NASA's Orbiting Carbon Observatory (OCO) was designed to make measurements of carbon dioxide concentrations
from space with the precision and accuracy required to identify sources and sinks on regions scales (~1,000 km).
Unfortunately, OCO was lost due to a failure of the launch vehicle. Since then, work has started on OCO-2, planned for
launch in early 2013. This paper will document the OCO instrument performance and discuss the changes planned for
the OCO-2 instrument.