Archive for October 16, 2018

10/16/2018 – Ephemeris – Soyuz failure makes for problems for the ISS

October 16, 2018 Comments off

Ephemeris for Tuesday, October 16th. The Sun will rise at 7:59. It’ll be up for 10 hours and 56 minutes, setting at 6:56. The Moon, at first quarter today, will set at 12:36 tomorrow morning.

Last Thursday the 11th a cosmonaut, Alexy Ovchinin and an astronaut, Nick Hague were launched toward the International Space Station by a Russian Soyuz rocket. At about the time the four first stage boosters separated from the second stage, something happened, and the capsule containing the men was weightless instead of being boosted by the second stage of the rocket. The Soyuz has an escape system, so the descent capsule separated from the protective shroud and the orbital module on top of it and the service module below it. To make a landing downrange. The men are safe, but the three persons in the ISS must return by mid-December, whether or not they are relieved as their Soyuz capsule cannot be safely flown after that.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


The above with the exception of the last line is what goes out on the 59 second length of my radio program.  What follows is a more complete explanation of the problems in store for the International Space Station as the Russians attempt to determine the cause of the failure, fix the problem and begin flying again.

Cosmonauts and astronauts visiting the International Space Station generally use the same Soyuz that brought them up and docked to the station to return to the Earth.  It happens that the reaction control thrusters used to orient the spacecraft use hydrogen peroxide (H2O2) as a monopropellant.  It decomposes into oxygen and steam when in contact with a catalyst to provide thrust.  However, hydrogen peroxide is unstable if left to itself, slowly decomposing.  This gives the Soyuz a useful lifetime of about 200 days on orbit.   The current crew of Sergey Prokopyev, Serena M. Auñón-Chancellor, and Alexander Gerst was launched from Baikonur, Kazakhstan on June 8, 2018.  The 200 days runs out in late December.  Their original scheduled return date was December 13th.

Scott Manley on YouTube has more information: