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May 18, 2016
Imagine you’re sitting in class watching a scene from “Star Wars” and your professor assigns a project meant to fly in space.
Image above: The three on-orbit SPHERES satellites fly in formation through the International Space Station, appearing like a squadron star fighters from the Star Wars universe. Image Credits: NASA/ISS.
In 1999, that is exactly what happened for engineering students at the Massachusetts Institute of Technology in Cambridge, Massachusetts.
“On the first day of class, I showed the students the clip where Luke Skywalker learns to channel the Force using the free-floating practice droid on the Millennium Falcon spacecraft,” explained David Miller, the professor and creator of the course. “I said that I want three of these droids to fly on the shuttle or International Space Station, except without the lasers blasts," said Miller, now NASA's chief technologist. "And the rest is history.”
Seventeen years later, that class project, called SPHERES -- Synchronized Position Hold, Engage, Reorient, Experimental Satellites -- is celebrating a rare milestone: 10 years of investigation on the International Space Station (ISS).
SPHERES: The Prequel
SPHERES was initially envisioned to be a fleet of space-based satellites to test computer programs for close-formation flying of spacecraft for advanced telescopes, on-orbit satellite servicing and automated docking.
Prior to the first on-orbit test on May 18, 2006, though, Miller realized SPHERES could also host experiments.
Steve Sell, project manager for SPHERES during the early stages of development and operations at Payload Sciences Inc. in Boston, Massachusetts, recalls when Miller approached the small team late in development. “The computer board had a port on it that was available,” Sell said. “Dr. Miller challenged us to figure out a way to get that port out to the outside so we could plug stuff on, and we did.” The project became a research facility for interchangeable experiments onboard the world’s preeminent research laboratory orbiting Earth.
That’s No Satellite! It’s an Experiment Platform!
Image above: Halo -- seen here attached to a blue SPHERES satellite -- is the newest addition to the SPHERES facility. Each Halo attachment is comprised of printed circuit boards, enclosed in 3-D printed plastic, and six expansion ports -- each with power, data connections and computing capabilities. Image Credit: MIT.
These interchangeable add-ons take many forms. A ring-shaped hexagonal structure called SPHERES Halo, resembling a TIE fighter spacecraft in the Star Wars universe, is attached to the satellites enabling them to fly more complicated configurations and host more experiments than before.
Another notable SPHERES-hosted investigation is SPHERES Slosh, a study aimed at understanding the movement of liquid rocket fuels in space.
“Fuels slosh around in the tanks,” said Jose Benavides, program manager for SPHERES at NASA’s Ames Research Center in California’s Silicon Valley. “That slosh adds forces to the direction the rocket is travelling, and if those forces are too big, they’re going to knock the rocket off course, and then bad things happen.”
To simulate the slosh, two SPHERES satellites maneuver a clear container, partially filled with water dyed Yoda-green; a camera and sensors record the liquid’s movement. Researchers incorporate experiment data into computer models, enabling engineers to design safer and more efficient rockets for spaceflight and NASA’s journey to Mars.
Animation above: NASA astronaut Kjell Lindgren and JAXA astronaut Kimiya Yui recorded video of liquids in a small tank as part of the SPHERES Slosh investigation into microgravity fluid dynamics on the International Space Station. Data could help scientists design better fuel systems for future space craft. Animation Credit: NASA.
“For the first time in history, we have validated computer models that allow us to predict the motion of the fluid in the propellant tanks of spacecraft,” Brandon Marsell, principal investigator for SPHERES Slosh. “That’s huge for rocket technology!”
These Are the Droids You’re Looking For…Kind of
In September 2011, the teams added smartphones to the satellites for the project Smart SPHERES, transforming SPHERES into robots capable of performing tasks for astronauts or flight controllers. The tasks are often either too risky or too repetitive and mundane for the crew, freeing the astronauts for activities requiring a human touch.
The project tested ground remote control of the satellites to fly inside the station and provide camera views to the flight controllers as well as testing the robots’ abilities to follow astronauts using facial detection.
VERTIGO Maps Where the Satellites Go
Image above: SPHERES-Slosh test session science 5. Image Credits: NASA Ames.
When robotic missions rendezvous with tumbling asteroids or satellites, they will need an automated way of navigating around the object. SPHERES VERTIGO develops software for vision-based navigation and characterization of tumbling objects using stereo cameras and a computer attached to each satellite. SPHERES then builds 3-D digital models of the object and can navigate around it solely using the model.
An Astronaut’s Question Leads to a Student Competition in Space
When astronaut Greg Chamitoff returned from the space station, he inquired about SPHERES’ software and learned that anyone could program it without violating safety assurance.
With his question “Even high school kids?” Zero Robotics was born.
Image above: NASA astronaut Scott Kelly works with SPHERES on the International Space Station. Image Credits: NASA/ISS.
Student teams worldwide develop computer code for a video game based on a specific NASA challenge, solvable with small, SPHERES-like satellites. Simulations narrow the field and ultimately determine the finalists whose code is tested on the actual SPHERES satellites on ISS, facilitated by on-orbit astronauts.
In its eighth year, the competition proves to be a valuable tool for engaging the next generation of scientists, explorers and engineers while teaching about real-world, off-world challenges.
The SPHERES Legacy
Seventeen years ago in a classroom not that far away, the SPHERES facility was born. As it prepares to hand off its lightsaber of experimentation to the next generation robotic free-flyer, Astrobee, in 2018, team members are looking ahead to the future, while celebrating the successes of nearly 600 test hours over 114 test sessions by 38 on-orbit crew members.
Like SPHERES, Astrobee will be used as a research facility and a remotely-operated robot that can be supervised by mission control for mobile camera work, environment sensing and automated logistics.
Space Station Live: Getting the Buzz on Astrobee
Video Credits: NASA/JSC.
NASA Ames will operate and maintain Astrobee, just as it currently does with SPHERES. Astrobee is funded by the Game Changing Development Program -- part of the NASA’s Space Technology Mission Directorate -- and the Human Exploration and Operations Mission Directorate, both at NASA Headquarters in Washington. Similarly, SPHERES is also funded by the Human Exploration and Operations Mission Directorate.
Perhaps the biggest takeaway from the multi-colored, bowling ball-sized SPHERES satellites is not in the data returned or the similarities to Astrobee but in the classroom where it all began. “Just because something is a student project doesn’t mean it’s only academic,” said Sell. “You can take a student project and turn it into something really great. That’s just a wonderful thing.”
SPHERES Halo: http://www.nasa.gov/spheres/halo-1
SPHERES Slosh: http://www.nasa.gov/content/slosh-experiment-0
Smart SPHERES: http://www.nasa.gov/mission_pages/station/main/spheres_smartphone.html
SPHERES VERTIGO: http://www.nasa.gov/content/vertigo-visual-estimation-and-relative-tracking-for-inspection-of-generic-objects-0
Zero Robotics: http://zerorobotics.mit.edu/
NASA’s journey to Mars: http://www.nasa.gov/topics/journeytomars/index.html
NASA’s Ames Research Center: http://www.nasa.gov/centers/ames/home/index.html
Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html
International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html
Images (mentioned), Video (mentioned), Text, Credits: NASA/William Bryan.