Of course, for interplanetary stuff, a solar sail is even better.
A radical electrically-powered space rocket which has the potential to cut months or years off travel times to other planets has achieved a further successful test today. The new milestone for the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) was achieved with the aid of a crucial new component - a superconducting …
It's all very well accelerating at ridiculous speeds to get to Mars in just over one month instead of a year. But I hope the brakes are good because you might want to stop when you get there!!
One of the biggest problems for getting to Mars and back safely isn't necessarily the food situation, or oxygen, or even landing a spaceship. It's cosmic radiation, which can do seriously nasty things to your body with long-term exposure. On Earth we're protected from this by the Earth's magnetosphere, and it extends far enough out that the ISS is within it too. The only human exploits beyond the magnetosphere have been the Moon missions, and those only lasted a few days so no big deal. On a multi-month mission though, this is a deal- (and astronaut-)killer.
With this in mind, a spacecraft design which uses a sodding great electromagnet would seem to be a bit of a result - not only can you get there faster, but your drive system will inherently protect you from radiation nasties during the trip. It may need a bit of rethinking to make it happen, but it seems like you can kill two birds with one stone. Or more accurately, stop any birds (and blokes) being killed.
so no pointy eared visitors dropped by yet? guess will have to keep inventing *sigh*
Oh, I think it'll stop when it gets there...
dont worry about stopping you just insert directly into a faster orbit then if required you can slow your speed and move to a slower orbit...
Anyway most to mars calcs are based on getting half way and timesing by two, as accelerating = deccelerating.
Wouldn't "one of the largest and most challenging cryogen-free superconducting magnets ever built" cause significant difficulties when in close proximity to large metal objects of the kind magnets stick to? Such as presumably the ISS?
Might not be a good idea to turn it on until you're out of orbit, all that junk flying around, OTOH you could use a giant magnet to clear up a lot of it, provided it can withstand the impacts.
(Yes I know a magnet probably wouldn't deflect an object much unless it was either moving slowly or very close, neither of which should apply to orbital debris, it was just a funny thought, and presumably it could be turned off for docking).
"It's all very well accelerating at ridiculous speeds to get to Mars in just over one month instead of a year. But I hope the brakes are good because you might want to stop when you get there!!" Umm the usual method for a continuous thrust propulsion device is that you accelerate for half the journey then turn the whole shebang around and decelerate for the other half. Theoretically, if you weren't worried about stopping, you could get there in much less than one month.
You accelerate half way there, then turn the ship over and decelerate the rest of the way.
I don't suppose very much of the ISS or any other space craft is made of anything that would be attracted to a magnet.
they got here in 1898, 1938, and 1953, yet no-one remembers a giant hydrogen cannon firing cylinders at us from Mars? well, apart from me and amanfrommars...
...Who had a very powerful magnet.
Seems some people never grow up :)
(one for the PBR watchers)
Before all you "I'm Going to Mars" freaks get excited, remember;
1. 38 days is already without slowing down (Steve), if you want to slow down you're looking at 3 months
2. This is for a tiny unit (pretty much just the engine), proof of concept really
3. A manned craft would need to be huge in comparison, sheilding, biosphere, water/air recyclers, how many will you send?
4. You'd still need convential boost for manouvers
5. You'd need a nuke to power it
6. Don't even think about landing a human on Mars, gravity is more than twice the moon lands with a bigger bump, needs a harder shove to get off again (and there aint no landing strips).
OK, so given we're unable to land on the moon and get back anymore (and it was pretty close last time), you'd need to build something damn big (or build an ISS at Mars over several years, then send someone and hope it still works), given that launch capability is pretty much nil, do you think it will happen?
OK, still think it will happen? so imagine the trillions of dollars it will cost, what will be get out of it? nothing? anything?
Cool engine, but saving a few months to get to Mars? meh
I doubt very much that a superconducting magnet is going to help protect astronauts very much if the thought that it would deflect charged cosmic rays in the manner of the Earth's magnetic field. The Earths' magnetic field effectively operates over distances of several tens of thousands of km and can deflect charged particles. It seems very unlikely to me that a man-made magnetic field is going to extend anything like far enough to provide much protection. I suspect it is designed to generate a very powerful magnetic field extending over a short distance.
Now just put Heim theory to practise, and then warp out!
Did no-one think to strap it to their heads?
the UK for showing that we do still have the brains. Pity we don't have a Govt with a brain between them.
I believe some of the previous probes have used atmospheric braking once they reached the target. They orbit in an elliptical path grazing the atmosphere each time and slowing down till they reach the desired speed and altitude which moves in to a nice circular orbit. Not much need for huge thrusters to slow down using that method.
The VASIMR system isn't the first high-energy rocket to be designed for getting people to Mars quickly. It isn't even the most efficient design; that goes to the Cold War Project Orion vehicle.
The highest energy density fuel known is of course nuclear fuel, and the best way of utilising this if you just want a big rocket is to use nuclear explosives. Project Orion was a huge, shielded, damped rocket ship which if it had ever been built would have flown by means of a mechanism that threw nuclear bombs behind it.
As it happens, the project got quite a long way towards completion, including shielding designs, test models being flown and the all-important work on how to mass produce nuclear bombs in the thousands quickly, safely and cheaply. The project never flew, because of the incredible amount of grief and upset it would have caused from fallout and irritated Soviet generals. Had it flown, it would have worked quite well as transport save for being quite incredibly polluting and extremely unpopular wherever it went.
However it is a very good idea to keep in mind that the USA still has the knowhow to make lots and lots and lots of nuclear bombs very quickly, so trying to start a global jihad to wipe out the infidels ain't a great idea, if you take my meaning...
i know the basic logic seems to be "You accelerate half way there, then turn the ship over and decelerate the rest of the way" but what is the speed of the planet versus the speed of this new engine ?
if you want to intercept a car traveling at speed X an the interceptor can travel faster in that same direction then you need to slow down OC, but is this new engine thrust far greater than the planet speed?
if it is faster, then wouldnt you just aim to be at the right place infront of the planet trejectory , and have the planets gravity pull on your interceptor to slow it right down?.
“It's cosmic radiation, which can do seriously nasty things to your body with long-term exposure. “
Perhaps. Incidently neither Gamma nor X-rays (being electromagnetic waves) are deflected by magnets. However most of the presentations I have seen from NASA (particularly for Virgin Galactic style LEO space flight and interplanetary trips) focussed on the solar wind and solar flares as “Space weather.” While Galactic Gamma Rays can be powerful, for human flight the day to day bursts from our nearest star are quite dangerous enough. 20MeV Protons ( a fairly regular solar emission) are lethal at the levels of a sunspot even in LEO. Fortunately both Electrons and Protons, being charged particles could be deflected by a large magnet (in different directions)
The only human exploits beyond the magnetosphere have been the Moon missions, and those only lasted a few days so no big deal.
NASA did risk analysis on the chance of an Apollo flight being caught in an unexpected solar flare. Note this was at a time when there were no early-warning probes in solar orbit (there is one now, but its about 15 years old and there seems no prospect of getting it replaced. A pity as it would give enough warning of a big flare at around 15 minutes to greatly reduce power grid damage).
There was a significant risk but NASA aimed to schedule the flights (I think solar activity is on a 26 day cycle) to reduce it. Capsule design took radiation shielding properties into effect but depending on when a large flare hit they could have died.
With thanks to NASA's space weather girl.
I believe this is usually called "lithobraking".
"What about stopping?
By Tim Greenwood Posted Tuesday 7th July 2009 11:27 GMT
It's all very well accelerating at ridiculous speeds to get to Mars in just over one month instead of a year. But I hope the brakes are good because you might want to stop when you get there!!?
The NASA profile for a VASIMR Mars mission would be as follows;
1. Accelerate in Earth orbit then slingshot into a Mars transfer trajectory with the VASIMR still thrusting.
2. At the halfway point shut down the VASIMR, rotate the ship 180 degrees then re-start the VASIMR. Its thrust decelerates the ship on the way to Mars instead of doing a big burn just as you approach Mars.
3. Enter Mars orbit in a decelerating spiral, the opposite of what was done in Earth orbit. The end of this would result in the ship being in a stable Mars orbit.
4. The return to Earth would be the opposite.
Estimates are that, depending on the mission parameters, as little as a 35-45 day trip to Mars instead of the several months to a year or more using chemical rockets.
Impacting a planet's hard, rocky surface tends to result in stopping within a short distance. Not much use if a return trip is planned, though.
This is a high velocity accelerator and you would not want to stand in front of it when in use. (Oh dear where did that hole come from. Must be moths.)
The thing is that unlike high mas low velocity rockets the particle beam is focussed and will strike anything within reasonable distance without reducing thrust. The point is that there are many low orbit object which could be deflected by the beam of the ISS thruster. We know where most of these objects are at the present. What about the future? Highly dangerous if you ask me.
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