July 9, 2013
NASA Developing Laser-Based Deep Space Communications
Brett Smith for redOrbit.com - Your Universe Online
With so many far-flung devices still transmitting data back to Earth, NASA scientists said they are working on a system that could be described as part extraterrestrial GPS, part wireless router.
The Integrated Radio and Optical Communications project, or iROC, at NASA's Glenn Research Center is being designed to improve the speed and efficiency of data transmission back to Earth via a Mars-orbiting relay station.
After receiving data, iROC will use optical lasers to send it on to one of three observatory telescopes around the world. The seemingly simple process is complicated by the need to precisely target a location on the Earth from high above Mars.
"There is no GPS in deep space," said Dan Raible, co-principle investigator of iROC. "So in order to find Earth, you first have to know where you are, and that takes celestial navigation. Just like those sailors from the past knew about the North Star, we will use the same beacons in the sky to guide us."
To perform 21st century celestial navigation, iROC will use two sets of cameras to find two entirely different regions in the sky. Using an algorithm, the iROC then processes the images to give a precise placement within the solar system.
"Just like we need two eyes to give us our depth perception, our system needs two views of the sky to give us precise positional information," Raible said. "Since we know the orbital trajectory of all the planets to a fine resolution, once we know our location, iROC will know where to point the laser beam and it should hit the target back on Earth."
In addition to establishing its position in space, the NASA engineers also need iROC to be able to establish a steady laser beam for transmission - made difficult by the vibrations onboard an orbiting satellite. The iROC engineers said dampening vibrations will be one of their top priorities moving forward.
"If you are trying to keep the ground station in the center of the beam, but vibration is making it dance all over the place, then you are not transmitting data," Raible said.
If iROC scientists are able to solve the problems facing them, they would essentially be able to create a communications network in deep space capable of firing data to Earth-bound scientists in a much faster way, solving their current bandwidth problems.
"We have spacecraft operating out there since the Apollo era and others launched last year like the Mars Curiosity Rover," Raible said. "But they all talk different languages and at different frequencies. Most of them do not talk to each other and beam directly to satellite dishes on Earth."
The iROC engineers also see their system creating inter-operability among all the extraterrestrial NASA assets.Â Such inter-operability would allow Voyager 1 to "talk" to the Curiosity rover and vice-versa. Both assets could also beam signals from a Mars relay station in about 16 hours.
"We want to get some new technology out there that talks to new vehicles as well as some of our heritage hardware," Raible said. "We need to un-constrain the science of deep space missions by fixing the communications bottleneck."