One of the world's most reliable space boosters ever built, suspended in a state of uncertainty for the past several months, won a rebirth today when NASA purchased three more Delta 2 rockets for future launches.

A Delta 2 rocket at Vandenberg. Credit: Justin Ray/Spaceflight Now See gantry rollback and sunset photos

The United Launch Alliance-made vehicle was dealt a bleak future when the U.S. Air Force left as the Delta 2's anchor tenant in 2009 and NASA flew what was its final planned payload on the medium-class launcher last October.

With no future missions on the manifest, it was possible that the workhorse rocket would fade away into history despite hardware available to build five more vehicles.

NASA's contracting arrangement established in 2010 didn't even include the Delta 2 as a option when buying rockets for science spacecraft deployments, but that changed with an "on-ramp" deal last fall that put the rocket back in the lineup for space agency satellites to chose.

Then came today's announcement that literally breathed new life into venerable rocket program, assigning three satellite launches to the Delta 2 that will occur from Vandenberg Air Force Base, California.

The launch trio and all of the assorted processing support, oversight, engineering and telemetry costs amount to $412 million.

"ULA is honored NASA has selected the Delta 2 launch vehicle to launch these critical science payloads," said Michael Gass, ULA president and CEO. "While we count success one mission at a time, we have been able to count on the Delta 2's success (96) times in a row over the last decade. This is a tribute to our dedicated ULA employees, our supplier teammates and our NASA Launch Services Program customer who ensure mission success is the focus of each and every launch."

First up is OCO 2, the replacement Orbiting Carbon Observatory built after the original spacecraft was lost in a Taurus XL launch failure in 2009. The satellite did not reach orbit when the rocket's nose cone failed to separate.

Artist's concepts of OCO 2, SMAP and JPSS 1. Credit: NASA

The new spacecraft is scheduled to fly aboard the Delta 2 rocket in July 2014, becoming NASA's initial environmental satellite dedicated to mapping atmospheric carbon dioxide and man's impact on Earth. The space agency had tapped Taurus for the reflight but later nixed that plan when the rocket failed a second time when the nose cone again didn't separate on the Glory satellite launch last year.

The Delta will insert the observatory into a 438-mile polar orbit to collect about 8 million measurements every 16 days to create maps showing global distribution of carbon dioxide.

Next will be SMAP, the Soil Moisture Active Passive satellite, set to launch in October 2014. Outfitted with a radiometer and synthetic aperture radar, the craft will orbit 423 miles above to Earth make global measurements of soil moisture to improve flood predictions and drought monitoring.

Then comes JPSS 1, the first civilian weather observatory in the Joint Polar Satellite System launching in November 2016. The craft will be operated by NOAA in a 512-mile-high orbit to take the planet's pulse daily for global forecasting, providing the ingredients needed for long-term weather outlooks.

It will follow the NPP spacecraft, which is expected to reach the end of its useful life around the time JPSS 1 is launched. NPP was carried on the most recent Delta 2 mission last October.

File image of a Delta 2 rocket launch from Vandenberg. Credit: William G. Hartenstein/Boeing

The Delta 2 rocket has flown 151 times since debuting on Valentine's Day 1989 and has a reliability rating of 98.7 percent. The track record includes only one outright failure and a remarkable string of 96 consecutive successful launches.

NASA has used the rocket on 50 launches to date.

In preparation for the upcoming missions, solid rocket booster-maker ATK will produce fresh motors to power those launches. ULA already has the other critical elements of the Delta 2s in stock.

The original backer of the Delta 2, spurring its creation in the 1980s, was the U.S. military, which successfully used the rocket for two decades to construct the Global Positioning System and sustain the orbiting constellation via dozens of launches.

But when the Pentagon steered its next-generation GPS satellites to the new Atlas 5 and Delta 4 vehicles, the Delta 2 lost its primary customer. Losing the Air Force and a diminishing mid-size satellite market were tough blows to the Delta 2's future.

While space agency and commercial satellite firms also used the rocket over the years, the Air Force had covered a large portion of the program's infrastructure costs. Delta 2 has since moved out of the Cape with no future payloads in the offing for flights from the Florida spaceport. Under current terms for Space Launch Complex 2 at Vandenberg, NASA will continue to oversee the pad while ULA maintains the site.

"The Delta 2 vehicle continues to offer excellent reliability and best value to our customers," said Gass. "We look forward to working with NASA for these future Delta 2 launch campaigns."

The two remaining unsold rockets will be kept available for potential additional launches to be added to Delta 2's flight schedule.

Also today, NASA announced the Jason 3 oceanography satellite to provide operational measurements of sea surface height for international organizations will be launched aboard a SpaceX Falcon 9 rocket in December 2014 from Vandenberg.

The cost of that launch is $82 million.