astronomy

Orbiting Carbon Observatory 2

Orbiting Carbon Observatory 2 is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Orbiting Carbon Observatory 2 rather than just read about it. In short: Orbiting Carbon Observatory-2 (OCO-2) is an American environmental science satellite that measures carbon dioxide and plant growth on Earth. Launched on 2 July 2014 as a NASA mission, it is a replacement for the Orbiting Carbon Observatory, which was lost in a launch failure in 2009.

Key takeaways

Orbiting Carbon Observatory 2 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Orbiting Carbon Observatory 2 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Orbiting Carbon Observatory 2 from memory before moving on to harder problems.

Reference excerpt

Orbiting Carbon Observatory-2 (OCO-2) is an American environmental science satellite that measures carbon dioxide and plant growth on Earth. Launched on 2 July 2014 as a NASA mission, it is a replacement for the Orbiting Carbon Observatory, which was lost in a launch failure in 2009. It is the second successful high-precision (better than 0.3%) CO2 observing satellite, after GOSAT.

Mission overview The OCO-2 satellite was built by Orbital Sciences Corporation, based around the LEOStar-2 bus. The spacecraft is being used to study carbon dioxide concentrations and distributions in the atmosphere. OCO-2 was ordered after the original OCO spacecraft failed to achieve orbit. During the first satellite's launch atop a Taurus-XL in February 2009, the payload fairing failed to separate from around the spacecraft and the rocket did not have sufficient power to enter orbit with its additional mass. Although a Taurus launch was initially contracted for the reflight, the launch contract was cancelled after the same malfunction occurred on the launch of the Glory satellite two years later.

United Launch Alliance launched OCO-2 using a Delta II rocket at the beginning of a 30-second launch window at 09:56 UTC (2:56 PDT) on 2 July 2014. Flying in the 7320-10C configuration, the rocket launched from Space Launch Complex 2W at Vandenberg Air Force Base. The initial launch attempt on 1 July at 09:56:44 UTC was scrubbed at 46 seconds on the countdown clock due to a faulty valve on the water suppression system, used to flow water on the launch pad to dampen the acoustic energy during launch. As of 2014, the mission is expected to cost US$467.7 million, including design, development, launch and operations. OCO-2 joined the A-train satellite constellation, becoming the sixth satellite in the group. Members of the A-train fly very close together in Sun-synchronous orbit, to make nearly simultaneous measurements of Earth. A particularly short launch window of 30 seconds was necessary to achieve a proper position in the train. As of 19 September 2016, it was in an orbit with a perigee of 701.10 km (435.64 mi), an apogee of 703.81 km (437.33 mi) and a 98.2° inclination. In 2025, the Trump administration requested NASA to formulate plans to terminate this mission.

Column CO2 measurements

OCO-2 is one of only two federal satellite missions that are designed specifically to monitor planet-warming greenhouse gases. Rather than directly measuring concentrations of carbon dioxide in the atmosphere, OCO-2 records how much of the sunlight reflected off the Earth is absorbed by CO2 molecules in an air column. OCO-2 makes measurements in three different spectral bands over four to eight different footprints of approximately 1.29 km × 2.25 km (0.80 mi × 1.40 mi) each. About 24 soundings are collected per second while in sunlight and over 10% of these are sufficiently cloud free for further analysis. One spectral band is used for column measurements of oxygen (A-band 0.765 microns), and two are used for column measurements of carbon dioxide (weak band 1.61 microns, strong band 2.06 microns). In the retrieval algorithm measurements from the three bands are combined to yield column-averaged dry-air mole fractions of carbon dioxide. Because these are dry-air mole fractions, these measurements do not change with water content or surface pressure. Because the molecular oxygen content of the atmosphere (i.e. excluding the oxygen in water vapour) is well known to be 20.95%, oxygen is used as a measure of the total dry air column. To ensure these measurements are traceable to the World Meteorological Organization, OCO-2 measurements are carefully compared with measurements by the Total Carbon Column Observing Network (TCCON).

Data products Mission data are provided to the public by the NASA Goddard Earth Science Data and Information Services Center (GES DISC). The Level 1B data product is the least processed and contains records for all collected soundings (about 74,000 soundings per orbit). The Level 2 product contains estimates of the column-averaged dry-air mole fractions of carbon dioxide, among other parameters such as surface albedo and aerosol content. The Level 3 product consists of global maps of carbon dioxide concentrations developed by OCO-2 scientists.

Illustrations

Worked examples

Example 1 — a first encounter with Orbiting Carbon Observatory 2

Start with the simplest possible case. Write down what Orbiting Carbon Observatory 2 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Orbiting Carbon Observatory 2 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Orbiting Carbon Observatory 2 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Orbiting Carbon Observatory 2

In research: Orbiting Carbon Observatory 2 appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Orbiting Carbon Observatory 2 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Orbiting Carbon Observatory 2 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2014 in the United States, Earth observation satellites of the United States, Greenhouse gases, so understanding it makes those chapters shorter.
In everyday life: Look for Orbiting Carbon Observatory 2 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Orbiting Carbon Observatory 2 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Orbiting Carbon Observatory 2 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Orbiting Carbon Observatory 2 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Orbiting Carbon Observatory 2 in simple terms?

Why does Orbiting Carbon Observatory 2 matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Orbiting Carbon Observatory 2?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Orbiting Carbon Observatory 2.