After multiple delays, Progress MS-05 set for launch
Russia’s state-run corporation for space activities, Roscosmos, is in the final stages of preparing to launch the Progress MS-05 cargo resupply spacecraft to the International Space Station (ISS).
Progress 66P – also known as Progress MS-05 – will launch at 12:58 a.m. EST (05:58 GMT) Feb. 22, 2017, atop the final Soyuz-U rocket from Baikonur Cosmodrome in Kazakhstan.
Russia’s Progress spacecraft is an uncrewed variant of the crewed Soyuz vehicle and is capable of fully automated flight and docking with the Russian segment of the ISS.
Progress MS-05 will be carrying 5,401 pounds (2,450 kilograms) of supplies and consumables to the orbiting outpost, including 1,554 pounds (705 kilograms) of propellant.
As with previous Progress missions, MS-05 will embark on a two-day, 34-orbit rendezvous profile with the space station and will likely spend about four months attached to the outpost. Docking with the Pirs module is expected to take place at 3:34 a.m. EST (8:34 GMT) Feb. 24.
The venerable Soyuz-U rocket was tapped to launch the Progress MS-05. The U-variant of the Soyuz line of vehicles has had a long career, notching 764 successful launches over its nearly 44 years of active life.
Not only has the Soyuz-U been in service longer than any other orbital-class rocket, but also it holds the world record for the highest launch rate with 47 flights in 1979. However, the Russian space agency classified the Soyuz-U as “obsolete” in April 2015 in favor of the more modern Soyuz-2.
The Soyuz-U utilizes an older analog flight control system that requires the rocket to be mounted on a rotating platform so that the vehicle could be aimed since it was incapable of performing a roll maneuver.
Like all Russian vehicles based on the iconic R-7 design, the Soyuz-U consists of a core stage with four strap-on liquid-fueled boosters. According to legacy information, each booster is outfitted with an RD-117 liquid oxygen and kerosene-fueled (kerolox) engine, providing 188,502 pounds (838.5 kilonewtons) of sea-level thrust.
The core stage utilizes a single RD-118 engine, providing 182,770 pounds (813 kilonewtons) of liftoff thrust. Like its RD-117 counterpart, it has four combustion chambers fed by a single turbopump assembly.
The primary difference between the two engine models is the amount of control authority the engines provide via their integrated vernier thrusters: the side boosters only have a pair of verniers, whereas the core needs a full range of attitude control and has four verniers.
The second stage, the Blok-I, is powered by a single RD-0110 engine, which provides 67,000 pounds (298 kilonewtons) of vacuum thrust. Like much of the stable of Russian spaceflight components, the RD-0110 has a long history. The RD-0110 was initially introduced in 1965 and is still in production.
Questionable parts cause delays
Progress MS-05 was initially targeted to launch in early February 2017. However, it has seen multiple delays related to the failure of the launch of its predecessor – Progress MS-04.
An investigation determined a failure in the RD-0110’s oxidizer pump caused the assembly to fail and disintegrate. The breakup of the engine caused Progress MS-04 to separate from the stage 22 seconds early.
Failing to achieve orbital velocity, the resupply craft subsequently re-entered the atmosphere, with remnants crashing to the ground in Siberia.
The investigation could not determine a root cause for the failure, though the investigative panel believes the pump was destroyed either from a foreign contaminant or from an improper assembly at the factory.
In a bid to prevent a recurrence of this issue on Progress MS-05, the launch was delayed more than two weeks so that an engine from a different production run could be installed in the Blok-I stage.
The launch of Progress MS-05 will mark the 786th, and final, flight of the Soyuz-U.
Video courtesy of Roscosmos
Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.