Does SLS Have a Future?

SLS takes off from the launch pad. Image credit: NASA

At first look, NASA’s Space Launch System (SLS) looks like the perfect rocket: heavy lifting launch vehicle that promises to be more versatile, powerful, and durable than anything that has preceded it. But there are major threats hanging over the rocket stacking the odds against it ever leaving the ground.

By design, SLS is pretty incredible. It’s central piece is a liquid fuelled core stage modelled off the space shuttle’s external tank. The core stage is flanked by two boosters that will enable early Block 1 and Block 1A versions of the rocket to lift 70 metric tons into Earth orbit. A small “kick” stage will give payloads on these smaller rockets the extra push for distant targets like the Moon. The later “evolved” SLS will feature a second stage that will facilitate lifting 130 metric tons into orbit. All three versions will be adaptable for manned spacecraft or cargo depending on the mission’s needs. As a point of reference, the evolved SLS will be as powerful as the Saturn V and less than 50 feet taller.

For all its flexibility, SLS seems like it was built with strange design choices in mind. The core stage won’t be recovered or reused after launch. The Block 1 version will use four reusable RS25-D engines leftover from the shuttle program, but when NASA’s stock of these old engines runs out it will switch to the larger and more powerful RS25-E engines – the E stands for expendable. The Block 1 boosters will also be modelled off shuttle technology, burning through solid fuel and recovered from the ocean for refurbishment after launch. The slightly larger Block 1A will introduce new boosters, possibly liquid fuelled depending on who builds them, that will not be recovered and reused. Block 2’s upper stage will add another expendable stage to the evolved rocket.

This illustration shows the SLS in comparison to other rockets in NASA's launch arsenal as well as some built by private companies. Image credit: NASA

So after its first few Block 1 launches, NASA will have a single-use rocket on its hands. This was a major problem towards the end of the Apollo program. Saturn Vs were expensive to produce and launch, especially since each could only go up once. Post Apollo plans that relied on the Saturn V’s lift capacity were scrapped and reusability as a cost-saving measure was a main factor in the shuttle’s design.

Like the Saturn V, the cost associated with SLS launches could prove prohibitive. Early estimates suggest that each launch could cost between $8,500 and $10,000 to deliver just one pound with SLS. For the Block 1 and 1A to launch the maximum 70 ton payload, that’s $1.3 billion per launch; the Block 2 will cost about $2.45 billion per 130 ton payload. As a reference point, each shuttle launch cost roughly $1.5 billion, and each Saturn V around $1.17 billion (adjusted to 2012 dollars). If these SLS launch estimates prove true, it’s hard to see how the space agency will sustain the rocket. Critics are slamming SLS for its high cost. In addition to launch costs, SLS is expected to cost $10 billion in development leading up to the first launch.

With such high launch costs, every one has to count. But SLS doesn’t have clear goals for the new rocket. The first SLS-launched mission, scheduled for December 17, 2017, will see a Block 1 send an unmanned Orion spacecraft on a free return trajectory around the Moon. The next launch sometime in 2019 will see a crew make the same flight. After that, tentative plans call for one launch each year. Destinations include the Moon and near Earth asteroids. Once the Block 2 makes its appearance sometime in the 2030s, we will see missions sent to Mars.

Full view of SLS sitting on the launch pad. Image credit: NASA

2030 is a long way away, and for SLS to last that long it will need funding. Funding, in this case, from Congress. Orion and SLS are the two surviving pieces of the Constellation program started under President Bush Jr. and cancelled by President Obama. After sparing SLS, members of Congress began making demands on and setting parameters for the rocket going so far as to specify contractors. Individuals are working hard to secure contracts for companies in their home state, creating jobs and winning the support of voters. The heavy hand of self-interested lawmakers has led some critics to call SLS a job-retention program disguised as a rocket and landed SLS the unfortunate nickname of “Senate Launch System.

To make matters worse, despite its scheduled launch dates SLS still lacks support. And with another election around the corner, it’s nearly impossible to predict what will happen in the next few years. With the right space-supporting people in positions of power, it may come to fruition? But if SLS’ critics make up the majority it will be a different situation. Unfortunately, without concrete goals that the public can really understand and get excited about, it’s likely votes will go to those state representatives hoping to kill the SLS program before it gets too far.

It’s an unfortunate “wait and see” situation. The worst case scenario is to see SLS scrapped, the research from its early development and planning is applied to another program while the documents written in the electronic age become a goldmine for future space historians. The best case scenario would be for NASA to establish and commit to concrete goals for the a program that sees SLS through its development, giving us a means to explore and unravel more mysteries of our solar system.

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  1. It’s nice to see these numbers written up in a simple-to-understand way. We are truly at a turning point in our national space program. We now have two options: to move ahead and make bold leaps back into space, or continue our present path and step back and abandon our space effort. I surely hope our “leaders” do not lead us away from the space frontier but I am fearful that we are already well down that path. I hope I am proven wrong.

  2. This is a good analytical look at SLS. I also wonder what will happen when the proposal for the advanced booster is decided on. Thr 130 ton “upgrade” will be expensive, much more so if they choose a new contractor and have to start from scratch. I think there is a good chance we will continue to go for more launches with the current baseline design. This would reduce costs while allowing NASA continued access to deep space. I think the reality of starting over will be a hard pill to swallow. I definitely agree tha the worst choice would be to cancel SLS. We would wallow in space mediocrity while more commissions decide that any course is unsustainable.

  3. You didn’t mention the biggest threat to SLS – sequestration.

    And Senate Launch System was earned fair and square.

  4. I am hoping, that if there is a change of leadership in November, that the new administration will realize that this is America’s launcher, not Obama’s. The problem with our space program is what Scott Adams called the ‘bungee boss’ problem, where a new boss will come in quickly, change everything, then leave quickly, leaving chaos.

    • The Big/Dumb heavy lift rocket built to ship-building standards has been out there for 35+ years, and we’ve never made a single one. In the meantime, Russia still uses a variant of the Sapwood rocket from 1957, and has more launches than we could hope to have.

      There surely must be a happy median… priorities for humans in deep space are null. A purpose for going back to the moon is only necessary to prevent China from bringing back our flags!!! Come up with a 10 mission or 5 mission plan for the moon, STOP THROWING AWAY A $TRILLION ON USELESS WAR, and we can fund NSA, the NRO and development without a $$ ceiling!

      If for no other reason than heavy, unmanned lift capacity, the Sea Dragon is a “Here/NOW” engineering project that could bridge other technologies. The integrated complexities that the USA tends to combine into everything for the most advanced systems, when the simplest, lower cost, RELIABLE systems are what can keep us from being STRANDED, have been ignored for, in the case of the SD/Big-Dumb Rocket… FIFTY YEARS, THIS YEAR.

      As for this “Obama Rocket” – stop politicizing the fact that GOP threw all the $ away in Asia as if it is Obama’s fault. NIXON had to cancel Apollo 18, 19 & 20 in order to wage war, produce a Space Shuttle, fight the Cold War and put in place even MORE social spending than LBJ did via the Great Society programs.

      I don’t recall any attributions to the Saturn V’s on display as “Nixon’s Failures” nor Challenger being referred to as “Reagan’s Leadership Failure” – when some may have been justified.

      I suggest everyone read Phil Tompkins’ book on NASA from 1958 to 2003 — a former professor of mine who literally created the field of Organizational Communication, and for Von Braun, CREATED the hierarchy at NASA and the vendor relationships (and leader/power structure) that achieved the objectives, but were completely lost by Challenger as well as with the original Hubble project.

      Too much commentary/opinion, without enough FACT nor EXPERTISE. You waste our time in reading your drivel.

      NASA’s former director of astrophysics, Charlie Pellerin, has learned a thing about leadership and project failure… —>

      Tompkins —>
      I was so fortunate to be a student of his 30 years ago.

      * 1967: when Tompkins first served as a Summer Faculty Consultant in Organizational Communication to legendary rocket scientist Wernher von Braun during the Apollo Program.

      * 1968: when he served in the same capacity to help reorganize NASA’s Marshall Space Flight Center.
      * 1986: when he investigated the communication failures that caused the explosion of the space shuttle Challenger.
      * 1987: when he researched NASA’s highly successful Aviation Safety Reporting System.
      * 2003: when he interpreted the communication failures leading up to the catastrophic failure of the space shuttle Columbia.

  5. Is it too fanciful to hope that a rocket with a 70t might be intended to carry, first, the material to build an orbital platform and then a carbon nanotube strand to drop from it?

    That is, was SLS preserved specifically by Obama because it is – and always was – an essential step in the construction of a space elevator? Perhaps it was never intended to see much re-use.

  6. After some interesting comments about this article on Twitter, I’d like to add launch readiness and recovery to the overall SLS cost. NASA will have to spend money to make sure SLS is ready to go, which means employing the launch support personnel, and splashdown recoveries will certainly add another expense.

  7. Beer bet it never flies. Don’t get me wrong – I’d love to be proven wrong on that, it’s the only NASA built rocket we’re going to get (if any). SpaceX, Orbital, ATK, and ULA (Atlas and Delta IV) all will be flying next year – that’s a very good thing (OK – ATK’s a maybe). There are 6 crew vehicles in development, also a good thing. Bigelow will be flying a space station in about 3 years – a VERY good thing. Not to mention all the sub-orbital stuff in the pipeline (Masten, Armadillo, XCor, Blue Origin).

    If you want a heavy lift rocket, build the biggest and simplest rocket ever designed – SeaDragon. Makes this thing look like a botch job Estes rocket. Cost to design in 2012 dollars? $5B. Cost to launch: $300M. Lbs to LEO? 1,200,000 – that’s right 550 TONS. Price/lbs? do the math: <$300/lbs

    Follow me on Twitter @VAXHeadroom

    • Good old Vax. Never, ever going to give up on the Sea Dragon are you? (And don’t even try to get me to argue with you on here. I’ve lost enough times to you already.)

  8. I think something with the lifting capacity of the SLS is necessary, and since there is no commercial market for loads of that size, it logically falls to a government program to fund it. That said, I’m concerned that funding for the SLS is crowding out the rest of NASA’s missions. Planetary science has already been all but gutted, and CCDev is now under immense pressure from the Senate committee members (Who of course represent the states that benefit the most from the SLS).

    The number of missions where you need an SLS-sized launcher is currently very small, however. Since it will be unquestionably more expensive to launch SLS than existing EELVs, it would only make sense to use SLS in a couple situations: A payload that can’t fit within EELV fairings (currently around 5 meters) or a payload that can’t cost-effectively be split up into pieces and reassembled in orbit. This will rarely be the case for most of the weight involved in even our most ambitious existing manned spaceflight plans. Fuel and provisions can go up in multiple trips, and service modules can go up and be joined to crew modules in orbit.

  9. The true “best case” scenario would be if NASA stops spending so much money just trying to get crewed vehicles to orbit that there’s no budget left to do much of anything worthwhile when they get there. I don’t see how SLS gets us on that path.

    The Aldridge Commission was clear that the only way NASA could affordably explore space was to use existing launchers and commercial services so it could focus its limited human space flight budget on missions and the systems to directly support those missions.

    We in the spaceflight community continue to ignore those recommendations and the need to articulate a clear, relevant, and compelling vision for human space exploration at our own peril.

  10. My article:
    The SLS: too expensive for exploration?
    by John Strickland
    Monday, November 28, 2011

    covers some of the same issues but I come to a very different conclusion. Agreeing on a goal will not solve the problem, since there are few if any space goals that we could afford to access via the SLS. We will not be able to even afford to launch the SLS more than about once a year. With private, reusable rockets, NASA could afford to explore the Moon AND Mars AND asteroids all with the same program.

    Now another famous voice has spoken out against the SLS:

    Space Launch System is a threat to JSC, Texas jobs
    By Chris Kraft and Tom Moser
    Updated 08:20 p.m., Friday, April 20, 2012

    The Congress will not listen to these voices – the issues are all local jobs for the moment (to get re-elected for the current term).

  11. I don’t think the problem is the cost of the program.

    I think the problems are that: 1) the current administration has set forth vague and, quite frankly, rather unexciting goals that the SLS system does not clearly match up with; 2) these goals have been put to a timetable that runs so far into the future that it is both unlikely to be done because of political changes and because no one but the most die-hard space geeks are excited about it; and 3) there is no clear movement going on aside from a few people like the wonderful Neil DeGrasse Tyson that aims to educate people on the benefits and wonders of manned space flight.

    This is a mistake, however. While private companies are filling in the earth-orbit gap left by the shuttle, there will be no attempts at manned spaceflight beyond earth orbit by the private market for some time to come. NASAs mission should be to work with these private companies to create a flourishing private market in earth orbit while taking over heavy lifting duties as well as returning to the Moon and pushing out to Mars and beyond. We need a system like SLS to do that.

  12. The problem with quoting numbers occurs when you don’t put those numbers in context. Reading that SLS costs $8,500 to $10,000 per kg to put a payload in orbit sounds high. Until, that is, context is added by including the costs of other systems.

    Launch costs for SLS need to be compared to those of Shuttle and launch costs expected under the CRS, or Cargo Resupply Services contract, which follows COTS-D’s completion. CRS funds at a cost of $3.5 billion the delivery of 40 mT to ISS between 2010 and 2015. Already one can see that the launch costs expected under CRS will be substantially higher than with SLS Block 1, which is expected to cost $1.3 billion per launch for 70 mT, or 37% of the CRS for 75% more cargo.

    CRS contracts were awarded to SpaceX and Orbital Sciences. SpaceX was awarded $1.9 billion to launch 20 mT over 12 flights. Orbital Sciences was awarded $1.6 billion to launch 20 mT over 9 flights. It is noticeable that each of these companies was awarded substantially more money than the average expected cost of an SLS Block 1 flight to deliver a mere fraction of the SLS’s payload capacity.

    The only real numbers for estimated CRS launch costs on a per kg. basis comes from the House Subcommittee On Space And Aeronautics’ charter for its May 26, 2011 hearing, aptly titled, NASA’s Commercial Cargo Providers; Are They Ready to Supply the Space Station in the Post-Shuttle Era?. Turning to page 5, one notes a table at the bottom. Launch costs are as follows:

    Space Shuttle – $9,647/kg
    Soyuz – $8,232/kg
    CRS – $12,143/kg (18,001/kg if valued as Shuttle’s costs are)

    I’ll let you digest those numbers for a second.

    It should become clear from reading those costs that SLS Block 1 and Block 2 represent not a significant increase in launch costs compared to previous, existing, and soon-to-be-commercial launch solutions. Instead, SLS represents at its worst case parity.

    This might explain why support within Congress for the Space Launch System is both bipartisan and steady. Members, or at least their staffers, are seeing launch cost estimates that price every existing and near-future launch system more or less out of the market in the task of delivering cargo for beyond Earth exploration missions. Another reason for SLS support in Congress could very well be that there exists no other system that can place payloads such as new modules, arrays, or other over-sized cargo. As ISS ages, SLS will take the place of Shuttle in keep the station operational.

    Indeed, at $8,232/kg to $12,143/kg people are correct when stating that we cannot today afford to explore beyond the near region of Earth orbit. Beyond Earth exploration only becomes affordable with the Space Launch System’s lower costs and higher cargo capacity.

    The real question is not whether SLS will survive. The above numbers, even if off significantly, show clearly that SLS will not only survive but will allow us to once again afford to explore the heavens. The real question is whether SpaceX, OSC, and any other commercial launcher will be able to survive with significantly higher launch costs relative to SLS except in the small payload market. How ironic if these commercial efforts require a protected niche market in order to survive competition from SLS.

    • That whole charter proved to be filled with inaccuracies, which were expanded upon during the hearing. For example, one point which is not included in the discussion is density of the payload. The CRS numbers used were actual costs, irregardless of density, but shuttle assumes a very dense payload

  13. Ferris,

    If you are referring to the optimized loading of the payload, that would be a valid comment except that it has little to do with launch cost calculations on a general level. Of course, if you can pack more cargo more efficiently into a launch, you maximize your economics of that launch. However, the maximum cargo lifting capacity of a launcher cannot be exceeded. Simply put, if your payload limit for 28° LEO is, as an example, 10 mT, no amount of optimized loading will allow you to exceed, although it will certainly help you achieve for a given volume, that mass limitation.

    If there is fault with the analysis contained in the May 26, 2011 CSJ House Space Subcommittee charter, perhaps you will be good enough to link to the corrected analysis?

    If we do not measure launch costs with “actual cost”, then which “cost” do you recommend using?

    As the House charter, to which I referred, notes, NASA shouldered if not the full, then certainly the substantial majority of, development cost of both OSC’s and SpaceX launchers that will be used in performance of their CRS contacts. By not having to amortize DDT&E (design, development, testing, and evaluation) costs of their launchers, the CRS contractors already have their launch costs lowered significantly and artificially. Built-into initial Shuttle launch costs were the amortized cost of Shuttle DDT&E. The same will be true for SLS. So in this light, we can see that the cost case for CRS contractors is even higher than the numbers indicate.

    There is another way in which CRS payload costs are biased in a favorable manner. The House numbers do not initially include the cost of NASA support for each CRS launch. If you look more closely, you’ll see that in costing CRS launches in the manner Shuttle launches are, CRS launch costs jump dramatically, from $12,143/kg to $18,000/kg.

    Since there is no study or published analysis to rebut the May 26, 2011 House Space Subcommittee hearing charter’s analysis of CRS payload costs, we are left as our only choice to rely upon the House numbers for now.

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