On 14 September  2011, NASA revealed  the design of its new rocket, the Space Launch System. This titanic vehicle may send American astronauts to the Moon, Near Earth Asteroids or even further into deep space.

Image of SLS rocket

SLS: based on sheer awesomeness a contender for Best. Rocket. Ever (image credit:NASA)


The SLS is intended to carry NASA’s proposed new crewed spacecraft, the Multi-Purpose Crew Vehicle (MCPV, née Orion CEV) into space. Central to the SLS concept are two liquid-fuelled rocket stages. The first stage is 8.4m wide, exactly the same width as the Space Shuttle’s External Tank. Like the Shuttle two large solid fuel boosters are attached to the sides (in fact these are identical to the Shuttle’s SRBs, the idea is to save development costs by reusing as much Shuttle technology as is feasible) . Initially the first stage has three Space Shuttle Main Engines, but this will be increased to five  –  ensuring a truly awesome spectacle at launch.   (Scott Lowther at the Up-Ship blog has pointed that no new Space Shuttle Main Engines will be built for the SLS, it will use examples looted from museums!) The upper stage will use the J-2X, a modernised version of a rocket engine used in the classic Saturn series.

When introduced in 2017 (a date sure to slip), the SLS should be able to place 70 tonnes into Low Earth Orbit. It is planned to increase this to 130 tonnes eventually, making it the most powerful rocket ever built.

So what is this astonishing vehicle for? Bizarrely enough, the answer is no one knows. The SLS is  a solution looking for a problem. It is way too large to support the ISS and anyway the feeling in the US is that supplying the space station is trivial and tedious enough to be left to foreigners and the private enterprise johnnies.  If there was a program to return to the Moon, explore the asteroids or ultimately visit Mars the SLS would be very useful- but there are no such programs. True, there are vague and sketchy ideas for these adventures, but NASA has no budget to afford them and there is little sign that it will any time soon. To outside observers, development of the SLS is a Soviet Five Year Plan-style politically-mandated project aimed to prevent catastrophic job losses in areas where Shuttle components were made (I thoroughly approve of helping to save the jobs of people who actually make things, but is this the right way to do it?)

Don’t get me wrong, giant rockets are very cool and I want to see humanity expanding across the Solar System, but this seems an odd way to go about it. I hope history will prove me wrong (like if in 500 years time 14 September is celebrated across the Solar Federation as SLS Day).

Categories: Rockets


Dan · February 13, 2012 at 20:39

I wish it was so…man on the moon again is something that is a great goal, but eve if it is on schedule SLS heavy lift will not be ready until 2030..and we all know how government schedules work…. With JWST and SLS sucking the life out of the NASA budgets there is just no way this will work. They need to look at SpaceX Falcon etc. Cheaper and ready sooner. I am old enough that I saw two Saturn Vs take men to the moon. I had hoped that my children would be able to do the same someday. To understand the vision, to know what it is to dream and see that dream realized. Unfortunately with the leadership today, or rather the lack thereof, they may never see man on the moon. At some point we may have no living memory of that great event and how it unified us all, as stated from the moon … we “the people of the good Earth”.

David Jones · October 5, 2011 at 21:55

I don’t think this will be the first space program to be based on employment considerations. One of the factors that caused the Nixon administration to approve the Shuttle design in 1971 was that it was the version that generated the most jobs in California, a state Nixon needed to carry in the 1972 elections.

    admin · October 6, 2011 at 20:47

    Of course, you’re completely right. To the best of my understanding, what makes the SLS unique is the degree to which its design has been politically mandated compared to previous rockets.

Paul Evans · September 16, 2011 at 13:06

I think the key point is that it is a vehicle designed to keep NASA, and the US, in the game. With China and India pushing ahead with manned space programs, and Russia keeping its hand in with Soyuz, it was unthinkable that the US would abandon its activities completely at the end of the Shuttle Program.

I agree 2017 is way too optimistic – remember in the ’70s the Shuttle was supposed to ready to give Skylab a rejuvenation but didn’t launch until 2 years after Skylab had crashed into the Australian Outback. We can probably expect a similar delay, although this time hopefully the SLS will be ready in time to rejuvenate the ISS!


    admin · September 16, 2011 at 21:09

    Hi Paul, as a great spaceflight fan I’d love this to be the start of something big but the omens don’t look good. One thing I wasn’t aware of is that the SLS is to re-use Shuttle engines. There are not many of these left, 42 at most and when they’re gone, they’re gone. So there can only ever be 8-14 SLS launches!

    On the more positive side, even a couple of SLS launches could put up a really impressive space station!

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