Failure to dock the Japanese Orihime and Hikoboshi spacecraft in orbit on 13-14 August was the result of attitude control difficulties. The cause was either a jammed thruster, software or electronic errors, say officials in Tokyo.

The two spacecraft had successfully undertaken rendezvous and station-keeping manoeuvres as part of the $220 million ETS 7 programme. The docking was cancelled after three attempts.

A successful automatic docking was achieved on 7 July, the first such event by a nation other than Russia or the USA. The US Gemini 8 made the first manned docking in 1966 and Russian unmanned Cosmos satellites linked up in 1968. These dockings were made by spacecraft launched separately, while the Japanese vehicles, launched on an H-2 booster in November 1997, were originally one spacecraft which were subsequently separated.

Officials say that further ETS 7 docking attempts are unlikely, but overall the tests were deemed to be a success, particularly the verification of the global positioning and radar systems.

Source: Flight International