# Spacex engines **URL:** \ **Category:** Factual Questions\ **Created:** [February 14, 2018, 4:24pm UTC](https://boards.straightdope.com/t/spacex-engines/808833 "2018-02-14T16:24:01Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [February 14, 2018, 4:24pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/1 "2018-02-14T16:24:01Z")
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? ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [February 14, 2018, 4:33pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/2 "2018-02-14T16:33:28Z")
IIRC it was not about SpaceX. The engines, Russian built NK-33s, were used in Antares US launch vehicles from Orbital Sciences. ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [February 14, 2018, 4:33pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/3 "2018-02-14T16:33:36Z")
The straight dope is that the statement is false. Are you asking why anyone would think so? ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [February 14, 2018, 4:36pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/4 "2018-02-14T16:36:22Z")
> [@jasg](#): > > IIRC it was not about SpaceX. The engines, Russian built NK-33s, were used in Antares US launch vehicles from Orbital Sciences. That fits. When the Soviet N-1 moonshot program was cancelled, there were [a bunch of engines left over](https://en.wikipedia.org/wiki/NK-33) that were later sold. > [@](#): > > About 60 engines survived in the “Forest of Engines”, as described by engineers on a trip to the warehouse. In the mid-1990s, Russia sold 36 engines to Aerojet General for $1.1 million each, shipping them to the company facility in Sacramento CA. During the engine test in Sacramento, the engine hit its specifications. Aerojet now had the proof they needed to sell the engines for the latest launch of satellites. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [February 14, 2018, 4:37pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/5 "2018-02-14T16:37:26Z")
> [@jasg](#): > > IIRC it was not about SpaceX. The engines, Russian built NK-33s, were used in Antares US launch vehicles from Orbital Sciences. Thank you. > [@ElvisL1ves](#): > > The straight dope is that the statement is false. Are you asking why anyone would think so? 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. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [February 14, 2018, 4:38pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/6 "2018-02-14T16:38:06Z")
The straight dope is a big nope. [SpaceX has their own engines](https://en.wikipedia.org/wiki/SpaceX_rocket_engines). But [NASA’s SLS is supposed to reuse shuttle engines from the 80s](https://en.wikipedia.org/wiki/Space_Shuttle_main_engine#Space_Launch_System). ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [February 14, 2018, 4:41pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/7 "2018-02-14T16:41:35Z")
> [@jasg](#): > > IIRC it was not about SpaceX. The engines, Russian built NK-33s, were used in Antares US launch vehicles from Orbital Sciences. Actually, I mis-remembered the [recent NPR](https://www.npr.org/2018/02/08/584335337/how-the-launch-of-spacexs-falcon-heavy-fits-into-the-companys-other-wordly-plans) 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. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [February 14, 2018, 4:43pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/8 "2018-02-14T16:43:53Z")
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. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [February 14, 2018, 4:56pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/9 "2018-02-14T16:56:58Z")
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. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [February 14, 2018, 6:08pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/10 "2018-02-14T18:08:39Z")
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.) ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 14, 2018, 7:28pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/11 "2018-02-14T19:28:10Z")
> [@Francis\_Vaughan](#): > > 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. 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. > [@friedo](#): > > 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.) 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 ---
**Author:** ![Heracles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heracles/32/487_2.png) [@Heracles](https://boards.straightdope.com/u/Heracles)\ **Post date:** [February 14, 2018, 8:38pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/12 "2018-02-14T20:38:24Z")
Somewhat related: There are several examples of Cold War missile components repurposed for space flight [on this page](https://space.stackexchange.com/questions/5322/were-decommissioned-cold-war-missiles-repurposed-for-peaceful-spaceflight) at _that other Q&A site_. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [February 14, 2018, 9:38pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/13 "2018-02-14T21:38:38Z")
> [@Heracles](#): > > Somewhat related: There are several examples of Cold War missile components repurposed for space flight [on this page](https://space.stackexchange.com/questions/5322/were-decommissioned-cold-war-missiles-repurposed-for-peaceful-spaceflight) 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. ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [February 14, 2018, 11:32pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/14 "2018-02-14T23:32:00Z")
> [@Jasmine](#): > > …SpaceX uses the “Falcon Heavy”, which is far more advanced than the Saturn V in terms of weight and efficiency. 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. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [February 15, 2018, 2:40am UTC](https://boards.straightdope.com/t/spacex-engines/808833/15 "2018-02-15T02:40:51Z")
It’s astonishing how truly gigantic those things were. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 15, 2018, 3:05am UTC](https://boards.straightdope.com/t/spacex-engines/808833/16 "2018-02-15T03:05:02Z")
> [@friedo](#): > > 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](http://www.astronautix.com/s/seadragon.html). Stranger ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [February 15, 2018, 4:21am UTC](https://boards.straightdope.com/t/spacex-engines/808833/17 "2018-02-15T04:21:29Z")
> [@joema](#): > > The Saturn V could send more payload all the way to the moon than the Falcon Heavy could even lift into earth orbit. 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. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [February 15, 2018, 4:34am UTC](https://boards.straightdope.com/t/spacex-engines/808833/18 "2018-02-15T04:34:00Z")
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](https://www.wired.com/2012/10/ff-elon-musk-qa/): > [@Elon Musk](#): > > One of our competitors, Orbital Sciences, has a contract to resupply the International Space Station, and their rocket honestly sounds like the punch line to a joke. 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. 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). ---
**Author:** ![barath\_s](https://avatars.discourse-cdn.com/v4/letter/b/90ced4/32.png) [@barath\_s](https://boards.straightdope.com/u/barath_s)\ **Post date:** [February 15, 2018, 10:00am UTC](https://boards.straightdope.com/t/spacex-engines/808833/19 "2018-02-15T10:00:36Z")
> [@Dr.Strangelove](#): > > 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. ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [February 15, 2018, 3:56pm UTC](https://boards.straightdope.com/t/spacex-engines/808833/20 "2018-02-15T15:56:08Z")
> [@Dr.Strangelove](#): > > Not quite true. The FH can put 63 t into LEO. The S-V could put 41 t on trans-lunar injection… 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](https://history.nasa.gov/afj/ap17fj/a17-documents.html) 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](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](https://en.wikipedia.org/wiki/Space_Launch_System) 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](https://en.wikipedia.org/wiki/BFR_(rocket)) [Next page](https://boards.straightdope.com/t/spacex-engines/808833.md?page=2)