Daniel Tani (born February 1, 1961) is an American engineer and a NASA astronaut. Although born in Ridley Park, Pennsylvania, he considers Lombard, Illinois, to be his hometown. With Peggy Whitson, Tani conducted the 100th spacewalk on the International Space Station.
Tani graduated from Glenbard East High School, Lombard, Illinois, in 1979, and received a Bachelor of Science and Master of Science degrees in mechanical engineering from Massachusetts Institute of Technology (MIT) in 1984, and 1988, respectively.
After Tani received his bachelor's degree from MIT, he worked at Hughes Aircraft Corporation in El Segundo, California as a design engineer in the Space and Communications group. In 1986, he returned to MIT and received his master's degree in mechanical engineering in 1988, specializing in human factors and group decision making. After graduation, Tani worked for Bolt, Beranek and Newman in Cambridge, Massachusetts, in the experimental psychology department. In 1988, Tani joined Orbital Sciences Corporation (OSC) in Dulles, Virginia, initially as a senior structures engineer, and then as the mission operations manager for the Transfer Orbit Stage (TOS). In that role, he served as the TOS flight operations lead, working with NASA/JSC mission control in support of the deployment of the ACTS/TOS payload during the STS-51 mission in September 1993. Tani then moved to the Pegasus program at OSC as the launch operations manager. In that capacity, he served as lead for the development of procedures and constraints for the launching of the air-launched Pegasus unmanned rocket. Tani also was responsible for defining, training, and leading the team of engineers who worked in the launch and control room.