NASA team advances next-generation 3D-imaging lidar

November 5, 2014 by Lori Keesey, NASA

Nat Gill and Tony Yu are developing new lidar systems for satellite servicing and asteroid retrieval. They are shown here with hardware they have developed for the Goddard Rendezvous Solid-state Scanning Lidar. Credit: NASA/W. Hrybyk
( —Building, fixing, and refueling space-based assets or rendezvousing with a comet or asteroid will require a robotic vehicle and a super-precise, high-resolution 3-D imaging lidar that will generate real-time images needed to guide the vehicle to a target traveling at thousands of miles per hour.

A team of technologists at NASA's Goddard Space Flight Center in Greenbelt, Maryland, now is developing a next-generation 3-D scanning lidar—dubbed the Goddard Reconfiguable Solid-state Scanning Lidar (GRSSLi)—that could provide the imagery needed to execute these orbital dances. "We have made a tremendous amount of progress," said Nat Gill, GRSSLi principal investigator at Goddard. "We have a long way to go, but we hope to validate the GRSSLi system this fall."

The current system has achieved a technology-readiness level of five. In the parlance of NASA engineers, this means that once the team completes this iteration of GRSSLi, the team will be ready to build another system that would undergo vibration and thermal-vacuum testing.

Centimeter-Level Resolution Over a Range of Distances

GRSSLi is a next-generation scanning lidar based on technologies developed by the Army Research Laboratory, which later transferred the technology to Spectrolab, Inc., a wholly owned subsidiary The Boeing Co. The company now markets the instrument as the SpectroScan 3D.

GRSSLi, however, will take 3-D imaging lidar to the next level—all from a small, low-cost, low-weight platform capable of centimeter-level resolution over a range of distances, from meters to kilometers, said GRSSLi Co-Principal Investigator Tony Yu, who received Goddard Internal Research and Development (IRAD) program funding to help advance GRSSLi and its close cousin, a non-scanning 3-D imaging lidar.

The micro-electro-mechanical — or MEMS — mirror at the center of the circuit board provides the scanning function in the Goddard Rendezvous Solid-state Scanning Lidar. Credit: NASA/W. Hrybyk

Equipped with a low-power, eye-safe laser, a micro-electro-mechanical scanner, and a single photodetector, GRSSLi will "paint" a scene with the scanning laser and its detector will sense the reflected light to create a high-resolution 3-D image at kilometer distances—a significant increase in capability over current imaging lidars that are effective only at meter distances. Just as important, the instrument is equipped with onboard "vision" algorithms or software that interpret the three-dimensional image returned by the lidar. These algorithms estimate location and attitude—or in other words, the pose—of a target relative to the lidar.

"The SpectroScan 3D is a low-cost lidar, but it can't provide centimeter-level (less than an inch) resolution beyond 30 meters (~98 feet)," Yu said. "We are retrofitting this lidar system with a high-energy laser system to extend the range to beyond one kilometer." GRSSLi currently has a limited range of about 20 meters (~66 feet), Yu said. This year, the goal is to extend the range to 1000 meters (0.6 miles) by increasing the power of the laser transmitter and adding a more sensitive detector.

Asteroid Close Approaches Also Eyed

The lidar, however, wouldn't be limited to servicing and repairing satellites and other orbiting assets, Yu said. Under the same IRAD task, Yu and Gill are working to advance a non-scanning version of GRSSLi that would be ideal for close approaches to asteroids. "We view the 3-D scanning lidar as an intermediate step to a non-scanning ," Yu said.

This particular instrument would employ a flash lidar, which doesn't paint a scene with a mechanical scanner, but rather illuminates the target with a single pulse of laser light—much like a camera flash. The advantage is the elimination of moving parts that could be prone to failure. A telescope then would capture the returning photons and image them on a photon-sensitive detector array. Each pixel of that array would measure the photons' times of flight to create a 3-D image of the target.

Although flash lidars are available commercially—and, in fact, one is baselined for the Goddard-led OSIRIS-REx mission—they do not produce high-resolution images from kilometer (mile) distances, a capability that would benefit science and military applications, Yu said.

"A need exists for long-to-short range, low-cost, reliable multifunctional imaging lidars, not only for asteroid rendezvous and planetary rovers, but also for satellite servicing," Yu said. "We are making progress, but we do have a way to go."

Explore further: NASA technologists embrace laser instrument challenge

Related Stories

NASA technologists embrace laser instrument challenge

November 18, 2013

In 2007, the National Research Council threw down a challenge: Design a space-based laser altimeter that could measure the height of Earth's surface everywhere to within a mere 10 centimeters—all at 5-meter resolution. ...

Laser radar illuminates the way to deep space

February 23, 2012

This car was not snapped with a camera but scanned by a 3D imaging lidar, the laser equivalent of radar. ESA is developing the sensor as a navigation aid for exploring deep space.

NASA advances world's first spaceborne sodium lidar

October 30, 2013

It's used as a coolant in nuclear power plants and as a desiccant to remove humidity that otherwise would ruin moisture-sensitive products. Found in every cell in the human body, it transmits nerve impulses and regulates ...

Recommended for you

Semimetals are high conductors

March 18, 2019

Researchers in China and at UC Davis have measured high conductivity in very thin layers of niobium arsenide, a type of material called a Weyl semimetal. The material has about three times the conductivity of copper at room ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.