How much money have we got for this?If we go lunar too early, we might be stuck there.Too expensive, and then: done that, didn't work.A small station, MCT sorties, why not.
Powered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.
As much as I would like to go to Mars. I would rather be stuck on the Moon, than in LEO...https://www.nasa.gov/pdf/55583main_vision_space_exploration2.pdf
Antarctica and Northern Canada would be much less expensive (and safer) places to test a lot of this stuff, except hab reliability in very low pressure. Everything else that is specific to Mars (ISRU chemistry) either can't be done on the Moon either, or can be simulated on Earth (such as living with 40 minute communication delays). Indeed, some people have already been doing this.Powered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.
{snip}What certainly can not be tested on moon: Greenhouses. 14 days daylight, puts some plants under severe stress. 14 days night, and quite a lot of plants just die.{snip}
In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?What things could be tested on the Moon before trying them out on Mars?
What kind of projects might be beneficial for lunar science even while supporting greater goals for Mars?
Yeah I think the important thing is that you are stuck somewhere that forces a moderate fraction of your budget to go to LS, self sufficiency and ISRU. In this case being stuck may actually be a good thing. It would trap some budget into actually being applied to space settlement despite politicians actively fighting money escaping to any useful technology development.
Arctic plants may be able to take the midnight sun.Curtains and lighting can be used to simulate the 24 hour day. Particularly if we move the plant house underground to protect against radiation.
Quote from: A_M_Swallow on 01/23/2016 11:02 pmArctic plants may be able to take the midnight sun.Curtains and lighting can be used to simulate the 24 hour day. Particularly if we move the plant house underground to protect against radiation.And the relevance to Mars?
However, if you are "stuck" on the moon, it would mean that the program specifically didn't deliver those things.Just as Constellation, as VSE, was originally meant to develop ISRU fuel technology, but instead quickly devolved into an equatorial base. Then devolved further to a handful of flags'n'footprints Apollo-on-steroids landings before being cancelled entirely.A non-cancelled Constellation, stripped of everything useful while still somehow consuming all available funding. That's what "being stuck" means.
How similar are the regolith fines in the two environments? Both are near vacuum, but Mars perhaps has enough atmosphere that the particles will be more rounded than the Moon's notoriously sharp, interlocking granules.Nevertheless, I think a lot of work could be done in learning how to manage dust in a nearly-Mars-like environment, with normal cyclng of seals and mechanical joints. You might counter-argue that it could be done with regolith simulant in vacuum chambers on Earth.Paul451: why would suits be significantly different? Heat-load is the only major difference I can think of.(Edit: lunar suit would need micro-meteoroid protection. Optional extra layer?)
Quote from: ThereIWas3 on 01/23/2016 09:46 pmPowered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.Mars landing is radically different to a Moon landing, though some technologies are common - but not enough to justify test missions to the Moon on the way to Mars. The Moon remains, however, a worthwhile near-term goal - and probably a more politically acceptable one for state space agencies.
The Moon and Mars are sufficiently different that I don't think it would be efficient to reuse much technology between the two missions. So I agree that the argument of reuse of technology is not a good one. However, what I do see as useful is the experience gained in performing complex Lunar missions. That experience is what I believe will lead to a successful Mars mission.
About the only commonality would be equipment within the pressurized habitat. Virtually everything else will have to be different. ISRU methods will be different. Thermal control (for both surface habitats and spacesuits) will be different. Power production and storage will be different. Lander design will be different. Moon: Day / Night cycle of 28 days (~200 C temperature swings from day to night), no atmosphere (thermal control must be done by radiating away the heat), much less water (excepting polar locations with permanently shadowed craters), 0.16 g gravity. ~3-4 days transit time from Earth, very frequent launch windows. <1 second radio delay for communications with Earth. Mars: Day / Night cycle of 24 1/2 hours, less temperature extremes (~90 C from day to night), very thin atmosphere (but sufficient for some radiation protection and allows for thermal regulation by convection), much more water available in the top soil, 0.376 g gravity. ~6 months transit time from Earth with launch windows every 18 months or so. 15-40 minutes delay in radio communications with Earth. Things like rovers and spacesuits that are designed to work on the surface of the Moon will not work on Mars, and vice versa. If your end goal is to go to Mars, then yes, going to the Moon first is nothing but a very expensive diversion from your goal. If you want to go to Mars, then go to Mars. If you want to go to the Moon, then go to the Moon. Both are very worthy destinations for science, exploration, and future economic exploitation, but going to one does not really help you in going to the other.
Having the human environment systems debugged on the Moon will save the Mars team a fortune.
{snip}Focus on Mars, and some of the hardware might be able to be modified for a lunar infrastructure. Focus on the moon, and very little will be useful for Mars.[I don't mean solely MCT either. If you had a DRA 5.0 Mars system with an LEO-LMO transfer ship with separate lander(s), those landers and the engine and power module for the LEO/LMO ship would be useful for lunar missions. You just wouldn't need the long duration habitat and life-support for the Earth/Mars trip.]
A LEO-LLO transfer ship may not need a long duration habitat and life-support but a Moon base does.
Quote from: A_M_Swallow on 05/10/2016 04:35 amA LEO-LLO transfer ship may not need a long duration habitat and life-support but a Moon base does.A surface life-support is likely to be significantly different from a micro-g ECLSS. One intended for either polar or equatorial lunar day/night cycles is going to have radically different requirements to one intended for LEO, BEO-space or Mars surface.
In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?What things could be tested on the Moon before trying them out on Mars?What are the differences between the 2 environments that would have to be accounted for?What kind of projects might be beneficial for lunar science even while supporting greater goals for Mars?
Quote from: sanman on 01/23/2016 05:34 amIn what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?What things could be tested on the Moon before trying them out on Mars?What are the differences between the 2 environments that would have to be accounted for?What kind of projects might be beneficial for lunar science even while supporting greater goals for Mars?The moon can be used to test the business case for a Mars colony. Most of the GDP of a colony will be the generation of intellectual property. Much like Antarctica, the vast majority of people there will be researchers who's institutions or governments are paying for their time there. Residents will be a fraction of the total population. A moon outpost let's you try out all your support functions for that economic activity, but without the time, expenses, and danger of a two year trip.
US and China collaboration.
Quote from: turbopumpfeedback2 on 05/12/2016 02:08 pmUS and China collaboration....is prohibited by law.
Quote from: sghill on 05/12/2016 04:49 pmQuote from: turbopumpfeedback2 on 05/12/2016 02:08 pmUS and China collaboration....is prohibited by law.Laws can be changed.
Quote from: A_M_Swallow on 05/12/2016 05:18 pmQuote from: sghill on 05/12/2016 04:49 pmQuote from: turbopumpfeedback2 on 05/12/2016 02:08 pmUS and China collaboration....is prohibited by law.Laws can be changed.Yes, but not this one as long as the Republicans control Congress.
In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?
More that a stepping stone to Mars, Moon is it own destination.Very insteresting in long term, because is a very good place for robotic telepresence.
But the biggest reason to go back to the Moon in my opinion is that it can act as a testing ground for TTP (tactics, techniques, and procedures) in a harsh environment with a moderate safety risk.
Quote from: sanman on 01/23/2016 05:34 amIn what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?As many have said before me:The environmental differences between the moon and mars are big enough that you'd have to have specialized solutions for each environment (abrasive lunar dust is a big one).But the biggest reason to go back to the Moon in my opinion is that it can act as a testing ground for TTP (tactics, techniques, and procedures) in a harsh environment with a moderate safety risk.While it takes pretty much the same delta V to go to the moon as Mars...the big advantage is travel time.You can launch to/from the moon pretty commonly and travel times are pretty short:Going to/from the moon (liftoff [earth or lunar] and landing [earth or lunar]) takes 4~ days as opposed to 150 to 300 days for Mars.This short cycle enables you to do a lot of realistic training far away from earth, but not so far away that if something happens, you're pretty much dead.Plus, the short cycle enables a lot of iterativeness, making it possible that in the near-future (25-35 years from now), the career progression for an astronaut/cosmonaut/taikonaut would be:Stage 1: Low Earth Orbit / Space Stations = A few hours away from help if something goes wrong.Stage 2: Lunar Orbit / Lunar Surface = A few days away from help if something goes wrong.Stage 3: Mars = Months away from help if something goes wrong.Allowing the candidate to progress in their training to higher and higher levels.Plus, it provides off-roads for the training system; because even if the person may not be cut out for Mars missions, they're still good for LEO/Lunar missions -- important if we're to move towards a space program with large masses of people living or working off-earth, instead of only a few highly trained and handpicked specialists working off-earth at any one time.
Quote from: RyanC on 05/21/2016 02:07 pmBut the biggest reason to go back to the Moon in my opinion is that it can act as a testing ground for TTP (tactics, techniques, and procedures) in a harsh environment with a moderate safety risk.What advantage does operating a pretend Mars base on the moon have over operating a pretend Mars base in a remote area of Earth?The disadvantage being the extra tens of billions of dollars necessary for NASA to operate a moon base.I mean, if little of the hardware can be common, what benefit is there that is worth the enormous cost?
building up a cislunar infrastructure in no way requires or needs us to take jaunts from there on down the lunar surface. Any surface exploration out of a cislunar station is a separate thing from the development of habs and transit modules for Mars, and can't really help us prepare for Mars. It can only take away funding from a Mars goal.
Quote from: the_other_Doug on 05/21/2016 05:51 pmbuilding up a cislunar infrastructure in no way requires or needs us to take jaunts from there on down the lunar surface. Any surface exploration out of a cislunar station is a separate thing from the development of habs and transit modules for Mars, and can't really help us prepare for Mars. It can only take away funding from a Mars goal. That's not necessarily true. Beefed-up versions of the Moon landers that ULA proposed based on their ACES platform could land on Mars; albeit you'd have to do it mostly fully propulsively. This was discussed here years ago. Basically you'd be trading the cost of propellant for the cost of developing a brand new Mars lander that would require a fancy EDL system where you'd use aerobraking to shed the vast majority of Mars orbit delta v. Also, it's hard to imagine what a single stage, reusable Mars lander would be like based on the latter design because the TPS is going to weigh a lot, and the delta v for taking off is going to be basically the same as that required for a fully propulsive descent. Maybe you could have a SpaceX-style returnable 1st stage, so the actual capsule would be able to land on its own, but then it could be mated to the reusable first stage for relaunch. Sounds good, but when contemplating such monsters, the concern for lunar missions sucking away Mars funds then becomes real.This points out two very different mind-sets when it comes to Mars exploration. There are those who prefer the Apollo-on-steroids, flags 'n' footprints, mass-starved architecture, and there are those that prefer a sustainable, long-term presence that will make evolutionary use of existing architectures, as well as space resources to ensure that something as simple as rocket propellant will always be available in an abundant supply.As for habs, if one would suffice for the surface of the Moon, I don't see how it would not also work on Mars. If anything, it'd be a bit overengineered. But so what. The idea that brand new architectures have to be designed for Mars missions is a guarantee of massive cost overruns. According to Doug's logic, a 3rd-stage designed to boost communications satellites to GEO has no business being included in the design for a manned lunar lander. After all, satellites don't require pressurized chambers and life support systems, and the Moon's surface is a very different environment compared to LEO or GEO. In reality, a Mars architecture based on a lunar architecture based on ULA's ACES combined with Bigelow-style habs would work admirably IMHO.YMMV
And in its entire existence ESA hasn't even done a lunar orbiter.
That ease of teleoperation of robotic rovers demonstrates the lack of scientific interest in the moon by major agencies.In 40 years, NASA hasn't put a single lander or rover on the moon. They've flown a small number of low-funded orbiters, but not followed up on the interesting findings of those orbiters. Even during Constellation, which Bush justified as lowering the cost to Mars, there was no serious proposal for a lunar lander or rover, not even to do a ground assay of the supposed polar ice deposits.
Supposedly, SpaceX is proposing non-mass-starved architecture. If true, and if achievable, then a lot of what we're talking about here really stops being applicable...
Quote from: the_other_Doug on 05/21/2016 08:54 pmSupposedly, SpaceX is proposing non-mass-starved architecture. If true, and if achievable, then a lot of what we're talking about here really stops being applicable...If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.
Quote from: Warren Platts on 05/24/2016 02:32 pmQuote from: the_other_Doug on 05/21/2016 08:54 pmSupposedly, SpaceX is proposing non-mass-starved architecture. If true, and if achievable, then a lot of what we're talking about here really stops being applicable...If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.Mars.
Propellantless launch isn't necessary if you have lots of reaction mass available. On Earth and Mars, that's not really a problem. This thread's author seems to claim it's not a problem on the Moon, either (though I'm skeptical).
If NASA wants to go to Mars, it'd be a huge waste for NASA to go to the Moon just for propellant. I guarantee FAR more money will be spent by stopping off at the Moon first.
Now if private companies think they can deliver lunar water or propellant to orbit for cheaper than you can get from Earth, then they should offer it to NASA for a fixed price. NASA ought to have mechanisms in place to allow that. Same for alt-launch from Earth or atmospheric scooping or asteroid resources, etc. But I guarantee NASA will explode the costs and there's simply no way it'd be cheaper for NASA to go to the Moon first.
Quote from: Robotbeat on 05/24/2016 05:15 pmPropellantless launch isn't necessary if you have lots of reaction mass available. On Earth and Mars, that's not really a problem. This thread's author seems to claim it's not a problem on the Moon, either (though I'm skeptical).Propellantless launch, when practical (it's tons more practical on the moon than either Mars or Earth) dramatically cuts down on the amount of mining and infrastructure you need in order to support a given rate of propellant export. ...
I'd say propellantless launch options are usually more infrastructure-intensive than reusable chemical launch. Again, if reaction mass is easily available, you don't need or even necessarily want propellantless launch (though useful for assists, maybe).
CO/O2
Quote from: Robotbeat on 05/24/2016 05:57 pmCO/O2 What about for the MTV voyage home?
My point was about propellantless launch of ISRU propellant from the Moon, where a) propellantless launch is *much* easier than for Earth or Mars due to the much lower orbital velocity and the lack of atmosphere you have to deal with, b) can be less infrastructure intensive than even setting up the ISRU system to feed it payloads, and c) makes a big economic difference to the cost of propellant from the lunar surface.
Propellantless launch, when practical (it's tons more practical on the moon than either Mars or Earth) dramatically cuts down on the amount of mining and infrastructure you need in order to support a given rate of propellant export. For the Moon, there are options for propellantless launch that could be landed in a single ACES/Xeus landing that could cut the amount of prop you'd need to produce on the moon by nearly half. Half the required infrastructure, half the required landings.
Quote from: jongoff on 05/24/2016 06:12 pmMy point was about propellantless launch of ISRU propellant from the Moon, where a) propellantless launch is *much* easier than for Earth or Mars due to the much lower orbital velocity and the lack of atmosphere you have to deal with, b) can be less infrastructure intensive than even setting up the ISRU system to feed it payloads, and c) makes a big economic difference to the cost of propellant from the lunar surface. OTOH, if you have enough activity in cis-lunar space to justify the construction of any form of propellantless launch from the lunar surface, it implies you've already solved whatever problem you are trying to solve with propellantless launch.
I want to follow up on this... is there a paper somewhere I should go read? To me propellantless means magnetic catapult. Even at reeealllllly high acceleration I'd assumed you need quite a lot of mass in a launcher. When you say "could be landed" what do you mean? As a kit that someone has to put together? With some ISRU components? Or self contained? Or do you mean something that unrolls/unfurls self deploys? Does the kit include the solar cells or NTU to power it and the batteries or is that assuming an existing ISRU plant that powers this for a bit?
Nothing is free, things have varying levels of difficulty to obtain so whether it's worth it to use one thing or another depends on the situation.
This technology is essentially a land based train that takes excess electrical energy and stores it through potential energy gained in large train masses. In rudimentary terms, it’s the equivalent of pushing a large rock up a hill when you have the energy so you can push it down later when you need more energy.
Bumphttp://interestingengineering.com/concrete-gravity-trains-may-solve-energy-storage-problem/QuoteThis technology is essentially a land based train that takes excess electrical energy and stores it through potential energy gained in large train masses. In rudimentary terms, it’s the equivalent of pushing a large rock up a hill when you have the energy so you can push it down later when you need more energy.
Quote from: Lar on 05/24/2016 10:02 pmI want to follow up on this... is there a paper somewhere I should go read? To me propellantless means magnetic catapult. Even at reeealllllly high acceleration I'd assumed you need quite a lot of mass in a launcher. When you say "could be landed" what do you mean? As a kit that someone has to put together? With some ISRU components? Or self contained? Or do you mean something that unrolls/unfurls self deploys? Does the kit include the solar cells or NTU to power it and the batteries or is that assuming an existing ISRU plant that powers this for a bit?I've been meaning to do a blog post on this, but it's been a previous topic on this forum (hint, hint). But yeah, I think a single ACES/Xeus lander could land the main system and the rest of the "kit" to setup a specific type of propellantless launch system that could put 1mT payloads into lunar orbit on a regular basis.~Jon
Yeahhhhh... wildly inefficient from a volume: power perspective and on the Moon, six times less efficient than *that.*
Quote from: Lampyridae on 08/16/2017 11:16 amYeahhhhh... wildly inefficient from a volume: power perspective and on the Moon, six times less efficient than *that.*Unless .. you are using local materials.
this would be to prove that the notion of glass domes would or would not have been a viable on the moon.
Energy storage tends to be heavy any way you slice it. Using local materials would obviously be beneficial, question is at what stage do you try to do that, and how high tech can you get.
Minor aside:Quote from: NIVbV-O77OdV-VSVN-Op-SLE7 on 08/16/2017 06:13 amthis would be to prove that the notion of glass domes would or would not have been a viable on the moon.Domes are compression structures, they are rarely viable when containing a higher pressure (such as air, in a vacuum.) If you are containing pressure, it is, by definition, a pressure vessel and hence should be shaped like a pressure vessel.(Even if you pile mass on top of the dome to artificially outweigh the force from the contained gas, that gas is still trying to blow out the sides, particularly where the floor joins the side (and that's assuming a gas-tight floor.) Hence the optimal shape would still be a classic pressure-vessel, but "squashed" by the top mass. A low, oblate spheroid, or elongated, ellipsoidal equivalent.)[Nothing to do with energy storage, just one of those SF tropes that annoys me.]
When comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.
Quote from: TrevorMonty on 08/16/2017 05:13 pmWhen comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.2a) Earth based power beamed to the surface (if you are on the lunar nearside and have multiple earth beaming stations)
Quote from: TrevorMonty on 08/16/2017 05:13 pmWhen comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.4) Normal solar. Site the base at one of the poles, near a peak of (nearly) eternal light. That limits your dark time to a few days, depending on how high you can mount the panels.
Laser transmission is not very efficient compared to microwave but surface receiving equipment for laser is solar panel compared to complex rectenna and power conversion equipment.
The peaks of "eternal light" are nice but limit the base locations severely.
...A space elevator is allowed too.
Kitchen equipment for the galleys. If we cannot design machines for both which work in a shirt sleeves environment we are not trying. Kettles, food mixers, fridges, microwave ovens, blenders and conversional ovens are likely to be needed. With reduced gravity motorised equipment may need fastening to the work surface. Water handling equipment on Earth, including sinks, assumes 1g to provide pressure.
First space elevator should be built on the Moon.
Quote from: A_M_Swallow on 09/15/2017 11:30 amKitchen equipment for the galleys. If we cannot design machines for both which work in a shirt sleeves environment we are not trying. Kettles, food mixers, fridges, microwave ovens, blenders and conversional ovens are likely to be needed. With reduced gravity motorised equipment may need fastening to the work surface. Water handling equipment on Earth, including sinks, assumes 1g to provide pressure.You're assuming that 0.165g is a suitable test for 0.38g.{snip}
Quote from: Paul451 on 09/15/2017 08:53 pmYou're assuming that 0.165g is a suitable test for 0.38g.I am assuming that if it works at 1g and 0.165g then the device is highly likely to work at a middle value like 0.38g.
You're assuming that 0.165g is a suitable test for 0.38g.
Quote from: A_M_Swallow on 09/16/2017 09:51 amQuote from: Paul451 on 09/15/2017 08:53 pmYou're assuming that 0.165g is a suitable test for 0.38g.I am assuming that if it works at 1g and 0.165g then the device is highly likely to work at a middle value like 0.38g.If you're just checking whether a relatively off-the-shelf Earth system still works at reduced gravity -- eg, whether water still flows through a tank/pipe/tap/drain/pump/recyc -- you don't need a lunar base, it's a relatively simple yes/no question. A small unmanned elongated satellite in LEO, spun for low gravity, would give you that information for a tiny, tiny, tiny, tiny fraction of the cost of building and maintaining a manned lunar base.Surely the point of the question is whether things designed for the unique conditions of the Mars (things not suitable for testing on Earth) can be tested on the moon, or things built especially for the moon can be generalised for Mars. And, implied, whether that's enough justification for using the moon as a stepping stone to Mars. Does it make things easier/cheaper?[It'd be different if a lunar base cost about the same to run as, say, a remote research station on Earth. But you still wouldn't be justifying a lunar base as a Mars experiment, it'd simply be a lunar base for its own sake. You'd send stuff to be tested simply because it's there. Just as you would use an existing spin-station in LEO for testing rather than build a bespoke test satellite (or the moon), simply because it's already there and paid for.]
You are assuming that the only reason for a Moon base is as a test facility for Mars.
Quote from: A_M_Swallow on 09/17/2017 08:18 amYou are assuming that the only reason for a Moon base is as a test facility for Mars.No, I'm assuming that was the premise for the thread. Given that it spun off from the moon-first-then-Mars vs Mars-only argument.
Quote from: Paul451 on 09/17/2017 10:37 amQuote from: A_M_Swallow on 09/17/2017 08:18 amYou are assuming that the only reason for a Moon base is as a test facility for Mars.No, I'm assuming that was the premise for the thread. Given that it spun off from the moon-first-then-Mars vs Mars-only argument.Do not forget the third option Moon only.