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.
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 %)
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?
"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."
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!
nine_k|1 year ago
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 %)
prox|1 year ago
psd1|1 year ago
bpodgursky|1 year ago
MPSimmons|1 year ago
I really look forward to the heavy-lift future where full reusability means actual cheap spaceflight.
westurner|1 year ago
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?
dpifke|1 year ago
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."
T-A|1 year ago
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