Spaceflight Insider

Aerojet Rocketdyne’s $67M contract with NASA set to develop new SEP system

A prototype 13-kilowatt Hall thruster

Engineers in the Solar Electric Propulsion (SEP) project tested this prototype of a 13-kilowatt Hall thruster at NASA’s Glenn Research Center in Cleveland, Ohio. The testing demonstrated the prototype’s readiness for industry to develop this new high-powered solar electric propulsion into a flight-qualified system. (Click to enlarge) Photo Credit: NASA

NASA announced last week their selection of Aerojet Rocketdyne, Inc., of Redmond, Washington, to develop a newly advanced electric propulsion system. The new system is the next step in NASA’s Solar Electric Propulsion (SEP) project, which is developing new technologies to expand the range and capabilities of future science and exploration missions.

“Through this contract, NASA will be developing advanced electric propulsion elements for initial spaceflight applications, which will pave the way for an advanced solar electric propulsion demonstration mission by the end of the decade,” said Steve Jurczyk, associate administrator of NASA’s Space Technology Mission Directorate (STMD) in Washington via a press release. “Development of this technology will advance our future in-space transportation capability for a variety of NASA deep space human and robotic exploration missions, as well as private commercial space missions.”

Engineers in the SEP project at NASA’s Glenn Research Center in Cleveland, Ohio, have developed a prototype 13-kilowatt Hall thruster. Exhaustive testing on the prototype at NASA Glenn have demonstrated the design’s technology readiness for further development by industry. The new contract directs Aerojet Rocketdyne to oversee the development and delivery of an integrated electric propulsion system consisting of a thruster, power processing unit (PPU), low-pressure xenon flow controller, and electrical harness.

“What this technology moves us to in this device is a capability over two times greater than what is presently being flown today,” Bryan Smith, director of the Space Flight Systems Directorate (SFSD) at NASA Glenn said in a teleconference last week. “When we take strings of these engines together, we move to a level of 50 kW of electric propulsion capability, and with that, you can do significant orbital transfer operations. That’s where we really begin to see the moving of assets into deep space, and it becomes that next step in deep space exploration that we’ve been trying to do.”

A prototype 13-kilowatt Hall thruster

Shown here is a 13-kilowatt Hall thruster being evaluated at NASA’s Glenn Research Center in Cleveland. (Click to enlarge) Photo Credit: NASA

The contract is a 36-month cost-plus-fixed-fee contract with a performance incentive and total value of $67 million. Development of the new design could potentially increase spacecraft fuel efficiency by 10 times over current chemical propulsion technology. The new design would also more than double the thrust capability of current 4.5 kW electric propulsion systems.

This work progresses in tandem with recent work in advanced solar array systems, also funded by STMD. The newly advanced solar array systems are expected to generate the electrical power to operate the new electric propulsion flight system.

Aerojet Rocketdyne, working with the engineering team at NASA Glenn, will build, test, and deliver development units for further evaluation and testing. If development proceeds successfully, NASA will exercise the option period of the contract, and the development units will further inform the design, construction, and delivery of the eventual flight units. Aerojet Rocketdyne will then verify and deliver four integrated flight units, which at this time are expected to serve as the propulsion units for NASA’s Asteroid Redirect Robotic Mission (ARRM) – a mission to fly to an asteroid, pluck a large boulder from its surface, and return it to a lunar orbit, where astronauts aboard the Orion spacecraft will fly to investigate the boulder.

“This is an evolution of the previous electric propulsion technology,” Jurczyk said. NASA Glenn has been a leader in developing spaceflight electric propulsion technology for over fifty years. The most recent example of the technology’s success in deep space is the Dawn mission, which surveyed the giant asteroid Vesta and the dwarf planet Ceres between 2011 and 2015.

“The way we’ve tried to do this is to not jump off and build a giant thruster right away,” Smith said. “Then you’re stuck with something that might be oversized. We’re trying to pick the right sized thruster to allow us to do a significant enhancement of what we do today (today’s operational level is 4.5 kW). So we moved significantly to 12.5 kW. It’s an achievable level that we can do. Sometimes you may want to use just a single engine for a particular mission. So this allowed a building block approach. It also fit in with what we believed was our next increment, and the ARRM mission is an example of it – a 50 kW mission. So we basically designed it in that building block fashion.”

The development of more powerful solar electric propulsion is viewed by NASA as an important component of getting humans to Mars. Manned spacecraft bound for Mars may not be powered by solar electric propulsion, although a combination of chemical propulsion and solar electric propulsion is possible. However, the many spacecraft carrying equipment, habitats, and other support materials in advance of a human landing on Mars can make the long transit in a much more cost-efficient way with the use of solar electric propulsion.

“One way to look at this is that it is like a new drivetrain,” Smith said. “If you look at the high power arrays that the STMD has developed, and you couple that with what I call this new engine system, we are basically developing a whole new drivetrain for deep space exploration.”


Michael Cole is a life-long space flight enthusiast and author of some 36 educational books on space flight and astronomy for Enslow Publishers. He lives in Findlay, Ohio, not far from Neil Armstrong’s birthplace of Wapakoneta. His interest in space, and his background in journalism and public relations suit him for his focus on research and development activities at NASA Glenn Research Center, and its Plum Brook Station testing facility, both in northeastern Ohio. Cole reached out to SpaceFlight Insider and asked to join SFI as the first member of the organization’s “Team Glenn.”

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