The Japanese Aerospace Exploration Agency’s (JAXA) HTV-3 “Kounotori” spacecraft was released by the International Space Station’s (ISS) Canadarm 2 robotic arm on time at 11:50 a.m. EDT – shortly afterward things, in the parlance of engineers, went “off-nominal” with the cargo vessel entering into a ACU (Abort Control Unit) abort.
The abort was posigrade without attitude control. The HTV-3 regained attitude control and is on a safe abort trajectory that has placed it above and behind ISS.
JAXA is not sure why the abort happened and is tracking HTV and will report on the spacecraft’s status as information presents itself.
The Abort Control Unit is a separate computer in the HTV that can do nothing but main engine open-loop abort maneuvers.
HTV-3 was launched on July 21, 2012 on a resupply mission to the orbiting laboratory. With that mission now complete, the soda can-shaped spacecraft will conduct its last de-orbit burn at 12:51 a.m. EDT that will see it plunge back into the atmosphere about a half-hour later. The HTV class of vehicles are not reusable and the Kounotori 3 will burn up in the atmosphere over the Pacific Ocean.