VASIMR VX-200 plasma rocket achieves full power efficiency milestone

The plan is to do a lot better. This is incremental development.

The mooted mars mission ship needs 12 MW propulsion (3 x 4MW VASMIR engines) with exhaust velocity variable between 30 and 500k/s.

More coin = faster progress. Its not exactly been a high priority up till now.

Picture of it found here.

web.mit.edu...

Originally posted by RedGolem
I can see where it would work on the moon, but because of the gravity and atmosphere on Earth I would not have thought it possible. Since NASA is looking into it I hope the problems will get worked out. Launching a vehicle into orbit with out the need for a booster is something that has speculated on for a long time.

I don't know if you read that article, but NASA said they'd need to get it to 10 times the 60mph speed of a roller coaster track. If you do the math that's only 600 miles per hour, which is nothing compared to the 25000mph escape velocity for Earth.

So the Rail would still only be one stage of a multi-stage approach, but they wouldn't need the disposable rocket stages. "Stage one" could be the rail, and "stage two" could be a hypersonic plane launched from the rail carrying the payload. When the hypersonic plane nears orbit, it could then deploy the payload (such as this VASIMR) and return to Earth. It will indeed be cool if they can get it working, but it will be challenging.

I don't see how the rail by itself (without the hypersonic plane launch) could make a payload reach escape velocity from Earth, but it could on the moon as you said.

reply to post by Arbitrageur


Arbitrageur
I did not read the entire article, just that it would need to get to ten times the speed of a roller coaster. I also am not farmiler with the physics involved, but now you have explained some of that for me any any one else interested, thank you.
Or so the rail just takes the place of the first booster, then a reusable drone will take place of the second. All in all a rather good idea I do think.
Again thanks for explaining.

Originally posted by justwokeup


The mooted mars mission ship needs 12 MW propulsion (3 x 4MW VASMIR engines) with exhaust velocity variable between 30 and 500k/s.

More coin = faster progress. Its not exactly been a high priority up till now.

Picture of it found here.

web.mit.edu...

That is a great link Just.
thanks for posting it.
star

Originally posted by Arbitrageur

Originally posted by RedGolem
I can see where it would work on the moon, but because of the gravity and atmosphere on Earth I would not have thought it possible. Since NASA is looking into it I hope the problems will get worked out. Launching a vehicle into orbit with out the need for a booster is something that has speculated on for a long time.

I don't know if you read that article, but NASA said they'd need to get it to 10 times the 60mph speed of a roller coaster track. If you do the math that's only 600 miles per hour, which is nothing compared to the 25000mph escape velocity for Earth.

So the Rail would still only be one stage of a multi-stage approach, but they wouldn't need the disposable rocket stages. "Stage one" could be the rail, and "stage two" could be a hypersonic plane launched from the rail carrying the payload. When the hypersonic plane nears orbit, it could then deploy the payload (such as this VASIMR) and return to Earth. It will indeed be cool if they can get it working, but it will be challenging.

The escape velocity would need to be 17,000 to 18,000 mph to get the craft in orbit. Once in space, the plasma engine is fired and after several orbits, (hopefully) escape velocity is then achieved. A thirty mile long rail situated on the equator would allow the craft to gradually build speed and not pushing the cargo and occupants out the rear from inertia. A rocket would then be needed to further propel the craft to orbit. If the rail system could get the craft to 12,000 mph the rocket wouldn't have to be that big. Baby steps... Haven't done the math yet to determine the height the rail would have to be at final deployment. It might have to be turned up on the end like a British aircraft carrier to go to (I'm guessing) 75 to 90 degrees. T'would be a lot of stress on the end that would have to be compensated for.
If the plasma engine was more efficient, then only the plasma rocket would be need to achieve orbit after being rail fired.

I don't see how the rail by itself (without the hypersonic plane launch) could make a payload reach escape velocity from Earth, but it could on the moon as you said.

A pound of thrust is not very much for that kind of input, but it can maintain the output for a longer period of time. It will take a long time to get up to max speed, and also it will take a long time to slow down too. This is just a test model and I think they are also looking at building a much larger engine for use in space. This is just a learning experience so they can move on to bigger and better things in the future.

i never understood why we cant just copy nature...

blogs.discovermagazine.com...

spores that fire off at 180000 G ... thats right, not a type one hundred and eighty thousand G

i love man made stuff, but nature still manages better. if we could copy this somehow we could launch sattelites for the cost of water pressure and a sattelite!

Originally posted by okamitengu
i never understood why we cant just copy nature...

spores that fire off at 180000 G ... thats right, not a type one hundred and eighty thousand G

Spores are pretty robust and apparently can survive those G-forces. A few hundred Gs can kill a person so forget about using it for a manned mission to Mars, so the Space Gun which would produce 1800 Gs isn't suitable for humans. Even satellites would really have to be ruggedized to withstand G-forces like that, and atmospheric drag is still a problem whether you're talking about spores or space guns.

So copying nature might be fine if we want to launch spore like orbits, but probably not for launching things into orbit or to Mars.

Thanks for the interesting article though!

damn, all good points. i knew we couldn't throw people up but i didn't think about friction and drag on sattelites.

this is why i keep coming back here. contribute, learn, and teach all at the same time.