Florida Today reports on a NASA press conference about SpaceX’s Merlin engine problem. NASA says the engine is good to go for the next ISS mission, with certain precautions, but engineers still have not located a specific cause for the failure.

“Investigators think that extra testing may have contributed to a pressure chamber breach,” [NASA ISS program manager] Mike Suffredini said….

Suffredini said engineers had reviewed a huge amount of data but not produced a specific smoking gun,” which he said is not uncommon when investigating systems cannot be recovered.

The next engines in line to fly have been inspected thoroughly, and none has been tested beyond the levels needed to certify them for flight.

Emphasis added.

It sure is nice to bring your engines back home with you, rather than dumping them into the ocean, isn’t it?

That’s hardly news to anyone in the aviation industry. A&P mechanics hate it when a pilot who doesn’t bring part of the airplane back with him.

Still, common wisdom in the space business says expendable vehicles must be cheaper and easier to develop. After all, Von Braun did it that way!

We’re just saying.

Written by Astro1 on January 19th, 2013 , Commercial Space (General), SpaceX

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COMMENTS
    Tim commented

    Right now, the space industry has the worst of both worlds. Rockets are expensive and expendable. We would be better of with either reusable or disposable rockets. The difference between disposable and expendable is that the disposable rocket is designed to be easily manufactured and cheap to launch. It doesn’t matter if it’s thrown away if the rocket is so cheap to make that it can compete with reusables in cost. It’s hard to believe that is possible but when you consider that cost is secondary to performance, you began to see what went wrong in the launch vehicle industry.

    Reply
    January 19, 2013 at 8:03 pm
      admin commented

      Performance is important because customers want some assurance their expensive payload will reach orbit. NASA makes a big deal about astronauts but many payloads are worth more than the life of an astronaut. (Just ask an insurance company.)

      The idea that you can save money by reducing reliability is a common mistake. Southwest Airlines doesn’t skimp on maintenance to reduce costs. Unreliability actually costs money, rather than saving it.

      Reply
      January 19, 2013 at 9:32 pm
        Tim commented

        Depend on your payload. Consumables like food, water, air, and fuel are often cheaper than the launch vehicle that carries them into orbit. It’s worth reducing the price even if there’s an increase in the number of failed launches.

        Reply
        January 19, 2013 at 10:24 pm
          admin commented

          You said it yourself. “Consumables are often cheaper than the launch vehicle that carries them.” If you increase the number of failed launches, you increase the number of launch vehicles you have to buy. Not to mention tying up a launch pad and range for nothing more than a fireworks display. Maybe even a pad explosion, which puts the launch pad out of commission for a period of time. All of which costs money.

          Reply
          January 19, 2013 at 10:39 pm
            Tim commented

            The majority of launch failures is in propulsion or stage separation. Launch failures on the pad is rare. Secondly, launch vehicles can be launched from the ocean.

            January 19, 2013 at 11:04 pm
            admin commented

            Sea Launch has had a launch-pad failure. So, given that they launch at sea and have reliability problems, why aren’t they dirt cheap?

            January 20, 2013 at 12:10 am
            Tim commented

            I didn’t say launch from an ocean platform. Launch from the ocean itself.

            January 20, 2013 at 12:13 am
            admin commented

            That’s been tried before. The Naval Research Laboratory funded a project called SEALAR, run by Robert Truax, but never made as much progress as Truax expected. Not surprising. Anyone who’s served in the Navy will tell you everything’s 10 times harder at sea. Later, the Russian Navy launched a few satellites with converted SLBMs. Shitl’, Volna.

            January 20, 2013 at 12:59 am
            Tim commented

            Funding issues aren’t always made based on the merits of an idea. Any added difficulties from launching from the sea is offset by the the advantages. If it was that much harder to do anything on the ocean, we wouldn’t have ocean-going vessels or offshore drilling.

            January 20, 2013 at 6:59 am
            admin commented

            Ask the men and women who serve on those ships and rigs how easy it is. Nobody in the oil industry would tell you that drilling at sea is easier or cheaper than drilling on land. Even Hollywood knows how hard it is. They go to great lengths to avoid filming at sea, even building giant water tanks out in the Mojave Desert.

            January 20, 2013 at 1:28 pm
            Tim commented

            An ocean launched consist of unloading the rocket, which has already been prepped, from a vessel with a counterweight to keep the rocket vertical for launch. This is far simpler than working on an ocean platform.

            January 20, 2013 at 2:53 pm
            admin commented

            That’s what NRL was attempting to do with SEALAR. The idea originated with an Aerojet General study in the early 1960’s, for a rocket called Sea Dragon. By coincidence, we just published an article on it. The economics, however, as not as favorable as enthusiasts would have you believe.

            January 20, 2013 at 5:08 pm
            Tim commented

            The same could be said about reusuability. Recall the promise that shuttle would reduce the cost of space travel by an order of magnitude. This isn’t to say practical reusable launch vehicles are impossible, but that launching low-cost, mass-produced rockets from the ocean shouldn’t be dismissed over a rough start.

            January 23, 2013 at 10:46 pm
            admin commented

            The Shuttle was never reusable. It was rebuildable, at best.

            January 23, 2013 at 11:33 pm
            Tim commented

            IOW: a failed attempt at a reusuable launch vehicle.

            January 23, 2013 at 11:34 pm
            admin commented

            No, it was not an attempt to build a reusable launch vehicle. You don’t attempt to build a reusable launch vehicle by designing a giant expendable tank, for example.

            Calling a tail a leg does not make it a leg.

            January 28, 2013 at 12:58 am
            Tim commented

            So, according to you, airplanes that use drop tanks are not reusable.

            January 28, 2013 at 8:26 am
            admin commented

            “Drop tank” is a misnomer. It’s not what you think it is. Drop tanks are not discarded on normal missions. They are never discarded in peacetime because of the expense and the danger of dropping empty empty tanks over someone’s property. The drop jettison on my aircraft was disabled so the tank could not be jettisoned accidentally.

            Drop tanks don’t cost $100 million, either. Nor do they require weeks in the hangar to install. Numbers matter.

            January 28, 2013 at 1:12 pm
            Tim commented

            About half the RLV proposals are only partially-reusable. Most of them use an expendable upper stage and only reuse the first stage due to the difficulty of retrieving a stage from orbit. Even Space-X was considering that as an option for their Falcon 9 launch vehicle.

            January 28, 2013 at 1:35 pm
            admin commented

            Space-X is not the Alpha and Omega.

            Reusable means reusable, even if you say it means expendable. Is there a point to this word game?

            January 28, 2013 at 5:15 pm
            Tim commented

            There’s a reason why private companies looked into reusing only the first stage-reusability is difficult and can be more expensive than expendable if the flight rate is too low or the cost to service the RLV is too high. Take things on a case-by-case basis and not say “reusable-good, disposable-bad”

            January 28, 2013 at 9:00 pm
            admin commented

            Actually, there’s no reason for it, because it isn’t true. Again, SpaceX is not the private company out there (and even then, I’m not sure you’re interpreting Elon correctly.)

            January 28, 2013 at 11:33 pm
            Tim commented

            It is true. A low flight rates means the development cost and other fixed costs are distributed over fewer flights, which makes the per flight cost more expensive. Also, the shuttle was so maintenance-heavy that even with reusuable components, the shuttle cost more than an expendable. Again, take a launch system on a case-by-case basis and not assume a reusable will always be cheaper.

            January 29, 2013 at 10:22 am
            admin commented

            You’re stuck on strawman.

            Yes, if you (mis)take the Shuttle as a reusable vehicle, you can draw the conclusion you desire. So what?

            The Shuttle was not a reusable vehicle. Go out to your local airport and see how reusable vehicles operate. Are they designed for low flight rates? Heavy maintenance? Do they drop millions of dollars of hardware into the ocean?

            The fact that the Shuttle had some reusable components does not make it a reusable vehicle. A reusable vehicle needs to be designed for reuse. It requires reliability, maintainability, operability, intact abort modes — all of which the Shuttle lacked.

            You say you want to look at reusable and expendable vehicles on a case-by-case basis, but you only consider the strawman case of the Shuttle and a “low cost mass produced” paper rocket which no one has actually built.

            If you want case-by-case comparisons, compare any true reusable vehicle (not a rebuildable system like the Shuttle or Buran) against an expendable missile of comparable performance, in any flight regime. There are thousands of examples. Anything from a Piper Cub to the X-15.

            January 29, 2013 at 1:27 pm
            Tim commented

            These are not strawmen. An orbital launch vehicle can not be compared with an airplane. They have completely different mission profiles and parameters. An airplane doesn’t have over 95% of its weight in fuel. A launch vehicle does. An airplane doesn’t have to be launched in stages to fly fast enough to stay in orbit. A launch vehicle does. An airplane doesn’t have to made to be extremely light-weight and still survive a hypersonic re-enty. An RLV does. An expendable launch vehicle has more in common with any RLV on the drawing board than an airplane barring the launch vehicles that are launched from an airplane (and even then the only difference is that the launch vehicle is launched from the air and not the ground).

            January 30, 2013 at 12:02 am
            admin commented

            Yet another strawman. Nobody asked you to “compare an orbital launch vehicle with an airplane.”

            Once again: Compare any aircraft, or suborbital spacecraft to an expendable missile with similar performance. Or even a boat to a torpedo.

            In any regime you pick, you will find that reusable vehicles are cheaper, safer, more reliable than expendable ammunition with similar performance. Reusable vehicles — aircraft, spacecraft, boats — are transportation systems. Expendables — missiles, torpedoes — are ammunition.

            Transportation systems are designed for economy, safety, and reliability. Ammunition is not. When engineers set out to design a transportation system, it never occurs to them to sacrifice reusability, reliability, maintainability, and operability in the belief that will somehow be cheaper. The only time field where the ammunition mentality was adopted was space, and there it keeps failing. Do you think that’s just bad luck?

            You think that because a spacecraft has a rocket engine like a missile, it should be designed like a missile?

            Hm. A modern airliner has a jet engine like the V-1 missile, and it flies much higher and faster than airliners like the DC-3. Do you believe jetliners have more in common with Buzz Bombs than airplanes, then? Do you think they should be designed to crash at the end of each flight, like a giant Buzz Bomb? As you say, we can’t rule that that might be more economical! (Unless, of course, we employ a little simple math.)

            January 30, 2013 at 2:35 am
            admin commented

            You still need some sort of ship or platform to transport the rocket out to sea.

            January 20, 2013 at 5:12 pm
            admin commented

            You still need some sort of ship or platform to transport the rocket out to sea.

            January 20, 2013 at 5:12 pm
          admin commented

          In addition, while food, water, air might be cheap on Earth, they are considerably more valuable to the customers on ISS, who expect those things to show up. If you lose a rocket, you can’t just easily roll out a replacement, either. ISS has certain limits on vehicle operations. (Perhaps stricter than they need to be, but that’s another story.) Launch scheduling becomes quite complicated.

          Reply
          January 19, 2013 at 10:44 pm