Time IS Relative

As my dear departed friend Kraft Ehricke so thoroughly and beautifully made the point-- the extra terrestrial imperative is the only honorable future for humanity. And once we are off this watery rock, the factor time is indeed very much relative. Wouldn't you agree dear reader?

Powering a Journey to Another Star

Posted on January 1, 2012 by andrewu

Based on Kepler‘s results, our galaxy contains one billion planets that can supportlife.  There’s only one problem: these planets orbit other stars, and even thenearest star is quite far away.  Science, through Einstein’s Special RelativityTheory, does provide at least one way to reach these planets within a traveler’s lifetime.  Unfortunately, the necessary technology has yet to be developed.

One of the big barriers to traveling to and colonizing planets around other stars is the energy required.  Special relativity provides a way to get there, but this way requires acceleration to near light speed.  This acceleration requires substantial energy inputs.  In fact, the energy required is so large that a starship likely won’t be able to carry the needed fuel onboard.  (Technically this is because the starship’s kinetic energy must exceed its rest mass energy for significant length contraction and time dilation effects to occur.)

One option for powering a trip to another star might be staged rockets using high-energy-density fuel such as antimatter for matter-antimatter annihilation.  There are two problems with this: we don’t know how to produce and store antimatter in such large quantities, and such a rocket would have to shed stages including some at very high speed.  Staging would also be very inefficient.

Another option is beamed power.  The simple version would be power beamed from the source or destination.  A more advanced version would add power beamed from waystations enroute.  For nearby interstellar destinations these waystations would be based on planetary or subplanetary bodies or perhaps even free-floating; for more distant destinations some of these waystations would be based around enroute stars.  These waystations would generate power by various means according to their location — nuclear power might be one common option.

Establishing and maintaining beamed-power waystations poses interesting economics questions.  Will they be unmanned or manned?  Assuming manned to support long-term maintenance, how will their staffs be motivated to maintain the beamed-power service.  The client ships will be unable to stop and dock at these waystations; to do so would defeat the purpose of the waystations.  This means the waystation staffs will have to be paid by other means.  This likely means that the waystations will have to be physically self-supporting over periods of many years.  Manned waystations will have to be small colonies of their own.

In the “Leave a Reply” section below, please share your thoughts on beamed-power waystations for interstellar travel.  Should they be manned or unmanned?  How will the economics work?  What other issues are important?