Astronauts, cosmonauts, and spaceflight participants have observed their religions while in space; sometimes publicly, sometimes privately. Religious adherence in outer space poses unique challenges and opportunities for practitioners. Space travelers have reported profound changes in the way they view their faith related to the overview effect, while some secular groups have criticized the use of government spacecraft for religious activities by astronauts.
On Christmas Eve, 1968 astronauts Bill Anders, Jim Lovell, and Frank Borman read from the Book of Genesis as Apollo 8 orbited the Moon. A lawsuit by American Atheists founder Madalyn Murray O'Hair alleged that the observance amounted to a government endorsement of religion in violation of the First Amendment, but the case was dismissed.
Apollo 11 astronaut Buzz Aldrin, a Presbyterian, performed a communion service for himself using a kit provided by his church. Aldrin had told flight director Chris Kraft of his plans and intended to broadcast the service back to Earth but opted not to at the request of Deke Slayton, due to the continuing controversy over Apollo 8's reading.
A microfilm Bible that had been to the surface of the Moon was auctioned off in 2011. It was a King James Version created after three astronauts lost their lives in the Apollo 1 fire. Ed White, one of the astronauts who perished, had wanted to take a Bible to the Moon.
A signed message from Pope Paul VI was included among statements from dozens of other world leaders left on the moon on a silicon disk during the Apollo 11 mission. Following the mission William Donald Borders, Bishop of the Roman Catholic Diocese of Orlando, told the Pope that the 1917 Code of Canon Law placed the moon within his diocese, as the first explorers had departed from Cape Kennedy which was under his jurisdiction.
Russian Orthodox Christmas was celebrated on the International Space Station, on January 7, 2011. Cosmonauts had the day off, but one of the other crew tweeted, "Merry Christmas to all Russia." The whole crew also celebrated on December 25, two weeks prior.
Muslims in space struggle with fulfilling their religious obligations including kneeling and facing Mecca to pray in microgravity traveling at several kilometres per second. The issue first came up when Sultan bin Salman bin Abdulaziz Al Saud, a Saudi prince, flew aboard STS-51-G and again when Anousheh Ansari flew as a tourist to the International space station. In preparation for Malaysia's Sheikh Muszaphar Shukor trip to the ISS in 2007, the National Fatwa Council created "Muslim Obligations in the International Space Station" outlining permissible modifications to rituals such as kneeling when praying (not required in space), facing Mecca when praying (left to the astronaut's best abilities at the start of prayer), and washing (a wet towel will suffice).
In February 2014, the General Authority of Islamic Affairs and Endowment (GAIAE)[clarification needed] issued a fatwa forbidding devout Muslims from participating as crew members in Mars One's proposed one way mission to Mars. Speaking for the clerical group, Farooq Hamada explained that, "Protecting life against all possible dangers and keeping it safe is an issue agreed upon by all religions and is clearly stipulated in verse 4/29 of the Holy Quran: Do not kill yourselves or one another. Indeed, Allah is to you ever Merciful."