— Former NASA astronaut Robert "Hoot" Gibson is selling pages from the checklists he used on his first space shuttle mission.

There are two things remarkable about that.

First, in the more than 40 years since he launched as the pilot of mission STS-41B, Gibson has never sold anything that he carried to or used in space, even on his later four flights as commander.

Secondly, he was never supposed to have his flown checklists.

"I have a number of checklists that I flew on my first two missions that NASA mistakenly let us keep," said Gibson in a 2018 interview with a NASA historian. "They weren't supposed to do that."

To be clear, it was not just Gibson. In the wake of the loss of the space shuttle Challenger in 1986 — the same winged spacecraft that Gibson flew on 41B — NASA's policies were put under a magnifying glass and scrutinized "from top to bottom."

"In the review it came out that NASA was just letting us keep checklists that weren't going to get used again. For example, my whole entire flight plan for [STS]-41B and for 61C, I have that. It actually flew," Gibson said. "After Challenger that came out [and] they went, 'Whoa, you're not supposed to have been doing that.'"

The intention had been, and from that point forward, all of the flown checklists were sent to the National Archives. But no one came back to Gibson or any of the crew members from the first 24 space shuttle flights to say "turn it all back in."

"So, I've still got all that," Gibson said.

Or rather, he had all of it. One hundred of the checklist pages are now selling for $325 to $950 each.

"We are offering an opportunity for space enthusiasts to own a piece of history," wrote Michelle Rouch, an artist who illustrated Gibson's first children's book, "First Flight," in an email sent to collectSPACE. "The pages were carefully hand selected by Hoot from three of his checklist books and reference data."

Rouch, together with Gibson's co-author, Czarina Salido, organized the sale, which is hosted on Rouch's website. A portion of the proceeds ($275) from each page is a tax-deductible donation to Taking Up Space/Time in Cosmology, a nonprofit founded by Salido that promotes and conducts STEM (science, technology, engineering and mathematics) education for Native American girls.

Each flown checklist page is accompanied by a copy of "First Flight" signed by Gibson, Rouch and Salido, as well as a "First Flight" bookmark and an original ink sketch by Rouch of the "First Flight" logo signed by her and Gibson. Also included is a certificate of authenticity that pictures the checklist page it accompanies and is signed by Gibson.

The 100 pages were selected from multiple checklist books, including the instructions related to deploying two satellites and the steps for operating all of the different types of still and TV cameras aboard the space shuttle.

STS-41B included the world's first spacewalk conducted without a tether. Bruce McCandless famously donned the MMU (manned maneuvering unit) — a jet backpack — for the first time and flew out into space, resulting in a series of iconic images of just him above Earth's horizon.

Gibson took those photos.

"The reason that I was there parked by the window with camera in hand was that on the spacewalk as the pilot, the copilot, I was the only person on the crew that had absolutely nothing to do," said Gibson, who acknowledged also having a life-long passion for photography.

Although none of the checklist pages for sale directly address photographing the spacewalk, there are references to the 70mm Hasselblad camera that Gibson used for those shots.

"Reading history in these instructions, I can just envision the moment Hoot was photographing McCandless," said Rouch.

Some of the pages have handwritten notes, such as what the shuttle's instruments were reading at a given time, or have sections highlighted by Gibson.

"And one page has a little cylindrical drawing," Rouch told collectSPACE. "This is the only page within the entire stack of 100 artifacts that shows an original Robert 'Hoot' Gibson drawing."

The sketch is of the IRT, or Integrated Rendezvous Target, which was a balloon designed to inflate to be 6 feet (1.8 meters) wide, but had a deployment issue.

"We were to operate the shuttle rendezvous radar and software with it as our target. It was to be a 100-pound (45-kg) lead balloon but after we launched it the balloon exploded," Gibson wrote in an email to Rouch.

Although the sale means the original checklists are being divided and sent out across the world, the information they contain is being kept together.

"These space shuttle flown artifacts from STS-41B have each been scanned and Hoot will have a copy," said Rouch. "This is his personal collection. I will ask if he wants to have these files also given to the National Archives or other depository."