In-space testing
One way to make good on the promise of VASIMR is through in-space testing.
This week, Chang-Diaz heads for NASA's Marshall Space Flight Center. He is proposing that a multi-propulsion platform be attached to the International Space Station.
"We could test every one of the electric propulsion concepts that are on the table now, using the station as a laboratory," Chang-Diaz said. Doing so could save money and provide other benefits. Using vacuum test chambers on the ground is expensive. Further, each chamber has a mind of its own, introducing effects that can mask true levels of engine performance, he said.
Testing the VASIMR engine and its electric propulsion kin on the station would also help solve a serious and continuing problem up there -- reboosting the orbiting outpost into its proper position now and then after the atmosphere pulls it down.
"You'd be pushing on the station and overcoming the drag of the atmosphere," the astronaut said, adding that the process would create a more favorable level of microgravity for onboard science experiments.
A veteran of seven space shuttle flights, Chang-Diaz spotlights the utility of the giant complex: "The station is a beautiful laboratory. I was there. I saw it on the outside too. The station is something we can really take advantage of right now."
Nudging a nuisance
VASIMR is being looked at as candidate technology for other missions as well.
Last year, Chang-Diaz took part in a workshop on deflecting asteroids. Held at JSC, the workshop's goal was to brainstorm scenarios for altering an asteroid's orbit, perhaps using VASIMR powered by nuclear reactor.
The gathering included asteroid experts, engineers, current and former astronauts, and a Deep Space Network executive. Several participants advocated a nuclear electric plasma rocket as the best choice for a first demonstration mission.
How best to couple the engine to an asteroid was discussed. By exerting a continuous force -- on the order of one Newton, typical for a plasma engine powered by a 100-kilowatt electric source -- driving an asteroid was described as pushing a beach ball across a swimming pool using your nose.
Any asteroid deflection test using the rocket has spinoff advantages too.
For one, such a shakeout would be useful in flight-qualifying the technology for a suite of other missions, from supporting human flight to Mars to a fast-track flight to Pluto and beyond, into the Kuiper Belt.
Asteroid deflection work
A strong supporter of VASIMR is astronaut John Young, noting that the engine is ideal for planetary defense work. "This is new progress," Young said. "It's a great motor."
Young said JSC experts and others have begun discussing the idea of using VASIMR to shove a 230-foot (70-meter) asteroid around. Such practice runs could help hone scientists' ability to nudge potentially Earth-threatening asteroids out of harms way in the future, he said.
No asteroids are known to be on collision courses with Earth, but many experts have said planning should begin now for a method to destroy or deflect one that might one day be found to target the planet.
Young said VASIMR had its own near miss when the project was nearly cancelled. As Chang-Diaz and other crewmembers sat tucked inside Endeavour ready to start STS-111's climb toward the International Space Station in early June, NASA managers were ready to close down the project.
"The day he was going to launch they were going to shut his motor down and take away his people working on it," Young said. VASIMR was saved, but the project was given funding just through the rest of the year, he said.
"I think it's the motor that we ought to have," Young said. "If we're seriously talking about deflecting asteroids, that's the motor that will do it."
Eternal optimist
Protecting Earth from asteroids. Sending humans Marsward. Dispatching spacecraft outward into the depths of space -- these and other missions are constructive ways of using VASIMR technology, Chang-Diaz said.
VASIMR's promising attributes continue to be on trial. Future funding is in question, with the novel contraption entering a NASA limbo land of peer review later this year.
A thumbs-up would likely mean more cash would be pumped VASIMR's way to help harness the technology.
"We have been reviewed before. We'll do our best and go along. This is the way the game is played. And we want to be part of the team," Chang-Diaz said.
"I'm an eternal optimist," he concluded.
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