August 20, 2012
Credit: Credit: NASA Jet Propulsion Laboratory
Even as more senior staffers at the Jet Propulsion Laboratory in Pasadena, Calif., begin to explore Mars with the state-of-the-art Curiosity rover, a group of scientists, engineers and neophyte managers in their 20s is preparing to use whatever is at hand to validate space-to-ground laser communications. That includes commercial-off-the-shelf (COTS) avionics, the International Space Station and the SpaceX Dragon cargo carrier.
The results—delivered under a program at JPL to give young staffers full responsibility for serious space projects as a way to prepare them for future cutting-edge work—will help validate a faster way to retrieve data from robotic and human spacecraft. As high-resolution imagery from Mars trickles down at an agonizing rate via UHF links, the Optical Payload for Lasercomm Science (Opals) project is working on laser communications from space to broaden the bandwidth.
Working in the same clean room where Curiosity was assembled, the “young-hires” of Opals are preparing their testbed for flight to the ISS. The project manager, a physicist who cut her teeth on a cubesat as an undergraduate, hopes to obtain her doctorate in astrophysics and apply her skills building instruments or spacecraft to explore that discipline. The station systems lead was an entrepreneur in college, and may go back in that direction later on. The project systems engineer is immersed in the kind of detailed work some engineers do not get to do until they are in their 40s. No one in Opals has hit 30 yet.
“Everybody that's working on Opals in a position of responsibility . . . when they started, they were less than three years out of college,” says Bogdan Oaida, the 28-year-old systems engineer.
JPL management set up the Phaeton program to ensure the lab has a steady supply of experience for its cutting-edge projects. Mentors guide the young-hires, who must apply and be chosen for the selective program. But the final decisions are left to them.
The Opals project has produced an experiment that will beam data down from the ISS to a telescope in Wrightwood, Calif. The principal goal is to develop the software needed to aim the laser with enough accuracy to transmit a 10-sec. test video, using the laser beam to carry the digital signal. The data rate—30-50 mbps—is “quite modest,” says Oaida. “What we're really interested in demonstrating is our ability to point and track.”
To do the job, while holding the cost to “less than $20 million,” in the carefully chosen words of Project Manager Parker Fagrelius, the Opals team has used a COTS laser and avionics boards, plus a custom power board, that are kept in a sealed aluminum canister pressurized to one atmosphere to avoid the need for space-rated hardware. Outside the canister is a two-axis gimbal, and an optical head with an uplink camera and a laser collimator for the downlink. The uplink camera used a lot of sophisticated software to home in on a laser target beamed up from Wrightwood, and the laser in the canister beams the test video back down via a fiber-optic cable and the collimator to a 1-meter telescope receiver there. “We are the first space terminal that JPL will build,” says Fagrelius. “There have been experiments between the ground and flight, and a lot of research and work has been done here to make the next step from Opals possible, into deep space and from Mars. But putting something into space, this will be the first step for JPL.”
To get to space, the Opals team will put its 500-lb. payload—which includes the weight of its standard ISS Flight Releasable Attachment Mechanism (FRAM) mounting plate—in the unpressurized “trunk” of the third station-resupply mission on a SpaceX Dragon, now scheduled for next summer. The testbed will be attached to a nadir-side Express Logistics Carrier (ELC) on the ISS with the station robotic arm (see illustration). In the three years since the project started, engineer Robert Witoff has been in charge of working with NASA's ISS office at Johnson Space Center to arrange the station deployment.