If you've ever dreamed of leaving terra firma and experiencing a life among the stars, astronaut Scott Kelly's new memoir will likely bring your expectations back down to Earth.

The 53-year-old, who collectively spent 520 days in space, including a record-breaking 340-day stint aboard the International Space Station, offers a blunt and humorous account of his time as a NASA astronaut in his new book "Endurance: A Year in Space, A Lifetime of Discovery." From the onset, Kelly's aim was to present an accurate picture of astronaut life unfiltered through the rose-colored glasses of public relations.

"[So many other NASA astronauts' memoirs] focus on the good stuff and not necessarily the personal things that happened in their lives, things they might not be proud of, things that we all have that makes us normal, relatable people," he told The Associated Press. "So I felt like sharing is good, but ... the bad stuff, too, makes the story more believable."

Scott Kelly's new book offers a blunt and personal account of the hardships and realities of living in space. Kelly's new book offers a blunt and personal account of the hardships and realities. (Photo: Penguin Books)

Kelly's story covers everything from the inspiration behind his desire to pursue a career in space (kickstarted by a college assignment to read the 1979 book "The Right Stuff" by Tom Wolfe, about the first Americans in space), to his 11-month mission in 2015 aboard the ISS. With the latter, he shares many details about the difficulties of surviving aboard a space station. Examples include descriptions of the cramped crew quarters, air that smells consistently "slightly burned, slightly metallic," and the congestion, headaches and burning eyes he regularly suffered from high carbon dioxide levels.

“It seemed like I lived there forever,” Kelly said during a press conference last year. “Maybe occasionally you do go bananas."

In addition to a lack of fresh food and no ability to shower (wet towels with disinfectant are the current preferred method), Kelly also came to yearn for much of what we all take for granted on a regular basis.

"Toward the end, I noticed little things were bothering me," he told Wired. "Like sitting at a table and having to keep track of my spoon. But mostly what you miss is people. Friends and family. And weather. Even just the wind, rain, sun, going outside."

Once Kelly completed his mission and returned to Earth, he faced the difficult task of becoming reacquainted with gravity. As he told CBS Morning in the video below, the swelling in his legs was particularly troublesome.

As NASA discovered, there were some unexpected internal changes as well. Part of the reason Kelly was selected to complete a year-long mission in space was so that scientists could study the biological differences between him and his identical twin, Mark Kelly, back on Earth. They found that not only did temporary shifts occur in Scott's DNA, but the ratio of two dominant gut bacteria species also diverged from normal.

"In the absence of gravity, especially after a year, our bodies do reconfigure and expand," Kelly told Publisher's Weekly. "I want to be clear about something: I did not grow two inches after my year in space, as reported all over the internet. That did not happen."

Despite the hardships of his various missions into space, Scott has no regrets about pushing himself mentally and physically to help advance the limits of human exploration. In fact, he's hopeful that his honest account of the realities of astronaut life might inspire others to do the same.

“When I read Tom Wolfe’s 'The Right Stuff' as a college student it changed the course of my life," he said, "and I hope that the same will happen after some young person reads 'Endurance.'"

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Scott Kelly's new memoir takes the romance out of living in space
In his book, "Endurance," astronaut Scott Kelly lays bare the highs and lows of living through NASA's longest single spaceflight.