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“It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small.” – Neil Armstrong (1930-2012)

Fresh Reads from the Science 'o sphere!

Thursday, September 15, 2011

Space Launch System: The "Shutturn V" ?

NASA has announced their latest plan for a heavy launch vehicle - capable of manned missions into space - called the "Space Launch System (SLS)".

That isn't a particularly imaginative name.

YouTube commenter linghun dubbed it the "Shutturn V", which is actually quite appropriate, since the SLS is both technological and visually a hybrid of the Space Shuttle and Saturn V vehicles.

Here, check out NASA's video...

The SLS is a multistage, non-reusable vehicle that can launch both cargo-only and human-rated missions, much like the Saturn V.

The core stage uses an arrangement of five engines (Saturn V), which will consist of five RS-25 engines (Space Shuttle), while the upper stage uses a modernized version of the J-2 engine (Saturn V).

The first stage fuel tank will have the same diameter as the external tank of the Space Shuttle, and likely manufactured using similar methods. Two solid-fuel rocket boosters are attached, one on each side (Space Shuttle).

Visually, it either looks like a short Saturn V flanked with extra boosters, or a tall Space Shuttle external tank but without the Shuttle orbiter itself.

Appearances aside, expert observers seem to be unimpressed with the SLS programme and are already predicting its demise, calling it more of a job-creation exercise that may cost more than a completely new launch system, due to the re-hiring of the expensive legacy workforce.

To me, the SLS appears to have a much safer layout than the recently cancelled Ares I which perched human passengers on top of a solid-fuel first stage that cannot be throttled down or even shut down after ignition.

Of course the longevity of this new initiative is difficult to predict in this gloomy economic climate, and in light of less costly alternatives such as the SpaceX Falcon Heavy system, which is further along in development and has better scalability by using essentially the same engines and fuel tank components throughout.

Nevertheless, the SLS vehicle can initially lift 70 tonnes of payload into low-Earth orbit, up to a maximum of 129 tonnes in later configurations (more than Saturn V's 118 tonnes!). Even at 70 tonnes it would already be the heaviest lift launch vehicle in the world, compared to other launch systems currently in service.

Maximum lift capacity to LEO:
Delta IV-H (USA) ~ 23 tonnes
Proton M (Russia) ~ 21.6 tonnes
Ariane 5 (EU) ~ 21 tonnes
H-IIB (Japan) ~ 19 tonnes
Atlas V (USA) ~ 18.5 tonnes

If all goes according to plan, the first flight (unmanned) of the SLS is slated to be in December 2017.

Would you like to know more?
- NASA’s Space Launch System Unveiled: Analysis (Popular Mechanics)