NASA has released its report of what cause the US$273 million Orbiting Carbon Observatory (OCO) to end up at the bottom of the ocean.

The report essentially confirms what was known shortly after the launch: OCO failed to reach orbit because the protective fairing that surrounded the satellite didn’t separate from the rest of the Taurus XL rocket. With the fairing in place, the upper stage of the rocket was simply too heavy to reach orbit, and it instead ended up crashing into the icy waters surrounding Antarctica.

The exact cause behind the fairing failure will probably never be known, but the aptly named “mishap investigation board” has narrowed it down to one of four causes:

*First, is the possible failure of an explosive joint used to literally blow the fairing off the rocket.

*Second, a failure in the electrical subsystem controlling that joint.

*The third possibility would be a failure of the hydraulics that provide pressure to thrusters used to separate the fairing.

*Last but not least, the board postulates that a stray cord snagged in a joint or side rail might have been to blame.

The closing of the mishap investigation will be little comfort to OCO scientists, who are still waiting to see whether NASA will build them a replacement. But the successful conclusion is good news for Glory, an aerosol-observing satellite that is set to launch in January on the same Taurus XL model of rocket.

Image: NASA