Cameras Improve Navigation for Pilots, Drivers
- Saturday, 01 January 2011
After 10 months of traveling through deep space to Mars, the Phoenix Lander finally approached its destination. The last 7 minutes of the spacecraft’s 423 million-mile-journey—the entry, descent, and landing (EDL) phase—were the most critical and also the most difficult. In the history of Mars landing missions, only 5 of 13 attempts have succeeded. It would have been tragic for Phoenix to go so far yet fail to arrive safely.
Landing on the Red Planet is extremely challenging. Tucked inside its aeroshell, Phoenix entered the atmosphere of Mars at a speed of 12,750 miles per hour. After decelerating using atmospheric drag and a parachute, Phoenix discarded its aeroshell in preparation for touchdown in a region characterized only by orbital reconnaissance data. Lacking real-time terrain mapping and hazard-avoidance capabilities, Phoenix faced the potential for serious damage or tip over from landing on a rock or other surface hazard during the final seconds of the mission.
To ensure the future success and reliability of such crucial landing missions, NASA is investigating a variety of terrain-sensing technologies, including cameras capable of producing real-time, 3D images of planetary terrain under any lighting conditions to reveal hazards and to enable accurate navigation to a safe landing location.
Advanced Scientific Concepts Inc. (ASC), of Santa Barbara, California, received a Small Business Innovation Research (SBIR) award from the Jet Propulsion Laboratory (JPL) in 2006 to assess the suitability of ASC’s 3D flash light detection and ranging (LIDAR) video camera for EDL applications. With the SBIR funding, ASC tested the technology on simulated Martian landscape at the JPL Mars Yard.
“We want the ability to be able to make a real-time map of the hazards as we are landing so we can avoid them. That is what LIDAR is ideally suited for,” says Gary Spiers, supervisor of the Active Optical Sensing Group at JPL.
To develop an integrated landing system capable of detecting and avoiding surface hazards and guiding a crewed or robotic lander to a safe and accurate touchdown, NASA chartered the Automated Landing Hazard Avoidance Technology (ALHAT) Project in 2006. The ALHAT team, combining technical expertise from the Johnson Space Center, Langley Research Center, Draper Laboratory, and JPL, identified flash LIDAR technology as a highly promising approach for real-time terrain mapping and hazard detection. ASC subsequently received several SBIR awards and a NASA Research Announcement contract to continue the development and refinement of 3D flash LIDAR technologies. Over the past few years, several combinations of ASC flash LIDAR sensors and related lasers and optical components have been evaluated by NASA personnel in the lab, in the field, and in airborne tests.
“The primary reason NASA was interested in the technology was for safe landings. The second priority was for rendezvous and docking at the International Space Station,” says Farzin Amzajerdian, a senior scientist at Langley leading the LIDAR sensor development effort for ALHAT.
At Johnson, the Commercial Crew and Cargo Program Office (C3PO) invests resources to stimulate the private sector to develop and demonstrate space transportation capabilities. Under the Commercial Orbital Transportation Services project of this office, Hawthorne, California-based SpaceX is developing its Dragon spacecraft to deliver cargo and supplies to the International Space Station (ISS). Because SpaceX intends to use ASC’s technology to assist with docking at the ISS, the flash LIDAR device flew on both STS-127 and STS-133 for demonstration and evaluation.