GPM Performs Yaw Turn, Continues Calibration

On March 17, the team executed GPM's first scheduled yaw turn to turn the orientation of the spacecraft 180 degrees. Yaw is the left/right orientation in the horizontal plane of the spacecraft's motion. The spacecraft is now "flying backwards." Yaw maneuvers will be performed approximately every 40 days for spacecraft thermal control, as the angle between the spacecraft's orbit and the sun changes. This keeps the side of the spacecraft that is designed to remain cold from overheating. Yaw maneuvers are performed primarily using the spacecraft's reaction wheels. March 19, the team performed a

Calibrating Thrusters, Verifying Science Data

The Global Precipitation Measurement mission's Core Observatory is performing normally. On March 12, the GPM Core Observatory fired its thrusters for a 30-second check-out of their performance. The burn, called a delta-v, changes the velocity of the spacecraft to adjust the altitude of its orbit. This week's short maneuver did not greatly alter the satellite's orbit but was used instead for further calibration of the thrusters. Functional checkout activities and internal calibration of the Dual-frequency Precipitation Radar continued this week. Both DPR and the GPM Microwave Imager have begun

DPR Activated, in Checkout

On Saturday, March 8, just after 10 a.m. EST, the second of the two science instruments aboard the Global Precipitation Measurement (GPM) mission's Core Observatory was activated, and the teams in the mission operations center and launch support room at NASA's Goddard Space Flight Center in Greenbelt, Md., began the instrument's checkout period. DPR functional checkout activities and internal calibrations continued on Sunday and will continue this week and next. DPR data is being sent through the Precipitation Processing System at Goddard to the Japan Aerospace Exploration Agency (JAXA)

GPM Checks Out Thruster Performance

Today, the Global Precipitation Measurement mission Core Observatory successfully fired its thrusters for five seconds to check out the thruster performance. This type of maneuver, called a delta-V, changes the velocity of the spacecraft to adjust the altitude of its orbit. Today's delta-V resulted in only a very slight change in the orbit, but will help the GPM team assess and calibrate the thruster performance. By contrast, yesterday the team pulsed each maneuvering thruster 3-6 times, but for only 100 milliseconds each time. This was long enough to make sure the thrusters were working, but

GMI Reflector Deployed

Following activation and warm up of the Global Precipitation Measurement Microwave Imager (GMI) electronic systems, the team at NASA’s Goddard Space Flight Center in Greenbelt, Md., deployed the main reflector of the U.S. science instrument for the GPM Core Observatory. A significant step was also achieved today in the activation of the science instrument provided by the Japan Aerospace Exploration Agency (JAXA) with the turning on of the controller for the Dual-Frequency Precipitation Radar (DPR). The DPR will provide three-dimensional information about precipitation particles derived from

Checkout of the GPM Core Observatory Continues Normally

Friday evening, GPM flight controllers at NASA Goddard began using the satellite’s High Gain Antenna system for high-rate data rate transmissions through NASA’s orbiting fleet of Tracking Data Relay Satellites. Having high-rate data flowing through the TDRS system allows the spacecraft recorder to be downloaded more frequently. During science operations, TDRS communication will allow availability of science data within 3 hours of measurement. Just after 11 a.m. EST on Saturday, March 1st, the flight team began the activation of one of the two main science instruments on the GPM observatory –