{snip}For the second and third options, we can assume that the reusable lander is operating out of a Lunar Orbital station or Depot staging point. For the expendable option, a Lunar space station is not strictly needed. Such a vehicle depending on the exact configuration and propulsion design, could mass anywhere between 25 and more than 30 metric tons.
If ITS, New Armstrong or some equivalent happens, you might not need to service it in space. If the lander could be made to fit in a reusable vehicle's cargo area, you could cycle it back to Earth for maintenance.
Quote from: Space Core on 02/13/2017 02:46 amIf ITS, New Armstrong or some equivalent happens, you might not need to service it in space. If the lander could be made to fit in a reusable vehicle's cargo area, you could cycle it back to Earth for maintenance.Errr, if ITS is possible, then why would you need a separate lunar lander? ITS would be the reusable, refuellable lunar lander.
If a thruster malfunctioned, then you'd remove the thruster assembly and swap in a spare. T
Would X-ray scanning cubesats circling about help?
Quote from: Jim on 07/14/2017 05:22 pmQuote from: Propylox on 07/13/2017 11:04 pm Would X-ray scanning cubesats circling about help? No, because we can't even do that type of diagnostic test on earth with complex metallic systems.What about "non-complex"? My specific concerns are the propellant lines from powerhead to combustion chambers on the OME and main engine, as well as fatigue in the metal and/or composite structural beams (there's vibration and torsional stress). Is inspecting worth the hassle, of just estimate lifecycle and scrap when approaching it.
Quote from: Propylox on 07/13/2017 11:04 pm Would X-ray scanning cubesats circling about help? No, because we can't even do that type of diagnostic test on earth with complex metallic systems.
You could build the vehicle with modular assemblies locked into a frame-like chassis, sort of like boards in a computer case. The assemblies would be designed as much as is possible to fit through a standard docking hatch. If a thruster malfunctioned, then you'd remove the thruster assembly and swap in a spare. The faulty assembly could then be returned to Earth for repair. As most of the parts would be designed to fit through hatches used on spacecraft, it might be eventually possible to set up a repair module on either the ISS or a lunar base so that the more simple repairs could be done on site without cycling parts through Earth's gravity well. If you designed it with expansion in mind, it might even be possible to link different assemblies together or even vehicles to provide more processing power or thrust for bigger jobs without having to design and test a new vehicle.
My personal opinion about how astronauts will refurbish some sort of reusable LEM is that they will use a sort of "space garage" in low moon orbit. The mission would likely go something like this- CSM lifts off, and heads to the moon unencumbered. It than rendezvous with a small station that basically just has a hub, a area for refurbishing the LEM, and a docking port. So anyway, they go to the pressurized area that is essentially a large airlock. They refurbish the LEM unencumbered, and depressurize the airlock and take the LEM down to the lunar surface. They then head up, dock with the station, and head home. Just my two pence.
Propellants are high fire risk and can be poisonousness, so the landers will be kept in vacuum. Reusable landers will have to be designed to permit the replacement of rocket engines and legs using robotic arms. The major components will have to be screwed together rather than welded. Although welding can be used within a component.
Quote from: A_M_Swallow on 07/27/2017 03:46 amPropellants are high fire risk and can be poisonousness, so the landers will be kept in vacuum. Reusable landers will have to be designed to permit the replacement of rocket engines and legs using robotic arms. The major components will have to be screwed together rather than welded. Although welding can be used within a component.The fuel would be removed from the lander before the Garage is pressurised.