ICESat-2

The Delta II rocket’s second stage engine has completed its first burn. The rocket and ICESat-2 spacecraft are entering a 36-minute coast phase.

The Delta II rocket’s first stage engine completed its burn on time and separated from the vehicle. The second stage engine is burning now. The payload fairing separated on schedule, exposing the ICESat-2 satellite to the space environment for the first time.

Ignition and liftoff! NASA’s ICESat-2 spacecraft is on its way into orbit to embark on a three-year mission to measure the changing height of Earth’s ice. The United Launch Alliance Delta II rocket is making its final climb into space after an early morning launch from Space Launch Complex-2 at Vandenberg Air Force Base in California.

The rocket’s four solid rocket boosters will be jettisoned one minute, 22 seconds into the flight. Main engine cutoff follows about three minutes later, then separation of the first and second stages. This separation clears the way for the second stage engine to ignite at 4 minutes, 37 seconds into the flight.

The United Launch Alliance team is “go” for launch. The ICESat-2 spacecraft is configured for launch and has been transferred from ground to battery power.

Countdown clocks are counting down from the T-minus 4 minute mark.

NASA Launch Manager Tim Dunn just conducted his team’s final launch readiness poll and all are “go” for launch.

“The NASA team is ‘go’ for the ICESat-2 mission on the Delta II,” Dunn said.

The launch team is working toward a new launch time of 6:02 a.m. PDT (9:02 a.m. EDT). The T-minus 4 minute hold has been extended to accommodate the new time.

Countdown clocks have paused for 10 minutes at the T-minus 4 minute mark. This is the final planned hold in today’s countdown.

The ICESat-2 spacecraft and ELaNa XVIII payload will be carried into space aboard the United Launch Alliance Delta II rocket. In use since 1989, the Delta II has a stellar track record: it’s launched 154 times, carrying payloads aloft for NASA, the U.S. military and commercial clients. Today’s launch will be NASA’s 54th on the Delta II; some of the agency’s many flights aboard the Delta II include the Mars rovers, Spirit and Opportunity; Earth-observing satellites such as Joint Polar Satellite System-1, Aquarius and Suomi NPP; and missions exploring our solar system and beyond, including GRAIL, Dawn and Kepler.

The two-stage Delta II awaiting liftoff this morning at Space Launch Complex-2 stands 132 feet tall. It has four side-mounted solid rocket motors attached to its first stage and is topped by a 10-foot-diameter payload fairing. The first stage’s RS-27A main engine is powered by liquid oxygen and RP-1, a rocket-grade kerosene. The second stage’s AJ10-118K engine is powered by hypergolic propellants Aerozine 50 and nitrogen tetroxide.

Launch Weather Officer 1st Lt. Daniel Smith of the 30th Space Wing just briefed the team on today’s weather forecast, and it was good news: The forecast remains 100 percent “go” on all constraints.

Countdown clocks are now at 15 minutes and counting.