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NASA, CNES Warn SpaceX of Challenges in Flying Reusable Falcon 9 Rocket

33 points by mkempe 13y ago

angersock 13y ago
“We tried to make the engines reusable for 55 flights,” he said in Paris last month. “Look how long and how much money it took for us to do that, and we still weren't successful for all parts.” Sour grapes, much? This is why it's important to have different groups of engineers trying different things--you get a chance to pull off things previously thought impossible or prohibitive.
- acqq 13y ago
  Let's wait and see how it will actually work. The guys who designed Space Shuttle also expected much more reusability than what they managed to achieve. There are serious physical limits that you just can't be even aware of until you actually try.
  - aleyan 13y ago
    That makes sense. There is also a question of will though. IANARS (I am not a rocket scientist), but it seems to me a lot of political investment behind rockets in USA and USSR was military in origin. This meant the rockets and rocket engines they spent most effort on was for single delivery of a warhead with no chance of reuse. Civilian rocketry was just a byproduct of efforts to deliver the bomb. We see this with Russian commercial satellite launches using repurposed ICBMs. If military didn't care about the reuse, the civilian programs would have had to work on it on their own. I believe that with enough will and advances in technology, engineering problems for reusable rocket engines could be overcome.
    - simonh 13y ago
      Yep, the whole industry, including payload manufacturing and operational economics, is geared around super-high launch costs. That means you spare no expense making sure your payload is absolutely perfect. High costs of launch breed high costs for payload design and manufacture, which means you need to guarantee a high chance of getting your precious payload to orbit, which means you want a pristine rocket to carry it for the best chance of a successful launch. It's a vicious cycle, driving up quality requirements and costs at every point in the cycle. SpaceX is intending to break that cycle. If launch costs are low, then you can afford to put cheap payloads into orbit. If the payload fails, just launch another one. If the best chance of a successful launch matters a lot to you, pay a premium to launch on a virgin booster. However re-usability of the first stage is only going to get them so far. If half the total cost of a launch (pure guess) is in the booster hardware, and they get just 10 launches out of each one, then the total cost per launch will be cut to close to half of what it is now. That's great, amazing even, but it's not 10x cheaper and certainly not 100x. To get down even close to 10x cheaper they need to recover the second stage as well.
    - InclinedPlane 13y ago
      A huge amount of investment in rocketry in the US was very much civilian. Easily a quarter of a trillion dollars, and that's excluding Apollo. However, that money was not well spent. I could go into the topic in depth but suffice it to say that politics and bureaucracy have had a stranglehold on NASA manned spaceflight and launch vehicle development since the beginning, and that has had a very negative impact on progress and capabilities. In contrast, unmanned spaceflight at NASA has been, comparatively, much better managed. And there you see a much clearer and sharper continual increase in capabilities, ambition, missions, and so on over time. The missions that would have been acceptable in the 1970s (planetary flybys, for example) would today not return enough science to be justified. Today we have multi-year rover missions on Mars, and we have spacecraft which rendezvous and orbit multiple asteroids using ion engines. Meanwhile, in manned spaceflight we haven't been out of Earth orbit since the early '70s.
  - InclinedPlane 13y ago
    The Space Shuttle is an enormously complicated system. The Orbiter itself is a marriage of a crew transfer spacecraft, a space station, a cargo tug, a cargo carrier, and a goddamned airplane. Worse yet, it used one of the most finicky propellants around, LOX/LH2. Then you shoehorn that beast into a weirdly designed partially expendable heavy lift launcher with SRBs and a drop tank and it's no wonder you end up with a system that is difficult to operate inexpensively. Meanwhile, the Falcon 9 stage is primarily just engines, tanks, and frame, with a sprinkling of avionics and RCS plus landing legs for the reusable version. The idea that a system so monstrously simple in comparison to the Shuttle could possibly have the same levels of difficulty of reusability is either extraordinarily naive or propaganda.
    - acqq 13y ago
      No, it's not propaganda, if you'd care to search you'd find enough material yourself. They first planned to reuse the booster engines and just produce new tanks. They discovered that the engines weren't reusable as much as they hoped only once they made actual launches. The rocket engines function a bit differently than the jet engines, all the problems are bigger by the order of magnitude. The engines have to sustain immense temperature extremes, which in turn change the characteristics of the parts. What's usable on the first launch can be just a trash the next time. Until you have enough launches, you just don't know how reusable equipment you have.
      - dba7dba 13y ago
        True. But falcon 9 is far less complicated than shuttle so the chance of having more reusable equipment should be higher.
        acqq 13y ago
        I'm giving the example not of the whole Shuttle (complex) but just the booster engines for Shuttle (also simple). Designed to be very reusable, discovered not to be only after the real launches. That's how it works. Before you have the actual launch statistics, you can appear much smarter than you are actually. Everything is easy as long as it's just a theory. To compare, let's see what SpaceX is actually doing: The last, second attempt to recover a booster of Falcon 9 was: http://aviationweek.com/space/spacex-plans-multiple-reusable-booster-tests http://aviationweek.com/space/spacex-plans-multiple-reusable... "While SpaceX remains coy about the exact fate of the modified Falcon 9 first stage, the overall results appear to be encouraging despite the apparent breakup of the booster after it landed in heavy seas." Previous attempt: "The latest flight test follows an unsuccessful recovery attempt on Sept. 29, 2013, when the first upgraded Falcon 9 v1.1 was launched from Vandenberg AFB, Calif. Although three of its nine Merlin 1D engines fired to slow the initial descent ahead of a single engine firing for final braking, the vehicle’s spinning motion could not be controlled. As a result of aerodynamic torque, the fuel centrifuged inside the tank, flaming out the engine and sending the stage crashing into the sea."
  - mikeash 13y ago
    The Space Shuttle was a political football whose design was dictated by the whims of Congress and the meddling of the military first, and by engineering second. The Shuttle was required to be reusable as a political goal. However, it was not given the funding it needed to actually accomplish it in any reasonable fashion. The Air Force put some tough requirements on it, such as the requirement for enough cross-range capability when landing to be able to launch into a polar orbit from Vandenberg, deploy a satellite, and land back one orbit later. This is purely a wartime requirement. No peacetime mission needs this. This required much bigger wings (and thus much more weight), even though the Shuttle never once launched out of Vandenberg, let alone on one of these crazy single-orbit missions. Politics screwed up other stuff too. The solid rocket boosters, for example, were manufactured on the other side of the country, largely because of Congressional pork. The long and difficult transport process required the boosters to be built segmented, and that design directly lead to the loss oF Challenger. Similarly, budget constraints dictated the cheaper SRB-plus-external-tank design rather than a more sophisticated and more reusable (and more expensive) reusable booster. This design directly lead to the loss of Columbia. The net result was that the Shuttle had a very narrow engineering margin. The SSMEs are engineering marvels in terms of how light they are and how much power they put out. But putting out a lot of power for little weight is a really bad plan for something you want to reuse. Reusability means robustness, and robustness means extra weight and less power. The Shuttle is what you get when you say, "How much will it cost for a reusable launch system? $10 billion? Too much, we'll give you $5 billion." (Numbers in the ballpark but mostly made up for illustration.) On the other hand, the Falcon 9R is what you get when a for-profit space launch company wants to make more money. It's not a prestige project, it's not a political project, it's not a military project dictated by thoughts of all-out war with the USSR, it's not subject to Presidential grandstanding or Congressional pork. It's just a bunch of smart people thinking of ways to save their customers money and turn a better profit while doing it. The Shuttle was an extremely ambitious design that did everything differently. Ultimately, everything was too ambitious to be reusable. Falcon 9R, on the other hand, is deeply unambitious. The rocket is a pretty standard design. They don't even try to use liquid hydrogen for any stage, even though it's theoretically more efficient, instead favoring easier-to-handle kerosene. Their rocket engines are high performance but not on the bleeding edge. And when they decided to go for reusability, instead of building a whole new system with wings and ceramic tiles and all sorts of other extreme innovations, they just said, let's slap some legs on the first stage and give it some extra fuel. It's a completely different approach that pretty much only shares the word "reusable". I don't think the Shuttle really has many lessons to offer when evaluating the potential of Falcon 9R.
- Shivetya 13y ago
  I am going to assume the engines themselves are the most expensive part and would require reconditioning regardless of landings on water or earth, why not just make that part recoverable? Parachute it back? Can the method used by Scaled Composites, jet lifting a rocket to higher altitude, be employed as a better solution? Why not rocket power the plane portion and go for even higher based launch? Granted some cargo would be lost to weight for control surfaces and wings but recovery should be simpler, a glide path cannot be as hard as landing upright.
  - cecilpl 13y ago
    > Why not rocket power the plane portion and go for even higher based launch? That's what the first stage of the Falcon 9 is - a rocket powered boost to enable the second stage to launch from a high altitude.
  - VLM 13y ago
    "why not just make that part recoverable? Parachute it back?" Terminal velocity in atmosphere is proportional to density and engines are surprisingly dense so you'd need to pack a simply enormous parachute. On the other hand, that big mostly empty tank will slow down the engine for you at very little cost, and its nice to reuse it anyway. At the terminal area like 500 feet off the ground you could eject the engines and let the tanks explode but thats messy and bad PR and something you haven't added can't fail, so no parachute means no parachute failures, and you'd already navigated under power to within 500 feet of landing, so its simple, cheaper, more reliable, and much safer to just land under power.
  - Crito 13y ago
    SpaceX has tried to parachute back several first stages, without success. Parachutes for something that heavy and going that fast are very heavy and prone to failure. They also limit you to dropping it in the drink; avoiding that is key to the success of a reusable rocket.
- VLM 13y ago
  SSME vacuum ISP 452 seconds. Beyond the ability of humans to manufacture at design time. This had a predictable impact on construction cost and delivery date. Beyond the ability of humans to make reusable for a decade after deployment. Eventually turned into one hell of a monster legendary engine, a few decades later. Nothing wrong with an engine development program, but the SSME was ridiculous. Merlin family vacuum ISP a sedate 311 seconds. COTS and evolutionary based on existing engineering practice. Designed for low cost and reliability, not utter extremes of high performance. (edited to correct, not COTS. Kept thinking they adapted a RD series design at the start, but I checked and they didn't. Same general story though, lower Isp and lower chamber pressure and very conventional pintle injector design etc its good engineering aka very boring, all their engine design competitors are far more competitive, which is dumb because fuel and tanks are cheap, engine development isn't) Its very much like comparing the long term reliability of a 2024 specs F1 series racing engine none the less manufactured today in 2014 (or at least they did their best), against the engine in my new Toyota that's in it's 10th mfgr year and is pretty much bulletproof.
  - hga 13y ago
    Bingo. I've heard long ago that the SSMEs were cutting edge, "race car" (exactly those words) engines, and that's why they required a complete rebuild after each mission. In another subthread, someone commented on the Space Shuttle being designed for reuse. Well, sort of, especially at the beginning, at the top, but various ambitions that weren't strictly needed (e.g. the SSMEs, single polar orbit missions) and insufficient budget (turning the reusable first stage every one envisioned before into the kludge of the throwaway tank and massively dangerous SRBs) meant by the time it launched it had no hope whatsoever of meeting those goals. Add bogus safety calculations, and it was never going to be a "space truck". Space X, on the other hand, seems to understand what this is all about. And unlike NASA isn't burdened by implicit requirements like employing lots of people at the maximum number of sites, or the explicit mission of boosting the South's technical prowess.
  - MrMeker 13y ago
    It seemed broken that this comment was at the bottom, so I upvoted it.
- danielweber 13y ago
  I think SpaceX is awesome, but NASA's engineers aren't bozos or incompetent. The entire space shuttle history is one of competing and conflicting political ambitions all being shoved onto it, and that's why the whole thing is hard for any engineer to do right. That said, I think it's pretty obvious that even after SpaceX successfully lands a Stage 1, they are going to do lots of simulated and real-world testing before using one for any customer cargo. I can see the day in the future, though, when a first stage that has been launched 2 or 3 times is considered safer than a first stage that has been launched 0 times. I anticipate a bathtub curve of failures.
  - InclinedPlane 13y ago
    NASA's engineers may not be bozos but they aren't authorities on what's possible either. And they have weaknesses just like any professionals. They especially have a weakness to imagine that something they have failed at achieving is actually a lot more difficult than it truly is. Nobody wants to imagine that they are incompetent or that they've missed something so obvious that they turned something that should have easy into something incredibly difficult. But it seems increasingly obvious that this is precisely what NASA has done.
  - nickff 13y ago
    The most interesting part of SpaceX's plan is that even if the subsequent launches are riskier than the first, it will still be worth doing for the customers, as the average launch price will be much cheaper. Launch costs have come to dominate satellite non-recurring expenditures, so it will would be worth building a couple of extra satellites for every constellation, and knowing that some may be lost on launch. Some buyers who are risk averse may opt to only use first-launch rockets, while others who are cost sensitive will buy rockets on their last legs. This could revolutionize the entire launch market, and enable many more low-cost satellites to be launched.
- josefresco 13y ago
  Having taken an interest in this topic, and having watched the Sentate hearing (among others) where the ULA was asked to defend/validate it's model I find there's "sour grapes" everywhere among the incumbent players. You could easily swap the quoted line with this (related to Tesla) and it would still make sense: "We tried to make an electric car before," ... "Look how long and how much money it took for us to do that, and we still weren't successful for all parts."
- BrandonMarc 12y ago
  "impossible" ... This reminds me of a story Robert Cringely tells of Bill Gates. It seems mister Gates knew a certain thing was impossible to do, so he didn't try ... and lost million$ and market share when his competitor went and did it anyway. Here's the story: This business of taking software written for the 8086 processor and porting it to the 80286 normally required completely rewriting the software by hand, often taking years of painstaking effort. It wasn’t just a matter of recompiling the software, of having a machine do the translation, because Microsoft staunchly maintained that there was no way to recompile 8086 code to run on an 80286. Bill Gates swore that such a recompile was impossible. But Drew Major of Superset didn’t know what Bill Gates knew, and so he figured out a way to recompile 8086 code to run on an 80286. What should have taken months or years of labor was finished in a week, and Novell had won the networking war. Six years and more than $100 million later, Microsoft finally admitted defeat. http://www.cringely.com/2013/03/24/accidental-empires-chapter-14-counter-reformation/ http://www.cringely.com/2013/03/24/accidental-empires-chapte... Accidental Empires is a good book.
gatehouse 13y ago
I'm not sure that landing is more dangerous than takeoff. It's true that the thing is pointed towards the earth, but on the other hand there is a lot less fuel to explode.
- ericcumbee 13y ago
  The problem is that on launch the rocket is moving away from inhabited areas and out toward uninhabited areas during launch. On Landing it's going towards more densely populated areas. I wonder if maybe the solution is to land them on some uninhabited island, like the one the USAF targets ICBMs with dummy warheads on it from time to time.
  - Crito 13y ago
    From what I have heard, the first stage will come in aimed away at the landing, or anything else, and then perform the divert maneuver that they've been testing with Grasshopper/F9R-Dev to put itself over the landing site at the last moment. That way if anything goes wrong before the last few seconds, the rocket won't fall where it was suppose to land. They are definitely planning on doing boost-back to the general area of the launch site though, not aiming for a target down-range. The launch this weekend will have them bringing the stage back closer to land than the previous attempt.
  - deleted 13y ago
    [deleted]
lfuller 13y ago
"We'd pick them out of the ocean, but we spent a lot of time cleaning those things up when we got them back" And there's the rub. SpaceX is working on having reusable components land on solid ground.
- icegreentea 13y ago
  That quote is respect to the Shuttle Solid Rocket Booster - a part completely incomparable to the Falcon. It's really a throw away line about establishing an absolutely silly baseline. The meat of the 'argument' (and really, I don't believe it's an argument) is that the Shuttle Main Engines (the ones mounted on the tail of the Shuttle, the ones that land like a plane) had similar expectations of reusability, and ended up being absolutely terrible at reusablility. That's the point to address, not the throw away line.
  - msandford 13y ago
    Right but they were awful because they were built and tested and qualified top-down, not bottom up. Feynman wrote about this idiocy at length: http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Appendix-F.txt http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/roger...
    - api 13y ago
      I also wonder about the use of hydrogen and how this impacted reusability. From what I've read hydrogen causes things like metal embrittlement, which is why SpaceX is completely avoiding it despite the higher specific impulse it yields.
      - InclinedPlane 13y ago
        LH2 is also super cryogenic. LOX and even liquid methane have boiling points higher than LN2. You can build launchers with them without even bothering to insulate the tanks, because the boiloff is so marginal over the duration of the launch. Whereas LH2 absolutely requires a lot of insulation, because it needs to be much, much colder. Worse yet, because of the super low density of LH2 you can't afford even a small amount of boiloff because that hurts your mass fraction immensely, and if you have a LOX/LH2 vehicle you've probably scraped and scrabbled for what meager mass fraction you've managed to achieve (through advanced alloys and so forth). One particular consequence of the use of LH2 with the Shuttle was that it resulted in an ice covered and foam insulated enormous external tank cheek-by-jowl with the delicate TPS coated underbelly of the orbiter during launch, as the vehicle rammed through the air at transonic then supersonic then hypersonic speeds. Another consequence of the LH2 choice for the Shuttle is that it didn't have enough thrust at sea level to get off the pad, so it needed high-thrust, low-cost boosters as a 0th stage. Solid rockets being the obvious go-to solution, those got used. In a very real way the choice to use LH2 resulted not just in much of the cost and complexity of the Shuttle system but also the death of 2 crews and the loss of 2 orbiters.
InclinedPlane 13y ago
They know nothing about reusability. Not even NASA has operated a truly reusable vehicle, the "reusability" of Shuttle was a joke (it still cost >$1 billion per flight) and they made every mistake possible when designing the vehicle. In contrast, Falcon 9 is an enormously simple launcher and reusability should be not only fairly straightforward but also advantageous. Moreover, because reusability of the F9 will actually save money (as opposed to the Shuttle where it required a massive ongoing operational cost) it will allow more money for ongoing development of improved vehicles (which SpaceX is already working on). Additionally, SpaceX isn't dumb, they've already tested running their engines through multiple cycles on test stands, they know the issues they'll run into and they have a reasonable idea how long they can expect to use them (spoilers: lots). And SpaceX has been operating reusable rockets over the course of several flights in the form of the the Grasshopper and F-9R-Dev vehicles which they've used for test flights.
- tachyonbeam 13y ago
  Honestly, their criticism sounds like the kind of thing any jealous nay sayer would say. They're trying to make it sound like an honest warning, but in reality, they're just afraid of having their crown stolen. They're basically telling SpaceX that their new approach has unforeseen risks. It's never been done before, hence it's risky, and it could well fail, it shouldn't even be tried. They're saying the NASA people had a working model for decades, and hence people should trust NASA's expertise more, not the new guy taking big risks trying new things. In reality, they can see that SpaceX knows what they're doing, and NASA has been falling behind for a long time, but that's really hard for NASA to accept. Still makes me sad to see this kind of attitude. Risk taking is necessary for innovation, and calculated risks often pay out big time, but the establishment is still always too afraid to take the said risks... And then when somebody else is there to take those risks, they try to discourage them.
  - InclinedPlane 13y ago
    More or less. Here's the thing, SpaceX is almost certainly going to demonstrate partial launch vehicle reusability within the next year. And they're going to make it look easy. What's more, for the most part it will be easy. The damning bit is that what SpaceX ends up doing will be the sort of thing that could have been done back in the '80s or maybe even the '70s. But nobody had the right combination of pragmatism and vision to make it happen. But they could have, and there were bread crumbs all along the way. So why didn't they? A lot of it ultimately comes down to a few factors. Group think and bureaucracy. And fads. Yup, fads. One problem that orbital aerospace has been constantly afflicted with is the coolness factor problem. When pushing new projects it can be difficult to do so unless there is some sort of coolness factor, some way in which the new project is demonstrably more advanced than previous generation efforts. This is anathema to actual progress because most progress comes from copying, perfecting, and incremental innovation. The coolness factor is how we ended up with Shuttle (so cool), and X-33/VentureStar (much, much cooler). But look at the Falcon 9, it's just a 2 stage LOX/Kerosene booster, they've been building those since the '50s/'60s, it's the definition of uncool. But what it lacks in coolness it more than makes up for in usefulness. In terms of fads you can look to the Hydrogen rocket fad that still has a grip on a lot of engineers. LOX/LH2 undoubtedly has a very high Isp, and Isp is supremely important in the rocket equation. But it's not everything, and LH2 has a crapload of very serious downsides when it comes to using it in rocketry, many of which add significant cost to the system. The Hydrogen fad is why the Shuttle had SRBs (because the SSMEs couldn't generate enough thrust on their own to get off the pad) and thus is partially responsible for the Challenger disaster. It's also responsible for the Delta IV, which is an extremely expensive launcher. But back to breadcrumbs. They were there. In the early '90s the DC-X program demonstrated vertical takeoff/vertical landing was a feasible technology, and it did so using LOX/LH2 even. But the program was largely ignored because NASA was too dumb to see the promise of a reusable stage, since it wasn't cool enough relative to the idea of an SSTO RLV (in the same year as the last flight of the DC-X NASA got the X-33 program rolling). If NASA was just a little bit smarter and more practical it would have been easy to see the promise of the DC-X, easy to see the practicality of partial reusability, and easy to see the advantages of simpler launchers. But they didn't. Instead they pursued cool idea after cool idea, dumping around a billion dollars into X-33 alone. And when their overly ambitious cool ideas didn't pan out they ended up with nothing. And it was only through the comparative pragmatism of the defense department and the EELV program (which developed a couple boring 2-stage launchers) that the US had any reasonable launch capability whatsoever after the Shuttle program ended. Now it will be through the comparatively superior pragmatism (not to diminish the genius of SpaceX) that we'll end up with even greater launch capability and unprecedented reusability.
SeanLuke 13y ago
> Christophe Bonnal of the launcher directorate at French space agency CNES, agrees. “If you reuse, you stop producing, depending on the level of reusability,” he says. “So you end up with a permanent prototype, and to keep costs down you need to have a high rate of production.” I am not a rocket scientist. So someone please explain to me why this quote isn't the single stupidest thing I've read all day.
- debt 13y ago
  Haha, I know I should just upvote but this really made me chuckle pretty hard.
- anmol 13y ago
  With any advanced technology product, production volume plays a big role in making the underlying tech commodity and gradually dropping price per unit. F22's would be a lot cheaper to make (than today) if everyone had one in their backyard, like a Honda Civic.
  - ithought 13y ago
    The cost of the F22 would go down if we just crashed every one on its first flight.
- viraptor 13y ago
  I think what he means (using a software library analogy): if you have a reusable component that is not worked on but satisfies your needs now, you're going to work around all problems and implement hacks to keep using the reusable component, instead of improving it - improving/maintaining that component could cost you another development team. You get technical debt / bitrot instead. If they keep component X too long, they'll need to reimplement / rebuild X from scratch in a few years when the original factory/production line doesn't exist anymore. This would require a lot of up-front cost that may be higher than just producing a new element of that type for every launch. I don't think the message was completely negative though: "depending on the level of reusability" sounds more like "this is hard, but if you pull it off with cost of restarting production << cost of reusability over N years, that's an achievement" Edit: many words
fredgrott 13y ago
shoud we remind NASA and CENS that in the 1980s USSR had a shuttle launched by remote control and land under the same computer control..
api 13y ago
Tangential thought: It really seems to me that only companies with the "California tech startup mentality" (whether they're in Cali or not) can actually do anything today. I'm starting to refer to the rest of the economy as the "legacy economy," "legacy industry," etc. I understand some of the reasons: bottom-up engineer-led engineering teams, lean operations, little or no bureaucracy compared to large older institutions, etc. But there seems to be something else too, some kind of difficult to quantify attitude or mentality. I get it, but I find it hard to describe except to say it's about believing in the future, believing that things are actually possible. Everyone else everywhere else seems to be looking backward and thinking of all the reasons things can't be done. Like this, for example. "Here, we're NASA, and here's why it can't be done." The NASA of the 50s and the 60s is rolling in its grave! Legacy economy indeed. Disrupt everything. Ditch it all and start over.
- InclinedPlane 13y ago
  Indeed. There are folks who see disruption as valuable and those who see it is as risky, dangerous. As to the NASA of the 1960s, that was a NASA who developed 4 different manned spacecraft in a 10 year period (Mercury, Gemini, Apollo CM & Apollo LM) and flew them on 4 different rockets (Atlas, Titan, Saturn I, Saturn V). That's the sort of activity that looks similar to what SpaceX is doing today and very dissimilar to what NASA is doing today (sinking billions per year into masses of bureaucratic BS and very little hardware).
  - hga 13y ago
    Five different rockets! The first suborbital Mercury flights used Redstones, V-2 descendants that used alcohol and LOX. Followed by the Atlas that used kerosene and LOX like Space X, the Titan which used fuels that could be stored in the rocket for long terms, making it a practical ICBM (taken out of service in the mid-80s). All those were adopted from military missiles, and were followed by the purpose built Saturn I and V, and both of their first stages also used kerosene and LOX. Am I seeing a pattern here ^_^? (Quibbles: the "kerosene" used in rockets is actually highly refined stuff: https://en.wikipedia.org/wiki/RP-1 https://en.wikipedia.org/wiki/RP-1 and the Saturn upper stages used liquid hydrogen and LOX.)
voidlogic 13y ago
There have been very few reusable delivery systems (1? sorta?). That is too low of a sample size to draw conclusions. SpaceX has shown itself to be much more efficient than NASA and NASA's usual vendors, who is to say this will not build a better reusable delivery system? After all the last one was designed 40+ years ago by a very bureaucratic/political organization. Not to mention that Space uses Kerosene rather than Hydrogen for materials related reasons. Also, while some comparisons to the shuttle's main engine are warranted, refurb costs of the shuttle's solid boosters will not be comparable as they landed in the ocean rather than on dry land. Ocean water is nasty stuff for hitech equipment.

33 points by mkempe 13y ago

“We tried to make the engines reusable for 55 flights,” he said in Paris last month. “Look how long and how much money it took for us to do that, and we still weren't successful for all parts.” Sour grapes, much? This is why it's important to have different groups of engineers trying different things--you get a chance to pull off things previously thought impossible or prohibitive.

acqq 13y ago
Let's wait and see how it will actually work. The guys who designed Space Shuttle also expected much more reusability than what they managed to achieve. There are serious physical limits that you just can't be even aware of until you actually try.
- aleyan 13y ago
  That makes sense. There is also a question of will though. IANARS (I am not a rocket scientist), but it seems to me a lot of political investment behind rockets in USA and USSR was military in origin. This meant the rockets and rocket engines they spent most effort on was for single delivery of a warhead with no chance of reuse. Civilian rocketry was just a byproduct of efforts to deliver the bomb. We see this with Russian commercial satellite launches using repurposed ICBMs. If military didn't care about the reuse, the civilian programs would have had to work on it on their own. I believe that with enough will and advances in technology, engineering problems for reusable rocket engines could be overcome.
  - simonh 13y ago
    Yep, the whole industry, including payload manufacturing and operational economics, is geared around super-high launch costs. That means you spare no expense making sure your payload is absolutely perfect. High costs of launch breed high costs for payload design and manufacture, which means you need to guarantee a high chance of getting your precious payload to orbit, which means you want a pristine rocket to carry it for the best chance of a successful launch. It's a vicious cycle, driving up quality requirements and costs at every point in the cycle. SpaceX is intending to break that cycle. If launch costs are low, then you can afford to put cheap payloads into orbit. If the payload fails, just launch another one. If the best chance of a successful launch matters a lot to you, pay a premium to launch on a virgin booster. However re-usability of the first stage is only going to get them so far. If half the total cost of a launch (pure guess) is in the booster hardware, and they get just 10 launches out of each one, then the total cost per launch will be cut to close to half of what it is now. That's great, amazing even, but it's not 10x cheaper and certainly not 100x. To get down even close to 10x cheaper they need to recover the second stage as well.
  - InclinedPlane 13y ago
    A huge amount of investment in rocketry in the US was very much civilian. Easily a quarter of a trillion dollars, and that's excluding Apollo. However, that money was not well spent. I could go into the topic in depth but suffice it to say that politics and bureaucracy have had a stranglehold on NASA manned spaceflight and launch vehicle development since the beginning, and that has had a very negative impact on progress and capabilities. In contrast, unmanned spaceflight at NASA has been, comparatively, much better managed. And there you see a much clearer and sharper continual increase in capabilities, ambition, missions, and so on over time. The missions that would have been acceptable in the 1970s (planetary flybys, for example) would today not return enough science to be justified. Today we have multi-year rover missions on Mars, and we have spacecraft which rendezvous and orbit multiple asteroids using ion engines. Meanwhile, in manned spaceflight we haven't been out of Earth orbit since the early '70s.
- InclinedPlane 13y ago
  The Space Shuttle is an enormously complicated system. The Orbiter itself is a marriage of a crew transfer spacecraft, a space station, a cargo tug, a cargo carrier, and a goddamned airplane. Worse yet, it used one of the most finicky propellants around, LOX/LH2. Then you shoehorn that beast into a weirdly designed partially expendable heavy lift launcher with SRBs and a drop tank and it's no wonder you end up with a system that is difficult to operate inexpensively. Meanwhile, the Falcon 9 stage is primarily just engines, tanks, and frame, with a sprinkling of avionics and RCS plus landing legs for the reusable version. The idea that a system so monstrously simple in comparison to the Shuttle could possibly have the same levels of difficulty of reusability is either extraordinarily naive or propaganda.
  - acqq 13y ago
    No, it's not propaganda, if you'd care to search you'd find enough material yourself. They first planned to reuse the booster engines and just produce new tanks. They discovered that the engines weren't reusable as much as they hoped only once they made actual launches. The rocket engines function a bit differently than the jet engines, all the problems are bigger by the order of magnitude. The engines have to sustain immense temperature extremes, which in turn change the characteristics of the parts. What's usable on the first launch can be just a trash the next time. Until you have enough launches, you just don't know how reusable equipment you have.
    - dba7dba 13y ago
      True. But falcon 9 is far less complicated than shuttle so the chance of having more reusable equipment should be higher.
      - acqq 13y ago
        I'm giving the example not of the whole Shuttle (complex) but just the booster engines for Shuttle (also simple). Designed to be very reusable, discovered not to be only after the real launches. That's how it works. Before you have the actual launch statistics, you can appear much smarter than you are actually. Everything is easy as long as it's just a theory. To compare, let's see what SpaceX is actually doing: The last, second attempt to recover a booster of Falcon 9 was: http://aviationweek.com/space/spacex-plans-multiple-reusable-booster-tests http://aviationweek.com/space/spacex-plans-multiple-reusable... "While SpaceX remains coy about the exact fate of the modified Falcon 9 first stage, the overall results appear to be encouraging despite the apparent breakup of the booster after it landed in heavy seas." Previous attempt: "The latest flight test follows an unsuccessful recovery attempt on Sept. 29, 2013, when the first upgraded Falcon 9 v1.1 was launched from Vandenberg AFB, Calif. Although three of its nine Merlin 1D engines fired to slow the initial descent ahead of a single engine firing for final braking, the vehicle’s spinning motion could not be controlled. As a result of aerodynamic torque, the fuel centrifuged inside the tank, flaming out the engine and sending the stage crashing into the sea."
- mikeash 13y ago
  The Space Shuttle was a political football whose design was dictated by the whims of Congress and the meddling of the military first, and by engineering second. The Shuttle was required to be reusable as a political goal. However, it was not given the funding it needed to actually accomplish it in any reasonable fashion. The Air Force put some tough requirements on it, such as the requirement for enough cross-range capability when landing to be able to launch into a polar orbit from Vandenberg, deploy a satellite, and land back one orbit later. This is purely a wartime requirement. No peacetime mission needs this. This required much bigger wings (and thus much more weight), even though the Shuttle never once launched out of Vandenberg, let alone on one of these crazy single-orbit missions. Politics screwed up other stuff too. The solid rocket boosters, for example, were manufactured on the other side of the country, largely because of Congressional pork. The long and difficult transport process required the boosters to be built segmented, and that design directly lead to the loss oF Challenger. Similarly, budget constraints dictated the cheaper SRB-plus-external-tank design rather than a more sophisticated and more reusable (and more expensive) reusable booster. This design directly lead to the loss of Columbia. The net result was that the Shuttle had a very narrow engineering margin. The SSMEs are engineering marvels in terms of how light they are and how much power they put out. But putting out a lot of power for little weight is a really bad plan for something you want to reuse. Reusability means robustness, and robustness means extra weight and less power. The Shuttle is what you get when you say, "How much will it cost for a reusable launch system? $10 billion? Too much, we'll give you $5 billion." (Numbers in the ballpark but mostly made up for illustration.) On the other hand, the Falcon 9R is what you get when a for-profit space launch company wants to make more money. It's not a prestige project, it's not a political project, it's not a military project dictated by thoughts of all-out war with the USSR, it's not subject to Presidential grandstanding or Congressional pork. It's just a bunch of smart people thinking of ways to save their customers money and turn a better profit while doing it. The Shuttle was an extremely ambitious design that did everything differently. Ultimately, everything was too ambitious to be reusable. Falcon 9R, on the other hand, is deeply unambitious. The rocket is a pretty standard design. They don't even try to use liquid hydrogen for any stage, even though it's theoretically more efficient, instead favoring easier-to-handle kerosene. Their rocket engines are high performance but not on the bleeding edge. And when they decided to go for reusability, instead of building a whole new system with wings and ceramic tiles and all sorts of other extreme innovations, they just said, let's slap some legs on the first stage and give it some extra fuel. It's a completely different approach that pretty much only shares the word "reusable". I don't think the Shuttle really has many lessons to offer when evaluating the potential of Falcon 9R.
Shivetya 13y ago
I am going to assume the engines themselves are the most expensive part and would require reconditioning regardless of landings on water or earth, why not just make that part recoverable? Parachute it back? Can the method used by Scaled Composites, jet lifting a rocket to higher altitude, be employed as a better solution? Why not rocket power the plane portion and go for even higher based launch? Granted some cargo would be lost to weight for control surfaces and wings but recovery should be simpler, a glide path cannot be as hard as landing upright.
- cecilpl 13y ago
  > Why not rocket power the plane portion and go for even higher based launch? That's what the first stage of the Falcon 9 is - a rocket powered boost to enable the second stage to launch from a high altitude.
- VLM 13y ago
  "why not just make that part recoverable? Parachute it back?" Terminal velocity in atmosphere is proportional to density and engines are surprisingly dense so you'd need to pack a simply enormous parachute. On the other hand, that big mostly empty tank will slow down the engine for you at very little cost, and its nice to reuse it anyway. At the terminal area like 500 feet off the ground you could eject the engines and let the tanks explode but thats messy and bad PR and something you haven't added can't fail, so no parachute means no parachute failures, and you'd already navigated under power to within 500 feet of landing, so its simple, cheaper, more reliable, and much safer to just land under power.
- Crito 13y ago
  SpaceX has tried to parachute back several first stages, without success. Parachutes for something that heavy and going that fast are very heavy and prone to failure. They also limit you to dropping it in the drink; avoiding that is key to the success of a reusable rocket.
VLM 13y ago
SSME vacuum ISP 452 seconds. Beyond the ability of humans to manufacture at design time. This had a predictable impact on construction cost and delivery date. Beyond the ability of humans to make reusable for a decade after deployment. Eventually turned into one hell of a monster legendary engine, a few decades later. Nothing wrong with an engine development program, but the SSME was ridiculous. Merlin family vacuum ISP a sedate 311 seconds. COTS and evolutionary based on existing engineering practice. Designed for low cost and reliability, not utter extremes of high performance. (edited to correct, not COTS. Kept thinking they adapted a RD series design at the start, but I checked and they didn't. Same general story though, lower Isp and lower chamber pressure and very conventional pintle injector design etc its good engineering aka very boring, all their engine design competitors are far more competitive, which is dumb because fuel and tanks are cheap, engine development isn't) Its very much like comparing the long term reliability of a 2024 specs F1 series racing engine none the less manufactured today in 2014 (or at least they did their best), against the engine in my new Toyota that's in it's 10th mfgr year and is pretty much bulletproof.
- hga 13y ago
  Bingo. I've heard long ago that the SSMEs were cutting edge, "race car" (exactly those words) engines, and that's why they required a complete rebuild after each mission. In another subthread, someone commented on the Space Shuttle being designed for reuse. Well, sort of, especially at the beginning, at the top, but various ambitions that weren't strictly needed (e.g. the SSMEs, single polar orbit missions) and insufficient budget (turning the reusable first stage every one envisioned before into the kludge of the throwaway tank and massively dangerous SRBs) meant by the time it launched it had no hope whatsoever of meeting those goals. Add bogus safety calculations, and it was never going to be a "space truck". Space X, on the other hand, seems to understand what this is all about. And unlike NASA isn't burdened by implicit requirements like employing lots of people at the maximum number of sites, or the explicit mission of boosting the South's technical prowess.
- MrMeker 13y ago
  It seemed broken that this comment was at the bottom, so I upvoted it.
danielweber 13y ago
I think SpaceX is awesome, but NASA's engineers aren't bozos or incompetent. The entire space shuttle history is one of competing and conflicting political ambitions all being shoved onto it, and that's why the whole thing is hard for any engineer to do right. That said, I think it's pretty obvious that even after SpaceX successfully lands a Stage 1, they are going to do lots of simulated and real-world testing before using one for any customer cargo. I can see the day in the future, though, when a first stage that has been launched 2 or 3 times is considered safer than a first stage that has been launched 0 times. I anticipate a bathtub curve of failures.
- InclinedPlane 13y ago
  NASA's engineers may not be bozos but they aren't authorities on what's possible either. And they have weaknesses just like any professionals. They especially have a weakness to imagine that something they have failed at achieving is actually a lot more difficult than it truly is. Nobody wants to imagine that they are incompetent or that they've missed something so obvious that they turned something that should have easy into something incredibly difficult. But it seems increasingly obvious that this is precisely what NASA has done.
- nickff 13y ago
  The most interesting part of SpaceX's plan is that even if the subsequent launches are riskier than the first, it will still be worth doing for the customers, as the average launch price will be much cheaper. Launch costs have come to dominate satellite non-recurring expenditures, so it will would be worth building a couple of extra satellites for every constellation, and knowing that some may be lost on launch. Some buyers who are risk averse may opt to only use first-launch rockets, while others who are cost sensitive will buy rockets on their last legs. This could revolutionize the entire launch market, and enable many more low-cost satellites to be launched.
josefresco 13y ago
Having taken an interest in this topic, and having watched the Sentate hearing (among others) where the ULA was asked to defend/validate it's model I find there's "sour grapes" everywhere among the incumbent players. You could easily swap the quoted line with this (related to Tesla) and it would still make sense: "We tried to make an electric car before," ... "Look how long and how much money it took for us to do that, and we still weren't successful for all parts."
BrandonMarc 12y ago
"impossible" ... This reminds me of a story Robert Cringely tells of Bill Gates. It seems mister Gates knew a certain thing was impossible to do, so he didn't try ... and lost million$ and market share when his competitor went and did it anyway. Here's the story: This business of taking software written for the 8086 processor and porting it to the 80286 normally required completely rewriting the software by hand, often taking years of painstaking effort. It wasn’t just a matter of recompiling the software, of having a machine do the translation, because Microsoft staunchly maintained that there was no way to recompile 8086 code to run on an 80286. Bill Gates swore that such a recompile was impossible. But Drew Major of Superset didn’t know what Bill Gates knew, and so he figured out a way to recompile 8086 code to run on an 80286. What should have taken months or years of labor was finished in a week, and Novell had won the networking war. Six years and more than $100 million later, Microsoft finally admitted defeat. http://www.cringely.com/2013/03/24/accidental-empires-chapter-14-counter-reformation/ http://www.cringely.com/2013/03/24/accidental-empires-chapte... Accidental Empires is a good book.

gatehouse 13y ago

I'm not sure that landing is more dangerous than takeoff. It's true that the thing is pointed towards the earth, but on the other hand there is a lot less fuel to explode.

ericcumbee 13y ago
The problem is that on launch the rocket is moving away from inhabited areas and out toward uninhabited areas during launch. On Landing it's going towards more densely populated areas. I wonder if maybe the solution is to land them on some uninhabited island, like the one the USAF targets ICBMs with dummy warheads on it from time to time.
- Crito 13y ago
  From what I have heard, the first stage will come in aimed away at the landing, or anything else, and then perform the divert maneuver that they've been testing with Grasshopper/F9R-Dev to put itself over the landing site at the last moment. That way if anything goes wrong before the last few seconds, the rocket won't fall where it was suppose to land. They are definitely planning on doing boost-back to the general area of the launch site though, not aiming for a target down-range. The launch this weekend will have them bringing the stage back closer to land than the previous attempt.
- deleted 13y ago
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lfuller 13y ago

"We'd pick them out of the ocean, but we spent a lot of time cleaning those things up when we got them back" And there's the rub. SpaceX is working on having reusable components land on solid ground.

icegreentea 13y ago
That quote is respect to the Shuttle Solid Rocket Booster - a part completely incomparable to the Falcon. It's really a throw away line about establishing an absolutely silly baseline. The meat of the 'argument' (and really, I don't believe it's an argument) is that the Shuttle Main Engines (the ones mounted on the tail of the Shuttle, the ones that land like a plane) had similar expectations of reusability, and ended up being absolutely terrible at reusablility. That's the point to address, not the throw away line.
- msandford 13y ago
  Right but they were awful because they were built and tested and qualified top-down, not bottom up. Feynman wrote about this idiocy at length: http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Appendix-F.txt http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/roger...
  - api 13y ago
    I also wonder about the use of hydrogen and how this impacted reusability. From what I've read hydrogen causes things like metal embrittlement, which is why SpaceX is completely avoiding it despite the higher specific impulse it yields.
    - InclinedPlane 13y ago
      LH2 is also super cryogenic. LOX and even liquid methane have boiling points higher than LN2. You can build launchers with them without even bothering to insulate the tanks, because the boiloff is so marginal over the duration of the launch. Whereas LH2 absolutely requires a lot of insulation, because it needs to be much, much colder. Worse yet, because of the super low density of LH2 you can't afford even a small amount of boiloff because that hurts your mass fraction immensely, and if you have a LOX/LH2 vehicle you've probably scraped and scrabbled for what meager mass fraction you've managed to achieve (through advanced alloys and so forth). One particular consequence of the use of LH2 with the Shuttle was that it resulted in an ice covered and foam insulated enormous external tank cheek-by-jowl with the delicate TPS coated underbelly of the orbiter during launch, as the vehicle rammed through the air at transonic then supersonic then hypersonic speeds. Another consequence of the LH2 choice for the Shuttle is that it didn't have enough thrust at sea level to get off the pad, so it needed high-thrust, low-cost boosters as a 0th stage. Solid rockets being the obvious go-to solution, those got used. In a very real way the choice to use LH2 resulted not just in much of the cost and complexity of the Shuttle system but also the death of 2 crews and the loss of 2 orbiters.

InclinedPlane 13y ago

They know nothing about reusability. Not even NASA has operated a truly reusable vehicle, the "reusability" of Shuttle was a joke (it still cost >$1 billion per flight) and they made every mistake possible when designing the vehicle. In contrast, Falcon 9 is an enormously simple launcher and reusability should be not only fairly straightforward but also advantageous. Moreover, because reusability of the F9 will actually save money (as opposed to the Shuttle where it required a massive ongoing operational cost) it will allow more money for ongoing development of improved vehicles (which SpaceX is already working on). Additionally, SpaceX isn't dumb, they've already tested running their engines through multiple cycles on test stands, they know the issues they'll run into and they have a reasonable idea how long they can expect to use them (spoilers: lots). And SpaceX has been operating reusable rockets over the course of several flights in the form of the the Grasshopper and F-9R-Dev vehicles which they've used for test flights.

tachyonbeam 13y ago
Honestly, their criticism sounds like the kind of thing any jealous nay sayer would say. They're trying to make it sound like an honest warning, but in reality, they're just afraid of having their crown stolen. They're basically telling SpaceX that their new approach has unforeseen risks. It's never been done before, hence it's risky, and it could well fail, it shouldn't even be tried. They're saying the NASA people had a working model for decades, and hence people should trust NASA's expertise more, not the new guy taking big risks trying new things. In reality, they can see that SpaceX knows what they're doing, and NASA has been falling behind for a long time, but that's really hard for NASA to accept. Still makes me sad to see this kind of attitude. Risk taking is necessary for innovation, and calculated risks often pay out big time, but the establishment is still always too afraid to take the said risks... And then when somebody else is there to take those risks, they try to discourage them.
- InclinedPlane 13y ago
  More or less. Here's the thing, SpaceX is almost certainly going to demonstrate partial launch vehicle reusability within the next year. And they're going to make it look easy. What's more, for the most part it will be easy. The damning bit is that what SpaceX ends up doing will be the sort of thing that could have been done back in the '80s or maybe even the '70s. But nobody had the right combination of pragmatism and vision to make it happen. But they could have, and there were bread crumbs all along the way. So why didn't they? A lot of it ultimately comes down to a few factors. Group think and bureaucracy. And fads. Yup, fads. One problem that orbital aerospace has been constantly afflicted with is the coolness factor problem. When pushing new projects it can be difficult to do so unless there is some sort of coolness factor, some way in which the new project is demonstrably more advanced than previous generation efforts. This is anathema to actual progress because most progress comes from copying, perfecting, and incremental innovation. The coolness factor is how we ended up with Shuttle (so cool), and X-33/VentureStar (much, much cooler). But look at the Falcon 9, it's just a 2 stage LOX/Kerosene booster, they've been building those since the '50s/'60s, it's the definition of uncool. But what it lacks in coolness it more than makes up for in usefulness. In terms of fads you can look to the Hydrogen rocket fad that still has a grip on a lot of engineers. LOX/LH2 undoubtedly has a very high Isp, and Isp is supremely important in the rocket equation. But it's not everything, and LH2 has a crapload of very serious downsides when it comes to using it in rocketry, many of which add significant cost to the system. The Hydrogen fad is why the Shuttle had SRBs (because the SSMEs couldn't generate enough thrust on their own to get off the pad) and thus is partially responsible for the Challenger disaster. It's also responsible for the Delta IV, which is an extremely expensive launcher. But back to breadcrumbs. They were there. In the early '90s the DC-X program demonstrated vertical takeoff/vertical landing was a feasible technology, and it did so using LOX/LH2 even. But the program was largely ignored because NASA was too dumb to see the promise of a reusable stage, since it wasn't cool enough relative to the idea of an SSTO RLV (in the same year as the last flight of the DC-X NASA got the X-33 program rolling). If NASA was just a little bit smarter and more practical it would have been easy to see the promise of the DC-X, easy to see the practicality of partial reusability, and easy to see the advantages of simpler launchers. But they didn't. Instead they pursued cool idea after cool idea, dumping around a billion dollars into X-33 alone. And when their overly ambitious cool ideas didn't pan out they ended up with nothing. And it was only through the comparative pragmatism of the defense department and the EELV program (which developed a couple boring 2-stage launchers) that the US had any reasonable launch capability whatsoever after the Shuttle program ended. Now it will be through the comparatively superior pragmatism (not to diminish the genius of SpaceX) that we'll end up with even greater launch capability and unprecedented reusability.

SeanLuke 13y ago

> Christophe Bonnal of the launcher directorate at French space agency CNES, agrees. “If you reuse, you stop producing, depending on the level of reusability,” he says. “So you end up with a permanent prototype, and to keep costs down you need to have a high rate of production.” I am not a rocket scientist. So someone please explain to me why this quote isn't the single stupidest thing I've read all day.

debt 13y ago
Haha, I know I should just upvote but this really made me chuckle pretty hard.
anmol 13y ago
With any advanced technology product, production volume plays a big role in making the underlying tech commodity and gradually dropping price per unit. F22's would be a lot cheaper to make (than today) if everyone had one in their backyard, like a Honda Civic.
- ithought 13y ago
  The cost of the F22 would go down if we just crashed every one on its first flight.
viraptor 13y ago
I think what he means (using a software library analogy): if you have a reusable component that is not worked on but satisfies your needs now, you're going to work around all problems and implement hacks to keep using the reusable component, instead of improving it - improving/maintaining that component could cost you another development team. You get technical debt / bitrot instead. If they keep component X too long, they'll need to reimplement / rebuild X from scratch in a few years when the original factory/production line doesn't exist anymore. This would require a lot of up-front cost that may be higher than just producing a new element of that type for every launch. I don't think the message was completely negative though: "depending on the level of reusability" sounds more like "this is hard, but if you pull it off with cost of restarting production << cost of reusability over N years, that's an achievement" Edit: many words

fredgrott 13y ago

shoud we remind NASA and CENS that in the 1980s USSR had a shuttle launched by remote control and land under the same computer control..

api 13y ago

Tangential thought: It really seems to me that only companies with the "California tech startup mentality" (whether they're in Cali or not) can actually do anything today. I'm starting to refer to the rest of the economy as the "legacy economy," "legacy industry," etc. I understand some of the reasons: bottom-up engineer-led engineering teams, lean operations, little or no bureaucracy compared to large older institutions, etc. But there seems to be something else too, some kind of difficult to quantify attitude or mentality. I get it, but I find it hard to describe except to say it's about believing in the future, believing that things are actually possible. Everyone else everywhere else seems to be looking backward and thinking of all the reasons things can't be done. Like this, for example. "Here, we're NASA, and here's why it can't be done." The NASA of the 50s and the 60s is rolling in its grave! Legacy economy indeed. Disrupt everything. Ditch it all and start over.

InclinedPlane 13y ago
Indeed. There are folks who see disruption as valuable and those who see it is as risky, dangerous. As to the NASA of the 1960s, that was a NASA who developed 4 different manned spacecraft in a 10 year period (Mercury, Gemini, Apollo CM & Apollo LM) and flew them on 4 different rockets (Atlas, Titan, Saturn I, Saturn V). That's the sort of activity that looks similar to what SpaceX is doing today and very dissimilar to what NASA is doing today (sinking billions per year into masses of bureaucratic BS and very little hardware).
- hga 13y ago
  Five different rockets! The first suborbital Mercury flights used Redstones, V-2 descendants that used alcohol and LOX. Followed by the Atlas that used kerosene and LOX like Space X, the Titan which used fuels that could be stored in the rocket for long terms, making it a practical ICBM (taken out of service in the mid-80s). All those were adopted from military missiles, and were followed by the purpose built Saturn I and V, and both of their first stages also used kerosene and LOX. Am I seeing a pattern here ^_^? (Quibbles: the "kerosene" used in rockets is actually highly refined stuff: https://en.wikipedia.org/wiki/RP-1 https://en.wikipedia.org/wiki/RP-1 and the Saturn upper stages used liquid hydrogen and LOX.)

voidlogic 13y ago

There have been very few reusable delivery systems (1? sorta?). That is too low of a sample size to draw conclusions. SpaceX has shown itself to be much more efficient than NASA and NASA's usual vendors, who is to say this will not build a better reusable delivery system? After all the last one was designed 40+ years ago by a very bureaucratic/political organization. Not to mention that Space uses Kerosene rather than Hydrogen for materials related reasons. Also, while some comparisons to the shuttle's main engine are warranted, refurb costs of the shuttle's solid boosters will not be comparable as they landed in the ocean rather than on dry land. Ocean water is nasty stuff for hitech equipment.