This actually happened on Apollo 13. Backup pilot Jack Swigert was assigned to Apollo 13 two days before launch because the expected pilot, Mattingly, had been

This actually happened on Apollo 13. Backup pilot Jack Swigert was assigned to Apollo 13 two days before launch because the expected pilot, Mattingly, had been potentially exposed to rubella. The flight launched on April 11, just a few days before the April 15 tax deadline and Swigert realized in flight that he had forgotten to file his taxes. Flight controllers thought it was a joke but Swigert was serious: "It ain't too funny. Things kind of happened real fast down there and I do need an extension. I may be spending time in another quarantine besides the one that they're planning for me." (I.e. besides the 21-day astronaut quarantine, he might end up in prison.) The IRS stated that they could resolve the problem since anyone outside the United States on April 15 automatically gets a two-month extension. (Even though "legally, no one has ever decided whether a journey into space technically counts as leaving the United States.") Of course, Apollo 13 soon had problems that pushed aside any concerns of tax filing. NY Times report: https://www.nytimes.com/1970/04/13/archives/apollo-13-coasts-toward-the-moon-aim-is-corrected-rocket-fired-34.html https://www.nytimes.com/1970/04/13/archives/apollo-13-coasts... Mission transcript: https://www.nasa.gov/wp-content/uploads/static/history/alsj/a13/AS13_TEC.PDF https://www.nasa.gov/wp-content/uploads/static/history/alsj/...