Progress 96 Launch: Soyuz 2.1b Sends 2.8 Tons to the ISS

Progress 96, an unpiloted cargo craft carrying 2.8 tons of food, fuel and supplies, lifted off on a Soyuz 2.1b booster from pad 6, site 31 at the Baikonur Cosmodrome in Kazakhstan at 9:33:54 a.m. Eastern Time on Sept. 16, bound for the International Space Station and its Expedition 75 crew. Mission Control Houston described the climb as a flawless ascent to preliminary orbit.

A launch timed to the station's orbit

The liftoff time was set so that the rotation of the Baikonur launch pad and the Earth's rotation carried the pad into the plane of the station's orbit. The station orbits about 260 miles above the Earth, inclined 51.6 degrees to either side of the equator. At launch it was flying over the South Central Pacific Ocean. In Baikonur it was 6:33 p.m., about 23 and a half minutes before sunset, with clear skies and temperatures in the low 80s Fahrenheit.

Countdown

The Soyuz had been rolled out to the pad on a railroad car on Sunday and raised upright. The Russian State Commission gave final approval for fueling several hours before launch. At about T-1 minute the rocket went on internal power. The first umbilical tower retracted at T-35 seconds, and the second about 17 seconds later, which started the automatic engine start sequence. The launch key had been inserted in the blockhouse about five and a half minutes before liftoff, moving the sequence into its final automatic mode.

The ascent

First stage separation was confirmed with the strap-on boosters separating in what is known as the cross of Korolev. Second stage shutdown was planned at 4 minutes 36 seconds, when the booster would be 104 miles up, 140 miles downrange and travelling more than 8,700 miles per hour. The third stage then burned until shutdown at 9 minutes 11 seconds. Solar arrays and navigational antennas were deployed, and controllers confirmed both. Russian flight controllers outside Moscow took over the journey after separation.

The rendezvous

Progress 96 began a 3-day rendezvous spanning 49 orbits, with the first delta velocity burns about three and a half hours after launch to raise its altitude toward the station's. Docking to the Poisk module on the space-facing side of the Russian segment was scheduled for Saturday at 9:46 a.m. Eastern Time. If the Kurs automated rendezvous system had a problem, Pyotr Dubrov and Anna Kikina were to take manual control from the Toru workstation in the Zvezda service module.

The crew waiting aboard

Expedition 75 was led by NASA's Jessica Meir, with Anil Menon and Jack Hathaway of NASA, Sophie Adenot of the European Space Agency, and Roscosmos cosmonauts Pyotr Dubrov, Anna Kikina and Andrey Fedyaev. Meir, Hathaway, Adenot and Fedyaev were weeks from returning on the Crew 12 SpaceX Dragon Freedom after about a seven-month mission, and the Crew 13 team was preparing to launch on the Dragon Grace.