Wired Astronauts to Use Motion-based Sensors, Surface Cameras and Orbiter Maps on Return to Moon

NASA-backed researchers envision a combination of motion-based sensors, surface cameras and orbiter maps with a lunar navigation system that gets updated on the fly to help Constellation astronauts returning to the moon in 2020.

"We will have cameras on the lander, cameras on the vehicle, and even on the shoulder, helmet or belly of the astronaut," said Ron Li, a civil engineer the Lowber B. Strange Designated Professor of civil and environmental engineering and geodetic science at Ohio State University.

Li previously designed navigation system upgrades for NASA's Spirit and Opportunity rovers currently making their way across Mars.

When NASA returns to the moon -- the space agency has set a target date of 2020 to do so -- astronauts won't be able to use a global positioning system (GPS) to find their way around, explained Li. The moon doesn't have satellites to send GPS signals.

So NASA has awarded Li $1.2 million over the next three years to develop a navigation system that will feel a lot like GPS to the astronauts that use it, but will rely on signals from a set of sensors including lunar beacons, stereo cameras, and orbital imaging sensors.

The new grant grew out of Li's ongoing development of software for the Mars rovers Spirit and Opportunity. Researchers have learned a lot about navigation from exploring the red planet.  New technology -- sensors, inertial navigation systems, cameras, computer processors, and image processors -- will make the next trip to the moon easier for astronauts.

People are used to having certain visual cues to judge distances, such as the size of a building or another car on the horizon, Li explained. But the moon has no such cues. Getting lost, or misjudging a distant object's size and location would be easy, and extremely dangerous.

He described incidents during past lunar missions when astronauts were traveling to a target site such as a crater, and got within a few yards of it -- but couldn't see the crater because of difficult terrain.

"They were so close, but they had to turn back for safety's sake," he said.

LAOIS will start with 3-D maps of the lunar surface created from orbital views taken by probes such as the future Lunar Reconnaissance Orbiter. Such maps provide the basic topography of the lunar landscape and landmarks such as craters.

The system gets updated as soon as NASA's Orion spacecraft arrives and its Altair lunar lander begins the descent to the moon's surface, with cameras figuratively clicking all the way down. The new images of the landing area will then feed into the navigation system.

"According to our Mars work, during landing you might get descent pictures that give you gradually a higher resolution of the places on the surface," Li told SPACE.com.

Video feeds from astronaut and vehicle cameras would also add to the flow of information. Both the astronauts and their vehicles will also carry motion sensors that constantly update the navigation system with their location — moonwalkers may even sport pedometers similar to those worn by runners.

A lunar communication system consisting of beacons could also help pinpoint the location of astronauts and vehicles for LAOIS.

Navigation tools such as these should help the Constellation astronauts avoid the confusion reported by some Apollo moonwalkers, who had difficulty eyeballing distance and size on the lunar surface without familiar visual benchmarks such as buildings or streets.

"When they land, they kind of lose the sense of orientation, size and shape of objects," Li said. "Usually you overestimate size on the lunar surface."

Getting into the mindset of astronauts requires more than just knowing engineering. Li's interdisciplinary team will examine how best to communicate information to the astronauts from a "cognitive science point of view," and hopefully prevent problems of disorientation.

The system will get its true test within three years, when Li's team will take it out for a test run in the Mojave Desert. A successful demonstration could lead to a flight-ready version getting developed.

LAOIS seems to represent the best immediate solution for moonwalkers, given that the moon lacks the fleet of satellites that make Earth's Global Positioning System (GPS) possible. NASA or other space agencies may eventually launch additional communication and navigation satellites to the moon, but until then astronauts will find their way one step at a time.

Posted by Casey Kazan.

Source Links:

http://researchnews.osu.edu/archive/lunarnav.htm
http://www.livescience.com/space/080730-tw-lunar-gps.html