Would this engine work..
In the Earth's atmosphere?
(Flying car alert) !
In non-Mars-lander NASA news, it has been reported that the space agency will soon set out concrete plans to test a revolutionary new drive system aboard the International Space Station. The propulsion tech in question is a plasma engine known as Variable Specific Impulse Magnetoplasma Rocket (VASIMR). According to Flight …
39 days??!?! That is blindingly fast! I've heard estimates (for chemical rockets) ranging from several months right up to several years! 5+ weeks is a significant improvement.
Anybody know if this drive is a new design, or just a bigger, more powerful version of the ones NASA have already been using on small probes?
The nuclear reactors on the Soviet RORSATs *WERE* a legitimate cause for concern because a number of them failed to eject their cores into storage orbits at the end of their lives. Which meant that large chunks of intensely radioactive material re-entered the Earth's atmosphere, and on one occasion hit Canada.
They also infuriated astronomers since they were unshielded (to save weight) and their emissions regularly interfered with observations.
RTGs on the other hand are almost entirely safe and the people who protest about those are the usual 'Back to the Dark Ages envirohippies'.
That's really quite impressive! I mean it's routine for a saturation diver to spend almost that length of time in a tin-can (depressurising safely) so it's not like people can't stand being cooped up like that- and in a decent sized vessel you could make it really quite comfortable.
It used to take them longer to sail from one side of the Atlantic to the other, so it's pretty amazing the distances we can now cover in such a short time.
So with this new engine, Interplanetary travel will finally become practical- I may actually get to see my dream of watching a sunrise/earthrise/phobos/diemos-rise from the top of the Olympus Mons. Lets hope this doesn't get bogged down in fear over "OMFG NUKES IN UR SKIEZ 'RADIATIN UR KIDDEHZ!"
It's the blue Oceaneering one with the helmet one small step for a man away.
About 2 weeks. It took Columbus a little over 2 months.
I trust you're aware of "The Mars Ocean Odyssey" (http://1000days.net/home/) where some nut job is sailing non stop for a 100days to make a point about people being able to travel for years on end without it being that big an issue.
There was a time when almost suicidal voyages were commonplace.
Just a little pedantic point. The material ejected out of such a system is not "fuel" by any definition I can find (which generally all refer to the use of a substance to produce heat or power). The "fuel" is in the nuclear reactor which is used to generate the electricity to run this thing.
What is ejected out of the vehicle is the "reaction mass"; that's something ejected at high speed which, by good old conservation of memomentum, results in the vehicle being accelerated in the opposite direction. Of course the fuel and the reaction mass in a chemical rocket are one and the same thing. That is not the case here (or in ion motors).
Just to be clear, the term "reaction mass" as used here has nothing to do with nuclear reactions. Some numpty will no doubt think it is.
So there is more propulsion from a given amount of fuel, but that's basically because if it swapping chemical fuel for nuclear and using a method of ejecting the reaction mass at a much higher velocity that can be done with chemical power (ion motors, which have already been used in space, can do that but the thrust is much less).
Still not as high performing as an orion drive and in space (NOT in our atmosphere) the radiation is not so different from solar winds at a reasonable distance. If you're going to be having nuclear reactions in space this converting-to-electricity plasma drive isn't that efficient.
(Icon is imaginary propulsion drive)
I'm sure we all know that it is physically impossible for a nuclear reactor to explode like a nuclear bomb.
But I will grant you that you can get a (very much smaller) steam-explosion, like at Chernobyl, or what almost happened at Three Mile Island.
But in a Mars-ship, the reactor would be built and run by people with a clue, as opposed to sleep-deprived Soviet "engineers".
If it does still explode, remember that it will be much, much smaller than a commercial power-station, more-than-half of its nuclear fuel would shoot off into space (if it exploded in orbit), and the rest would disperse over such a wide area that it would be practically harmless.
The biggest risk would be on take-off. Rockets do still explode on launch. But that's why the area down-range of the launch site is carefully chosen to be empty of people. And you could always launch it from the middle of the ocean.
Or, you could launch the reactor in stages: More launches does mean more chance of a failure, but it also means that a single failure contains less radioactive material.
The point is, engineers can and will find ways to mitigate the risks. That's what they've been doing since the discovery of fire! Fire, steam and electricity are all potentially dangerous, yet humanity has found ways to minimise that risk while maximising the gains to society.
not alot really without earths atmosphere we'd be dead back ground radiation in space is actually quite high and is one of the limiting reasons of people spending time in space so another nukes worth won't do much what i wanna know is where they store the "reaction mass" are there planning to pick it up as they go along or store for the whole journey from the begining
"Would this engine work.. In the Earth's atmosphere?"
Yes! We need nuclear-powered aircraft.
But whatever the power source, it's actually in some respects easier in air than space because you don't need to carry any gas to throw out the back. The problem is that you have to deal with air resistance, whereas in space you can rely on a long slow acceleration without any resistance to slow you down. See Wikipedia.
I imagine most of the Work watts would be put into the thruster assembly, transferring the energy into the "reaction mass" as a newtonian force and "pushing" it out, providing a resultant desired reaction of forward acceleration.
IOW, those watts wouldn't become heat but rather kinetic energy.
'Anybody know if this drive is a new design, or just a bigger, more powerful version of the ones NASA have already been using on small probes?'
It's never been flown, but has been tested on the ground. It's related to the ion engines that have been used on some space probes, but is capable of producing much higher thrusts.
There's quite a nice article on it at:
'How do you get rid of 12 Megawatts of heat, given that you are in a vacuum?'
There are some really early concept drawings for 2001 which shows the Discovery we're familiar with, but sporting enormous radiators all along its length. They'd got some engineers to design radiators big enough to cool the reactor Arthur C Clarke needed to get his ship to Saturn (yes it was originally Saturn, but they couldn't do the rings). Kubrick decided to dump them as they made the ship much less elegant and he wanted something that looked almost skeletal.
Based on the above comments, only space-hippies would settle for solar powered plasma. Real men drive nukular reacters.
A reactor can be put into orbit in bits and assembled there. Fuel rods are not dangerously radioactive when first manufactured. Besides, a 12MW reactor WILL require shielding after it once goes critical, and shielding is heavy.
How long to Proxima Centauri with this rig?
Really only need shielding between the reactor and the crew. And you need shielding for the crew anyway. One design is to store the reaction mass around the crew area to act as shielding. Water in polyethylene is good for that.
Oh, and you might need some shielding on the pods in case they need to replace the AE35 unit.
Is it just me that thinks its funny that within days of "hydrocarbons" being sighted in the outer solar system, a drive turns up that could get there and back within a year?
All we need now is to find WMDs at wolf 359 and wormhole/M-theory/etc research will be exceptionally well funded.
Mines the coat which is impervious to concentrated molecular acid;-)
OK, here's a back-of-the-envelope calculation. Assuming the trip to Mars (let's be generous and say this is 0.38 AU) is achieved in 39 days using constant acceleration for the first half of the journey and the same constant deceleration for the second half, the acceleration achieved would need to be 0.01 m/s². Assuming the same acceleration could be sustained, to reach Proxima Centauri 4.22 light years away in the same manner would take 90 years...
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Well, if they do the slow spiral orbit with the ISS, they can finally move it to a safe location like the L1 Lagrange point. Then it's at a handy location for the trip to the moon. Else, they can put it at L4 or L5, and use it to stage the fuel depots, hotels, and telescope and research facilities.
We still need to figure out the Red Thunder launcher, to get the cheap ships into space (see John Varley's variation of the standard Heinlein story of the plucky kids who launch a set of railroad tanker cars into space, to tootle around the solar system. They just weight too damned much to get off the ground, where VASIMR will take over.
I hope that Franklin gets to add to his trip total soon with either the Alt Space bunch he's with now, or else a human VASIMR test to a handy asteroid.
Geek with glasses because by now FC-D must need them.