Out-of-synch Computers Cited in Epsilon Launch Abort

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TOKYO — Poor synchronization between flight and ground-based computers caused an anomalous reading that forced the Japan Aerospace Exploration Agency (JAXA) to abort the maiden launch of its Epsilon small rocket, JAXA officials said Aug. 30.

The planned Aug. 27 launch of the solid-fueled rocket was aborted 19 seconds before liftoff from the Uchinoura Space Center after sensors indicated there was an issue with the vehicle’s attitude control system.

During a press conference, JAXA officials said the root cause was a 0.07-second time lag between the rocket’s on-board computer and the ground-based launch control system.

Yasuhiro Morita, JAXA’s Epsilon project manager, said that 20 seconds before liftoff, the on-board computer sent data on the attitude control system to the launch control system. However, the data’s time stamp did not match the clock on the ground-based computer, which therefore flagged the reading as anomalous, triggering the mission abort.

JAXA hopes to make another launch attempt before the end of September, but no official date has been set. The payload on the upcoming mission is JAXA’s Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere (Sprint-A) scientific satellite.