Hold Steady: Draper Jetpack Technology Could Make it Easier to Explore Asteroids, Mars

CAMBRIDGE, MA– NASA’s vision for manned space exploration begins with sending humans to visit an asteroid, where simple tasks like swinging a hammer or digging with a shovel could cause a person to float away due to the microgravity environment. While astronauts have an emergency self-rescue device that can help them return to the International Space Station should they become detached, the thruster-equipped hardware is not designed for precision extra-vehicular activity (EVA) tasks where a stable work platform is required. Many of the basic movements involved with exploration become limited when thrusters are firing while astronauts are performing these tasks.

Draper is addressing this challenge with a new jetpack approach that combines thrusters with control moment gyroscopes (CMGs) that can help keep astronauts stable as they work in microgravity. The company recently began demonstrating the CMG hardware in microgravity in collaboration with the Massachusetts Institute of Technology (MIT) aboard parabolic flights on a NASA DC-9.

This hardware flight demonstration in microgravity builds on earlier simulation demonstrations conducted in the NASA Johnson Space Center (JSC) Virtual Reality Lab (VR Lab). A few scenarios were simulated using the system, including maneuvering and handling tools on an asteroid surface and on the ISS.

“When astronauts are not stable, their ability to perform basic tasks critical for exploring an asteroid or other low-gravity object is threatened,” said Michele Carpenter, Draper’s principal investigator for the jetpack project. “Thrusters can keep them from floating away, but they don’t offer the level of control needed to hold astronauts steady during precision tasks.”

During the flight demonstration, the CMGs were mounted on free-floating Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) platforms. The CMGs were used to perform attitude hold, slew and pointing maneuvers. In addition, the CMGs were able to reject disturbance torques imparted by the thrusters of a docked secondary satellite.

NASA previously used the Manned Maneuvering Unit (MMU) on three missions in 1984 to allow astronauts to conduct untethered EVAs. Jeffrey Hoffman, the MIT professor who participated in the SPHERES experimentation during the recent parabolic flight, said that NASA had conducted tests in the early 1970s inside the Skylab space station with a version of the MMU featuring CMGs that were intended to increase stability and reduce thruster propellant use. However, NASA deemed the CMGs available in the 1970s too heavy and power-hungry for use with the operational MMU.

“Current technology has produced CMGs that are much lighter and use less power, renewing interest in using them for maneuvering system flight operations,” said Hoffman, a former astronaut who flew on five space shuttle missions. “If we are serious about someday exploring the satellites of Mars and other low-gravity objects, then we need to give astronauts the freedom to move around outside their spacecraft. This is the goal of the Draper-MIT experiments.”

In addition to space exploration missions, potential applications of this technology could range from stabilizing divers and unmanned underwater vehicles, to stabilizing hands during surgical procedures and other high-risk tasks where precision is required.

The project leverages Draper’s expertise in human systems engineering, as the company worked with astronauts to understand the movements that will be involved with surface exploration and modeled those tasks in a system simulation. This simulation, which included a NASA graphics package for data visualization, was then integrated with JSC’s VR Lab environment so that users could pilot the system in real time. Draper also drew upon its expertise in using CMG actuation for stabilizing Earth imaging satellites to address the jetpack attitude stabilization challenge.