Would going to the Moon delay going to Mars?

[Al_]

Former 'Mars czar' in a Phys.org interview:

There are a lot of questions in the space community about what that means because if you went full-bore on a return to the moon the way it's been suggested in the past – building a base and infrastructure and rockets – that would delay, in my view, humans to Mars by another generation.

Read more at: https://phys.org/news/2018-08-mars-czar-latest-news-red.html#jCp

But would it? Surely the Moon is a perfect launchpad for Mars, a testbed, and a supply base?
Going from Earth direct is a truly huge task. From an established Lunar infrastructure it is much easier surely?

 

[Grinkle]

From an established Lunar infrastructure it is much easier surely?

All of the fuel needed for the trip has to be lifted off the Earth. Parking what's left of it on the moon after reaching the moon and then leaving some later for the rest of the trip doesn't to me seem obviously easier than going in one shot from the Earth.

 

[Ryan_m_b]

The testbed proposal certainly seems viable. Especially if it's a test bed for off-world industry and ecosystem management. Cheaper to ship supplies and safer in terms of bringing people back quickly. Whether or not it delays anything depends, as always, on funding.

 

[Grinkle]

Cheaper to ship supplies

Why would this be? Don't all supplies originate from Earth?

 

[Ryan_m_b]

Why would this be? Don't all supplies originate from Earth?

I meant it is cheaper to ship supplies from the Earth to the Moon than from the Earth to Mars. This is in the context of developing a Moonbase as a testbed for research into off-world industry, long term ecosystem management etc.

 

[Al_]

All of the fuel needed for the trip has to be lifted off the Earth.

But does it? Recently they found evidence of water ice on the Moon. That could be made into fuel.

 

[Grinkle]

Recently they found evidence of water ice on the Moon. That could be made into fuel.

Interesting - you prompted me to do some Googling. Assuming we can really find and access significant amounts of ice on the moon, I wonder if the technology to turn it to fuel can be scaled up enough to make such a project feasible. Certainly there is solar energy on the moon to provide electricity.

 

[russ_watters]

But would it? Surely the Moon is a perfect launchpad for Mars, a testbed, and a supply base?
Going from Earth direct is a truly huge task. From an established Lunar infrastructure it is much easier surely?

Haven't we had this discussion before? No, if you are driving from Philly to LA it does not save you time to stop in Chicago for a year to build a house.

All of the people and resources are on Earth. No matter the route, the starting point is Earth. Adding the largest infrastructure task ever accomplished to the largest exploration task ever accomplished makes the trip longer (and more expensive), not shorter.

 

[russ_watters]

But does it? Recently they found evidence of water ice on the Moon. That could be made into fuel.

There is not, however, an industrial scale mining and manufacturing facility on the moon.

...assuming the lunar water could actually be used, which has not been determined.

 

[Ryan_m_b]

Haven't we had this discussion before? No, if you are driving from Philly to LA it does not save you time to stop in Chicago for a year to build a house.

All of the people and resources are on Earth. No matter the route, the starting point is Earth. Adding the largest infrastructure task ever accomplished to the largest exploration task ever accomplished makes the trip longer (and more expensive), not shorter.

It depends on the context which hasn’t really been clarified. If the objective is to visit Mars and return then a moon base prioritised over that won’t help. If the objective is to develop long term human presence in space then test beds on the moon are wiser than mars.

It’s an annoying topic because of how much Mars scientific exploration has been conflated with Mars colonisation by the media and other outlets.

 

[russ_watters]

It depends on the context which hasn’t really been clarified. If the objective is to visit Mars and return then a moon base prioritised over that won’t help. If the objective is to develop long term human presence in space then test beds on the moon are wiser than mars.

Given that we already have "a long term human presence in space" in a permanently manned space station, and indeed the moon is also in space, it doesn't appear to me that this comment has anything to do with this thread. This thread is about the fastest/cheapest way to get to Mars in terms of timeline and total project budget for the initial trip.

It’s an annoying topic because of how much Mars scientific exploration has been conflated with Mars colonization by the media and other outlets.

And opening posters of threads on the subject.

...or, at least, colonizing the Moon in order to make a trip to Mars.

I'll be completely forthright here on my perception: This OP has created or posted in several threads - probably at least a dozen - with comments indicating he's fantasizing about the subject, not thinking about it. So for this thread: what's cooler than a trip to Mars? A trip to Mars and a colony on the Moon. That's all I see here. Though framed as a question about viability, there is no logic I can see that actually describes a real issue of viability.

 

[mfb]

What do you learn from the Moon for Mars that you can't learn in Earth orbit?

• Long-term effects of low gravity? Surface gravity on the Moon is much lower than on Mars. A centrifuge in orbit would be more realistic.
• How to survive for a long time without resupply missions? You can do that in orbit.
• Long-term effects of higher radiation doses? Earth orbit.
• In-situ resource utilization (ISRU)? The surface chemistry of Moon and Mars is quite different, and the Moon doesn't have CO2 and nitrogen in the atmosphere.
• Produce fuel to go to Mars? Going from Earth to the surface of Moon needs about the same delta_v as going from Earth to Mars. If you have a rocket that can go to the Moon and can go to Mars later you can also directly send it to Mars.
• Make a strong case to go to Mars? I doubt it. People will look at expanding the Moon base.

There is one big advantage of a Moon station: You now have a Moon station.

 

[FactChecker]

For a delta-v discussion, this looks well organized, although there seems to be some debate about some numbers. https://en.wikipedia.org/wiki/Delta-v_budget#Delta-vs_between_Earth,_Moon_and_Mars

 

[Vanadium 50]

This OP has created or posted in several threads - probably at least a dozen - with comments indicating he's fantasizing about the subject, not thinking about it.

Fair enough, but it's also the case that the staff has let this go on. So you can't really blame him.

And before someone inevitably mentions Helium-3, this involves an in situ extraction process that doesn't exist on large deposits of He-3 which are not known to exist to power fusion reactors that don't exist.

 

[Al_]

I see where I'm going wrong here - I meant a minimal infrastructure, just enough to provide fuel, or maybe some other mass-heavy components?

For example, a car-sized ice mining robot and a distillation machine, and solar panels, and some small maintenance and operation robots controlled from Earth. This could provide H2 and O2. We would also need a shuttle rocket to lift it to low Lunar orbit.

I did not intend to imply a full blown Lunar base with human presence etc.

Hard science can consider some alternative ideas sometimes can't it?

 

[russ_watters]

Hard science can consider some alternative ideas sometimes can't it?

How hard is it to build an office skyscraper? It's just a bunch of little 100 square foot offices stuck together, right?

This isn't hard science, it is engineering. But the amount of effort you are putting into the question is just so vanishingly small that I'm going to need to lock the thread (and future ones you create along these lines) if you don't start putting more effort into them. For example:

I see where I'm going wrong here - I meant a minimal infrastructure, just enough to provide fuel, or maybe some other mass-heavy components?

For example, a car-sized ice mining robot and a distillation machine, and solar panels...

Whoa. How much hydrogen do you need? How big is a "distillation machine" and how much power (how many solar panels) will it require? How many and how big are the storage containers for it (answer in number of train tanker cars)?

You're handwaving what in reality is a major mining operation and industrial gas manufacturing facility. Please spend 10 minutes googling, another 10 minutes doing back of the envelope calculations and answer these questions.

...some small maintenance and operation robots controlled from Earth.

You are aware that no such thing exists, right? You can't just handwave away a major technological breakthrough as if it were easy.

I did not intend to imply a full blown Lunar base with human presence etc.

That's only because you didn't put enough thought into it. You are treating this issue not much more seriously than guys who point to Star Trek and say "why don't we just do that?" (we get people occasionally who ask exactly that). You need to start doing better or we won't allow these threads to continue.

...and this is all assuming a refueling station on the Moon would actually be of help, which is apparently questionable itself.

 

[Daniel Sellers]

Haven't we had this discussion before? No, if you are driving from Philly to LA it does not save you time to stop in Chicago for a year to build a house.

All of the people and resources are on Earth. No matter the route, the starting point is Earth. Adding the largest infrastructure task ever accomplished to the largest exploration task ever accomplished makes the trip longer (and more expensive), not shorter.

You have to consider a manned voyage to Mars to be a huge infrastructure task as well. So testing and developing part of that infrastructure on the moon is a valid idea I think.

Stopping in Chicago to build a house might not help you get to LA faster, but you might be able to help the next guy get there faster (because Chicago has less gravity then Philly... ok this metaphor is breaking down). Point is, humanity doesn't all have to travel in the same car.

 

[russ_watters]

You have to consider a manned voyage to Mars to be a huge infrastructure task as well. So testing and developing part of that infrastructure on the moon is a valid idea I think.

If there are things about being on the moon that are helpful, that is true. The question is whether testing that infrastructure/equipment/techniques on the moon would be necessary/more useful or more cost effective than testing it on Earth or in orbit. Per @mfb's list of points, I don't think it would be.

 

[FactChecker]

You have to consider a manned voyage to Mars to be a huge infrastructure task as well. So testing and developing part of that infrastructure on the moon is a valid idea I think.

Stopping in Chicago to build a house might not help you get to LA faster, but you might be able to help the next guy get there faster (because Chicago has less gravity then Philly... ok this metaphor is breaking down). Point is, humanity doesn't all have to travel in the same car.

I don't see the advantage of being on the lunar surface. In orbit, you can build anything, in any direction, without worying about gravity of any kind. Massive structures can be held together in any configuration using minimal-strength components. Why would you want anything else?

Clearly, using the Geostationary Transfer Orbit (GTO) is the most energy efficient way to get material to Mars. Taking a side-trip to the moon is going far out of the way.

 

[russ_watters]

• Produce fuel to go to Mars? Going from Earth to the surface of Moon needs about the same delta_v as going from Earth to Mars. If you have a rocket that can go to the Moon and can go to Mars later you can also directly send it to Mars.

Can we try to clarify this one a bit please. The previously linked wiki article contains the following graphic:

According to that, from Earth to Mars orbit is 14.6 km/s whereas from the Moon to Mars orbit is 4.2 km/sec. Big savings. But to take off from the moon you need to get essentially the entire second and upper stages of a Saturn V to the lunar surface, plus your mining and fuel manufacturing plants, at a cost of 15.2 km/s. So it seems to me like you'd need the total mass taking off from the Moon to be at least 30% larger than what you landed on the Moon to break even. Sound right?

 

[Daniel Sellers]

I don't see the advantage of being on the lunar surface. In orbit, you can build anything, in any direction, without worying about gravity of any kind. Massive structures can be held together in any configuration using minimal-strength components. Why would you want anything else?

Clearly, using the Geostationary Transfer Orbit (GTO) is the most energy efficient way to get material to Mars. Taking a side-trip to the moon is going far out of the way.

The only advantage would be to test and refine a living structure on the lunar surface before taking one to Mars. Admittedly, we can test such a structure on Earth so I concede, there's little to know benefit as far as a Mars mission is concerned.

The two aren't mutually exclusive though. Any mission to space is bound to yield discovery which could be useful later. Per OP, I don't see how a lunar base mission interferes with the goal of Mars except to tie up (as of yet nonexistent) funding

 

[FactChecker]

Considering the I think that the advantage of going to the Moon completely depends on the ability to manufacture fuel on the Moon

The only advantage would be to test and refine a living structure on the lunar surface before taking one to Mars. Admittedly, we can test such a structure on Earth so I concede, there's little to know benefit as far as a Mars mission is concerned.

The possibility of producing fuel on the Moon was mentioned in the OP. If that is practical, it could make trips to Mars much easier. Otherwise, I don't think that being on the Moon gives much of an advantage, and shipping fuel to the Moon for use in flights to Mars would be much more difficult than a direct trip from Earth to Mars.

 

[Grinkle]

The possibility of producing fuel on the Moon was mentioned in the OP.

I didn't find any earth-bound rocket fuel production that is solar panels separating water into hydrogen and oxygen. Does anyone have a reference to such a project?

Certainly its a proven concept and I take for granted many prototype setups exist, I am wondering how large a facility has been constructed to date, and what the challenges are in its operation. Doing some reading about the storage and handling of liquid fuel in general has me thinking that a facility with enough capacity to produce fuel for trips to Mars would be something similar in size and complexity to an oil refinery, but that's only my gut reaction.

 

[mfb]

@Russ watters: I said Earth->Moon and Earth->Mars are similar. Not Moon->Mars. The latter is easier, but unless you start building rockets on the Moon (and that is completely out of range for now), the rockets have to come from Earth.

LEO -> Mars capture is given as 4.3 km/s in your graph, from there on you can do aerobraking and landing on Mars with a few hundred m/s additional fuel (assuming propulsive landing)
LEO -> Moon surface is 5.9 km/s. That is more than the delta_v to go to Mars.

The possibility of producing fuel on the Moon was mentioned in the OP. If that is practical, it could make trips to Mars much easier.

See above: It doesn't - unless you make a complex refueling infrastructure in an eccentric Earth orbit or something like that. But even then the savings are small for a lot of added complexity.

 

[Ratman]

With the plan formulated as "let's go to Mars", direct approach is the best and probably the one that will be implemented, regardless of activities concerning the Moon. But it is not wise. Expect 50+ years between first trip(s) to Mars and permanent exploration base needed to do really good science. Because taxpayers will say "we've already been there". To me it sounds like "I once had a transfer in Frankfurt, what more can I learn about Europe", but it is a real argument you hear when talking about the Moon. The Moon is seriously underexplored, we don't really know what can be mined from it, and we're not using it in any way we could – for example as a testbed for planetary exploration (you can't do geology in LEO, can you).

 

[mfb]

With the plan formulated as "let's go to Mars", direct approach is the best and probably the one that will be implemented, regardless of activities concerning the Moon. But it is not wise. Expect 50+ years between first trip(s) to Mars and permanent exploration base needed to do really good science.

Do you expect an extended Mars base sooner if we first build up a Moon base? Governments will fund extending that before going to Mars at all.
"Fix problems on Moon first!"

 

[Ratman]

At least we would know how to do it. Machines and people work differently in weightlessness on LEO and low gravity. On the Moon you can check if everything works fine in rocky environment where dust sticks to everything, without protective magnetosphere of Earth (another key difference from LEO). You can prepare the procedures needed on Mars. If something goes wrong, you can resupply astronauts and (theoretically) even evacuate them (you can't do it on Mars, sorry Mark Watney). NASA is very protective of its astronauts and I think such arguments are important to mission planners.

 

[mfb]

You can make a rocky environment with "Moon dust" on Earth for a tiny fraction of the cost building anything on the Moon. Even better: You can make "Mars dust" to simulate Mars dust. You can also irradiate it but that wouldn't change the machines. The machines on Earth need more power than necessary for Moon or Mars but that is not a big issue. Testing on the Moon you run into the risk that the machines could be too weak for Mars.

 

[rootone]

Former 'Mars czar' in a Phys.org interview:

Read more at: https://phys.org/news/2018-08-mars-czar-latest-news-red.html#jCp

But would it? Surely the Moon is a perfect launchpad for Mars, a testbed, and a supply base?
Going from Earth direct is a truly huge task. From an established Lunar infrastructure it is much easier surely?

Building an infrastructure on the Moon is not a trivial idea, but it it has to be done if exploring the solar system is a serious project.