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 within five years
if financial support remains consistent, he said. The project
will be among the topics during the sixth annual NASA Advanced
Concepts Institute meeting Tuesday and Wednesday at the Grand
Hyatt Hotel in Seattle. The meeting is free and open to the
public.
Winglee acknowledges that it would take an initial
investment of billions of dollars to place stations around the
solar system. But once they are in place, their power sources
should allow them to generate plasma indefinitely. The system
ultimately would reduce spacecraft costs, since individual
craft would no longer have to carry their own propulsion
systems. They would get up to speed quickly with a strong push
from a plasma station, then coast at high speed until they
reach their destination, where they would be slowed by another
plasma station.
"This would facilitate a permanent human presence in
space," Winglee said. "That's what we are trying to get to."
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For more information, contact Winglee at (206) 685-8160 or
winglee@ess.washington.edu
More details on advanced propulsion concepts can be found
at: http://www.ess.washington.edu/Space/propulsion.html