Overview

The Orbiting Carbon Observatory (OCO) was a NASA Earth science satellite mission designed to produce high‑precision, global measurements of atmospheric carbon dioxide (CO2). Its primary aim was to map the distribution of atmospheric CO2 at fine spatial scales so scientists could better locate natural and human-related sources and sinks and improve models of the global carbon cycle. OCO was intended to be the first U.S. mission dedicated specifically to measuring column‑averaged CO2 from orbit with the spatial resolution and precision required for carbon cycle studies.

Instruments and measurement approach

The spacecraft carried high‑resolution spectrometers that measured sunlight reflected from Earth's surface in several narrow near‑infrared bands where CO2 and molecular oxygen absorb. By comparing the relative absorption across these bands, the mission sought to retrieve the total column‑averaged CO2 concentration (a commonly used quantity in atmospheric carbon research). The instrument concept emphasized precise, repeatable observations to detect regional enhancements associated with emissions and uptake.

Launch, failure, and immediate aftermath

OCO launched on February 24, 2009, aboard a Taurus launch vehicle. During ascent the rocket’s payload fairing (the protective nose cone) failed to separate as planned. The extra mass and altered aerodynamics prevented the booster from imparting sufficient velocity for orbital insertion. As a result, OCO did not achieve orbit and reentered the atmosphere, falling into the southern ocean near Antarctica and the Indian Ocean region. The loss prompted reviews of launch hardware and mission risk practices and led NASA to accelerate plans for a replacement mission.

Goals, importance, and legacy

Although the original spacecraft was lost, OCO’s scientific goals influenced subsequent Earth science missions and the international effort to quantify the global carbon budget. Precise, space‑based CO2 observations are valuable for improving climate projections, informing policy discussions on greenhouse gas emissions, and refining understanding of ecosystem and ocean carbon uptake. The need identified by OCO motivated follow‑on missions and collaborations to sustain long‑term CO2 monitoring from space.

Successor and continuing work

NASA developed a follow‑up mission that implemented the same measurement approach and expanded operational support. Data from the successor mission have been used alongside other satellite and ground‑based measurements to create maps of atmospheric CO2 and to study regional emission patterns. The OCO program is often cited as an example of how a high‑priority scientific objective can survive a setback and continue to advance through revised efforts and international partnerships.

  • Primary objective: Map global CO2 distribution at high precision and spatial resolution.
  • Measurement method: High‑resolution near‑infrared spectroscopy of reflected sunlight.
  • Outcome: Lost in 2009 launch failure; successor missions carried forward goals.
  • Further reading: NASA mission pages and scientific literature summarize the design and lessons learned.