In the pre-dawn hours of July 2nd we were anxiously awaiting the booster ignition of the Delta II rocket that would propel the OCO-2 (Orbiting Carbon Observatory) spacecraft into orbit. After a fairly quiet and uneventful countdown the engines ignited and filled the dark marine layer covering the launch pad with a bright orange glow. The launch rocket quickly climbed in altitude and within seconds was no longer visible from the ground level, only cameras positioned above the marine layer could still see the vehicle and the smoke trail it left in its wake. After what seemed like an eternity, the on-orbit coast between the 1st burn of the Delta II upper-stage and the very short 2nd burn the spacecraft was seperated from the launch vehicle and started entering into operation. Our job was now officially over, the spacecraft was delivered safetly to orbit. But what happens next?
Check-Out & Maneuver to Operational Orbit
The work of the launch team may be over, but the fun is just starting for the spacecraft team. There are all kinds of exciting activities going on in the spacecraft Mission Operations Center (MOC), including sub-system turn-on and check-out, system and instrument calibrations and manuver planning. Yes, I said maneuver planning. The spacecraft still must change it's orbit and get into the A-Train. The A-Train is short for "Afternoon Contellation". A Constellation is another name for a group of spacecraft flying relatively close to one another (see photo below of the A-Train Constellation).
It is called the "Afternoon Contellation" because this group of satellites operate in an orbit with an inclination near 90 degrees, which means they fly over the North and South poles of the Earth. As these spacecraft fly in their orbit and they cross the Earth's Equator going from South to North they cross the Equator when it is aproximately 1:30 pm local time at the point directly below the spacecraft on the Earth. As the spacecraft travels around it's orbit and comes 360 degrees aroung the Earth (which takes about an hour and a half) the Earth rotates under the spacecraft such that even though an hour and a half has passed the point directly below the spacecraft is still at 1:30 pm local time (but it is a different location on the Earth). OCO-2 crosses the Earth's equator twice per orbit, but it is the crossing that goes from South to North that the Constellation is named after. Each time it cross the Equator from South to North it is 1:30 pm in the afternoon directly below the spacecraft. This gives each of the spacecraft in the A-Train a consitant viewing condition in which to take scientific measurements. For more information about all of early orbit activities I recommend reading the OCO-2 blog called Blog By Randy, which is written by a member of the spacrcraft team on a daily basis. This is great way to keep up with everything the team is doing.
How To Follow The OCO-2 Mission
I'll write another post about the OCO-2 mission once it has reached it's final orbit in the A-Train and started it's science mission. In the mean time below are ways you can follow the OCO-2 mission:
- The NASA Earth Right Now Shareables flickr account has images from all of the NASA Earth Observing spacecraft including OCO-2.
- The JPL OCO-2 News site has news stories on OCO-2
- Follow OCO-2 on Twitter
- The NASA OCO-2 news site
And finally I leave you with my favorite OCO-2 launch photo.