You are not logged in.
This topic is another spin-off of the pioneering visionary work of RobertDyck.
In attempting to find a solution to the challenge of providing propulsion for Large Ship (Prime), GW Johnson worked out a set of variations on propulsion using space tugs.
This work is documented in the topic: GW Johnson Postings
Background documents are available in the ExRocketman Wordpress web site.
A video presentation is available courtesy of the web site: northhoustonspace.org.
Look for the presentation given April 9, 2022, at Houston, texas.
My expectation for this topic is that it will follow creation and growth of a trillion (US) dollar industry.
My expectation is that the Space Tug service will combine with on-orbit refueling services, as well as supply of propellant using atomic power (of some kind) to manufacture the liquids needed.
With any luck, the human resources to create a Space Tug organization in the US will come together in the next few weeks.
(th)
Offline
Like button can go here
Harvesting of celestial treasure is a natural sideline for a Space Tug company.
While any of the numerous objects floating (if that's the right word) around the Solar System are fair game, the newly reported Giant Comet is particularly interesting (to me for sure), because it offers some ** really ** useful materials in great quantity, and it will do so reliably for an extended period of time.
(th)
Offline
Like button can go here
We have a thought process under way about where to put a Space Taxi topic....
While we wait for resolution of that question, it appears that members of the forum, with the sole exception of GW Johnson, do not have a full understanding of the nature of Dr. Johnson's proposal.
Everything is thoroughly documented in the GW Johnson topic. Links to all presentation files are available, so the files can be pulled from Dropbox.
The mental image that may come to mind with the expression "space tug" is some dinky little ion drive that moves a satellite that is in orbit by some tiny increment.
The proposal of GW Johnson is for a massive rocket able to toss a 5000 Metric Ton space ship towards Mars, so that over 90% of the impulse needed for the flight is imparted by the tug, and the small residual is made up by the onboard propulsion system of the vessel.
Any Nation that has the foresight to fund development of the Space Tug will have a ready market, because there will be so much to be gained by existing rocket teams thinking about the Mars and other deep space problem. The more impulse that can be transferred to the space tug, the more mass remains available for use at the destination, including velocity adjustment at the destination, and even propulsive landing.
(th)
Offline
Like button can go here
For SpaceNut re #18
Thanks for a very NICE follow up and collection of links for study about space tugs.
The Wikipedia entry specifically mentioned rocket pusher implementations such as the one proposed by GW Johnson, but the Wikipedia editor begged off dealing with those at this time, because they do not yet (appear to) exist.
This topic is about Hydrogen Peroxide as an oxidizer, so I'm hoping our forum members will help to develop this into a robust topic.
This particular oxidizer is particularly suitable for a huge Solar System spanning space tug, because it can be maintained indefinitely in space.
The low ISP of a rocket engine using this oxidizer is easily compensated for by employing as many engines as the customer needs for their application.
There is NO need to be limited to a single rocket design such as is needed to launch from Earth, because there is no limit to the size of the mounting frame that can be used for this purpose in space.
There is NO need for streamlining or any other aspect of rocket design that is required for launch from Earth.
(th)
Offline
Like button can go here
That is why we started this particular topic as the beamed energy drive for kbd512 was just that to not just boost but to push the large ships design.
As done in the large ship for the convention the tugs are a bidirectional device not only to send it to mars but to get it back from mars knowing that refueling of these can at the start be done via earth return of them as mars will not have the infrastructure to do more than refill the taxi that is brought to off load the passengers and cargo once they arrive at mars orbit to the planet's surface.
The ability to send 5,000 tons was equal to 13 starships refueled on orbit and another 13 to bring it back without the taxi to bring them to orbit in earth orbit or to bring them down from the large ship once it reached mars destination.
What would be a good exercise would to see if a modified starship could launch from earth only passengers to the ship and do the same at the destination to get fuel allotments for launch and descent requirements even if it only can do it once permission for the total population. So how long would they need to be on the ship dictates how much cargo needs to be present for either ends use.
Offline
Like button can go here
Orbit changes can be quite nonintuitive, until and unless one becomes very familiar with making orbit calculations, and I mean by hand, not with software! There is no intuition to be gained when using software!
News broadcasters became caught up in this dilemma decades ago during the Mercury/Gemini flights in the 1960's. They talked about "speeding up to slow down", etc, which tells me they never did figure it out.
When operating in an elliptical orbit about the Earth, there is a perigee where speed is highest, and an apogee where speed is lowest. Just to be clear, perigee is min orbit altitude, while apogee is max orbit altitude. This really is simply conservation of mechanical energy: kinetic plus potential.
If you want to change your orbit's apogee, you make the burn at perigee. A posigrade burn increases total orbit energy, raising the apogee. A retrograde burn decreases total orbit energy, decreasing apogee. Perigee, where you make the burn tangentially to the orbit, is unchanged.
Conversely, if you want to change your orbit's apogee, you make a burn tangential to the orbit at its perigee. Posigrade increases energy, raising apogee. Retrograde decreases energy, lowering apogee. But your perigee is unchanged.
Edit 2-21-2023: What meant to say here was this: Conversely, if you want to change your orbit's perigee, you make a burn tangential to the orbit at its apogee. Posigrade increases energy, raising perigee. Retrograde decreases energy, lowering perigee. But your apogee is unchanged.
All of this applies to elliptic (closed) orbits, a classical 2-body problem that has closed-form solutions known for centuries now. Earth (or any other central body) is at one focus of the ellipse, the other focus being empty. R is the vector from the central body (at one focus, not the center) to the thing in the orbit, which varies between a min R and a max R. Speed along the orbit depends upon R as V = [GM(2/R - 1/a)]^0.5, where Vper is at Rmin, and Vapo is at Rmax.
The size of the ellipse major axis is 2a = Rmin + Rmax. The eccentricity e = (Rmax - Rmin)/(Rmax + Rmin). The distance from the center of the ellipse to one focus is c = e*a. The semi-minor axis length b^2 = (a^2 - c^2). The equation of the ellipse with "a" along the x-axis, and the center of the coordinates at the center of the ellipse, is x^2/a^2 + y^2/b^2 = 1. If you shift your coordinates such that the center of the ellipse is at (h,k) instead of (0,0), then the equation of the ellipse is (x - h)^2/a^2 + (y - k)^2/b^2 = 1.
GW
Last edited by GW Johnson (2023-02-21 10:32:10)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Like button can go here
https://finance.yahoo.com/news/vast-acq … 28587.html
4
Aria Alamalhodaei
Tue, February 21, 2023 at 9:00 AM EST·4 min read
Vast Space, a company that emerged from stealth last September with the aim of building artificial gravity space stations in low Earth orbit, has acquired space tug startup Launcher, TechCrunch has exclusively learned.The acquisition, a first for Vast, will give the company access to Launcher’s Orbiter space tug and payload platform and its liquid rocket engine, E-2. Under the terms of the deal, Vast will also absorb all of Launcher’s talent, including Launcher founder Max Haot, who will join as president. The two companies told TechCrunch that the deal has been in the works for months, with both signing a Letter of Intent to acquire back in November.
Stay ahead of the market
The deal could be a big accelerator for Vast; the company’s founder, billionaire crypto pioneer Jed McCaleb, said Vast will use the Orbiter tug to test space station subsystems and components in orbit as soon as June of this year, and then again around October. Those two missions, which will be Orbiter’s second and third flights, will also carry customer payloads. Vast will continue to operate Orbiter as a commercial product; Haot said they had more than five customer contracts and are signing more.Haot added that the space tug’s abilities, like approaching and moving away from spacecraft and hosting payloads, as well as its technologies like flight software, avionics and guidance, navigation and control systems will complement development of the space station.
Launcher's Orbiter spacecraft. Image Credits: Launcher/John Kraus (opens in a new window)
Launcher made news last week when it said that its first Orbiter mission, which took place at the beginning of January, ended in failure after the spacecraft’s power systems malfunctioned. Despite that setback, Haot told TechCrunch that the results of the mission were “well above industry average.”
“We know exactly what went wrong. We were fully operational for the duration of the battery and we fell short of deploying our customers because of a power issue,” he said. “So Vast, Jed and us are actually extremely proud of what was achieved. We have two more flights this year. […] If you think about it, the odds that this is a stable platform by the end of the year are very high.”
The article continues online if anyone is interested ...
We've been talking about Space Tugs recently.
Launcher appears to be aiming for that market.
(th)
Offline
Like button can go here
https://www.yahoo.com/news/nasa-wants-d … 30681.html
Space
NASA wants new 'deorbit tug' to bring space station down in 2030Mike Wall
Mon, March 13, 2023 at 5:00 PM EDTThe International Space Station photographed by Expedition 56 crew members from a Soyuz spacecraft after undocking, Oct. 4, 2018.
The International Space Station photographed by Expedition 56 crew members from a Soyuz spacecraft after undocking, Oct. 4, 2018.NASA aims to develop a spacecraft capable of steering the International Space Station (ISS) to a controlled destruction in Earth's atmosphere when its time in orbit is up.
We first learned about this plan on Thursday (March 9), when the White House released its 2024 federal budget request. NASA's $27.2 billion allocation included $180 million "to initiate development of a new space tug" that could safely deorbit the ISS over the open ocean after its operational life ends in 2030, as well as potentially perform other activities.
More details emerged on Monday (March 13) during a press conference NASA held to discuss the proposed budget, which must be approved by Congress to be enacted. For example, we've now got a ballpark price tag for the deorbit tug, preliminary though it may be.
"A cost estimate we had was a little short of about $1 billion," Kathy Lueders, NASA's human spaceflight chief, said during the press conference. "Our goal is to go out with an RFP [request for proposals], and then, obviously, when we get the proposals, then we're hoping to get a better price than that. But this gives us a healthy start in '24 to get that critical capability onboard."
Related: The International Space Station will eventually die by fire
The new tug will supplement existing deorbit capabilities of the International Space Station partners (the space agencies of the U.S., Russia, Europe, Canada and Japan). The current plan for bringing the station down safely relies upon engine burns by robotic Progress cargo vehicles, which are provided by Russia.
"But we're also developing this U.S. capability as a way to have redundancy and be able to better aid the targeting of the vehicle and the safe return of the vehicle, especially as we're adding more modules," Lueders said.
"As you've seen in the past and over this last year, us having these redundancies has been very, very important for both ourselves and our partners," she added. "And so, having a U.S. deorbit vehicle is another key linchpin in our space operations and deorbit strategy of the ISS."
The recent examples to which Lueders was likely referring are coolant leaks that occurred on two separate Russian vehicles docked to the ISS: A Soyuz crew spacecraft lost all of its coolant to space on Dec. 14, 2022, and a Progress sprang a leak of its own on Feb. 11.
Russia has attributed the Soyuz leak to a likely micrometeoroid strike and linked the Progress issue to an "external influence," perhaps a problem incurred during launch. But the investigation into the two leaks continues.
In addition, Russia has voiced a desire to leave the ISS partnership early (at some point "after 2024") to focus on building its own outpost in low Earth orbit. This information likely factors into NASA's deorbit-tug plans, as does Russia's ongoing invasion of Ukraine, which has severed many of Russia's space partnerships.
Related: Russia's war on Ukraine has caused lasting damage to international spaceflight cooperation
Related stories:
(th)
Offline
Like button can go here
Deorbiting the ISS is just the same as deorbiting Skylab would have been, except ISS is way bigger so you need more total impulse to get the right dV, which is pretty close to 0.10 km/s.
You don't need a real tug, you just need a propulsion item, the station has its own command-able attitude control. I'd suggest a reasonably big solid motor from one of those outfits, fitted to dock at an appropriate port on the station, such that the thrust line goes through the cg pretty close. Not an SRB, but not a Sidewinder, either.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Like button can go here
A lot more dV and we can reuse it, just use the panels from the station to power an ion drive engine to send it on its way.
Offline
Like button can go here
For SpaceNut re #10 and sentiment to salvage space station ....
Have you looked at any of the detail behind the decision to deorbit the station? I have not, so can't help, but my impression is that the station is deteriorating.
Could there be an issue with hull integrity? Those modules are being held at Earth sea level pressure. The walls are flexing with every orbit, because the heat in the Sun and freeze in the cold of the shadow.
However, since this ** is ** the Space Tug topic, a Space Tug could probably lift the station to higher orbit, given enough time with an ion drive.
I suspect that would be one hefty ion drive. You should be able to discover the mass of the station and the solar cell output that is available. From those two figures, you may be able to calculate the mass needed for ion propellant, and the duration of the run, if you decide where you want the station to go.
(th)
Offline
Like button can go here
Mostly the Russian stuff.
Much of the station with US modules has had many upgrades that have been done over time.
The fact that NASA has contracts with Axiom for more changes means we have plenty of potential to not ditch all of the station.
I saw a $1 billion dollar ISS tag for the tug NASA Wants $180M for a 'Space Tug' to Deorbit the International Space Station
Offline
Like button can go here
OASIS Infrastructure Concept Images NASA RASC https://spacecraft.ssl.umd.edu/old_site … asis_pics/ Long-forgotten Shuttle/Centaur https://www.cleveland.com/science/2011/ … ntaur.html
If I recall correct in another thread GW Johnson discussed refueling infrastructure is not in extreme elliptic orbit but for the SpaceTug to move in low orbit GW Johnson also recommend a polar orbit at the moon.
D-Orbit is an Italian company that has successfully worked on the concept. ' D-Orbit Launch and Deployment Services/Space Logistics Company'
https://www.eoportal.org/other-space-activities/d-orbit
I believe one year ago China was testing something and the Chinese had a Shijian-21 debris mitigation satellite docked with defunct Beidou sat.
https://spacenews.com/chinas-shijian-21 … satellite/
Solving space junk problem may require lasers and space tugs
https://news.yahoo.com/solving-space-ju … 23207.html
Offline
Like button can go here
GW Johnson has prepared diagrams to illustrate how space tugs would work.
The scenario for departure from Earth looks solid to me.
The scenario for arrival back at Earth is not yet fully realized. At the moment, GW's design requires the arriving vessel to shed some of it's velocity at Earth. The preferred solution will relieve the arriving vessel of ** all ** responsibility for changing velocity.
The technical issue (as I understand it) is how to give the space tug the high velocity it needs to match orbit with the arriving vessel. In a preliminary assessment, GW appears to be skeptical that ** any ** engine design presently available could perform that feat.
GW is continuing to work the problem. If it ** can ** be solved, I am confident he will find a solution.
(th)
Offline
Like button can go here
The specific problem to be solved is how to "catch" Artemis II's Orion capsule after it leaves the Moon, and before it reaches the Earth's atmosphere. The heat shield installed on Artemis II is identical to the one that performed poorly in Artemis I.
Because not everyone follows these matters closely, to summarize: The NASA personnel who designed the Artemis I heat shield tried to save some money. Their cheaper design did not burn all the way through to aluminum, but it did lose patches of heat shield material at random locations across the expanse of the shield. The Apollo design did not suffer any comparable damage.
The Artemis II heat shield is made in the same way as that for Artemis I. This means that the shield ** will * shed blotches of material at random locations, but this time there will be human beings on board.
GW Johnson has offered to help NASA replace the defective heat shield, since he has experience (a) and (b) he knows how the Apollo shields were made.
It appears that NASA has locked the Orion capsule into it's launch configuration, so it is unlikely the Artemis II system will be given a new heat shield. An alternative is to use a space tug to catch Orion for Artemis II before it enters the Earth's atmosphere. Such a tug could be built independently of the Artemis II system, and launched at the same time as Artemis II.
If the vehicle were sent to the Moon along with Artemis, then it could dock with Orion at the Moon, and return the capsule safely to Earth orbit.
At Earth, after dropping Orion's velocity so it can orbit in LEO, Orion could then return to Earth whenever it is ready. The descent from LEO is much less challenging than the return from the Moon would have been.
Hopefully future Artemis heat shields will be made correctly.
(th)
Offline
Like button can go here
From what I have seen to read, NASA program managers were choosing from 3 options: (1) do nothing, (2) modify the entry trajectory to reduce the severity of the heating a little but keep the questionable heat shield, and (3) replace the heat shield with something better. Option 3 means unstacking the rocket and another year's delay at least. The other 2 options do not.
I believe they chose either option 1 or option 2, most likely 2. They're close-mouthed about this, because they do not want the general public to know they deliberately risked astronaut lives to save time and money, the direct cause of both fatal Shuttle losses.
Yes, I got my original letter-to-Bill Nelson into the hands of a real NASA heat protection engineer David E. Glass, along with some 3 decade old ramjet insulation test photos showing a very similar chunk loss pattern (from tests that I ran back then). I expect they might try a "better design" for the Artemis 3-and-subsequent heat shields, which haven't been built and installed yet, and which is where my information might be used. I have not heard back from him, after acknowledging receipt of the items.
Any sort of space tug rescue option would be something for the indeterminate future. There is nothing capable currently flying that we could use for this. I have not been able to figure the rendezvous dV for such a scenario, but I do know it would be enormous, and it would have to take place on a timeline only some minutes away from entry.
GW
Last edited by GW Johnson (2024-11-26 15:28:10)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Like button can go here
For All re GW's post #16
The problem would appear to be solvable if we put the rescue vehicle AT THE MOON, before Artemis arrives.
Humans have demonstrated the ability to dock with orbiting vehicles at the Moon. This tells me the problem is solvable there.
GW Johnson has explained the computational difficulty of trying to catch the capsule on it's way home from the Moon, and for that reason I am proposing we take another look at the problem.
The Artemis mission plan (as I understand it) is to place the capsule and a support module at the Moon. After the mission is completed, whether it is just circling the Moon or spending some time there in multiple orbits, the Artemis systems would dock with the rescue vessel, and the combined system would return to Earth LEO. Once the Orion capsule is released in LEO, it will be able to return to the surface without risk, since the heat shield was already demonstrated to be able to survive a Lunar return, despite flaking due to poor design.
The detail that I am adding to this scenario is to use the Artemis component that would have shoved the vehicle toward Earth by configuring it so it can give both the rescue vehicle and the capsule a shove toward home. How that would be done would depend upon design of the rescue vehicle, which has not yet happened.
The reason I think this entire concept might be possible is that SpaceX time is much faster than NASA/contractor time.
Most importantly, successful implementation of this concept would be a precedent for future space rescues as humans venture out away from Earth in greater numbers.
(th)
Offline
Like button can go here
Artemis-2 will NOT be orbiting the moon. It cannot, that would be a 1-way suicide trip. Artemis-2 is a flyby of the moon, continuing on into cis-lunar space before returning home at about escape speed.
SLS Block 1 can put the Orion/service module only into trans-lunar injection. The interim upper stage is essentially out of propellant after doing that. The service module is undersized, compared to the mass of the Orion capsule, quite unlike Apollo. There is enough dV to enter low lunar orbit, but not to leave it.
This thing was designed only to barely reach that crazy halo orbit about the moon, it cannot reach an Apollo-like low lunar orbit.
GW
Last edited by GW Johnson (2024-11-26 19:10:00)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Like button can go here
For GW Johnson re #18
If you have a spare moment, please clarify the term 'interim upper stage"
Is that a ** 3rd ** stage, or is that the second stage.
I ask because if it is a ** 3rd ** stage then one of your space tugs could shove that stage, along with Orion and the Service module, onto it's around-the-Moon trajectory, and the "interim upper stage" could provide the 3.1 km/s to decelerate into LEO, which would insure a safe return for the astronauts.
If you can design a vehicle capable of performing that boost, and NASA doesn't have to do anything to it's hardware, then the decision makers might be willing to consider it. They ** would ** have to adjust their flight plan, but the employees who would do that work will be paid anyway, so no new money would be required.
The ** new ** money would have to be allocated to design, build, launch and assemble the Space Tug in LEO, but after that investment, the Space Tug would remain available as a reusable resource, owned and controlled by the United States (via it's agents).
I am thinking of four Starship bodies bolted together in a cluster, so that the vessel has plenty of power to shove a heavy load on a meaningful journey.
(th)
Offline
Like button can go here
"Interim upper stage" (IUS) is the smaller second stage of the SLS as embodied in the Block-1 configuration that cannot reprise even Apollo-8 with Orion and its service module. This is supposed to be replaced with a substantially larger second stage in the Block-1B configuration, which will be able to do significantly more. Block-2 replaces the SRB's with liquid strap-on boosters, adding yet a bit more capability. I have my doubts as to whether there will ever be a Block-1B, much less a Block-2. Not with per-launch costs already climbing past $4B for a single SLS/Orion flight. I've heard the SLS price without Orion is nearer $2+B, but I rather doubt that to be true. So much has turned out to be false already.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Like button can go here
GW,
SLS was deliberately designed to be another Congressionally-sponsored boondoggle, so that's what it is.
Offline
Like button can go here
For GW Johnson re #20
Thanks for your clarification that the "interim second stage" is a true "second" stage....
Can you confirm the "interim second stage" is intended to shove the Orion capsule and the Service module toward the Moon fly-by?
I assume (for now) that is the case....
My proposal then is to keep the "interim second stage" attached to the remainder of the stack, so it can be relit to decelerate the package on it's way back from the Moon. It this proposal is viable (and it may not be for many reasons), then the Space Tug for Departure would have to be sized to push the entire upper stack to and around the Moon.
That would require a beefy Space Tug, but nothing would be expended except fuel, so the vessel would be available for other missions upon return from it's high ellipse loop back to LEO. The reusable feature extends to the SLS components, since they too would be retained in LEO after return from the Moon. Only the Orion capsule would return to Earth, and that safely since the stress of a LEO return is so much less than the Lunar return.
Humans need to learn how to stop leaning on aerobraking sooner rather than later due to the congestion already happening. A vehicle returning from the Moon or Mars or anywhere else is NOT going to be able to evade satellites in LEO that wander into the flight path. I am confident that at SOME point Space Traffic Control is going to be implemented, just as air traffic control has been implemented in every Nation large enough to host an airfield.
(th)
Offline
Like button can go here
The IUS is supposed to be enough to send Orion to Gateway in that halo orbit and still come home, which is supposedly enough for the lunar flyby without going to the halo orbit. But I cannot run the numbers for myself without data to populate weight statements.
Why not just keep a Starship in orbit and just use it as a space tug? You have to refill it fully, but so what? 120 tons inert, 1200 tons max propellant load, 3 sea level engines at about 230 m.ton-f thrust each in space, and 3 vacuum engines at about 250 m.ton-f thrust each. That's a max thrust capability of some 1440 m.ton-f with all 6 burning. You won't need anywhere near that much thrust.
The real trick is figuring out about what dead-head payload the Starship could push from LEO to an elliptic departure, and still get back unladen to LEO. And, what dead-head payload a Starship could go unladen to elliptic, and still retrieve back to LEO.
My crude numbers say 497 metric tons payload at departure, but only 175 metric tons payload at arrival. Both using full propellant loads as filled in LEO. I use 2 vac Raptors at full thrust while laden, but only 1 vac Raptor while unladen.
If you leave the heatshield and flaps on it, you can bring it home for repairs anytime anything wears out, like an engine.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline
Like button can go here
For GW Johnson re #23
The idea of using one Starship as a Space Tug for Artemis is certainly interesting.
I've been thinking about how to mate the bottom of the "Interim Second Stage" of Artemis to the Space Tug. I had been thinking you'd want to create the Space Tug as a space-only vessel, so you could avoid the restrictions of an aerodynamic shape, and the mass penalty of the shielding. Adapting a Starship for use as a Space Tug is certainly interesting.
To serve as the LEO to Moon booster for Artemis II, the Starship would (presumably) need to be fitted with a superstructure over the nose capable of mating with the base of the SLS Interim Second Stage.
Could that docking apparatus be fitted on Earth? It could be enclosed in a disposable fairing for the flight to space. In LEO the vessel would be refueled ready for docking with Artemis.
I presume the Interim second stage of Artemis II is able to restart. It would need to push itself and it's burden into LEO in order to mate with the Space Tug. The Space Tug would give the Artemis stack a shove sufficient to send it around the Moon per NASA's current flight plan. The Interim Second Stage would slow the stack into LEO on the return.
Meanwhile, the Space Tug would fly that long ellipse you've described in numerous papers, presentations and YouTube videos, and then slow itself for a return to LEO for the next mission.
If we follow through on ** this ** scenario, then the only new hardware needed is the docking structure to fit on the nose of the Space Tug Starship.
I think that trying to save the Starship's ability to return to Earth for maintenance is do-able, if you can think of a way to fit the docking stucture on the nose of the Starship.
Why not just cut ties with Earth?: That way you can modify the Space Tug for missions without having to worry about heat shield tiles or anything else. If the vessel needs a new engine the work can be done in the on-orbit maintenance facility you've talked about.
Your interest in returning the Starship Space Tug to Earth for maintenance reminds me of the debacle that occurred when the Space Shuttle was in design, and the Air Force wanted features suitable for military activities. My recommendation is just build a Space Tug and leave it in space.
However, if the folks who pay the bills for this venture want the ship to return to Earth, that that is what you'll get.
Todo item:
We need to find out the mass of the Artemis stack after it reaches LEO but before it lights the engines to head to the Moon.
It is ** that ** mass the Space Tug needs to push.
You also need to add the mass of the docking structure that goes onto the Starship nose.
A section of the top of the first SLS stage is what I think is needed. And that section needs to be welded to the Starship you are modifying for this venture.
A small but important detail is how to mate the base of the Interim Second Stage to the structure added to the Starship's nose.
This has to happen via automation. The docking collar on Drago II is designed to mate automatically with the ISS port.
The "port" to be docked in our Space Tug scenario is 9 meters across or thereabouts. That would be challenging to dock, I would think.
(th)
Offline
Like button can go here
For GW Johnson re Space Tug for Artemis II mission...
I asked Google for help with the diameter of the Interim Upper Stage.... it came back with helpful information.
The stage is only (about) 5 meters across, which is less than the 9 meters of Starship.
The docking ring would fit comfortably inside the hull of the Starship that would serve as a Space Tug.
Search Labs | AI Overview
Learn more
The diameter of the Interim Cryogenic Propulsion Stage (ICPS), the second stage of the SLS rocket, is 5.1 meters.
Explanation: The ICPS is described as having a diameter of 16.7 feet, which converts to 5.1 meters.Key points about the ICPS:
Diameter: 5.1 meters
Height: 13.7 meters
Function: Provides in-space propulsion after the core stage and solid rocket boosters separate
SLS (Space Launch System) Interim Cryogenic Propulsion ...
3 days ago — SLS (Space Launch System) Interim Cryogenic Propulsion Stage - NASA. ... (13.7 m) tall and 16.7 ft. (5.1 m) in diameter,NASA
Space Launch System - Interim Cryogenic Propulsion Stage (ICPS)
Measuring 45 ft (13.7 m) tall and 16.7-foot (5.1 m) in diameter, the ICPS is a single-engine liquid hydrogen/liquid oxygen-based s...NASA (.gov)
NASA: Artemis I
Measuring 45 ft (13.7 m) tall and 16.7-foot (5.1 m) in diameter, the Interim Cryogenic Propulsion Stage is a single-engine liquid ...
NASA.gov
Show all
Show more
SLS (Space Launch System) Interim Cryogenic Propulsion Stage
Measuring 45 ft. (13.7 m) tall and 16.7 ft. (5.1 m) in diameter, the ICPS provides in-space propulsion after the SLS solid rocket boosters and core stage are jettisoned.3 days agoSLS (Space Launch System) Interim Cryogenic Propulsion ...
NASA (.gov)
https://www.nasa.gov › reference › icps
About featured snippets
•
Feedback
People also ask
What is the diameter of the SLS core stage?
What is the fairing diameter of SLS Block 2?
How big is the interim cryogenic propulsion stage?
What is the diameter of the Delta 2 rocket?
FeedbackSpace Launch System Interim Cryogenic Propulsion Stage ...
NASA (.gov)
https://www.nasa.gov › reference › space-launch-syste...
Sep 23, 2023 — Measuring 45 ft (13.7 m) tall and 16.7-foot (5.1 m) in diameter, the ICPS is a single-engine liquid hydrogen/liquid oxygen-based system that ...Space Launch System
Wikipedia
https://en.wikipedia.org › wiki › Space_Launch_System
It is expected to be used by Block 1B and Block 2. The EUS shares the core stage diameter of 8.4 meters, and will be powered by four RL10C-3 engines.Delta Cryogenic Second Stage
Wikipedia
https://en.wikipedia.org › wiki › Delta_Cryogenic_Seco...
For the Delta IV Medium configuration, a tapering interstage was employed to transition between the 5-meter diameter of the first stage and the smaller 4-meter ...SLS Rocket Components for Deep Space Missions
The Boeing Company
https://www.boeing.com › space-launch-system › launch
The Interim Cryogenic Propulsion Stage (ICPS) for SLS Block 1 is the initial ... The cone-shaped adapter is roughly 30 feet (9.1 meters) in diameter by 30 feet ...Second SLS core stage ready to ship to Florida
SpaceNews
https://spacenews.com › second-sls-core-stage-ready-to-...
Jul 17, 2024 — Saturn V first stage was 33 feet in diameter (10 meters), and quite the beast. I'm glad we're getting back to these enormous rockets that ...ICPS-1: Stage stacked atop first SLS rocket
United Launch Alliance
https://blog.ulalaunch.com › blog › icps-1-stage-stacke...
Jul 7, 2021 — Manufactured at ULA's rocket factory in Decatur, Ala., the ICPS is a modified version of the five-meter-diameter Delta Cryogenic Second Stage ( ...NASA Space Launch SYstem
Lunar and Planetary Institute
https://www.lpi.usra.edu › SLS_FactSheet_long
Towering over 200 feet tall with a diameter of 27.5 feet, the core stage will store cryogenic liquid ... based on Boeing's Delta Cryogenic Second Stage used on.
Missing: meters | Show results with: metersICPS-2: ULA-built upper stage arrives for Artemis II launch
United Launch Alliance
https://blog.ulalaunch.com › blog › icps-2-ula-built-up...
Aug 18, 2021 — The ICPS is based on the five-meter-diameter version of ULA's Delta Cryogenic Second Stage (DCSS) that has flown 24 times on Delta IV missions ...By the numbers: The Space Launch System, NASA's next ...
Astronomy Magazine
https://www.astronomy.com › space-exploration › by-t...
Sep 2, 2022 — The 177-feet long boosters are made of five segments that weigh, in total, 1.6 million pounds (725,000 kg). The boosters produce more than 3.2 ...
People also search for
(the)
Offline
Like button can go here