Ad Astra Rocket Company’s VASIMR® VX-200SS Plasma Rocket has
completed 88 hours of continuous operation at 80 kW at the
company’s Texas laboratory near Houston. In doing so, the
company establishes a new high-power world endurance record in electric
propulsion. The test also demonstrates the maturity of the VASIMR®
engine technology as a competitive option for high-power in-space
electric propulsion with either solar or nuclear electric power.
Electric rockets operating above 50 kW/thruster are considered
“high-power.”
The test began at 12:50 pm (CST) last Monday July 12 and ended Friday,
July 16 at 4:55 am (CST). The firing stopped only 12 hours shy of its
intended duration of 100 hours due to a spurious temperature sensor located
in the test support equipment and not on the rocket structure.
The rocket, however, was performing normally and all indications
were that, were it not for this faulty sensor, it would have met and
exceeded the 100- hour goal. Ad Astra believes the 88-hr test provides
objective and sufficient evidence that the VASIMR® engine has met the
intent of the high-power endurance goal set by NASA.
“The test is a major success, the culmination of years of trial-and-error
testing and painstaking attention to detail and a handsome reward for
the team’s tenacity and dedication,” said Franklin R. Chang
Díaz, Ad Astra’s chairman and CEO and a decorated former NASA
astronaut. “With a new set of engine modifications already in
the manufacturing stage, we’ll now move to demonstrate thermal
steady state at 100 kW in the second half of 2021,” he added.
The VASIMR® engine is unique in that it retains the high power of a
chemical rocket but with ten times the fuel efficiency. As such, it is
an excellent candidate for a host of applications, ranging from
high-payload solar-electric robotic commercial cargo and resupply
missions in cis-lunar space, to fast human missions to Mars and beyond with
nuclear-electric propulsion (NEP).
The growing importance of NEP missions for which VASIMR® is ideally
suited is reflected in the language of the 2022 Bill submitted by the
Committee on Appropriations for Commerce, Justice, Science and Related
Agencies of the US House of Representatives, which states that
“…at least $10,000,000 shall be utilized to begin a systematic
approach to Nuclear Electric Propulsion…”, and “Within 180 days of
the enactment of this Act, NASA, in coordination with other
relevant Federal departments and agencies such as the Department of
Energy, shall submit a multi-year plan for in-space
propulsion-system demonstration for NEP.”
“It is absolutely inspiring to see how much Franklin Chang Díaz and
the Ad Astra team have been able to accomplish and advance in
the years that I have known them. This technology has major
potential to revolutionize the space industry,” said U.S. Congressman
Brian Babin, Ranking Member of the House Space and Aeronautics
Subcommittee. “Ad Astra’s small but dedicated team is a true testament
of perseverance and continuing to invest in advanced
technologies such as VASIMR® is critical if we want to remain a
country that leads in space exploration,” he added.
The company’s main goal is for the VASIMR® engine to demonstrate thermal
steady-state operation at increasingly higher power levels. This
condition calls for all the temperatures of the engine’s critical
components to be stably maintained by the engine’s thermal
management system.
“The ability to operate continuously at 80 kW is exciting because we
are so close to our 100-kW design goal and needing to focus on
upgrading just a few components,” said Dr. Matthew Giambusso, Ad
Astra Senior Research Scientist, and leader of experiment operations.
“The rapid sequence of successful tests of the last few weeks have
been thrilling,” he added.
Major advances in the design of this system have been achieved in
experimental campaigns lasting days to weeks, each followed by a
period of inspection, disassembly, and improvement. This rapid
prototyping is the basis for Ad Astra’s approach to mature the VASIMR®
technology quickly and provide a competitive high-power electric
propulsion option for both public and private customers.
The thermal management of the VASIMR® engine is uniquely challenging, as
temperatures from millions of degrees in the rocket’s plasma core to
near absolute zero in the superconducting magnet, located a few tens
of centimeters away, must be carefully controlled. This, of course,
in the vacuum environment where the engine must operate. These
stringent requirements have required Ad Astra to develop
innovative manufacturing and assembly techniques to meet unusual
thermal and electromagnetic constraints within the available engine
envelope. “Getting the great diversity of materials to work in harmony
in the environment we subject the engine to has presented major
manufacturing challenges we have had to overcome,” said Mr. Lawrence
“DJ” Dean, Ad Astra’s head of manufacturing.