4 ms·

I think you're confusing mass of the payload with something else. Mass of the payload to LEO is just how much mass is brought to LEO. According to "Alternatives

I think you're confusing mass of the payload with something else. Mass of the payload to LEO is just how much mass is brought to LEO. According to "Alternatives for Future U.S. Space-Launch Capabilities" [0], the Saturn V did in fact bring 140 tons to LEO... [0] https://www.cbo.gov/publication/18196 https://www.cbo.gov/publication/18196

avmich 6y ago
I think people are confusing the mass which appears on orbit with payload. Payload is (as meant when the word "payload" was created) rather the goal; in case of Saturn V it was Apollo stack which needed to be launched to the Moon. Similarly, in Space Shuttle case payload is something which is in the shuttle trunk; that's why typically a shuttle flies. Illustration for why 140 tons isn't the payload of Saturn V is that Saturn V wasn't able, or designed, to launch arbitrary 140 tons to LEO, and Skylab is a implicit confirmation of that. The definition of payload to LEO in case of higher-than-LEO missions can include booster stage and fuel, but then we have another strange case of Shuttle with IUS - the payload could fly higher, and was rather small, yet we don't consider Orbiter's mass as part of LEO payload in this case. Since, as another consideration, we usually consider Saturn V as a 3-staged rocket, not a 2-staged (as flew with Skylab) with a space booster stage which is used for LEO insertion as well as for subsequent translunar injection, it would be logical not to include 3rd Saturn's stage into LEO payload. Then Saturn V LEO payload becomes too small to be meaningful (TLI requires a lot of fuel). It would be better - here - to consider Space Shuttle LEO payload to include Orbiter's mass - that justifies large liftoff weight. As for what's Saturn V LEO payload, this question is better be met with clarifications.
avmich 6y ago
From https://www.cbo.gov/publication/18196 https://www.cbo.gov/publication/18196, the link above: "The payload of 140 metric tons is derived from weight data pro-vided in Richard W. Orloff, Apollo by the Numbers: A Statistical Reference, NASA SP-2000-4029 (National Aeronautics and Space Administration, updated September 27, 2005), available at http://history.nasa.gov/SP-4029/SP-4029.htm http://history.nasa.gov/SP-4029/SP-4029.htm. In that reference, 140 mt is the weight of the Apollo 17 command-and-service modules, the lunar module, the spacecraft/lunar module adapter, the instrument unit, and the S-IVB stage (the third stage of the Saturn V), including the fuel remaining in that stage needed to propel the Apollo command-and-service modules and lunar module from low earth orbit to the moon." So this number includes the S-IVB stage and unspent fuel. Which ought to raise the question of the definition of the payload - we don't usually consider launcher's parts among payload mass. > Mass of the payload to LEO is just how much mass is brought to LEO. No, it's usually not that simple - Space Shuttle here doesn't include Orbiter's mass (I think it's a mistake), Sputnik payload didn't include R-7 second stage (I think it's right), Energia doesn't have 0 LEO payload even though it releases the payload below LEO (I think this definition is also more meaningful).

avmich 6y ago

I think people are confusing the mass which appears on orbit with payload. Payload is (as meant when the word "payload" was created) rather the goal; in case of Saturn V it was Apollo stack which needed to be launched to the Moon. Similarly, in Space Shuttle case payload is something which is in the shuttle trunk; that's why typically a shuttle flies. Illustration for why 140 tons isn't the payload of Saturn V is that Saturn V wasn't able, or designed, to launch arbitrary 140 tons to LEO, and Skylab is a implicit confirmation of that. The definition of payload to LEO in case of higher-than-LEO missions can include booster stage and fuel, but then we have another strange case of Shuttle with IUS - the payload could fly higher, and was rather small, yet we don't consider Orbiter's mass as part of LEO payload in this case. Since, as another consideration, we usually consider Saturn V as a 3-staged rocket, not a 2-staged (as flew with Skylab) with a space booster stage which is used for LEO insertion as well as for subsequent translunar injection, it would be logical not to include 3rd Saturn's stage into LEO payload. Then Saturn V LEO payload becomes too small to be meaningful (TLI requires a lot of fuel). It would be better - here - to consider Space Shuttle LEO payload to include Orbiter's mass - that justifies large liftoff weight. As for what's Saturn V LEO payload, this question is better be met with clarifications.

avmich 6y ago

From https://www.cbo.gov/publication/18196 https://www.cbo.gov/publication/18196, the link above: "The payload of 140 metric tons is derived from weight data pro-vided in Richard W. Orloff, Apollo by the Numbers: A Statistical Reference, NASA SP-2000-4029 (National Aeronautics and Space Administration, updated September 27, 2005), available at http://history.nasa.gov/SP-4029/SP-4029.htm http://history.nasa.gov/SP-4029/SP-4029.htm. In that reference, 140 mt is the weight of the Apollo 17 command-and-service modules, the lunar module, the spacecraft/lunar module adapter, the instrument unit, and the S-IVB stage (the third stage of the Saturn V), including the fuel remaining in that stage needed to propel the Apollo command-and-service modules and lunar module from low earth orbit to the moon." So this number includes the S-IVB stage and unspent fuel. Which ought to raise the question of the definition of the payload - we don't usually consider launcher's parts among payload mass. > Mass of the payload to LEO is just how much mass is brought to LEO. No, it's usually not that simple - Space Shuttle here doesn't include Orbiter's mass (I think it's a mistake), Sputnik payload didn't include R-7 second stage (I think it's right), Energia doesn't have 0 LEO payload even though it releases the payload below LEO (I think this definition is also more meaningful).