Return to the moon

[Simpo Two]

JuniorD said:

There's a lot of talk about using the moon as a stop off point on the way to Mars. Now the moon is very inhospitable, and the most mankind has managed to do up there is fart about for a few days and plant a flag and leave some abandoned kit.

The achievement was getting there and getting back. Man's greatest achievement. What did Amundsen, Scott, Hilary etc when they got to their goals? Plant a flag, take a photo and go home. Goal achieved.

The issue with using the Moon as a stopping point to Mars, I believe, is getting in and out of the gravity well, which requires more fuel and more complexity/chances of stuff going wrong.

[annodomini2]

JuniorD said:

There's a lot of talk about using the moon as a stop off point on the way to Mars. Now the moon is very inhospitable, and the most mankind has managed to do up there is fart about for a few days and plant a flag and leave some abandoned kit. It strikes me that building a space port on the moon for a future Mars expedition and all the associated infrastructure and equipment would be a nigh on infeasible, perilous distraction? Surely the handiest way for a mission to Mars is a direct flight?

The Moon is more an experiment to understand and develop the technologies required to operate a base on another world.

With a lower risk than going direct to Mars, the moon is 2 days away, not up to 3yrs with current propulsion tech.

Would they launch rockets to Mars directly from the moon, unlikely. Mostly for the reasons you list.

[Beati Dogu]

NASA is working with DARPA (the Defense Advanced Research Projects Agency) on a nuclear powered rocket engine. These are much more efficient than chemical rockets and don't require an oxidiser as well as the actual fuel (hydrogen). They hope to have a working flight model by 2027. The Demonstration Rocket for Agile Cislunar Operations (DRACO) spacecraft.

Heres NASA administrator Bill Nelson announcing it recently:

https://www.youtube.com/watch?v=-jmS6pDF3Ho

It's not a new idea of course:

https://en.wikipedia.org/wiki/Project_Rover



Not directly related to this, but NASA recently released footage of their first full-scale rotating detonation rocket engine (RDRE). Another technology that promises greater efficiency than conventional designs.

https://www.youtube.com/watch?v=jBWUim-rppQ

Best explained here:

https://www.youtube.com/watch?v=rG_Eh0J_4_s

[Simpo Two]

annodomini2 said:

With a lower risk than going direct to Mars, the moon is 2 days away

A bit more than two, unless rockets are going much faster than Apollo did.

[hidetheelephants]

InitialDave said:

drmotorsport said:

Indeed, maybe we shouldn't have come down from the trees in the first place.

Even the trees were a bad move, no one should ever have left the oceans.

But what about the digital watches!?

[annodomini2]

Simpo Two said:

annodomini2 said:

With a lower risk than going direct to Mars, the moon is 2 days away

A bit more than two, unless rockets are going much faster than Apollo did.

It was an approximation, even though I didn't indicate it as such.

More a representation of the difference in access time for the Moon vs Mars.

[Eric Mc]

Simpo Two said:

annodomini2 said:

With a lower risk than going direct to Mars, the moon is 2 days away

A bit more than two, unless rockets are going much faster than Apollo did.

It's not a question of the capability of rockets. The length of time taken to get to the moon - or any other body in the solar system - is predicated more on the mass of the payload being carried and how you want to make best use of the consumables on board the spacecraft i.e. fuel, life support etc.

The Apollo missions generally too about 3 to 4 days to get to the moon - which was the best option given the nature of the mission. The SMART ion drive probe of about 20 years ago took months to get to the moon. The New Horizons probe to Pluto zipped past the moon's orbit after only a few hours of launch from earth. That was a record at the time (2006) but has since been superseded by the Parker Solar Probe which was launched in 2021. However, note that these two probes were not going to the moon itself so were travelling much faster at the moon's orbital distance than they would need to need if intended for lunar orbit.

[glazbagun]

SBF said:

JuniorD said:

There's a lot of talk about using the moon as a stop off point on the way to Mars. Now the moon is very inhospitable, and the most mankind has managed to do up there is fart about for a few days and plant a flag and leave some abandoned kit. It strikes me that building a space port on the moon for a future Mars expedition and all the associated infrastructure and equipment would be a nigh on infeasible, perilous distraction? Surely the handiest way for a mission to Mars is a direct flight?

If you have the option to leave Earth with a lighter fuel load, stop at the moon for fuel, then liftoff from the Moon (where there is also less gravity to overcome, so weight is less of an issue) it’s something worth exploring.

SpaceX have also suggested the possibility of setting up Tanker versions of the Starship architecture in orbit to allow orbital refuelling of normal Starships (again, liftoff with less fuel weight / higher payload capacity, refuel, then be on your way).


Sure, sounds far fetched and complex, pointless or impossible to some people, but in the last couple of years we’ve had Rockets landing themselves out at sea, rockets landing themselves in pairs side by side on land, and a crew of 4 normal members of the public sent into orbit on a 3 day mission aboard a recycled booster, so I’m going to let them get on with it and enjoy the process and potentially see some amazing things in my lifetime, rather than st on and ridicule the thousands of people working hard day in day out trying to do cool stuff.

NASA has it's Gateway project as part of the Artemis program- a permanent manned lunar space station which sounds just in the sweet spot between ambitious and totally nuts.

https://en.wikipedia.org/wiki/Lunar_Gateway

I guess, like previous space milestones, it will come down to political will. Unlike near earth space I'm not sure there's any commercial value in going to other planets unless someone finds a mountain of pure lithium or some other rare earth metal.

[jingars]

SBF said:

SpaceX have also suggested the possibility of setting up Tanker versions of the Starship architecture in orbit to allow orbital refuelling of normal Starships (again, liftoff with less fuel weight / higher payload capacity, refuel, then be on your way).

The internet has gone rather quiet on this topic of late, but Starship tanker missions are a prerequisite for Artemis III, the first lunar landing mission.
The suggestion is that possibly 12 to 14 Starship tankers will need to be launched to LEO to fully fuel the SpaceX Starship lunar lander prior to it heading to the moon.

[Eric Mc]

The John Hubold solution still seems the most sensible to me.

[jingars]

Axiom Space - 2023


Helios Aerospace - 1995

[Panamax]

Old fashioned rocketry involves hundreds of tons of fuel to get out of earth's gravity with only a small capsule returned at the end.

Elon Musk (Space X) reaches orbit but only his first stage returns for reuse. Space Shuttle had plenty of problems.

The issue is simple: deceleration and heat of re-entry.

The idea that anyone is going to mine tons of lithium in space and return it to earth as a high value resource is complete nonsense. It would arrive as a meteor and burn up in the atmosphere. Similarly any space craft travelling at very high speed (for instance a "fast" trip back from Mars) could never survive re-entry.

[Simpo Two]

Panamax said:

Old fashioned rocketry involves hundreds of tons of fuel to get out of earth's gravity with only a small capsule returned at the end.

Elon Musk (Space X) reaches orbit but only his first stage returns for reuse. Space Shuttle had plenty of problems.

The issue is simple: deceleration and heat of re-entry.

The idea that anyone is going to mine tons of lithium in space and return it to earth as a high value resource is complete nonsense. It would arrive as a meteor and burn up in the atmosphere. Similarly any space craft travelling at very high speed (for instance a "fast" trip back from Mars) could never survive re-entry.

I think the trick is to use gravity deceleration - but either way, the price of whatever it brings back would be impossibly expensive.

You'd be better off making your own lithium from fusion. H - He - Li... make any element you want...!

[glazbagun]

So is there any medium-term economic case for Earth-based humans going beyond the moon? I can't think of one beyond getting really good at jetting around space for it's own sake. The ultimate offshore tax haven?

If there's nothing in the solar system that would be worth the expense of bringing it to earth the only alternative would be to send labour to space which, again, doesn't really benefit those down here unless you're making something which can only be made elsewhere. If there were hydrocarbons on Mars at least you could burn them to your hearts content, but there aren't as far as we know.

[Simpo Two]

glazbagun said:

So is there any medium-term economic case for Earth-based humans going beyond the moon?

It's more about exploration, beating other countries for national pride and technology spin-offs that have a role back on Earth.

[SBF]

glazbagun said:

So is there any medium-term economic case for Earth-based humans going beyond the moon?

<stuff>

If there were hydrocarbons on Mars at least you could burn them to your hearts content, but there aren't as far as we know.

Perhaps we should go and have a look...?

[Beati Dogu]

You’re not going to be burning much of anything on Mars. The atmosphere, such as it is, is about 95% CO2 and only 0.2% oxygen.

You can’t even have a nice cup of tea outside, since the boiling point of water is about zero Celsius. It’s a total nonstarter as a British colony.

[Eric Mc]

Maybe the Martians will becoime big consumers of iced tea. If I was Liptons I'd be making plans.

[nordboy]

Cupramax said:

Am I the only one looking at this and seeing after all this time all they’ve managed is to build a new Saturn V which went to moon originally, meanwhile Musk is landing rockets after use if I was the head of NASA I’d be too embarrassed to even let it take off.

You do actually know that NASA, SpaceX, Boeing etc all work quite closely together, and whilst they're separate entities, and they use different tech etc, there is definitely a plan between them all. They all do things a bit differently to maximise the results.

[Simpo Two]

Cupramax said:

Am I the only one looking at this and seeing after all this time all they’ve managed is to build a new Saturn V which went to moon originally, meanwhile Musk is landing rockets after use if I was the head of NASA I’d be too embarrassed to even let it take off.

If I was the head of NASA I'd point out that my rocket can get men to the moon whilst Musk's is a toy.

Landing a rocket backwards is a clever party trick but is it much use for space exploration?