Electronic Design

Imaging Advances Bring New Eyes To Space Missions

Congratulations to those of you readers who played a role in NASA's major missions this summer. Between the Deep Impact comet exploration, the dramatic return of the shuttle program via the Discovery mission, Cassini's continued exploration of Saturn's moons, and the successful launch of the Mars Reconnaissance Orbiter (MRO), there's been a real renaissance of extraplanetary exploration.

One unifying theme from an electronicsengineering viewpoint is the role played by advanced imaging systems in these explorations. New technologies are changing the face of NASA's missions, enabling scientists to collect and process images in ways heretofore unknown.

HIGH-IMPACT IMAGES - The heart of the Deep Impact mission was high-speed image capture during the impactor's point of collision with Comet Tempel 1. Digital imaging instruments explored the inside of the impact crater on the surface of the comet's nucleus.

The Medium Resolution Instrument captured a true "big picture" of the impact zone via its 10-m/pixel resolution. The High Resolution Instrument married a camera and infrared spectrometer while focusing on two meters of crater area per pixel. Engineers at Ball Aerospace and Technologies Corp. built both instruments, which guided both the flyby spacecraft and the impactor and recorded the scientific data before, during, and after the collision.

Inside the impact instruments were Deep Impact CCDs developed for the mission by engineers at Fairchild Imaging. The 1024- by 1024-pixel Split Frame Transfer CCDs provided rapid image capture capability and the ability to read from four output ports simultaneously to maximize imaging speed. The full impact of the mission won't be understood until the myriad images have been analyzed.

DISCOVERY DRAMA - The shuttle Discovery signaled a winning return for the U.S.A.'s manned space program. The mission's drama focused on the man/machine engineering challenges inherent in repairing the shuttle. Astronaut Stephen Robinson took a spaceride on the International Space Station's robotic arm to remove strips of protruding insulation from the shuttle's underside.

Imaging systems played a key role in pinpointing the shuttle's problems. Engineers who had analyzed the Columbia disaster realized astronauts needed better ways of examining the exterior of their ship. The mechanical arm inside the Discovery's payload bay was fitted with a boom extension from MD Robotics that allowed a 100-ft length for reaching around the spacecraft and getting closeup-views of the orbiter's outer surfaces, including-wing edges, the underbelly, and other previously hard-to-examine areas. A Neptec Laser Camera System was used to inspect for any fractures in the thermal tiles that line the bottom of the shuttle's hull.

The Neptec system's synchronized laser scanning technique generates 3D data that's transmitted back to Mission Control to create 3D images. These images could be zoomed and tilted to reveal even the smallest fractures or defects. The system's key advantage over traditional video cameras is its immunity to changing lighting, which is critical in an environment-where the sun rises and sets 18 times in a 24-hour period.

To capture images of the shuttle during launch, NASA upgraded the tracking camera systems at the launch pads at Kennedy Space Center and along the Atlantic coastline. The Expanded Photographic Optic Control Center (EPOCC), which is the hub for ground cameras, includes 75 cameras positioned for launch photography. Medium-and long-range tracking devices on mobile platforms provided additional film and HDTV images. Nine more camera sites were added to the launch trajectory so engineers could follow the flight more closely. Also, the orbiter's External Tank was fitted with a new digital camera system to take a series of photos as the tank separated from the orbiter.

NASA even tested a new aircraft-based imaging system for more unique camera angles. Known as the WB-57 Ascent Video Experiment (WAVE), it provides images via a 32-in. ball-turret system with reflector telescopes mounted on the nose of two WB-57 aircraft that fly at an altitude of 60,000 ft. Each airplane provides digital imagery of the shuttle over a 400-mile path.

HIGH RES FROM THE RED PLANET- On August 12, the Mars Reconnaissance Orbiter successfully launched on its 72 millionmile journey to reach the Red Planet by next March. It's carrying the largest camera ever flown on a planetary mission, said by NASA to be able to reveal surface features "the size of a dinner table." NASA expects to get more data about Mars from these high-resolution images than from all previous Martian missions combined. The MRO mission will give us a chance to learn more about Mars' history and distribution of water as well as to understand whether our neighboring planet has ever supported life.

Again, congratulations to all of you who contributed to these great scientific endeavors!

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TAGS: Robotics
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