Resonance is achieved through a reduction of the magnetic field in this portion of the engine that slows the orbital motion of the plasma particles.
[4][6] In contrast to the typical cyclotron resonance heating processes, VASIMR ions are immediately ejected from the magnetic nozzle before they achieve thermalized distribution.
The superconducting electromagnets necessary to contain hot plasma generate tesla-range magnetic fields[11] that can cause problems with other onboard devices and produce unwanted torque by interaction with the magnetosphere.
Franklin Chang Díaz is Ad Astra's chairman and CEO, and the company had a testing facility in Liberia, Costa Rica on the campus of Earth University.
[15][failed verification] The 100 kilowatt VASIMR experiment was successfully running by 2007 and demonstrated efficient plasma production with an ionization cost below 100 eV.
[15][17] In contrast, 2009 state-of-the-art, proven ion engine designs such as NASA's High Power Electric Propulsion (HiPEP) operated at 80% total thruster/PPU energy efficiency.
[18] On 24 October 2008, the company announced in a press release that the helicon plasma generation component of the 200 kW VX-200 engine had reached operational status.
The remaining 170 kW of power was allocated for acceleration of plasma in the second part of the engine, via ion cyclotron resonance heating.
[19] Based on data from VX-100 testing,[11] it was expected that, if room temperature superconductors are ever discovered, the VX-200 engine would have a system efficiency of 60–65% and a potential thrust level of 5 N. Optimal specific impulse appeared to be around 5,000 s using low cost argon propellant.
[20] Between April and September 2009, 200 kW tests were performed on the VX-200 prototype with 2 tesla superconducting magnets that are powered separately and not accounted for in any "efficiency" calculations.
[21] During November 2010, long duration, full power firing tests were performed, reaching steady state operation for 25 seconds and validating basic design characteristics.
[23] In March 2015, Ad Astra announced a $10 million award from NASA to advance the technology readiness of the next version of the VASIMR engine, the VX-200SS to meet the needs of deep space missions.
NASA gave approval for Ad Astra to proceed with Year 3 after reviewing completion of a 10-hour cumulative test of the VX-200SS engine at 100 kW.
[27] In August 2019, Ad Astra announced the successful completion of tests of a new generation radio-frequency (RF) Power Processing Unit (PPU) for the VASIMR engine, built by Aethera Technologies Ltd. of Canada.
[33] In order to conduct an imagined crewed trip to Mars in 39 days,[34] the VASIMR would require a very high electrical power level.