LiDAR VNS System Should Make Docking Spacecraft At ISS Easier

For the past two years, NASA engineers and contractors have worked together to develop a technology that would make it easier for future space vehicles to dock to the International Space Station. Their solution, the Vision Navigation Sensor (VNS) will be tested on the STS-134 mission scheduled for July.

Developed by the Orion Project Office at NASA's Johnson Space Center in Houston, the VNS, as well as a docking camera, have the ability to advance the capability necessary for automated rendezvous and docking. The system is a part of the Sensor Test for Orion Relative Navigation Risk Mitigation (STORRM) Development Test Objective.

"The VNS is the most advanced relative navigation sensor that has been developed for spaceflight in support of rendezvous and docking," said Howard Hu, manager of Orion vehicle system performance and analysis at Johnson. "The Orion Project is excited to help NASA advance this technology and looks forward to validating its performance using the space shuttle and the ISS environment."

The first element of that technology - five retro-reflectors designed by NASA Langley Research Center in Hampton, VA. - will launch on space shuttle mission STS-131 Monday, April 5. The retro-reflectors - which are made from reflective material similar to that on stop signs - are specialized reflectors that reflect light back with a minimum scattering of light. They will serve as the targets for the VNS.

STORRM Sensor Photo Courtesy NASA

The VNS is an eye-safe flash light detection and ranging, or LiDAR, system that provides an image of the target, in this case the space station - along with range and bearing data to precise accuracies. The docking camera is designed to provide high resolution, color images. "The new vision navigation system that is being tested would make it easier for the astronauts during docking operations and give them more information earlier on about where they are in proximity to the ISS, on the order of centimeters," said Audra Bullock, the reflective elements lead at NASA Langley.

"The sensor provides two to three times more range capability than any other space LiDAR system today," added Heather Hinkel, the STORRM principal investigator at Johnson. "Having one sensor that can give high-accuracy navigation information to a crew member, or an automated guidance, navigation and control system, from three miles away to within seven feet is unprecedented."

On shuttle mission STS-134 planned for July, the new system will be demonstrated during docking, undocking and re-rendezvous operations. Data will be collected and the crew will be able to monitor the data through a STORRM software application on the shuttle computer. In addition, screen snapshots of the data will be sent to Mission Control at Johnson by slow scan video for the STORRM team to evaluate the data real time.

STORRM Mounting Concept Image Courtesy NASA

Under direction of the Orion Project office, teams from NASA Langley, NASA Johnson, and industry partners Lockheed Martin and Ball Aerospace worked together in a short time to develop and test the prototype to support the STORRM Development Test Objective. Engineers at Langley are responsible for engineering management, design and build of the avionics, DTO computer hardware and reflective elements. They are also responsible for the integration, testing and certification of these components. NASA Johnson is responsible for program management, technology evaluation, flight test objectives, operational concepts, contract management and data post-processing. Industry partners Lockheed Martin Space Systems and Ball Aerospace Technology Corporation are responsible for the design, build and testing of the VNS and docking camera.

FMI: www.nasa.gov/topics/shuttle_station/index.html