Jul 22, 2001

Building a 'Droid for the International Space Station


 Building a Droid for the International Space Station


Inspired by science fiction classics, NASA scientists are building a talking, thinking and flying robot to help astronauts with their chores in space.




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July 23, 2001 -- It looks like something straight out of a Star Wars movie. And to hear it described -- a self-propelled, floating, talking, computerized personal assistant with artificial intelligence -- you might suspect it really is a "droid" from a science fiction film.


The similarity isn't a coincidence. The design was actually inspired by the small floating sphere that Luke Skywalker sparred against in the original Star Wars!

The idea may have its roots in science fiction, but this droid is quickly becoming a reality at NASA's Ames Research Center.

Soon these little robots, called "Personal Satellite Assistants" (or PSAs for short), may be flying on board the space shuttle and living in the International Space Station (ISS). They will help the crew save valuable time by assisting with routine chores. And they could be lifesavers when emergencies arise.

Above: It may look like something out of science fiction, but this softball-sized robot helper could soon be aiding real-life astronauts with their daily tasks. Pictured is Yuri Gawdiak, principal investigator for the project at the NASA Ames Research Center.




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"I looked a little bit at the lightsabre training remote in Star Wars. That was part of the inspiration for [the PSA]," says Yuri Gawdiak, who originated the PSA concept and is now the project's principal investigator.

Another science fiction classic -- Star Trek -- gave some of the astronauts an idea for a tool that would be useful on missions.

"The astronauts requested a 'tricorder'-like capability," Gawdiak says, referring to the portable device that landing parties on Star Trek would use to survey the atmospheres of alien planets. 

"We took it a step further and said we can give you a 'tricorder' and a personal digital assistant ... and make it autonomous," Gawdiak says.


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Left: This 15.2 cm (6 in.) robot will fly autonomously around the shuttle or space station, floating effortlessly in orbital free fall and propelling itself with 6 small ducted fans. Click on the image for a showing the various parts of the PSA.

Like the fictional tricorder, the PSA will have sensors that can detect the pressure and temperature of the ambient air, as well as concentrations of gases such as CO2. For astronauts living in a sealed aluminum can in the vacuum of space, this kind of information can be a matter of life and death.

"It's kind of like having a canary on your shoulder," says former PSA systems designer John Loch. Miners used to keep a caged canary down in mine shafts to act as an early-warning device for subterranean methane that sometimes asphyxiated miners.

"If the canary starts getting dizzy, you'd better start heading for your spacesuits," Loch says.

PSAs can also venture into situations that might be too dangerous or uncertain for their human crewmates. "[Astronauts] might seal off one of the modules if there's a suspected problem, and then have the PSA check it out before humans go in," Loch says.


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Right: Click on the image for a 1.1 MB QuickTime animation of the PSA in action.


But crew members won't need to wait for an emergency to make use of their PSAs. The little softball-sized robots can help out with many day-to-day tasks as well.

"For example, if a crew member is taking something apart, the PSA could be floating over their shoulder and helping by telling them, 'Okay, remove this cover, take this latch off, move this wire over here, and so on,'" Loch says. "A floating, talking clipboard would be a good way to describe it."

A small LCD display on the ball can also display simple lists and status information. The PSA would have a wireless network connection to the computers of the shuttle or space station, enabling it to access information about hardware, inventory, crew schedules, or science experiments -- then relay that information to crew members as needed.

And if crew members have a question, they can simply ask. The PSA will have advanced voice-recognition and intent-interpretation technologies that will allow it to understand spoken questions and commands.


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Such cutting-edge "intelligent" technology is a major area of on-going research at Ames. This artificial intelligence also allows the PSA to plan autonomously its own motions and actions -- saving the crew from having to "baby sit" it.

Left: The PSAs sensors will allow crew members and ground controllers to sample the atmosphere anywhere inside the station. Click on the image for a



The hope is that the PSA will save time for the crew members, because, as Loch puts it, "The most valuable resource on the station is the astronauts' time." 

These little robots will also add some unique capabilities to the ISS.

For example, the on-board video camera and microphone could allow a scientist on the ground to have a "virtual presence" on the space station, overlooking as a crew member works on the scientist's experiment. The scientist could watch in real time and give the astronaut instructions and advice.

And mission controllers on the ground could recruit a PSA and ask it to look around the station, check on experiments, or investigate possible air leaks.


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Right: By flying in a parabolic arc, airplanes can simulate weightlessness here on Earth! A prototype of the PSA will be tested in a weightless (freely-falling) environment aboard a NASA KC-135 next year.

Ames researchers are using off-the-shelf parts to help keep costs down. The robot's computer is a Pentium® III running Linux, and the six ducted fans it uses for propulsion are commercial products made for model airplanes. Even the infrared distance sensors it uses to avoid collisions are pre-made sensors similar to those in auto-flush toilets!

Prototypes have already been made, and next year the PSA team plans to fly one on a KC-135 airplane. The plane, which is used in astronaut training, creates an artificial weightless environment by flying parabolic arcs in the sky.

If all goes well, the crews of the shuttle and the ISS may soon have a new high-tech helper -- proving once again that yesterday's science fiction is tomorrow's science fact!



Editor's Note: The word droid is a contraction of android, which means a mobile robot in human form. Unlike androids, however, robotic droids can take any form -- including red softball-sized spheres.




Building a 'Droid for
the ISS
July 23, 2001

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 Thursday's Classroom

KID'S STORIES: 3rd and 4th grade -- 5th to 8th grade -- 9th grade and older
  • Discussion Questions: These discussion questions are crafted for 3rd to 8th graders, but they will work in many high school classes, too. [lesson plan][activity sheet]
  • Do-it-yourself Droids: Make your own papier-maché droid and decorate it with all the gizmos you think a good robot helper should have. [lesson plan]
  • Touché, Droid!: The inspiration for ball-shaped PSAs was Luke Skywalker's robotc sparring partner in Star Wars. Kids can color this picture of an astronaut brandishing a light sabre and fencing with an elusive 'droid -- science or science fiction? [Touché Droid]


Use this button to download the story with lessons and activities in printer-friendly Adobe PDF format:
Web Links


Personal Satellite Assistant -- project home page, from NASA's Ames Research Center

NASA Ames Research Center -- home page

Science Fiction to Science Fact -- learn more about ideas from science fiction that have become real

International Space Station -- home page for the orbiting laboratory currently being constructed by a cooperative consortium of the world's nations

The philosophical underpinings of artificial intelligence -- a short introduction to artificial intelligence by ARC's Silvano Colombano, in PDF format

Artificial intelligence subject guide -- references to books, articles, and web resources related to the subject of artificial intelligence


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