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Wow!
I mean, seriously! WOW!! I'd known of the concept of ion drives before. And I was prepared for some "oh we've been doing research on this and we're very close, but..." kinda story. But this is REAL, right NOW. It actually works! True, they haven't done space trials yet, but the engine WORKS.
And the round trip numbers. VERY important. This very much helps with two major problems in a Mars trip (or even extended manned operations in the Earth-Lunar system):
Micro-gravity and Radiation.
One of the BIG stumbling blocks to manned spaceflight has been exposure to radiation in the form of cosmic rays or solar wind. IIRC, If there had been a major solar flare during any of the Apollo Missions while the spacecraft were outside the Van Allen radiation belts, it would've been all over for the astronauts. I believe that's one reason why manned orbital operations stick to low earth orbit so much. We could boost the IST up to a higher, more stable orbit, but that would expose the crew to more long term radiation. They're already getting far more than they should. Heck, airline pilots have cited as one of their reasons for not wanting to submit to a full body scan every time they board one of their own planes is the amount of increased solar radiation they are exposed to at higher altitudes over time. Any Mars mission would need to get there as quickly as possible, or have some form of radiation shelter within the ship (a "storm shelter") in case of solar flares/storms. But such things are heavier than other spaceship components due to the necessary mass. And Mars has no shielding radiation belt in any case. In the case of both potential Lunar and Mars outposts/colonies, the first thing you have to do is DIG to get down to a point where you are shielded from solar radiation.
Micro Gravity is a more subtle problem. It's not immediately life-threatening, but over time, the body loses bone and muscle strength/mass. Ever read The Moon is a Harsh Mistress? While the book is becoming rather dated in certain respects, Heinlein treats the issue of acclimatization to different gravity environments (particularly becoming used to heavier Earth Gravity) in a way that is still relevant today. Astronauts/Cosmonauts only have a limited amount of time in space before changes in the body become almost irreversible. That can be measured in months or maybe even a couple of years with a heavy exercise regiment. But it will happen. Any mission to Mars has to factor in the need to get the crew back in time before they become unable to function in Earth gravity any more.
But what about spin habitats? Well that'd be a way to slow that process down. But there's a problem. The diameter of a spin habitat that would be able to give the equivalent of 1G would be... well it's pretty damn big. There's a practical limitation on how fast you can spin the wheel before Coriolis effects start to produce nausea and other problems. So the habitat has to be larger in diameter to compensate. (There were two major problems in concept with the spin habitat on the Discovery in 2001 A Space Odyssey. It was WAY too small, and there would need to be TWO of them. With one spinning the opposite direction to counter the spin of the first one.)
A compromise is to design the spin habitat for simulation of lower G values. It still limits the mission time. But it does extend it versus having nothing at all.
In any case, this new drive system makes solving the above issues MUCH easier. With constant low-powered thrust, you can still move lots of mass to good Delta-V. Put a low-g spin habitat on the spacecraft and a good radiation shelter and a drive capable of getting them there and back in under 6 months and you've GOT your Mars missions!
With this drive added to the IST, no more need for the space shuttle or a Salyut to boost it to maintain orbit. Just leave the drive on as long as you need to maintain station-keeping.
Heck, with this kind of drive, you could afford to have something massive enough in Near Earth Orbit that building those classic wheeled spinning stations might not be infeasible now! The constant low-level boost would keep nearly anything from plummeting out of orbit.
I still don't expect much from NASA or the government in general on this (or ANY government). No nation these days has the political will for major manned space exploration anymore (with the possible exception of China).
But in the private sector? WIth Burt Rutan and Virgin Galactic and Space X and now this? Suddenly the PRIVATE exploration of space looks a lot more feasible now.
Now if we could just have Robert Heinlein back to be "The Man Who Sold the Moon" again. *sigh*
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On the topic of a radiation shelter in long term space craft:
This is neatly taken care of by two things you need to deal with already. Food and waste. Both are full of complex organic molecules that do a grate job of absorbing the high energy radiation that can cause real problems.
So depending on how much food you have to bring, you design a section of the ship that can be lined with the needed thinkness. And everyone runs there when the solar radiation gets heavy. They have even designed an (and this is the term the scientist used) "easy bake oven" that can produce nice stackable bricks of waste. I think they designed the oven as a way to reclaim water originally.
-Terry
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"so listen up boy, or pornography starring your mother will be the second worst thing to happen to you today"
TF2: Spy
