Five years after their first spacecraft crashed into the ocean due a failed rocket launch, scientists are eagerly — and anxiously — awaiting the Orbiting Carbon Observatory-2 satellite’s liftoff from Vandenberg Air Force Base next month.

Liftoff of NASA’s Orbiting Carbon Observatory is planned for July 1 aboard a United Launch Alliance Delta 2 rocket from VAFB’s Space Launch Complex-2. The launch is planned for 2:56 a.m.

On Saturday morning, OCO-2 was to take a short road trip from the Astrotech Space Operations payload processing facility to SLC-2, where technicians were to hoist the spacecraft into place atop the Delta 2 rocket.

Once in orbit, the observatory will gather data about levels of carbon dioxide —from both human and natural sources — in Earth’s atmosphere to help scientists unravel the mysteries of the planet’s carbon cycle.

“OCO-2 will measure global concentrations of carbon dioxide and watch the Earth breathe as we measure the greenhouse gas that drives climate change,” said Betsy Edwards, OCO-2 program executive with the Science Mission Directorate at NASA headquarters in Washington.

Anxiety as launch day nears may be extra high for this mission.

Five years ago scientists eager for data about the greenhouse gas saw those dreams dashed when an Orbital Sciences Corp. Taurus rocket launch from Vandenberg ended in failure. The first mission cost $275 million.

NASA officials agreed to fund OCO-2 due to the misson’s importance to the scientific community, Edwards said.

Some of engineers and scientists from the first mission remained on the team for the second satellite, including Ralph Basilio, OCO-2 project manager with NASA’s Jet Propulsion Laboratory (JPL) in Pasadena.

“With the complete loss of the original OCO mission it was heartbreak,” Basilio said. “The entire mission was lost. We didn’t even have one problem to solve.

“On behalf of the entire team that worked on the original OCO mission we’re excited about this entire opportunity to finally be able to complete some unfinished business.”

With a mission cost of $465 million, OCO-2 has just one instrument — a spectrometer that will collect hundreds of thousands of measurements each day, providing an unprecedented level of coverage and resolution, Edwards said.

“Climate change is the challenge of our generation,” she said.

As a polar orbiting satellite some 438 miles high, OCO-2 will view locations on Earth at the same time of day every 16 days.

“We are eagerly anticipating the July 1 launch of OCO-2 so we can all watch the Earth breathe,” Edwards said.

The OCO-2 satellite, built by Orbital Sciences Corp., arrived at VAFB in April and has undergone preparation and tests. It also has received additional fuel to ensure the mission can operate beyond the planned two years.

OCO-2 will join 17 other Earth-observing satellites monitoring the planet’s vital signs, officials said.

The OCO-2 mission is one of five Earth science missions scheduled this year, NASA officials said.

Noozhawk North County editor Janene Scully can be reached at Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz.