Three stages of separation: bidding farewell to the Delta II launch vehicle
The United Launch Alliance Delta II rocket that will launch NASA’s Ice, Cloud and land Elevation Satellite-2 sits vertical on the launch pad at Space Launch Complex-2 at Vandenberg Air Force Base. (Image source: Chris Giersch, NASA EDGE Langley)
 

Three stages of separation: bidding farewell to the Delta II launch vehicle

Tomorrow’s planned ICESat-2 launch will be the space industry workhorse’s final flight.
The upcoming launch of the NASA Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will be the last liftoff for the Delta II rocket, whose reliability made it a mainstay for civil, military, and commercial space customers. The medium-lift Delta II is manufactured by Centennial, Colo.-based United Launch Alliance (ULA), a joint venture between Lockheed Martin Space Systems and Boeing Defense, Space & Security, and features main and upper-stage engines supplied by Aerojet Rocketdyne of Sacramento, Calif.

ULA’s Delta II rocket has provided dependable access to space for nearly 30 years, launching 154 times since its debut on Feb. 14, 1989. The launch vehicle’s legacy is one of lasting stuff, including launching Earth’s modern global positioning system (GPS) navigation satellites into orbit – you know, the ones we use every day – to deliver NASA’s expensive remote-controlled cars, Spirit and Opportunity, safely to the surface of Mars.

Now get ready: I’m about to throw a lot of big numbers around.

Stacked 132 feet, and weighing 358,000 pounds, the Delta II’s elements are already assembled in the launch mount. It will launch in a 7420-10C configuration with an Aerojet Rocketdyne RS-27A liquid-oxygen and kerosene-fueled first stage and four side-mounted solid rocket boosters all igniting for 650,000 pounds of thrust at liftoff.

The second stage is an Aerojet Rocketdyne AJ10-118K hypergolic engine running on nitrogen tetroxide and Aerozine 50 - a 50-50 mix of hydrazine and unsymmetrical dimethylhydrazine. The second stage engine generates 9,850 pounds of thrust at altitude.



While 130 feet might seem high, this time tomorrow, the ICESat-2 will be staring down from low Earth orbit at 308 miles. (Image source: Chris Giersch, NASA EDGE Langley)
 

Both the RS-27 and AJ10 engines have powered the rocket’s first and second stages with 100 percent reliability, with 241 and 277 flights each, respectively. Since ICESat-2 will be placed in a low Earth orbit, there is no need for a solid propellant third stage.



(Image source: ULA)
 

The ICESat-2 payload – built by Northrop Grumman of Falls Church, Va. – will be protected during atmospheric ascent by a 10-foot-diameter composite payload fairing. ICESat-2 has a single instrument, the Advanced Topographic Laser Altimeter System (ATLAS), and will provide scientists with height measurements to gather data that can precisely track changes of terrain, including glaciers, sea ice, forests, and more.

The launch is planned for Saturday, Sept. 15, 2018 at 5:46 a.m. PDT from Space Launch Complex-2, Vandenberg Air Force Base, California (the Delta II’s West Coast stomping grounds). Live coverage of the launch will begin at 5:10 a.m. PDT.



And if you can’t get to it then, check out this highlight reel from the Delta II Joint Polar Satellite System launch from November 18, 2017.



"The Delta II will go down in history as one of the world's most successful launch vehicles, and we're proud to be part of that legacy," says Eileen Drake, Aerojet Rocketdyne's CEO and president.

Although the ICESat-2 launch will likely be the evolutionary end of the RS-27A, the AJ10 engine family will continue to fly as part of NASA's Orion spacecraft program. The main engine on Orion's European-built service module is derived from the Space Shuttle's orbital maneuvering system engine, which shares a common heritage with the AJ10-118K.

In the end, as a going away party, it’ll be less “all-night revelry” and more “tasteful night out with close friends.”

If the Delta II could talk, and in my head it can, it would have the voice of Kevin Bacon:
 
“I think of myself more as a workhorse actor. It will be hot and cold and up and down, but no one will kick me out of the business.” – Kevin Bacon
 

<<This Friday post is part of our “Composite coverage: real lightweight stuff” series and a departure from SAE International’s traditional reporting approach. Let us know if you like our fun, conversational, and most likely irreverent coverage of legitimate news and notable events.>>
 

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William Kucinski is content editor at SAE International, Aerospace Products Group in Warrendale, Pa. Previously, he worked as a writer at the NASA Safety Center in Cleveland, Ohio and was responsible for writing the agency’s System Failure Case Studies. His interests include 'literally anything that has to do with space,' past and present military aircraft, and propulsion technology. And also sportscars.
 
Contact him regarding any article or collaboration ideas by e-mail at william.kucinski@sae.org.
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