From 1990 to 1993, Walker took a leave of absence from Johnson Space Center to attend graduate school, where her area of study was the solar wind interaction with the Venusian atmosphere.

She returned to Houston in 2000 and became the technical lead for the ISS MER and the Deputy Manager of the On-Orbit Engineering Office.

[2] On September 19, 2011, NASA announced that Walker would command the NEEMO 15 undersea exploration mission aboard the Aquarius underwater laboratory from October 17–30, 2011.

[6] On June 15, 2010, Walker launched onboard Soyuz TMA-19, alongside fellow NASA astronaut Douglas Wheelock and Roscosmos cosmonaut Fyodor Yurchikhin.

Two days later the trio rendezvoused with the ISS and docked to the Zvezda module, officially becoming part Expedition 24 crew.

On November 26, 2010, Walker, Wheelock and Yurchikin departed the ISS onboard Soyuz TMA-19 and began their return home.

The crew, including Walker as mission specialist, docked to the ISS and join the Expedition 64 crew in November, alongside Russian cosmonauts, commander Sergey Ryzhikov and Sergey Kud-Sverchkov, as well as NASA astronaut Kathleen Rubins.

[2] Walker's recreational interests include cooking, soccer, running, weight training, flying, camping, and travel.

[2] This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.