SLS: What now?

“Okay, wise guy, the SLS hasn’t turned out, everyone knows that, what do we do now?” Quoth some person on the internet.

This blog is a followup to my previous post on the SLS and its fundamentally compromised architecture. I have been pleasantly surprised by positive responses and feel that I might have gotten closer to the mark than I at first thought. Indeed, not one week later, former JSC director George Abbey wrote a policy paper focusing on SLS’s excessive costs.

The SLS is both a cause and symptom of deeply challenging issues within US space flight, and identifying them is very different from solving them. In particular, I’m quite aware of my own blind spots and limitations, and this post is not intended to be overly prescriptive. In the style of my other posts on the state of the conversation in space exploration I believe I can at least offer a commentary on what the right questions to ask actually are, and use these to sketch the solution space. As always, this blog represents only my own opinions.

First we have to decide if we want to have an ambitious human space exploration program, and the operational effectiveness to enable it within NASA. It is far from uncontroversial whether NASA should fly humans to space, whether as a matter of national prestige or in service of scientific exploration. If human space flight must be done, is buying flights from Roscosmos adequate? Or must we project national power by launching astronauts on US rockets from US soil, and launching them higher and faster and further than anyone else?

I personally believe that space exploration is the final frontier, it is important and necessary, and that the US is the best nation-level organization to do it. I believe that NASA should continue to lead in this domain, but that a variety of intrinsic and extrinsic challenges mean that this role is far from preordained.

As an example, today SpaceX successfully landed a Starship prototype in Texas. SpaceX has the talent and resources to effect a step change in human space flight capability. They continue to broadcast their incredibly unsubtle intentions in this arena, and they act like they intend to succeed.

I’ve asked around and I’m yet to find an organizational body, at any level or at any NASA center, which is studying the implications of Starship being operational. It’s not 100% certain at this point, but it’s worth a hedge, and most of the public statements out of senior leadership, officially compelled to shill for SLS, seem to exist in a separate universe where Falcon 9 hasn’t even ever landed.

It’s not hard to find a hungry scientist who literally salivates at the prospect of a 100 T instrument payload to, say, Saturn. The upside is fairly clear. But what of the downside? What does NASA do with teams that cost a few billion dollars a year to feed and whose main expertise is building rockets and space probes whose entire architectural philosophy is threatened by current launch costs, let alone the order of magnitude improvement that’s in the pipeline?

The Perseverance Mars rover cost $2.4 billion, which works out to a few thousand salaries for just under a decade. Thousands of people are needed to build this rover because landing stuff on Mars is so hard that subsystem masses must be tracked to a tenth of a gram, on a system that weighs a tonne. The whole thing is meticulously handcrafted from custom silicon, PCBs, titanium tubes, motors, cameras, and other awe-inspiring instruments. Starship will be able to land 100 of them per flight. Now what? How can NASA feed a team that makes one feather light rover per decade for a billion dollars if the demand just jumped by a factor of a thousand and the unit cost fell by the same amount? Set up a production line? Work out how to make them with a team of ten? Build one every two weeks?

In short, in a world where SLS’s ongoing failure is justified and/or ignored while Starship races towards transformational capabilities, NASA needs to think very deeply about its place in a human spaceflight program that appears poised to proceed without NASA at its center.

The problem is one of culture.

Simply put, culture is what is seen to be punished and rewarded within an organization. This is explicitly distinct from the vision statement poster pinned to the wall in the HR department. It is clear enough that, like many organizations, NASA has steadily evolved towards extreme caution on both an individual and collective level, embodied in the personal attributes of its leadership. For example, see the sort of political obsequiousness embodied in the official lunar gateway paper, or in Bridenstine’s apparent plain faced repetition of Trump’s ludicrous lies on national television. Yes, everyone knows why he acceded to Trump’s technically illiterate real time improvisation of space policy. Jim’s no use to anyone doing a Scaramucci. But can you imagine the harm this does to the morale and integrity of an organization that ostensibly exists to engineer spaceships to fly to other planets? To see senior leaders fall over themselves to flatter and debase themselves in this manner, even (or especially) ones as popular and effective as Bridenstine? Who is promoted at NASA? Who is rewarded? The astronauts who never, ever make even a tiny fuss about safety lapses that endanger their lives? The managers who can spin a political gimmick to the benefit of their constituents? Or allow themselves to be strong armed into supporting policies that they know are incompatible with mission success?

In contrast, the one person who everyone can agree has been excluded from the Biden administration’s shortlist for NASA Administrator is former Deputy Administrator Lori Garver. Among a field of competent candidates with impeccable credentials and impressive track records, Garver “made enemies” by persistently asking insightful questions about a variety of troubled programs which now, a decade later, are still troubled. Garver’s critics may accuse her of occasional tactlessness, but at least she didn’t squander the agency’s technical integrity and saddle it with a ruinously expensive and dangerous rocket to nowhere. A track record of integrity, speaking truth to power, defending value for the US taxpayer, and a deep understanding of the cultural challenges at NASA. And naturally, the one person excluded from the shortlist, relentlessly punished, banished for life.

Of course, Garver as NASA Administrator wouldn’t magically cure the patient. On the other hand, her systematic exclusion is a symptom of a will to never ever get better. If NASA wants to be in the room where SpaceX’s Mars plans happen, a culture that celebrates principled dissent and champions personal courage is a good start. NASA and JPL’s incredible recent successes with Perseverance show the value of a culture that uplifts individuality and brilliance in engineering. We could do worse than senior leadership who can sell their technical authority to Congress the way Adam Steltzner sold Skycrane.

Let’s talk about some specifics. Here are some ideas that I think, combined with top down cultural shifts, could help right the ship.

We need a decadal survey for human spaceflight. We have a decadal survey for Earth Sciences, Planetary Science, and Astronomy and Astrophysics. A decadal survey is a deliberative mechanism for science communities to attain consensus and provide measured recommendations to funding bodies. It’s not perfect (sorry Venus scientists!) but it’s a lot better than back room political machinations of the sort that led to the demise of the Superconducting Super Collider. Scientists and engineers in human spaceflight need to put their heads together and rank questions in technology, physiology, and architecture. We’ve been talking about a spinning artificial gravity lab on the ISS for 30 years, and we still don’t have any real data on how the mammalian life cycle progresses at partial gravity. Is radiation really a thing? Do we need self-replicating robots to close the industrial stack on Mars? Let’s draw up this document and use it to defend human spaceflight from programmatic whiplash.

SLS is nearly finished, or so they say. Since we have it, why not launch it? In my opinion, we should ship the hardware to the cape, lay it flat next to Atlantis, and throw a shed over it. It can serve as a memorial for the lost half century and a warning to future generations of designers who think they are ready to write the final word on rockets. “Everyone knows what’s wrong with these rockets. Do you think you are better than their designers?”

SLS is expensive because an army of people work on it. Do we want to fire them all? I don’t think so. NASA exists partly to fulfill a national strategic need for a standing army of technically elite engineers and technicians, which are otherwise hard to generate in a hurry when they are really needed. But if we’re going to spend billions of dollars a year on ten thousand salaries, we need to think about how drastically their work places need to be reorganized to facilitate an order of magnitude (or two) improvement in productivity. Which, incidentally, is also a strategic imperative.

I’m not the first to say this – former administrator Dan Goldin went on his Faster, Better, Cheaper crusade nearly 30 years ago. NASA as an organization specializes in projects that are just on the cusp of the possible, and they cost a lot of money. But the least we can do is minimize unnecessary difficulty and complexity, in particular by leveraging contemporary advances made in the commercial space.

There are many ways to help an organization recover its operational effectiveness and retrain its people to aggressively suck dead time out of projects. Small teams. Accountability. Short time frames, with projects that last for a year or less. Iteration as a design philosophy. Cost and schedule sensitive Key Performance Indicators. Bonuses for innovation and streamlining procedures. Public private partnerships based on the successful Commercial Cargo and Crew programs.

There is urgency to this work. If SpaceX’s Starship reaches orbit before 2024, there is a good chance that a billion dollars will buy 2000 T of cargo on Mars, or the Moon, by 2030. What part of the Mars or Moon base will NASA want to build, and how can they deliver 2000 T of anything cheaply enough to be worth the effort? The required organizational transition is equivalent in scope and difficulty to the Apollo program, and will be made or broken during the tenure of the next NASA administrator.

12 thoughts on “SLS: What now?

  1. I want an estimate for how much the SN8, SN9, SN10 prototypes cost to build. I can’t find estimates online. Assuming Raptors cost $1.5M, the body and avionics $2M, and labour around $2M, the total cost is around $8.5M. Being even more conservative, let’s say the cost is $10M. So three of those is around $30M. Let’s say all the other equipment cost 75% of that – $25M. Add $5M just for funzies. Is $60M (or a single F9 price) a good guesstimate?

    What is your estimate? I can’t see it exceeding $100M. SLS looks like a dumpster fire in comparison.


    1. If the program employs 1000 people and currently produces 20 Starships a year then it works out to $5-$15m each. Though these ones are not quite fully featured…


      1. $5-$15m each – that’s crazy! What about life support and ISRU? Do you think they’ll just send fuel to Mars at first to ensure crew return? SpaceX hasn’t given any details regarding ISRU or life support and it feels like it’s the hardest part about the whole thing.


  2. What a superb question?

    Who will want 2000 tons of cargo delivered to Mars or the moon in 2030?
    And what would it be?
    Or (IMHO) much more sensibly that weight delivered to Deimos or one of the earth crossing asteroids
    Or even 3753 Cruithne


  3. Starship’s progress is astounding but should I be worried at all that SpaceX could encounter more issues using 28 engines on their booster than Elon and company originally thought?


    1. They undoubtedly will, just as they have with the attempted landings of SN8-10. Discovering new ways for early prototypes to fail is not at all unexpected. But “Failure is an option here. If things are not failing, you are not innovating.” Musk’s philosophy of rapid iteration and testing to failure using cheap prototypes to work the early kinks out before moving on to more expensive prototypes is likely to see them through to success just as it did with learning to land the Falcon 9.


    2. Falcon Heavy has … 28 engines. It seems to fly just fine. And Starship will have more redundancy.


  4. The question “What do we do now? I think may have an easy answer. Nothing. Leave it all to SpaceX and maybe some other new companies. Its worked extraordinarily well so far. Its been ten years since SpaceX shattered the myth that spaceflight requires government scale investment and decades of R & D. Now there’s a revolution nobody seemed to notice. It comes as no surprise to read in this article that the old guard are pretending it just didn’t happen. What has been so shocking is how unknown this revolution remains despite being right there in front of us all. There seems to be some vail over everybody’s sight!


  5. Casey, I enjoyed your recent appearance (if that word is applies for audio-only format!) on the Space Show.

    I can give you chapter and verse for Elon Musk’s offer to build an SLS equivalent for $2.5 billion:,%20Merlin

    (in case the awkward URL above doesn’t work for you, just go to Bill Harwood’s blog entry for 6 December 2010 at

    and look for the link to the relevant Aviation Week story).

    I would add that at the time, ULA was offering super-heavy versions of its EELVs, so even for those who thought SpaceX was too new a player to be trusted, there were commercial alternatives to SLS. The bigger issue, though, is that the need for an SLS-sized rocket was never established in the first place.


  6. You talk about “the prospect of a 100 T instrument payload to, say, Saturn”… but isn’t Starship’s delta-v capability pretty marginal for most destinations other than Mars or Venus?

    If you fuel Starship up in a highly elliptical Earth orbit, you can get to the vicinity of any planet (with Mercury being unreachable with a full payload without a gravity assist), but just barely… it won’t get you to an orbit of any of the moons, or of to a low orbit of the planet, even with no payload.

    I suppose that can potentially be remedied by carrying an additional booster as a payload… but then you’re talking considerably less that 100 T of instruments being delivered.

    I love the vision (which you articulated in a recent interview) of Starships carrying tons of scientific payloads to all the planets. But, it seems like you’re implicitly overstating Starship’s capabilities, given how much delta-v is required for many of the scientific missions one would want to do.

    Or, am I missing something? Maybe you’re imagining aerobraking in the upper atmosphere of gas giants?


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