Editing Interstellar travel (section)

=== Wait calculation ===
The [[speculative fiction]] writer and physicist [[Robert L. Forward]] has argued that an interstellar mission that cannot be completed within 50 years should not be started at all. Instead, assuming that a civilization is still on an increasing curve of propulsion system velocity and not yet having reached the limit, the resources should be invested in designing a better propulsion system. This is because a slow spacecraft would probably be passed by another mission sent later with more advanced propulsion (the incessant obsolescence postulate).<ref name="Bob Forward 1996" /> In 2006, Andrew Kennedy calculated ideal departure dates for a trip to Barnard's Star using a more precise concept of the wait calculation where for a given destination and growth rate in propulsion capacity there is a departure point that overtakes earlier launches and will not be overtaken by later ones and concluded "an interstellar journey of 6 light years can best be made in about 635 years from now if growth continues at about 1.4% per annum", or approximately 2641 AD.<ref>{{Cite journal |last=Kennedy |first=Andrew |date=July 2006 |title=Interstellar Travel: The Wait Calculation and the Incentive Trap of Progress |url=https://gwern.net/doc/statistics/decision/2006-kennedy.pdf |journal=Journal of the British Interplanetary Society |volume=59 |pages=239–246 |bibcode=2006JBIS...59..239K |access-date=9 June 2023 |number=7}}</ref> It may be the most significant calculation for competing cultures occupying the galaxy.<ref>Kennedy, A., "The Wait Calculation: The Broader Consequences
of the minimum time from now to interstellar destinations and its significance to the space economy". JBIS, 66:96-109, 2013</ref>