A second test, conducted from July 12 to 16, successfully ran the engine for 88 hours at a power level of 80kW. Ad Astra anticipates conducting 100kW power level tests in the second half of 2021. Potential applications VASIMR has a comparatively poor thrust-to-weight ratio, and requires an ambient vacuum. Proposed applications for VASIMR such as the rapid transportation of people to Mars would require a very high power, low mass energy source, ten times more efficient than a nuclear reactor (see nuclear electric rocket). In 2010 NASA Administrator Charles Bolden said that VASIMR technology could be the breakthrough technology that would reduce the travel time on a Mars mission from 2.5 years to 5 months. However this claim has not been repeated in the last decade. In August 2008, Tim Glover, Ad Astra director of development, publicly stated that the first expected application of VASIMR engine is "hauling things [non-human cargo] from low-Earth orbit to low-lunar orbit" supporting NASA's return to Moon efforts. Mars in 39 days In order to conduct an imagined crewed trip to Mars in 39 days, the VASIMR would require an electrical power level far beyond anything currently possible. On top of that, any power generation technology will produce waste heat. The necessary 200 megawatt reactor "with a power-to-mass density of 1,000 watts per kilogram" (Díaz quote) would require extremely efficient radiators to avoid the need for "football-field sized radiators" (Zubrin quote). See also Comparison of orbital rocket engines Electric propulsion Helicon Double Layer Thruster Magnetoplasmadynamic thruster Nano-particle field extraction thruster Pulsed plasma thruster Space fission reactors Project Prometheus Safe Affordable Fission Engine Systems for Nuclear Auxiliary Power TOPAZ nuclear reactor References Further reading External links "Plasma Rocket" (Video). Brink. Science. December 18, 2008. NASA documents Technical Paper: Rapid Mars Transits with Exhaust-Modulated Plasma Propulsion (PDF) Variable-Specific-Impulse Magnetoplasma Rocket (Tech Brief) Advanced Space Propulsion Laboratory: VASIMR Propulsion Systems of the Future Emerging technologies Magnetic propulsion devices Plasma physics Rocket propulsion Ion engines