## FOOTNOTES

1_My thanks to Ron Sirull, who pointed this out to me on the CNN Lunar Science message board.

2_The calculation for track length is based on the equations for acceleration and distance from high school physics, which you may remember as the following:

v = at               (1)
x = (1/2)at2        (2)

Substituting  v/a for t in #2 you get this:

x = (1/2)a(v2/a2) =  (1/2)v2/a (3)

Since the track is used both for acceleration and deceleration, you need twice as much track, so the final equation is this:

x = v2/a

For 1g (9.82 m/sec2) and 8500 kph (2361 m/s) you get this:

x = (23612)/9.82 = 567649.7963m (567 km)

With this basic number (567 km), all you need do is divide it by the number of gs you intend to accelerate and decelerate the train with, so at 10gs the number becomes 56.7 km.

3_The Advanced Life Support and Gravitational Biology group at Kennedy Space Center runs a biomass production chamber, which has 113 m3 of chamber volume.  The chamber contains approximately 20m2 of planter area, and is illuminated with 96 400watt high pressure mercury vapor lamps, for a total lamp wattage of 38400 watts.  This biomass production chamber generates 50% the food requirement for one person, takes care of  80% of the O2/C02 recycling needed per person, and 260% of the water generation (through transpiration) for one person.  By using the smallest percentage value above, I roughly calculated you would need twice this chamber volume/planter area per person to supply the food needs on a moonbase.   This implies a 226 m3 chamber volume with 40 m2 planter area and lighting power requirement of 76800watts per person on the moonbase.  The data I used comes from http://bioscience.ksc.nasa.gov/oldals/plant/bpframe.htm and probably should only be considered a rough guide (Your milage may vary).

4_To continue from footnote #3, if a 40 m2 planter area is illuminated with more standard grow bulbs, very different figures for a biomass production facility arise.  For instance, incandescent commercial grow bulbs, covering an area of about 9 to 16 square feet (a 3x3 foot square or a 4x4 foot square) can be purchased in either 250 watt or 400 watt capacities.  To illuminate our 40 m2 planter area, about 40 bulbs (or a little less) would be needed, translating to a power requirement of somewhere between 10 kw and 16 kw per person, not 77 kw per person, on the moonbase.   This doesn't begin to consider other options, such as flourescent bulbs, or a mix of bulbs.

Also, with a large enough base with a big enough gas reserve, there is the possibility of letting the plants run at a lower capacity during the lunar night and at a higher capacity during the lunar day.  So you see, the term, "your milage may vary,"  readily applies here.