WASHINGTON — U.S. President Barack Obama has withdrawn the nomination of Lt. Gen. Susan Helms, a former astronaut, to become the next vice commander of Air Force Space Command at Peterson Air Force Base, Colo. Helms’ nomination, which had been held up since May by U.S. Sen. Claire McCaskill (D-Mo.) over questions about Helms’ decision to overturn a jury conviction in a sexual assault case, was withdrawn Nov. 7, according to a Library of Congress website that tracks presidential nominations.

Had she been confirmed, Helms would have become the Air Force’s second-highest-ranking uniformed officer for space. She is currently the commander of the 14th Air Force and commander of Joint Functional Component Command for Space at Vandenberg Air Force Base, Calif.

McCaskill, a member of the Senate Armed Services Committee, has pushed for legislation that reins in the authority of commanders to dismiss jury convictions against sex offenders as well as to require written justification for sentences that are lessened or commuted. 

Helms is a former space shuttle astronaut who has spent more than 200 days in space and was inducted into the U.S. Astronaut Hall of Fame in 2011. 

She was nominated for the vice commander position March 20.

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...