
Probe Design for High-Speed Intercept/Capture:
Durability against Dust and Debris: Even within the Solar System, high-velocity intercepts carry risks of impact from micrometeoroids and cometary dust. The probe will need a robust, lightweight shielding solution, similar to what's considered for interstellar Starshot.
Miniaturization: The core concept of Starshot is ultra-light probes. Every gram matters. The scientific instruments, communication systems, navigation sensors, and any onboard propulsion must be incredibly miniaturized and efficient.
Power Source: For a long-duration cruise and potential capture, the probe will need a reliable power source. Solar panels might be an option closer to the Sun, but for the outer Solar System, radioisotope thermoelectric generators (RTGs) or advanced atomic batteries might be necessary.
Data Transmission: Beaming back data from the outer Solar System at high velocity is a challenge. The probe will need a high-gain antenna and powerful laser communication system, likely utilizing the large laser array on the Moon as the receiver. The data rate and amount of data that can be transmitted will be limited.
Capture Mechanism at ATLAS:
Relative Velocity Reduction: This is the most challenging aspect. Even with the Earth's orbital velocity, a 30 km/s relative velocity is still extremely high for capture. The concept of "gravity capture" usually implies a much lower relative velocity, allowing the object's weak gravitational field to pull the probe into orbit.
Aerocapture (if ATLAS has a significant coma/atmosphere): If ATLAS develops a significant coma or a very tenuous atmosphere, aerocapture could theoretically be considered to shed velocity. However, this is incredibly risky and difficult to model precisely for an unknown cometary environment. The forces would be immense, and the probe would need to be designed for extreme thermal and structural loads. It's likely not feasible for such high initial relative velocities.
Braking Propulsion: If true orbital capture around ATLAS is desired, the probe would need a powerful, high-efficiency braking system. This would almost certainly mean a substantial departure from the "pure" Starshot concept, as it implies carrying a significant amount of propellant and a propulsion system. This is where the concept of "low relative velocity for capture" might conflict with the "Starshot" ideal of no onboard propulsion.
Flyby vs. Capture: It might be more realistic to aim for an extremely close, high-speed flyby to gather data, rather than attempting capture, given the technical challenges of braking from 30 km/s with a tiny probe.
Timing and Optimal Intercept Point:
Chasing vs. Meeting: Your intuition to chase the object as it exits the Solar System makes sense for reducing the relative velocity at encounter, as your velocity would be generally aligned with the comet's. This is often referred to as a "rendezvous" trajectory, even if it's not a full orbital match. Meeting it head-on would maximize relative velocity and make capture impossible.
Launch Window: The alignment of the Moon, Earth, Sun, and ATLAS will create very specific, potentially narrow, launch windows to achieve the desired trajectory and velocity advantage.
Comet Activity: Comets become more active as they approach the Sun, releasing gas and dust. Intercepting it as it exits might mean less activity, which could be beneficial for avoiding dust impacts, but also means potentially less material to study in its active state.
Laser Array Requirements:
Power and Precision: Even for a Solar System mission, the power and pointing precision of the lunar laser array will be immense. It needs to accelerate the probe to tens of kilometers per second in a very short time.
Beam Steering: As the Moon rotates and the probe moves, the laser beam must be constantly and precisely steered to keep it focused on the light sail.
Heat Dissipation: A gigawatt-scale laser array will generate enormous amounts of heat, requiring significant cooling infrastructure on the Moon.
In summary, adapting Starshot for a Solar System intercept, particularly from the Moon, offers significant advantages in terms of launch efficiency and atmospheric considerations. However, the true challenge lies in achieving the extremely low relative velocity needed for capture around a small, fast-moving object like ATLAS, and the inherent trade-offs between the "Starshot" ideal of a passive, propelled probe and the need for active braking for capture. A high-speed flyby might be a more achievable initial goal. This is a fascinating thought experiment that pushes the boundaries of current technology!
Our friends in the traditional chemical rocket industry are the best candidates to perform a flyby mission. It seems to me a probe to perform that function could be launched from Earth with escape velocity only, and just coast up to a point in the Solar System where ATLAS will pass by. Let's consider that scenario for a moment. A graph showing the path of ATLAS produced by NASA/JPL shows that Mars will be the body closest to ATLAS as it passes by. This means that orbiting satellites at Mars could point their sensors at the object as it passes by, without any other effort needed. I notice that ATLAS actually crosses the orbit of Mars twice, but I don't know where Mars will be when those crossings occur. I wonder if there is an animated diagram showing the predicted path with respect to the planetary bodies.
You're absolutely right! For a simple flyby mission to gather data, a traditional chemical rocket launched from Earth is indeed the most practical and established approach. Relying on Starshot for a flyby would be overkill and complicate things significantly.
Your idea of just launching with escape velocity and letting it coast to an intercept point is fundamentally how many interplanetary missions are planned. It's about careful timing and calculating the trajectory to be at the right place at the right time.
Let's address your excellent points about Comet ATLAS (specifically C/2020 M3, which is the interstellar one you were referring to from our previous conversation, though there are other "ATLAS" comets too, like C/2023 A3, which was recently prominent).
Mars and Comet ATLAS (C/2020 M3):
You're correct that C/2020 M3 ATLAS passed inside the orbit of Mars. NASA's information states: "It will reach its closest point to the Sun around Oct. 30, 2025, at a distance of about 1.4 au (130 million miles, or 210 million kilometers) — just inside the orbit of Mars."
While it crosses Mars's orbit, a close encounter with Mars itself is a matter of both objects being at the same point in their respective orbits at the same time. The search results confirm that Comet C/2020 M3 (ATLAS) was closest to Earth on November 14, 2020, passing between the orbits of Mars and Earth. This happened in 2020, not 2025. It seems there's a more recent interstellar comet that the search results are picking up as "3I/ATLAS" or "C/2025 N1 (ATLAS)" which was discovered on July 1, 2025, and is expected to reach perihelion (closest point to the Sun) on October 30, 2025, inside Mars's orbit. This is likely the comet you're thinking of for a current mission.
Key Point: For any specific "Comet ATLAS," it's crucial to specify its full designation (e.g., C/2020 M3, 3I/ATLAS, C/2023 A3) as there have been multiple comets discovered by the ATLAS survey. The information you found about Mars being closest is likely referring to the current interstellar object, 3I/ATLAS (C/2025 N1).
Animated Diagrams and Orbital Visualization:
This is precisely what's needed for mission planning! Unfortunately, it's rare to find ready-made, publicly accessible animated diagrams showing a specific comet's path with respect to the planets at the exact time of close approach, especially for newly discovered objects.
However, here's how you can often find or create this kind of visualization:
JPL Horizons System: This is the gold standard for ephemeris data (positions and velocities of celestial bodies). While it's not a ready-to-go animated graphic, it allows you to generate precise positional data for any given date and time for the comet and all planets. You can then use this data in a 3D visualization program (like MATLAB, Python with Matplotlib/Pygame, or dedicated astronomy software) to create your own animated diagram.
You'd input the comet's designation (e.g., "3I/ATLAS" or "C/2025 N1 (ATLAS)") and then select the solar system barycenter as your origin to see the comet's path relative to the Sun and planets. You can then specify a time range.
Online Planetarium Software / Space Simulators:
Stellarium: A free, open-source planetarium software. You can load comet orbital elements into it and then advance time to see how the comet's position changes relative to the planets. This is excellent for visual understanding.
Space Engine: A more complex, paid space simulator that allows for highly detailed, realistic visualizations of celestial mechanics. You can often import comet data.
NASA Eyes on the Solar System: This is a fantastic free tool from JPL that provides real-time 3D models and trajectories of spacecraft, planets, and often prominent comets. They might add 3I/ATLAS as it becomes more observed and confirmed. Keep an eye on it!
Dedicated Comet Tracking Websites: Websites like Heavens-Above.com (which was in your search results) or TheSkyLive.com often provide interactive orbit diagrams where you can click and drag to view the orbit from different angles and advance the date. They may not animate, but they give a good static representation for a given date.
What a Flyby Mission Would Need (Traditional Rocket):
For a chemical rocket flyby mission, you'd be looking at a trajectory that aims for a specific "rendezvous point" in space and time where the probe and the comet arrive simultaneously.
Launch Window: This is critical. The relative positions of Earth and the comet dictate very specific (and often narrow) launch windows. You can't just launch "any time" and expect to intercept it efficiently.
Delta-V (ΔV) Budget: While you mention "escape velocity only," that's just to leave Earth's gravity. To intercept a fast-moving object like 3I/ATLAS (which is traveling at ~60 km/s relative to the Sun), you need a much higher ΔV to match its heliocentric velocity vector at the point of intercept. Simply escaping Earth and coasting means your probe would retain much of Earth's orbital velocity and direction, making a precise high-speed intercept challenging without significant further propulsion.
Hohmann Transfer (Modified): For distant intercepts, a modified Hohmann transfer might be used, but for a high-speed interstellar object, it's more about calculating an "interception ellipse" or hyperbola that crosses the comet's path.
Deep Space Maneuvers (DSM): Even with the best launch, small course correction burns would be needed along the way.
Navigation and Tracking: Extremely precise navigation is required. Any tiny error in the initial trajectory or subsequent maneuvers will result in a huge miss at the vast distances involved. Ground-based radar and optical tracking of both the probe and the comet would be essential.
Probe Design:
Science Instruments: Cameras, spectrometers, dust analyzers, magnetometers – all designed to function during a very high-speed flyby (which means very short observation times).
Power: Solar panels might work for the inner Solar System, but RTGs might be needed if the flyby is in the outer reaches or lasts a long time.
Communication: High-gain antennas for transmitting data back to Earth, likely over vast distances.
Shielding: Protection against dust and micrometeoroid impacts, especially when approaching an active comet.
Data Acquisition: Capturing meaningful data during a high-speed flyby is tough. Instruments need to have very fast response times and capture capabilities. The probe might only get a few minutes or even seconds of prime observation time.
Your idea of using existing Mars orbital assets is clever! If Mars happens to be in a favorable position, and the comet passes close enough to Mars's orbit, then existing orbiters (like MRO, Mars Express, TGO, Hope, Tianwen-1) could indeed try to point their instruments. This would require:
Precise Ephemeris: The Martian mission teams would need extremely accurate predictions of the comet's trajectory.
Pointing Capability: Can their instruments slew fast enough and point accurately enough to track the fast-moving comet?
Bandwidth: Can they downlink the gathered data efficiently?
Funding/Priority: Would this ad-hoc observation be approved and funded, given their primary missions?
It's certainly a more opportunistic approach than a dedicated intercept mission, and it could provide valuable supplemental data if the geometry is favorable.
***
Thank you for thinking about this with me. The possibility of being able to use existing Mars satellites to collect data about 31/ATLAS is intriguing. And thank you for the suggestions of how to plot the path of the object. In addition to the tools you mentioned, it occurs to me that Starry Night (a commercial astronomy package) might be able to plot the path.
***
You're absolutely right to consider Starry Night! Many commercial astronomy software packages, especially those geared towards serious amateur astronomers and educators, have the capability to import comet orbital elements (ephemeris data) and then display their paths in a 3D solar system view. This would be a fantastic way to visualize the intercept, and probably much more user-friendly than directly working with JPL Horizons data for casual exploration.
Using Starry Night (or similar software) for 3I/ATLAS:
Obtain Orbital Elements: The key is to get the most up-to-date orbital elements for 3I/ATLAS (C/2025 N1). These are often available from the Minor Planet Center (MPC), JPL Small-Body Database, or reputable comet-tracking websites. You'll look for parameters like eccentricity (e), inclination (i), perihelion distance (q), longitude of the ascending node (Ω), argument of perihelion (ω), and time of perihelion passage (T).
Good news: My search results already show these for 3I/ATLAS (C/2025 N1)! For example, TheSkyLive.com and Wikipedia provide them.
Import into Software: Starry Night (and others like Celestia, or even some free online tools) will have an option to add a "new comet" or "new minor planet" and input these orbital elements.
Animate and Observe: Once imported, you can set the software to a 3D solar system view, center on the Sun, and then advance time. You should be able to see the comet's hyperbolic path and how it interacts with the orbits of the planets. This will give you the animated diagram you're looking for, allowing you to visually determine where Mars will be when 3I/ATLAS crosses its orbit, and how close the actual approach is.
Revisiting the Mars Satellite Opportunity (3I/ATLAS - C/2025 N1 specific):
The search results provide excellent confirmation and new details on this very promising opportunity for Mars orbiters:
Closest Approach to Mars: "On October 2, it will be only 30 million km from Mars." (Astronomy Magazine) and "During its inner solar system sprint, the comet will have a close shave with Mars, passing about 0.2 a.u. (30 million km) from the Red Planet on October 3rd." (Sky & Telescope)
0.2 AU is approximately 18.6 million miles or 30 million kilometers. This is still a significant distance, but much closer than its closest approach to Earth (270 million km / 1.8 AU on Dec 19, 2025).
Visibility from Mars Orbiters: "During the comet's close approach to Mars, it may reach an apparent magnitude of 11 from the planet, which means Mars orbiters may be able to observe it." (Wikipedia, citing sources)
An apparent magnitude of 11 is quite dim, but definitely within the capability of many scientific instruments on Mars orbiters. For context, the brightest stars are magnitude 0 or 1, and the naked eye limit is about magnitude 6. So, it won't be easily visible, but with sensitive cameras, it's possible.
Mars Orbiter Capabilities:
Mars Reconnaissance Orbiter (MRO): This is a prime candidate. MRO has powerful cameras like HiRISE (High Resolution Imaging Science Experiment) which can resolve objects as small as a dinner plate on the Martian surface. While 30 million km is far, the resolution of HiRISE, coupled with the ability to track objects, might allow for some imaging of the comet's nucleus and coma, especially if it's active. MRO is also a key data relay for surface missions and has robust communication systems. Its primary mission is long past, so "opportunistic" science like this is often pursued if feasible.
Other Orbiters: Mars Odyssey, Mars Express (ESA), Tianwen-1 (China), and the UAE's Hope probe (Emirates Mars Mission) are also orbiting Mars. Each has different instrument suites (e.g., spectrometers, imagers, dust analyzers) that might be able to gather valuable data during a close-ish flyby.
Tracking Fast-Moving Objects: The challenge for these orbiters isn't just distance but the angular speed of the comet as seen from Mars. 3I/ATLAS is moving very quickly (up to 68 km/s relative to the Sun). The instruments on the orbiters would need to be able to slew and track at sufficient rates to keep the comet in their field of view and avoid severe blurring. This is a common challenge for deep-space missions observing fast-moving targets, and it requires careful planning and potentially rapid, pre-programmed slews.
Conclusion for Mars Satellite Observation:
The prospect is indeed intriguing and seems quite feasible, especially for MRO's HiRISE and other imaging instruments. The key would be:
Accurate Orbital Ephemeris: Mission teams would need the best possible position and velocity data for 3I/ATLAS.
Instrument Scheduling: This would involve a significant effort to schedule the use of the instruments on the relevant orbiters, which are usually busy with their primary missions (e.g., mapping, climate studies, relaying data for rovers).
Tracking Capabilities: The ability of the individual instruments to track a fast-moving, relatively dim object at 30 million km would need to be assessed.
Data Downlink: Ensuring there's enough bandwidth to send back any collected data.
It's a fantastic example of how unexpected astronomical events can offer unique science opportunities for existing assets in space. It would be very exciting if any of the Mars missions managed to get images or spectra of this interstellar visitor!

(th)

tahanson43206 · 2025-07-29 09:18:23

This post is intended to open for discussion an idea for a slingshot concept for intercept of fast moving objects in the Solar System.

The idea came up recently (July of 2025) in conversation between Void and Calliban.

I'm interested in the idea that I remember from the discussion, of creating a rotating baton-like accelerator to put an instrument package on an intercept course to meet 31/ATLAS as it passes through the Solar System in coming months.

The dV to be given to the probe is (apparently) between 30 km/s and 60 km/s.

If we use tether material of known strength, is it possible to accumulate velocity at the tip of the radii that approaches these numbers? It would seem to me that the tensile strength of the tether is what would limit the velocity capability of an accelerator.

(th)

tahanson43206 · 2025-07-29 10:27:37

Here is a BBCode version of Gemini (2.5 Flash) analysis of a proposal to rotate a sensor package in space.

the opening scenario was extreme, and the results are also extreme, but the outer limits study suggests that by reducing the mass of the sensor package and lengthening the radius of the tether, it might be possible to arrive at a combination that might be practical for humans to try in 2025.

Thank you for your careful analysis and presentation. I chose numbers that are on the high side for the analysis, just to see if any materials exist for those extreme conditions. It seems likely that by reducing the mass of the sensor package, and by increasing the radius of the swing arm, we might find a point at which the experiment might work. I'd like to share your analysis of the worst case scenario. Because your reply includes equations, and because our small international forum uses an elderly form of bBCode, please prepare the answer you provided in BBCode, using text representation of the equations. As a clarification, this system will operate at an altitude above the surface of the Earth where length of the tether is of lesser concern. In our next round, we might be able to find a compromise that would allow the proposal to move beyond speculation to serious consideration.
It's an excellent approach to test the limits with "worst-case" parameters first; it quickly reveals the fundamental constraints. You're right, exploring the extremes is how we define the boundaries of what's possible.
Here's the analysis of the slingshot accelerator's material requirements, formatted for BBCode, with equations presented in text. I've focused on the core material strength challenge as that was the central question.
Analysis of Slingshot Accelerator Material Requirements for High-Velocity Launch
This analysis investigates the feasibility of a rotational "slingshot" accelerator for launching an instrument package at extreme velocities, specifically focusing on the material strength required for the tether. The initial parameters chosen are intentionally on the high side to test the limits of existing materials.
Scenario Parameters:
We are examining a scenario with the following challenging parameters:
Instrument Package Mass (payload): 1 metric ton (1000 kg)
Counterweight Mass: 1 metric ton (1000 kg)
Tether Radius (half the "baton" length): 1 kilometer (1000 meters)
Target Tip Velocity: 60 kilometers per second (60,000 m/s)
The goal is to determine if any currently commercially available tether material can withstand the immense tension generated under these conditions. This system is envisioned to operate at an altitude where atmospheric drag is negligible, making the tether length less of a primary concern than its inherent strength.
Calculations for Tension and Material Stress:
To evaluate the material requirements, we first need to calculate the forces involved.
1. Angular Velocity (ω):
The angular velocity is derived from the linear tip velocity and the radius.
Equation: Angular Velocity (omega) = Tip Velocity (v) / Radius (r)
Calculation: omega = 60,000 m/s / 1,000 m = 60 radians/second
This translates to an extremely rapid rotation, approximately 9.55 revolutions per second.
2. Centripetal Force (Tension) due to Masses:
The primary source of tension on the tether is the centripetal force required to keep the payload and counterweight moving in a circle. This force is highest at the central pivot point.
Equation: Centripetal Force (F) = Mass (m) * (Angular Velocity (omega))^2 * Radius (r)
For the Payload (or Counterweight):
F_payload = 1000 kg * (60 rad/s)^2 * 1000 m
F_payload = 1000 kg * 3600 rad^2/s^2 * 1000 m
F_payload = 3,600,000,000 Newtons = 3.6 x 10^9 Newtons
Total Tension from Payload and Counterweight (at pivot):
Since both masses are at the same radius and rotational speed, the tension at the pivot due to these end masses is the sum of their individual forces.
F_total_mass_tension = 3.6 x 10^9 N (from payload) + 3.6 x 10^9 N (from counterweight)
F_total_mass_tension = 7.2 x 10^9 Newtons
3. Required Material Strength and Cross-Sectional Area (Initial Estimate):
To determine if a material can withstand this force, we compare it to the material's Ultimate Tensile Strength (UTS), which is the maximum stress (Force per Unit Area) a material can endure before breaking.
Equation: Stress (sigma) = Force (F) / Area (A)
Rearranged to find required area: Required Area (A) = Force (F) / Ultimate Tensile Strength (UTS)
Let's consider the UTS of some of the strongest known materials, both commercially available and experimental (values are approximate engineering strengths, not theoretical maximums for individual molecular structures):
Zylon (PBO fiber): ~5.8 Gigapascals (GPa), or 5.8 x 10^9 N/m^2
High-Strength Carbon Nanotube/Graphene Films (experimental/high-end): ~10-60 GPa (50 x 10^9 N/m^2 for an optimistic high-end estimate)
Using a highly optimistic, theoretical high-end material with a UTS of 50 GPa:
A_required = 7.2 x 10^9 N / (50 x 10^9 N/m^2)
A_required = 0.144 square meters
If this were a circular cable, its diameter would be approximately 42.8 centimeters (about 1.4 feet).
4. Critical Factor: The Mass of the Tether Itself
The above calculation only accounts for the payload and counterweight. However, the tether itself possesses mass, and at these extreme rotational speeds, its own centripetal acceleration contributes significantly to the tension. The tension increases linearly with distance from the tip, becoming highest at the pivot point.
Let's use a more realistic high-strength fiber like Zylon, with a UTS of 5.8 GPa and a density of approximately 1560 kg/m^3.
Required Area for just one 1-ton mass (at 1 km radius):
A_required_one_side = 3.6 x 10^9 N / (5.8 x 10^9 N/m^2)
A_required_one_side = 0.62 square meters
Diameter of one side of the tether:
This would imply a circular cable diameter of approximately 88.8 centimeters (almost 1 meter).
Mass of the Tether (for one side, 1 km length):
Volume = Area * Length = 0.62 m^2 * 1000 m = 620 cubic meters
Mass = Volume * Density = 620 m^3 * 1560 kg/m^3 = 967,200 kg (approximately 967 metric tons!)
Conclusion on Material Viability:
The critical finding is that the mass of the tether itself becomes astronomically large when attempting to achieve the required strength for the given parameters. For a tether to withstand the force from a 1-ton payload at 60 km/s at a 1 km radius, even the strongest commercially available fibers (like Zylon) would need to be almost a meter in diameter along their length.
This massive tether (nearly 1000 metric tons for just one side!) would then generate its own immense centripetal force, far exceeding the strength of the material used to construct it. This creates a self-defeating scenario where increasing the tether's cross-section to handle the forces from the payload only adds so much mass that it causes the tether to fail under its own weight and rotational stress.
Therefore, for the proposed parameters (1 metric ton payload, 1 km radius, 60 km/s tip velocity):
No, commercially available materials currently do not possess the specific strength (tensile strength-to-density ratio) necessary to withstand the tension generated in this scenario.
Even the most advanced experimental materials, like high-quality carbon nanotube or graphene films, while theoretically stronger, have not been scaled to produce defect-free, kilometer-long tethers with sufficient engineering strength to meet these demands.
Outlook:
This analysis highlights that the chosen parameters represent an extreme challenge beyond current material science capabilities. However, this does not invalidate the general concept of rotational accelerators. It strongly suggests that to make such a system feasible, a significant compromise would be needed, likely involving:

Substantially reducing the instrument package mass.
Significantly increasing the radius of the swing arm (which reduces the angular velocity needed for a given tip speed, thus reducing some forces, but vastly increases the physical scale).
We can explore such compromises in future discussions to identify a "sweet spot" where material properties might allow for a practical system.

(th)

tahanson43206 · 2025-07-29 11:18:15

In this conversation, I asked Gemini 2.5 Flash to look at a much reduced scenario...

We dropped the sensor package to 1 kg, and extended the radius all the way to 100 km.

It was a bit disappointing to find that the mass of the tether ended up as the limit ... As the tether length grows, the tensile strength needed to hold itself together increases to the breaking point of known materials.

First, thank you for your excellent BBCode presentation. It was accepted by our elderly forum software on the first try. I added a few embellishments to highlight particular points you made. Now let's draw in the outer boundaries of our proposal. Let's drop the sensor package to 1 kilogram. That will be challenging but may be feasible with modern electronics. We can extend the radius beyond a kilometer since the accelerator will be operating in open space well away from Earth. We can reduce the dV from 60 to 30, if we time the launch for when the Earth is providing the benefit of it's 30 km/s velocity. In that scenario the object would be well past the Solar System, so instrument package would have to catch up over a period years. I appreciate your care in designing the tether with varying diameter to handle the changes in stress due to the mass of tether itself. This reminds me of analysis of the space elevator concept, which had a similar taper. Please prepare this analysis is the same BBCode format. It worked the first time, so please don't change anything. Let's see what we get with the reduced requirements.
Okay, excellent! I'm glad the BBCode formatting worked seamlessly for your forum. That's great to hear.
Let's adjust the parameters and re-evaluate the feasibility with these significantly relaxed (though still very challenging!) requirements. This iterative process is crucial for design.
Here's the analysis with the new parameters, presented again in the same BBCode format:
Analysis of Slingshot Accelerator Material Requirements: Revised Parameters
Building upon our previous "worst-case" scenario, we are now investigating a more constrained, but potentially more feasible, set of parameters for the rotational slingshot accelerator. The goal remains to determine if currently available or near-term materials can withstand the required tension for launching an instrument package at interstellar velocities.
This system is envisioned to operate in open space, well away from significant atmospheric drag or gravitational influences that would complicate the tether's operation.
Revised Scenario Parameters:
We are now examining a scenario with the following parameters:
Instrument Package Mass (payload): 1 kilogram (kg) - A significant reduction, requiring highly miniaturized electronics.
Counterweight Mass: 1 kilogram (kg) - Balancing the payload.
Target Delta-V (velocity change): 30 kilometers per second (30,000 m/s) - This velocity would be added to Earth's orbital velocity (approx. 30 km/s) if launched optimally, allowing for a "catch-up" trajectory with an interstellar object over several years.
Tether Radius (half the "baton" length): We will keep this as a variable for now to explore what radius might become feasible, starting with an assumption that it will be significantly larger than 1 km. Let's explore a radius of 100 kilometers (100,000 meters) as a starting point to see how the numbers change. This larger radius helps significantly reduce the angular velocity for the same tip speed.
Calculations for Tension and Material Stress (Revised):
1. Angular Velocity (ω):
The angular velocity is now derived from the target tip velocity (30 km/s) and the new, much larger radius (100 km).
Equation: Angular Velocity (omega) = Tip Velocity (v) / Radius (r)
Calculation: omega = 30,000 m/s / 100,000 m = 0.3 radians/second
This is a vastly slower rotation compared to the previous scenario, roughly 0.048 revolutions per second, or about 2.86 revolutions per minute. This reduction in angular velocity (omega squared term) will have a profound positive impact on the forces.
2. Centripetal Force (Tension) due to Masses:
The tension from the payload and counterweight at the pivot point is recalculated with the new parameters.
Equation: Centripetal Force (F) = Mass (m) * (Angular Velocity (omega))^2 * Radius (r)
For the Payload (or Counterweight):
F_payload = 1 kg * (0.3 rad/s)^2 * 100,000 m
F_payload = 1 kg * 0.09 rad^2/s^2 * 100,000 m
F_payload = 9,000 Newtons = 9 x 10^3 Newtons

Total Tension from Payload and Counterweight (at pivot):
F_total_mass_tension = 9,000 N (from payload) + 9,000 N (from counterweight)
F_total_mass_tension = 18,000 Newtons = 1.8 x 10^4 Newtons
This is a massive reduction in force compared to the 7.2 x 10^9 Newtons from the previous scenario!
3. Required Material Strength and Cross-Sectional Area (Initial Estimate, Ignoring Tether Mass):
Let's again use an optimistic, high-end commercial material for the tether, such as Zylon, with an Ultimate Tensile Strength (UTS) of 5.8 Gigapascals (GPa), or 5.8 x 10^9 N/m^2.
Equation: Required Area (A) = Force (F) / Ultimate Tensile Strength (UTS)
A_required = 1.8 x 10^4 N / (5.8 x 10^9 N/m^2)
A_required = 0.000003103 square meters
This translates to a circular cable diameter of:
d = 2 * sqrt(A / pi) = 2 * sqrt(0.000003103 / pi) approx 0.001986 meters
Or approximately 1.986 millimeters (mm). This is a very thin, fine cable!
4. Critical Factor: The Mass of the Tether Itself (Recalculated)
Now, we must re-evaluate the impact of the tether's own mass, which was the dominant factor in the previous analysis. For this calculation, we assume a tapered tether design, where the cross-sectional area increases towards the center (pivot point) to handle the increasing load from the distributed mass along its length. This is crucial for long tethers.
The stress at the pivot point due to the tether's own mass (for a uniform taper designed to maintain constant stress or a well-optimized profile) is directly related to the material's density, angular velocity, and the length of the tether. More accurately, the maximum possible length of a uniform-stress tether (often called its "characteristic length" or "breaking length") made of a given material, when rotating, is limited by its specific strength (UTS/density).
Let's estimate the mass of the tether. If one side of the tether is 100 km long, with an average diameter, the total mass still becomes significant.
However, for a uniform stress cable (idealized, tapered for maximum efficiency), the tension at any point is just the load from the mass beyond it, plus the integrated mass of the cable itself. The maximum tension at the center is the most critical.
A key metric for space tethers is the characteristic length (L_c) or "breaking length" for a rotating tether, which is given by:
L_c = sqrt(2 * UTS / (Density * (Angular Velocity)^2))
Let's calculate this for Zylon:
UTS = 5.8 x 10^9 N/m^2
Density = 1560 kg/m^3
Angular Velocity = 0.3 rad/s
L_c = sqrt(2 * 5.8 x 10^9 N/m^2 / (1560 kg/m^3 * (0.3 rad/s)^2))
L_c = sqrt(11.6 x 10^9 / (1560 * 0.09))
L_c = sqrt(11.6 x 10^9 / 140.4)
L_c = sqrt(82,621,082.6)
L_c approx 9,089 meters or approx 9.1 kilometers
Interpretation of Characteristic Length:
The characteristic length represents the theoretical maximum length a uniform-stress, perfectly tapered tether of that material could reach under its own rotational forces. If our desired radius (100 km) exceeds this characteristic length, it implies that the tether's own mass (even when optimally tapered) would cause it to break before reaching that length at the specified angular velocity.
Our chosen radius of 100 kilometers (100,000 meters) is significantly greater than the calculated characteristic length of Zylon (9.1 km) for this angular velocity. This means that even with an ideally tapered Zylon tether, it would break under its own rotational stress before reaching a length of 100 km at 0.3 rad/s.
Conclusion on Material Viability with Revised Parameters:
While the reduction in payload mass and desired delta-V dramatically reduces the tension from the end masses, increasing the radius to 100 km introduces a new, dominant constraint: the tether's own mass at that extreme length and angular velocity.
Zylon (and similar high-performance fibers): Even with the significantly relaxed requirements, a 100 km radius tether is still beyond the reach of materials like Zylon. The calculated characteristic length of approximately 9.1 km indicates that Zylon cannot sustain a 100 km length at an angular velocity of 0.3 rad/s (needed for 30 km/s at 100 km radius). It would break under its own distributed mass.
The "Space Elevator" Analogy: Your analogy to the space elevator is very apt. A geosynchronous space elevator would require materials with a characteristic length far exceeding that of any current material, often cited as needing UTS/density values an order of magnitude higher than carbon nanotubes. While our rotating tether is different, the fundamental challenge of self-gravitational/self-centripetal forces limiting length remains.
Moving Forward:
For this concept to become feasible with existing or near-term materials, one or both of the following must be considered:
Increase the tether's radius even further: This would continue to reduce the angular velocity for the same tip speed, which would increase the characteristic length. However, a 100 km radius is already massive; further increases pose immense practical challenges for construction and stability.
Find a material with a significantly higher specific strength (UTS/Density): We would need a material whose characteristic length for a rotating tether greatly exceeds 100 km at the required angular velocity. This points towards the need for hypothetical "super-materials" not yet available commercially, potentially even beyond the best reported experimental CNTs or graphene in bulk.
It appears that even with a 1 kg payload and a 30 km/s delta-V, a 100 km radius tether pushes beyond the current limits of material science due to the tether's own mass. The specific strength of the material is the ultimate limiting factor for long rotating tethers.

(th)

tahanson43206 · 2025-07-29 11:45:37

In this third session, I asked Gemini (2.5 Flash) to attempt to calculate the maximum dV that might be achieved using a rotating accelerator with known materials. The answer appears to be about 3 km/s, which is far short of the requirement of (about) 30 km/s to match orbit with 31/ATLAS.

Thank you (again) for this very nice addition to a series I am offering to our audience on this interesting theme. The idea of rotation is of current interest because of the success of the SpinLaunch company. While the company has had to pull back from it's ambitious plans, it has maintained a viable capability with their original test system. I'd like to enlist your support for third post in our series, which will explore what we actually ** can ** achieve with the rotating baton concept. Let's return to our original scenario of a kilometer radius for the tether, because that seems achievable with existing capabilities. I understand that a tether of 31.7 kilometers was deployed in an experiment in 2007, so a 2 kilometer long tether would appear to be within reason for a new experiment. Let us increase the payload and counterweight to 100 kg, because we know ahead of time we cannot achieve our desired velocity increment. The payload is going to have to include propulsive capability, so increased mass is required. Please apply what you've shown us previously, to this more practical scenario. In other words, given the materials we have available today, what dV can we give to our 100 kg package?
Thank you! This iterative process is exactly how engineering challenges are tackled. The success of SpinLaunch, even with their reduced scope, certainly validates the core concept of kinetic launch and the importance of materials science in pushing those boundaries. And the 2007 tether experiment confirms that deploying long tethers in space is achievable, though for different purposes.
Let's dive into this more practical scenario to determine what velocity increment we can achieve with a 1 km radius and a 100 kg payload, using existing materials.
Analysis of Slingshot Accelerator Material Requirements: Practical Limits with Existing Materials
In this third exploration, we're returning to a more "grounded" scenario, keeping the tether radius to a more manageable 1 kilometer (based on previous successful tether deployments) and increasing the payload/counterweight to 100 kg (acknowledging the need for internal propulsion and robust components). Our goal now is to determine the maximum velocity increment (Delta-V) that can be imparted to the 100 kg package, given the strength of commercially available materials.
This system is assumed to operate in the vacuum of space, eliminating atmospheric drag. The tether design will ideally be tapered to efficiently handle the increasing tension towards the center.
Scenario Parameters:
Instrument Package Mass (payload): 100 kilograms (kg)
Counterweight Mass: 100 kilograms (kg)
Tether Radius (half the "baton" length): 1 kilometer (1000 meters)
Unknown: Maximum achievable Tip Velocity (Delta-V)
Material Selection:
For this analysis, we will consider three of the strongest, commercially available high-performance fibers:
Zylon (PBO fiber):
Ultimate Tensile Strength (UTS): ~5.8 GPa (5.8 x 10^9 N/m^2)
Density (ρ): ~1560 kg/m^3
Dyneema (UHMWPE fiber, e.g., SK99):
Ultimate Tensile Strength (UTS): Up to ~4.3 GPa (4.3 x 10^9 N/m^2) (some sources cite higher for specific formulations, but 4.3 GPa is a good representative high value for strong grades)
Density (ρ): ~970 kg/m^3 (notably less dense than Zylon)
High-Strength Carbon Fiber (typical engineering values for composites):
Ultimate Tensile Strength (UTS): ~3.5-7.0 GPa (Let's use an optimistic 5.0 GPa for high-strength grades in a well-made composite).
Density (ρ): ~1750 kg/m^3 (varies, but representative for carbon fiber composites)
Methodology: Calculating the Maximum Achievable Velocity
Instead of fixing the velocity, we'll now fix the material strength and tether length, and work backward to find the maximum sustainable angular velocity, and thus the maximum tip velocity.
The critical limiting factor for long, rotating tethers, as we've discussed, is the tether's own mass. Even with optimal tapering (a uniform stress profile), the maximum length a tether can be is determined by its "characteristic length" (Lc) for rotation.
Equation: Characteristic Length (L_c) = sqrt(2 * UTS / (Density * (Angular Velocity (omega))^2))
We need to solve for omega:
omega^2 = (2 * UTS) / (Density * (L_c)^2)
omega = sqrt((2 * UTS) / (Density * (L_c)^2))
Since our tether has a radius (half-length) of 1 km (1000 m), for a full 2 km baton, the length L would be 2 km. For the characteristic length calculation, we're considering the half-length or radius that the tether needs to support. So, L_c will be set to our tether radius, r = 1000 m.
Then, the tip velocity v = omega * r.
Let's calculate the maximum achievable omega and v for each material, considering the forces from both the tether's own mass and the 100 kg end masses. The actual tension will be the sum of these. For a practical design, the tether must withstand the tension from the end mass plus the integrated tension from its own distributed mass.
The maximum tension at the pivot point (T_max) for a tapered tether with an end mass (m) is approximately:
T_max = m * omega^2 * r + (1/2) * A_max * Density * omega^2 * r^2
where A_max is the cross-sectional area at the pivot. A simpler, more direct approach for feasibility is to consider the "breaking length" for a given omega.
A more robust way to approach this is to determine the maximum angular velocity (omega) that the material can support for a given length, assuming an optimally tapered tether and a minimal payload. Then we'll check if a 100 kg payload is also feasible within that omega.
Calculation for Each Material (considering characteristic length as the primary constraint on tether length):
The concept of characteristic length (Lc) helps define the theoretical maximum length a tether of a given material can be before its own rotational forces cause it to break. Since we're trying to achieve a 1 km radius (1000 m), we need a material whose Lc is at least 1000 m at the determined angular velocity.
Let's re-arrange the characteristic length equation to solve for the maximum angular velocity (ωmax) that a 1000m tether could theoretically sustain due to its own mass:
omega_max = sqrt((2 * UTS) / (Density * (1000 m)^2))
And then, v_max = omega_max * 1000 m.
1. Zylon (PBO Fiber):
UTS = 5.8 x 10^9 N/m^2
Density = 1560 kg/m^3
r = 1000 m
omega_max = sqrt((2 * 5.8 x 10^9) / (1560 * (1000)^2))
omega_max = sqrt(11.6 x 10^9 / (1560 * 10^6))
omega_max = sqrt(11.6 x 10^9 / 1.56 x 10^9)
omega_max = sqrt(7.43589)
omega_max approx 2.727 rad/s
Maximum Tip Velocity for Zylon (due to tether's own mass constraint):
v_max_Zylon = omega_max * r = 2.727 rad/s * 1000 m = 2727 m/s
v_max_Zylon approx 2.73 km/s
Now, let's check the tension at the pivot for this velocity with the 100 kg payload:
F_payload_at_2.73km/s = 100 kg * (2.727 rad/s)^2 * 1000 m
F_payload = 100 * 7.436 * 1000 = 743,600 Newtons
Required cross-sectional area for 100 kg payload using Zylon:
A_payload_Zylon = 743,600 N / (5.8 x 10^9 N/m^2) = 0.000128 m^2 (approx. 128 mm^2)
This is a very small area for the payload force. The dominant factor is still the tether's own mass. The 2.73 km/s velocity is the absolute maximum even if the end masses were zero, due to the 1 km length constraint on Zylon. Adding the 100 kg payload means the tether would need to be thicker at the end, but the central stress is still limited by the characteristic length.
2. Dyneema (UHMWPE Fiber):
UTS = 4.3 x 10^9 N/m^2
Density = 970 kg/m^3
r = 1000 m
omega_max = sqrt((2 * 4.3 x 10^9) / (970 * (1000)^2))
omega_max = sqrt(8.6 x 10^9 / (970 * 10^6))
omega_max = sqrt(8.6 x 10^9 / 0.97 x 10^9)
omega_max = sqrt(8.8659)
omega_max approx 2.978 rad/s
Maximum Tip Velocity for Dyneema:
v_max_Dyneema = omega_max * r = 2.978 rad/s * 1000 m = 2978 m/s
v_max_Dyneema approx 2.98 km/s
Dyneema, due to its significantly lower density (higher specific strength), performs better than Zylon despite a slightly lower UTS.
3. High-Strength Carbon Fiber (Optimistic Values):
UTS = 5.0 x 10^9 N/m^2
Density = 1750 kg/m^3
r = 1000 m
omega_max = sqrt((2 * 5.0 x 10^9) / (1750 * (1000)^2))
omega_max = sqrt(10.0 x 10^9 / (1750 * 10^6))
omega_max = sqrt(10.0 x 10^9 / 1.75 x 10^9)
omega_max = sqrt(5.714)
omega_max approx 2.390 rad/s
Maximum Tip Velocity for Carbon Fiber:
v_max_CarbonFiber = omega_max * r = 2.390 rad/s * 1000 m = 2390 m/s
v_max_CarbonFiber approx 2.39 km/s
Carbon fiber, despite good UTS, is denser, resulting in a lower maximum velocity for this tether length.
Summary of Achievable Delta-V (for a 1 km radius tether with 100 kg payload):
Based on the characteristic length (which effectively accounts for the tether's own mass), the maximum achievable Delta-V for a 1 km radius baton with current high-strength materials is in the range of 2.4 to 3.0 kilometers per second.
Zylon: Approximately 2.73 km/s
Dyneema: Approximately 2.98 km/s
High-Strength Carbon Fiber: Approximately 2.39 km/s
Implications for Intercepting Interstellar Objects:
While a Delta-V of 2.4-3.0 km/s is a significant achievement for a non-propulsive primary launch, it falls well short of the 30 km/s (or 60 km/s) needed for direct high-speed intercepts or even adding to Earth's velocity to reach interstellar space rapidly.
This means that the 100 kg payload would definitely require its own substantial propulsive capability (e.g., chemical rockets, ion thrusters, or even a smaller, secondary kinetic stage) to achieve the necessary additional velocity (Delta-V) to:
Escape the Solar System: The Earth's orbital velocity is ~30 km/s. To escape the Sun's gravity from Earth's orbit requires reaching ~42 km/s relative to the Sun (escape velocity). If the slingshot provides ~3 km/s, the payload would still need an additional ~9 km/s of Delta-V from its own engines after launch to escape the Solar System, assuming an optimal launch direction (tangential to Earth's orbit).
Intercept an Interstellar Object: Catching up with an object moving at high interstellar velocities would then require even more Delta-V on top of Solar System escape, depending on the desired rendezvous time and trajectory.
Conclusion of Practicality:
The 1 km radius rotating baton, even with a 100 kg payload and using the best available materials, can provide a meaningful velocity boost of a few kilometers per second. This is a valuable contribution, potentially saving a large amount of onboard fuel, but it is not a standalone solution for directly launching a probe to intercept an interstellar object at high velocities like 3I/ATLAS.
The primary limitation remains the specific strength of the tether material. To achieve the tens of kilometers per second needed for interstellar intercepts without significant onboard propulsion, we would either need:
Vastly stronger materials (orders of magnitude beyond current capabilities).
Significantly larger tether radii (hundreds or thousands of kilometers), which introduces monumental engineering challenges in construction, stability, and control, even in space.
Nevertheless, this analysis confirms that the concept, with careful engineering and within these more realistic velocity bounds, is indeed achievable from a material strength perspective for its primary acceleration phase. The "trick" then shifts to the secondary propulsion system onboard the probe to achieve the final, very high velocity.

(th)

tahanson43206 · 2025-07-29 11:56:57

I offered Gemini an opportunity to see what it could do on it's own without my prompting.

Thank you for your significant contribution to what I hope will be regarded as a valuable addition to the knowledge we are trying to build up in our forum. While everything we do together is subject to intense scrutiny, and I will be responsible for making any corrections that might be needed. I am reasonably confident your work will stand up well. The practical conclusion that a dV of 3 km/s might be possible with a rotating system means that is is unlikely to be regarded as a candidate to solve the 30 km/s dV requirement. Before we leave this topic, I'd like to offer you an opportunity to unleash your powers to see if you can think of a way to place an instrument package on 31/ATLAS. We humans (or at least the subset of our group) have run out of ideas.
That's a very generous assessment, and I appreciate your confidence in the analysis. The goal is always to provide accurate and useful information that can withstand scrutiny. You're right, a 3 km/s Delta-V from a kinetic launch, while impressive in its own right, is indeed a small fraction of what's needed for a direct, rapid intercept of 3I/ATLAS.
This leads us to a fascinating challenge: Given the incredible speed of 3I/ATLAS and the limited time, how could we realistically place an instrument package on it, or at least achieve a very close flyby for detailed study?
Our previous discussions confirm that a pure slingshot accelerator, even with advanced materials, cannot alone bridge the enormous velocity gap in the short timeframe. So, we need to think about combining different approaches and leverage every possible advantage.
Here are some avenues to explore for intercepting 3I/ATLAS, moving beyond the standalone rotating baton:
1. Leveraging Earth's Orbital Velocity (as you mentioned):
Concept: Launch the probe in the same direction as Earth's orbital motion around the Sun. Earth provides a "free" ~30 km/s boost relative to the Sun. If we can add another ~30 km/s (or even less, strategically) to that, the probe would be moving at ~60 km/s relative to the Sun, potentially matching or exceeding 3I/ATLAS's speed.
Challenge: The current proximity of 3I/ATLAS (closest approach Oct 30, 2025) means there's virtually no time to build and launch a probe with existing rocket technology. The window for an on-time launch using Earth's orbital velocity to reach an intercept point near Earth has likely passed or is too short.
Post-Pericenter Intercept ("Chasing It"): This is where your idea of "catching up after it passes" becomes relevant. If 3I/ATLAS is moving out of the solar system, a probe launched with high velocity after its closest approach could, in principle, follow it. This requires the probe to achieve a Solar-System-relative velocity comparable to, or greater than, 3I/ATLAS.
2. Advanced Propulsion Systems (Even if Not Yet Available):
If we're thinking about "unleashing powers" beyond current, on-the-shelf capabilities, this is where to look.
Nuclear Thermal Propulsion (NTP):
Concept: These rockets heat hydrogen propellant using a nuclear reactor to extremely high temperatures, expelling it at much higher velocities than chemical rockets (Specific Impulse, Isp, ~900-1000 seconds vs. 450 seconds for chemical).
Delta-V Capability: NTP offers significantly higher Delta-V than chemical rockets for the same mass, making rapid transits possible. While no NTP rocket has flown in space yet, ground tests were promising. A 100kg package could potentially achieve an additional ~10-20 km/s with a reasonable mass fraction using NTP, enabling a much faster intercept.
Feasibility for 3I/ATLAS: Not available for launch by October 2025. Development is ongoing, but a flight-ready system is years away.
Solar Electric Propulsion (Ion Thrusters):
Concept: Use electricity from solar panels to ionize and accelerate propellant (e.g., Xenon) to very high exhaust velocities, providing extremely high Isp (~3000-5000 seconds). They produce very low thrust but operate continuously over long periods, allowing for huge total Delta-V accumulation.
Delta-V Capability: Excellent for deep space missions requiring large Delta-V, but they take a very long time to accelerate.
Feasibility for 3I/ATLAS: While high Delta-V is possible, the very low thrust means years of continuous thrusting would be required to reach a high relative velocity. This is not suitable for a short-notice intercept of 3I/ATLAS unless the mission duration is measured in years after launch. For a "chase" scenario over years, it could be a viable primary propulsion.
Future Concepts (Highly Speculative for immediate use):
Fusion Propulsion: Theoretical designs promise extremely high exhaust velocities and significant thrust. Could achieve interstellar velocities, but decades (at least) away from practical application.
Laser/Light Sails (Breakthrough Starshot-esque): Ground-based lasers could push extremely light sails to relativistic speeds. For a 100kg package, this would require a gigawatt-scale laser array and a massive sail, far beyond current tech. The distances and aiming precision for 3I/ATLAS would be immense. Also not an "immediate" solution.
3. Gravitational Assists (Slingshot Maneuvers):
Concept: Use the gravity and orbital motion of planets (Jupiter, Saturn, etc.) to gain significant velocity. This is a common technique for outer solar system probes (e.g., Voyagers).
Delta-V Capability: A Jupiter gravity assist can add 10-20 km/s to a probe's Sun-relative velocity without using any propellant. Multiple assists can accumulate huge Delta-V.
Feasibility for 3I/ATLAS:
Timing is Critical: Planetary alignments are infrequent. To get a high-energy gravity assist that would send a probe out on an intercept trajectory, the planets would need to be in exactly the right positions relative to the launch window and 3I/ATLAS's trajectory. Given the short notice for 3I/ATLAS, finding a suitable, rapid-response gravity assist window is highly improbable.
Trajectory Complexity: Designing such a trajectory is complex and takes significant planning time.
4. "Waiting in Ambush" Missions (like ESA's Comet Interceptor):
Concept: Launch a spacecraft into a "parking orbit" (e.g., at a Sun-Earth Lagrange point, L2) and have it "wait" for a suitable target of opportunity (e.g., a long-period comet or an interstellar object) to enter its capture zone.
Delta-V Savings: By already being in space and at a strategically stable location, the reaction time is shorter, and the Delta-V needed for the intercept can be reduced.
Feasibility for 3I/ATLAS: While excellent for future unknown objects, 3I/ATLAS is already here and passing by. There's no time to launch an "ambush" probe, place it at L2, and then wait for 3I/ATLAS. ESA's Comet Interceptor, while designed for this, is launching in 2029.
5. "Hail Mary" / Rapid Response Mission (Highly Improbable for 3I/ATLAS):
Concept: Have a ready-to-launch, high-Delta-V chemical rocket (e.g., a Falcon Heavy with an extra upper stage, or a proposed "interceptor" class rocket) on standby, capable of launching within days of an interstellar object detection.
Delta-V: Even the most powerful chemical rockets are limited. A large chemical rocket could potentially deliver a 100 kg payload with perhaps 15-20 km/s beyond Earth escape velocity, if launched optimally from Earth (Oberth effect).
Feasibility for 3I/ATLAS: The window is too short. No such rocket or payload is standing ready. Even if it were, the precision targeting required for a fast flyby (let alone rendezvous) on such short notice is a monumental challenge.
The Harsh Reality for 3I/ATLAS (Current Situation):
Given that 3I/ATLAS was discovered only recently (July 1, 2025) and its closest approach is in late October 2025, the timeframe is simply too short for any mission requiring:
Significant design and manufacturing of a new spacecraft.
Heavy-lift launch vehicle availability and integration.
Complex trajectory planning involving gravity assists (which also require optimal alignments).
The long acceleration times of high-Isp, low-thrust propulsion systems.
The Only Remote Possibility (Extremely High Risk/Low Probability):
If humanity had a highly advanced, pre-staged, rapid-response probe at a deep-space location (e.g., in a halo orbit near Jupiter or Saturn for quick access to a powerful gravity assist) equipped with advanced high-Delta-V propulsion (like a high-performance NTP or even a very small, ultra-high-Isp fusion prototype), and if 3I/ATLAS's trajectory happened to align perfectly for a rapid gravity assist from that location, then perhaps a flyby mission could theoretically be mounted. This is squarely in the realm of advanced future capabilities, not present reality.
Conclusion:
While your rotating baton concept could indeed provide a few kilometers per second of Delta-V for a 100 kg package, making it a valuable first stage in a multi-stage acceleration system, it is not sufficient on its own to intercept 3I/ATLAS given the current timeline and its immense velocity relative to the Sun.
Unfortunately, for 3I/ATLAS, the most likely outcome is that we will observe it from afar with ground and space-based telescopes, learning what we can as it makes its fleeting pass through our solar system. The challenge of intercepting such fast-moving, short-notice interstellar visitors remains one of the grandest and most difficult problems in space exploration, requiring a leap in detection, rapid response, and propulsion capabilities.
Perhaps the knowledge gained from this encounter will accelerate the development of the very technologies needed for the next 3I/ATLAS!

(th)

tahanson43206 · 2025-07-31 07:30:46

This post is about an analysis that appears to show that the Juno spacecraft at Jupiter could come close to 31/ATLAS if NASA were to authorize diversion from it's primary mission.

https://www.yahoo.com/news/articles/exi … 48643.html

Futurism
Existing NASA Spacecraft Could Intercept the Weird Interstellar Object Cruising Into Our Star System
Victor Tangermann
Wed, July 30, 2025 at 2:21 PM EDT
Earlier this month, astronomers noticed a mysterious object speeding toward the inner solar system from outside of our star system.
It's an exceedingly rare occurrence, marking only the third confirmed interstellar object to have ventured into our solar system, all of which have been detected since 2017.
Harvard astronomer and alien hunter Avi Loeb was quick to raise the tantalizing — albeit admittedly far-fetched — possibility that the object, dubbed 3I/ATLAS, could have been an alien probe sent to us by an intelligent civilization.
And now, in a twist right out of Stanley Kubrick's 1968 "2001: A Space Odyssey," he's suggesting a way that we could use an existing spacecraft to intercept the object's path to test that very hypothesis.
In a yet-to-be-peer-reviewed paper, the researcher argued that NASA's Juno spacecraft, which was designed to study Jupiter and launched in 2011, could get eerily close to 3I/ATLAS by March 14, 2026.
Juno would have to apply a thrust of 1.66 miles per second on September 14, 2025, Loeb calculated, to intercept the mysterious object's path.
"The close encounter of 3I/ATLAS to Jupiter provides a rare opportunity to shift Juno from its current orbit around Jupiter to intercept the path of 3I/ATLAS at its closest approach to Jupiter," he wrote in a new blog post about the proposal.
While it's technically not a rendezvous — the object's "excessively high hyperbolic speed" wouldn't allow for such a meeting — Juno's arsenal of scientific instruments "can all be used to probe the nature of 3I/ATLAS from a close distance," Loeb argued.
Whether the spacecraft, which has been soaring through space for 14 years now, would have enough fuel to even pull off such a stunt remains unclear.
But Loeb argues it could "rejuvenate Juno’s mission and extend its scientific lifespan beyond" the potential intercept some eight months from now.
The news comes as scientists are still racing to get a better sense of 3I/ATLAS' exact nature. Last week, the recently inaugurated Vera C. Rubin Observatory in Chile had a closer look, finding that the object is roughly seven miles wide, making it the largest interstellar object ever spotted.
The prevailing and most widely accepted theory suggests that 3I/ATLAS is a comet, with previous observations supporting the idea that its coma, or surrounding cloud of ice, dust, and gas, was anywhere up to 15 miles across.
The Vera C. Rubin observations identified large amounts of dust and water ice surrounding its solid nucleus, as detailed in a July 17 preprint, further adding evidence that it's a comet.
Yet many questions surrounding its origin remain a mystery. Some researchers believe it came from our galaxy's "thick disk," a dense layer that features chemically distinct populations of stars.
Other researchers suggest it could be around three to 11 billion years old, dating it back to the earliest days of the Milky Way.
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It seems unlikely that NASA will find Loeb's suggestion compelling enough to fire up Juno's thrusters for an intercept. But it's an extremely rare opportunity to finally get a close glimpse of an interstellar visitor nonetheless — so hopefully they're at least checking his math to see if it's possible.

In a separate topic, I've investigated the potential of a rail gun to match orbit with 31/ATLAS....

Assuming only 30 km/s is needed (taking Earth's 30 km/s into account) a track 5 kilometers long could (apparently) achieve 30 km/s at an acceleration of 30,000 G's, which (I understand) is the highest that humans have achieved in artillery electronics.

An instrument that size could be constructed on the Moon.

(th)

Calliban · 2025-07-31 10:48:18

Interesting. Does Juno have enough onboard propellant for the requisite dV?

As an aside, it isn't necessary to match velocity for an intercept. A flyby could be carried out at much lower dV. The object will cross Earth's orbit.

tahanson43206 · 2025-08-09 19:48:45

It appears that at least on Congressperson has taken an interest in the Juno mission proposal.

https://www.yahoo.com/news/articles/con … 56578.html

Futurism
Congressperson Urges NASA to Send Its Jupiter Probe Chasing in Pursuit of the Weird Visitor Coming From Interstellar Space
Victor Tangermann
Sat, August 9, 2025 at 11:00 AM EDT
Earlier this year, astronomers spotted a mysterious interstellar object, dubbed 3I/ATLAS, hurtling through the solar system at a blistering speed.
It's only the third confirmed interstellar object to have ventured into our solar system — all over the past few years, owing to more sophisticated space-observing technology — and scientists are eager to have a closer look.
Besides detailed observations by the Very Large Telescope in Chile and NASA's Hubble Space Telescope, Harvard astronomer and alien hunter Avi Loeb called on using the space agency's Juno spacecraft to intercept the object's path to get a first-hand look.
Loeb, who made headlines last month after suggesting 3I/ATLAS may be an alien probe sent by an intelligent civilization, argued in a blog post that the "close encounter of 3I/ATLAS to Jupiter provides a rare opportunity to shift Juno from its current orbit around Jupiter to intercept the path of 3I/ATLAS at its closest approach to Jupiter."
The unique opportunity caught the attention of Representative Anna Paulina Luna (R-FL), who sent a letter to acting NASA administrator Sean Duffy, encouraging the agency to follow Loeb's suggestion.
"It is recommended that NASA conduct a study to assess how much fuel is left in Juno's engine, and I support an extension of the Juno mission at least until mid-March 2026 at a cost of about $15M per 6 months from the current expiration date of mid-September 2025," the letter reads.
Experts, however, were quick to throw cold water on Loeb's plan, which happens to resemble the plot of Stanley Kubrick's 1968 sci-fi epic "2001: A Space Odyssey."
"Juno does not have enough fuel to visit 3I/ATLAS," Penn State astronomy professor Jason Wright tweeted. "Its main engine is also malfunctioning. [Loeb] does (or should) know this because his team was in touch with [Juno principal investigator Scott Bolton]."
"An extended mission for Juno would be awesome, but a visit to 3I/ATLAS makes no sense," he added.
The spacecraft was launched almost exactly 14 years ago, entering a polar orbit of Jupiter roughly five years later. It was only planned to study the planet until 2018, but it has since doubled the length of its originally planned mission.
Not everybody agrees that a mission to visit 3I/ATLAS is out of the question, though.
Juno's "current orbit allows it to view Jupiter up close, and its visits to Io [a moon of Jupiter] in 2023 [and] 2024 exposed it to a lot of radiation," University of Kent space professor Mark Burchell told New Scientist. "So it is no surprise it is now showing anomalies in performance that need rebooting."
"Could it be re-tasked?" he added. "In theory, if it can be done, and the instruments work, then there is novel data there."
Unsurprisingly, intercepting an interstellar visitor that's screaming through outer space at 37 miles per second would be no easy feat even with brand new hardware. Any mission would need a lot of fuel and time to get anywhere near it.
According to a yet-to-be-peer-reviewed paper by a team from Michigan State University, a new mission would need to accelerate at 15 miles per second on the day of discovery — which was July 1, so the clock is ticking — to get there in time.
However, "spacecraft at Mars could be used to make valuable observations" around late November, when 3I/ATLAS hits its perihelion, or when it makes its closest approach to the Sun.
"The perihelion of 3I/ATLAS will not be easily observable from Earth-based observatories, as the object will be on the opposite side of the Sun and at a low solar elongation angle," the paper reads. "However, the object will approach within 0.19 au [or 17.6 million miles] of Mars, and we encourage nearby spacecraft equipped with visible, UV, and IR spectrographs and cameras to attempt to capture data on this object’s closest approach."
The European Space Agency's Jupiter Icy Moons Explorer (JUICE) may also be able to get a look. The agency's Luca Conversi told New Scientist that "we are aware of this precious opportunity and are currently exploring the technical feasibility."
"I’m not sure it is feasible to send it to the comet: unfortunately astro-dynamics is more complicated than what we see in sci-fi movies," he added, "and it is not easy to change the course of spacecraft."
Time is quickly running out, and visiting 3I/ATLAS is starting to look like a Herculean task. But to scientists, it's an endeavor worth exploring nonetheless.
"The closest approach to Earth will be in December," said coauthor and fourth-year Michigan State undergraduate Atsuhiro Yaginuma in a press release last month. "It would require a lot of fuel and a lot of rapid mobilization from people here on Earth."
"But getting close to an interstellar object could be a once-in-a-lifetime opportunity," he added.
More on the object: Existing NASA Spacecraft Could Intercept the Weird Interstellar Object Cruising Into Our Star System

(th)

Void · 2025-08-11 14:44:46

Lets consider this like a ghost story around a campfire as to how serious to take it.

https://www.msn.com/en-us/news/technolo … r-AA1Kgdkd Quote:

Harvard physicist says massive interstellar object could be alien probe on 'reconnaissance mission'
Story by Sophia Compton • 1d • 2 min read

Maybe consider taking it 1% serious.

In a darker view of aliens, if they did reconnaissance of Mars, Venus, and Jupiter, they might consider that we are becoming a potential threat if they see evidence of a developing Kardashev 2 civilization.

This would presume that they already know that the Earth has life on it.

So, my guess is that it would be bring friendly contact, but perhaps a beat down, for us, if we look like a problem.

But yes it is at least 99% likely that it is a interstellar dead object with no intelligence associated with it.

I find it hard to believe that they, (If they existed) would expend so much effort on such a large object. I would expect them to be stealthy instead. But if they are aliens and actually exist, how could I really know how they would think?

Ending Pending

Last edited by Void (2025-08-11 14:50:52)

Void · 2025-08-13 12:14:27

I have been thinking about it some more. Actually I think the chances of Aliens is less than 1%. Very much.

But the assumption that an alien people want to talk to us is silly. Sometimes cultures don't want to be bothered. For instance at one time "Japen".

If Aliens knew that there is life on Earth, but don't want to be bothered, they could monitor us while hiding themselves, and yet not be sure that they would not be detected if we had become much more advanced than expected. So, basically checking up on us and showing a fist, might be what they might do.

This presumes a little on the thinking of Isaac Arthur, that Aliens in competition with other Aliens might fear punishment if they molest a baby culture too much. But showing a fist and saying don't make us use it could be allowable/tolerated by a community of quiet aliens, in a Dark Forest notion of reality.

Ending Pending

Last edited by Void (2025-08-13 12:18:34)

New Mars Forums

Announcement

#1 2025-07-05 12:13:02

3I/ATLAS Comet Will Swing by Sol

#2 2025-07-05 12:16:58

Re: 3I/ATLAS Comet Will Swing by Sol

#3 2025-07-07 15:36:18

Re: 3I/ATLAS Comet Will Swing by Sol

#4 2025-07-08 08:49:05

Re: 3I/ATLAS Comet Will Swing by Sol

Introduction

Current Delta-V Capabilities

Why 30 km/s Delta-V is a Huge Challenge with Current Tech

Highest Accelerations Achieved (Non-Propulsion Specific)

Future Possibilities: Beamed Energy Propulsion and Lunar Bases

Is Anyone Working on This?

Challenges Remain

Conclusion

#5 2025-07-08 10:53:49

Re: 3I/ATLAS Comet Will Swing by Sol

#6 2025-07-29 09:18:23

Re: 3I/ATLAS Comet Will Swing by Sol

#7 2025-07-29 10:27:37

Re: 3I/ATLAS Comet Will Swing by Sol

Scenario Parameters:

Calculations for Tension and Material Stress:

3. Required Material Strength and Cross-Sectional Area (Initial Estimate):

4. Critical Factor: The Mass of the Tether Itself

Conclusion on Material Viability:

Substantially reducing the instrument package mass.

#8 2025-07-29 11:18:15

Re: 3I/ATLAS Comet Will Swing by Sol

Analysis of Slingshot Accelerator Material Requirements: Revised Parameters

Revised Scenario Parameters:

Calculations for Tension and Material Stress (Revised):

3. Required Material Strength and Cross-Sectional Area (Initial Estimate, Ignoring Tether Mass):

4. Critical Factor: The Mass of the Tether Itself (Recalculated)

Conclusion on Material Viability with Revised Parameters:

Moving Forward:

#9 2025-07-29 11:45:37

Re: 3I/ATLAS Comet Will Swing by Sol

#10 2025-07-29 11:56:57

Re: 3I/ATLAS Comet Will Swing by Sol

#11 2025-07-31 07:30:46

Re: 3I/ATLAS Comet Will Swing by Sol

#12 2025-07-31 10:48:18

Re: 3I/ATLAS Comet Will Swing by Sol

#13 2025-08-09 19:48:45

Re: 3I/ATLAS Comet Will Swing by Sol

#14 2025-08-11 14:44:46

Re: 3I/ATLAS Comet Will Swing by Sol

#15 2025-08-13 12:14:27

Re: 3I/ATLAS Comet Will Swing by Sol

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