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Europe Heads for the Moon in July
Orlando writes "The BBC are reporting that Arianespace are all set for sending Smart1 to the Moon in July. The mission's primary objectives are testing planetary exploration technologies. This is particularly good news after the recent Arianne rocket explosion." China's also planning a moon mission. The U.S. is planning to sit around and watch.
It's hard to pin the "down on space" tail on Bush. Especially when he's talking about building nuclear powered interplanetary exploration craft that will use ion impulse engines and magnetic shielding for ultra-high energy transfer flights to Mars taking weeks rather than months.
I did some testing, and found that if we are successful in building a ship that can sustain 1 g of acceleration over six days (Prometheus calls for constant thrust to keep astronauts under 1 g of gravity to maintain bone and muscle mass, so it could go a hell of a lot faster), I can send a manned mission to Neptune that will take 40 days to get there. This trip would take 14 years on a Hohmann transfer.
Rough numbers: An ion engine with an exhaust velocity of 30km/sec would have to use up 327g of propellant per second to push a 1000kg vehicle at 1g. At 100% efficiency, this engine would require about 147MW of input power.
To push this vehicle for 1 hour at 1g, it would need an initial propellant load of 2245kg, and an initial power input of 477MW. For 2 hours, it would need 9531kg of propellant and 1.54GW initial input power. The initial propellant load goes up exponentially with the amount of time you want to accelerate at 1g.
Disclaimer: These numbers might be wrong; I'm a bit rusty on my differential equations. And, of course, all these calculations go out the window if someone (other than sci-fi writers) comes up with propellantless propulsion. But I'm not holding my breath for that one.
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But, since the moon is in orbit, thrust is an issue. But the question is, why waste a lot of money getting their fast when you're just sending a robot? It sounds like the ESA is going to get valuable ion engine experience out of this, and at the same time get to the moon cheap. And that's what going to the moon should be; cheap.
If going to the moon isn't cheap, how can we reasonably expect to go to Mars?
Interestingly enough, after the second last ESA launch "problem", the artemis satellite which was on board was brought from low ellipitical orbit to geo-stationary orbit using the only system available, its ion thrusters. Pretty impressive achievement, especially when 20% of the satellites command and control software had to be rewritten to allow the fine control of the engines required.
This is valuable experience for the ESA. They also did some other pretty nifty stuff, like image transfer using an optical link
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To remake the heavy lift Saturn rockets or reconstruct the Apollo heat sheilds, we would have to redo everything from scratch.
that doesnt make any sense. i went to the kennedy space center and they have a saturn V just sitting there.
in fact, who cares? if we were to remake ENIAC right now it'd probably cost millions and require infrastructure to make vacuum tubes that we might not have nowadays, but nobody would say we can't match the feats of ENIAC, or that we're behind where we were in the 40s.
if we really had a reason to go to the moon (and hence a budget to do so), then we'd go. to say otherwise is ridiculous, "Now we don't have a clue as to how to get back." give me a break.