Table of data
speed fraction of c time earth frame yr time on ship yr. length m mass kg fuel kg or L gamma 0.001 10,000 10,000 10 m 1,000 0.001 1.0000005 0.1 100 99.5 9.95 1,005 10 1.005 0.5 20 17.4 8.7 1,150 300 1.15 0.866 11.5 5.75 5 2,000 2000 2.00 0.707 14.1 10 7.09 1,410 820 1.41 0.99 10.1 1.42 1.4 7,100 12,200 7.1 0.999 10.01 0.455 0.45 22,000 42,000 22 0.9999 10.001 0.14 0.14 71,000 140,000 71 0.99999 10.0001 0.045 0.045 220,000 438,000 220 0.999999 10.00001 0.014 0.014 707,000 1,400,000 707
gamma = 1/(1-v^2/c^2)^0.5
Time earth frame Te= distance/speed = 10 lightyears/v
Time on ship Ts = Te/gamma
length = L/gamma
mass = mass x gamma
fuel energy = mc^2 (gamma-1) = measured in necessary anti-water (plus water) times 2 to start and stop
= 2 x (gamma-1)
for a speed of 0.866c this amount of energy costs $2 * 10^13 or 20 trillion dollars.