Eagle1Division
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This is a concept I've been on for maybe half a year now, it's a shuttle that works for all the Galilean moons, and with some simple field mods (reflective foil for sun protection, like the foil used on the Apollo landers) also works on Luna. An "Exo-Atmospheric Orbital Transportation Vehicle".
No futuristic technology, just ol'fashioned LOX-LH2 engines, chosen because of the vast abundance of water ice on the Galilean moons, and MMH/N204 OMS engines.
If all goes well, this should be the first part of a series of vessels, followed by a very heavy cis-lunar LOX/LH-2 transport (almost could say cruise liner), and a similar vessel using VASIMR drives for Jupiter's cislunar space.
Anyways, it's very early and somewhat ugly in terms of appearance, but we're orbinauts, it's the thought behind the vessel that counts
And pictures speak 1,000 words, cliche' but true.
I'll divide this into 4 sections, Overview, Engines, Cabin, and Mission.
OTV Overview:
Mission: Orbital lift/transport
Bodies of operation:
Luna (Moon)
Ganymede
Callisto
Europa
Io (Extra radiation shielding req.)
Normal crew: 4
Maximum crew: 7
Payload: 70,000 kg
Vehicle weight: 60,000 kg
Full Payload Takeoff weight: 352,400 kg
Total Delta-Vee: ~4,887.7 m/s
Mass Ratio:
(As per mass of empty vehicle+payload)
1.27 MMH/N204
2.44 LOX/LH-2
Engines:
1x Main Engine, 2x Rotary Main Engines (RME's):
Propellant: LOX/LH2
Thrust: 1,235.3 kN each
ISP: 460 seconds
2x OME:
Propellant: MMH/N204
Thrust: 422.5 kN each
ISP: 370 seconds
1x Retro/Hover
Propellant: MMH/N204
Thrust: 659.7 kN
ISP: 370 seconds
Space shuttle orbiter (missing it's OMS RCS pods and OME's...) in the background for size comparison.
No payload bay doors needed with no atmosphere, it's designed to lift 70 tons, the vehicle itself weighs about as much.
On the nose is the retro engine and an RCS nose assembly.
Behind it is a cabin, with 18 days' endurance with a crew of 7. The OTV can handle 7 crew, but normally operates with 4, a Commander, a Pilot, Flight Engineer and Navigator.
In blue are the LOX tanks, in red are the LH2 tanks for the EPS, 3x the mass of the Space Shuttle's EDO package, for 18 days of power from it's 3 fuel cells.
Behind it is the payload track. A strong support beam to handle the weight of the vehicle under it's peak acceleration of 3 G, and to anchor the payload onto. Above is the robotic arm and radiator.
The four spherical tanks are two MMH and two N204 tanks. This is the earlier design where the retro engine uses the OMS MMH/N204 propellant. I'm thinking of revising the design so that it uses LOX-LH2...
Behind that is the LOX/LH2 tank.
And finally, on the very back end are the three main engines, and, not yet modeled, the two OME's, APU's, and RCS units.
Cabin notes:
This is from later on, and a lot of stuff is still WIP. Notice the hatch is more like the cabin door on a pressurized airliner (50,000 feet altitude has same physiological effects as space), and the little red box next to it is sort of mini cupola for a quick visual examination of the area immediately around the airlock door before going through it.
Engines:
At the very front is the Retro engine, this, along with the lower two rear RMEs, allows the vehicle to hover. The three LOX-LH2 engines on the rear form a triangle like the STS, but the bottom two are different:
A roller and a track allow them to rotate 90* downwards, along with the nose engine doing the same, this allows the vehicle to hover for liftoff and landing. Shown here is an RME. The track allows 90* of rotation, gimballing provides a further 12* in any direction.
Cabin:
Pink: Flight Deck
(STS FD is temporary drop-in, actual flight deck will be different)
Green: Living space
(Sleeping bags, personal items, kitchennete, etc.)
Red: Airlock
Orange: RMS control station
Blue: Lavratory
(I almost forgot this bit...)
Light Blue (on bottom): Crawlspace
(Allows access to ECLSS N2, O2 and all water tanks without an EVA)
The red circle is an overhead window for the docking control station. All the windows have covers similar to the covers on the ISS's Cupola, to protect from micrometeorite damage, so the windows don't have to be replaced nearly as often. Sapphire windows are expensive!
(Other windows not modeled yet)
Typical Mission:
Normal crew: 4
Maximum crew: 7
Payload: 70,000 kg
Vehicle weight: 60,000 kg
Full Payload Takeoff weight: 352,400 kg
Tankage:
187,413 kg LOX/LH2
34,986 kg MMH/N204
Body: Callisto
Pre-Ignition:
Vehicle is loaded, fueled, and prepped to launch. APU's, EPS, ECLSS, and other vehicle systems are all started and running. APU's are set to HIGH mode, draining twice the fuel as normal to generate the power necessary to rotate the 2 main engines and hover engine while they're under power.
The 2 rotary main engines and hover engine are rotated downwards.
Vertical Ascent:
The two rotary main engines are ignite at a sub-liftoff throttle. Once ignition is confirmed, and engines are ready for throttle-up, the forward MMH/N204 engine ignites and all are throttled-up in sync for liftoff. The vehicle accelerates upwards at 2.5 m/s^2.
While accelerating upwards, "Yaw Program" is initiated and the vehicle Yaws by RCS to the launch heading. Once ~100 m/s of vertical velocity is achieved (gravitational drag for the 114 second ride to orbit), the two rotary main engines throttle down and rotate back to horizontal over the course of 7 seconds, putting the vehicle into the "Horizontal Ascent" mode.
Horizontal Ascent:
The center main engine is ignited and throttled-up simultaneously with the two rotary main engines, once they are in position. The APU is set to NORM mode, now consuming 1 kg of LOX+LH2 per minute, now that the rotary engines are in horizontal.
The vehicle accelerates with a pitch of 0*, so that it's vertical velocity is ~0 m/s once it reaches orbital velocity, at an altitude of ~5 km. Slight pitch adjustments may be used by the GNC to achieve this, there is enough Delta-Vee for a tolerance of 5* off-center pitch. Engine will continue burning until Apoapsis is at ~250 km (standard minimal), or whatever mission orbit altitude is required.
Post-MECO:
Retro/hover engine rotated back to horizontal for on-orbit ops. Radiator and antenna deployed, and the OMS puts the vehicle on proper course. MPS system is purged, and APU's are set to LOW until near the OME burn, when they'll be set to NORM, then shut off once OMS-2 is complete. OMS-2 burn is always required for orbit circulization.
On-Orbit:
The OMS system has:
25 m/s allocated to orbit circulization
32 m/s allocated to the climb to 250 km
143 m/s allocated to plane alignment burns (~5.4* degrees) (Note: almost all orbits are equatorial over Galilean moons.)
50 m/s allocated to free maneuvering/course adjustment
25 m/s allocated to RCS
40 m/s allocated to de-circulizing the orbit prior to Powered Descent.
Powered Descent:
APU's are restarted and set to HIGH, MPS system purged prior to ignition. Radiators, RMS, and antenna are stored. The OME's drop the orbit periapsis to 3-5 km over the landing site, and the retro/hover engine rotates to 90* vertical. At a predetermined distance from the landing site (For Callisto, this is 77,612 meters), the 3 main engines are ignited, and the vehicle decelerates to full-stop 3-5 km over the landing site within a certain minimum radius from the pad. Center engine is CO, and the two RMEs rotate to 90* with a synchronized ignition and throttle-up with the forward hovering engine, entering the "Final Approach" phase of the flight.
Final Approach:
For Callisto, the pilot has 200 seconds of hover time and 90 m/s of reserve OMS propellant set aside for the final approach. The autopilot can land with far less, but this propellant is set aside for manual approach, should it be necessary. Once the vehicle touches down, all engines are CO, APU's are shut down, and the MPS is purged. EPS is set to low-power mode to keep the stored vehicle interior human-survivable, even if it is not occupied.
So far I'm thinking of changing the forward hover engine to use LOX/LH2, so if it runs out, it'll happen at the same time as the rotary main engines. Also I might increase the MMH/N204 amount to allow for more mission flexibility, which would also require increasing the amount of LOX/LH-2 to support it. But the mass ratio is below 3, even, so I'd think it still makes sense. Of course that would mean a ~5-second ignition and less reliability, but a more fuel efficient engine.
The APU's run on LOX/LH2 because hydrazine would require even more facilities to synthesize on the Galilean moons, I want to use LOX/LH-2 as much as possible since that can simply be extracted from the abundant water ice. Also, consuming only 1 kg a minute (the STS APU's consume 2 kg / minute, IIRC, of hydrazine. And they also must power the flight surfaces, which the OTV doesn't need to...), the APU fuel tanks can easily be refuelled from the main engine's propellant tank (Which has 187,413 kg...). There is a certain contingency amount of propellant, and the payload is very rarely going to be a full 70 tons, so if you need more APU fuel for whatever reason, there's plenty in the Main Engine's propellant tank for cross-feeding.
(APU fuel tank holds 75 kg, for a bit more than an hour of operation at NORM, and half an hour at HIGH. Ascent lasts 154 seconds, descent lasts a maximum of ~300 seconds)
No futuristic technology, just ol'fashioned LOX-LH2 engines, chosen because of the vast abundance of water ice on the Galilean moons, and MMH/N204 OMS engines.
If all goes well, this should be the first part of a series of vessels, followed by a very heavy cis-lunar LOX/LH-2 transport (almost could say cruise liner), and a similar vessel using VASIMR drives for Jupiter's cislunar space.
Anyways, it's very early and somewhat ugly in terms of appearance, but we're orbinauts, it's the thought behind the vessel that counts
And pictures speak 1,000 words, cliche' but true.
I'll divide this into 4 sections, Overview, Engines, Cabin, and Mission.
OTV Overview:
Mission: Orbital lift/transport
Bodies of operation:
Luna (Moon)
Ganymede
Callisto
Europa
Io (Extra radiation shielding req.)
Normal crew: 4
Maximum crew: 7
Payload: 70,000 kg
Vehicle weight: 60,000 kg
Full Payload Takeoff weight: 352,400 kg
Total Delta-Vee: ~4,887.7 m/s
Mass Ratio:
(As per mass of empty vehicle+payload)
1.27 MMH/N204
2.44 LOX/LH-2
Engines:
1x Main Engine, 2x Rotary Main Engines (RME's):
Propellant: LOX/LH2
Thrust: 1,235.3 kN each
ISP: 460 seconds
2x OME:
Propellant: MMH/N204
Thrust: 422.5 kN each
ISP: 370 seconds
1x Retro/Hover
Propellant: MMH/N204
Thrust: 659.7 kN
ISP: 370 seconds
Space shuttle orbiter (missing it's OMS RCS pods and OME's...) in the background for size comparison.
No payload bay doors needed with no atmosphere, it's designed to lift 70 tons, the vehicle itself weighs about as much.
On the nose is the retro engine and an RCS nose assembly.
Behind it is a cabin, with 18 days' endurance with a crew of 7. The OTV can handle 7 crew, but normally operates with 4, a Commander, a Pilot, Flight Engineer and Navigator.
In blue are the LOX tanks, in red are the LH2 tanks for the EPS, 3x the mass of the Space Shuttle's EDO package, for 18 days of power from it's 3 fuel cells.
Behind it is the payload track. A strong support beam to handle the weight of the vehicle under it's peak acceleration of 3 G, and to anchor the payload onto. Above is the robotic arm and radiator.
The four spherical tanks are two MMH and two N204 tanks. This is the earlier design where the retro engine uses the OMS MMH/N204 propellant. I'm thinking of revising the design so that it uses LOX-LH2...
Behind that is the LOX/LH2 tank.
And finally, on the very back end are the three main engines, and, not yet modeled, the two OME's, APU's, and RCS units.
Cabin notes:
This is from later on, and a lot of stuff is still WIP. Notice the hatch is more like the cabin door on a pressurized airliner (50,000 feet altitude has same physiological effects as space), and the little red box next to it is sort of mini cupola for a quick visual examination of the area immediately around the airlock door before going through it.
Engines:
At the very front is the Retro engine, this, along with the lower two rear RMEs, allows the vehicle to hover. The three LOX-LH2 engines on the rear form a triangle like the STS, but the bottom two are different:
A roller and a track allow them to rotate 90* downwards, along with the nose engine doing the same, this allows the vehicle to hover for liftoff and landing. Shown here is an RME. The track allows 90* of rotation, gimballing provides a further 12* in any direction.
Cabin:
Pink: Flight Deck
(STS FD is temporary drop-in, actual flight deck will be different)
Green: Living space
(Sleeping bags, personal items, kitchennete, etc.)
Red: Airlock
Orange: RMS control station
Blue: Lavratory
(I almost forgot this bit...)
Light Blue (on bottom): Crawlspace
(Allows access to ECLSS N2, O2 and all water tanks without an EVA)
The red circle is an overhead window for the docking control station. All the windows have covers similar to the covers on the ISS's Cupola, to protect from micrometeorite damage, so the windows don't have to be replaced nearly as often. Sapphire windows are expensive!
(Other windows not modeled yet)
Typical Mission:
Normal crew: 4
Maximum crew: 7
Payload: 70,000 kg
Vehicle weight: 60,000 kg
Full Payload Takeoff weight: 352,400 kg
Tankage:
187,413 kg LOX/LH2
34,986 kg MMH/N204
Body: Callisto
Pre-Ignition:
Vehicle is loaded, fueled, and prepped to launch. APU's, EPS, ECLSS, and other vehicle systems are all started and running. APU's are set to HIGH mode, draining twice the fuel as normal to generate the power necessary to rotate the 2 main engines and hover engine while they're under power.
The 2 rotary main engines and hover engine are rotated downwards.
Vertical Ascent:
The two rotary main engines are ignite at a sub-liftoff throttle. Once ignition is confirmed, and engines are ready for throttle-up, the forward MMH/N204 engine ignites and all are throttled-up in sync for liftoff. The vehicle accelerates upwards at 2.5 m/s^2.
While accelerating upwards, "Yaw Program" is initiated and the vehicle Yaws by RCS to the launch heading. Once ~100 m/s of vertical velocity is achieved (gravitational drag for the 114 second ride to orbit), the two rotary main engines throttle down and rotate back to horizontal over the course of 7 seconds, putting the vehicle into the "Horizontal Ascent" mode.
Horizontal Ascent:
The center main engine is ignited and throttled-up simultaneously with the two rotary main engines, once they are in position. The APU is set to NORM mode, now consuming 1 kg of LOX+LH2 per minute, now that the rotary engines are in horizontal.
The vehicle accelerates with a pitch of 0*, so that it's vertical velocity is ~0 m/s once it reaches orbital velocity, at an altitude of ~5 km. Slight pitch adjustments may be used by the GNC to achieve this, there is enough Delta-Vee for a tolerance of 5* off-center pitch. Engine will continue burning until Apoapsis is at ~250 km (standard minimal), or whatever mission orbit altitude is required.
Post-MECO:
Retro/hover engine rotated back to horizontal for on-orbit ops. Radiator and antenna deployed, and the OMS puts the vehicle on proper course. MPS system is purged, and APU's are set to LOW until near the OME burn, when they'll be set to NORM, then shut off once OMS-2 is complete. OMS-2 burn is always required for orbit circulization.
On-Orbit:
The OMS system has:
25 m/s allocated to orbit circulization
32 m/s allocated to the climb to 250 km
143 m/s allocated to plane alignment burns (~5.4* degrees) (Note: almost all orbits are equatorial over Galilean moons.)
50 m/s allocated to free maneuvering/course adjustment
25 m/s allocated to RCS
40 m/s allocated to de-circulizing the orbit prior to Powered Descent.
Powered Descent:
APU's are restarted and set to HIGH, MPS system purged prior to ignition. Radiators, RMS, and antenna are stored. The OME's drop the orbit periapsis to 3-5 km over the landing site, and the retro/hover engine rotates to 90* vertical. At a predetermined distance from the landing site (For Callisto, this is 77,612 meters), the 3 main engines are ignited, and the vehicle decelerates to full-stop 3-5 km over the landing site within a certain minimum radius from the pad. Center engine is CO, and the two RMEs rotate to 90* with a synchronized ignition and throttle-up with the forward hovering engine, entering the "Final Approach" phase of the flight.
Final Approach:
For Callisto, the pilot has 200 seconds of hover time and 90 m/s of reserve OMS propellant set aside for the final approach. The autopilot can land with far less, but this propellant is set aside for manual approach, should it be necessary. Once the vehicle touches down, all engines are CO, APU's are shut down, and the MPS is purged. EPS is set to low-power mode to keep the stored vehicle interior human-survivable, even if it is not occupied.
So far I'm thinking of changing the forward hover engine to use LOX/LH2, so if it runs out, it'll happen at the same time as the rotary main engines. Also I might increase the MMH/N204 amount to allow for more mission flexibility, which would also require increasing the amount of LOX/LH-2 to support it. But the mass ratio is below 3, even, so I'd think it still makes sense. Of course that would mean a ~5-second ignition and less reliability, but a more fuel efficient engine.
The APU's run on LOX/LH2 because hydrazine would require even more facilities to synthesize on the Galilean moons, I want to use LOX/LH-2 as much as possible since that can simply be extracted from the abundant water ice. Also, consuming only 1 kg a minute (the STS APU's consume 2 kg / minute, IIRC, of hydrazine. And they also must power the flight surfaces, which the OTV doesn't need to...), the APU fuel tanks can easily be refuelled from the main engine's propellant tank (Which has 187,413 kg...). There is a certain contingency amount of propellant, and the payload is very rarely going to be a full 70 tons, so if you need more APU fuel for whatever reason, there's plenty in the Main Engine's propellant tank for cross-feeding.
(APU fuel tank holds 75 kg, for a bit more than an hour of operation at NORM, and half an hour at HIGH. Ascent lasts 154 seconds, descent lasts a maximum of ~300 seconds)
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