Russian flight controllers are scrambling to determine why the Progress 38 (M-06M) resupply spacecraft failed to dock with the International Space Station today, sailing past the orbiting complex as the six astronatus on-board watched during a few heart-stopping moments before it was determined that craft automatically aborted its rendezvous and guided itself safely past the station instead of careening out of control.
FREE VIDEO PROGRESS-38 DOCKING IS ABORTED • WATCH PROGRESS-38 LAUNCH • WATCH ALL-ACCESS MEMBER VIDEO DOWNLOADS PROGRESS-38 DOCKING IS ABORTED • DOWNLOAD JULY 2, 2010 ISS UPDATE • DOWNLOAD JUNE 30, 2010 ISS UPDATE • DOWNLOAD PROGRESS-38 LAUNCH • DOWNLOAD After automatically aborting its docking procedures, Progress 38 flew past the station at a distance of approximately two miles as its designed to do in this kind of scenario. The complex and its six residents were never in any danger as the supply ship drifted by. "The Progress literally flew past the station, but at a safe distance from the outpost," said Rob Navias from NASA's Mission Control in Houston. "The station crew reported seeing the Progress drift beyond their view, as they worked to reestablish telemetry with the spacecraft." Carrying 1918 pounds of fuel, 110 pounds of breathing oxygen along with 220 pounds of water and 2667 pounds of science equipment and supplies such as clothing for the crew, the Progress spacecraft was supposed to rendezvous and dock automatically at 12:58 p.m. EDT, two days after its launch from the Baikonur Cosmodrome. Instead, the crew will have to wait at least a couple more days for the craft's arrival if the problem that prevented docking today can be resolved. "It's been officially decided that there will be no docking today," Russian mission control told the crew earlier today. Rendezvous was called off approximately 25 minutes before the scheduled docking time when the automated Kurs docking system on the Progress spacecraft lost its communication link with the space station. This caused the ship to automatically abort its rendezvous and place itself in orbit a safe distance in front of ISS to await further instructions. "We see the vehicle and it keeps sliding behind and moving toward the front part of the station," said Expedition 24 Commander Alexander Skvortsov. "It's drifting away from us, it's rotating and also it's moving away from us. We are moving with service module forward and it's moving in the same direction but it's going farther and farther away from us." With docking called off for the day, flight controllers are continuing to troubleshoot the communication problem and decide when, or if, Progress 38 will be able to make a second attempt. "They're in the process of evaluating what may have caused a loss of telemetry between the Progress 38 cargo ship and the Zvezda service module about 30 minutes or so before its expected docking," Navias said. "That exchange of data between the radio beacons on the active side of the system, which is the Progress, and the passive side of the system, which is the Zvezda in this case, provides the distance between the two vehicles and the rate of closure between the approaching vehicle and the docking target so the computers can be updated on the Progress itself for its final approach for a linkup at a rate of about one tenth of a meter per second," he said. "In this case, that telemetry link was lost for unexplained reasons. The Progress aborted its automated rendezvous and flew a safe distance past the International Space Station and now is maintaining an opening rate." In use for decades, the Progress resupply spacecraft has a long history of reliably serving not only the International Space Station, but also Russia's earlier Mir station with its automated docking system. Progress outwardly resembles the manned Soyuz spacecraft. The Soyuz comprises propulsion/instrumentation, crew descent and orbital modules. The main difference with Progress is the middle section is outfitted for carrying cargo instead of people. Another difference is that, while the Soyuz descent module re-enters the atmosphere and lands with the crew inside, Progress burns up completely when it de-orbits. On one occasion, the commander of Mir was ordered to conduct a manual docking and the craft flew out of control and collided with the station, puncturing a hole in one of its modules and nearly forcing the crew, including NASA astronaut Michael Foale, to evacuate in their Soyuz. That is the only time in history that a problem with Progress has threatened the safety of the crew onboard. Progress has two docking modes, both of which are certified for use with ISS. Under normal circumstances, the Kurs system handles all of the docking procedures autonomously while the astronauts monitor. However, if that system fails, there is the Telerobotically Operated Rendezvous Unit (TORU) which allows the crew to manually dock the spacecraft using controls and televisions on the station. Each rendezvous operation uses up limited fuel supplies on Progress - fuel that is used during its time docked with the station for orbit adjustments and reboost. The spacecraft also has to keep propellant in reserve for undocking from the station and then de-orbiting itself. If too much propellant is used up on repeated docking attempts and station-keeping, it's possible the spacecraft will run too low on fuel and have to be ditched out of orbit, although the chances of that becoming necessary are considered remote. It's possible that another docking attempt could be made in a few days, using either Kurs or TORU, but first flight controllers need to understand what happened today and ensure that the same problem doesn't crop up during the next go-around. (The Spacearium / SpaceflightNews.net)
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