So apparently congress has decreed NASA must go back to the moon again before going to Mars:
We know there’s permanent water ice at the poles in shadowed craters. Would it be feasible (using current technology) to make use of this as a fuel source for future missions beyond the moon? If you can set up solar panels in sunlit areas and then have rechargeable roaming robots collecting water ice and returning it for electrolysis (again powered by the solar panels) seems like you’ve got a huge amount of potential usable reaction mass that’s in a much shallower gravity well than the earths.
Liquid oxygen + liquid Hydrogen could then be launched back to earth orbit where it can be used for fueling missions beyond earth orbit. Make sense or does the economics just not work out?
In my state of just knowing enough to be dangerous, the idea of a moon base always had some appeal to me. But I’m pretty certain those truly in the know provided persuasive arguments why that would not be terribly efficient or useful. I believe a moon base would take tremendous resources while providing limited benefit. Whereas those resources could, instead, be directly applied to whatever other mission was our actual goal. And government resources for space exploration aren’t exactly unlimited.
The smart people will be here in about 10,9,8,7,6,5,4,3,2,1…
Of course what the House actually did was defund the existing program and not fund another one to replace it. They simply stated that we should go back to the moon. Good plan. And exactly what we were doing when the columbine report was written. That report noted that at the funding level congress was actually setting, we weren’t going anywhere. NASA came up with a plan that got us somewhere (lunar orbit) with the funding congress was willing to pass. Not that I am a fan of the asteroid redirect mission, but it was what could be done with the funding available.
Pretty soon, like as soon as the advanced heavy lift booster design is finished, NASA will find there is no money to actually use one. But by that time, the design and test engineers at Marshall and in Utah will be done anyway and those jobs will be already gone.
Yes but it may come down to NASA paying SpaceX / Blue Origin / Bigalow / SNC etc to achieve the goals congress sets. That would not be the worst possible outcome. I don’t care if NASA does it direct or if they pay the new space entrepreneurs to do it. Doesn’t change the original question I’m asking on if there’s a feasible way to use the resources already on the moon to assist in getting elsewhere.
The new space entrepreneurs don’t have equipment to send stuff to the moon or the financial incentive to develop it.
NASA can’t pay anyone if they’re not getting more funds.
We don’t have the technology to use the water ice on the moon and doing so would require developing whole new industries, so it entirely depends on what you mean by “feasible”, and how much wild speculation you’ll allow.
Another possibility that NASA was looking into at one point was extracting oxygen and hydrogen directly from the lunar regolith and converting that into rocket fuel and water. I know they have been able to do this in the lab…all it takes is a power source, which presumably the astronauts would need regardless. I don’t think the main issue is getting water in situ on the Moon (or Mars), it’s protecting the astronauts from the high levels of radiation. The Moon would be a good mission for trying out habitats and other technology that NASA would need to do a Moon trip. I kind of hope that this is a real (and funded) program…NASA has been making noises about a Mars mission in the 2030’s, and even working on some of the systems they would need, including a new heavy launch system and command capsule, but it all seems pretty nebulous at this point, since things seem to change with each administration.
As I understand it, the Falcon Heavy has plenty of payload capacity to the moon, but the Dragon isn’t well suited for a moon landing. It doesn’t have anywhere near enough propellant to go from lunar transfer to the surface. It also carries a lot of weight for systems that are useless on an unmanned lunar lander, like the heat shield and the pressure vessel, and relatively high-thrust but inefficient thrusters. Conceivably, SpaceX could design some kind of service module or lander, and modify the Dragon to reduce its weight. But at that point it’d probably be a lot simpler to design a dedicated lunar lander.
In comparison, it’s actually a lot easier to land on Mars than the Moon since the atmosphere will slow down the Dragon enough that it can carry enough fuel for the final landing burn.
A manned lunar lander is another matter entirely, and is far beyond the capabilities of even the Falcon Heavy.
That puts us in the realm of politics: nobody in Congress, NASA, or SpaceX is interested in funding a heavy unmanned lunar lander. Congress is interested in funding a manned lander to justify the [del]Senate[/del] Space Launch System.
Is it feasible to make rocket fuel on the moon? Yes. Does it make sense from an economic standpoint to establish a permanent moon base for the processing of lunar rocket fuel to supply future deep space missions? I would say in the current time frame, no.That’s not to say returning to the moon isn’t a good idea for other reasons. I’ve read that money spend on USA’s original lunar program had something like a 20 dollar return on every dollar spent, back into the economy. In other words the technological leaps made in the effort were enormously beneficial to American companies. However, to bring the cost down, we first need to invest in an alternate way of getting things into space besides rockets. I know that Arthur C. Clarke was a big proponent of the space elevator.
No, we do not have the technology to do this. But that’s the wrong question to ask. We didn’t have the technology to land on the Moon the first time until 1969. The time we spent on the Apollo project (and Gemini, and Mercury) was in developing and building that technology.
So, could we build the technology to do this? Yes, but again that’s the wrong question to ask. The real question is how long would it take us to build the technology, at what cost.
It is impossible to discuss economics because we don’t even currently have the technology do to this (robotic collection plus in situ production of propellants), nor sufficient experience in this regard to make a credible estimate of cost. If, or more optimistically, when we elect to establish an infrastructure for in situ production of propellants extracted from space resources, it will likely make much more sense to focus on Near Earth Asteroids, certain classes of which are closer and easier to reach in terms of energy expenditure than the Moon, notwithstanding the cost and complexity of launching material from the Moon’s gravity well and the significant difficulties of operating on the Lunar surface environment for extended periods (see NASA/TM—2005-213610/REV1 The Effects of Lunar Dust on EVA Systems During the Apollo Missions, James Gaier, April 2007).
As someone who has worked on multiple studies for interplanetary missions for a Mars landing I have to say that seeing this misapprehension repeated again and again is extremely frustrating. Among those hose who have worked on Mars entry, descent, and landing (EDL) systems it is nearly a mantra that Mars is the most difficult solid body in the Solar System to land upon. This is because it has just enough atmosphere to be problematic in terms of aeroheating and aeroloading, erosion, and suspended particulates (dust), but not enough to decelerate and come into a gentle landing at low subsonic speeds for anything with a mass over 1 metric ton. A large craft (large enough to carry a propellant production facility or crewed mission) will require a large deployable deceleration system (like the Low Density Supersonic Decelerator) or a very heavy ablative thermal protection system, or else will have propellant requirements for a purely propulsive landing that will take most of the payload capacity of your landing vehicle. Landing on Mars is a fundamentally difficult problem that remains to be ‘solved’ to any degree of technical maturity before we can contemplate practicable plans about delivering large payloads to Mars.
That is very much true subject to the previously stated issue of charged Lunar dust, and in fact that observation can be made about pretty much all space exploration at the present or projected levels of propulsion and habitation technology for the foreseeable future. Although it seems like people should be able to do much more than robotic probes and rovers given our dexterity, intelligence, et cetera, once you stuff a person in a pressure suit, subject them to extremes of thermal radiation, and cause them to spend so much effort and attention dealing with their life support systems that they can only do a couple hours of productive work over a 10 hour work period, it turns out that purpose-designed robotic probes are nearly as capable at any specific task, and the state of the art in robotics in being capable of adapting to a wide variety of tasks is jumping forward by leaps and bounds, while personal life support technology isn’t much better than it was circa 1970 and human physiology and behavioral modalities hasn’t changed significantly in, oh, about the last fifty thousand years or so. Given a relatively generous extrapolation of costs for crewed LEO missions to even interplanetary missions versus robotic missions, we could litter the entirety of the Solar System with robotic probes for the cost of a single crewed mission to Mars. The reason to put people into space is two-fold; to get better at it until the technology is sufficiently mature to get to Mars or onward without desperate, high risk “flags and footprints” destination-oriented missions; and to put the mission controllers operating the probes and rovers closer so as to perform near-real-time operations rather than with delays measured in hundreds or thousands of seconds.
Fair point, I was being imprecise and thinking only in terms of propulsive delta-V. Obviously landing large spacecraft is a solved problem on the moon but not so much on Mars. My larger point was that the Dragon spacecraft is in no way suitable for a moon landing.
For everyone besides Stranger, who surely knows this already:
I’ve seen estimates that the Dragon 2, unmodified, has somewhere in the 400-500 m/s ballpark. For the Red Dragon mission, there will be additional fuel for entry, descent, and landing. Going from public figures in earlier studies of the Red Dragon mission (6.2 ton spacecraft + payload, 3.2 tons of fuel, 235 s specific impulse) the modified Red Dragon would have ~960 m/s. To land on the Moon, by comparison, would take somewhere around 900 m/s for Lunar orbit insertion, and then another 1700 m/s to land. That’s far beyond what is feasible with the Dragon.
If those are the estimates for landing a 6200 kg (dry mass) spacecraft on Mars using aerodynamic drag of a blunt base capsule and supersonic retropropulsion with 3200 kg of propellant for a total of about 7.4M N･s of total impulse, the claim is farcical on the face. For even the best theoretical chemical propulsion systems at I[SUB]sp[/SUB] ~450 s in a direct entry, high base drag EDL mode, a propellant mass fraction of >0.5 is required. Realistically, landed masses in the multiple ton range will require propellant mass fractions >0.6, and practically speaking the general assumption is that least a single stage inflatable decelerator will be required to achieve both good targeting and high landed mass fraction, which is an important cost driver in minimizing the number of ground-to-orbit launches and on-orbit integration and fueling operations.
In the 'Eighties and early 'Nineties, it was assumed in many studies that a broad base biconic vehicle would be able to fly aerobraking and supersonic aerolift entry trajectories with good precision and a high landed mass, requiring only terminal-phase propulsion to land. However, once we got more data about the atmosphere of Mars the aerothermal analysts started taking a hard look at aeroheating and realized that the thermal protection system requirements would result in either a really heavy ablative heat shield or complex active cooling that would not be capable of being made redundant, and was therefore a critical failure mode with minimal margins. Since that time, Mars mission studies have recognized that base drag aerodynamics can only provide modest deceleration capability and supersonic retropropulsion, while technically possible, required a lot of technical development to sufficient maturity (TRL>7) and had extreme propellant mass fraction requirements. The proposed “Red Dragon” mission is of course a smaller landed mass than anything that would be considered for a crewed mission but the challenges of landing even a multi-single-ton mass are substantial, and I’ll believe Musk’s claims when I see them demonstrated in reality versus PowerPoint.
In fact, you’d probably want to keep your controllers in orbit. For the 300%+ mass penalty to deploy a 40+ ton crewed vehicle to a single location on the surface of Mars (plus prestaging a habitat, supplies, mobile exploration vehicle, and potentially an ascent vehicle), you could deploy dozens of ~1000 kg rovers, probes, and penetrators across the surface of Mars at various latitudes and at any longitude you desire, and the controllers can apply their attention to which ever rovers or probes are doing active tasks while others follow predefined tracks under semi-automated guidance or perform interval sampling. By remaining in orbit they have the most rapid access to rovers (especially with a satellite relay system), and they can easily observe ground conditions, as well as not being subject to the risks of descent and ascent, abrasive dust, and the potential of contaminating samples with terrestrial microbiota. (The potential for biological contamination in the other direction, i.e. Mars to astronaut, is remote but still a potential risk.)
Now, I’m framing this out in terms of getting maximum science value for cost and effort. There are other objectives that may benefit or even require a human presence on the surface, such as planting flags and putting down footprints, testing methods for future human occupation, et cetera. There may be political, social, or educational value in performing these activities, though justifying the extreme cost and significant risk generally requires some kind of national objective of asserting dominance over a competitor (e.g. the Cold War of the 1947-91). But we can do so much more valuable science and exploration with remote exploration for far less cost than a crewed landing mission that it really shouldn’t even be consideration for comparison based upon science value.