John Grunsfeld, former astronaut and current associate administrator for NASA’s science mission directorate, will discuss the science behind The

He’s logged more than 58 days in space, but John Grunsfeld, associate administrator for NASA’s science mission directorate, will be exploring uncharted territory when he ventures to Liberty Hall, 644 Massachusetts St., this week.

“Two Astronauts, One Stellar Night” on Thursday marks the former NASA astronaut’s first visit to Kansas. The Lawrence Public Library-organized event, slated for 7:30 p.m., will see Grunsfeld and fellow former astronaut and KU professor Steven Hawley discuss the science behind this year’s Read Across Lawrence pick for adults, Andy Weir’s “The Martian.”

Veteran ABC News reporter and Sally Ride biographer Lynn Sherr will moderate the talk between the colleagues, who first met over 25 years ago at NASA.

John Grunsfeld, former astronaut and current associate administrator for NASA’s science mission directorate, will discuss the science behind The

“I was on the board that selected him,” Hawley says of Grunsfeld’s first space mission in 1995. “Actually, I think I was on the board that turned him down the first time, and I think that was in 1990.”

Does Grunsfeld know that?

“Well, he could know about it,” Hawley admits good-naturedly. “I don’t know if he thinks about it.”

In separate interviews with the Journal-World, the former space explorers discussed the scientific accuracy of “The Martian,” which, for those unfamiliar with the 2011 novel or last year’s film adaptation starring Matt Damon, follows a NASA astronaut stranded on Mars in 2035 after mistakenly being left for dead.

Turns out, Grunsfeld and Hawley are both willing to overlook a few astronomic (in both definitions of the word) hiccups for the sake of story development.

photo by: Richard Gwin

Kansas University Professor Steven Hawley, a former astronaut, holds a model of the Hubble Space Telescope in this Journal-World file photo from January 2014.

As others have pointed out, one of the novel’s (and film’s) biggest plot points is also its least plausible. Of the massive dust storm that separates astronaut Mark Watney from his evacuating crewmates, Grunsfeld says, “I’m OK giving that one a pass,” if only on the grounds of advancing the plot.

Hawley agrees. “Actually, there are sand storms on Mars, but the Martian atmosphere is so thin that storms don’t have much momentum,” he explains. “It would be very unlikely that you’d get blown over or knocked down a hill.”

For the record, the density of Mars’ atmosphere is just one percent of the Earth’s.

Grunsfeld is a bit pickier — “That’s just the way I am,” he says of his list of inaccuracies, which he acknowledges haven’t stopped him from enjoying “The Martian.” In addition to the sandstorm, Grunsfeld also points out a section in the book where Watney’s space suit, after being impaled by an antenna, starts filling up with pure nitrogen to “make up” for the lost gas leaking through the hole. In reality, NASA uses oxygen, not nitrogen, in its suits.

“Unfortunately, nitrogen is an inert gas, and the human body doesn’t know how to deal with pure nitrogen,” Grunsfeld says. “He would just stay unconscious until, basically, he died. That would be the end of the book on about page four.”

A few other life-threatening inaccuracies: the use of tempered glass in Watney’s space-suit visor (“you want bulletproof polycarbonate plastic,” Grunsfeld says; tempered glass shatters too easily to be worn in space) and hydrazine, which Watney uses to create water for his potato plants inside his crew’s Martian habitat. The stuff is one of the most toxic substances on Earth. NASA crews don what are essentially space suits while handling hydrazine down on Earth, Grunsfeld points out.

Keeping in mind that the action in the novel unfolds roughly 20 years from now, Hawley and Grunsfeld are both optimistic about our chances of sending humans to Mars by 2035, give or take a few years.

It’s certainly technologically possible. But NASA will need political and public support to make it happen, Hawley says. In 2035, perhaps a story like “The Martian” won’t be so far-fetched — minus pesky details like atmospheric density.

If you go:

– What: “Two Astronauts, One Stellar Night”
– Where: Liberty Hall, 644 Massachusetts St.
– When: 7:30 to 9 p.m. Thursday
– Cost: The event is free, but requires tickets. Only a few remained as of press time, though the library will make empty seats available to non-ticket holders starting at 7:15 p.m. For more information, call the Lawrence Public Library at 843-3833 or stop by in person at 707 Vermont St.