GPM: Engineering Next Generation Observations of Rain and Snow



Art Azarbarzin: In December 2009, we had our CDR and shortly after that we started the manufacturing process for all the components of GPM. After about a year and a half, we started putting the spacecraft structure together and went through the qualification of the structure and, the step after that was installing the harness. The harness for a spacecraft is a component which basically all the wires that we put on the spacecraft that connects all the boxes together with the connections at each end.

Candace Carlisle: We started the integration of the observatory with the delivery of the two instruments: the GPM Microwave Imager and the Dual-frequency Precipitation Radar in early 2012. These were then integrated onto the spacecraft, and we checked everything out to make sure everything works culminating with a Comprehensive Performance Test in October of 2012. Before we launch any spacecraft we do a very lengthy and detailed set of tests to make sure that the spacecraft is going to survive all the environments that it's going to see during the launch and on orbit.

Art: The test program for the observatory is pretty rigorous and that's because once we get into space, we have only one shot at this.

Candace: The next thing we do is make sure that everything's still working after the full suite of environmental tests. So we do deployments of the solar arrays and the GMI and the High Gain to make sure those still work just the same way they did before we went into environments.

Art: The GPM Observatory is about 3900 kilogram spacecraft, fully loaded. Very large spacecraft. And the larger the satellite is, just the logistics of moving them from one location to another is much more complicated than when you're dealing with a small satellite. That's why spacecrafts or observatories like GPM Core Observatory take longer for us to complete the manufacturing and testing and all the environmental testing we need to do at the end.

Candace: Here at Goddard we have about 300 people working on GPM. About 100 civil servants and about 200 contractors. That, in addition to a number of people at the Japan Aerospace Exploration Agency who worked on the DPR instrument and at Ball Aerospace who worked on the GPM Microwave Imager instrument.

Art: Once we complete the GPM Core Observatory testing inside our high bay, we get the spacecraft prepared for shipment. Then our next step is to transport it to Andrews Air Force Base and install it on the C-5 and then take it to Tanegashima Island.