Last Moment Abort for Launch of Russia’s Progress MS-07 Cargo Spacecraft-UPDATE

The launch of Russia’s Progress MS-07 cargo ship to the International Space Station (ISS) was aborted just before liftoff this morning Eastern Daylight Time (EDT) when engine ignition did not occur.  Troubleshooting is underway. The next opportunity is early Saturday morning EDT if the problem can be diagnosed and remedied by then. [UPDATE, October 14: Liftoff was successful this morning. The abort on October 12 occurred when an electrical connector did not retract from the Soyuz rocket 12 seconds before launch.  The computer terminated the countdown.]

ORIGINAL STORY, October 12, 2017: Launch had been scheduled for 5:32 am EDT, but was aborted  “in the last minute” of an otherwise trouble-free countdown according to NASA’s Rob Navias who was anchoring NASA TV’s coverage of the launch:  “The engine ignition never occurred on the Soyuz booster.”  The next opportunity for launch is Saturday morning at 4:46 am EDT.

Launch of Russian cargo vehicle has been scrubbed for today. Next opportunity no earlier than Oct. 14 at 4:46am ET: https://t.co/FRrjhIw77o pic.twitter.com/ICIkjkZNmq

— NASA (@NASA) October 12, 2017

Progress launches are relatively routine — this is the 68th Progress to resupply ISS and NASA refers to it as Progress 68 for that reason — but this one was intended to demonstrate a shorter, two-orbit trajectory to reach the ISS.

Beginning with its first space station, Salyut 1, in 1971, the Soviet Union/Russia used a 34-orbit rendezvous sequence for Soyuz crew spacecraft headed to its succession of Salyut and Mir space stations. The first robotic Progress cargo resupply spacecraft was launched to Salyut 6 in 1978 also using the 34-orbit trajectory and that was the standard for Soyuz and Progress spacecraft until 2013.  At that point,  Russia introduced a four-orbit trajectory to shorten the amount of time crew members must spend in the tight quarters of the Soyuz spacecraft from two days to about six hours.

It now wants to shorten the trip time even more to just two orbits or about an hour and a half (each orbit of the Earth takes about 90 minutes at the altitude of the ISS).   What trajectory is used to reach ISS depends in large part on celestial mechanics and the relative positions of the ISS and the launch site (in this case the Baikonur Cosmodrome in Kazakhstan).  If the Progress MS-07 launch occurs on Saturday, it will have to use the 34-orbit route.  It is filled with 2.5 metric tons of fuel, water, compressed gases and equipment.

Soyuz is the name of the launch vehicle Russia uses for launching both Progress and Soyuz spacecraft (and others as well).  There are several variants of the Soyuz rocket and there have been problems with some of them over the past several years.  This is the Soyuz 2.1a version.  A Soyuz 2.1a failure doomed the Progress M-27M mission two years ago.