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National Aeronautics and Space Administration

Goddard Space Flight Center

Astrophysics Science Division | Sciences and Exploration

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Video Footage From 2006 Flight

The 2006 payload included a video camera so we could check the cryogenic antennas for evidence of icing during flight. A protective lid covers the instrument to protect the cold optics during lauyynch and ascent. Once at the float altitude of 37 km (120,000 feet), we open the lid so the antennas can view deep space. Liquid helium cools the antennas to a few degrees above absolute zero -- cold enough that air will freeze solid. The instrument design channels cold helium gas from the main helium tank to prevent air from freezing onto the antennas.

Sky port and antennas

Frozen Air, Open Aperture

The image above was taken on the ground prior to flight It shows the dewar mouth from the approximate vantage point of the video camera, mounted above the dewar and off to one side. The sky port is oriented to allow one cluster of antennas to view the sky.

Sky port and antennas
The video clip above shows the payload as the carousel moves the sky port from the large 3 GHz antenna to a second position over the smaller 5 and 8 GHz antennas. The "steam" coming from the dewar is solid nitrogen condensation from the nearby atmosphere. It's the same idea as "seeing your breath" on a cold winter morning, but here we're not seeing water vapor condensing -- it's the nitrogen in the air itself!

Note that the condensing nitrogen flows away from the sky port and the antenna. By design, the dewar cranks out over 5 cubic meters of helium gas per second throughout the flight. This outflow of cold gas keeps unwanted condensation away from the critical antenna opening.

If you look carefully at the outer edges of the frame, you can see city lights on the ground below. The payload slowly spins counter-clockwise, so the lights appear to move in a clockwise direction.

A Wild Ride

Sky port and antennas
The second video clip shows the payload tumbling as it is cut down from the balloon to begin its descent to the ground some 120,000 feet below. The camera is looking down at the protective lid which now covers the antennas. A slight jolt signifies that a set of explosive bolts have fired to cut the payload from the balloon above. The payload and attached camera free-fall for a few seconds, until the parachute suddenly opens. Talk about a wild ride!