The VASIMR is a state-of-the-art rocket design that uses plasma for rocket propulsion. Chang Díaz developed the concept of the VASIMR in 1979, shortly following his graduate research in fusion and plasma-based rocket propulsion at the Massachusetts Institute of Technology. After being selected as an astronaut in 1980, Chang Díaz served on seven different shuttle missions, a space record that he shares with astronaut Jerry L. Ross. After retiring in 2005 from NASA, Chang Díaz formed Ad Astra Rocket Company to develop and commercialize the VASIMR technology. Ad Astra completed a formal Preliminary Design Review on the VF-200 engine with NASA in June 2013. This is the initial major design milestone on the path to flying a VF-200 on the ISS.
200 kW Engine
Ad Astra Rocket Company developed the VX-200, a full-scale prototype of the VASIMR engine intended for ground testing. The company successfully tested the prototype in September 2009. Following the test, the company will begin preparations for the VF-200-1, the first flight unit. The VASIMR technology could be useful in the near future for interplanetary space travel. The VASIMR design would be capable of reducing the trip from Earth to Mars to less than four months, whereas current chemical rockets would take around eight months for one-way transit, making the round-trip mission longer than 2 years. A nuclear-powered VASIMR engine could shorten the round-trip in-flight time into under five months, while smaller scale solar powered engines could tug satellites through different orbits and deliver loads to the moon. , the company is aiming to offer the technology for space tug missions to help "clean up the ever-growing problem of space trash." , a recent test phase of the VX-200 has demonstrated a ten percent increase in efficiency at intermediate levels of specific impulse, indicating that an operational version would both increase payload mass and decrease trip times. The "efficiency improvements were achieved through design improvements in critical engine components, 'fine-tuning' the radio-frequency power system settings, and upgrades to the software that controls the engine during startup and firing." The company continues to aim for a "prospective 2015 test flight of a Vasimr prototype, either to the International Space Station or on a free-flyer, for three years of in-space characterization." , Ad Astra completed a formal Preliminary Design Review on the VF-200 engine, as a critical milestone on the development pathway to testing the VF-200 on a multi-month test on the International Space Station. A number of long-duration engine firings are planned.