Progress 47 nears ISS docking. Image Credit: NASA TV
Russia's unpiloted Progress 47 supply ship re-docked with the International Space Station late Saturday, successfully completing a test of the new KURS-NA automated docking system on the second attempt.
The two spacecraft linked at 9:01 p.m., EDT.
The M-15M freighter aborted its first attempt to re-dock late July 23, when the prototype avionics upgrade failed an activation self-test at a separation of 161 kilometers, or about 100 miles, from the station.
In between the two attempts, Russian experts traced a potential cause of the abort to low temperatures within the freighter. Internal heaters were commanded by Russian flight control teams to warm the avionics to 22 degrees C for Saturday's link up. At 7:01 p.m., EDT, the KURS-NA aboard the capsule activated as intended at the point it failed the July 23 self test.
NEW KURS-NA rendezvous system eliminates four antennas, upgrades electronics. Image Credit: NASA
As the capsule closed within 15 kilometers, the passive and active rendezvous systems on the station and the Progress 47 exchanged comparable range and closing rate data, generating additional confidence for a successful outcome.
The flight test is part of a plan by the Russian federal space agency, Roscosmos, and contractor RSC Energia to equip Soyuz crew transport as well as unpiloted Progress re-supply craft with the upgraded rendezvous system, potentially by 2014. The new system features four fewer antennas, upgraded electronics and a lower power requirement than the current avionics. The new antenna configuration removes a potential docking obstruction as well.
The Progress 47 re-docked to the station's Russian segment Pirs module for what will be a brief final stay.
The freighter reached the station initially on April 22, and all of its nearly three tons of supplies were off-loaded before it undocked on July 22 for what was intended to be an overnight flight test of the new rendezvous system.
Progress 47, now filled with trash, is scheduled to depart the station for the final time late July 30 and eventually make a destructure re-entry into the Earth's atmosphere. Prior to the final undocking, the station's three cosmonauts will remove the KURS-NA hardware so that it can be returned to Earth on a future spacecraft mission to undergo an engineering analysis.
The July 30 undocking will set the stage for an ISS first.
Russia plans to launch the Progress 48 supply craft on Aug. 1 on a four orbit, six hour rendezvous and docking profile. The typical Progress launch to docking timeline spans 34 orbits, or a little over two days. That remains an option for the Progress 48 mission as well.