Brings back memories of a certain Queller Drive.
"This is the voice of voyager 1, our ship is unmanned and unarmed, we come on a mission of peace and goodwill"
Plans to test a super-efficient plasma space drive aboard the International Space Station (ISS) have been confirmed. The Ad Astra Rocket Company, which is developing the Variable Specific Impulse Magnetoplasma Rocket (VASIMR), has announced the signing of an agreement for the tests with NASA. The view from the ISS The ISS - …
I know we've been here before, but I love the name of this thing, and what it will no doubt be contracted to eventually: Impulse engines. Who cares if it works, just as long as it has a cool name straight out of Sci-Fi!
And it can only be a matter of time before Warp drive comes along. Although, for simplicity, maybe we should just call that FTL drive.
200KW of hot plasma into someone face... Hmm...
As rightfully pointed by Peter F. Hamilton a plasma drive makes a truly devastating weapon at close range. So I would not be so sure if NASA is really putting an engine on it or some defensive armament.
Probably time to rename it Mir 2.
"So I would not be so sure if NASA is really putting an engine on it or some defensive armament."
This is probably a joke but no joke is so crazy that someone won't take it seriously, so I'd like to write about this for a sec.
A VASIMR puts out a minute amount of power. The gas is very hot, and may in fact burn your face if unshielded, but it will do absolutely nothing to another machine, especially not a spaceship. Not one of our spaceships, not an alien spaceship, nothing.
A bog standard 12mm turret gun like from a helicopter would do a lot more and could probably depressurize a Soyuz or Space Shuttle, or ruin a space shuttle's ability to land.
It would work in space, it would not deliver enough kinetic energy to alter the station's orbit and the station's attitude control system could easily deal with the torque from firing a few bullets.
Modern bullets also carry their own oxidizer. Everything they need to go bang is right there in the shell and will work happily in a vacuum.
So physics are perfectly happy with guns in space, and they'll pack far more punch than the 200 kilowatt VASMIR.
All that said, you wouldn't bother putting a gun OR a VASIMR on the station as a weapon anyway.
The only enemy the station could possibly have is China; the station will be deorbited before Iran's space program is far enough along to perform space combat.
And the way China (and the States) smack sats is with surface launched space torpedos.
They come in so bloody fast, with mindblowing closing speed of several kilometers per second, that no gun or plasma engine could ever hope to deflect them.
"The Mars-in-39-days quote sounds amazing - let's just hope that's a realistic estimate and not just overly optimistic."
It's realistic in theory.
It assumes a lot of development on VASIMR has been done, though, and the power processing abilities are in the megawatt range.
It also assumes we have space-rated nuclear reactors, really powerful ones.
Both are plausible. But it's not just around the corner.
If Obama doesn't kill the Moon base, they'll have a ton of work to do short term to push their development.
A reusable VASIMR based solar-electric tug could replace massive upper stages for perform the "translunar injection burn".
This could far more than double the amount of mass any given rocket could ship to the Moon, even the epic monster rocket Ares V.
You could refuel the thing with fuel pods launched dirt ship widow maker rockets.
So this is very exciting to see it's going to be flown and tested on the ISS.
Is the 39 days to reach Mars an estimate based on traveling the distance and going splat into the side of the planet, like recent probes, or is it taking into account the tedious deceleration required to approach at non-suicidal speeds? I'm sure the Martians are getting a bit cheesed off at the amount of crap we keep littering their planet with.
The article seems to imply that this is a new technology. While the specific engine in question is new, the ion drive technology was in operation 10 years ago aboard Deep Space 1. The old engine was referred to as NSTAR and was reportedly developed at a NASA research facility. Perhaps Ad Astra and the VASIMR engine are descendants or spinoffs of that project?
Do they use 200kW to produce just 4N of thrust? I get that the idea is to save fuel here, and energy efficiency isn't the important bit, but I still find it to be very very low. I find myself puzzled though by calculating how much energy they would end up with. Anybody care to enlighten me?
You don't have "plasma drives" in your bathroom unless you have some REALLY unusual candles. Combustion flame != plasma as plasma requires that at least some of the electrons of the plasma constituents have been stripped away, this kind of ionization tends imply really high energy, the kind you just don't get by burning something. VASIMR uses RF to provide that energy and magnetic fields to contain the plasma, something that no physical material is up to doing.
An advantage of doing this is that you can get very high exhaust velocities. The delta V for a rocket, which is essentially a measure of how fast you can get the rocket moving before it runs out of fuel, scales linearly with exhaust velocity and with the log of the amount fuel compared to everything else on the rocket (which explains why exhaust velocity is so important, it is *much* easier to get speed from more exhaust velocity than by increasing the amount of fuel). This is why Dr. Chang Diaz can talk about 39 day trip times: with loads of delta V: you are not restricted to the easier to do, but much slower (closer to 9 months than a little over one month) Hohman transfer orbit. An additional advantage of having delta V to burn (so to speak) is that you don't have to launch during a specific, relatively narrow, window of time or wait two years for the window to recur as dictated by the math of Hohman transfer. You can tailor your trajectory according to when you want to leave instead of tailoring your launch dates to your trajectory.
An additional nice thing about VASIMR, compared to other high exhaust velocity engines (e.g. ion engines) is that you can "gear" the engine, trading some exhaust velocity for more thrust or thrust for exhaust velocity to help optimize performance for a desired mission. As you may be able to tell, I am rooting for Dr Chang Diaz to succeed, I think VASIMR is a very handy type of engine to have space qualified.
Non-space boffins will want a shorter, more descriptive name for what to call the new space engines when they're used in more probes and such. As D. M and AC #1 mentioned, we'll probably end up with either ion or impulse engines... finally settling the Star Wars/Trek debate.
Regarding Greg Trocchia's comment: If it isn't obvious, adding more fuel also adds more mass to your rocket/spaceship/whatever, but doesn't increase thrust. The engine burns longer, but produces less acceleration, limiting the improvement in delta V. This is why Isaac Asimov was pessimistic about interstellar travel being anything other than a very slow, one-way endeavor. The amount of conventional fuel required to get up to a significant fraction of the speed of light (0.1c would take 'only' ~40 years to reach Alpha Centauri), and then slow down at your destination, is simply infeasible. With plasma drives powered by nuclear reactors, we might actually be able to reach the stars.
Of course, even better would be a space drive that doesn't need reaction mass at all. Maybe there's some way to mess around with dark energy...
I think that we should launch Mr. Chang-Diaz along with his trusty drive, so that he'll have his 8th flight into space. Right now, he'd tied for the top spot in flights into space, and I hope that he'll get to break that tie, right quick. Maybe he can later tie a VASIMR onto a Bigelow hotel / module, and boost that stack into lunar orbit. I doubt if he wants to wait in the maid's quarters for the first guests to arrive afterward.
Biting the hand that feeds IT © 1998–2019