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Gravity Probe B

Testing Einstein's Universe


The Vatterfly exhaust and leakage gas valves have successfully completed their acceptance testing and have been installed onto the flight probe. The probe's buffer lines (to mitigate the risk of cryocontamination), Vatterfly valves, spinup valves, and caging valves have been successfully leak tested on the probe, thus completing all operations on the probe prior to the start of probe/dewar integration.

Dewar preparations have been completed for the probe/dewar integration. The steps performed here include the removal of the baffles, removal of ice (air) within the dewar, installation of the glove box, and the installation of the well cover.

The probe has been delivered to FIST ops and is currently on the genie lift in preparation for probe/dewar integration.

The reworked UV cage was successfully integrated into the Aft ECU. Upon completing the thermal vacuum bake out the Aft unit will be acceptance tested.

Initial assembly of the 4 aft GSS boxes is complete, and APUs have been mated to them. One of these boxes has completed initial test. The three boxes that have not yet been tested will undergo testing this week. Following test, they will be returned to Ames for final closeout (staking). The longest lead item for the forward boxes, the high voltage board, has been expedited with the vendor. Delivery is expected within 9 weeks.

Photo: The Vatterfly Valves during installation

The flight Sunshade has been delivered to the LM B/205 high bay for pre-ship functional testing prior to the payload acoustic test.

John Thatcher and his ECU team have successfully integrated the UV cage delivered by Stanford into the Aft ECU. The Aft unit is being baked out and then the UV system will undergo testing. The Aft unit Vatterfly boards have been sent to Zentek for rework; upon return they will be tested and conformally coated. The Aft ECU will then be ready to resume protoqual testing in mid-Oct. The Fwd ECU is in pyro shock testing.

Three of the SRE power supply boards have been tested and were sent to conformal coating. The remaining boards are in test. Upon checkout of the boards, they will be conformally coated and the integrated Aft and Fwd units will undergo a systems level MQA at the end of October prior to resumption of protoqual/acceptance testing.

Photo: LM technician Bud Swihart with the Sunshade installed in its shipping container in LM B/205.

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