As an undergraduate student at Cal Poly, Chamitoff taught lab courses in circuit design and worked summer internships at Four Phase Systems, Atari Computers, Northern Telecom, and IBM. He developed a self-guided robot for his undergraduate thesis project. While at MIT and Draper Labs (1985–1992), Chamitoff worked on several NASA projects. He performed stability analyses for the deployment of the Hubble Space Telescope, designed flight control upgrades for the Space Shuttle autopilot, and worked on the attitude control system for Space Station Freedom. His doctoral thesis developed a new approach for robust intelligent flight control of hypersonic vehicles.
From 1993 to 1995, Chamitoff was a visiting professor at the University of Sydney, Australia, where he led a research group in the development of autonomous flight vehicles, and taught courses in flight dynamics and control. He has published numerous papers on aircraft and spacecraft guidance and control, trajectory optimization, and Mars mission design.
In 1995, Chamitoff joined the Motion Control Systems Group in the Mission Operations Directorate at the Johnson Space Center, where he developed software applications for spacecraft attitude control monitoring, prediction, analysis, and maneuver optimization.
Selected by NASA for the Astronaut Class of 1998, Chamitoff started training in August 1998 and qualified for flight assignment as a Mission Specialist in 2000. He worked in the Space Station Robotics branch, was lead CAPCOM for ISS Expedition 9, acted as Crew Support Astronaut for ISS Expedition 6, and helped develop onboard procedures and displays for Space Station system operations.
Tennis balls that Chamitoff and Garriott juggled while aboard the ISS
Chamitoff served on a long duration mission to the International Space Station. He launched as a Mission Specialist on board Space Shuttle mission STS-124. He was Flight Engineer 2 and Science Officer on Expedition 17. He returned home as a Mission Specialist on STS-126, completing a tour that lasted six months.
As part of his personal allowance, Chamitoff brought the first bagels into space, 3 bags (18 sesame seed bagels) of Fairmount Bagels with him, from his cousin's bagel bakery. He also bought a velcro chess set and started playing games against mission control, which got quite competitive. Chamitoff also placed a Mezuzah shaped like a rocket made by British-Israeli silversmith Laura Cowan "on the door post near his bunk bed" on the International Space Station. 
After conducting experiments with the SPHERES during his mission, he founded the Zero Robotics competition, where high school students program the robots.
Chamitoff served as a mission specialist on STS-134, the penultimate Space Shuttle mission, during which he made two spacewalks, the last of which completed the construction of the ISS.
Gregory Chamitoff on the International Space Station (ISS), early November 2008.
Expedition 17 crew portrait B
Chamitoff during the final spacewalk of the STS-134 mission.
STS-134 Mark Kelly, Roberto Vittori and Greg Chamitoff during a break in the Unity node
Post NASA Career
Chamitoff is currently the Lawrence Hargrave Professor of Aeronautical Engineering at the University of Sydney, Australia and a Professor of Engineering Practice in the Aerospace Engineering Department at Texas A&M University in College Station, Texas. He instructs senior design, human spaceflight operations, and dynamics and controls for aerospace vehicles.