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Gravity Probe B In Science Mission Orbit
Huntsville (SPX) Apr 29, 2004 In its first week on orbit, Gravity Probe B has achieved many successes that will ensure a smooth transition into the science phase of the mission and the best possible experimental accuracy. The spacecraft has already achieved a science mission orbit, within the plane of the Guide Star, I'm Pegasi, and its inclination error is six times better than expected. In the quiet environment of space, the gyro readout system is performing significantly better than it did during any ground testing. All four SQUIDs (Super-conducting Quantum Interference Devices) are fully functional and have detected calibration signals with high precision. Noise levels are below the allowable mission requirements. The electrical power system is fully functional and is providing adequate power for all operating conditions. Eclipse operation (when the spacecraft is in the shadow of the Earth) meets all requirements. There is no evidence of solar array motion that might disturb the experiment. All other spacecraft subsystems are fully functional. All four gyros have been checked out and are performing well. They have all been electrically suspended in analog mode; digital suspension activities will commence shortly. The team is in the process of updating data tables for the Gyro Suspension System (GSS) to aid in achieving digital suspension of the gyros. The spacecraft's Attitude Control System (ATC) is maintaining a stable attitude (relative position in orbit-pitch, yaw and roll). We expect to lock onto the Guide Star, I'm Pegasi, within a few days, after completing on-orbit re-calibration of the spacecraft's 16 micro thrusters. During thruster re-calibration, it was observed that one of the redundant micro thrusters was stuck partially open. It was isolated and removed from the system, and the flow of helium to the remaining micro thrusters has been adjusted to compensate for its removal. Overall, one week after launch, it appears that all of the spacecraft's subsystems are functioning well-meeting or exceeding mission requirements, in preparation for beginning the science experiment. The spacecraft is being controlled from the Gravity Probe B Mission Operations Center, located at Stanford University. Mission operations have demonstrated that the hardware developed for the GP-B mission is performing as planned, and the Stanford-NASA-Lockheed Martin operations team is performing well. The Initialization & Orbit Checkout (IOC) phase of the Gravity Probe B mission is planned to last 45-60 days, after which the 13-month science data collection will begin. This will be followed by a two-month final calibration of the science instrument assembly. NASA's Gravity Probe B mission, also known as GP-B, will use four ultra-precise gyroscopes to test Einstein's theory that space and time are distorted by the presence of massive objects. To accomplish this, the mission will measure two factors -- how space and time are warped by the presence of the Earth, and how the Earth's rotation drags space-time around with it. Community Email This Article Comment On This Article Related Links Gravity Probe B SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Space Technology News - Applications and Research
Industry Team Achieve New Communications Technology With AESA Radars
Baltimore MD (SPX) Jan 12, 2006A team comprised of three leading US aerospace and defense contractors has demonstrated an innovative technological use of active electronically scanned array (AESA) radars for high-bandwidth communications. |
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