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I am aware that the Saturn V is the largest rocket ever built and was capable of lifting more weight into space than anything that exists today. Modern rockets often carry several satellites up at once that together make up its full payload.

What I am wondering is: what is the largest single object ever lifted into space and what is its weight. Let's assume for this question that the LEM/CM or similar combinations are single multistage vehicles. Is the LEM/CM the largest yet, or is there something else?

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    $\begingroup$ For the Apollo missions, the 3rd stage reached Earth orbit along with the LM (when present) and CSM (command and service module). $\endgroup$ – Keith Thompson Jan 22 '16 at 21:33
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Depending on your definitions, the contenders seem to be the US Space Shuttle, Buran, Apollo 17, or Skylab.

Apollo 17 + S-IVB translunar     143 t?
STS, maximum payload             115 t
Discovery STS-82                 106 t
STS, no payload                   90 t
Buran + payload                   87 t?
Polyus                            80 t?
Skylab                            77 t
Buran, no payload                 75 t? 
Apollo 17 CSM/LM                  47 t

Skylab was 77 tons, launched as a single payload on a Saturn V (in fact, the station was converted from a Saturn V third stage).

The Apollo CM/LM stack was under 45 tons, but for the lunar missions, in low Earth orbit it remained attached to the Saturn's S-IVB third stage, which provided the fuel and engine for the translunar injection burn. The S-IVB burned a small amount of its fuel to get into LEO, but that left the combined translunar spacecraft massing over 115 tons.

The Apollos grew slightly in weight over the course of the program, as the launcher engines were uprated, confidence in safety margins improved, and more equipment was brought along. Apollo 16 and 17 were the heaviest, with 16 weighing a little more at launch, and 17 a little more in LEO (having used a bit less fuel getting there). Adding up the launch weights of components listed in Apollo By The Numbers, then subtracting the LES and the fuel used in the initial third-stage burn suggests an orbital mass over 140 tons.

The Space Shuttle orbiter masses over 68 tons dry, and carries a payload of up to 25 tons; its maximum takeoff weight ranged as high as 115 tons. I found a source giving Discovery's orbital mass as 106 tons for the STS-82 mission. As with the S-IVB, the orbiter is ambiguously part launcher and part payload.

The Soviet Energia booster was second to the Saturn V for payload-to-LEO, with approximately 100-ton capability. It flew twice: once with the Polyus payload described in Puffin's answer, once with the Buran spaceplane. Astronautix manages to give two very different weight figures for Buran on a single page. It's either a little lighter or a little heavier than STS.

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  • $\begingroup$ Was skylab in its entirety, launched as a single payload? $\endgroup$ – Octopus Jan 22 '16 at 21:28
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    $\begingroup$ So the possible candidates for the heaviest single object are: Apollo 9 through 17 (all the missions that launched a Lunar Module into Earth orbit) and Skylab 1. I can guess that Skylab was lighter than the Apollos (no LM, SM, or CM), but I'm not sure; the extra equipment might make up for that. Interesting question. $\endgroup$ – Keith Thompson Jan 22 '16 at 21:32
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    $\begingroup$ Good grief, I forgot how heavy STS was. $\endgroup$ – Russell Borogove Jan 22 '16 at 23:25
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    $\begingroup$ I'm not claiming it as the heaviest; that was just the only total mass to orbit figure I found. $\endgroup$ – Russell Borogove Jan 23 '16 at 1:44
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    $\begingroup$ WP says '92s payload was 9.5t? This is why we can't have nice things. $\endgroup$ – Russell Borogove Jan 23 '16 at 1:49
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Following the theme of "depending on your definitions" one could also consider the Polyus spacecraft launched in 1987. The mass of the spacecraft was 80 tonnes.

Thoughts about definitions:

  • slightly heavier then Skylab, less than the SIVB/LM/CSM stack
  • it didn't get to a stable orbit, perhaps to 155km.

The Energia vehicle functioned correctly and the Polyus separated correctly. However the mission plan called for the Polyus to complete the final orbit insertion itself, which didn't happen due to a fault in Polyus itself and it re-entered into the South Pacific.

enter image description here

The image is from here

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    $\begingroup$ "Polyus spun a full 360 degrees instead of the planned 180 degrees" ... "had not been rigorously tested due to the rushed production schedule." D'oh! $\endgroup$ – Octopus Jan 22 '16 at 22:34
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    $\begingroup$ @Octopus: The hazards of many of the Russian space vehicles... $\endgroup$ – PearsonArtPhoto Jan 23 '16 at 0:20
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    $\begingroup$ Polyus had a mass of around 80 metric tonnes, but this was at launch. The Energia launch vehicle relied on Polyus to perform its own LEO insertion. Had it flown as intended, the craft would have needed to burn some of its 80 tonne mass in propellant before reaching orbit. Skylab's mass on the ground included aerodynamic fairings and support structure that raised the total mass to just under 92 tonnes, after which the OWS would detach and jettison its nose fairing for a final 77 tonne mass. Polyus also had an aerodynamic fairing that would have been jettisoned, lowering mass further. $\endgroup$ – Alastair Haslam Dec 9 '18 at 16:14
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I have interpreted this question regarding two metrics: usable payload mass to orbit, and total injected mass to orbit – where the latter includes inert stages after burnout.

The highest usable payload mass to Low Earth Orbit goes to the three-stage Saturn V SA-512 vehicle used for Apollo 17. Apollo Project: Exploring the Moon by Robert Godwin gives the mass placed in a 171.3 x 168.9km earth orbit as 311,151lb or 141,136kg. None of the Apollo lunar flights lofted more mass to LEO, although Apollo 16’s SA-511 vehicle propelled a slightly greater payload to TLI (48,617kg vs 48,609kg, where the payload includes the CSM, LM and SLA).

The Saturn V lunar booster is an odd case when it comes to LEO payload. Notably, the LEO payload is the same as the total injected mass. However, the third stage qualifies as part of the payload as it is absolutely necessary for its mission of propelling humans and their spacecraft to the moon.

So, a three-stage Saturn V is not a LEO-optimised vehicle – but a two-stage variant is. The Saturn V SA-513 used to launch the Skylab OWS shows an even greater total injected mass:

http://forum.nasaspaceflight.com/index.php?topic=12519.20 Provides expected masses.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730025115.pdf Provides expected and actual masses from the flight.

  • Skylab OWS = 88,497kg
  • S-II/OWS Interstage = 3,453kg
  • Dry S-II Stage = 36,654kg
  • LOX residuals = 8,324kg
  • LH2 residuals = 2,790kg
  • S-II other = 2,827kg
  • S-IC/S-II Interstage = 4,986kg

The total mass to a 434 x 442km orbit at 50 degrees inclination is given as 147,531kg. Note that the S-IC/S-II interstage failed to separate after being damaged by debris falling off the OWS during the S-IC burn, and yet was still carried all the way to orbit. MSFC’s Flight Evaluation Report for SA-513 from August 1973 lists the optimal calculated total injected mass as 319,129lb (144,755kg), but this did not account for the S-II interstage failing to separate or, funnily enough, overperformance of the S-IC stage that resulted in 3.9% greater impulse than expected from the first stage.

Discounting the S-II dry mass, propellant and all other stage accessories the SA-513 vehicle’s two stages delivered 91,950kg in the form of Skylab, its fairing and its support structure. Including the S-IC/S-II interstage which was unnecessarily dragged to orbit, this would increase to 96,936kg but is otherwise irrelevant.

Therefore, the record for the greatest total injected mass to Low Earth Orbit by a single launch vehicle is 147,531kg and belongs to two-stage Skylab-1 Saturn V SA-513. This mass was placed into a 434 x 442km orbit at 50 degrees inclination. Of this, 91,950kg constituted the actual payload, while the remaining mass constituted the inert second stage, residual propellant and other accessories.

The record for the greatest functional payload mass to Low Earth Orbit by a single launch vehicle is 141,136kg and belongs to the three-stage Apollo 17 Saturn V SA-512. This mass was placed into a 171.3 x 168.9km orbit at 28.5 degrees inclination. Of this, 48,609kg constituted the lunar spacecraft payload while the remaining mass constituted the partially fuelled transfer stage required for the lunar mission.

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