Fermi Problems Solving

Question

Estimate the mass of food and water that a team of six astronauts would need for a standard two-year mission to Mars. (Note: the two years includes the round trip.)

Answer 1

How much do you eat in a day? about 1-2 pounds or .5 to 1 kg

How much do you drink in a day? about 8 cups or 2 quarts or 2 liters or 2 kg say 1-2 kg

By what factor is an astronaut bigger than you? 1 to 1.5 (or could be down to .75) factor

days in two years 2 x 365 or about 750

Now it's just a matter of how you estimate (kg)

a) order of magnitude 1*1*1*1000 = O(1000)

b) 1 2, or pi ( or 1 or pi) system (pi² is about 10) .1*2pi*pi/2*2pi*100 = 2pi*100 = O(1000)

c) 1,2,or 5 system 1*1*500 = 500 = O(1000)