Author Topic: What Could Be Tried on the Moon Before Going to Mars?  (Read 14375 times)

Offline Asteroza

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #80 on: 08/18/2017 08:59 AM »
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.

2a) Earth based power beamed to the surface (if you are on the lunar nearside and have multiple earth beaming stations)

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.

2a) Earth based power beamed to the surface (if you are on the lunar nearside and have multiple earth beaming stations)

That would be as expensive to develope as the moon colony itself. And highly inefficient as well.

Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #82 on: 08/18/2017 09:49 AM »
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.

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.

Offline Lampyridae

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #83 on: 08/21/2017 02:02 PM »
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.

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.

Regenerative fuel cells seem to be what NASA is leaning towards. The peaks of "eternal light" are nice but limit the base locations severely.

https://www.nasa.gov/content/regenerative-fuel-cells-energy-storage-systems-being-developed-for-space-applications
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Online TrevorMonty

Which ever system you use there is significant extra mass and complex equipment. With SBSP most of mass and complex equipment is in orbit where delivery costs from earth are lot cheaper. Surface assets are fixed solar panels. The other plus is satellite can supply multiple bases as it orbits. If only one satellite is used, base will still need storage for when satellite is over horizon. Add extra satellite and you double power production for multiple locations. 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.

Besides landing costs of lunar power systems there is also the assembly and on going maintenance.
« Last Edit: 08/21/2017 04:11 PM by TrevorMonty »

Offline Steven Pietrobon

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #85 on: 08/22/2017 06:11 AM »
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.

You still need power conversion equipment with solar panels.
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Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #86 on: 08/22/2017 12:31 PM »
The peaks of "eternal light" are nice but limit the base locations severely.

It limits you to the only parts of the moon that justify a manned presence. It prevents you from putting ISRU-fuel in the "too hard" basket and instead adopting what turns out to be a higher-risk, Altair-like strategy; which, due to added size and cost of the lander, and hence size and cost of the launcher, results in more and more of the actual "base" being deferred forever and the goal being reduced to flags'n'footprints redux. It therefore ensures that the only Mars-related thing which can be tested on the moon (ISRU-fuel related activities) is actually tested on the moon.

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #87 on: 09/15/2017 11:30 AM »
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.

Offline savuporo

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #88 on: 09/15/2017 02:23 PM »
...A space elevator is allowed too.

That'd be the one. First space elevator should be built on the Moon.

Also, powersatellites pointing lazorbeams down to the robots in the darkness.
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Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #89 on: 09/15/2017 08:53 PM »
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.

You're assuming that 0.165g is a suitable test for 0.38g.

First space elevator should be built on the Moon.

A space elevator is almost always a poor use of resources. (A 200,000km long cable? Seriously?) There are much better tether systems for the moon.

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #90 on: 09/16/2017 09:51 AM »
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.

You're assuming that 0.165g is a suitable test for 0.38g.

{snip}

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.

Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #91 on: 09/17/2017 02:46 AM »
You'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.]
« Last Edit: 09/17/2017 02:46 AM by Paul451 »

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #92 on: 09/17/2017 08:18 AM »
You'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. There are plenty of other reasons for building a Moon base. A lunar establishment is likely to have its own galley, bathroom, bedrooms, life support, land transport, communications and work areas. Designing a second version of that equipment will increase the cost and time scales of the Mars manned mission.

Offline savuporo

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #93 on: 09/17/2017 08:46 AM »
Here's one: staging mission elements on surface side by side. Not currently possible on Mars.
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Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #94 on: 09/17/2017 10:37 AM »
You 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.
« Last Edit: 09/17/2017 10:38 AM by Paul451 »

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #95 on: 09/17/2017 11:35 AM »
You 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.

I want both. The Moon is nearer and I suspect the Moon base can be operational before we can get a man to Mars.

Offline Paul451

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #96 on: 09/18/2017 01:27 AM »
You 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.

Again, I'm talking about the topic for the thread. Not a general discussion on "What do I think NASA/humanity should do in space next?", but a subset of the discussion, "What is the value of the moon to Mars exploration?" focusing down to testing/trials.

[Don't get me wrong, I'm more than happy to have that broader discussion/debate/argument/angry-rant/insults/Mod-warnings/thread-locked-with-several-users-banned, but this is not that thread.]

Offline A_M_Swallow

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Re: What Could Be Tried on the Moon Before Going to Mars?
« Reply #97 on: 09/18/2017 01:03 PM »
You'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.]

NASA does not have to justify building a lunar base as a Mars experiment but using part of an existing lunar base to test Mars equipment.

Any engineer designing equipment for Mars has to say why for say an additional 20% in cost the equipment cannot be used on both the Moon and Mars. ISRU equipment that processes Mars's atmosphere cannot be used on the Moon because the Moon does not have an atmosphere. Where as knives and forks will work on both planets.

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