Deep Space Industries and the University of Tennessee have been awarded NASA Innovative Advanced Concepts (NIAC) program funding for developing technology to slow spacecraft carrying asteroid resources as they return to Earth’s orbit.
The purpose of asteroid mining is to collect fuel and building materials harvested from near Earth asteroids and provide them to commercial and government missions. One major challenge to making asteroid mining a reality is slowing down the returning mining spacecraft as they approach Earth. Returning from distant destinations, these spacecraft will be traveling at high speeds, so slowing them down enough to slip into orbit is quite difficult.
Current braking methods call for the returning asteroid mining spacecraft to expend a great deal of propellant to slow itself down enough to achieve low Earth orbit insertion. However, propellant is heavy and valuable, so if another way of slowing the spacecraft could be devised, it would significantly help the economics of asteroid mining missions.
The NASA grant will research the manufacturing of an aerobrake system from the asteroid’s regolith (soil) collected from mining operations. The idea is that the fully laden asteroid mining spacecraft will use the collected material to manufacture a braking system during its journey back to Earth’s orbit. The aerobrake system would act as a large heat shield that would allow the spacecraft to pass through Earth’s atmosphere, creating enough drag to slow down the payload without using propellant.
“Using aerobrakes instead of propellant will expand by 30 to 100 times the number of asteroids where water and other supplies can be affordably delivered to markets in Earth orbit,” said Dr. John S. Lewis, chief scientist at DSI. “In the near future,” explains Lewis, “asteroid resources will support space stations, expeditions to the Moon and Mars, and the transfer of payloads from low orbit to geosynchronous orbit by space-based tugs refueled with asteroid propellant.”
The NASA Phase 1 NIAC grant utilizes asteroid simulants produced at DSI’s Space Coast asteroid mining research facility in Orlando, Florida. A key technology for fabricating an aerobrake system from asteroid regolith is microwave sintering, a process that fuses dirt particles together through heat and compression. A portion of the grant will fund Dr. Thomas Meek of the University of Tennessee at Knoxville, who will build on his earlier work sintering lunar regolith.