back to article No Falcon Way: NASA to stick with SLS, SpaceX more like space ex

NASA has categorically stated it will not dump the troubled Space Launch System (SLS) in favor of SpaceX's Falcon Heavy any time soon. The SLS is competing with the James Webb Space Telescope for the mission most delayed and over-budget. Answering a question from Shuttle Mission Control veteran Wayne Hale, NASA’s Human …

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  1. Michael Hoffmann Silver badge

    See also:

    Senate Launch System; pork-barreling; mid-term elections; "do as we say (private enterprise is always best), not as we do (feeding off the government troughs)"

    1. Mark 85

      Re: See also:

      There is that but also NASA's built in bureaucratic management and conservative (overly?) way of thinking. They don't like risks and like to go with those they have worked with a lot in the past. It's like an old manager I worked for.. PC's had, absolutely had to be IBM because IBM. He retired and suddenly the PC refresh budget dropped by using other companies with PC's just as reliable.

      1. Stevie

        Re: See also:

        There is that but also the fact that zero-g engineering is much harder to do than the sort we do on the ground, which translates into longer times, unforeseen "drop-dead" (until the next launch) problems and much more expense.

        "The first is that the Lunar Orbital Platform Gateway is still very much on the drawing board, so there is no reason why it could not be designed to be launched in smaller pieces."

        This can only be taken at face value in a 1940s-era Robert Heinlein story.

        1. DrMordrid

          Re: See also:

          The Gateway modules will be 4.5 meters, well withinthe 5.2 meter width of SpaceX's Falcon 9 and Falcon Heavy fairing, and its Power and Propulsion Element (module) must by spec mass less than 7,500 kg. Falcon Heavy can toss at least twice that mass to the Moon.

          Since Gateway will be launching in the mid-2020's SpaceX's BFR will also be an option, and it'll be even more capable than SLS of launching massive payloads to the Moon; 45 tonnes for SLS Block 2 (2028+) vs over 100 tonnes for BFR (2020-2022).

    2. This post has been deleted by its author

  2. Sorry that handle is already taken. Silver badge

    Convenient of them to ignore BFR when comparing payloads.

    1. ArrZarr Silver badge
      Happy

      The BFR is a glint in spaceX's eye - not something that meaningful comparisons can be made to a rocket that already exists.

      And if the BFR timescale is within 3 years of what Musk has said, I will eat my own hair. I would be overjoyed, just pretty certain that it's not happening.

      1. tiggity Silver badge

        @ ArrZarr

        And arguably the large payload SLS is, although not quite "glint in the eye", but not necessarily a sure and sudden thing.

        But on a more serious point, modular construction is good from repair / maintenance / replacement viewpoint.

        And having multiple launch providers cannot hurt - remove single point of failure possibility, get them to compete on cost to reduce budgets (obv fantasy with cozy SLS funding scenario, but you can always hope..) etc

        1. Randy Hudson

          Give NASA some credit. They were lifting twice the payload of the Flacon in the 60s.

          1. hplasm
            Devil

            Give NASA some credit.

            "They were lifting twice the payload of the Flacon in the 60s."

            Yeah, the Flacon was pretty disappointing... you never hear of it much.

      2. Spudley

        The BFR is a glint in spaceX's eye - not something that meaningful comparisons can be made to a rocket that already exists.

        And if the BFR timescale is within 3 years of what Musk has said, I will eat my own hair. I would be overjoyed, just pretty certain that it's not happening.

        SpaceX are already constructing the first BFR prototype, so I think the glint in the eye comment might be a little out-of-date. Sure it's not here yet, but neither is SLS. Musk has talked of it being tested next year.

        The first SLS to fly will (by current plans) be next year. But it will be the smallest size version, which only just beats Falcon Heavy. It will also be launched as a proof of concept, and not carry anything meaningful (there was some talk of putting crew on board the first launch, but that idea has sensibly been abandoned).

        It will take them *at least* another year to build a second SLS, by which time the BFR prototype will have been doing test hops for months.

        There are only enough engines stockpiled for them to build four SLS rockets. After that, they need to restart the production line if they want to launch any more. Aerojet have quoted them a billion to do that (not counting the cost of the actual engines that get built) and a build rate that will only allow one SLS launch every 18 months.

        If they really want to build this Lunar Gateway station they're talking about, it will take multiple flights, even allowing for it to be built in large "monolithic" pieces, so given the maximum possible flight rate imposed by engine build constraints, it will take them a decade to build it.

        Given all the above, BFR can be delayed for *years*, and it will *still* be a better platform and available soon than SLS for most of the missions planned for SLS.

      3. Anonymous Coward
        Anonymous Coward

        a rocket that already exists.

        But that rocket does not exist. BFR may well be ready before before the SLS.

        1. bombastic bob Silver badge
          Devil

          Re: a rocket that already exists.

          " BFR may well be ready before before the SLS."

          More true than not, when you compare government projects to private industry (in general).

          Back in the 80's, when I was in the Navy, the San Diego submarine base had an ongoing project to construct barracks for single officers. They were living at the barracks at another base a few miles away, or in apartments in the city. So this had been under construction for the entire time (>3 years) when I was at the San Diego base.

          In 1985, McDonalds got permission to construct one of their restaurants on base. It was up and running in about 3 months, from laying the foundation to flipping burgers. And, by comparison, the officer's barracks WAS NOT EVEN REMOTELY COMPLETED after 3 FORNICATING YEARS!

          That kinda says it all, I think. Musk wants to make money, so HIS "BFR" rockets will be designed, tested, flown, and approved LONG before NASA gets even REMOTELY close to having SLS ready.

          (without the 'urgency' of the space race, like it was in the 1960's, gummint projects will milk the funding for all it can, keeping people employed indefinitely regardless of how important or useful the jobs are, creating circular bureaucracies that justify one another's existence, and LOTS of spinning wheels without motion)

      4. Anonymous Coward
        Anonymous Coward

        BFR? Or SLS?

        "The BFR is a glint in spaceX's eye"

        Mmm... SpaceX started building BFR parts in 2017. The BFR is a lot more than just plans on a computer, and SpaceX - regardless of its over-optimistic boss - does get things done quicker than the usual suspects working on NASA contracts.

        "if the BFR timescale is within 3 years of what Musk has said, I will eat my own hair"

        Certainly Musk has form when it comes to being, shall we say, a little over-optimistic on development times. But then again, the SLS itself is already well behind the original schedule.

        Both the SLS and BFR are currently supposed to have their first flight next year - SpaceX is apparently planning a suborbital hop next year for the first BFR launch, while the SLS is scheduled to launch "no earlier" than 19th December 2019.

        I'd happily bet a small sum that neither rocket will fly until 2020.

        I've no idea how to judge the odds of which big rocket's most likely to go into service first. Maybe someone could toddle down to the bookies and place a bet? William Hill goes for this sort of thing...

        I've just had a look and found a curious thing here:

        https://www.nasa.gov/feature/nasa-s-lunar-outpost-will-extend-human-presence-in-deep-space

        NASA says that the first element of the Lunar Orbital Platform-Gateway is due to be launched in 2022. The thing is, that NASA article also says:

        "NASA plans to launch elements of the gateway on the agency’s Space Launch System or commercial rockets for assembly in space."

        - so NASA's statement from the 13th February 2018 seems to contradict NASA’s Human Spaceflight head honcho Bill Gerstenmaier's insistence on the 26th March 2018 that only the SLS will do.

        I think we're just going to have to wait and see what happens.

      5. DrMordrid

        BFR is sooner than you think

        Assuming BFR will be many years off is very ridky.

        BFS ship #1 is being assembled now in a temporary facility, and the full up San Pedro CA factory at Terminal Island should be ready in late 2019. Janicki Industries (B2, F-22, 787, B-21 Raider etc) does the large composite structure fabs (propellant tanks etc) near Seattle and ships them to SpaceX. One oversize (12 meters) LOX tank was tested to destruction, and passed.

        The Raptor methane engines have been on the test stand for almost 18 months, with partial funding from the USAF. Reports are good, with videos of stable burns dating to Sept. 2016.

      6. Sorry that handle is already taken. Silver badge

        @ArrZarr

        The BFR is a glint in spaceX's eye

        You might have noticed the same is true of SLS, other than the eye being NASA's (and its contractors').

        It's only fair to compare one non-existent launch vehicle to another.

    2. Alan Brown Silver badge

      "Convenient of them to ignore BFR when comparing payloads."

      Even if BFR doesn't come to fruition, Elon's made it clear that all the truss and core re-engineering they had to do to make FH work means that going from 2+1 to 4+1 is fairly trivial (and I suspect 6+1 is only slightly harder)

      Having the landing spaces is probably more complex.

  3. SteveCarr
    Alien

    NIH - Not Invented Here?

    Seems that NASA are scratching around looking for excuses for their platinum coated solution.

  4. Schultz
    Go

    It's about government control

    Due to obvious military applications, rocket technology used to be under government control. Musk and co. change the rules of the game, but it'll take a while until a new division of labor is established.

    I don't see the parallel development of different rockets as a problem -- the bigger question is whether the NASA is still capable to properly plan and budget their projects. Falcon heavy was late and over budget -- but you could expect that for rocket science done by amateurs, starting from scratch. NASA supposedly has all the know-how already. Or did all the competent engineers move to private industry by now?

    1. Anonymous Coward
      Anonymous Coward

      Re: It's about government control

      ... but you could expect that for rocket science done by amateurs...

      SpaceX's record on planning isn't very good. A long time ago their intention was to design a disposable booster that was so cheap to manufacture that it didn't matter that it was being thrown away every launch.

      To this end they did do some quite clever things, including the original design of their rocket engine bells. These were made by forming two bells from sheet, pressing one of them to be crinkly, fitting one inside the other and welding / brazing them together. This made all the cooling channels for the bell in only a few operations; quick and a lot cheaper than brazing miles and miles of tubing into the shape of a bell.

      Anyway, it turned out that they couldn't get the price down far enough that way. So disposability went, re-usability came in, hence their landing legs, etc.

      And with Falcon Heavy, they seriously underestimated the cost and difficulty of strapping 3 boosters next to each other. Anyone with any knowledge at all of aerodynamics could see that the loadings were going to be horrible. The interference drag between the boosters must be epic.

      There's also persistent talk of them not getting on top of a comprehensive quality control process. That led to their helium tank struts being rubbish (second stage explosion during first stage burn), and the helium tank failure on the launch pad (second stage explosion on the launch pad during static test; they'd not considered the full effect of super-cooled O2 on the carbon fibre tank). QC processes cost money, but no where near as much as losing a payload, or indeed a crew.

      And when it comes to getting Falcon / Falcon Heavy man rated, meetings between NASA and SpaceX on this topic didn't go well; turns out you can't just claim it's reliable, you have to do all the paperwork to demonstrate that. NASA's manned flight loses were entirely down to things that were thought to be reliable or impossible turning out not to be so. So they're not willing to let anyone fly on a booster that just happens to have been reliable for a few launches in succession. That was some time ago, reported on El Reg somewhere, and perhaps SpaceX have been working towards getting their paperwork in order since, but it's extremely hard to do it retrospectively.

      So yes, SpaceX's own history is no different to any other organisation trying to do things empirically. They've got caught out time and again.

      Musk is, first and foremost, a showman, and on no account must his extravagances be permitted to hurt anyone. When it comes to manned flight, boring and expensive but done properly must override exciting / cult-ish and cheap but with doubtful paperwork.

      NASA supposedly has all the know-how already. Or did all the competent engineers move to private industry by now?

      The work being done on SLS is being done by private industry on behalf of NASA, and they do have the knowledge to make a man-rated booster. Re-using Shuttle engine and solid booster designs is an excellent way to achieve this.

      NASA have never had large factories of their own for manufacturing rocket parts. They have the final assembly building, where it's all brought together.

      1. Flocke Kroes Silver badge

        Re: It's about pork

        You need SLS to launch Orion because you need Orion to justify SLS. You need SLS to launch LOPG because you need LOPG to justify SLS. You need the ALSTAR act (pdf) to make Marshall Space Centre "essential to sustaining and promoting US leadership in rocket propulsion" because Alabama needs to assure its supply of pork.

        I thought that the first crewed SLS mission would be delayed while the mobile launch platform for SLS block 1 got upgraded for SLS block 1B crew. Senator Shelby demonstrated outstanding pork farming skills by getting money for a second mobile launch platform. It must give everyone hope that pork for SLS missions will be found on top of pork for the SLS no matter what else has to be cancelled to make it happen.

        No mere showman could ever demonstrate pork farming skills like that even if he has taken half the launch market and saved NASA millions on commercial resupply.

        1. Dave 126 Silver badge

          Re: It's about pork

          You're right in that reusability isn't SpaceX's only way of saving cost - adding reinforcement by use of friction stir welding (instead of taking a thicker structure and milling away material) is another example.

          However, I'm not sure you've made the case for NASA's procurement process being safer for crews clearly enough. The Challenger disaster was famously due to there being too many managers sitting in between engineers in different organisations. When SpaceX has lost craft and payloads they've been able to chase down faults fairly rapidly due to their all in-house nature.

          SpaceX is no longer seeking to have the Falcon Heavy certified for manned missions, instead stating they're concentrating on doing so for the BFR once they've made it. The problem is that the market for BFR-scale payloads is smaller than for Falcon-scale payloads (modern electronics allow for smaller satellites). This means that it will take a longer time for the BFR rocket to accumulate the same number of successful unmanned launches as the Falcon has (approaching 50). One assumes that a large number of successful unmanned launches can only aid certification for crewed launches.

          1. Spudley

            Re: It's about pork

            The problem is that the market for BFR-scale payloads is smaller than for Falcon-scale payloads (modern electronics allow for smaller satellites). This means that it will take a longer time for the BFR rocket to accumulate the same number of successful unmanned launches as the Falcon has (approaching 50).

            If it costs less to fly the same weight on BFR than Falcon 9, as Musk has claimed it will, why wouldn't customers switch to using it, even if they're massively under-using the vehicle's capability?

            And if that cost can be cut further by using some of that extra capacity with ride sharing, that would surely sweeten the deal even further. In other words, I don't see why most clients won't switch to BFR almost immediately.

            There may be a few that want to stick with the F9 because it is known to be reliable, but that attitude won't last long; if you want proof, look how quickly SpaceX have been able to get people switching to re-used boosters.

            1. Flocke Kroes Silver badge

              Re: costs less to fly the same weight on BFR than Falcon 9

              Actually Musk's claim was that it will cost less to launch a BFR than a Falcon 1. The first time I heard that I thought "What the Falcon?", stepped the video back and listened to it again. Not lower launch cost per kilo to orbit, simply lower total launch cost. I did a quick web search for Falcon 1, chose the most expensive launch and added a bit for inflation. Musk is aiming for a BFR launch cost under $10M. Over the next few days I saw other comments showing people were just as shocked as I was. It was not a mistake. Elon did not forget to say "per kilo".

              If things go according to plan, you can put your falcon 9 payload in a BFR, add a Tesla Semi full of batteries for ballast, save $50M on launch costs and you get the Tesla Semi (with cargo) back on Earth. BFR will not be short of missions.

      2. Anonymous Coward
        Anonymous Coward

        "Re-using Shuttle engine and solid booster..."

        Sure, NASA is scraping any 40-50 years old technology because it looks its engineers are utterly incapable of developing and delivering anything newer and better. They had to shelve the Shuttle as well because they were no longer able to fly it safely - for lack of competences.

        NASA has to be fully rebooted. It was created when the military was trying to make rockets and made only disasters, but now NASA it's at that same point - because it has now exactly the same arrogant, stubborn bureaucratic and incompetent structure.

      3. Milton

        Re: It's about government control

        "NASA's manned flight loses were entirely down to things that were thought to be reliable or impossible turning out not to be so."

        In both cases—Columbia and Challenger—engineers had warned management about potentially lethal problems. Some engineers were horrifed when Nasa management decided to go ahead with the Challenger launch in such cold weather because they had explicitly warned about the cold O-ring risk. Repeated attempts to get DoD assets to inspect Columbia for damage, while in orbit, after the foam impact on its wing, were actively blocked by Nasa management. And it was Nasa managers who wrongly insisted that nothing could be done for the ship's crew if there were serious damage, when in fact, most unusually, on this occasion there was another bird (Atlantis I believe) well advanced in the launch process that could have rescued Columbia's crew.

        Two full crews died not because engineers said that the chances of failure were an utterly ridiculous one:billion (that was Nasa managers) but because politics had, as it always does, corrupted the process of honest and intelligent professionalism, and Nasa managers stopped listening to the people who actually knew best.

        So your statement would be more correct as:

        "NASA's manned flight loses were entirely down to things that were known to be dangerous but were ignored by management for squalid political reasons."

        Where politics and politicians are involved—the very antithesis of good, rational, intellectually honest thinking—good people die for nothing. Shuttle's problems were at root designed in by incessant cost-cutting and political interference, as it shrank from a sensible two-lifting-body design to the absurdly compromised firework that ended up killing more than two dozen people.

        Musk is far from perfect, but insofar as his outfit remains untainted by Nasa's politics and its woeful progress in manned spaceflight since Apollo, he deserves our support.

        1. Dave 126 Silver badge

          Re: It's about government control

          > Repeated attempts to get DoD assets to inspect Columbia for damage, while in orbit... ...on this occasion there was another bird (Atlantis I believe) well advanced in the launch process that could have rescued Columbia's crew.

          Only just. Possibly. It would have meant eeking out the Columbia's life support resources to the limit, and completing the Atlantis refit in faster than record time.

          Just out of interest, if we had had SpaceX then, would we have been able to get a suitable crew reentry vehicle to the Columbia?

        2. rh587

          Re: It's about government control

          And it was Nasa managers who wrongly insisted that nothing could be done for the ship's crew if there were serious damage, when in fact, most unusually, on this occasion there was another bird (Atlantis I believe) well advanced in the launch process that could have rescued Columbia's crew.

          Atlantis was the closest to being ready, which wasn't that unusual - for much of the Shuttle's career there were launches a month or so apart (not that there were launches monthly, but you'd get a cluster of 2-3 in a 4 month period and then nothing for 6 months). Nonetheless it was several weeks away and Columbia's life support was good for maybe a couple of weeks. There would have been significant corner-cutting to the point that losing Atlantis was a significant risk.

          Additionally, the EVA suits Columbia was carrying are not designed to be self-donned. They require help to get on. There is a major question as to whether at least two of the Columbia crew would have been physically able to get suited, into the airlock and across to Atlantis (even if it hadn't blown up on launch or suffered similar foam-strike damage).

          Getting more data from DoD assets would only have confirmed their worst suspicions - there was no possibility of in-orbit repair. It is reasonable to suggest that at least one orbiter and two crew were already dead. The question was whether to risk another orbiter and 2-3 more crew to pick up the remaining 5 astronauts.

        3. Peter2 Silver badge

          Re: It's about government control

          Shuttle's problems were at root designed in by incessant cost-cutting

          Incessant cost-cutting? A shuttle launch cost over ten times the cost of the Soyuz family of rockets the Russians came up with. There were 131 shuttle launches, with 2 losses and 963 Soyuz's, with 24 losses, which actually gives a pretty similar failure rate.

        4. Anonymous Coward
          Anonymous Coward

          Re: It's about government control

          And there, in a nutshell, is the reason why NASA will continue to fail, and others will eventually make it irrelevant except as a miniscule federal jobs program. The few spectacular successes in unmanned solar system exploration have a dwindling number of follow-on projects because the SLS continues to eat the budget. The US manned program is going to be stuck in low earth orbit for generations to come because of it.

          1. Emmeran

            Re: It's about government control

            You're dodging the fact that the ancillary research (such as RNA changes) done by NASA is what really matters at this point; commercial companies just won't invest in that.

            In the end (through a foggy, fished lens) I see NASA evolving into a regulatory agency for safety and welfare and the fact is we'll need that.

      4. Aitor 1

        Re: It's about government control

        The price of SpaceX rockets is far below previous generations: everything is cheaper, and they seem to be quite reliable.

        As for SLS vs Falcon Heavy.. how can you claim the SLS is more reliable when it hasnt been used? I would say it is unknown.. designed to be safe for passangers (or as safe as these things are), yet untested.

        If I had to sit on top of one of them, once the falcon heavy has been tested a few times, I would go on a falcon Heavy.

        Going back to price.. it is not that SpaceX is a bit cheaper. It is several times as cheap.

      5. rh587

        Re: It's about government control

        SpaceX's record on planning isn't very good. A long time ago their intention was to design a disposable booster that was so cheap to manufacture that it didn't matter that it was being thrown away every launch.

        To this end they did do some quite clever things, including the original design of their rocket engine bells. These were made by forming two bells from sheet, pressing one of them to be crinkly, fitting one inside the other and welding / brazing them together. This made all the cooling channels for the bell in only a few operations; quick and a lot cheaper than brazing miles and miles of tubing into the shape of a bell.

        Anyway, it turned out that they couldn't get the price down far enough that way. So disposability went, re-usability came in, hence their landing legs, etc.

        This is called iteration. It's why SpaceX are running a lucrative launch business and SLS isn't operational. They ran with something, realised it was sub-optimal but worked, so tweaked the design in-service whilst moving forward in incremental blocks validating the rest of the design as they went - instead of allowing the entire project to stall. This contrasts favourable with SLS which has spent over a decade trying to develop the perfect booster to replace a system we already developed in the 1960s despite having the head start of reusing major components from the Shuttle.

        Re-using Shuttle engine and solid booster designs is an excellent way to achieve this.

        Ah yes, the Shuttle. Unique amongst operational launch vehicles for having no useful launch abort that could separate astronauts from the single most complex part of the launch stack (and consequently most likely to fail - which it did, once).

        And when it comes to getting Falcon / Falcon Heavy man rated, meetings between NASA and SpaceX on this topic didn't go well; turns out you can't just claim it's reliable, you have to do all the paperwork to demonstrate that.

        And yet despite this, NASA intend to put meatbags on top of SLS on it's second launch.

        Meanwhile SpaceX has 49/51 successful F9 launches to it's name, and both the failures would have been survivable had they been carrying a Crew Dragon capsule with a launch abort mechanism.

        I know which rocket I'd strap myself on to.

      6. Anonymous Coward
        Anonymous Coward

        NASA's manned flight losses

        "NASA's manned flight loses were entirely down to things that were thought to be reliable or impossible turning out not to be so."

        You should read the Space Shuttle disaster reports. The only people who thought that the Space Shuttle was super-reliable and couldn't go catastrophically wrong in the ways that it did were some of the management at NASA.

        Richard Feynman had one NASA manager tell him that the launch failure rate for the Space Shuttle was predicted to be 1 in 100,000. NASA engineers told him they expected a launch failure rate of closer to 1 in 100.

        The engineers knew perfectly well what its vulnerabilities were, and had a pretty good idea what the real flight failure rate was likely to be.

        That's not to say that you don't need proper quality control methods to ensure reliability, but it's simply wrong to state that, for example, no-one knew about the problems with the Space Shuttle's solid fuel booster o-ring seals before the Challenger disaster. Even NASA management knew the seals were dodgy, but spun words around the problem in the hope that would make it disappear.

        And the idea that only NASA's traditional contractors can be trusted with manned space flight doesn't make sense. Engineering is engineering. If you've got good engineers working under good management, if you make reliability a prime concern, and if everyone does their job properly (including following suitable quality management procedures), you'll end up with good reliability.

        It's how come, for example, the Saturn I and the Black Knight rockets managed a perfect reliability record despite their builders not having had a vast amount of experience in the business.

        (Okay, okay, so Wernher von Braun bossed the Saturn I project and he did have a lot of experience and yes it used a lot of flight-proven hardware. But still, it was early in the space race and was trying out a new approach.)

    2. E_Nigma

      Re: It's about government control

      "I don't see the parallel development of different rockets as a problem" Different teams independently developing different rockets and not sharing the info is why Soviets failed to send the man to the Moon before the US (although the fact that the furthest advanced project got scrapped in one of the purges didn't help either).

      1. d3vy

        Re: It's about government control

        "Different teams independently developing different rockets and not sharing the info is why Soviets..."

        I cant help but agree, I know commercial interests will never allow this to happen but I cant help but think that if we all got over the "US Space Programme", "European Space Programme".. Russia/India/China etc and just collaborated we'd be well on our way to colonising the outer planets by now (Maybe a touch optimistic!)

    3. PleebSmasher
      Boffin

      Falcon Heavy's lateness never mattered

      Payloads that were to originally fly on Falcon Heavy ended up flying on Falcon 9, because Falcon 9's design evolved so much.

      It was also better to wait until Falcon 9 boosters could be vertically landed routinely, because Falcon Heavy has 3 of them and that is where most of its potential cost savings come from. Rapid reusability is also an issue: the Falcon Heavy maiden launch used Falcon 9 Block 4 boosters, but all subsequent ones will use Block 5, the "final" Falcon 9.

      Falcon Heavy is a fun launcher but it will be made completely obsolete by BFR.

  5. Anonymous Coward
    Anonymous Coward

    Speed

    Not mentioned in the article, but also quite important, is that the SLS is faster than Falcon Heavy. If you lob something towards the outer solar system with SLS, it'll get there a lot sooner. For manned flight to Mars, that matters a lot.

    Payload is not the only spec that matters.

    1. DrMordrid

      Re: Speed

      Comparing SLS, a super-heavy class, to Falcon Heavy, a heavy class, is disengenuous at best.

      By not comparing SLS to BFR, which may well fly first and lifts more, Gerst shows that the congresscritters are pulling his strings.

      BFR: 2020-2021, 150 metric tonnes to LEO

      SLS Block 1: 2020-2021, 70-80 tonnes to LEO

      SLS Block 2: 2029, 130 tonnes to LEO

    2. Black Betty

      Re: Speed

      A Holman orbit, is a Holman orbit, is a Holman orbit.

      Absent the use of a continuous thrust engine, or a ruinous waste of payload mass, the time to Mars is a fixed quantity. Particularly if you plan on stopping. The whole point of a Holman orbit is to ballistically "kiss" the destination planet's orbit while travelling at very nearly the same velocity as the planet.

      And that's the point of the multiple inner system flybys that a number of recent missions used. Each planetary pass is used steal momentum from that planet to expand smaller orbits into larger ones with a minimum expenditure of fuel, until eventually (if everyone did their sums right) the spacecraft creeps up on its destination slowly enough to chuck a u-turn around the planet and throw out the anchors.

      It doesn't matter where you're going, if you're means of travel is primarily ballistic, ie. rocketry, then no shortcut will ever get you there any faster than a significant fraction of the orbital period of your destination. The only shenanigans practical or permissible with rockets is to increase total travel time in order to reduce fuel requirements to achievable levels.

      Bigger will always let you send more to the destination, but the fuel requirements for faster travel increase exponentially. Only continuous thrust technology can break that impas.

      1. Destroy All Monsters Silver badge
        Windows

        Re: Speed

        That's a "Hohmann orbit" though.

        Absent the use of a continuous thrust engine, or a ruinous waste of payload mass, the time to Mars is a fixed quantity.

        Cranberry-shaped bollocks.

        A Hohmann orbit is optimal for minimal delta-V. Time is unimportant. Who does that except space miners lobbing completely unimportant space rocks through the system?

    3. Dave 126 Silver badge

      Re: Speed

      > SLS is faster than Falcon Heavy.

      SLS doesn't exist yet, so let's group it with the upcoming SpaceX BFR instead of the current Falcon Heavy.

    4. rh587

      Re: Speed

      Not mentioned in the article, but also quite important, is that the SLS is faster than Falcon Heavy. If you lob something towards the outer solar system with SLS, it'll get there a lot sooner. For manned flight to Mars, that matters a lot.

      Payload is not the only spec that matters.

      You're not going to be launching an inter-planetary craft in one shot anyway.

      The cramped quarters of Apollo was okay for a couple of days to the Moon and back. Not for months to Mars. A Martian ship is invariably going to be BFR-scale. If it isn't BFR, then it'll be something assembled in-orbit that gives you that much volume (and then powered by Ion Engines or similar). For manned missions it doesn't matter because you're only going to LEO or a near-Earth orbit anyway for transfer into your interplanetary vehicle.

    5. PleebSmasher
      Boffin

      This does NOT matter

      Every single one of the planned SLS launches is to the Moon, with the upcoming ones building the LOP-G space station. Not Mars or anything. There was a planned launch to send Europa Clipper to orbit Jupiter, but the Trump administration's NASA budget proposal has indicated that mission will likely be flown on a commercial launcher instead.

      By the time SLS is ready to go anywhere beyond the Moon, SpaceX's BFR will be able to send more mass faster, and even more so with in-orbit refueling.

  6. Anonymous Coward
    Anonymous Coward

    This seems logical to me. While SpaceX are doing awesome work, they still have a long way to go. When Elon sits $8bn on top of one of his rockets and launches it into space, he can argue NASA should. I don't think, sensibly, SpaceX should want this responsibility at this point.

    If it blows, who pays to build another? How long will that take? What science are we missing in the mean time? And probably of most concern to SpaceX, what damage will it do to their rep?

    1. Anonymous Coward
      Anonymous Coward

      So that's why NASA launches those 8bn on an Ariane V and no US rocket? <G>

    2. PleebSmasher
      Mushroom

      We have no data to suggest that SLS won't blow up on first launch.

      SpaceX paid its own cash to get Falcon Heavy off the ground, and successfully tested it in full view of the world. The same will happen with BFR, possibly before SLS tries to get off the ground.

  7. Pete 2 Silver badge

    Some assembly required

    ISTM whichever outfit (or government) can demonstrate a LEO rocket assembly capability will make the need to launch monolithic large payloads in a single shot, obsolete.

    We have been told that LEO is half way to anywhere in the Solar System simply because the energy needed to get the first 200km is the same as that needed to get the next few billion. So why not use a "stepping stone" approach? Costs go up dramatically as distance increases. NASA refuted the LEO is halfway ... argument by considering $$$$ cost, rather than energy / weight requirements. By that measure the Moon is 10 times more expensive than LEO.

    But if 2 LEO shots can get a Moon mission to the (energy) halfway point, then it makes the payload goals of the SLS obsolete. All they would need is a platform in low orbit to put all the parts together.

    1. Anonymous Blowhard

      Re: Some assembly required

      @Pete 2

      This was my thought too; SpaceX could concentrate on making the regular Falcon a man-rated booster for putting a small capsule into LEO. There's already a market for this with ISS missions.

      If you want to go further into space you can do an unmanned launch of your deep space vehicle on a heavy or ultra-heavy booster and then send the crew up on your Falcon capsule once you're happy that your Mars vehicle (or whatever) is up there and checked out.

      The heavy and ultra-heavy boosters are never going to be as well tested as the regular Falcons, because the market won't support the number of launches needed, so it doesn't make sense to risk crews on them when the overall cost of a modular approach will be less anyway.

      1. Julz

        Re: Some assembly required

        Hum, the market for heavier payloads to LEO or anywhere else dosn't really exist because the viable means to achieve it doesn't exist. It's a build it and they will come moment.

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