Lunar Surface Preliminary EVA Assumptions

In laying out a strawman timeline for lunar surface operations on the first flight, we need something to start from. If we have a guess as to how many EVA sorties we'll do, how long the crew will be on the surface, and what they'll do, then we can start figuring out what resources are required to do all that.

Let's assume few basic requirements:

1. Max EVA sortie time = 6 hours
2. Crew sorties limited to 1/2 hour walk-back time unless they have emergency equipment (such as a pressurized rover) with them
3. 24-hour days, with 1 hour post-sleep and pre-sleep activity
4. 2 hours for EVA prep before each sortie
5. Airlock pump recovers 90% of the gas
6. Post-EVA checklist takes 3 hours. (It looks like we'll have to do some meticulous cleaning and maintenance.)

Let's base this on using a triple Spacehab module, 27 feet long, 12 feet wide, and ceiling at 8 to 9 feet.