I was listening to NPR on the way home last week, and ISTR them saying that the engines Spacex uses are from the '60s. Paraphrasing: ‘Not 1960s technology; they were built in the 1960s.’
A cursory search does not support that statement. What’s the straight dope?
IIRC it was not about SpaceX. The engines, Russian built NK-33s, were used in Antares US launch vehicles from Orbital Sciences.
The straight dope is that the statement is false. Are you asking why anyone would think so?
That fits. When the Soviet N-1 moonshot program was cancelled, there were a bunch of engines left over that were later sold.
Thank you.
Am I asking why I am asking why anyone would think it’s true? I’m asking because it was mentioned in the story. NPR is usually good at fact-checking. It sounded odd to me. But I tend to concentrate more on my driving than to entertainment, so I asked to see if what I thought I heard was correct. jasg supplied the information.
The straight dope is a big nope. SpaceX has their own engines. But NASA’s SLS is supposed to reuse shuttle engines from the 80s.
Actually, I mis-remembered the recent NPR piece. It did not have to do with Antares. It mentions the current Soyuz launch vehicles - it was mentioned along with SpaceX Heavy, so easy to conflate.
About the only connection with the 60’s is that a core design element of the Merlin engine is that it uses a pintle design combustion chamber. This design was pioneered on the lunar module descent engine, and was a key part of the LM engine’s ability to throttle down to quite low powers.
As noted above, the commentary was clearly confusing SpaceX with Orbital Sciences.
Rocketdyne have started production of new RS-25 engines (aka SSME) in a slightly tweaked form for SLS. They will however use some old SSMEs as well.
As far as I know, the Saturn V, used in Apollo missions in 1968 and 1969, was the most advanced/powerful rocket of the sixties. SpaceX uses the “Falcon Heavy”, which is far more advanced than the Saturn V in terms of weight and efficiency.
The Saturn V is by far the most powerful rocket ever made. The Falcon Heavy is the most powerful rocket platform currently operating, but it is no match for the Saturn V. The upcoming NASA SLS will give the Saturn V a run for its money.
None of that has anything to do with the leftover NK-33 engines used on the Antares. (They are excellent engines, BTW. The failure of the N1 rocket was not because the engines were bad - everything else was.)
Although the original Merlin 1A/B engine used a direct injection pintle valve to mix and inject fuel and oxidizer directly into the the combustion chamber akin to the Lunar Module Descent Engine (although with a heritage arguably more derived from the TRW Low Cost Pintle Engine which SpaceX VP of Propulsion Tom Mueller had previously worked on) but the current Merlin 1D uses a pintle valve an injector into a premix chamber before being blown into the combustion chamber, so it isn’t really a ‘pintle injector engine’. The engines are, of course, new production using modern materials and fabrication methods.
The NK-33 (ground stage) and NK-43 (high altitide/vacuum) engines are fantastic engines with very high build quality, and have been proposed for use by a number of commercial efforts including the Kistler K-1 and used on the Soyuz-2-1v. Unfortunately, they’re also an all-welded design that is difficult to fully inspect and impossible to disassemble, and despite being in controlled storage started to display aging problems that lead to two static fire test failures prior to the Antares catastrophic failure at MARS. The NK-33/43 does use something similar to a pintle injector but has no design heritage or shares and components with the SpaceX Merlin engine.
Stranger
Somewhat related: There are several examples of Cold War missile components repurposed for space flight on this page at that other Q&A site.
we were doing that even during the Cold War; Redstone, Atlas, and Titan all started out as ballistic missiles.
Since SpaceX is a private company, they’re not obliged to release data, so I’m not sure how reliable the empty weight numbers are. However I’ve seen estimates the empty mass of all Falcon Heavy stages might be 124,000 pounds, and the fully-fueled mass about 306,000 pounds. That would put the structural mass fraction at about 4% which is really good. The Saturn V was probably 5% or higher. Likewise the Saturn V mass ratio was 23.1. I don’t know the Falcon Heavy mass ratio but it was probably higher, hence more efficient. Elon Musk has said the outboard Falcon Heavy boosters have a 30:1 mass ratio, which if true is amazing.
OTOH the Saturn V if operational today could lift an entire fully-fueled Falcon Heavy 2nd stage plus all its payload into orbit. The Saturn V could send more payload all the way to the moon than the Falcon Heavy could even lift into earth orbit.
Although never used for a Mars mission, the Saturn V could send more payload to Mars than the regular Falcon 9 could lift into low earth orbit.
It’s astonishing how truly gigantic those things were.
If you are talking about the F-1 engine, I’ve climbed inside of one and put my entire torso into the combustion chamber. But it is still dwarfed by the Sea Dragon.
Stranger
Not quite true. The FH can put 63 t into LEO. The S-V could put 41 t on trans-lunar injection.
That said, the S-V does better relative to the FH as you get further out (Moon, Mars, etc.). This is because of the higher number of stages (3 vs. 2) and the upper stages using hydrogen (“high energy”) propellant.
FH is a great vehicle, but if it’s to be used for interplanetary missions it’ll be best to use a kick stage of some kind (solid or liquid storable propellant). It’s at its most efficient to LEO.
Others have correctly pointed out that they were referring to the Orbital Sciences Antares vehicle, not SpaceX. The only SpaceX connection is that Musk did some trash talking of Antares in this Wired interview:
A little rude, but he wasn’t wrong (well, I’m not sure that it was precisely in Siberia, but it was a nearly forgotten warehouse in Russia).
Actively hidden and then nearly forgotten ?
The Soviet high command had ordered all work on the N-1 moonshot, including the NK-33 engines to be destroyed when the moon shot was given up.
A bureaucrat disobeyed and had the engines hidden/stored away.
And Antares no longer uses the NK-33. The Soyus 2.1v is the only one which does.
According to the Apollo 17 Flight Evaluation Report, the total mass injected to a lunar trajectory was 144,765 pounds (72.4 tons, or 65,664 kg). This is by actual instrumentation, not a spec: Apollo 17 Flight Journal - Mission Documents
Some of that mass was the depleted S-IVB 3rd stage, but you could argue that was a type of payload since it protected and housed the LM, plus it was steered to strike the moon for seismographic studies.
OTOH if you exclude the S-IVB, the total Apollo 17 spacecraft mass placed on lunar trajectory was 107,165 pounds (53.6 tons, 48,609 kg).
These areas are tricky because they involve how “payload” is defined, and for what purpose. Launch vehicle manufacturers are often not precise in their public information about how they define useful payload. For example SpaceX states Falcon Heavy has an LEO payload of 140,660 lb. But is the total useful payload? Does it include the fairing, or payload attachment fittings? They don’t say: http://www.spacex.com/falcon-heavy
The Saturn V LEO useful payload was 310,000 lbs (155 tons, 140,613 kg) – provided we denote that as applying to a lunar mission only. That was a fully functional, useful LEO payload for that mission class, since achieving the mission required putting that much “mission useful” mass in LEO.
The heaviest payload (functional or not) that any Saturn V delivered to orbit was Skylab (SA-513), which injected to LEO the entire orbital workshop plus the empty S-II 2nd stage. This was 325,247 lbs (162.6 tons, 147,529 kg). If we subtract the depleted S-II 2nd stage from this, the total useful LEO mass for the Skylab mission was about 239,247 lbs (120 tons, 108520 kg).
When the Saturn program was shut down they had already ground-tested the uprated F-1A engine which supposedly would have boosted Saturn V payload by roughly 10-15%, although those were never flown.
By contrast the SLS booster will have an LEO payload of 154,000 lbs (77 tons, 69,853 kg) in the Block I config, Block IB will be 232,000 lbs (116 tons, 105,233 kg), and Block II 286,000 lbs (143 tons, 129,727 kg). So even if it is built, depending on how payloads are counted the Block II SLS might not equal the Saturn V’s LEO payload: Space Launch System - Wikipedia
The SpaceX “BFR” will supposedly have an LEO payload of 550,000 lbs (275 tons, 249,475 kg) in the expendable mode and 330,000 lbs in the reusable mode. If achieved that, it would be very impressive. A reusable vehicle with the payload capacity of a Saturn V: SpaceX Starship - Wikipedia