The VASIMR (Variable Specific Impulse Magnetoplasma Rocket) is a state-of-the-art rocket design that uses plasma for rocket propulsion. Chang-Diaz developed the concept of the VASIMR in 1979, shortly following his graduate research at MIT in fusion and plasma-based rocket propulsion. After being selected as an astronaut in 1980, Chang-Diaz served on seven different shuttle missions. After retiring in 2005 from NASA, Chang-Diaz formed Ad Astra Rocket Company to develop his concept of the VASIMR.
Ad Astra Rocket Company in Costa Rica is currently developing the VX-200, a full-scale prototype of the VASIMR engine intended for ground testing. The company intends to complete the prototype by early 2008. Following the test, the company will begin preparations for the VF-200-1, the first flight unit. Ad Astra Rocket Company hopes to send the VF-200-1 into space by late 2010. The VASIMR technology could be very useful in the near future for interplanetary space travel. The VASIMR design would be capable of reducing the trip to Mars to less than four months, whereas current chemical rockets take around eight months..