What dry mass could have soft-landed on the Moon if a Saturn V had been reconfigured to launch a robotic mission going entirely to the surface? Obviously, that wasn't possible at the time, but for a return to the Moon it might make a lot of sense.
Though there are no more Saturn Vs, if SpaceX produces their Mars Colonial Transporter design, Elon says it'll 'make the Apollo moon rocket look small'. So to mock-up large-scale missions to the Moon based on robotics, I'd like to base the payload on what a Saturn V could have done if it had been reconfigured with that in mind.
Here's what there is to work with:
- Lunar Modules - Ascent - 4800 kg (can add all that, nothing is ascending)
- Descent Module - 2000 kg dry mass, 8212 kg propellant,
- Command and Service Module - 11,900 kg dry mass, 16,900 kg fuel (these masses need to be combined to calculate what mass could be landed if there was only one engine system)
- Launch Escape System - 3600 kg (discarded soon after launch, so some portion of that can be added to payload to the Moon's surface)
So there are a few wrinkles here. What kind of mass savings could be gotten by combining the engines of the LEM and CSM and resizing for something that would land the resultant configuration on the surface? How much of the launch escape system can be regarded as extra payload mass to the Moon? I haven't found a figure for its mass, but would it be reasonable to tack on the mass of the Lunar Module Adapter?
A note - as this is about construction, I'm not really making a distinction between the spacecraft themselves and their payloads. In the context of ongoing missions directed towards settlement, spacecraft are useful materials that can be reused - even leftover fuel. So if it lands, it counts.