On Friday, September 16, 2016 at 6:58:18 PM UTC+12, William Mook wrote:
80.7 - average adult body mass
35.0 - biosuit with MEMS life support
36.0 - consumables (12 days)
151.7 - total payload

260.7 - propellant (1,140 mm diameter sphere)
40.1 - liquid hydrogen
220.6 - liquid oxygen

412.4 - payload projected to moon

708.6 - inert propellant (water) (767 mm diameter sphere)

1121.0 - total take off weight (Earth)

https://www.youtube.com/watch?v=XhUasBcoj-Q

2803 kgf (27,484 Newtons) force produced by energising 2 litres of water per second at the outset, with 190 megawatt laser beam - boosts hydrogen and oxygen to a speed of 14 km/sec. The unit boosts straight up at 2 gees and rises to 7.1 gees at first stage burnout - attaining 10.9 km/sec - a trans-lunar trajectory - before disappearing over the horizon!

The LOX/LH2 on board is used to slow the vehicle to land on the lunar surface and return to Earth - via direct ascent and return. The system is 1.53 meters in diameter and 4.00 meters in length - 3.5 days outbound - 3.5 days inbound - 4 days on lunar surface - 1 day reserve.

Now, if we put the 412.4 kg payload atop a three stage rocket that imparted ideally 4 km/sec per stage, and had a 4.5% structure fraction, using LOX/LH2 - you'd have;

Payload 412.4
u.......... 0.5971
p.......... 0.3579.... Propellant LH2.... LOX... Structure
Stage 3 1,152.31 688.05 105.85 582.20 51.85
Stage 2 3,219.72 1,922.53 295.77 1,626.76 144.89
Stage 1 8,996.40 5,371.84 826.44 4,545.40 404.84

Diam Total LH2 vol LOX vol
Stage 3 1.57 2.02 1.51 0.51
Stage 2 2.21 5.65 4.23 1.43
Stage 1 3.11 15.79 11.81 3.99

So, a 9 metric ton vehicle 24 meters tall projects the 412.4 kg lunar capsule on to a direct ascent lunar trajectory. Stage 3 is deflected for a lunar free return and recovery.

This replaces the 190 Megawatt laser beam. Which is more cost efficient? That depends on the details.

For comparison, a 70% efficient solar pumped thin disk terrestrial laser, produces at peak insolation 200 MW of optical energy from an array of concentrating collectors 540 meters on a side.

http://www.explore-atacama.com/eng/a...de-la-luna.htm
http://www.ipsnews.net/2013/10/chile...ergy-shortage/

Building this in the Atacama region of Chile, in the Valley of the Moon, is appropriate! It provides 11 hours of sunlight per day - and with three launches per hour possible, 33 ships could be dispatched every 24 hours. 84 hours out, 84 hours back and 84 hours on the moon, 347 ships in transit, and another 347 ships in the shop for reuse. A one way journey, with return of the empty vehicle, operating as a drone, is capable of placing 200 kg on the lunar surface without return. This permits the construction of shelters and outposts anywhere on the lunar surface. Similar payloads can be placed in lunar orbit to provide real time high resolution mapping of the lunar surface.