Editing Interplanetary spaceflight (section)

===Fuzzy orbits===
Computers did not exist when [[Hohmann transfer orbit]]s were first proposed (1925) and were slow, expensive and unreliable when [[Gravity assist|gravitational slingshots]] were developed (1959). Recent advances in [[computing]] have made it possible to exploit many more features of the gravity fields of astronomical bodies and thus calculate even [[Low energy transfer|lower-cost trajectories]].<ref>{{cite web | url=https://www.discovermagazine.com/the-sciences/gravitys-rim | title=Gravity's Rim | publisher=discovermagazine.com | access-date=2023-04-12 | archive-date=2019-10-22 | archive-url=https://web.archive.org/web/20191022002414/http://discovermagazine.com/1994/sep/gravitysrim419 | url-status=live }}</ref><ref>{{cite book |last=Belbruno |first=E. |date=2004 |url=http://www.pupress.princeton.edu/titles/7687.html |title=Capture Dynamics and Chaotic Motions in Celestial Mechanics: With the Construction of Low Energy Transfers |publisher=Princeton University Press |isbn=9780691094809 |access-date=2007-04-07 |archive-url=https://web.archive.org/web/20141202074354/http://www.pupress.princeton.edu/titles/7687.html |archive-date=2014-12-02 |url-status=dead }}</ref> Paths have been calculated which link the [[Lagrange points]] of the various planets into the so-called [[Interplanetary Transport Network]]. Such "fuzzy orbits" use significantly less energy than Hohmann transfers but are much, much slower. They aren't practical for human crewed missions because they generally take years or decades, but may be useful for high-volume transport of low-value [[commodity|commodities]] if humanity develops a [[space-based economy]].