NASA, Axiom Space Change Assembly Order of Commercial Space Station | Hacker News Reader

NASA, Axiom Space Change Assembly Order of Commercial Space Station

nasa.gov

94 pointsmzs42 comments

I wonder if there's any useful heavy equipment aboard the ISS that could be transferred to the Axiom prior to separation and thus salvaged. It'd have to be stuff the ISS could do without for the remaining couple years of its life.

Something like Canadarm?

I suppose ISS is being decommissioned in a big part because the big hardware there is approaching / has approached the end of its practical life. The metal has accumulated fatigue here and there. The solar panels are heavy and inefficient, compared to more modern developments, except for the newest array mounted in 2021.

Maybe some of the newest hardware could be transferred to a lower orbit for cheaper than bringing up brand new hardware from Earth.

The thing is that the newest ISS modules, barely 4 years old, are Russian (Nauka + Prichal); the newest module before that is the Japanese science module from 2008. It could probably be still reused, it's barely 16 years old %)

Or just ship of Theseus it? Replace what needs replacement into he new format?

Likely the only things that would remain then would be the interfaces and standards. On one hand, these are time-tested standards. OTOH perpetuating them would miss an opportunity to evolve and upgrade, fixing some of the known issues.

Isn't that happening anyway? New stations will be designed to interface with current spacecraft, that are designed to interface with current space stations.

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Maybe but to be honest Starship cost-per-pound to LEO will make re-use of 20 year old technology, in questionable states of maintenance, less appealing than starting from a clean slate in most cases.

Agreed. When it comes to flying people, the volume of a habitable starship is approximately equivalent to the entirety of the habitable volume of the ISS.

I really look forward to the heavy-lift future where full reusability means actual cheap spaceflight.

I wonder if the ISS could instead be scrapped to the moon.

Let's get this space station to the moon.

Can a [Falcon 9 [Heavy] or similar] rocket shove the ISS from its current attitude into an Earth-Moon orbit with or without orbital refuelling?

The ISS weighs 900,000 lbs on Earth.

Have we yet altered the orbital trajectory of anything that heavy in space?

Can any existing rocket program rendezvous and boost sideways to alter the trajectory of NEOs (Near-Earth Objects) or aging, heirloom, defunct space stations?

Which of the things of ISS that we have internationally paid to loft into orbit would be useful for future robot, human, and emergency operations on the Moon?

NASA evaluated a bunch of options before deciding to de-orbit ISS. You can read a summary here: https://www.nasa.gov/wp-content/uploads/2024/06/iss-deorbit-... (PDF)

About boosting to a higher orbit, they wrote:

"Space station operations require a full-time crew to operate, and as such, an inability to keep crews onboard would rule out operating at higher altitudes. The cargo and crew vehicles that service the space station are designed and optimized for its current 257 mile (415km) altitude and, while the ability of these vehicles varies, NASA’s ability to maintain crew on the space station at significantly higher altitudes would be severely impacted or even impossible with the current fleet. This includes the International crew and cargo fleet, as Russian assets providing propulsion and attitude control need to remain operational through the boost phase.

"Ignoring the requirement of keeping crew onboard, NASA evaluated orbits above the present orbital regime that could extend just the orbital lifetime of the space station. [...]

"However, ascending to these orbits would require the development of new propulsive and tanker vehicles that do not currently exist. While still currently in development, vehicles such as the SpaceX Starship are being designed to deliver significant amounts of cargo to these orbits; however, there are prohibitive engineering challenges with docking such a large vehicle to the space station and being able to use its thrusters while remaining within space station structural margins. Other vehicles would require both new certifications to fly at higher altitudes and multiple flights to deliver propellant.

"The other major consideration when going to a higher altitude is the orbital debris regime at each specified locale. The risk of a penetrating or catastrophic impact to space station (i.e., that could fragment the vehicle) increases drastically above 257miles (415km). While higher altitudes provide a longer theoretical orbital life, the mean time between an impact event decreases from ~51 years at the current operational altitude to less than four years at a 497 mile (800km), ~700-year orbit. This means that the likelihood of an impact leaving station unable to maneuver or react to future threats, or even a significant impact resulting in complete fragmentation, is unacceptably high. NASA has estimated that such an impact could permanently degrade or even eliminate access to LEO for centuries."

Thanks for the research.

How are any lunar orbital trajectories relatively safe given the same risks to all crafts at such altitudes?

Is it mass or thrust, or failure to plan something better than inconsiderately decommissioning into the atmosphere and ocean.

If there are escape windows to the moon for other programs, how are there no escape windows to the moon for the ISS?

Given the standing risks of existing orbital debris and higher-altitude orbits' lack of shielding, are NEO impact collisions with e.g. hypersonic glide delivery vehicles advisable methods for NEO avoidance?

The NEO avoidance need is still to safely rendezvous and shove things headed for earth orbit into a different trajectory;

Is there a better plan than blowing a NEO up into fragments still headed for earth, like rendezvousing and shoving to the side?

m_ISS ~ 4.5e5 kg [1]

Rocket equation [2]:

m_0 = m_f exp(v_delta / v_e)

where

m_f = final mass, i.e. mass of ISS and the boosters

m_0 = m_f + propellant mass

v_delta = velocity change

v_e = effective exhaust velocity of the boosters

Let's try a high-thrust transfer from LEO to the Lunar Gateway's orbit via TLI (Trans-Lunar Injection) [3]:

v_delta = 3.20 + 0.43 = 3.63 km/s

For boosters, let's use the dual-engine Centaur III (because Wikipedia has mass and v_e data for it) [4]:

m_dry = 2462 kg

m_propellant = 20830 kg

v_e = 4.418 km/s

The idea is to attach n of these to the ISS. The rocket equation becomes

m_ISS + n (m_dry + m_propellant) = (m_ISS + n m_dry) exp(v_delta / v_e)

Solve for n:

n = m_ISS (exp(v_delta / v_e) - 1) / (m_propellant + m_dry (1 - exp(v_delta / v_e)) )

Plug in numbers and find

n ~ 32.4

So we need 33 Centaur III (and some way to attach them, which I optimistically assume won't add significantly to the ISS mass).

Total Centaur III + propellant mass: 33 * (2462 + 20830) = 768636 kg

Planned Starship payload capacity to LEO is 2e5 kg [5], so assuming that a way can be found to fit 7 Centaur III in its payload bay, we can get all 33 boosters to LEO with five Starship launches.

Why not use Starship itself? Its Raptor Vacuum engines have lower v_e (~3.7 km/s) [6], and if you want it back, you need to add fuel for the return trip to m_f. Exercise for the reader!

[1] https://en.wikipedia.org/wiki/International_Space_Station

[2] https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

[3] https://en.wikipedia.org/wiki/Delta-v_budget#Earth_Lunar_Gat...

[4] https://en.wikipedia.org/wiki/Centaur_(rocket_stage)

[5] https://en.wikipedia.org/wiki/SpaceX_Starship_(spacecraft)

[6] https://en.wikipedia.org/wiki/SpaceX_Raptor#Raptor_Vacuum

Thanks for the numbers. I think it's still possible to create gists with .ipynb Jupyter notebooks which have can have latex math and code with test assertions; symbolic algebra with sympy, astropy, GIZMO-public, spiceypy

> and some way to attach them

Because of my love for old kitchens on the Moon.

(The cost then to put all of that into orbit, in today's dollars)

So, orbitally refuelling Starship(s) would be less efficient than 33 of the cited capability all at once.

This list is pretty short:

Template:Engine_thrust_to_weight_table: https://en.wikipedia.org/wiki/Template:Engine_thrust_to_weig...

What about solar; could any solar-powered thrusters - given an unlimited amount of time - shove the ISS into a dangerous orbit towards the moon instead of the ocean?

> and some way to attach them

There's a laser welding in space spec and grants FWIU.

Can any space program do robotic spacecraft hull repair in orbit, like R2D2? With laser welding?

Or do we need to find more people like Col. McBride in brad pitt space movie, more astronauts?

Is the task to fabricate a 3d mount to attach a gradual thrust mechanism to a NEO?

> sympy, astropy, GIZMO-public, spiceypy

poliastro

Why is the ISS not being privatized or boosted into a higher orbit for possible later use?

It's not being privatized because it's extremely expensive to maintain and also it's politically impossible as several modules are Japanese or European owned and half the station is Russian and there's no propulsion on the USOS side.

As to not boosting it to a higher orbit, firstly that would require a tremendous amount of energy, more than any craft currently visiting it. So you'd need to custom build something for that purpose. They're already custom building something to deorbit it with less thrust requirements than you'd need to boost it upward. Secondly the station is slowly experiencing cracking and eventually will suffer a catastrophic debris strike or depressurization. This massive object would create a massive debris cloud and putting it in a high orbit would ensure it would last for thousands of years.

ISS is being replaced by one or more semi-privatized stations. ISS is rapidly approaching the point where maintaining it costs more than simply building a new station.

Not a dumb question, official answers in [1] [2].

Summary is higher orbits have too much risk of debris strikes, and commercial operators were asked to submit proposals but NASA received no feasible proposal: they aren't interested in the ageing and expensive to maintain ISS modules.

[1] https://www.nasa.gov/wp-content/uploads/2024/06/iss-deorbit-...

[2] https://www.nasa.gov/faqs-the-international-space-station-tr...

It would be cool if we could at least park it for a few years until we can bring it back down in Starships.

Maybe Bezos would help fund those missions, even if they used Starship…

It's old and expensive. For example, there's a 5 year old leak that they still can't locate or even decide on the severity.

I'm sure the offer is open if anyone wants it, but that's a hard sell at this point, and the major players all have other plans.

https://spacenews.com/nasa-and-roscosmos-disagree-on-cause-a...

There's also a political factor for why it's not being boosted, in that as long as the ISS exists governments and the public would want to see it maintained and used. Just boosting it and letting it rot would make space agencies look really bad in the eyes of the public. It's better to just decommission it and have no chance of a future salvage effort. (this doesn't touch on why not do privatization of the ISS, other comments have responded)

It is slowly becoming unsafe, and fixing it in orbit is likely too expensive. Space is a very punishing environment - enormous differences in temperature, vacuum, aggressive radiation. 25 years of such conditions will have consequences.

It could probably be dragged onto a higher orbit as a museum in situ, but keeping actual living people in there is going to become too risky soon.

I am guessing that:

Space Station AMS-02 Instrument Works on the Mystery of Dark Matter

https://www.nasa.gov/image-article/space-station-ams-02-inst...

Is coming to its end of life too

As a CERN experiment it seems to have produced a lot of science:

https://www.nasa.gov/image-article/space-station-ams-02-inst...

NASA's next space station will be in lunar orbit:

https://www.nasa.gov/mission/gateway/

This isn’t a normal useful orbit in terms of supporting astronauts on the moon or being available for recovery etc. and was definitely not used to support earlier moon landings. I think it only has a lunar revisit once every 7 days. Imagine your abort / recovery to orbit option is only available for this one tiny window.

SLS probably can’t get Orion to Lunar orbit unfortunately so they have created this insanely costly / complex / lower utility approach.

About orbits: https://news.ycombinator.com/item?id=42538057

It's surprising to see that every comment's angle is spreading Musk's stories, trashing his competition, etc.

It's worth mentioning that Gateway is on the cutting block if the likely SLS cancellation happens during this incoming administration. As the entire reason for Gateway existing and being where it is is to act as a destination for SLS before the moon landing program was announced. It is where it is because of the relatively weak performance specifications of the SLS rocket preventing it from launching the Orion spacecraft into a low lunar orbit. SLS was also destined to launch several of the Gateway modules which would be impossible if its canceled.

Yes I could see deals being worked out where gateway partners instead build parts of a lunar base. The international partnerships a likely the biggest piece going for gateway in terms of not being cancelled

It seems to me that if SLS goes… so does Gateway. That said, one thing to note: There are not that many stable lunar orbits. Unlike the earth, the moon is very lumpy. It is the reason why most lunar orbiters end up doing a planned crash as their end of (relatively) short life. From that standpoint, orbits that are a bit further out are much more appealing to have relatively low delta v requirements.

All that said, once Starship is regularly in use for lunar delivery… I suspect we will have a fundamental new paradigm for space.

There are low lunar orbit frozen orbits that don't do that.

> As the entire reason for Gateway existing and being where it is is to act as a destination for SLS

I don't think that's true. I've long heard of it as support for surface operations and for preparation (R&D, etc.) for Mars.

"A space station" is desireable. The lunar gateway, though, as designed, is very much about Artemis. The Near Rectilinear Halo Orbit[1] was designated because of constraints on the Orion capsule that will be attached during crewed operations, at least this was relayed to me directly by NASA personnel during a Q&A.

[1] - https://en.wikipedia.org/wiki/Near-rectilinear_halo_orbit

It has more to do with reducing propellant needed for station keeping. NRHO is useful for lunar fuel depots.

One of the goals of gateway is to act as a test bed for long term manned operations outside of low earth orbit. I.e. start developing and proving the technology in flight that we are going to need for a mars mission.

The conops for this doesn’t make sense to me. Not only is it in a weird orbit but after the first lunar landing, which will have two astronauts, the rest will have four. With all 4 crew members on the lunar surface who will be working on gateway? SLS can max launch once a year. Are we really going to give up a lunar landing opportunity for a gateway only mission? Already 1 mission a year for a couple weeks is a big change from a quarter century of continuous operations on ISS. Mix of commercial space stations in LEO supported by regular NASA crews and lunar mission with eventual base seems the most inspiring and beneficial way to keep consistent presence in space was explaining exploration and building private space capability/infrastructure.

It might be interesting to look up Gateway's mission and see why they are putting it in in orbit around the Moon rather than Earth. I know a major part of it is to learn the lessons needed for a human trip to Mars.

> Not only is it in a weird orbit

Regarding lunar orbits (I don't know about Gateway's orbit):

We are used to relatively stable gravity in Earth orbit, but it is much different out near the Moon: Gravity in cislunar space creates chaotic trajectories due to the three-body problem of Earth, Moon, and the vehicle. Orbits around the Moon are also much less stable than around Earth. There are only a few stable orbits, all below 700 km.

Here's a pretty good resource:

https://www.afrl.af.mil/Portals/90/Documents/RV/A%20Primer%2...

I assume SLS’s shelf life is limited and we’ll be using Starship end to end within 5 years or so.

  >With all 4 crew members on the lunar surface who will be working on gateway?

One of the technology advancements being pushed by Gateway is that (unlike ISS) it wouldn't require a constant human presence.

reminds me of the space liner from walle - they should add a mcdonalds module to it that is fully automated. just as a marketing campaign to be first autonomous fast food chain in space on the axiom… also for good meme content

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