Second Guessing Starship

There seem to be two extremes when it comes to Elon Musk and SpaceX. There are those that believe everything Elon tries will work because–ELON. There are those that believe SpaceX has reached the end of its’ lucky tether because–ELON. The extreme factions make it a bit more difficult for those of us that try to think, or second guess , what will unfold in the SpaceX universe.

Starship typifies the extremes. Some believe that Starship will be in full service within a year delivering 100+ ton payloads multiple times per day at a cost per flight well under even Falcon9. There are others that don’t see Starship becoming operational in this decade. Again the extreme factions throw a bit more murk out there to peer through.

There are still quite a few of us somewhere in the middle that doubt both extremes. For my part, I suspect it will become operational mid decade at a price point above Falcon9 per launch, though well under it per unit of mass. For heavy lift, SLS isn’t even on the radar of those that wish to open up space as a place for humanity to live, work, and grow.

Where I second guess Starship and Superheavy is on the sequence used in the development path. I felt there was a good bit of hubris in going for the largest launch vehicle in history with several concurrent new technologies in one jump. I did not strongly hold these opinions until seeing the difficulties with ground support equipment, regulatory approvals, and ersatz-environmentalist tantrums. Hence Second Guessing. This is not a recommendation going forward, rather a hindsight thought.

Considering that many of the issues are caused by the sheer size of the vehicle, it is worth considering what could have been done with a more modest precursor vehicle. For this post, I am suggesting a Falcon9 type layout, though that may not be the best possible size or configuration. 9 Raptor engines first stage and one Raptor vac on the expended second stage.

(simplifying) Assuming that Raptor has twice the thrust and a higher Isp than the Merlin, the Falcon/Raptor (FR) should have a bit over twice the payload of the Falcon9. Assuming that Elon and company have accurately forecast that Starship will cost less per launch than Falcon, then the configuration here should have a launch cost about 25% that of Falcon9. Assuming that the 3 launches per day per Superheavy are not a total fantasy, then the FR booster should be able to hit a cadence of once per day with RTLS.

Assuming that had been done, what would it have gained? For starters, the Starship test flights last year would have been first stage FR test flights. Those test flights could have been followed by full up test flights by the end of last year with operational missions starting early this year. By now it seems reasonable that launch cadence could be approaching that of the Falcon9.

Construction of (hand waving) 5 meter diameter first stages would take about half the time and materials per unit of height as either Starship or the Superheavy boosters. Remember the problems getting the welds right early on? Learning curve (time) could possibly been halved. Along with smaller faster ground equipment construction with about a quarter of the propellant volume requirements per test. Problems could have been found and addressed even sooner than the current gargantuan effort.

Regulators seem to be having problems with the size of the Superheavy Starship combo. Kilotons of equivalent explosive seems to come up on a regular basis. Decibels created by the largest launch vehicle in history gets some of them going. It seems possible that a FR could be passed off as the next logical Falcon upgrade. Somewhat larger to accommodate the more environmentally friendly fuels. A diameter and height that could (theoretically) use the same launch pads as Falcon9. The higher payload is just a byproduct of more efficient engines, nothing to worry about. Pads at the cape and Vandenberg could be modified relatively quickly to handle both types of Falcon

Environmentalists, real and ersatz, would have a much harder time fighting a vehicle that was just a bit larger than what was in the original EIS, really just a minor upgrade in the scheme of things. With no immediate need for massive expansion due to the smaller vehicle, there would have been far less they could try to block. Everything necessary being permitted and underway before drawing their serious attention.

If the Superheavy/Starship combo hits full operational status shortly, then most everything in this post can be used to ridicule me. If the costs per launch are in the single digit millions within a couple of years, the ridicule can be redoubled. I would accept that ridicule with a smile, and possibly a few belly laughs. I do not expect it to just coast to a smooth operational status in a short time frame. If I am right, then a smaller ship as the FR could be finding the problems with operating an extreme performance methane engine launch vehicle at a quarter of the engine/airframe cost per boom/lesson. And those lessons could have been accumulating starting about a year ago. This is not casting shade on SpaceX, this is about biting off a huge chunk that may be too much to swallow easily for anybody.

It seems that the strongest argument has to do with Starlink2. If FR were operational by now, it could be launching 100 or so Starlink1 per flight or ~50 of the Starlink2 as they come on line. Assuming that Superheavy/Starship could operate for the same cost per launch as Falcon9, then this purported FR should cost about 25% of that. So Starlink1 would be hitting orbit at roughly 12-13% of the launch cost per sat as those launched on Falcon9. Starlink2 at a little over twice the mass would cost perhaps 30% of what it costs to do a Starlink1 with Falcon9. If Superheavy/Starship has a suggested turn around of up to 3 times per day, then it seems that an FR could hit once per day even while ironing out operational bugs. One ship flying daily with 40 Starlink2 on board would be placing 200 of them per 5 day week. That would be 10,000 Starlink2 per airframe per year. With the current build rate at Boca, there would be no need to rely on one airframe. Perhaps three each at Boca, the Cape, and Vandenberg, with Wallops and Kodiak if needed.

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johnhare

johnhare

I do construction for a living and aerospace as an occasional hobby. I am an inventor and a bit of an entrepreneur. I've been self employed since the 1980s and working in concrete since the 1970s. When I grow up, I want to work with rockets and spacecraft. I did a stupid rocket trick a few decades back and decided not to try another hot fire without adult supervision. Haven't located much of that as we are all big kids when working with our passions.
johnhare

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johnhare

About johnhare

I do construction for a living and aerospace as an occasional hobby. I am an inventor and a bit of an entrepreneur. I've been self employed since the 1980s and working in concrete since the 1970s. When I grow up, I want to work with rockets and spacecraft. I did a stupid rocket trick a few decades back and decided not to try another hot fire without adult supervision. Haven't located much of that as we are all big kids when working with our passions.
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21 Responses to Second Guessing Starship

  1. Larry LaVanway says:

    Hi,

    I just discovered your blog & I really like it so far. For this blog post though, I think a certain percentage of your argument falls apart because of three things you haven’t seemed to consider: fairing volumes, the nature of human labor costs, and the nature of human beings generally. The first point is longer, but the other two are short.

    1) Payload fairing volumes.

    On the practical level in the current scenario, even if “Falcon Raptor” had double the payload lift capacity to LEO compared to Falcon Block 5, you mention that it’d be using basically the same fairing as the current Falcon Block 5. If so, then I’m pretty sure there simply wouldn’t be enough room for notably more Starlink satellites to fit in the fairing stack. Maybe you’d be able to squeeze in an extra one or two, but certainly not double.

    On an abstract level, people often say that SpaceX wants to drive down “launch costs” (usually framed as “launch cost per kg of payload to LEO/GEO/TLI/LLO/TMI/LMO, etc.”) by orders of magnitude. However, that’s too vague of a statement & doesn’t get to the *true* dynamic of what I think is going on. Particularly for large scale spaceflight projects, the “launch cost” usually represents just 5-10% of the TOTAL costs involved. So even if “launch costs” were literally zero, we’re still looking at a modest overall discount. The thing that will *REALLY* move the needle is if the, “TOTAL ALL-IN cost per kg of payload to LEO/GEO/TLI/LLO/TMI/LMO, etc.”–which of course includes development & manufacturing costs–is driven down by orders of magnitude.

    It’s clear that you know all of this already, as you spent time in your blog post rightfully talking about the saved development & manufacturing time that “Falcon Raptor” might yield vs. StarShip/SuperHeavy. Ironically though, you seem to be glossing over how critical a role payload fairing volumes contribute to that whole dynamic. Whatever the merits of pursuing a “Falcon Raptor” first before pursuing SS/SH, a huge down-side is that it’s not doing a thing to unlock the “volume constraint” that makes orbital mega-projects nearly impossible & undoubtedly drives up the cost of most other payloads b/c they have to be miniaturized, fold like oragami into tiny fairings, etc. In contrast, with the volumes afforded by SS/SH, SpaceX could in theory charge MORE to launch payload per kg to orbit than current rates, but *still* drive down the overall costs of “sending useful payload to orbit” by an enormous amount, so long as the savings on the payload design/development/manufacturing side significantly outweighed the increased “launch costs.”

    2) A smaller point, but I think you’re not fully factoring in the nature of human labor costs. As with #1, you obviously hit on that somewhat, as you point to the lower development/manufacturing costs as a factor favoring “Falcon Raptor” over SS/SH. But it seems to me a lot of the ongoing labor costs of running an high cadence “Falcon Raptor” launch program wouldn’t be much lower than running an ongoing SS/SH program. In fact, it might be notably more expensive b/c that “Falcon Raptor” program would have to be moving along at a much higher cadence than a SS/SH program to make up for the lack of volume & lift capacity if SpaceX were to yeet the same amount of raw tonnage per year off-planet. I don’t know if it’d be enough to totally erase the cheaper development/manufacturing costs, but at minimum I think it’d eat into any advantage “Falcon Raptor” has in that department.

    3) Last, there’s just plain old human nature. What’s that saying? “Nothing is as permanent as a temporary government program.”? SpaceX isn’t a government program, and I know they have an excellent record of continuing to iterate a platform after it becomes “operational” (Falcon 9 Block 5 being a prime example). However, Elon Musk as an individual & the current culture of SpaceX won’t last forever. I hope it won’t happen, but there’s a non-zero chance that within 15-20 years, SpaceX will become far more focused on their quarterly profits than they are on abstract goals with a time horizon of decades & centuries. If that happened at the same time they also had a wildly successful “Falcon Raptor” program utterly dominating the spacelaunch industry in their portfolio, I doubt the executives & shareholders would have the appetite for another high risk mega-development project to make the jump from “Falcon Raptor” to SS/SH.

    Bottom Line: Yes, there are certainly risks in going for SS/SH without doing a more incremental step beyond Falcon 9 Block 5 first. But there are *different* risks associated with going the more incremental route too. The more cautious theoretical approach you outlined might STILL come out on top overall. But since most of the risks associated with that approach are back-loaded & most of the SS/SH risk are front-loaded, I think you may have inadvertently missed/discounted some of them & as a result might be over-valuing the merits of the incremental “Falcon Raptor” path.

  2. johnhare johnhare says:

    Thanks for commenting. We were far more prolific a decade or so back. The bloggers here all have time eating businesses. Also, if you are critical, that’s what comment sections are good for. Far too many blogs are echo chambers of the prevailing theme.

    On fairing volumes, I never mentioned them. The 5 meters I suggested was for the first stage. Assuming the FR worked and was worth using, Fairing would probably go to 7 or 8 meters depending on need and convenience.

    Launch costs are a tiny component of “flagship” programs and a lot of legacy systems. For people and organizations that are paying attention, payload costs are dropping as well. Starlink costs seem to be a fraction the cost of traditional comsats, which makes launch costs a critical factor. Starlink1 couldn’t have flown on legacy launchers, and Starlink2 couldn’t have come close to a business case.

    On your point 2, a fully developed and operational Starship could put more tonnage to orbit per man hour and dollar. That requires that it become fully developed and operational in a timely manner. Also it requires that there be sufficient payloads to make it worthwhile, emphasis on pay. Flight rate of Falcon Heavy to date is not encouraging. It is quite possible to have the biggest and best launch vehicle in existence circa 2024 without enough paying work to recover the investment. Clearly Starlink2 would use up the capacity in a hurry. Vehicles, launch pads, and personnel sitting idle are an expensive luxury.

    Your point 3 is quite possible.

    I am in the process of getting a new business off the ground while running my regular business. Too much time and/or cost to market and I’m in a losing situation, so we’re squeezing pennies and pushing. I’m not betting the company, but close to it. I see the same possibilities and hazards with Starship.

  3. Jonathan Goff Jonathan Goff says:

    John,
    I’m with you that if SpaceX had picked a more reasonably sized first attempt at a fully-reusable vehicle, that they likely would be further along. At the end of the day, the economic benefit of a vehicle like Starship is far more dependent on how reusable it ends up being than on how big it is per se. A 10-20mT to LEO full RLV would still beat the pants off of almost any other vehicle. I hope SpaceX still makes Starship work even though I think they made their life harder than it needs to be. I also hope though that one of the other full RLV aspirants will be successful with something more modest.
    ~Jon

  4. Dave Salt says:

    I think the size of Starship was driven primarily by Mars mission logistics, rather than EO missions like Starlink. However, if someone had the wherewithal, maybe a B-to-B agreement to license Starship technologies could see your FR concept developed as a complementary launch system to enable EO industrialization?

  5. johnhare john hare says:

    Part of my myopia is that I don’t buy the Mars mission logistics. A laudable vision is not the same as a viable business plan. Unless a massive market emerges in a timely manner that I can’t currently envision, the projected capabilities of Starship are unlikely to be well utilized.

    To me it smacks of designing THE transatlantic ship in the year 1600. By the time the capabilities of Starship can be utilized for Mars, the technology might be obsolete and uncompetitive. Also I don’t buy the super lowball cost numbers for Starship that many throw around. I can believe that lessons learned and better technology will result in a vehicle with abnormally low prices per unit without buying into the $10.00/kg.

    The FR concept for this post was just for ease of conversation. I suspect a somewhat smaller vehicle would make more economic sense for someone to develop.

  6. Dave Salt says:

    I don’t disagree with anything you say. Unfortunately, the guy who has the power to say “make it so” has Mars monomania, which is why Starship is so big. Existing and future Earth/Moon markets were deemed insufficient to justify the economics, so they ‘invented’ Starlink.

  7. johnhare john hare says:

    I can see where massive markets are possible in the Earth/Moon volume. But they all involve humans. (probably exist in my imagination more than in reality)And are unlikely to keep the troops inspired anywhere close to the Mars vision.

    Vegas in the sky with zero gee live shows, gambling, and forbidden pleasures of all kinds.
    Microgravity Mixed Martial Arts on pay per view with live audience.
    Sports of various kinds, both pro and for individuals.

    Manufacturing of something I am unaware of except for the various “forward looking statements”

    Lunar retirement homes
    Lunar sports.

    If an actual viable business plan is developed for Solar Power Satellites
    Private knowledge of a lucrative mining opportunity He3, platinum group, radioactives, etc.

  8. Dave Salt says:

    People have been discussing potential markets in the Earth/Moon volume for many decades that cover much of what you mention and more, for example…
    https://www.nasa.gov/sites/default/files/atoms/files/csts_1994.pdf

    The problem has always been the cost/reliability/availability of space access, though ventures like SpaceX are now beginning to break down that barrier.

  9. johnhare john hare says:

    I downloaded the file and probably have time to at least skim it in the next couple of days while the hurricane dumps rain on us. Thanks, been away from most discussion for too long.

  10. Robert Clark says:

    I agree with your conclusions that a two stage vehicle using the Starship as the booster and a smaller upper stage can lift quite a large amount of payload to LEO. I think though we can get as much as 100 tons to LEO as an expendable. The reason is an expendable Starship with no reusability systems and even no fairing, but with additional engines added on for ground launch, might actually mass ~50 tons, not the 100 – 120 tons often mentioned.

    See discussion here:

    The nature of the true dry mass of the Starship.
    http://exoscientist.blogspot.com/2022/09/the-nature-of-true-dry-mass-of-starship.html

    Robert Clark

  11. Joe Carroll says:

    Like John Hare, I find myself far from either extreme. Starship may be a bridge too far, even for Elon. And if Starship is successful, it will have limited (but important) roles. Here are 9 theses about Starship that I think likely:

    1. Starship’s main business will be launching from Earth to LEO (& back), not beyond.
    2. Starship (rev 1.0) has 2.3X shuttle’s cargo volume, but >4.3X its heaviest payload.
    3. Once $/kg drops ~4-fold, users will focus more on reliability & launch vibrations.
    4. “Startankers” can cost & weigh ~1/3 less & deliver ~1/3 more prop than Starships.
    5. Most early propellant transfers will be from one Startanker to one Falcon stage 2.
    6. Later transfers will be to lighter (inflatable?) stages, with lower T/W than Starship.
    7. It is better to find uses for empty stages far from LEO than to return them to earth.
    8. 23 Dragons & >80 Falcons flew for 9 years before crews. Starship may need more.
    9. Until Starship is safe enough, “MegaDragons” might launch on top of Startankers.

  12. Ken Brown says:

    I’m seeing too many articles and comments that meld together the technical and economic aspects of Starship that get very confusing. For Starship to make any sense, there has to be a business case for it that isn’t a lot of “build it and they will come” or “we need to colonize Mars and become a two planet species”. Jon hits a key point that launch cadence can be a huge thing. That’s been a big argument against SLS as that system is scheduled to have so few launches that maintaining staff and facilities becomes the dominate costs of the program and far exceed the incremental costs of each launch. A launch vehicle that has an incrementally higher cost per kg can be less expensive on the bottom line for all of the costs taken as a whole. Just staff utilization and training costs are cut way back. There’s less infrastructure to keep maintained in a coastal environment that is very hard on structures.

    Starship’s business case to date is Starlink. From what I’ve seen, the business case for Starlink is on the tenuous side which takes a huge reason for Starship off of the table. I’m convinced that all of Elon’s Mars dreams are not viable. While I’d by captivated by seeing humans make bootprints on the Red Planet, I don’t see colonies working out at all and agree with those that feel robotic missions and sample return missions are the best way forward until/unless something such as nuclear propulsion becomes a reality and missions are under acceleration for the whole trip to contribute to astronaut health and to get the travel times down to what can be considered reasonable. Shorter transit times will also effectively lengthen launch windows.

    Advancements in electronics has reduced the size and mass of systems on satellites. About the only thing that hasn’t lost as much are optics for government spy sats. Maybe if they can come up with transparent Aluminum to make lenses from instead of glass things could catch up there too. I get that it can be simpler to not need to fold up spacecraft/rovers/etc but there’s still the issue of how many times that’s needed. Solar PV arrays and heat radiators will still needed to be folded up as they are far too large and aren’t substantial enough to survive the accelerations at launch.

    The environmental aspects of Starship are going to be known before too long. With Elon’s game plan of building fast and blowing things up, there may be data in the not too distant future about how bad a full stack exploding might be. I’m not happy that those lessons are likely to be learned in the midst of several wildlife preserves. It might also create problems by being so near an international border where people live and emergency services might not be robust enough in the case of an accident.

  13. Roga says:

    Some good points here. There was a ~few year period during Raptor development where they were developing a 91 ton subscale version. A production version might have been 120-150t which seems like it would be perfect for an even simpler evolution – a 5m methalox 2nd stage on the existing F9 or FH booster. Lots of advantages especially to a 2nd stage optimized to the FH booster. A heavier stage 2 would mean lower staging velocity and distance, making center core recovery more tractable. Using methalox staged combustion instead of kerolox gas gen on the 2nd stage is far higher marginal benefit than on the booster stage, and covers an area where F9 is currently weak (direct-to-GEO and deep space). The center cores already have different structural design than side cores and single sticks, so you could beef it up without affecting vanilla kerolox F9 payloads in the meantime. You are likely looking at around 50t to orbit expendable, or if you want to go for a recoverable 2nd stage you’re probably matching F9 single stick drone ship. And like you said, if this works out the obvious next step is a 5-7m Raptor booster, but you can bootstrap development and much of the ground equipment is there.

    It’s clearly not a “go to Mars” step. The extra horizontal staging will have worse reliability long-term, and all the downrange recovery could be a challenge. But like you said, the size of SH makes it a much harder sell for RTLS for nearby residents. I think there’s definitely a case to be made that getting better and more efficient a launching rockets is building on strength and not totally ignoring the realities of the market. If SpaceX could have focused on driving down the cost of recovery and refurb, and got enough marginal lift to reuse LEO 2nd stages, I think the economies of scale are much more flexible than those with Starship.

  14. Sam says:

    I think Larry LaVanway has some goods points, especially 2 and 3.

    I note that even if starship does not lift all that’s planned, you can’t lift more in a smaller rocket, but you can always lift less in a bigger one.

  15. johnhare johnhare says:

    Actually you can’t always lift less in a bigger one.

    If it takes too long in development to lift the load.

    If the various factors make it too expensive to operate for a small payload to return revenue.

    If it fails in development or in acquiring necessary permits to operate.

    There are always more ways to fail than to succeed. Starship is more likely to succeed, but it may not be in as timely a manner as many expect. Or on the budget that many expect. Or the market may not support the delivered capability.

    My best guess is that it will technically succeed and also have market and permitting problems.

  16. gbaikie says:

    –Dave Salt says:
    September 26, 2022 at 4:47 am

    I don’t disagree with anything you say. Unfortunately, the guy who has the power to say “make it so” has Mars monomania, which is why Starship is so big. Existing and future Earth/Moon markets were deemed insufficient to justify the economics, so they ‘invented’ Starlink.–

    The problem is we still don’t know if the Moon has mineable water.
    The Moon could have more mineable water, than Mars.
    But Mars needs mineable water, or can’t have human settlement on Mars.
    Also have to know if people can live with Mars gravity.

    Musk could/should build an artificial gravity station using Falcon- 9.
    Hmm does this work:
    http://www.transterrestrial.com/2023/04/26/developing-space-2/?replytocom=516078#respond

  17. gbaikie says:

    The Moon needs about 1 million tons of mineable in one location, it could have a billion
    of tons. Mars needs a few billion of tons of mineable water in one location- or doesn’t have mineable water. It could have a trillion tons in one location on Mars.
    A location on Mars is within 100 km. And location on Moon is within 10 km.

    It’s all about economic of scale. Mars water needs to be about $1000 per ton, Lunar water
    could as much as $500,000 per ton [maybe higher, better if lower].
    So million tons of Mars water for cost 1 billion dollar, and make profit, because you make millions of tons of water and sell the water as fast as you mine it- you sell it before it’s actually mined. Moon water is around 10,000 tons and you sell it as rocket fuel [which require a lot electrical power- can’t sell it as fast as could mine it, you have start with hundreds of tons and get to 1000 tons as fast as you can, within several years. But if there more of it, maybe start at thousand of tons per year, sell it cheaper, and get to 10,000 tons within year- requiring massive amount electrical power. And/or export water from the Moon, make rocket fuel in orbit or even at Venus orbit.

  18. Kenneth Ferland says:

    Subsequent events look to be validating a lot of the sceptisim of StarShip, the most optimistic completion dates have already passed and the resent anouncement that the vehicle needs to be stretched and achive higher thrust to even match the original payload claims is a major red flag. I personaly estimate a high likelyhood of complete project failure at this point if a major technical hudle is hit and investor cash dries up. Musks social capitol has tumbled greatly along with the valuation of Tesla and Twitter which makes him far less attractive to the venture capitol market.

  19. Jonathan Goff Jonathan Goff says:

    Ken,
    I’m not *that* pessimistic. I think it’s highly unlikely that they’ll run out of willing investors anytime soon. That said, they’re also pretty close to a point where they could field a partially reusable Starship. If they did that, they could work on upper stage reuse as a series of post-flight demo missions (kind of like how they figured out F9 first stage reuse), stretched out over a few years of launching Starlinks, and building up the tech for their HLS mission. There’s a lot of intermediate levels of partial success between Starship gets totally canceled, and Starship achieves all of its goals without a hitch.

    ~Jon

  20. johnhare john hare says:

    They would appear to be closer to upper stage recovery than I thought possible at this point. Booster recovery seems to be proceeding well, as most expected.

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