MISR cameras are on!!!!!!!!!

A major step forward in the MISR activation sequence took place this morning, and all went perfectly! A scheduled acquisition of signal from Terra through the TDRSS geostationary satellite system occurred at 6:38 AM PST this morning. Uploading of commands to turn MISR's cameras on, one by one, began almost immediately thereafter. Our team at the EOS Operations Center at Goddard gave the "go" signals at the appropriate intervals and monitored MISR's engineering telemetry during the process. By 6:42 AM all nine cameras were on. Currents and voltages are all reading as expected. Between 6:43 AM and 6:46 AM, commands were sent to turn on the heaters in each of the camera focal planes. The focal planes are the surfaces where the cameras form their images. In film cameras, this is where the film is located, whereas in digital cameras, like those in MISR, this is where the solid-state electronic detectors are located. During science operations, MISR's focal planes will be cooled using "thermo-electric" coolers, and the focal plane heaters will be used to automatically maintain the detectors at a temperature of -5 degrees Centigrade. Right now, however, during the outgassing period the thermo-electric coolers are off and the "set point" for the focal plane heaters has been established as 24 degrees Centigrade. (A set point serves the same purpose as when you set the thermostat in your home.) At 6:53 AM, our operations team verified that they were beginning to see the focal plane temperatures begin to rise. At 6:54 AM, a command to turn on the optical bench heaters with a set point of 34 degrees Centigrade was sent. Although we don't expect the bench to reach this high a temperature, this set point serves the purpose of insuring that the bench heaters remain on throughout the outgas period. Since the cameras are mounted on the optical bench, warming the bench will also cause the cameras to warm up. All of this warming is beneficial because it drives contaminants (such as hydrocarbons and water) out of the instrument into the vacuum of space, and since these contaminants can re-condense on cold surfaces we also keep the cameras warm to prevent this from happening. Telemetry is showing that the optical bench has begun to warm up. At 6:55 AM, our operations team scanned the engineering telemetry once again and declared the entire set of procedures a success. This is wonderful news! Although the cameras are now on, we cannot read out the image data until after upload of the flight software program to the MISR computer. This is scheduled to happen in two weeks when the outgassing period completes. Then, the thermal set points will also be established at the values appropriate for science operations. You can see earlier status reports by checking the "News" link of the MISR web site at http://www-misr.jpl.nasa.gov. David Diner