|Posted on Feb 20, 2009 08:51:54 PM | Eric Ianson | |||
The process of building and launching a NASA satellite involves establishment of stringent requirements, rigorous design reviews, and robust ground based test programs. Today, one of the final tests was performed on the OCO system. This event, the Combined System Test (CST), was an integrated electrical test of the launch vehicle working with the OCO spacecraft. The CST went well and all systems remain a “go” for a Tuesday morning launch.
Despite all the efforts to ensure mission success, the very nature of space missions carries some degree of risk. Accordingly, NASA must be prepared in the unlikely event that something goes wrong. The second of today’s big events at the launch site was part of this preparation process. All of the key players for launch day gathered at Vandenberg AFB to run through a contingency exercise. The goal was to make sure that everyone understood their roles in the event of serious problem. Having been directly involved in the development of these contingency plans, I’ve gained a new appreciation for the complexity of this effort. In the end though, these are plans we hope to never have to put into action.
With each post in this blog, I am going to try to put in a little information to help people better understand NASA missions, and OCO in particular. Today, I’d like to focus on the last “O” in OCO...which stands for “Observatory”. An observatory is comprised of a spacecraft and science instruments. The spacecraft is often referred to as the “bus”. The instruments can be thought of as the bus passengers.
OCO’s spacecraft bus is a LEOStar-2, built by Orbital Sciences Corporation. The LEOStar-2 line of spacecrafts has been successfully used by NASA several times in the past...most recently on the AIM mission. While all LEOStar-2 spacecrafts have a common basic architecture, each mission has unique attributes, depending on the orbit and instrument requirements.
Some observatories are large and carry multiple instruments, which have to share observatory resources and measurement opportunities. OCO is a very focused mission, with a single instrument. Because the OCO instrument gets a solo ride on the bus, it enables nearly continuous carbon dioxide measurements to be taken. This exclusivity also provides OCO scientists the ability to request changes in the observatory’s orientation, to point the instrument at locations of interest on the Earth.
I’ll have another update tomorrow on the events of the day as well as a little info on what OCO will be measuring. And as a reminder, NASA will provide live countdown coverage on launch night at:
Tags : Earth Science, General, OCO