Megan McArthur will be on the International Space Station for six months while her husband and fellow astronaut Bob Behnken takes care of their son Theo

Megan McArthur is set to blast off from Kennedy Space Center in Florida atop a 21-story SpaceX Falcon 9 rocket next Thursday — an out-of-this-world milestone with which her family already has some experience.

As the pilot of the Crew Dragon capsule, she'll be ferrying herself and three other astronauts in a 24-hour journey to the International Space Station (ISS) for a six-month scientific mission. But while there are all sorts of risks associated with blasting off on top of giant Roman candle with 1.7 million pounds of thrust underneath you — not to mention having to forgo showers for six months on the ISS! — the tougher job might be for her husband and fellow astronaut Bob Behnken, who will be at home in Houston taking care of their 7-year-old son, Theo.

Listen below to the episode of our daily podcast PEOPLE Every Day for more on Megan McArthur and Bob Behnken.

There's also the helplessness of not being able to use your skills to help your partner in any way should something go wrong, as McArthur, 49, felt last summer when Behnken, 50, test piloted the same Crew Dragon capsule to the ISS for a two-month stay. 

"I think that the harder job is the job where you are the one at home that's not doing the operation," she tells PEOPLE in this week's issue. "It feels different when you take those risks for yourself than when the person you love has chosen to take them and you can't help them in any way. You're not working on these problems and these tasks together."

Behnken is going to be on home-front duty three times as long as McArthur, who will celebrate her 50th birthday in space this summer, just as Behnken did. 

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"I really know what that's going to be like for them [minus a spouse and parent]," she adds, "and I hope that that makes me more understanding when they don't want to talk to me on the phone when I'm ready to talk to them, or maybe the video chat doesn't go so well one weekend. Just understanding that they've got a lot going on, too."

The couple met in 2000 when they were both part of that year's astronaut candidates' class. They married in 2008, and McArthur made her first flight aboard the space shuttle the following year to service the Hubble Telescope. She has spent the last year preparing for this mission in Houston, Los Angeles (learning to pilot the Crew Dragon), Japan, Germany and Russia (all astronauts need to know how to safely live and work inside of the other countries' portions of the ISS).

Behnken, who has logged more than 2,000 hours in space and completed 10 spacewalks during his three missions, is ready for his Earthly mission, too, since he's been taking up a lot of the childcare and cooking duties so McArthur could intensify her training two weeks after he returned from the ISS last August. 

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"But with Megan being gone for six months, it'll be kind of a unique experience for me," he says. "We haven't been apart for that long of a period of time, and our son certainly will be having a different experience to have his mom off the planet."

ben behnken and megan mcarthur
Megan McArthur and Bob Behnken with son Theo
| Credit: Courtesy Megan McArthur and Bob Behnken

With a doctorate in mechanical engineering, Behnken can figure out just about anything, but make no mistake: McArthur is the cook in the family. Homemade desserts are her specialty. 

"Theo is really going to miss her cookies, so I'll have to figure out how I can keep him happy with a cookie to the performance level that Megan has set as his expectation," he says. "But what I'll miss mostly is having another set of hands around the house."

McArthur just has one request while she's orbiting the planet at 17,500 mph doing zero-gravity experiments for six months: "I've asked him not to rearrange the kitchen while I'm gone."