Jason DavisSep 15, 2011

NASA unveils Space Launch System

Human spaceflight fans have a new computer desktop wallpaper.

NASA has officially revealed the design of the much-anticipated Space Launch System, the next "exploration-class" human spaceflight vehicle for missions beyond Earth orbit. Outfitted in a pearly white paint scheme with black pinstripes, digital renderings of the SLS evoke memories of the Saturn V rockets that took humans to the moon four decades ago. Strapped to the sides of the massive core vehicle are two familiar-looking solid rockets, big brothers of the same boosters that sent space shuttles into low-Earth orbit for thirty years. Perched high atop the rocket is the Orion Multi-Purpose Crew Vehicle, ready to house four astronauts during proposed missions to a near-Earth asteroid and Mars.

Unveiling the rocket in Washington was NASA Administrator Charles Bolden, flanked by congressional SLS supporters Kay Hutchinson (R-TX) and Bill Nelson (R-FL). The announcement ends months of political wrangling over the design and cost assessment of the rocket, which culminated last week in accusations of a 'campaign to undermine America's manned space program' being hurled at the Obama Administration.

What's under the hood? The Space Launch System

The core component of the SLS is a massive, two-stage, liquid-fueled rocket (liquid hydrogen and oxygen). Stage one, which would fire during liftoff, would be powered by five RS-25D/E engines – the very same ones used in groups of three as the space shuttle orbiter main engines. The SLS concept looks gorgeous in its white Saturn V livery, but it remains to be seen if it will stay painted that way; earlier SLS concepts showed a brown fuel tank section that looked very much like the space shuttle's external fuel tank. Remember the first flights of space shuttle Columbia, which used white fuel tanks? That color scheme turned out to be an unnecessary protection against ultraviolet sunlight while the shuttle sat on the launch pad, and they eventually did without the paint to save weight.

Stage two of the rocket, which would kick in after the first stage burned out and separated, is another Saturn throwback: a single J-2X engine, presumably capable of shutting down and restarting like the original Apollo-era J-2 engines. This trick enables flights out of Earth orbit to take an unpowered lap around the Earth before firing the engine again to head for deep space.

The new Orion Multi-Purpose Crew Vehicle can hold four astronauts, making it a little roomier than its Apollo predecessors. Unlike the SLS core, Orion is already under construction, and has been through dips in the pool at NASA Langley's splash test basin, and a barrage of sound vibration tests. Also already in testing are the solid rocket boosters (SRBs), which will initially be constructed by Alliant Teksystems, the same contractor for the space shuttle SRBs. As the SLS design evolves over time, the booster designs will be re-examined, opened to competitive bidding, and possibly replaced with liquid-fuel variants.

Speaking of evolving, the SLS would grow in power and capacity over time, just as the Saturn rocket system did, as NASA gains experience and builds up to more ambitious missions. The initial SLS configuration, which is proposed to fly without humans in 2017, would be capable of carrying 70 metric tons into orbit. The final, "evolved" design would be able to handle 130 metric tons, the same amount as the Saturn V. Space.com has a great infographic that compares the SLS to other famous space vehicles.

If you're ready to experience your first SLS liftoff, crank up your speakers and watch the animation below. There's great attention to detail, all the way down to a delay between the ignition of the liquid and solid engines. As with the space shuttle launches, it looks like the SLS will need to pause while the liquid fuel engines ramp up to full thrust before committing to launch by igniting the solid rocket boosters. All that's missing in the video is the voice of NASA public affairs officer George Diller, excitedly proclaiming that the SLS has cleared the tower.


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