An attempt to re-dock an unmanned Russian Progress supply ship with the International Space Station was aborted by the ship's flight computer Monday night when a new rendezvous system failed to operate as expected, flight controllers said.
By design, the spacecraft ended up on a passive return trajectory that will permit another docking attempt later this week, after engineers have a chance to diagnose what went wrong. The station's six-member crew was never in any danger, officials said.
The Progress M-15M spacecraft was undocked from the station's Pirs module Sunday afternoon and directed to back away to a distance of about 100 miles. The goal of the exercise was to test a new KURS rendezvous antenna that is designed to replace three antennas currently used by approaching Progress and manned Soyuz spacecraft to "lock on" to space station navigation beacons.
But Monday evening, with the Progress M-15M spacecraft at a distance of about nine miles from the station, the approach was aborted by the craft's flight computer around 8:23 p.m. EDT.
"Docking was aborted...when the new KURS-NA automatic rendezvous system, which was being tested tonight, was set to be activated," said Dan Huot, NASA's mission control commentator. "A failure of an unknown nature occurred and caused the Progress's on-board computers to self abort and put the spacecraft into a passive abort trajectory."
Following that trajectory, the spacecraft passed about two miles below the space station at 9:37 p.m.
"Following this approach, it'll pass into a long loop back behind the International Space Station while Russian flight controllers ... continue to evaluate the problem," Huot said.
Russian flight controllers could make a second attempt to dock the spacecraft Tuesday evening, but it appeared more likely re-docking would slip to this weekend, after the arrival of a Japanese cargo ship launched last Friday. Station astronauts plan to use the lab's robot arm to pluck Japan's HTV-3 vehicle out of open space this Friday so it can be berthed to an Earth-facing port on the forward Harmony module.
"As of right now, Russian ground controllers (are) indicating the next attempt for this Progress to dock to the International Space Station is likely to be this upcoming weekend, after that HTV-3 vehicle is berthed," Huot said. "But that final decision has not been made yet."
A similar docking failure occurred in July 2010 when an approaching Progress unexpectedly went into a passive abort mode after telemetry between the spacecraft and the station was lost. Russian engineers later blamed the failure on electrical interference between the automated KURS rendezvous system and a television transmitter that is part of a manual backup system.
That spacecraft was successfully attached to the station two days later.