Louisville CO (SPX) Jun 28, 2021
Sierra Space, the new commercial space subsidiary of global aerospace and national security leader Sierra Nevada Corporation (SNC), will supply the propulsion components and integration services for a Nuclear Thermal Propulsion (NTP) system under a recent contract with General Atomics Electromagnetic Systems (GA-EMS). GA-EMS and Sierra Space will develop and demonstrate an on-orbit NTP system for a Defense Advanced Research Projects Agency (DARPA) program called Demonstration Rocket for Agile Cislunar Operations (DRACO).

While the primary mission of DRACO is to enable fast transit time between Earth and the moon, the development of nuclear powered spacecraft propulsion is also expected to open up deep space exploration to humans.

"This technology is an essential component of the new space economy," said Tom Crabb, vice president of Sierra Space's Propulsion and Environmental Systems group.

"Faster, more fuel efficient propulsion and transportation systems support greater awareness of the cislunar space domain and broader exploration of our solar system. Theoretically we should be able to reach other planets nearly twice as fast with nuclear propulsion, placing less strain on the human body and the environmental systems needed for space travel."

NTP uses a nuclear reactor to heat propellant to extreme temperatures before expelling the hot propellant through a nozzle to produce thrust. Compared to conventional space propulsion technologies, NTP offers a high thrust-to-weight ratio around 10,000 times greater than electric propulsion and two-to-five times greater specific propellant efficiency than chemical propulsion.

"We are really excited about the team dynamic with GA-EMS," said Dr. Marty Chiaverini, director of Propulsion Systems at Sierra Space.

"The GA-EMS reactor is smaller and more technologically advanced and Sierra Space brings extensive experience in developing and fielding mechanical, electrical and thermal conditioning systems that work reliably in space, as well as proven performance with liquid hydrogen-based rocket engines and liquid hydrogen turbomachinery."

The NTP design will utilize a liquid hydrogen propellant heated by a nuclear fission reactor to provide two times the amount of energy than the most advanced liquid propellant rocket engine.

Over the next 18 months, the team will define the system requirements such as power, weight, interfaces and control, and perform some subsystem risk reduction. Follow-on phases are anticipated to complete the demonstration system, leading to a flight test in 2025.