Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo

 

Unsupported browser: Your browser does not meet modern web standards. See how it scores »

{ action.text }

Spacecraft landing on the Moon and Mars have yet to be able to choose their landing sites: they touch down wherever their trajectories take them. But the most scientifically rich terrain also tends to be the most hazardous. Now NASA is developing an optical sensor that will, for the first time, allow spacecraft to identify safe landing locations and navigate toward them.

The technology is a light detection and ranging (LIDAR) system that sends three continuous beams of laser light to the surface. It measures the properties of the light that bounces back to determine the velocity and position of the spacecraft relative to the surface, in three dimensions. “It is much more accurate than any other available, similar technology in terms of determining your coordinates relative to the surface, and it is going to be revolutionary in that area,” say Bob Reisse, the project manager for the system at NASA’s Langley Research Center, in Hampton, VA.

Traditional LIDAR uses short pulses of laser light and measures the time it takes them to return to the emitter. Instead, the new system measures the Doppler shift–the change in frequency and wavelength–of the return beam. “The beam has to be more or less continuous for long enough to make the measurement,” says Reisse. “We also need [the beam] to be stable, and continuous lasers are much more stable than continuous bursts.” In addition, whereas traditional LIDAR uses one beam, the new system uses three. “Essentially, it is an entirely different technology,” Reisse says. The combination of the Doppler shift measurement and the added beams allows the spacecraft to calculate its velocity down to the order of centimeters per second, and its position to the order of centimeters, at a range of one to two kilometers from the planet’s surface, says Reisse.

2 comments. Share your thoughts »

Credits: Tony Landis/NASA

Tagged: Communications, space, lasers, spacecraft, lunar landing, optical sensor, LIDAR

Reprints and Permissions | Send feedback to the editor

From the Archives

Close

Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me