Northrop Grumman Developing Solar Electric Propulsion Under NASA Contract

REDONDO BEACH, Calif., Jan. 31, 2012 (NGC PR) — Northrop Grumman Corporation was recently awarded a contract to study high-power solar electric propulsion flight system technology for NASA deep space and human exploration missions.

“In collaboration with our partners, we are working on alternatives to the typical solar array approach,” said Jim Munger, solar electric propulsion program manager, Northrop Grumman Aerospace Systems. “Our concept will be scalable to 300 kilowatts and beyond and have the potential for reducing the cost and complexity of high-power requirements.”

The company is partnered with Sandia National Laboratories and the University of Michigan’s Department of Aerospace Engineering to create a technology road map for near-term NASA space missions.

NASA’s goal is to develop a high-power solar electric propulsion system for a “space tugboat” that can ferry satellites from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO), saving fuel and secondary booster costs. The availability of a solar-powered vehicle would make it possible to launch spacecraft to LEO, then ferry them to GEO, allowing much heavier payloads to reach GEO while still using existing launch vehicles.

The study is designed to develop mission concepts that will be using technology at NASA Technology Readiness Level (TRL) 5 or greater, which means that a basic prototype has been validated in a relevant environment (simulating space) and includes initial integration at some level with other operational systems.

Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation for the U.S. Department of Energy’s National Nuclear Security Administration. With facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major research and development responsibilities in national security, energy and environmental technologies, and economic competitiveness.

The Department of Aerospace Engineering at the University of Michigan, Ann Arbor, Mich., has been recognized as one of the leading departments of its kind in the country. Professor Alec D. Gallimore will lead the department’s effort for Northrop Grumman.

NASA Glenn Research Center, Cleveland, Ohio, will manage the project. In addition to other numerous technology development activities, the Center designs game-changing technology for spaceflight that enables further exploration of the universe.

Northrop Grumman is a leading global security company providing innovative systems, products and solutions in aerospace, electronics, information systems, and technical services to government and commercial customers worldwide. Please visit for more information.

  • Michael Turner

    “NASA’s goal is to develop a high-power solar electric propulsion system for a “space tugboat” that can ferry satellites from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO), saving fuel and secondary booster costs.”

    And, notwithstanding the space-cadet shibboleth that LEO is halfway to anywhere in the solar system, reaching GEO can cost as much as three times what it costs to get to LEO. So this tugboat, combined with a possible 4x LEO cost reduction from SpaceX, would be significant.

    With enough oomph, it might also help with changing orbital planes near Earth. I’ve long wondered whether, logistically, it would make sense to just launch *everything* into equatorial LEO. One might then use electric-propulsion tugs (with ion drives, and maybe electrodynamic tethers for the initial climb to a Hohman transfer apogee) to put the payload into the target trajectory — whether that’s GEO, polar orbit, or whatever.

    As well, any serious permanent moonbase plan probably requires a lunar cycler-based logistics chain. Shielding passengers and CELSS systems against solar storms on the way to and from the moon will require enormous shielding mass. You’ll want a very efficient engine even if the delta V is only a few meters/second for each cycle.

    And a lunar cycler ferrying people with a CELSS system might be thought of as prototyping a Mars cycler for human transit to a Martian moon.

    In short, getting a 300kW ion drive up to TRL 5 could yield the path of least resistance to everything else, be it commercial, scientific and expeditionary. So I like this move very much, and I hope it works out. Out with the hare, in with the tortoise!

  • dr

    This is great news.
    One of the problems that we face in exploring our solar system is simply the size. So we need to travel fast in order to make the journey times reasonable. However, we don’t really want to have to exceed the exhaust velocity on our vehicle because that then starts to need large fuel requirements. Hence high exhaust velocities become desirable. Electric thrusters can have exhaust velocities way beyond chemical rockets, so development in this area is important for the future.
    I also note that a “tugboat” is potentially extremely useful.
    It can be used for collecting satellites in GEO and moving them down to the ISS for servicing, before pushing them back up. Alternatively, you could take the service crew or robot from LEO to GEO to do the service, then return them to LEO.
    Also, I think that I am right in saying that the delta-v from LEO to GEO is about 3km/s whereas from LEO to low lunar orbit is about 4.5km/s.
    Hence it is hard to conceptually imagine a tugboat that can be used to shuffle materiel between LEO and GEO that can’t also be used to take materiel from LEO to low lunar orbit.
    If you want to take humans beyond LEO, then my understanding is that it is a good idea to avoid the inner Van Allen belt. In order to do this, you need to be able to add enough delta-v in half an orbit to make one orbit just below the belt and the next just above it (or have huge heavy rad shielding on your spacecraft, which may not be desirable). This creates a minimum thrust requirement based on the total size of your vehicle.
    What is really nice about this, is that it can be expected that this architecture should be quite scalable, so should allow the same sorts of technology to be developed from a small tugboat operating between LEO and GEO through to visiting the moon again and then on to NEOs and Phobos and Deimos.
    Obviously the development will take a long time.
    The other thing is that for example when Apollo was performed almost all the rocket was disposable and whilst the command modules returned to earth, I don’t believe that they were reused.
    This technology should mean that any “tugboat” that is constructed will be reusable at least a few times, and this should mean that the costs of going beyond LEO become more similar to the costs of going to LEO, due to the fact that you can ameliorate your capital costs over multiple missions.
    Obviously shifting from chemical propulsion to electric propulsion and from LEO to GEO or Low lunar orbit and moving from disposable to reusable creates a cultural shock within organisations using this technology so adoption may take time.