In an old shoe distribution center just down the road from Johnson Space Center in Houston, TX, rocket scientists are developing the engines that may one day propel giant landers to search for life on Europa or hurtle the first human missions to across the void to Mars.  Once part of NASA’s long-term technology development program, the Ad Astra Rocket Company is now a private space propulsion lab headed by former NASA astronaut Franklin Chang Díaz.  On a recent trip to Houston I was privileged to be able to tour the lab and see where the future is being built.

Ad Astra is developing the VASIMR (Variable Specific Impulse Magnetoplasma Rocket).  They are developing a plasma rocket that shoots out super-hot exhausted that is controlled and directed by super-conducting magnets.  WOW.  The company is working with NASA to fly a full-scale prototype engine on the International Space Station in the next few years to refine their simulation models and confirm the output of the futuristic engine.

VASIMR diagram from Ad Astra

The building is unassuming to say the least.  It does not have a fancy glass and steel entryway, Tron-like glowing walls, or scenic views. Driving up, we were convinced we were in the wrong place. Inside the building, an open floor plan revealed a small reception area separated from a few modern work stations and a large conference room. The decor was sparse, a tasteful and eclectic mix of awards, spacecraft models, and signed Space Shuttle crew pictures from Chang-Diaz’s flights.

 It was nice. I was underwhelmed.  Ad Astra seemed like a light research facility–maybe they just did some CAD drawings or made nice artistic rendering of spaceships here?  Along one wall was a large aluminum box with two big holes at the top that turned out to be a full-scale model of the plasma engine they intend to fly up to the ISS. It was while looking at the box we noticed an odd sound.  To be honest it sounded something like the TARDIS landing (“whooosh-a, whooosh-a“). We passed through a set of doors at the end of the room and my day got MUCH better.

The first thing you’ll notice walking in the lab is the gigantic thermal vacuum chamber sitting in the middle of the room. At 15+ ft high, 35+ ft long and sprouting hoses, wires, tubes, portholes–THIS was evidence of the real work being done at Ad Astra. Plasma (the fifth state of matter!) is a highly energetic cloud of super-low-density atoms typically found in places like the sun. The vacuum chamber is needed to remove the dense air that would overpower the plasma engine exhaust.

Ad Astra thermal vac chamber

Ad Astra scientists in front of the AARC 150 m3 vacuum chamber. Credit: Ad Astra Rocket Company

Overhead cranes, scaffolding and stands all attested to something big  being constantly tweaked in the lab.  A double row of monitors and workstations that serve as “Mission Control”  during the scaled-down plasma engine runs stood between us and the chamber.  The sound of cryogenic cooling pumps (disappointingly not a TARDIS!) constantly echoed through the room, dropping the internal temperature of the test chamber low enough to freeze any gas molecules remaining inside create a better vacuum for the tests.

We peered into the chamber and could see the row of instruments set in the path of the engine exhaust to analyze the force of the plasma and the conditions inside the plume.  Although the engine produces only about 1-lb of force at full power, the plasma is so energetic that it eats away at the instruments (we saw some of the retired pieces–yikes!).

the VX-200 operating at full power with argon propellant.  Credit: Kat's Photography

The VX-200 operating at full power with argon propellant. Credit: Kat's Photography

The plasma is so hot that no material can actually contain the exhaust once it is heated. Magnetic fields are used direct the plasma and funnel it out of the nozzles (If you’re thinking of the antimatter containment fields from Star Trek–you’re right on the money!).  To create the strong magnetic fields, Ad Astra can either use extremely expensive rare-earth high-temperature super conductors or use standard super-conducting magnets cooled by liquid nitrogen.  In the lab, they use the cheaper magnets (similar to those in an MRI). In space they’ll be using the expensive, smaller magnets to get the job done.

(Fun fact: there are VERY few of the rare-earth high-temperature super-conducting magnets because they are prohibitively expensive to make. Labs rent one the few that do exist when they need to run specific tests! )

The plasma engine tests require so much electricity that Ad Astra has an entire electrical substation inside the building to support their needs during a test run.  The city of Webster, TX,  even upgraded their power management infrastructure to support the additional load on the grid!

Ad Astra scientists operating the VX-200 rocket. Credit: Kat's Photography

Surrounded by all of the support equipment, specialized data collection tools, and sophisticated monitoring tools, I had the surreal feeling of being inside the world of some sci-fi show. (Surprise!  The lab has been used as a set for some filming!  Too cool.)  Although I’ve seen somewhat similar setups at NASA facilities, it was totally different to see a for-profit company working on advanced engine testing.  REAL rocket science being done by the PRIVATE industry!  It finally dawned on me that I was seeing the commercial space industry that has been so debated lately. This was not just a CAD drawing or set of equations being crunched by someone with a PhD in plasma physics (though they have several on staff!). No, this is an operational test facility building and testing game-changing technology.  Today.

A 2MW solar powered lunar tug concept using 4 VASIMR® engines.

I sincerely appreciate the opportunity I was given to tour the lab and learn about these amazing plasma rockets. I look forward to seeing the VASIMR prototype on the space station–and to seeing it operating on long-distance spacecraft in the future!


You can also check out more about Ad Astra Rocket Company in the NASA360 podcast

>>MUCH THANKS to Rachel Hobson for instigating the tour! She rocks.


>Updated August 22, 2010: New VASIMR pic, corrections on magnets and energy usage per Ad Astra.