Video game character becomes real 'Kerbalnaut' on Boeing Starliner

Jeb, an alien from the video game Kerbal Space Program, is seen in plush form on board Boeing's CST-100 Starliner spacecraft as the "zero-g indicator" for the Orbital Flight Test-2 (OFT-2) mission to the International Space Station.
Jeb, an alien from the video game Kerbal Space Program, is seen in plush form on board Boeing's CST-100 Starliner spacecraft as the "zero-g indicator" for the Orbital Flight Test-2 (OFT-2) mission to the International Space Station. (Image credit: Boeing via

In the spaceflight simulation game Kerbal Space Program, if the rocket you design does not reach its desired orbit or destination, you return to the (virtual) hangar to try to correct your problems and then launch again.

It seems only appropriate then that the first real-life flight of a Kerbal — the green humanoid aliens that populate the video game — should be on Boeing's second attempt and first success at docking its CST-100 Starliner crew spacecraft to the International Space Station.

Jebediah Kerman, or "Jeb" as he is better known to Kerbal Space Program fans, is one of four original "Kerbonauts" in the game and now the first to actually be launched into space — in the form of a plush toy. Jeb officially flew as the "zero-g indicator" for Boeing's Starliner Orbital Flight Test-2 (OFT-2), which arrived at the space station on Friday (May 20), the day after launching on a United Launch Alliance (ULA) Atlas V rocket from Cape Canaveral and two and half years after the first Starliner test flight was cut short by software issues.

Live updates: Boeing Starliner Orbital Flight Test 2 mission to ISS
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Boeing's Starliner Orbital Flight Test-2 zero-g indicator, a plush Jeb from the game Kerbal Space Program, is seen through a window into the space capsule. Jeb is seated next to "Rosie the Rocketeer," an anthropometric test device. (Image credit: Boeing via

In between flights, Boeing engineers performed a thorough review and conducted full-up tests, similar to what Kerbal Space Program players do between attempts in a simplified way. In both cases, the end result is mission success.

Jeb's presence aboard the Starliner was kept a secret until the uncrewed capsule successfully docked to space station. He was left for the station's Expedition 67 crew to discover floating on the end of a tether when they opened the hatch to the commercial spacecraft.

The Kerbonaut was chosen for the OFT-2 mission to represent the enthusiasm many on the Starliner engineering team have for the game, as well as the science, technology, engineering and mathematics (STEM) lessons it imparts to players, a Boeing spokesperson told

The 9-inch-tall (23 cm) Kerbal Jeb plush doll was provided by Private Division, the game's publisher. Identical Jeb dolls are available through the company's website.

"If you're playing Kerbal Space Program, or doing anything really, you need the perfect co-pilot," the company wrote. "Take Jeb with you on all of your expeditions in his 9-inch plushy form! He's still just as courageous."

From video game Kerbalnaut to real-life zero-indicator, Kerbal Space Program's Jeb is seen on Boeing's CST-100 Starliner. (Image credit: Boeing via

Zero-g indicators — referred to as such because they begin to float when their ride enters the microgravity environment of space — are a custom that was first started by Soviet-era cosmonauts. As NASA astronauts began flying with their Russian counterparts, they embraced the tradition and now zero-g indicators have become a part of U.S. commercial spaceflights.

Boeing's first Starliner flight test, OFT-1 in 2019, launched with a spacesuit-clad Snoopy doll as its zero-g indicator. Although the mission returned to Earth before it could reach the space station, Boeing released video of the Charles Schulz comic strip beagle floating above his seat on board the capsule.

Jeb will spend several days at the station before the crew closes the hatch to the Starliner and sends him on his way home. Pending acceptable weather conditions, the Starliner will undock and return to Earth for a parachute and airbag-cushioned touchdown at the White Sands Missile Range in New Mexico.

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Robert Z. Pearlman Editor, Contributor

Robert Pearlman is a space historian, journalist and the founder and editor of, an online publication and community devoted to space history with a particular focus on how and where space exploration intersects with pop culture. Pearlman is also a contributing writer for and co-author of "Space Stations: The Art, Science, and Reality of Working in Space” published by Smithsonian Books in 2018. He previously developed online content for the National Space Society and Apollo 11 moonwalker Buzz Aldrin, helped establish the space tourism company Space Adventures and currently serves on the History Committee of the American Astronautical Society, the advisory committee for The Mars Generation and leadership board of For All Moonkind. In 2009, he was inducted into the U.S. Space Camp Hall of Fame in Huntsville, Alabama. In 2021, he was honored by the American Astronautical Society with the Ordway Award for Sustained Excellence in Spaceflight History.