Could just pure use of electricity and no other form of burning fuel be used to propulse a vehicle? Or even a spaceship perhaps?

Travel to Mars in 39 days

Amazing how technology from Star Trek could become a reality huh? So who says a man can't dream?

Seeing as they propose to use solar power as their fuel, that would require highly efficient panels and a large number of them... I'm dubious as to whether they will be able to power this properly.

I'm more interested in solar sails as a better method of propulsion since they do not require fuel (other than getting into orbit, reentry).

Would a trip to Mars be feasible with solar sails? I was under the impression that solar sails take a long time to accelerate, and "nearby" distances like Mars might not benefit from it?

What you're talking about is Ion Propulsion.

Ion Propulsion is not propulsion using electricity *only*. There still is fuel.

In normal rockets, we burn tonnes of liquid hydrogen and liquid oxygen to produce a thrust forward. Ion propulsion is slightly different.

In ion propulsion, instead of burning hydrogen and oxygen, we take a kind of gas like Xenon and ionise it using lots of electricity. We only use a tiny bit of gas each time, so the gas lasts very long unlike the Hydrogen+Oxygen combination, but since we use so little, we need to accelerate the gas to very high velocities out the back of the space to generate enough thrust.

The faster you can accelerate the molecules out, the more thrust you get.

There are limitations though. The lifetime of an ion engine is not only limited by the amount of propellant it can carry, but also how long the engine can maintain it's structural integrity. Apparently, the ions will cause erosion in the engine as the engine operates.

Wikipedia has a good explanation on all of this:
http://en.wikipedia.org/wiki/Ion_propulsion

This post has been edited by DeniseLau: Oct 27 2009, 11:55 PM

But ion propulsion's major disadvantage is its small thrust.
It's advantage is that it can maintain that maximum thrust for a very long period, thus enabling the spacecraft to achieve potentially higher velocities than a conventional chemically powered spacecraft.
So I doubt that the 39 day mission is plausible

putting the cart before the horse. find a way to bring/construct the spacecraft to orbit, then we'll talk about propulsion system

but yes, theoretically 39 days is possible

It can always be piggy-backed on a shuttle or can be launched and assembled in stages. The engine won't be large, the space is needed for human ergonomics.

compare with the time/energy/effort/cost of assembling the ISS (which is still technically not complete as new module/equipment is still going up.

We're talking about the engine used to provide thrust to a spacecraft traveling to Mars. So we're assuming that the capability of launching the payload from the surface of the Earth has already been realised.
And technically the ISS is already complete. Those new modules and equipments are just to supplement aging equipments and other what nots.

what?

first u must have the engine, then u figure out where to build the car. no point having a factory when u dont even have an engine.

when this engine is only capable of running on highway, you must 1st figure out how to get the car to the highway. otherwise the car with new engine will only stay in your garage

so u're saying that even if u dont have the engine, we should figure out how to get a non-existing object on the highway first?

by the way, u're talking about a problem that already has a solution. that's what the multi-staged thrusters are for. it's just not as efficient as ion engine, but it still solves the problem.

merely pointing out that without a viable method of constructing/transporting spaceships to orbits, achievement such as these, while wonderful in their own rights, should not result in us going "booyah! interplanetary/interstellar travel on the horizon!"

The problem now is that we DO have viable methods of transporting vehicles into space. And now we're not talking about whether interplanetary commute being on the horizon. We're talking about the claim that commuting to Mars is possible within 39 days using ion thrusters.

space shuttle is due to be retired. apollo type rocket info was lost (shocking). new class of cheap earth/space transport method is currently in development but has hit numerous problems. the largest space nation (USA) is getting less and less space-capable.

ion thrusters capable of 39day trip does not mean 39day trip is possible with current technology

Well I certainly favour ion engine over stuff like Orion propulsion method, to be honest. (seen in movie Deep Impact, used by Messiah)

china is surpassing the USA in the current space race. they're more than able to land humans on the moon, as well as sending the first manned trip to mars. japan, korea and ESA is close behind them. india and pakistan is also ready to join the race.

so NASA might not be able. but others still can.

it doesnt matter if 39day is possible or not TODAY. that's not the issue. when humans first discovered flight, they didnt stop knowing that they would never break the sound barrier until 50 years later, right?

The world does not revolve around the US.
Although NASA has encountered a lot of problems in recent times, the Europeans launches are getting more and more reliable, with more and more private companies joining in the business. And the only way private companies can complete with national government-backed space bodies is to constantly come up with innovative and reliable methods of launching rockets into space, which solves your problem of first getting the spacecraft into orbit, just in case you forgot what your argument was about.

1. i'll believe it when i see it. (china to moon/mars)
2. no objections there. later rather than sooner though

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Added on October 30, 2009, 12:43 amno arguments. just discussion.

the current space exploration environment does still revolve around NASA. who else do you think got all those private venture to develop space tech? CERN?

as of today, there is no reliable way of getting large objects into orbit other than with the shuttle. other countries are only launching satellites and capsules. capsule is fine for trip to moon. but for longer distance/time period, large vehicle and more living space is needed.

to recap my points. yes, 39 days trip to mars maybe possible by calculations and simulation. but a more current issue of getting such a craft to orbit need to be solved before anything practical can be tested.

otherwise its only academic even if you can come up a 7 day travel period, because for all practical purpose, you are still stuck on earth.

its a wonderful discovery but looking at the larger picture, today, that discovery dont mean much.

This post has been edited by lin00b: Oct 30 2009, 12:43 AM