Sensors are highly reliable, especially the high-performance variety used in aviation/aerospace apps. However, human error sometimes interferes. It seems that failure to install angular velocity sensors correctly in the Russian Proton-M rocket resulted in a crash on July 2.
What happened? A source involved with the commission investigating the crash told the Interfax news service that angular velocity sensors were "connected the wrong way round" and delivered incorrect data to the guidance system.
The Russian space agency Roscosmos has not confirmed the cause. A source with links to the commission told Interfax that it is investigating a number of possibilities, including a problem with the navigation system, engine malfunction, and an error in the equipment at launch control.
A Proton-M booster rocket with a DM-03 upper stage and three Russian GLONASS-M satellites sits on the Baikonur Cosmodrome launch pad. (Source: RIA Novosti/Roskosmos press service)
Whether the cause was inverted sensors or something else, three navigation satellites and $1.3 billion of equipment was destroyed in the crash, according to Interfax. Just 17 seconds after takeoff, the rocket rapidly veered off course and tried to correct, but it plummeted towards Earth and exploded on contact only 2.5km from the launch site.
The Voice of Russia radio service said the rocket carried 172 tons of highly toxic heptyl fuel and oxidizer. Interfax said 100,000 residents were evacuated, and efforts are under way to detoxify the soil.