ISS astronauts control robot on Earth via "interplanetary internet"
By David Szondy
November 14, 2012
The internet has changed a great deal of modern society, and now it promises to change space exploration as well. In late October, International Space Station (ISS) Expedition 33 commander Sunita Williams used a NASA-developed laptop aboard the station to control a LEGO Mindstorm robot, located at the European Space Agency (ESA) European Space Operations Centre in Darmstadt, Germany. Using a “space internet,” she was able to control the robot in real time despite being in orbit at an altitude of 230 miles (370 km).
Manned missions to explore the Solar System haven’t progressed very far since the days of the Apollo program because sending astronauts into space is difficult, expensive and extremely dangerous. This is especially true for landings, where the failure of a single system can result in death on an alien world. Robot probes are cheaper and safer, but limited in what they can accomplish.
One idea that NASA and ESA are looking at involves sending astronauts on missions to orbit planets like Mars or Venus, and then sending down robots that can be controlled remotely. Avoiding landings saves a great deal of money and avoids a lot of hazards, but by having astronauts in orbit they can control robots much more easily than mission control could from hundreds of millions of miles away.
The purpose of the ESA-led experiment was to simulate orbital telepresence. It involved a robot made out of LEGO bricks called Mocup, which stands for Meteron Operations and Communications Prototype. Meteron is itself an acronym that means Multi-purpose End-To-End Robotic Operations Network. This is an ESA initiative for future missions to the Moon, Mars and other bodies in the Solar System. Mocup was set up on a mock planetary landscape where it sent back images to the ISS to help Williams guide it. The test was a simple one, with the robot commanded to move forward and take pictures.
However, it isn’t controlling the robot that’s important. It’s how it was controlled. Communications between orbit and ground is not always stable – ask anyone who has satellite internet. This is even worse when exploring planets like Mars, where shifting orbital positions, weather and other conditions can cause all manner of communications problems.
NASA’s solution was to use something like the internet to do the job, with its Disruption Tolerant Networking (DTN) protocol. This uses a Bundle Protocol (BP) which is similar to Internet Protocol (IP) except that, unlike IP, it doesn't assume a secure connection, but rather that the link will break periodically due to less than ideal conditions. Data bundles are temporarily stored when the connection is broken and then sent once it’s restored. It’s a form of “space internet” that would allow astronauts to control robots in real time with less chance of that all-too familiar internet phenomenon of a failed download.
Now that the ISS tests have been completed, the NASA laptop will be returned to Earth for assessment by ESA.