Electrical circuit glitch believed caused failure of Japan's small rocket after launch

An electrical circuit problem may have led to the recent failure of the launch of the world’s smallest rocket capable of placing a satellite into orbit, Japan’s space agency said Monday.

The No. 4 vehicle of the SS-520 series lifted off from the Japan Aerospace Exploration Agency’s space center in Kagoshima Prefecture on Jan. 15. But the agency aborted ignition of the second stage after it lost communication with the rocket 20 seconds after liftoff.

The agency said it believes the cladding of electric cables was damaged by the vibration and heat of nearby metal parts, leading the cables to directly touch the metal parts. As a result, a short circuit occurred and a data transmission device lost power, it said.

JAXA used commercially available components found in home electronics and smartphones for the rocket to demonstrate how the cost of placing satellites in orbit could be reduced.

Agency associate professor Hiroto Habu, however, indicated that there were no problems in the use of the commercial components.

“Civilian items were introduced based on the assessment criteria and test methods we have used before,” he said.

Launches of SS-520 rockets have succeeded twice in the past. The latest vehicle was different from previous ones in that it had thinner electrical cables and used different material to place the cables as part of efforts to reduce weight, according to JAXA.

Habu said the rocket design was “appropriate,” while adding that “something beyond expectations” may have occurred through multiple factors. But he also said electrical cables and material used for their cladding can be improved.

The rocket — about the size of a utility pole — fell into the sea off the Uchinoura Space Center in Kagoshima Prefecture.