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https://en.wikipedia.org/wiki/BFR_(rocket) https://en.wikipedia.org/wiki/BFR_(rocket) https://en.wikipedia.org/wiki/Saturn_V https://en.wikipedia.org/wiki/Satur

https://en.wikipedia.org/wiki/BFR_(rocket) https://en.wikipedia.org/wiki/BFR_(rocket) https://en.wikipedia.org/wiki/Saturn_V https://en.wikipedia.org/wiki/Saturn_V You realize that BFR is much heavier than the Saturn V stack, right? The thrust means nothing. Look at the effective payload weight. Yes the thrust is higher, but it weighs nearly 1.5 times more so it can't haul as much payload. Notice how the payload to LEO is less than the Saturn V. I am not spreading misinformation. I'm here to educate.

mikeash 8y ago
For an apples to apples comparison, you need to include the BFS itself in the “mass to orbit” number. Or subtract the mass of Apollo from Saturn V’s.
- maxerickson 8y ago
  The payload is such an interesting comparison that there is a word for it. The wikipedia articles give 100,000 kg for the BFR and 140,000 kg for the Saturn V. For hundreds of missions, the BFR strategy of refueling to leave orbit probably makes sense, but it's pretty clear which rocket puts more payload in a 90 mile orbit, a very direct comparison of launch capability. And of course, BFR may exceed projections (or fail to meet them).
  - mikeash 8y ago
    Wikipedia’s number for the BFR is payload other than the BFS itself. BFR puts up a gigantic spaceship, and a huge payload inside it. Saturn V did not do this. Apollo (or Skylab) was the payload.
    - computerex 8y ago
      The BFS is part of the whole stack, it is the second stage. It is unclear because of lack of technical specification from SpaceX but at the moment it seems unlikely that the BFB will fly without the BFS. So you can't look at the BFS as a separate thing as you are implying, it is a core part of the architecture. It'd be like saying that the Saturn V can haul x amount of payload in addition to its second stage.
      - mikeash 8y ago
        You can’t ignore it either. The BFS isn’t a useless hunk of metal once it’s in orbit, it’s still very useful. Consider a past example. The Space Shuttle’s payload to orbit was many times smaller than Saturn V’s. Yet the Shuttle could do missions over two weeks long with seven crew, far more than Apollo could. How is that possible? Because the orbiter didn’t count as part of the “payload”. BFR is going to send 8 people on a trip around the moon. Saturn V couldn’t do that, even though it could orbit more “payload.” It all depends on the mission. If you just want to put satellites in orbit, Saturn V is more capable (ignoring costs). If you want to send people somewhere, BFR is way more capable. BFR can put a lot more mass into orbit, it’s just that a lot of that mass is taken up by mandatory stuff. If that stuff is useful for you then it should count. If it’s not then it shouldn’t. And that brings us back to my original point, way up there, that BFR is major overkill for a satellite launcher, but makes perfect sense for a Mars mission.
        maxerickson 8y ago
        The trip to the moon is great, but it's 2 launches.
        mikeash 8y ago
        Is it? The mission profile shown during the presentation makes no mention of that. It also shows only 30 minutes in orbit before the lunar injection burn, which wouldn’t be enough to refuel from a tanker.
        computerex 8y ago
        Saturn V and Apollo were designed for a very specific purpose. And so the CSM could only sustain the crew for the trip to the moon. The 310k lbs payload did not include the CSM and LEM. In theory the Saturn V booster could haul up a BFS style ship if such a thing existed.
        mikeash 8y ago
        “The 310k lbs payload did not include the CSM and LEM.” Are you saying the Saturn V was able to lift 310k lbs plus the CSM and LEM? I’m pretty sure that not true. Saturn V was a general purpose rocket. It wasn’t tied to Apollo, as evidenced by Skylab. It just worked out that nobody found a cost-effective use for it beyond Apollo and Skylab.
  - CydeWeys 8y ago
    And BFR will launch 100 Mg for a tiny fraction of the price of the 140 Mg that the Saturn V could do. Add to that the fact that the plan is for two BFRs to dock in LEO and shuttle across supplies and you end up with larger mission capacity, still at a fraction of the price. Reusability is the huge game-changer here. When you're reusable, the max payload per launch doesn't matter nearly as much since it's not a one-shot deal.
    - computerex 8y ago
      I have no stock in the proposed cost savings until it actually becomes a reality. What people don't realize is that reusability isn't as straightforward as SpaceX makes it seem. A used stage has to be taken apart, inspected and refurbished. It is unlikely that SpaceX saves any money on reusing their stages, they might even be losing money. https://spacenews.com/spacexs-reusable-falcon-9-what-are-the-real-cost-savings-for-customers/ https://spacenews.com/spacexs-reusable-falcon-9-what-are-the...
      - mikeash 8y ago
        They have stated that their very first reused booster cost less than half as much money to refurbish than it cost to build a new one. That was quite a while ago, with a much less advanced reusable design. The current version of the Falcon 9 incorporates lessons learned from tearing down and reflying the earlier units, so should be much cheaper. Even if you think there are no possible improvements, it can’t possibly get worse than a 50% savings. Unless you’re proposing that they’re lying out their asses?
      - greglindahl 8y ago
        The article you link is 2 years old. The price difference is now known: F9 to GTO is $50mm using a reused-and-recoverable booster, compared to the old list price of $62mm. The cost difference is fully known inside of SpaceX; their public statements disagree with your speculation.
tigershark 8y ago
You realise that the overwhelming majority of the weight in a rocket is fuel, right? The empty mass of the Saturn V first stage is 130000kg while its gross mass is 20 times more. Obviously a rocket designed to go to mars needs to carry much more fuel. The strength of a rocket is given by the lifting force that it can produce and 61.8MN of BFR is almost double the 35MN of Saturn V. And if we look at the second stages the 14MN of BFR are almost triple the 5.1MN of Saturn V. You are not educating at all, you are knowingly and deliberately spreading lies and misinformation. The pure and cold numbers that I posted instead are facts.
- computerex 8y ago
  Look buddy, you are wrong. No one looks at the thrust values to determine the strength of the rocket besides you. A rocket's job is to haul payload and so the strength of a rocket is determined by how much payload it can haul not max thrust values. As you can clearly see in this case, despite having more thrust the BFR can haul less payload to LEO than the Saturn V. All you did in your last comment is literally repeat what you said earlier. The "pure and cold numbers" you posted shows how ignorant you are about spaceflight. Come up with something original and present an argument for why the thrust is a better and more useful metric for measuring the strength of a rocket than its payload capacity.
  - tigershark 8y ago
    It's useless to discuss with you, you are just wasting my time. The numbers are there, the BFR lifting force is almost double Saturn V and the total mass that BFR is bringing in orbit is double the one that Saturn V brought in orbit. Please, continue with your non-sense if you like, I think that it's clear to everyone who is spreading mis-information and ignorance saying the BFR is only slightly more powerful than Saturn V.
    - computerex 8y ago
      I'm not the one spreading nonsense. You are wrong 100% and repeating yourself 3 times isn't going to change that. https://en.m.wikipedia.org/wiki/BFR_(rocket) https://en.m.wikipedia.org/wiki/BFR_(rocket) https://en.m.wikipedia.org/wiki/Saturn_V https://en.m.wikipedia.org/wiki/Saturn_V The number you are looking for is "payload to LEO". For Saturn that number is 310k lbs and for BFR it is 220k lbs. 310k is bigger than 220k.

mikeash 8y ago

For an apples to apples comparison, you need to include the BFS itself in the “mass to orbit” number. Or subtract the mass of Apollo from Saturn V’s.

maxerickson 8y ago
The payload is such an interesting comparison that there is a word for it. The wikipedia articles give 100,000 kg for the BFR and 140,000 kg for the Saturn V. For hundreds of missions, the BFR strategy of refueling to leave orbit probably makes sense, but it's pretty clear which rocket puts more payload in a 90 mile orbit, a very direct comparison of launch capability. And of course, BFR may exceed projections (or fail to meet them).
- mikeash 8y ago
  Wikipedia’s number for the BFR is payload other than the BFS itself. BFR puts up a gigantic spaceship, and a huge payload inside it. Saturn V did not do this. Apollo (or Skylab) was the payload.
  - computerex 8y ago
    The BFS is part of the whole stack, it is the second stage. It is unclear because of lack of technical specification from SpaceX but at the moment it seems unlikely that the BFB will fly without the BFS. So you can't look at the BFS as a separate thing as you are implying, it is a core part of the architecture. It'd be like saying that the Saturn V can haul x amount of payload in addition to its second stage.
    - mikeash 8y ago
      You can’t ignore it either. The BFS isn’t a useless hunk of metal once it’s in orbit, it’s still very useful. Consider a past example. The Space Shuttle’s payload to orbit was many times smaller than Saturn V’s. Yet the Shuttle could do missions over two weeks long with seven crew, far more than Apollo could. How is that possible? Because the orbiter didn’t count as part of the “payload”. BFR is going to send 8 people on a trip around the moon. Saturn V couldn’t do that, even though it could orbit more “payload.” It all depends on the mission. If you just want to put satellites in orbit, Saturn V is more capable (ignoring costs). If you want to send people somewhere, BFR is way more capable. BFR can put a lot more mass into orbit, it’s just that a lot of that mass is taken up by mandatory stuff. If that stuff is useful for you then it should count. If it’s not then it shouldn’t. And that brings us back to my original point, way up there, that BFR is major overkill for a satellite launcher, but makes perfect sense for a Mars mission.
      - maxerickson 8y ago
        The trip to the moon is great, but it's 2 launches.
        mikeash 8y ago
        Is it? The mission profile shown during the presentation makes no mention of that. It also shows only 30 minutes in orbit before the lunar injection burn, which wouldn’t be enough to refuel from a tanker.
      - computerex 8y ago
        Saturn V and Apollo were designed for a very specific purpose. And so the CSM could only sustain the crew for the trip to the moon. The 310k lbs payload did not include the CSM and LEM. In theory the Saturn V booster could haul up a BFS style ship if such a thing existed.
        mikeash 8y ago
        “The 310k lbs payload did not include the CSM and LEM.” Are you saying the Saturn V was able to lift 310k lbs plus the CSM and LEM? I’m pretty sure that not true. Saturn V was a general purpose rocket. It wasn’t tied to Apollo, as evidenced by Skylab. It just worked out that nobody found a cost-effective use for it beyond Apollo and Skylab.
- CydeWeys 8y ago
  And BFR will launch 100 Mg for a tiny fraction of the price of the 140 Mg that the Saturn V could do. Add to that the fact that the plan is for two BFRs to dock in LEO and shuttle across supplies and you end up with larger mission capacity, still at a fraction of the price. Reusability is the huge game-changer here. When you're reusable, the max payload per launch doesn't matter nearly as much since it's not a one-shot deal.
  - computerex 8y ago
    I have no stock in the proposed cost savings until it actually becomes a reality. What people don't realize is that reusability isn't as straightforward as SpaceX makes it seem. A used stage has to be taken apart, inspected and refurbished. It is unlikely that SpaceX saves any money on reusing their stages, they might even be losing money. https://spacenews.com/spacexs-reusable-falcon-9-what-are-the-real-cost-savings-for-customers/ https://spacenews.com/spacexs-reusable-falcon-9-what-are-the...
    - mikeash 8y ago
      They have stated that their very first reused booster cost less than half as much money to refurbish than it cost to build a new one. That was quite a while ago, with a much less advanced reusable design. The current version of the Falcon 9 incorporates lessons learned from tearing down and reflying the earlier units, so should be much cheaper. Even if you think there are no possible improvements, it can’t possibly get worse than a 50% savings. Unless you’re proposing that they’re lying out their asses?
    - greglindahl 8y ago
      The article you link is 2 years old. The price difference is now known: F9 to GTO is $50mm using a reused-and-recoverable booster, compared to the old list price of $62mm. The cost difference is fully known inside of SpaceX; their public statements disagree with your speculation.

tigershark 8y ago

You realise that the overwhelming majority of the weight in a rocket is fuel, right? The empty mass of the Saturn V first stage is 130000kg while its gross mass is 20 times more. Obviously a rocket designed to go to mars needs to carry much more fuel. The strength of a rocket is given by the lifting force that it can produce and 61.8MN of BFR is almost double the 35MN of Saturn V. And if we look at the second stages the 14MN of BFR are almost triple the 5.1MN of Saturn V. You are not educating at all, you are knowingly and deliberately spreading lies and misinformation. The pure and cold numbers that I posted instead are facts.

computerex 8y ago
Look buddy, you are wrong. No one looks at the thrust values to determine the strength of the rocket besides you. A rocket's job is to haul payload and so the strength of a rocket is determined by how much payload it can haul not max thrust values. As you can clearly see in this case, despite having more thrust the BFR can haul less payload to LEO than the Saturn V. All you did in your last comment is literally repeat what you said earlier. The "pure and cold numbers" you posted shows how ignorant you are about spaceflight. Come up with something original and present an argument for why the thrust is a better and more useful metric for measuring the strength of a rocket than its payload capacity.
- tigershark 8y ago
  It's useless to discuss with you, you are just wasting my time. The numbers are there, the BFR lifting force is almost double Saturn V and the total mass that BFR is bringing in orbit is double the one that Saturn V brought in orbit. Please, continue with your non-sense if you like, I think that it's clear to everyone who is spreading mis-information and ignorance saying the BFR is only slightly more powerful than Saturn V.
  - computerex 8y ago
    I'm not the one spreading nonsense. You are wrong 100% and repeating yourself 3 times isn't going to change that. https://en.m.wikipedia.org/wiki/BFR_(rocket) https://en.m.wikipedia.org/wiki/BFR_(rocket) https://en.m.wikipedia.org/wiki/Saturn_V https://en.m.wikipedia.org/wiki/Saturn_V The number you are looking for is "payload to LEO". For Saturn that number is 310k lbs and for BFR it is 220k lbs. 310k is bigger than 220k.