Antares rocket explosion: The question of using decades-old Soviet engines(washingtonpost.com)
washingtonpost.com
Antares rocket explosion: The question of using decades-old Soviet engines
http://www.washingtonpost.com/news/morning-mix/wp/2014/10/29/antares-rocket-explosion-the-question-of-using-decades-old-soviet-engines/
13 comments
Isn't this much more a question of reliability and track record than 10% performance differences?
Both reliability and performance. And also reliability is something which you estimate, calculate basing on some models - it's probability, not a guarantee. How would you estimate the reliability of an engine which run over 3 hours on a test stand? Of course you might prefer a well known fuels, industry-proven range of pressures and other engineering solutions, and you test them on Earth first - but after that you have to fly.
Track records are tricky for rocket systems. Since the first Sputnik, over the 57 years the humanity had may be - roughly - 4000 launches of space rockets of all kinds, with many different fuels, engines, sizes etc. It's relatively rare when you have a good track record which is measured by many tens of flights - let alone hundreds. When a system flew 20 times it's already considered rather mature - double so if those were all successful flights. So it's quite usual to use a new engine in a new design of rocket - in fact it's rare when you have many different rockets with the same engine type or many different engines used on the same rocket. Rockets and engines are usually optimized to each other - particularly rockets are built around engines, since margins are quite thin.
Track records are tricky for rocket systems. Since the first Sputnik, over the 57 years the humanity had may be - roughly - 4000 launches of space rockets of all kinds, with many different fuels, engines, sizes etc. It's relatively rare when you have a good track record which is measured by many tens of flights - let alone hundreds. When a system flew 20 times it's already considered rather mature - double so if those were all successful flights. So it's quite usual to use a new engine in a new design of rocket - in fact it's rare when you have many different rockets with the same engine type or many different engines used on the same rocket. Rockets and engines are usually optimized to each other - particularly rockets are built around engines, since margins are quite thin.
Most definitely that's a question that needs to be asked, but before you ask that, you need to ask what engines have performance specs worthy of further consideration. If you did it in reverse order, you're liable to get finalists like whatever they put in those volvos with a couple hundred thousand miles on them. :P
It doesn't matter how reliable the engine is if it's not performant enough for the envisioned task.
As to your question about reliability and track record, it's kinda hard to base the decision on past launch performance since most rockets-engines are built to a specific rocket and vice versa. These things aren't like a used car where you can look at thousands of unique datapoints.
And it generally cost prohibitive to do a full dry-run with only a cargo full of, say, bricks, because a single launch costs well north of a hundred million dollars. Instead you have to run a lot of ground based tests and figure a bunch of probabilities.
These guys won a one point something billion dollar contract from NASA to deliver shit to the ISS. NASA's not exactly well funded and not exactly known for flying by the seat of their pants, even by government agency standards. In order to win that contract they needed to prove to NASA's satisfaction that there was a high probability that their rocket would get to ISS without a major problem, let alone one as catastrophic and uncorrectable as exploding a few hundred feet above the pad.
It doesn't matter how reliable the engine is if it's not performant enough for the envisioned task.
As to your question about reliability and track record, it's kinda hard to base the decision on past launch performance since most rockets-engines are built to a specific rocket and vice versa. These things aren't like a used car where you can look at thousands of unique datapoints.
And it generally cost prohibitive to do a full dry-run with only a cargo full of, say, bricks, because a single launch costs well north of a hundred million dollars. Instead you have to run a lot of ground based tests and figure a bunch of probabilities.
These guys won a one point something billion dollar contract from NASA to deliver shit to the ISS. NASA's not exactly well funded and not exactly known for flying by the seat of their pants, even by government agency standards. In order to win that contract they needed to prove to NASA's satisfaction that there was a high probability that their rocket would get to ISS without a major problem, let alone one as catastrophic and uncorrectable as exploding a few hundred feet above the pad.
Most definitely that's a question that needs to be asked, but before you ask that, you need to ask what engines have performance specs worthy of further consideration. If you did it in reverse order, you're liable to get finalists like whatever they put in those volvos with a couple hundred thousand miles on them. :P
It doesn't matter how reliable the engine is if it's not performant enough for the envisioned task.
As to your question about reliability and track record, it's kinda hard to base the decision on past launch performance since most rockets-engines are built to a specific rocket and vice versa. These things aren't like a used car where you can look at thousands of unique datapoints, or use the same engine in the silverado that you use in the corvette (yeah, this is actually true. different ecu settings, though).
And it generally cost prohibitive to do a full dry-run with only a cargo full of, say, bricks, because a single launch costs well north of a hundred million dollars. Instead you have to run a lot of ground based tests and figure a bunch of probabilities.
These guys won a one point something billion dollar contract from NASA to deliver shit to the ISS. NASA's not exactly well funded and not exactly known for flying by the seat of their pants, even by government agency standards. In order to win that contract they needed to prove to NASA's satisfaction that there was a high probability that their rocket would get to ISS without a major problem, let alone one as catastrophic and uncorrectable as exploding a few hundred feet above the pad.
It doesn't matter how reliable the engine is if it's not performant enough for the envisioned task.
As to your question about reliability and track record, it's kinda hard to base the decision on past launch performance since most rockets-engines are built to a specific rocket and vice versa. These things aren't like a used car where you can look at thousands of unique datapoints, or use the same engine in the silverado that you use in the corvette (yeah, this is actually true. different ecu settings, though).
And it generally cost prohibitive to do a full dry-run with only a cargo full of, say, bricks, because a single launch costs well north of a hundred million dollars. Instead you have to run a lot of ground based tests and figure a bunch of probabilities.
These guys won a one point something billion dollar contract from NASA to deliver shit to the ISS. NASA's not exactly well funded and not exactly known for flying by the seat of their pants, even by government agency standards. In order to win that contract they needed to prove to NASA's satisfaction that there was a high probability that their rocket would get to ISS without a major problem, let alone one as catastrophic and uncorrectable as exploding a few hundred feet above the pad.
how does the Vulcain2 compare?
The NK-33 may be old, but it offers equal or superior performance to anything made in the US. Another engine, the RD-180 is used in the Atlas. US industries have the rights to manufacture, but want $800M and 4 years to build it or create a new engine. That tells you the state of US tech.
http://aviationweek.com/defense/aerojet-rocketdyne-targets-2...
Video on Russian/Ukranian engines: http://www.youtube.com/watch?v=TMbl_ofF3AM
http://aviationweek.com/defense/aerojet-rocketdyne-targets-2...
Video on Russian/Ukranian engines: http://www.youtube.com/watch?v=TMbl_ofF3AM
Not sure what proper HN etiquette on this is, but I made a comment on the launch news story on this exact subject:
https://news.ycombinator.com/item?id=8525057
TLDR- Those engines may be 50 years old, but they're a technological marvel. Using them is a little crazy, but I'm sure Orbital saw it as the "least crazy" of three options: building a new engine from scratch, buying prohibitively expensive engines from Rocketdyne, or buying risky but cheap engines from Russia.
https://news.ycombinator.com/item?id=8525057
TLDR- Those engines may be 50 years old, but they're a technological marvel. Using them is a little crazy, but I'm sure Orbital saw it as the "least crazy" of three options: building a new engine from scratch, buying prohibitively expensive engines from Rocketdyne, or buying risky but cheap engines from Russia.
The design is a technical marvel, but it won't keep the metal from corroding, and this isn't the first sign of trouble -- a few months ago, a different AJ-26 blew up on a test stand. It isn't yet clear that the engine was at fault in the Antares fire (trouble in the tankage or fuel lines could have cascaded down, among other fun possibilities) -- but if the engine does turn out to be at fault, the remaining stock will certainly get more attention.
What makes Rocketdyne engines less risky? Maybe they are both expensive and risky.
Well the CEO of a rocket company should have a better response than "I wish there were better engines to use." Maybe with that multi billion dollar contract you can, oh I don't know, build one?
SpaceX certainly built their own and they seem to be working quite well thusfar.
To be fair SpaceX's last launch (Aug 22) exploded too. It was a test, not a real mission, but to quote Elon: "Rockets are tricky."
For starters, that wasn't an actual launch to orbit, that's just the low altitude testing frames for landing/reusability.
It was deliberately destroyed as a safety measure because the rocket was moving out of the testing zone and the onboard system wasn't able to compensate fast enough.
Apparently Elon and a few others were a little annoyed that more (appropriate) risk wasn't being taken in those test flights, because they'd been 100% successful.
Secondly, their launches of the production Falcon 9's have been 100% successful (with one launch not achieving a secondary objective). Additionally, after the first three Falcon 1's, they were also 100% successful.
And finally, they launched two Falcon 9's since August 22nd: September 7th: Asiasat 6 launch (Geosync), and September 21st - Dragon CRS-4 (ISS).
It was deliberately destroyed as a safety measure because the rocket was moving out of the testing zone and the onboard system wasn't able to compensate fast enough.
Apparently Elon and a few others were a little annoyed that more (appropriate) risk wasn't being taken in those test flights, because they'd been 100% successful.
Secondly, their launches of the production Falcon 9's have been 100% successful (with one launch not achieving a secondary objective). Additionally, after the first three Falcon 1's, they were also 100% successful.
And finally, they launched two Falcon 9's since August 22nd: September 7th: Asiasat 6 launch (Geosync), and September 21st - Dragon CRS-4 (ISS).
Agree. And those Merlin-1D seem to be very efficient from economical point of view. Technically they are also good - record setting for open cycle engines.
However, NK-33 are closed cycle and have better Isp. Economically they also made a lot of sense for Orbital, since they were bought as already made for another project. It can be justified.
However, NK-33 are closed cycle and have better Isp. Economically they also made a lot of sense for Orbital, since they were bought as already made for another project. It can be justified.
Sure but I don't consider a test launch the same as "production" launch carrying payloads for ISS or other companies to hurl into orbit. Slightly different in that it is more acceptable for a test rocket trying out new functionality with no payload might fail.
Nu? SpaceX has had two successful launches since Aug. 22 -- AsiaSat 6 on September 7, and the CRS-4 ISS supply mission on September 21. The test article that blew up on the 22nd was not launch capable, and was reportedly missing some safety systems that are present on production vehicles.
Yup. IIRC it was auto triggered by some onboard system because of one of those 'anomalies'.
Minor nitpick: Frank Culbertson is an executive vice president at Orbital, not the CEO.
The CEO mentioned in the article (Elon Musk) said "there is better technology to use".
The CEO mentioned in the article (Elon Musk) said "there is better technology to use".
Building a new engine is, quite literally, rocket science. On the plus side, we know the problems can be solved, because we've done it before. On the minus side, a lot of that knowledge has been lost and needs to be recreated or redesigned. We can't easily rebuild the Saturn V, for example, even though its design would work well for many of today's launches. [1] New rockets are being designed, but its a major undertaking. [2] NASA's SLS is in the $18 billion range. [3]
[1] http://amyshirateitel.com/2011/04/03/the-lost-art-of-the-sat...
[2] http://en.wikipedia.org/wiki/Saturn_V#Proposed_successors
[3] http://en.wikipedia.org/wiki/Space_Launch_System#Program_cos...
[1] http://amyshirateitel.com/2011/04/03/the-lost-art-of-the-sat...
[2] http://en.wikipedia.org/wiki/Saturn_V#Proposed_successors
[3] http://en.wikipedia.org/wiki/Space_Launch_System#Program_cos...
That's a pretty hard problem. F-1 took unimaginable efforts to make right - event though the only unusual, untested parameter for this engine is its size. RD-170 took all the genius of Glushko - including his previous somewhat successful experience with RD-270, which deserves a whole story for itself - to get working properly. With all hindsight, only the forth Merlin of SpaceX is actually pushing technical limits - and that's in XXI century. Then, there is the issue of time - to build an engine from scratch is easy to delay a rocket for a year - if you're lucky and do that right from the first attempt.
So Orbital words can be taken seriously and for the face value. NK-33 is a pretty good engine.
So Orbital words can be taken seriously and for the face value. NK-33 is a pretty good engine.
The B-52 is just as old, and is expected to have served for almost a century once retired. It's not the same as rockets, but "oh it's old" isn't as compelling of an argument as failure rate, which - how many have there been using these engines?
Is that data available?
Is that data available?
"We saw rust and crack, so we repaired them" seems like the culprit. Not the age.
I was commenting more on the (not surprising) comments from their detractors, not so much on the official explanation.
There's a lot less redundancy in a rocket. A B-52 can keep flying if a bunch of stuff stops working or falls off. You just cannot design a rocket that way.
Those B-52's have been maintained (with some parts from boneyard-ed planes, though) and presumably at least occasionally flown all that time...
My admittedly uninformed opinion is that it just doesn't make any sense. I don't care how good the Russians are/were at making rockets. First of all, surely there has been significant progress in all aspects of the design and manufacturing of such an item. And second, who knows how well the engines have been stored, cared for, maintained and transported over the past 40 years. I would think you'd want to have more visibility into such a thing for this type of component.
Elon: It “has a contract to resupply the International Space Station, and their rocket honestly sounds like the punch line to a joke,” he said. “It uses Russian rocket engines that were made in the ’60s. I don’t mean their design is from the ’60s — I mean they start with engines that were literally made in the ’60s and, like, packed away in Siberia somewhere.”
Orbital: "we did discover there were some effects of aging since they had been in storage for awhile, including some stress corrosion cracking,”
I could see Elon offering to supply Orbital with some US-made engines. But maybe that wouldn't satisfy NASA's desire for diversity.
Elon: It “has a contract to resupply the International Space Station, and their rocket honestly sounds like the punch line to a joke,” he said. “It uses Russian rocket engines that were made in the ’60s. I don’t mean their design is from the ’60s — I mean they start with engines that were literally made in the ’60s and, like, packed away in Siberia somewhere.”
Orbital: "we did discover there were some effects of aging since they had been in storage for awhile, including some stress corrosion cracking,”
I could see Elon offering to supply Orbital with some US-made engines. But maybe that wouldn't satisfy NASA's desire for diversity.
There hasn't been much development in this types of engines since the moon race. And we may have even gone backwards, because a lot of the institutional knowledge and probably some of the documentation is lost.
And the punchline is, those engines weren't even very good when they were first made all those decades ago.
If they article is right, they were first developed for use on the N1 rocket, the Soviet moon-rocket counterpart to America's Saturn V. There's a reason why Saturn V beat the N1 to the moon -- the N1 had a distressingly consistent habit of blowing up:
N1-L3 was underfunded and undertested, and started development in October 1965, almost four years after the Saturn V. The project was badly derailed by the death of its chief designer Sergei Korolev in 1966. Each of the four attempts to launch an N1 failed; during the second launch attempt the N1 rocket crashed back onto its launch pad shortly after liftoff and exploded, resulting in one of the largest artificial non-nuclear explosions in human history. (Source: http://en.wikipedia.org/wiki/N1_(rocket))
If they article is right, they were first developed for use on the N1 rocket, the Soviet moon-rocket counterpart to America's Saturn V. There's a reason why Saturn V beat the N1 to the moon -- the N1 had a distressingly consistent habit of blowing up:
N1-L3 was underfunded and undertested, and started development in October 1965, almost four years after the Saturn V. The project was badly derailed by the death of its chief designer Sergei Korolev in 1966. Each of the four attempts to launch an N1 failed; during the second launch attempt the N1 rocket crashed back onto its launch pad shortly after liftoff and exploded, resulting in one of the largest artificial non-nuclear explosions in human history. (Source: http://en.wikipedia.org/wiki/N1_(rocket))
> There's a reason why Saturn V beat the N1 to the moon -- the N1 had a distressingly consistent habit of blowing up:
That, too, was a symptom, not a cause.
The history of the N1 program is complex. As a westerner, you're probably more inclined to quickly thumb your nose at it, but the program failed for a sum of non-technical reasons.
Korolev died early during the project. That alone was a major blow.
Then, the Communist Party severely cut the funds needed for the project. They couldn't even test the rockets properly. Their "tests" were the actual live launches. Imagine if NASA was operating like that.
They did the best they could, but with the chief engineer gone, and with almost no money, they couldn't get very far. I see the whole thing not as proof of lack of competence, but rather as a heroic effort against literally insurmountable difficulties.
Someone should make a movie out of it, starting with Korolev's awesome early work before WW2, going through him being exiled in labor camp in Siberia by Stalin, then his rehabilitation and then the Sputnik and Gagarin, the start of the N1, Korolev's death (hastened by poor health after his siberian sojourn), and ending with the N1 being stopped and the engines being hidden in a facility against the wishes of the Party higher-ups to have them destroyed. A Dostoevsky drama kind of vibe would be quite appropriate, I guess.
That, too, was a symptom, not a cause.
The history of the N1 program is complex. As a westerner, you're probably more inclined to quickly thumb your nose at it, but the program failed for a sum of non-technical reasons.
Korolev died early during the project. That alone was a major blow.
Then, the Communist Party severely cut the funds needed for the project. They couldn't even test the rockets properly. Their "tests" were the actual live launches. Imagine if NASA was operating like that.
They did the best they could, but with the chief engineer gone, and with almost no money, they couldn't get very far. I see the whole thing not as proof of lack of competence, but rather as a heroic effort against literally insurmountable difficulties.
Someone should make a movie out of it, starting with Korolev's awesome early work before WW2, going through him being exiled in labor camp in Siberia by Stalin, then his rehabilitation and then the Sputnik and Gagarin, the start of the N1, Korolev's death (hastened by poor health after his siberian sojourn), and ending with the N1 being stopped and the engines being hidden in a facility against the wishes of the Party higher-ups to have them destroyed. A Dostoevsky drama kind of vibe would be quite appropriate, I guess.
You're perhaps mistaking NK-33 for their predecessor, NK-15, which was used in all 4 unsuccessful N1 flights?
So the predecessor was involved in 4 consecutive mishaps and the successor never even used? Not sure who is mistaking here.
The reason NK-15 were exploding was traced back to turbopumps. Those were completely redesigned, from scratch, for NK-33. That alone justifies a new name for the engine. Then, unlike NK-15, NK-33 are multi-start engines. Were tested for ridiculously long work times - one worked non-stop for ~14000 (fourteen thousands) seconds on a stand.
To save anyone else who doesn't trust themselves doing simple time based math and googling 14000 seconds in hours:
~14000 seconds = ~3.9 hours
~14000 seconds = ~3.9 hours
Context for the Musk Quotes, his 2012 Wired interview:
http://www.wired.com/2012/10/ff-elon-musk-qa/all/
http://www.wired.com/2012/10/ff-elon-musk-qa/all/
Uninformed, yes :( .
There are theoretical limits for how high Isp - the specific impulse, defined as how much thrust, in, say, pounds of force, you can get from a unit of fuel flow, going into the engine, in, say, pounds of mass per second. The engines created in '60s are already rather close to that theoretical limit - so saying that you can do much better just because decades has passed is similar to saying "well, surely we had SR-71 flying back in '70s already - by today we ought to have all civil aviation routinely doing at least Mach 2".
So - no, it's pretty hard, including for fundamental reasons, to make engines much better that NK-33 by Isp. And that parameter is of paramount importance for a rocket engine.
Mind you, this is still not the only parameter. After all, you probably care a lot about economic efficiency. Elon Musk seems to understand that pretty well - and SpaceX engines, while lacking technically, could be in a much better position economically. Next, you're right that design and manufacturing aren't standing still. Both control of materials parameters and the ability to convert the raw material into an engineered device substantially rose - talking about, say, 3D printing engines or parts, which happens rather frequently now, but didn't in '70s.
So it's a complicated matter. However, NK-33 still have good technical parameters, and were bought inexpensively - in '90s, when Russia was severely starved for cash. Why not to use something which is already there, and not expensive? That's quite a rational decision Orbital - and Aerojet before them - took.
Regarding the second part, about storage. Surely this is unprecedented case. That's why the engines were tested - many times, both in Russia and in USA, and also analysed, trying to predict how several decades of storage could affect engines. The results were apparently positive - of course you and I don't have the original raw data which was used to make that decision. But don't think the engines just were, say, buried underground; their storage history is roughly known and isn't that different from other products of heavy machinery industry.
So I think Elon is habitually being overreacting in regard to Orbital usage of those engines. May be it has something to do with Elon's unsuccessful attempts to strike a deal with Russian space industry back when SpaceX was really young - or may be it's just a tradition for him, Elon sometimes says something out of proportions, even though SpaceX real - smaller - results are undeniable. Elon misses the point - it's only for uninformed the phrase "rocket engines made in USSR 40 years ago" would mean "unacceptable variant". George Sutton, author of "History of Liquid Propellant Rocket Engines" mentions that USSR spent far more towards rocket engine research than all other countries combined, and NK-33 is one of the serious achievements of Soviet rocket school. Don't discount something off hand just because it's old and foreign.
There are theoretical limits for how high Isp - the specific impulse, defined as how much thrust, in, say, pounds of force, you can get from a unit of fuel flow, going into the engine, in, say, pounds of mass per second. The engines created in '60s are already rather close to that theoretical limit - so saying that you can do much better just because decades has passed is similar to saying "well, surely we had SR-71 flying back in '70s already - by today we ought to have all civil aviation routinely doing at least Mach 2".
So - no, it's pretty hard, including for fundamental reasons, to make engines much better that NK-33 by Isp. And that parameter is of paramount importance for a rocket engine.
Mind you, this is still not the only parameter. After all, you probably care a lot about economic efficiency. Elon Musk seems to understand that pretty well - and SpaceX engines, while lacking technically, could be in a much better position economically. Next, you're right that design and manufacturing aren't standing still. Both control of materials parameters and the ability to convert the raw material into an engineered device substantially rose - talking about, say, 3D printing engines or parts, which happens rather frequently now, but didn't in '70s.
So it's a complicated matter. However, NK-33 still have good technical parameters, and were bought inexpensively - in '90s, when Russia was severely starved for cash. Why not to use something which is already there, and not expensive? That's quite a rational decision Orbital - and Aerojet before them - took.
Regarding the second part, about storage. Surely this is unprecedented case. That's why the engines were tested - many times, both in Russia and in USA, and also analysed, trying to predict how several decades of storage could affect engines. The results were apparently positive - of course you and I don't have the original raw data which was used to make that decision. But don't think the engines just were, say, buried underground; their storage history is roughly known and isn't that different from other products of heavy machinery industry.
So I think Elon is habitually being overreacting in regard to Orbital usage of those engines. May be it has something to do with Elon's unsuccessful attempts to strike a deal with Russian space industry back when SpaceX was really young - or may be it's just a tradition for him, Elon sometimes says something out of proportions, even though SpaceX real - smaller - results are undeniable. Elon misses the point - it's only for uninformed the phrase "rocket engines made in USSR 40 years ago" would mean "unacceptable variant". George Sutton, author of "History of Liquid Propellant Rocket Engines" mentions that USSR spent far more towards rocket engine research than all other countries combined, and NK-33 is one of the serious achievements of Soviet rocket school. Don't discount something off hand just because it's old and foreign.
> That's why the engines were tested - many times, both in Russia and in USA, and also analysed, trying to predict how several decades of storage could affect engines.
One of the refurbished NK-33's failed on a test stand in Louisiana, destroying the engine and causing heavy damage to the test stand during static testing in May:
http://www.nasaspaceflight.com/2014/05/antares-aj-26-engine-...
One of the refurbished NK-33's failed on a test stand in Louisiana, destroying the engine and causing heavy damage to the test stand during static testing in May:
http://www.nasaspaceflight.com/2014/05/antares-aj-26-engine-...
> Why not to use something which is already there, and not expensive?
If engines were the cause of the recent failure, they've just proven to be quite expensive for Orbital.
The company's in a pretty weird place right now. After destroying one on the bench and one in flight, the cost of insuring a flight with these engines has gone up quite a bit. None of the ways to get flying this class of rocket again - new engine production, recertifying and insuring flights using the old engine, etc. - can be done on the cheap.
The thing they might have going for them is the contract with NASA. I don't know the details of that.
If engines were the cause of the recent failure, they've just proven to be quite expensive for Orbital.
The company's in a pretty weird place right now. After destroying one on the bench and one in flight, the cost of insuring a flight with these engines has gone up quite a bit. None of the ways to get flying this class of rocket again - new engine production, recertifying and insuring flights using the old engine, etc. - can be done on the cheap.
The thing they might have going for them is the contract with NASA. I don't know the details of that.
Yes and no.
Rocket engine design has not actually made that much progress in the meanwhile. It's not the design that was the issue.
Also, the Russians were VERY good at making rocket engines.
The real problem is that these are engines actually made decades ago, and stored under a tarp in a former Soviet facility for a long time before they were purchased by Orbital as the cheap option.
Rocket engine design has not actually made that much progress in the meanwhile. It's not the design that was the issue.
Also, the Russians were VERY good at making rocket engines.
The real problem is that these are engines actually made decades ago, and stored under a tarp in a former Soviet facility for a long time before they were purchased by Orbital as the cheap option.
I've seen photos of the hangar where they were stored. Looks like some decent conditions. Regardless, they were inspected - with replacing proper parts, like in valves - and tested on stands. And x-ray checks are standard for this kind of systems.
I can highly recommend these two books for an
engaging introduction to getting things right in the rocket business:
Ignition! An informal history of liquid rocket propellants
http://www.goodreads.com/book/show/677285.Ignition_
and
Space Systems Failures: Disasters and Rescues of Satellites, Rocket and Space Probes
http://www.goodreads.com/book/show/1015478.Space_Systems_Fai...
Also note that we don't know yet if the NK-33/AJ-26 engine was the cause of failure. Sometimes the most visible possibility wasn't the original cause of the problem.
I don't think it's so much about age as it is about design. From my understanding the original NK 33 rocket engines used a unique oxygen-rich fuel turbo-pump mechanism that the west considered too dangerous. Aerojet-Rocketdyne took these engines and refurbished them and therein lies the question. But I think it might be premature to ask this given they haven't told us what happened.
The thing is they are very powerful engines and the price was right.
The thing is they are very powerful engines and the price was right.
It's not that unique - in Russian space school oxidizer-rich turbines are routine. Proton, for example, used to have - until latest years - a pretty solid track record, especially for first stage engines, and those engines use N2O4 for turbines. Considering that N2O4 is burned with some amount of (CH3)2N-NH2, making HNO3... the gas going to chamber from turbine is the nitric acid. Still engines work just fine.
One of big reasons for Russians to use oxydizer-reach gas generators is that on the rocket there usually much more oxidizer - by mass - than fuel, which makes the flow through the turbine much bigger - several times. So efficiency of turbopumps goes up. That justifies the complexity of having oxidizer-rich gas flow before the chamber.
One of big reasons for Russians to use oxydizer-reach gas generators is that on the rocket there usually much more oxidizer - by mass - than fuel, which makes the flow through the turbine much bigger - several times. So efficiency of turbopumps goes up. That justifies the complexity of having oxidizer-rich gas flow before the chamber.
For someone who doesn't know much about aerospace engineering, can someone outline the actual challenge with getting something like this right?
What's the missing piece that'll effectively eliminate accidents like this? Or is this one of those things that will just happen from time to time because going to space takes a lot of math that we don't fully understand yet?
I was just under the impression that this was a very well known area of science.
What's the missing piece that'll effectively eliminate accidents like this? Or is this one of those things that will just happen from time to time because going to space takes a lot of math that we don't fully understand yet?
I was just under the impression that this was a very well known area of science.
I think this is fundamentally pretty hard problem. It involves control of turbulence, and this is a big in general unsolved problem today. That includes hypersonic flights, thermonuclear plasma control... Rocket engines work on the edge of material capabilities, and fluctuations - which you want to tame to guarantee things like that won't happen - are hard to deal with.
With these particular engines, you also have the variable factor of them being stored for decades in a warehouse, and all the issues with metal corrosion, fatigue, degradation, etc. that come with that.
I'm not a materials engineer, but I could imagine things like seasonal temperature changes, humidity, rough handling, changes in the metallurgical properties of the alloys they used over time could all affect the ability of the engine components to withstand high temperatures and pressures.
I'm not a materials engineer, but I could imagine things like seasonal temperature changes, humidity, rough handling, changes in the metallurgical properties of the alloys they used over time could all affect the ability of the engine components to withstand high temperatures and pressures.
So these engines were built when Paul McCartney was 23 years old?
Apparently Orbital Sciences scoured the museums and antique shops in Russia and picked up enough of these engines to base a new rocket on them.
The reason they were surplus was that the rocket that they were built for was canceled, because the engines exploded on each of the four test launches conducted.
Orbital Sciences was once a scrappy startup. Books were written about it. However, this is just embarrassing.
Apparently Orbital Sciences scoured the museums and antique shops in Russia and picked up enough of these engines to base a new rocket on them.
The reason they were surplus was that the rocket that they were built for was canceled, because the engines exploded on each of the four test launches conducted.
Orbital Sciences was once a scrappy startup. Books were written about it. However, this is just embarrassing.
Aerojet bought those engines from Russia - the original manufacturer - in 1990-s. No need for Orbital to scour museums.
No, engines didn't explode. Were actually never flown before the first Antares lifted off. But performed pretty well on stands.
No, engines didn't explode. Were actually never flown before the first Antares lifted off. But performed pretty well on stands.
Are you were claiming that there were no failures of the NK-33 engine on any of the four N1 flights that exploded during first stage burn?
Yes.
NK-33 never flew on N-1. They were intended to fly on N-1 in its fifth flight - which never happened, because Glushko closed the program after becoming the head of the Energiya company.
NK-33 never flew on N-1. They were intended to fly on N-1 in its fifth flight - which never happened, because Glushko closed the program after becoming the head of the Energiya company.
When all else fails, blame Russia.
No one is blaming Russia.
We're blaming the age of rocket engines (that just happened to come from Russia).
We're blaming the age of rocket engines (that just happened to come from Russia).
And why not prominently state "Soviet" in the title.
Here's the thing: the rocket itself is not 'decades old'. The design is.
This is tantamount to saying "Oh, cars use a decades old design.. they must be terrible!"
The article also completely overlooks the fact that Russia launched a rocket with the supplies within 24 hours of the failure. http://news.yahoo.com/cause-sought-space-supply-rocket-08252...
This is tantamount to saying "Oh, cars use a decades old design.. they must be terrible!"
The article also completely overlooks the fact that Russia launched a rocket with the supplies within 24 hours of the failure. http://news.yahoo.com/cause-sought-space-supply-rocket-08252...
But cars are... they are extremely inefficient to more modern designs. We just haven't found something better then the internal combustion engine.
The article refers to them as "refurbished Soviet engines" which certainly sounds like Some parts of the engines are original.
Actually, the engines are. The AJ-26 is a rebuilt NK-33, originally built in the early 1970s.
The rocket engine is actually decades old. The engines were built many years ago, then stored under a tarp in a Russian facility somewhere. They were supposed to be dismantled, but some Party official risked his neck by sparing them the destruction, hiding them in some forgotten facility - however, the flip side to that was that the engines were stored in probably not the best conditions.
Orbital used them because they were the cheap option.
Orbital used them because they were the cheap option.
Not exactly. The engines themselves are decades old, Orbital Science is quoted as saying
"'As we went through testing, we did discover there were some effects of aging since they had been in storage for awhile, including some stress corrosion cracking,' Culbertson conceded at the time. 'That’s what we [corrected] with weld repairs and other inspections.'"
They got the engines that were decades old, and they've been fixing problems that they have found, and refurbishing them and installing them into rockets. It doesn't say they have built new engines on the old designs. That would have been better, because then you would have someone who had designed the engine on staff and could understand it in a deep way.
Presumably Orbital is designing their own engines now, or contracting with someone to do so, perhaps their go to market strategy was "Get some things into space with these old surplus engines, use the revenue/time to design/test/manufacture our own engines, and then continue on with our own bespoke design." I don't know of course if that was their intention or not.
"'As we went through testing, we did discover there were some effects of aging since they had been in storage for awhile, including some stress corrosion cracking,' Culbertson conceded at the time. 'That’s what we [corrected] with weld repairs and other inspections.'"
They got the engines that were decades old, and they've been fixing problems that they have found, and refurbishing them and installing them into rockets. It doesn't say they have built new engines on the old designs. That would have been better, because then you would have someone who had designed the engine on staff and could understand it in a deep way.
Presumably Orbital is designing their own engines now, or contracting with someone to do so, perhaps their go to market strategy was "Get some things into space with these old surplus engines, use the revenue/time to design/test/manufacture our own engines, and then continue on with our own bespoke design." I don't know of course if that was their intention or not.
Orbital now has ATK experience on board. Feels natural to switch to all-solid rockets - like other Orbital designs. However for now, the Antares is the biggest Orbital rocket, and it's designed with NK-33. Definitely need to investigate this event and make decisions.
It's better to use engines which were just created - or just manufactured - but sometimes there are reasons to prefer old engines to new ones. Age is not the only factor.
It's better to use engines which were just created - or just manufactured - but sometimes there are reasons to prefer old engines to new ones. Age is not the only factor.
No, the engine is literally decades old. From http://en.wikipedia.org/wiki/NK-33 :
"Nearly thirty years after they were built, disbelieving rocket engineers were led to the warehouse. One of the engines was later taken to America, and the precise specification of the engine was demonstrated on a test stand."
"Nearly thirty years after they were built, disbelieving rocket engineers were led to the warehouse. One of the engines was later taken to America, and the precise specification of the engine was demonstrated on a test stand."
No, in this case part of the rocket itself was decades old. Orbital used AJ-26 engines for the first stage, which are refurbished NK-33 engines originally built for the Soviet moon program. [1]
[1] http://en.wikipedia.org/wiki/NK-33
[1] http://en.wikipedia.org/wiki/NK-33
Downvote. The engines were indeed originally _built_ in the 60s or 70s and have literally been sitting around for the vast majority of the time since.
Second, not sure what your point is with the Russian launch. It uses different engines and was scheduled awhile back.
Second, not sure what your point is with the Russian launch. It uses different engines and was scheduled awhile back.
Not the rocket, the engines. And yes, they are decades old. The project that produced the NK-33 engines was abandoned i Soviet in 1974, so they are at least 40 years old. Aerojet bought a stockpile of them in the 90's.
Specific impulse is basically an efficiency measure, like mpg for cars. The higher it is, the more efficient the rocket engine is.
SpaceX's Merlin 1d has a thrust-to-weight ratio (twr) of 150, and a specific impulse (I_sp) at sea level of 2.73 km/s. I doubt this was an option for orbital sciences to use in their rockets.
The NK33, which is the soviet engine that was used, has a twr of 137 and an I_sp at sea level of 2.91 km/s.
The atlas V rockets by boeing and lockheed use an rd180, also russian built btw, which has a twr of 78.44 and an I_sp at sea level of 3.05 km/s.
The delta IV rockets by boeing us an rs68 or rs68a have a twr of 51.2 and an I_sp of 3.58 km/s. I'm not sure if these are available for commercial use, though, since boeing shut down the commercial delta IV launch program. The US military still uses them though, so they are still being produced. Also, these use liquid hydrogen instead of RP1 (rocket grade kerosine) like all the rest of the engines here.
The Saturn V used five F1 engines (also 1960s tech, but no longer available). Each of those have a twr of 82.27 and an I_sp of 2.58 km/s.