Washington, Jan 14 (Agencies): Astronaut Mark Kelly, whose politician wife is recuperating from injury received during a murder attempt, still expresses hope to lead the Endeavour shuttle's mission to space on April 19, NASA said on Thursday.

However the US space agency announced a backup commander just in case, and said he would begin training with the rest of the astronauts next week.

Kelly's status has been in doubt since his wife, Arizona Congresswoman Gabrielle Giffords, was shot point-blank in the head by a gunman, who killed six others at a grocery store political meeting on Saturday.

"I recommended to my management that we take steps now to prepare to complete the mission in my absence, if necessary," Kelly said in a statement issued by NASA.

"I am very hopeful that I will be in a position to rejoin my STS-134 crew members to finish our training."

Astronaut Rick Sturckow will serve as a backup commander and will begin training next week with the rest of the crew, NASA said.

"Mark is still the commander of STS-134," said Peggy Whitson, chief of the Astronaut Office.

"He is facing many uncertainties now as he supports Gabrielle, and our goal is to allow him to keep his undistracted attention on his family while allowing preparations for the mission to progress," she said.