To Mars and Back in Ninety Days

paltemalte writes "A new means of propelling spacecraft being developed at the University of Washington could dramatically cut the time needed for astronauts to travel to and from Mars and could make humans a permanent fixture in space. In fact, with magnetized-beam plasma propulsion, or mag-beam, quick trips to distant parts of the solar system could become routine, said Robert Winglee, a UW Earth and space sciences professor who is leading the project."

Comments

Re:thoughts

[mirko]

OK, this was slashdotted but I eventually got through and it answered some other questions... Here's the text for the less lucky people...

Oct. 14, 2004 |

Science and Tech
New propulsion concept could make 90-day Mars round trip possible
FROM: Vince Stricherz vinces@u.washington.edu206-543-2580
John Carscadden, University of Washington In this artist's conception, a plasma station (lower left) applies a magnetized beam of ionized plasma to a spacecraft bound for Jupiter.

A new means of propelling spacecraft being developed at the University of Washington could dramatically cut the time needed for astronauts to travel to and from Mars and could make humans a permanent fixture in space.

In fact, with magnetized-beam plasma propulsion, or mag-beam, quick trips to distant parts of the solar system could become routine, said Robert Winglee, a UW Earth and space sciences professor who is leading the project.

Currently, using conventional technology and adjusting for the orbits of both the Earth and Mars around the sun, it would take astronauts about 2.5 years to travel to Mars, conduct their scientific mission and return.

"We're trying to get to Mars and back in 90 days," Winglee said. "Our philosophy is that, if it's going to take two-and-a-half years, the chances of a successful mission are pretty low."

Mag-beam is one of 12 proposals that this month began receiving support from the National Aeronautics and Space Administration's Institute for Advanced Concepts. Each gets $75,000 for a six-month study to validate the concept and identify challenges in developing it. Projects that make it through that phase are eligible for as much as $400,000 more over two years.

Under the mag-beam concept, a space-based station would generate a stream of magnetized ions that would interact with a magnetic sail on a spacecraft and propel it through the solar system at high speeds that increase with the size of the plasma beam. Winglee estimates that a control nozzle 32 meters wide would generate a plasma beam capable of propelling a spacecraft at 11.7 kilometers per second. That translates to more than 26,000 miles an hour or more than 625,000 miles a day.

Mars is an average of 48 million miles from Earth, though the distance can vary greatly depending on where the two planets are in their orbits around the sun. At that distance, a spacecraft traveling 625,000 miles a day would take more than 76 days to get to the red planet. But Winglee is working on ways to devise even greater speeds so the round trip could be accomplished in three months.

But to make such high speeds practical, another plasma unit must be stationed on a platform at the other end of the trip to apply brakes to the spacecraft.

"Rather than a spacecraft having to carry these big powerful propulsion units, you can have much smaller payloads," he said.

Winglee envisions units being placed around the solar system by missions already planned by NASA. One could be used as an integral part of a research mission to Jupiter, for instance, and then left in orbit there when the mission is completed. Units placed farther out in the solar system would use nuclear power to create the ionized plasma; those closer to the sun would be able to use electricity generated by solar panels.

The mag-beam concept grew out of an earlier effort Winglee led to develop a system called mini-magnetospheric plasma propulsion. In that system, a plasma bubble would be created around a spacecraft and sail on the solar wind. The mag-beam concept removes reliance on the solar wind, replacing it with a plasma beam that can be controlled for strength and direction.

A mag-beam test mission could be possible

Shipping the fuel to Mars = $T

[The Fun Guy]

The big "breakthtrough" here is to decouple the propulsion system (the plasma beam) from the spacecraft. That makes the craft smaller and lighter since it doesn't have to move all that fuel around.

HOWEVER...

This system requires having another plasm beam generator to "catch" the spacecraft and slow it down with another plasma beam. That means not only sending the generator platform to Mars, but also all of the material from which to make the plasma (most likely nitrogen or one of the heavier noble gases). The generator platform needs a power source capable of sustaing the creating and acceleration of the plasma beam, which means nuclear, and a fission nuclear reaction, not radiothermic generation. All of that means a technically complex space station, with people to keep it running. To have such a system in Earth orbit would be tough enough. The cost and difficulty of shipping all of that material out to a Mars orbit, and maintaining it so it will be ready to deccelerate an incoming spacecraft would be Absolutely Enormous.

Re:Sign me up...

[tgd]

No, thats not actually why DeBeers is so keen to do that.

Diamond is one of the most common gemstones in the world. It would have virtually no value if a) DeBeers hadn't pulled the greatest marketing spinjob in history convincing people today that diamond rings are a centuries old wedding tradition, not a decades old one and b) they didn't warehouse them.

DeBeers has warehouses of bins, floor to ceiling of diamonds they keep off the market to artificially inflate their value. By controlling access to virtually all the mines that are econimical to exploit, they ensure competitors with access to diamond deposits will not flood the market with cheap ones.

Re:This is fine and well, but...

[G00F]

We actualy have from 3-5 moons. The Moon that you know of is the fifth largest in the whole solar system. Kinda big, infact it is more of a planet with a shared orbit than it is a moon. It is to big, and affects earth to much (1/3 the size of earth) to be considered a satalite. However, since people have the "earth is flat" syndrome, people will always know earth has one moon, etc.

http://www.space.com/scienceastronomy/solarsyste m/ second_moon_991029.html

Re:This is fine and well, but...

[Christopher Thomas]

I've never understood why a shuttle takes off from a completely vertical position. I mean, doesn't it take the greatest amount of force to set an object in motion, rather than keep it going?

I'm not sure where this idea comes from.

Any given acceleration requires the same amount of force no matter how fast you're going. F = ma.

When you're moving in an atmosphere, you have to add force to counter air resistance as well, which goes up roughly as the square of airspeed.

The shuttle boosts upwards to get out of most of the atmosphere as fast as it can. Then it thrusts sideways, because it's sideways velocity that puts you in orbit. Taking off at an angle would just mean there'd be that much more atmosphere to plow through.

Aerodynamic craft with air-breathing engines _might_ be able to derive benefit from being in the atmosphere, but the shuttle's a brick strapped on to a bigarsed rocket booster, so it doesn't.

Re:This is fine and well, but...

[roystgnr]

Any given acceleration requires the same amount of force no matter how fast you're going. F = ma.

That would be true if it wasn't for gravity and aerodynamics adding to F. Imagine a spaceplane with wings and with engines that can indefinitely deliver 1G of acceleration: If it tried to launch straight up, it would never make it off a launch pad, but taking off from a runway it could reach orbit, because it's lift to drag ratio (even hypersonically) could be much larger than 1.

This doesn't apply to the shuttle, though; the shuttle's L/D ratio is larger than 1, but the L/D for the stack as a whole is pretty much zero.