The latest Delta II rocket launches the NASA satellite to map the Earth's ice with the space laser

A $ 1 billion NASA mission, which will use a laser to track the evolution of ice levels on Earth, flew Saturday (Sept. 15) into a California sky before dawn from a mission.

NASA's Ice, Cloud and Land Elevation-2, or ICESat-2, took off from Space Launch Complex-2 at 09:02 EDT (6:02 PDT or 1302 GMT) at Vandenberg Air Force Base in Southern California. The launch marked the 100th unprecedented flight of the United Launch Alliance (ULA) Delta II rocket that, over the last 30 years, has projected the first GPS satellites, deployed commercial telecommunications constellations and sent robotic probes . the moon, Mars and asteroids.

"This has been a very important part of the history of space," said Scott Messer, head of NASA's program program at ULA, during a pre-launch press conference on Wednesday 13 September. . [In Photos: NASA’s ICESat-2 Soars on Last Delta II Rocket]

For its 155th and last mission, the Delta II flew in its 7420-10 configuration, equipped with four epoxy graphite engine (GEM) side boosters, which were dropped 1 minute and 22 seconds into the flight and 10 feet. diameter (3 meters) load fairing, which was eliminated in the same way about 4 minutes later, when the rocket climbed into space. The Delta II second-stage engine performed the first of four burns scheduled 11 minutes after take-off, placing it in an initial elliptical transfer orbit.

If all goes as planned, the Delta II's second-stage AJ10-118K engine will reignite for 6 seconds at 47 minutes before deploying ICESat-2 into orbit. Twenty-three minutes later, the stage will start again to trigger the release of four small satellites.

The tiny CubeSats were designed and built by UCLA, the University of Central Florida and Cal Poly to conduct space weather research, change the electrical potential and landfills on spacecraft and the behavior of tungsten powder in an environment without gravity.

The final telemetry of the Delta II story is scheduled about two hours after launch, sometime before the second leg that will impact the South Pacific Ocean.

Meanwhile, the ICESat-2 mission begins.

"About an hour after our launch, the spacecraft separates from the launcher and, within 30 minutes, the solar panels are deployed," said Doug McLennan, ICESat-2 Project Manager at the Goddard Space Flight Center. NASA.

The ICESat-2 spacecraft serves as a power and pointing platform for the mission's unique instrument, the advanced laser altimetry system, or ATLAS.

"We're not going to turn on ATLAS for about a week and we're just checking it in. We do not open the [telescope] door for about another week. And then we start collecting the first ATLAS data, activating the lasers and starting our commissioning process, "said McLennan, adding that the commissioning period will last about 60 days.

Once the science mission begins in earnest, ATLAS will begin directing 10,000 green light pulses per second to Earth to record the time needed to rebound some of these photons. Transit time can be used to calculate ultra-precise altitude measurements from space, providing researchers with a map of changes in ice levels and tree growth.

"We are going to have measurements everywhere and we are going to have a much higher resolution, so we can do a better job by linking the change [in ice levels and forest growth] to climate in general, "said Tom Wagner, scientist of the ICESat-2 program at NASA's headquarters in Washington, DC.

Robert Pearlman is editor and editor of collectSPACE.com, a Space.com partner site and the leading news publication on the history of space. Follow collectSPACE on Facebook and Twitter @CollectSpace. follow us @ Spacedotcom, Facebook and Google+. Original article on Space.com.