Author Topic: What Could Be Tried on the Moon Before Going to Mars?  (Read 17324 times)

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #40 on: 05/12/2016 05:18 PM »
US and China collaboration.

...is prohibited by law.

Laws can be changed.

Online RonM

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #41 on: 05/12/2016 05:54 PM »
US 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?

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.

Also other business activity such as ISRU production of propellent. The equipment won't be the same as used on Mars, but the propellent can be used for flights to Mars. We'll see how the economics work out.

Offline turbopumpfeedback2

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #42 on: 05/12/2016 09:37 PM »
US and China collaboration.

...is prohibited by law.

Laws can be changed.

Yes, but not this one as long as the Republicans control Congress.

The ban is only 5 years old. A lot can change on a timescale of decades.

In the case of optimistic estimate:

1) China lands on the Moon at about 20 years from now
2) Ten years after that US and China  start building lunar base

the ban could very easily be lifted by then.

« Last Edit: 05/12/2016 09:44 PM by turbopumpfeedback2 »

Offline Spaniard

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #43 on: 05/19/2016 08:13 PM »
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. Negible atmosphere allows rail launch into Earth orbit.
A space elevator is allowed too.

Interesting as source of some water, oxygen, titanium, aluminiun, silicon, etc.

In short term, a interesting platform to make our first scientific colony. We could test low gravity, artificial gravity on surface, long term support, some IRSU building and manufacturing, remote telepresence, buildings for robot protection (while moon night), etc. etc.

But the key to be succesful in long term is that we need to add incremental reusable infrastructure, so we could have more and more resources while maintain a plain spending.
This is the reason because I think that the Mars brute force approach I think that it has a lot of probability of a death end. Yes... you can visit Mars some times, but later would be another Apollo v2.

We need a incremental infrastructure. Only one spot, not one different each time. Robots and other machines with standard pieces to replaces ones with anothers. Custom building (3d printing or local manufacturing to make easy replacements).
Ion tugs to move cargo between Earth and Moon. Tethers. Rail launcher and/or space elevator  on Moon. IRSU for oxygen. Perhaps water. Local food production...

Incremental infrastructure and shared approach. A step beyond ISS. Not big rockets, but orbital depots , tethers and similar to make more missions, more shared, opened to competition and cooperation.
And make the colony only get bigger. What reach Moon surface, it would be there "forever". Future recicling.

So, once the main ships (tugs, depots, tether points...) was deployed, we could lower the spending and ensure that the colony never cancels.

Because Mars mission would be bigger and less robotic, it probably be tried on a "one mission/one place" approach, and fail in long term.
We need a big colony with frequent visits, new experiments, robots, IRSU...etc.
Too difficult on Mars when each mission has near two years of duration.

Mars would need a very autonomous colony from start. Like a Moon base but with little mistakes.
So we would need be very confident of our capabilities and resources.
Probably we need to spend some decades on Moon before to try not only technologies, but organization and long term colonization.
ISS approach on Moon surface with as much IRSU and reusability as possible.


Offline RyanC

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #44 on: 05/21/2016 02:07 PM »
In 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.

Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #45 on: 05/21/2016 05:07 PM »
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.

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.

And in its entire existence ESA hasn't even done a lunar orbiter.

It's one of the things I find frustrating about the talk of manned lunar missions. "You won't even fund a fracking remote-controlled rover!"

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.

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?

Offline the_other_Doug

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #46 on: 05/21/2016 05:51 PM »
In 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.

I see your point, Ryan.  I just disagree that the experience gained on lunar missions can easily be translated to missions with much farther destinations.

The best parallel to what you're describing is how NASA always says that they used the Gemini missions to train both ground support staff and flight crews for Apollo.  And it's true, they used Gemini to perform maneuvers and manage missions that, in terms of complexity, did rival what they would be doing later on in Apollo.

And that's where the "preparation" aspect ended.

Apollo engineers and managers for the most part disdained lessons learned from Gemini, saying (with a faint air of superiority, as described by Mike Collins) that "it's simply not done that way in Apollo."  Equipment was different, capabilities were different, operations were different.

What NASA learned from Gemini, to be honest, was the "Mission Control" paradigm for operating large, complex space flights.  Mercury was so limited that the Mission Control paradigm wasn't able to expand to where it needed to be to manage an Apollo lunar expedition.  It was during Gemini that everyone in the MOCR learned how to train, how to tag up with the Flight Director, how to make decisions while thirty voices were mumbling into your ear... and to select those people capable of doing it.

John Aaron didn't amass the knowledge of Apollo systems that made him a "steely-eyed missile man" working Gemini.  The Gemini knowledge he gained was basically useless when he started working on Apollo systems.  Just as the Apollo knowledge a lot of flight controllers had amassed was of little direct use when they started flying the Shuttle.

Now, the question really is, what can we learn that we can't learn via simulations about mounting a manned Mars mission by mounting lunar expeditions?  Not how to operate the lander and surface equipment -- as has been pointed out, those hardware elements have to be a lot different for lunar landers than for Mars landers, due to quite different environmental factors.

And the real-time Mission Control paradigm has already been perfected, over a lot of years with Apollo, Shuttle and ISS.  In reality, the biggest thing that has to be invented and perfected is a new Mission Control paradigm, one that can be effective when your spacecraft are not light-seconds but light-minutes away from the ground controllers.

Hence, your description of ISS = immediate help, Moon = 2-3 days from help and Mars = months from help is flawed in terms of the actual support a manned spacecraft can get from the ground.  It's more like ISS = support within fractions of a second of an issue, Moon = support within three seconds of an issue, Mars = ground can't see an issue until it's likely killed you, so no effective minute-to-minute support.  At all.

So, in that frame of reference, there is almost no difference between LEO and lunar operations.  There is a very significant difference between both LEO and lunar operations and operations light-minutes away.  Thus, you learn nothing from lunar operations in terms of supporting spacecraft that are light-minutes away.  The paradigm is identical to LEO operations.

The only way to develop and perfect a new Mission Control paradigm without actually going light-minutes away from Earth is via simulation.  And if you're going to simulate it, does it make sense to spend tens of billions of dollars to put humans on the lunar surface in order to put simulated 12-minute comm delays (each way) into the stream?  Can't you do that with ground simulations, or even simulations of operations using assets in-place, like the ISS?

And while the development of DSH-type hab modules in cislunar space can be valuable in preparation for Mars missions, 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.

I know that common sense says "just use the same stuff you're going to use going to Mars, just go to the Moon instead and we'll learn how to use it."  Problem is, the environments, both physically and operationally, are so different that I question the value of spending tens and tens of billions of dollars on landing crews on the Moon just for the limited training and development opportunities it might provide for follow-on Mars missions.  It's sort of like saying "Before we use this bathyscaphe to descend to the Challenger Deep, let's test it by descending from the rim to the floor of the Grand Canyon."  Nice idea in theory, but the environmental conditions for each descent are so very different that it won't provide any useful information to apply to the mission for which you're designing the bathyscaphe.

Don't get me wrong, though.  I support and encourage a return to the Moon with humans, I really do.  I just think it ought to be a separate lunar exploration program, not associated with Mars expeditions.  I also think that we can get international involvement in a new lunar exploration program, with ESA and JAXA providing the lunar lander and lunar surface equipment.  Spread out the cost and land international crews on the Moon, using cislunar infrastructure designed to support future Mars missions.

So, if you want to get to both the Moon and Mars in the next few decades, I'd say it's possible.  But it's not going to happen because the Moon is a good place to check out Mars landers and surface equipment -- because it just isn't.
-Doug  (With my shield, not yet upon it)

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #47 on: 05/21/2016 07:58 PM »

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.

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?

It will be a real Moon base. The Mars team just guests.

On Earth with difficulty we can simulate space by put a habitat in a vacuum chamber but we cannot drive a rover very far.

Having a genuine vacuum that undergoes very large temperature change every two weeks will force everything to be space rated and have full life support. Example problem has the MMSEV been equipped with a ECLSS yet?

Offline Warren Platts

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.

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
« Last Edit: 05/21/2016 08:39 PM by Warren Platts »
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Offline the_other_Doug

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #49 on: 05/21/2016 08:54 PM »
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.

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

This is actually where I am on tenterhooks awaiting SpaceX's announcement of its Mars architecture.  Be it flags-and-footprints or permanent base, the NASA DRA is mass-starved.  Everything we're discussing here is mass-starved.

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...
-Doug  (With my shield, not yet upon it)

Offline savuporo

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #50 on: 05/21/2016 08:59 PM »
And in its entire existence ESA hasn't even done a lunar orbiter.

Nitpick : SMART-1
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Offline Spaniard

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #51 on: 05/23/2016 06:52 PM »
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.
It's not about scientific achievements. It's about reducing human intervention on real cases and bring IRSU in a long term way. You can't make massive IRSU with astronauts. You need a lot of "standarized" robots, building a robot ecosystem, reusing as much parts as you could and making "robot shelters" too (not so complex like manned shelters but allowing less thermal stress on nights for example, or less dust for mainteinance).

The problem of previous architectures is that they don't take IRSU very seriously. Only for fuel, and mainly in Mars because Zubrin's Mars Direct proposal.

I say that we should make IRSU the key stone of successful space colonization. Fuel is not enough. Electronics are too complex, but bulky raw materials that surround the fragile components. Others things wouldn't use destination raw material but local production (like local printing/manufacturing) so only raw material package should be need to transport.

This approach would result in incremental results with a plain expending, that it's just what we need.
A sprint Apollo project would bring a lot more results but at a price of "burn" space interest (and later budget) very quickly. We must avoid the mistakes of the past.

A International approach is needed for long term success and a incremental infrastructure too.
Mars is too far, and the result would be huge effort disconnected missions. The same Apollo style of the past.

Moon could have a interconnected and redundant international cooperation and competition. With compatible but independent rockets to LEO, orbital depots or tugs in orbit, Moon landers and different Moon base modules.
The small time windows allow these cooperation without too much precise timing. Only a connection of compatible infrastructure that could work for years between multiple missions.

Offline Warren Platts

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...

If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline Robotbeat

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #53 on: 05/24/2016 03:35 PM »
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...

If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.
Mars.
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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #54 on: 05/24/2016 04:18 PM »
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...

If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.
Mars.

For a Mars mission, getting resources at the Mars end is a no-brainer. Of course not lugging all of your landing, ascent, and return fuel from Earth makes sense. That said, if lunar propellants can be competitive with Earth-launched prop in either LEO or some near-lunar departure point (EM-L1, L2, or lunar NRO), then it can also play a major role. And I think with propellantless launch and eventually landing infrastructure, that the Moon can beat even RLV launch prices for propellant in LEO. And while that's controversial, I think it's less controversial to say that lunar sources can beat out earth-launched sources for propellant at the high-port at EM-L1/L2, or lunar NRO.

Now, how we get there is a different problem, but I think that if done wisely, lunar propellant could be an enabler for Mars missions. Not that you couldn't theoretically do Mars missions without lunar propellant, but that the cost equation isn't likely to come close to closing without every bit of help Mars can get (lunar ISRU, depots, martian ISRU, aerocapture, etc).

~Jon

Offline Robotbeat

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #55 on: 05/24/2016 05:15 PM »
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.
« Last Edit: 05/24/2016 05:21 PM by Robotbeat »
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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #56 on: 05/24/2016 05:41 PM »
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).

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. Could you do with out it? Sure, but you'd be stupid to.

Quote
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.

That's why I added the "if done wisely" caveat. NASA isn't going to go anywhere wisely. Congress wouldn't allow it. Which is why while I think "going to the Moon first" could be a good idea, I don't want NASA focused on doing lunar missions itself. I'd much rather them keep their sights on Mars, with the Moon being something that they support by public/private partnership. :-)

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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.

Yeah, I definitely was not advocating for a return of a NASA-centric return to the Moon. I'd much rather see NASA keep wasting its big money on Mars, while participating in ESA's lunar village concept, as a contributing member, via public/private partnerships. Ie think of how ESA and JAXA support ISS today by contributing to cargo launch in exchange for a crew member, but in NASA's case, they save money by having private companies provide the cargo services, in exchange for NASA being able to send an astronaut... But keep their main focus on Mars. I don't care about Mars as much, so am less worried about NASA screwing that up. :-)

~Jon

Offline Robotbeat

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #57 on: 05/24/2016 05:57 PM »
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).

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.
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Not true. For Earth (water) and Mars (CO2), no mining required. An optimal Mars-to-orbit vehicle would run on CO/O2 because you don't need to do any mining. Then it's just electrolysis, which is a very small amount of infrastructure, and energy to run the propellant production. That energy is not significantly different than the energy needed to run a propellantless launch platform, and in fact, a propellantless launch platform requires a huge burst of energy which is itself a large infrastructure requirement, plus energy wasted in the launch cart (might be recovered a bit, but not at perfect efficiency and would require even more infrastructure).

...and for Earth, you don't even need electrolysis, you can use natural gas as the fuel (the cheapest, in dollar-price, form of energy available right now) and oxygen from the air.

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).
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online jongoff

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #58 on: 05/24/2016 06:12 PM »
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).

I wasn't talking about propellantless launch from Mars or the Earth. You're the one who keeps bringing that strawman up.

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.

~Jon

Offline Warren Platts

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