Measuring Earth’s CO2 – and Solving a Mystery

The hexagon-shaped OCO-2 spacecraft was built by Orbital Sciences Corp. and weighs in at almost 1,000 pounds. Two 10-foot-long solar arrays will power all the observatory’s systems — including its only scientific payload. This instrument comprises three spectrometers that will break the sunlight reflected up from Earth’s surface into its component colors, then focus on the colors indicating carbon dioxide.

OCO-2’s spectrometer can also measure “chlorophyll florescence,” the energy given off by plants during photosynthesis. This means the spacecraft can see where plants are actively growing, and how that may interact with CO2 levels.

Scientists are hoping OCO-2’s discoveries will solve a mystery, too.

There’s a balance to the global carbon cycle. Plants and oceans are “sinks” — they absorb atmospheric carbon dioxide. But they can also release carbon dioxide back into the air. Human activities also create large quantities of CO2. In fact, since the start of the Industrial Age, we’ve introduced more and more CO2 to the atmosphere — on the order of 40 percent.

But some of this extra CO2 seems to have disappeared. Where is it being absorbed? Will this process continue? These are a few of the questions to which OCO-2 could provide answers.

Delta II an Industry Workhorse

The OCO-2 spacecraft will be delivered to orbit by a Delta II rocket – an industry workhorse with decades of success for NASA missions.

The two-stage vehicle stands 128 feet tall and measures eight feet in diameter, with a 10-foot payload fairing.

At T-0, the first-stage engine ignites along with the rocket’s three solid-rocket boosters. Its propellants are LOX, which is being loaded now, and a highly refined kerosene called RP-1, which was loaded previously. The second stage runs on hypergolic propellants that ignite on contact. Those propellants are already on board.

Liquid Oxygen Tanking Up Next

The next major countdown milestone is the loading of liquid oxygen, or LOX, into the rocket’s first stage. LOX is chilled to a very cold minus-297 degrees, making it a cryogenic propellant. NASA Launch Manager Tim Dunn polled his team and received the “go” to start this process a few minutes from now. ULA Launch Conductor Ward Johansen will check in with his team members momentarily to verify they’re ready to begin.

Weather Update

rocketfull2Weather and wind conditions at Vandenberg will not pose a problem for the launch team this morning.

The marine layer that brings fog to the coast is creeping into the area, but skies are clear above. Visibility at launch time is predicted to be 1 to 2 statute miles and winds will be light at 4 to 7 knots. There are no watches, warnings or advisories in effect, and weather is “green” on all constraints.

Live Launch Coverage Begins

Good morning, and thanks for joining us for the countdown today. NASA’s Orbiting Carbon Observatory-2 is sealed at the top of a United Launch Alliance Delta II rocket at Vandenberg Air Force Base, aiming for liftoff from Space Launch Complex 2 at 2:56 a.m. PDT, 5:56 a.m. EDT. Today’s launch window extends for 30 seconds.

This is the second launch attempt for OCO-2. During the first attempt yesterday morning, the countdown was halted 46 seconds prior to liftoff when a valve that is part of the pulse suppression water system failed to function properly. The failed valve has been replaced and tested, and the team is ready to try again. Weather is 100 percent favorable for liftoff this morning.

The OCO-2 spacecraft will spend two years circling Earth in a polar orbit. From its vantage point more than 430 miles above Earth’s surface, the observatory will provide the first-ever global survey of atmospheric carbon dioxide, or CO-2. With OCO-2, scientists hope to learn more about the balancing act involved in the global carbon cycle — the give-and-take between the sources of CO2 and the areas that absorb it, called “sinks.”

OCO-2 Launch Set For Wednesday Morning

Orbiting Carbon Observatory-2 (OCO-2)
OCO-2 at the launch pad. Credit: NASA/Bill Ingalls

The launch of NASA’s Orbiting Carbon Observatory-2 (OCO-2) aboard a United Launch Alliance Delta II rocket is scheduled for Wednesday, July 2 at 5:56 a.m. EDT (2:56 a.m. PDT) from Space Launch Complex 2 at Vandenberg Air Force Base in California.

The launch team has completed troubleshooting of the launch pad water suppression system that resulted in the scrub of the launch attempt Tuesday. A valve that is part of the pulse suppression water system, which had operated properly during tests shortly before the launch countdown, failed to function properly during the final minutes of the launch attempt. The failed valve has been replaced with a spare, and the system is being tested in preparation for Wednesday’s launch attempt.

The OCO-2 mission will produce the most detailed picture to date of natural sources of carbon dioxide, as well as their “sinks” — places on Earth’s surface where carbon dioxide is removed from the atmosphere. The observatory will study how these sources and sinks are distributed around the globe and how they change over time.

The launch weather forecast is unchanged with a 100 percent chance of favorable conditions at liftoff, which is targeted for 5:56:23 EDT (2:56:23 PDT) at the opening of a 30-second launch window.

NASA Television coverage will begin at 3:45 a.m. EDT (12:45 a.m. PDT) Wednesday.