You are not logged in.
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)
Offline
Like button can go here
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)
Offline
Like button can go here
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)
Offline
Like button can go here
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)
Offline
Like button can go here
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)
Offline
Like button can go here