From Earth to Mars in 39 Days?

Imagine being able to travel from Earth to another world within your life time. Now imagine if it was possible to do so without having to spend months or even years in space. This is not science fiction. It may soon become science fact, thanks to NASA and the Ad Astra Rocket Company announcing a deal that will test a scale model of Ad Astra’s new Variable Specific Impulse Magnetoplasma Rocket (or VASIMR) on the International Space Station.

Instead of heating chemicals and pushing the gas through metal nozzles as current rockets do, Vasimr will work by collecting energy from the sun using solar panels, which will then generate radio waves to heat argon gas into plasma. Once the argon gas has been converted into plasma, Vasimr will then run an electrical current through a series of superconducting magnets to create a magnetic field to direct the plasma as it’s pushed out of the engine, which generates thrust. Not only would Vasimr be far more efficient than chemical rockets, but it would also use a lot less fuel as well.

Ad Astra’s director of development, Tim Glover, said in August 2006 that “[t]he first application [they] see a market for is hauling things from low-Earth orbit to low-lunar orbit.” The reusable Vasimr engine would be capable of hauling around 2,000 pounds of cargo, or twice the load of similar sized chemical rocket engines. While each trip would take about six months and be incapable of sending people to the moon, depending on how long the solar cells last each Vasimr powered ship would be able to make on average six round-trip flights to the moon which could then enable NASA to store fuel for a return trip to Earth.

Testing VASIMR On the International Space Station

Ad Astra hopes to launch the plasma engine in 2011 or 2012, which would then be assembled at the International Space Station by spacewalking astronauts. Once the Vasimr VF-200 propulsion system is attached, it will either be run from inside the space station or remotely from ground-based control stations. The engine will operate at 20 kW using hydrogen gas (a waste product generated by the space station) instead of argon, and will be restricted to pulses of about ten minutes at a time - slightly less than the push exerted by a weight of one pound of gravity here on Earth.

NASA and Ad Astra plan to use the International Space Station as an orbiting laboratory to test how the Vasimr plasma engine handles and performs in the vaccum of space without having to spend the extra time and money necessary developing and flying communications systems, power supplies and other essential services to aid their tests. If successful, the new rocket engine will eliminate the need to ferry large loads of rocket fuel currently used by the chemical boosters to keep the International Space Station’s orbit from decaying and falling to Earth.

So, what can we do with a Vasimr Plasma Engine?

Let’s assume this test passes with flying colors. The first thing that Ad Astra will likely do (and they have already said as much) will be to use the Vasimr plasma rocket engine to haul (non-human) cargo from a low-Earth orbit to a low-lunar orbit. Vasimr is not going to replace the Space Shuttle since it lacks the thrust to get off the ground. Instead, it will likely be used to compliment the Orion Crew Exploration Vehicle. Orion would presumably be used to ferry between four and six astronauts from Earth to a Vasimir-powered spacecraft, which would then ferry the CEV to either the moon or Mars. Once the Vasimr plasma rocket reaches its destination, the CEV could detach and head towards the lunar or Martian surface.

Of course, we would need a lot more power to effectively use a Vasimr-powered rocket, and solar cells just won’t cut it in deep interplanetary space. So what would we use? A nuclear reactor, of course. We woudln’t need a large one; in fact, the nuclear reactor found on the Los Angeles class attack submarine would be the ideal size to power a Vasimr plasma engine. Not surprisingly, Dr. Franklin Chang Diaz, the CEO of Ad Astra and a seven-time Space Shuttle astronaut, agrees that nuclear fission would be the best available solution. His analysis has suggested that a 12-megawatt Vasimr spacecraft could reach Mars in as little as 39 days, a far cry from the nine months it currently takes to send unmanned craft from Earth to the red planet.

References

• NASA Administrator Hails Agreement with Ad Astra
• NASA and Ad Astra Rocket Company sign Agreement for flight test of the VASIMR rocket engine aboard the International Space Station
• Ad Astra Vasimir Rocket
• Variable Specific Impulse Magnetoplasma Rocket (VASIMR)
• Plasma Rocket (This is the YouTube video embedded above.)
• Propulsion Systems of the Future (NASA)