Endeavour Commander Mark KellyGoogle Images

Read more: Congresswoman Giffords and Obama will attend launch of space shuttle Endeavour

Read more: Astronaut Mark Kelly, spouse of Gabby Giffords, an American hero --- intensely proud of his Irish heritage

This Friday afternoon will see the final launch of the Endeavour shuttle at Cape Canaveral. This will be Irish American Commander Mark Kelly's fourth flight into space and most likely his last.

The shuttle launch will be witnessed by his wife, who is still recuperating from a serious gun wound to the head, Congresswoman Gabrielle Giffords, along with Kelly's two teenage daughters, his parents, his twin brother Scott and President Barack Obama.

On Tuesday 47-year-old Kelly flew to Florida, along with his team, to prepare for the 14-to-16 day flight to the International Space Station.

On January 8, his wife Giffords was shot in the left side of the brain outside a supermarket in Tucson. Thirteen people were wounded and six were murdered including a nine-year-old girl and a federal judge. Initially Kelly rushed to his wife's beside and there were question over whether he would still run as commander on this flight. However as Giffords condition improved Kelly went back to work in February.

Both Mark, and his identical brother Scott, honed their skills as high performance Navy pilots - focus and putting their personal lives aside comes naturally to them both.

Speaking at a press conference last month Kelly said "I've given this mission everything I would have if the events of January did not happen…I'm very focused."

Fellow astronaut Andrew Fuestel said "We want Mark on the mission. We always have…He's been our commander for a year and a half, and that's the way the mission needs to fly."

Feustel insists that although Giffords shooting was tragic it "doesn't influence us on the mission at all…It's really not had any significance on the technical aspects of the mission."

Kelly grew up in West Orange, New Jersey the son of police officers. Kelly, who has been an astronaut has always loved speed and risk but started out on the slow ships in the US Merchant Marine Academy in the mid-1980s. He worked as a grain carrier in the Pacific.

He recalled "I thought, 'Boy, this is way too slow…That's when I started thinking about flying airplanes in the Navy."

In 1993 both brothers ended up in the Naval Test Pilot School. Soon even the Navy's fighter planes weren't fast enough for the twins. In 1996 they were both selected as astronauts by NASA. They are the world's first and only space siblings.

The brothers had thought that they would get the chance to travel into space together but this has now been nixed as Mark will launching for the final time today. When asked who else he would like to travel to space with he said "If it wasn't so dangerous, maybe my kids and my wife and my brother all at once…But this flying in space stuff is a risky proposition. So I wouldn't let my kids do it, not at their current age."

Kelly, of Irish Catholic descent, took a months leave from training to campout at his wife's bedside then she was shot. He has said that he believes that the power of pray helped in Giffords' recovery.
Speaking at the National Prayer Breakfast a month after Giffords' shooting he said "I hadn't been a big believer in faith until recently…I thought the world just spins and the clock just ticks and things happen for no particular reason."

After the shooting the lawn outside his wife's hospital was littered with angels, Bibles and prayers. He said he realized then that is was as sacred a spot as any church, temple or mosque. Kelly said "A place with heaven itself as a ceiling." He added that from space "you have an entirely different perspective of life on our planet…It's humbling to see the Earth as God created it in the context of God's vast universe."

Read more: Congresswoman Giffords and Obama will attend launch of space shuttle Endeavour

Read more: Astronaut Mark Kelly, spouse of Gabby Giffords, an American hero --- intensely proud of his Irish heritage