Maxell Hunter used in an explanation of times involved the figure of 100,000 feet/second takes 52 minutes or 3120 seconds of acceleration. The old minimal energy for transfer to another planetÃÂs orbit are in feet/second. One gauge the amount of travel left from the feet/sec via feet/second^2 * second.
What is the minimal required to get to the moon and back?
My mechanical background measurement was in thousandths of inches. Another old left over is the weight of metals measured in cubic inches. This was the unit of measure used in one of the books I had from the A.I.A.A American Institute of Aeronautics and Astronautics authored some time in the 1960s.