A notebook containing Apollo 13 commander James Lovell's handwritten calculations to guide the damaged spacecraft back to Earth is being auctioned along with other artifacts from the 1970 mission.
Heritage Auctions in Dallas Texas said the notes came hours after the famous "Houston, we have a problem" phrase from the commander.
Known as the Lunar Module Systems Activation Checklist, the notebook is expected to fetch $25,000 when the auction concludes November 30.
"There are few space artifacts as evocative or important as this little booklet," said Michael Riley, historian at Heritage Auctions.
"Without these successful calculations and the fast transfer of the information from one computer to the other, the Apollo 13 crew would not have known their position in space, possibly causing the outcome of the already ill-fated mission to be quite different."
Lovell "has held this checklist book in his personal collection for 41 years and now feels it's time to turn over its stewardship to another person," said Riley.
Apollo 13 grabbed the world's attention in April 1970 as it managed a safe return after an oxygen tank explosion that required the crew to rig a new carbon dioxide removal system. The flight was the subject of a blockbuster film of the same title.
Other items auctioned include John Young's Apollo training-used coverall jacket and a handwritten Apollo 11 log from author and scientist Charles Pellegrino.
Lovell's binder of 70 pages has several ink notations in various areas and some pencil calculations on two internal pages.
Explore further: Image: View of mission operations control room during the Apollo 13 mission