13 Mar 2014
'OPALS' system - launching on 16 March - will enable 50Mbit/s, later 1Gbit/s, transmissions from Earth orbit.Jet Propulsion Laboratory (JPL), Pasadena, Ca, USA, have developed a new method of transmitting video and large volumes of data from the International Space Station back to Earth.
A team of 20 researchers working on the lab’s Phaeton program, have developed the Optical Payload for Lasercomm Science (OPALS) investigation, which is being prepared for a March 16 launch to the International Space Station aboard the SpaceX-3 mission. Their goal is to achieve NASA’s first optical communication experiment on the orbital laboratory.
Scientific instruments used in space missions increasingly require higher communication rates to transmit data back to Earth or to support high-data-rate applications, such as high-definition video streams.
"Optical communications has the potential to be a game-changer," said mission manager Matt Abrahamson. "Right now, many of our deep space missions communicate at 200 to 400 kilobits per second.” OPALS will initially demonstrate up to 50 Mbit/s and future deep space optical communication systems will provide over 1 Gbit/s from Mars, he added.
"It will be like upgrading from dial-up to DSL," added project systems engineer Bogdan Oaida. "Our ability to generate data has greatly outpaced our ability to downlink it. Imagine trying to download a movie at home over dial-up. It’s essentially the same problem in space, whether we’re talking about low-Earth orbit or deep space."
After the Dragon capsule docks with the station, OPALS will be robotically extracted from the trunk of the Dragon, and then manipulated by a robotic arm for positioning on the station’s exterior. It is the first investigation developed at JPL to launch on SpaceX's Falcon rocket.
As the space station orbits Earth, a ground telescope tracks it and transmits a laser beacon to the OPALS. While maintaining lock on the uplink beacon, the orbiting instrument’s flight system will downlink a modulated laser beam with a formatted video. Each demonstration, or test, will last approximately 100 seconds as the station instrument and ground telescope maintain line of sight.
It will be used to study pointing, acquisition and tracking of the very tightly focused laser beams, taking into account the movement of the space station, and to study the characteristics of optical links through Earth’s atmosphere. NASA will also use OPALS to educate and train personnel in the operation of optical communication systems.
OPALS is a partnership between NASA’s Jet Propulsion Laboratory in Pasadena, Calif.; the International Space Station Program based at Johnson Space Center in Houston; Kennedy Space Center in Florida; Marshall Space Flight Center in Huntsville, Ala., and the Advanced Exploration Systems Division at NASA Headquarters in Washington.
About the Author
Matthew Peach is a contributing editor to optics.org.