During a routine spacewalk, astronauts can easily lose their sense of orientation and direction. Creators of a new kind of spacesuit aim to address the challenge — with the push of a button.
In collaboration with NASA, researchers from the Cambridge, MA-based nonprofit Draper are developing a backup capability — a “Return to Home” activator — that secures an automatic, efficient, and safe trip back to the space station.
A Spacewalk Gone Wrong
Zero-gravity conditions present disorienting, sometimes dangerous, challenges for astronauts conducting the “extravehicular activity” known as a spacewalk.
In 2013, a European Space Agency astronaut’s suit and helmet began to fill with water, requiring crewmates’ assistance to bring him back to the airlock.
Draper’s proposed technology supports a safe homecoming for space-station astronauts in the event of an emergency. The “extravehicular activity self-return” combines a sensor, navigation module, guidance algorithms, and controls.
Kevin Duda, a space systems principal engineer at Draper, recently filed the patent for the self-return system. The lead inventor heads the Human Systems Integration Group, a team responsible for architecting technologies where the human — a soldier, a pilot, an astronaut — is the central element of a complex technology.
“The ‘Take Me Home’ system computes a trajectory that will automatically fly you safely and efficiently back to the airlock so that your crewmembers can assist you,” Duda told Tech Briefs.
The Need for a New Suit
In addition to today’s spacesuit, also known as the Extravehicular Mobility Unit (EMU), a spacewalking astronaut currently wears the SAFER (Simplified Aid for EVA Rescue) system.
Strapped on like a backpack, the self-contained SAFER unit’s nitrogen jet thrusters allow astronauts to maneuver in space. Through hand controllers, an astronaut controls orientation and translation around the International Space Station (ISS).
In terms of its jet pack operation, however, Draper’s team lead considers the current spacesuit to be somewhat manual.
“There’s no navigation system on the spacesuit, so it doesn’t know where it is in relation to any of its surroundings,” said Duda.
The lone sensor on the EMU and jet pack: a rate gyroscope, which detects direction to prevent an astronaut from tumbling.
Draper’s self-return system design keeps the thrusters but adds a navigation capability — one that uses GPS, vision-aided navigation, or a star-tracker system to determine a precise location in space.
Knowing where you are is only part of the answer, of course. You also need to know where you’re going.
Draper’s guidance algorithms compute several optimal trajectories, much like a GPS system, to find the most efficient route, accounting for parameters like orbital mechanics, safety requirements, oxygen consumption, and proximity to sensitive space-station structures such as solar arrays.
In addition to the guidance software that provides a path for the wayward astronaut, other algorithms determine how to fire the thrusters in order to stay on the particular route.
Control Moment Gyroscopes (CMGs) offer attitude or orientation control, and thrusters provide translation or linear movements.
The system’s sensors and helmet visor display also send the astronaut directions through a combination of visual, auditory and sensory cues.
The “Take Me Home” button could be physically located on suit itself, said Duda, or could be actuated by someone remotely inside the space station or on the ground. Biosensors in the suit could theoretically determine when an astronaut is unresponsive and activate a return automatically.
From Space to Earth
Knowing where you are and where you need to go is not fundamentally just a space challenge.
Duda says the technology could be also used on Earth: to guide scuba divers through dark environments or send firefighters through burning buildings, for example.
“The most exciting thing is the ability to integrate all of these complicated systems into one working device that has a broad applicability to both astronauts and those on Earth,” said Duda.
Although no timeline exists currently for adoption of the new spacesuit idea, Draper has done some early prototyping with NASA to refine the design and test the automatic return capabilities.
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