Parts installed “upside down” caused Russian rocket to explode last week

While America was looking forward to the July 4 holiday, the Russian space program was busy putting the final touches on its latest rocket launch. A Proton-M rocket carrying three satellites for the GLONASS navigation constellation (Russia's answer to GPS) launched on July 2, 2013 at 06:38:22 Moscow Time.

Just one problem: the rocket came crashing back down to Earth at 06:38:54—landing in a massive fireball. The crash marked another setback for the beleaguered Russian space program. There were fears that the massive quantity of propellant could leak, potentially creating a very toxic disaster for the local population. And there was no immediate explanation as to why the Proton-M failed so spectacularly, so fast.

But on Tuesday, Anatoly Zak reports on his own site, RussianSpaceWeb.com, that investigators have determined the culprit was the “critical angular velocity sensors, DUS, installed upside down.”