Published: Feb 04, 2011 3:44 AM EST
Updated: Feb 04, 2011 12:44 AM EST

CAPE CANAVERAL, Fla. (AP) - The astronaut husband of wounded Rep. Gabrielle Giffords will announce Friday whether he'll fly on space shuttle Endeavour's final voyage - and all signs are go.

Mark Kelly will take part in a press conference Friday afternoon at Johnson Space Center in Houston, NASA announced late Thursday. The astronaut who has been substituting for Kelly during training, however, is not among the three participants, suggesting that Kelly has decided to fly in April.

His identical twin, Scott, hinted in an interview this week that his brother would choose to fly.

Mark Kelly took a leave from training after Giffords was gunned down at a Tucson, Ariz., shopping center on Jan. 8. She's been undergoing rehab in Houston for the past two weeks.

Kelly spent the past month debating whether to step down as commander of Endeavour's two-week mission. In the meantime, NASA named a backup commander, Rick Sturckow, who joined crew training.

Kelly, 46, has flown three times aboard space shuttles; April's mission - targeted for April 19 - would be his fourth. His astronaut brother, Scott, is currently the commander of the International Space Station.

The fact that Sturckow is not listed for the press conference is telling, indicating that Kelly will launch as scheduled, said Howard McCurdy, a public policy professor and space expert at American University in Washington, D.C.

And because it will be one of the last two launches and because of the drama behind the shooting of his wife, that shuttle launch will "get the same kind of attention that the (1998) John Glenn mission" received, McCurdy said. NASA is retiring the shuttle fleet this year; three missions remain.

McCurdy suggested the public will embrace Kelly's decision, because it provides a sense of normalcy.

"We all want her to go back to Congress; we'd like them both to continue their careers and we'd like them to be whole and normal as if this thing had never happened," said McCurdy, author of the book "Space and the American Imagination."

Both Kellys are Navy captains and joined NASA's astronaut corps in 1996. In an interview from the space station Wednesday, Scott Kelly said their Navy background as high-performance pilots enables them to put their personal lives aside, when necessary, and focus on the job at hand.

"My brother certainly is very good at that," he told The Associated Press. "If he does choose, and NASA management chooses, for him to fly this mission ... I am absolutely 100 percent confident that he will have no problem fulfilling his responsibilities the same way as if this incident would have never occurred."

(Copyright 2011 by The Associated Press.  All Rights Reserved.)