# The Moon or Mars:

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, May 20, 2015.

1. ### billvonValued Senior Member

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Yes, they could. However we have centuries of experience with cables, so that would be the lowest risk item in the entire vehicle.
Yes, in zero-G. Fortunately we will not be using a solar sail on this.
Of course; there will undoubtedly be a test to make sure the engineering is solid.

But as I mentioned, that will be a test of the engineering of the system, not the development of any new technology. I was replying to your statement "At great cost this technology could indeed be developed." The technology does not need to be developed and it will not come at great cost.

3. ### orcotValued Senior Member

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cost can be does not has to be financial the moment you have a large weight swinning you for example lose the ability to use a Ion drive correct?

5. ### orcotValued Senior Member

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nautilus x on the other hand would cost 3.7 billion (well worth the investment I think). Afther the teleoperated robonaut, Vasimr and the low structure solar panels it should be the next big thing on the ISS I hope.

7. ### billvonValued Senior Member

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Last I heard the VASIMR program for the ISS was cancelled.

8. ### billvonValued Senior Member

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Why would you lose such an ability? The engine can be mounted at the midpoint of the cable, or can be pulsed to operate only during prograde orientation.

9. ### orcotValued Senior Member

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heh you where right the VF-200 was scrapped in march 2015 But the unit is still test driving on earth it might still launch in 2018 altough it would be noticebly different the unit would only recuire 80KW (in stead of 200) and it's efficiency would inproof from 40 to 75% resulting in less heat

This is a interesting 5 min YouTube video abouth current progress (you might skip the first 1:50 minutes if you known what a VASIMR is)
In short it's a shame it doesn't get launched but research is still underway and the spike in effeciency is a good thing and it might still be launched in 2018 even if it get's cancelled again the unit is improving.

It also shows that money isn't avaible for everything. I wished the ESA would do more. Sure NASA's on top but both the russians and britain (if skylon works) are outperforming us with less resources.

keeping the engine in the middle prevents you from shielding yourself behing the fuel tank you also need 3 unit's now the rocket, the hab and the ballast. Like a proppeler gun?
It's interior is quit hot I imagen it would degrade the engine and lower it's effeciency if at all possible, it's simply not build for it

10. ### billvonValued Senior Member

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Not sure what a propeller gun is. One advantage of ion drives is their incredibly high exhaust velocity. Combine that with their enormous power requirements and it means that very little fuel needs to be carried. It would be likely that the consumable water to be carried would exceed the mass of the propellant - and water is much better than (say) hydrogen as a shield.

11. ### orcotValued Senior Member

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a propellergun is a (machine)gun that's mounted behind a aircrafts propeller It's firing period is synched with the propller so it can only shoot in between the blades. It would be difficult and include a lot of xtra hardware to keep your engine behind the center of mass of the craft if you can't do that you will need to work in pulses. The exhaust is a plasma and therefore very hot it would not be a good idea to keep that inside.

A vasimr engine could reduce the % of proppelent from low orbit to the moon to roughly 10% in stead of +50% currently the problem is that a 500 watt VASIMR would roughly need a 110 days to place 4 tons in lunar orbit.

On solution would be to do the reverse what's usually proposed in stead of generating power in space and beaming it to earth you could build your power installation on earth and beam it to the craft. (again something that's possible in earth orbit and the lunar surface but not for Mars).

12. ### orcotValued Senior Member

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What would be the point of these missions for the next 50 Years?

If it's Idustrial development
Focused on Earth and therefore the solar system. You would choose the moon, inudstry and infrastructure on Mars would only serve mars intrest.

If it's to support life on earth.
If it is for a power source the moons helium3 might be a obvious candidate but the lunar soil has all the ingredients to make solar panels and beam that power to earth (space station). The lunar surface is also capable to monitor roughly half the surface of the earth ideal for certain types of surface studies. The relative strong gravity also means it's capable to catch very small asteroids that are determined to have valuables for mining this might be a safer option then having them in earths orbit where they are vulnerable to cause a lot of damage.
Whilst mars on the other hand might become a second home people would eventually consider terraforming and splitting the land up between nations this means the norther regions that eventually wil become a ocean will be relativly cheap and have large amounds of water (ice) and more dirtier (cheaper) methods of mining would be allowed because it will end up under severel km's of water anyway, ergo most people will wan't to settle in this region and will activly try to postpone terraforming until they have mined all their riches and afther that it's yust their home. (near my home theirs a region where housing is especially cheap because of a nearby airport because of the noise so they start to live their then they constantly act surprised and try to sue the airport into closer... Never underestimate human stupidity I gues)

If it's scientific discoveries, yeah mars is probably the better candidate, the potential to discover life and how earth and mars developed sepperatly will probably be more interesting then what the moon has to offer. Also the atmosphere of mars is at the triple point of water this is a curious amount of pressure and probably not a coincidence meaning the martian atmosphere might be a textbook atmosphere for alien worlds.
However if the scientific discoveries are of the nature like the ISS then... it's roughly the same for mars and the moon the delta V's are roughly the same and you could only make the argument that the power supply on the moon is cheaper (more sun) and because the travel time for mars is that much longer you probably couldn't do so much experiments with animals (it's hard to keep animals alive for 6 months and they need life support).
Some of the moons more poiseness advantages would be teleoperations that means more qualified personal from the surface of earth could perform the experiments but somehow controlling a robot from a safe room on earth wouldn't push for that much innovation and simply testing. The fact that you can send up replacements much faster and return much faster is more safe but avoids people of fucking with their hardware in a way that could be beneficial afther the first couple of fires and vacuum burns.

And that's why I would choose the moon

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NASA Could Return Humans to the Moon by 2021by Staff WritersWashington DC (Sputnik) Jul 24, 2015

Humans could return to the Moon in the next decade, and for "approximately 90% less than the previously estimated $100 billion," according to a new study by NextGen Space. NASA can cut the cost of establishing a human presence on the Moon by utilizing existing partnerships with commercial service providers like SpaceX and Boeing, said Charles Miller, NexGen president and the study's lead author. By tapping those partnerships, NASA could put humans on the Moon in five to seven years and even build a permanent base 10 to 12 years after that - all without exceeding its current$4 billion budget for human spaceflight, the study said.