Reply to post: Re: Whose boosters?

Re: Whose boosters?

All four stages were Russian designed and built - first three are the Soyuz rocket system, fourth was Fregat. The Soyuz and Fregat vehicles are built by two different Russian companies.

The fault was in the Fregat vehicle, simple version is this: They ran a liquid helium pipe (very, very cold) next to the hydrazine pipe, which resulted in the hydrazine fuel freezing solid and cutting off thrust.