Final Delta 2 launches a billion dollar ice probe

After thirty years of success as one of the most successful rockets in America, the 155th and last Delta 2 of United Launch Alliance came alive last Saturday and flew out of the California coast to measure the thickness and extent of polar ice caps, changes in sea level and the height of forest covers and clouds.

The ICESat-2 satellite – an acronym for Ice, Cloud and Land Elevation Satellite 2 – is the most advanced ice surveillance spacecraft ever launched, equipped with advanced electronics and a laser that will launch 10,000 pulses per second. second floor. then capture the weak reflections.

At the time of the departure and arrival of the photons to one billionth of a second, the satellite will be able to determine the thickness of the ice under the spacecraft, allowing scientists to understand how the ice sheets are changing with the time. Global warming and other factors could affect the sea level worldwide.

The mission will build on the results of an earlier, less powerful ICESat mission, and on a more limited NASA aircraft campaign, known as IceBridge, aimed at overseeing the ice inventory of the planet at decadal time scales.

"In half a second, it takes a person to blink, ICESat-2 will collect 5,000 measurements of altitude in each of its six beams," said Tom Neumann, Assistant Researcher for the ICESat-2 mission. "Every minute of every hour of every day for the next three years."

"And this incredible timing accuracy will allow us to measure elevation changes across the entire ice sheet to less than one centimeter," he said. "And this is important because a change of elevation of only one centimeter a huge amount of water, either gains or loss of the icecap – a value of 140 gigatonnes."

The Delta 2's main RS-27A engine came to life at 6:02 am local time (GMT-7, 9:02 am EDT), followed by the ignition of four solid fuel boosters.

The launch was delayed 16 minutes by a small technical problem, but the last moments of the countdown went well and the slender rocket quickly jumped from its firing point at Vandenberg Air Force Base in California. The first moments of the flight seemed normal as the vehicle accelerated towards the orbit.

The Delta 2 debuted in February 1989 with the launch of Cape Canaveral's first global positioning satellite. On Saturday's flight, the boosters recorded 154 launches with only one total failure in 1997, there are 100 flights.

"I'm a bit melancholy about this," NASA director Tim Dunn said Thursday. "Delta 2 occupies a very special place in the hearts of so many people.

The Delta 2 rockets have launched numerous satellite relay stations, seven Mars missions – including the Pathfinder, Spirit and Opportunity probes – Earth observation satellites, commercial payloads and scientific probes from the NASA, including the Kepler Space Telescope.

ICESat-2 was to be launched in a polar orbit of 300 miles approximately 52 minutes after launch.