It sounds like something out of a science-fiction book. Putting a high powered laser on ISS, the International Space Station, and pointing it at Earth. However unlike in the books, this laser will be used to research and test deep-space optical communications.
OPALS or Optical Payload for Lasercomm Science is an upcoming research project that will be using the International Space Station as a testbed for new technologies to enable high data transfer rates to and from space via the use of optical laser communications.
Currently spacecraft such as satellites, the robotic rovers on Mars and the ISS all communicate with Earth via radio signals. Very much like how car radios work here on Earth. Using this form of communications has it’s limitations when you want to transfer a large amount of data due to the wave frequency of radio.
The ability to send data back down to mission control is becoming a bottleneck for the science work being undertaken on the ISS. With the dawn of commercial cargo more agencies are able to have work performed on ISS and as the number of experiments running grows the amount of bandwidth needed for both down-linking data and requested high definition video feeds grows too. Currently the ISS is almost bandwidth capped and has a backlog of data that they need to down-link but are unable to process fast enough due to the cap on down-link speeds caused by using radio communications.
“The goal of optical communications technology is to increase the science data future missions can bring back for the same amount of resources,” said Baris Erkmen, OPALS principal investigator at NASA’s Jet Propulsion Laboratory “In low Earth orbit, upcoming Earth science missions are generating more data at rates that are much higher than we are able to bring down now, and our investigation aims to improve NASA’s ability to get more data down for scientists in the future.”
The OPALS project will aim to demonstrate the ability to use optical communications to provide the bandwidth needed to keep up with the amounts of data that NASA deep space missions and ISS are producing currently.
The tests will run over 90 days on ISS involving sending video data from the installation on ISS to the Jet Propulsion Laboratory’s Optical Communications Telescope Laboratory in Wrightwood, California. Each test will last around two minutes, the time that the installation on ISS will be able to maintain line of sight with the ground receiving telescope. During these tests the installation on ISS will transmit pre-encoded video data to the receiving telescope on the ground via its modulated laser beam transmitter.
The installation on ISS will be able to keep itself pointed at the receiving telescope on the ground by the aid of a laser beacon from the ground telescope. The beacon’s laser will be picked up by a camera system on the installation that will allow the installation to track the ground signal and maintain a lock on the ground telescope via use of its closed-loop control system that includes the ability to gimble on two-axis.
The hardware for the project is scheduled to be launched to the ISS in late 2013, project managers are hopeful for an October liftoff of the hardware. Once at ISS, the hardware will be installed on the exterior of the station, being mounted on one of the ExPRESS logistics carriers (ELC) that are installed on the truss sections of the station.
Image Credit: All images from NASA.gov and NASA JPL