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These two bits of paper with notes hastily scrawled across them are actually part of the emergency checklist that helped save the crew of the doomed Apollo 13 space mission.
Astronauts marked the cards with critically important instructions after an explosion crippled their craft, prompting the famous 'Houston, we have a problem' line.
The record is a real time step-by-step account of how the crew set about powering down the craft in order to conserve enough power for them to get back to Earth.
The crew had to abandon the main command module and use the moon-landing Lunar module as a lifeboat to coast back to Earth.
Nasa experts had to very quickly recalculate the emergency procedures which they later radioed through to the crew.
Haise and Lovell marked the checklist accordingly in black and red pen while in space.
They opened and closed various circuit breakers in order to shut down and conserve battery power and marked on the list 'close' or 'open' on the appropriate circuit.
Haise made the first changes 79 hours into the mission and Lovell updated the list as he implemented further changes 82 hours in.
This flight plan from the first moon landing proves that Neil Armstrong intended to say the phrase 'One small step for A man, one giant leap for mankind'.
The extremely rare document is believed to be the only time the astronaut ever wrote the phrase and it is set to sell at auction for a phenomenal £55,000.
The iconic phrase - arguably the most memorable of the 20th Century - has been subject to years of debate to what was actually meant by Armstrong.
In an interview conducted with Mr McLeaish in 2001 he spoke of how he asked Armstrong what he said and Armstrong responded 'Well I know what I was meant to say'.
Armstrong then inscribed his intended phrase onto the flight plan.
Mr McLeaish kept the document in his office for years and it was one of his most prized possessions.
First man on the moon: Neil Armstrong was mission commander of Apollo 11
It was only sold on after the death of Mr McLeaish in 2007.
Armstrong said in his autobiography he has never written the phrase down, but experts believe he must have forgotten about writing it directly after his return to earth.