Quote from: guru on 10/30/2010 05:23 am I don't like putting technology development programs on the critical path to a mission, but atmospheric ISRU, in spite of it low TRL, is still comparatively simple and will be required for any sane Mars mission anyway. There is no need to have the initial missions rely on ISRU as part of their critical path. Also, why sniff for methane when there is water in the soil practically everywhere that could be converted to high Isp LH2/LO2?
I don't like putting technology development programs on the critical path to a mission, but atmospheric ISRU, in spite of it low TRL, is still comparatively simple and will be required for any sane Mars mission anyway.
Because CO2 is available literally everywhere on the surface and can be very easily processed with no scoops or shovels or rovers.
Quote from: Robotbeat on 10/30/2010 11:58 pmBecause CO2 is available literally everywhere on the surface and can be very easily processed with no scoops or shovels or rovers.*sigh*I loove how space cadets armwave engineering challenges away.Did you bother to take a quick look at the presentations i linked to in the thread?
I actually think carbon monoxide may be a superior ISRU fuel on Mars because of its ubiquity and simplicity, but the engine technology needs more development.
Quote from: Robotbeat on 10/31/2010 04:38 amI actually think carbon monoxide may be a superior ISRU fuel on Mars because of its ubiquity and simplicity, but the engine technology needs more development.Yeah, CO/LOX is greatly undervalued vs. CH4/LOX. Even if the engines burn a little hot (and the exhaust products are a little on the heavy side), you at least don't have to bring any of your reaction mass from earth (and it's not exactly difficult to find CO2 on Mars).
If ISRU is a non-starter:1) It would only take 2 extra D-IVH launches, each with a rover/tanker carrying < 650kg of propellant to top up the half MAVs which wouldn't need the ISRU or H2 feedstock and could carry some of their own propellant. 2) Possibly both stages could then use LOX / CH4 or maybe even hypergolics.
Instead of one 90kg astronaut, why not 2 x 45 kg astronauts? (e.g. small women)Instead of launching the surface habitat capsule back to Mars orbit, why not have the crew ride in the open in EVA suits? In fact with two crew, one could ride on each half MAV. Without the capsule, each person could be a little heavier and carry more samples.With SLS, I think you could probably add a Bigelow Sundancer module, with some extra PMs.
The carbon dioxide (CO2) that makes up 95 percent of the atmosphere of Mars can be a valuable starting material for the manufacture of critical products. Unlike lunar resources, CO2 can be had by merely compressing the atmosphere. Carbon dioxide itself can be used to support plant growth at an advanced outpost. Both carbon and oxygen are important elements which have many possible uses at an outpost. There are several well understood chemical reactions that we can use to produce oxygen, methane, water, and perhaps other materials.Oxygen can be produced by passing CO2 through a zirconia electrolysis cell at 800 to 1000deg C. Twenty to thirty percent of the CO2 dissociates into oxygen and carbon monoxide. Separation is accomplished by electrochemical transport of oxide ion through a membrane. A prototype reactor using this chemistry has been run for over 1000 hours. Using such a scheme, we could bring a small unit to the surface of Mars which would then continuously make oxygen for life support, propellant use, or further processing. The only additional item we would need to supply is the power to run it: a 12kW unit would produce about one metric ton of oxygen per month.
Almost every single combustion engine on Earth is doing atmospheric ISRU. Think about that.ISRU is feasible if done properly. It may not be "easy," yet nothing is easy off-world.
I should note that the 12kW example unit would also produce about 2 tons of CO (although not wholly separated) "for free."And regarding RTGs, it's not very feasible for advanced RTGs to have a specific power greater than about 10W/kg(based on info here), whereas it may be possible to deploy a very lightweight solar array that could approach and even surpass that specific power (especially if they could be kept clean), if it didn't need to use batteries. EDIT:I actually still think we should use advanced "RTGs" of some sort, but they need to be better than they are now, and we need more fuel.
Yes, thought yes.But take a look at thishttp://esamultimedia.esa.int/docs/Aurora/iMARS_Report_July2008.pdfMSR is a science mission. There is NO WAY the scientific community is going to risk their $5-7billion once-in a lifetime mission ( thats the ticket price of the above ) on something as unproven as Martian ISRU propellant.Hence, its not in the concept.EDIT: Its also not in the latest NASA reference MSR design
As discussed elsewhere, proposal to do a ISRU tech demo missions is NOT going to come from science community.You need to find another budget/funding source.Considering Google generously put up $20M for a very basic lunar lander, and its a long shot... i believe martian lander WITH ISRU demo on board is far out of reach for a privately sponsored prize as of now.
More realistic X-Prize goals would be for an Earth-bound Martian ISRU demo tested in conditions that simulate the Martian environment.
Quote from: Robotbeat on 11/01/2010 04:26 pmMore realistic X-Prize goals would be for an Earth-bound Martian ISRU demo tested in conditions that simulate the Martian environment.Like http://moonrox.csewi.org/ ?
You are free to go to http://www.nasa.gov/challenges , find the "Idea submissions" link from the left menu and submit it.As you can see, there are millions of dollars offered for things like autonomous sample return robot right now.