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The Astrobotic team announced a while ago that they will launch their rovers on top of a Falcon 9. As I know the Saturn V rocket had a third-stage, which was used to redirect the spacecraft from Earth's orbit to the moon.

How will the Falcon 9 accomplish this? Will SpaceX use a third-stage? Or will they have enough fuel to use the second-stage to get the rovers to the moon?

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From Astrobotic's website, on the fifth slide, they state that Falcon 9 + Griffin can deliver 663kg to TLI (translunar injection), 515kg to Lunar orbit (althougth the specific operational parameters of this orbit are not stated), and 270kg to the Lunar surface.

Obviously, this is for payloads contracting the use of Astrobotic's Griffin platform as Falcon 9 can deliver far more to TLI than 663kg (should be a few thousand kg). This is confirmed in the Astrobotic Payload User's Guide (PDF warning), which goes into far more detail about the mission architecture:

Astrobotic’s 2015 mission explores a lunar skylight that may be an entrance to a subsurface cave network. A SPACEX Falcon 9, currently under contract, launches and performs trans-lunar injection. The spacecraft cruises for 4.5 days, orbits at 100KM, descends, and lands on the Moon 36 hours after local sunrise. A rover departs the lander to win the Google Lunar XPrize and explore the skylight, while the Griffin lander generates power and supports payload operations. During the night, Griffin and rover hibernate, then revive for several lunar days.

The situation appears similar to SpaceX's prior comsat launches. The second stage restarts to perform a burn which takes the payload into GTO (or in this case, TLI), and then the payload separates. From there, the payload operator is in control.

Also, for what it's worth, the Griffin lander has the following specifications:

  • Dry Mass: 535kg
  • Fuel Mass: 1685kg

This totals to 2220kg, which is in addition to the payloads flying on Griffin. This matches far more closely with F9's TLI payload specs.

Suffice to say, no, Falcon 9 does not, and cannot deliver the payloads directly to the lunar surface.

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