6 ms·

dumb question - why are we using Saturn V derived rockets? afaik none of these new rockets can match its max payload

mlindner 5y ago
I assume you typoed and meant to ask “why aren’t” instead. We aren’t because the Saturn V moon rocket (and related projects) were consuming over 4% of the US government’s budget, way more than even the SLS and definitely more than the Falcon Heavy.
meepmorp 5y ago
Starship exceeds Saturn V’s lift capacity.
- lmilcin 5y ago
  Not true. Saturn V's lift to LEO was 120-140 tonnes (https://en.wikipedia.org/wiki/Saturn_V https://en.wikipedia.org/wiki/Saturn_V) while SpaceX claims Starship's is "over" 100 tonnes (https://www.spacex.com/media/starship_users_guide_v1.pdf https://www.spacex.com/media/starship_users_guide_v1.pdf).
  - ceejayoz 5y ago
    It exceeds Saturn V on the second launch that day. ;-)
    - lmilcin 5y ago
      Well, if you have a 140t payload it doesn't matter how many 100t payloads you can lift per day, it just isn't going to lift it. On the other hand, obviously, payloads are planned for the rocket they are going to be lifted by, so most likely somebody will set constraints on their project to either have smaller payload or split it into parts.
      - ceejayoz 5y ago
        Right; I think Starship, if it pans out, is going to entirely change how we plan, build, and carry out space missions, both manned and unmanned.
      - SAI_Peregrinus 5y ago
        It's also possible whoever has such a large payload might want their own second stage & a fairing, instead of Starship. A single-use stage (no reserve fuel) with no re-entry needs could be a lot lighter than Starship, though vastly more expensive. That might be worth it for some payloads. Super Heavy is planned to be a ridiculously powerful booster. I doubt that will happen though. It's far more likely in-orbit assembly and orbital refueling will progress dramatically as launch costs drop, and anyone with such a payload would find a way to design it for such assembly.
    - zzt123 5y ago
      Don’t final inspections with payload attached by itself take more than a day? Or is that going to be a relic of the past?
      - ceejayoz 5y ago
        I doubt anyone knows for sure at this point, but I'd imagine the goal is something more akin to loading cargo into the belly of an airliner; consistently sized modules with standardized attachments for power etc.
      - dredmorbius 5y ago
        Even given a few weeks, the relaunch of an Saturn V will be a bit rough.
  - avmich 5y ago
    Starship brings any 100 tonnes to orbit, while of Saturn V's 120+ tons a half constitutes the 3rd stage with unspent fuel. So it's less of payload per ce for Saturn V compared to Starship. On the other hand, Starship didn't fly to orbit yet. We'll see better how it goes when it does. And we can't fly Saturn V now anyway. And Starship - even if supposedly with lower payload - promises to be much cheaper. And...
    - bryanlarsen 5y ago
      In Skylab mode it was pure payload.
      - avmich 5y ago
        Which weighted less than 80 tons - much less than what other superheavy rockets are bringing to LEO - Energiya, SLS, BFR...
  - midasuni 5y ago
    That’s looking at a single launch and neglecting the refuel ability.
- scrumbledober 5y ago
  And will be able to refuel in orbit
skykooler 5y ago
We don't have the infrastructure to build them anymore, and a lot of the design wasn't captured in the blueprints because things were tweaked by hand to make them work. We could build something with Saturn V-like performance, but it would be a new rocket, not just resuming production of the older line.
bryanlarsen 5y ago
That was seriously considered. It was rejected because schematics consist only a small portion of the knowledge necessary to build a rocket, most of the rest had been lost to time. A massive amount of redesign was required to build the shuttle derived SLS, deriving from Saturn would have been worse. But the real reason was that deriving from Shuttle kept those employees employed. SLS has never been a rocket program, it's always been a pork program. SpaceX's Starship has twice the thrust of Saturn, so could be tweaked to send more payload by sacrificing reusability. But they have an even better plan -- refueling allows massive payloads.
- lmilcin 5y ago
  In particular, all Saturn V engines were completely hand-built and the process was not documented. A lot of very fine craftsmanship went into that that we can't replicate today.
  - renewiltord 5y ago
    Seems like that situation where the first engineer builds an inscrutably clever codebase. Lots of fine craftsmanship indeed.
  - akiselev 5y ago
    Nitpick: we can replicate it, it's not like we've technologically regressed. We're just not willing to spend the money - at it's peak NASA's budget was ~4.5% of federal spending when the Saturn V was designed (it's now only 0.5%).
    - KineticLensman 5y ago
      > Nitpick: we can replicate it, it's not like we've technologically regressed. Saturn's materials and computer technology are more than 50 years old. Not only would we have to want to recreate this historic technology, we would have to recreate the knowledge, skills and competencies of the experienced craftsmen that used it, across the massive supply chain, as well as the tooling required.
    - 5y ago
Tempest1981 5y ago
Looking at the "LEO Payload" column here: https://en.wikipedia.org/wiki/Super_heavy-lift_launch_vehicle https://en.wikipedia.org/wiki/Super_heavy-lift_launch_vehicl... Saturn V: 310,000 lb SLS: 209,000 lb planned Falcon Heavy: 126,000-141,000 lb Starship: 220,000–330,000 lb planned
- ceejayoz 5y ago
  Of course, the benefit of Starship is that it can (in theory) do that several times a day.
  - fnord77 5y ago
    wasn't that the promise with the space shuttle, too?
    - eloff 5y ago
      Maybe at one point, but the final design did not allow rapid turnaround. Starship could actually do it the way is being designed. They have a good shot at pulling it off.

I assume you typoed and meant to ask “why aren’t” instead. We aren’t because the Saturn V moon rocket (and related projects) were consuming over 4% of the US government’s budget, way more than even the SLS and definitely more than the Falcon Heavy.

meepmorp 5y ago

Starship exceeds Saturn V’s lift capacity.

lmilcin 5y ago
Not true. Saturn V's lift to LEO was 120-140 tonnes (https://en.wikipedia.org/wiki/Saturn_V https://en.wikipedia.org/wiki/Saturn_V) while SpaceX claims Starship's is "over" 100 tonnes (https://www.spacex.com/media/starship_users_guide_v1.pdf https://www.spacex.com/media/starship_users_guide_v1.pdf).
- ceejayoz 5y ago
  It exceeds Saturn V on the second launch that day. ;-)
  - lmilcin 5y ago
    Well, if you have a 140t payload it doesn't matter how many 100t payloads you can lift per day, it just isn't going to lift it. On the other hand, obviously, payloads are planned for the rocket they are going to be lifted by, so most likely somebody will set constraints on their project to either have smaller payload or split it into parts.
    - ceejayoz 5y ago
      Right; I think Starship, if it pans out, is going to entirely change how we plan, build, and carry out space missions, both manned and unmanned.
    - SAI_Peregrinus 5y ago
      It's also possible whoever has such a large payload might want their own second stage & a fairing, instead of Starship. A single-use stage (no reserve fuel) with no re-entry needs could be a lot lighter than Starship, though vastly more expensive. That might be worth it for some payloads. Super Heavy is planned to be a ridiculously powerful booster. I doubt that will happen though. It's far more likely in-orbit assembly and orbital refueling will progress dramatically as launch costs drop, and anyone with such a payload would find a way to design it for such assembly.
  - zzt123 5y ago
    Don’t final inspections with payload attached by itself take more than a day? Or is that going to be a relic of the past?
    - ceejayoz 5y ago
      I doubt anyone knows for sure at this point, but I'd imagine the goal is something more akin to loading cargo into the belly of an airliner; consistently sized modules with standardized attachments for power etc.
    - dredmorbius 5y ago
      Even given a few weeks, the relaunch of an Saturn V will be a bit rough.
- avmich 5y ago
  Starship brings any 100 tonnes to orbit, while of Saturn V's 120+ tons a half constitutes the 3rd stage with unspent fuel. So it's less of payload per ce for Saturn V compared to Starship. On the other hand, Starship didn't fly to orbit yet. We'll see better how it goes when it does. And we can't fly Saturn V now anyway. And Starship - even if supposedly with lower payload - promises to be much cheaper. And...
  - bryanlarsen 5y ago
    In Skylab mode it was pure payload.
    - avmich 5y ago
      Which weighted less than 80 tons - much less than what other superheavy rockets are bringing to LEO - Energiya, SLS, BFR...
- midasuni 5y ago
  That’s looking at a single launch and neglecting the refuel ability.
scrumbledober 5y ago
And will be able to refuel in orbit

skykooler 5y ago

We don't have the infrastructure to build them anymore, and a lot of the design wasn't captured in the blueprints because things were tweaked by hand to make them work. We could build something with Saturn V-like performance, but it would be a new rocket, not just resuming production of the older line.

bryanlarsen 5y ago

That was seriously considered. It was rejected because schematics consist only a small portion of the knowledge necessary to build a rocket, most of the rest had been lost to time. A massive amount of redesign was required to build the shuttle derived SLS, deriving from Saturn would have been worse. But the real reason was that deriving from Shuttle kept those employees employed. SLS has never been a rocket program, it's always been a pork program. SpaceX's Starship has twice the thrust of Saturn, so could be tweaked to send more payload by sacrificing reusability. But they have an even better plan -- refueling allows massive payloads.

lmilcin 5y ago
In particular, all Saturn V engines were completely hand-built and the process was not documented. A lot of very fine craftsmanship went into that that we can't replicate today.
- renewiltord 5y ago
  Seems like that situation where the first engineer builds an inscrutably clever codebase. Lots of fine craftsmanship indeed.
- akiselev 5y ago
  Nitpick: we can replicate it, it's not like we've technologically regressed. We're just not willing to spend the money - at it's peak NASA's budget was ~4.5% of federal spending when the Saturn V was designed (it's now only 0.5%).
  - KineticLensman 5y ago
    > Nitpick: we can replicate it, it's not like we've technologically regressed. Saturn's materials and computer technology are more than 50 years old. Not only would we have to want to recreate this historic technology, we would have to recreate the knowledge, skills and competencies of the experienced craftsmen that used it, across the massive supply chain, as well as the tooling required.
  - 5y ago

Tempest1981 5y ago

Looking at the "LEO Payload" column here: https://en.wikipedia.org/wiki/Super_heavy-lift_launch_vehicle https://en.wikipedia.org/wiki/Super_heavy-lift_launch_vehicl... Saturn V: 310,000 lb SLS: 209,000 lb planned Falcon Heavy: 126,000-141,000 lb Starship: 220,000–330,000 lb planned

ceejayoz 5y ago
Of course, the benefit of Starship is that it can (in theory) do that several times a day.
- fnord77 5y ago
  wasn't that the promise with the space shuttle, too?
  - eloff 5y ago
    Maybe at one point, but the final design did not allow rapid turnaround. Starship could actually do it the way is being designed. They have a good shot at pulling it off.