Like every astronaut's wife in the run-up to an important space mission, Gabrielle Giffords has written a "send off" note to her husband, Mark Kelly. Short and affectionate, it will be tucked into an inside pocket of his orange jumpsuit when the space shuttle Endeavour lifts off from Cape Canaveral in Florida on Friday.
Mr Kelly has flown three previous missions during his 15-year Nasa career, logging a total of 38 days in orbit. Each one of the previous spousal letters that helped him on his way began with the homey salutation: "sweetie pie". The latest, written by hand roughly a fortnight ago, is also said to follow in that happy tradition.
But in many other respects, it is a very different letter than its predecessors. The script has changed, because Ms Giffords now writes with her left hand. Sentences are shorter and the prose simpler.
It has been three-and-a-half months since the Congresswoman was shot in the head during a Saturday morning "meet and greet" outside a supermarket in Tucson. Since then, she has been largely confined to a ward at a hospital in Houston, where close friends, family and an élite team of doctors and neurosurgeons are monitoring her recovery.
Tomorrow's shuttle launch will provide a high-profile landmark in Ms Giffords's battle to return to full health. Her medical team has given her permission to travel to Florida for the big event. In her first public outing since the tragedy, she is expected to join a crowd of 40,000, including President Barack Obama, bidding farewell to Endeavour and its crew of six.
"It's something she's been looking forward to for a long time," Mr Kelly told reporters yesterday. "She's been working really hard to make sure that her doctors would permit her to come. She's more than medically ready to be here, and she's excited about making this trip."
Pia Carusone, the Congresswoman's Chief of Staff, added yesterday that her boss had boarded a private jet in Houston. "We haven't taken off, but we're at the airfield," she said. Ms Giffords apparently smiled to her fellow passengers and described her general mood as "awesome" prior to the flight. Yet even without the completion of this remarkable tale of human endurance, there would scarcely have been a dry eye in the house at Cape Canaveral tomorrow night. Endeavour mission STS-134 will not just open a new chapter in her story, it will mark the end of a historic era in space travel.
After almost a billion miles and three decades of boldly going, the space shuttle programme is being retired, with the loss of roughly 7,000 jobs. Endeavour's final 12-day trip, which will see it deliver a particle physics experiment to the International Space Station, will end with the spacecraft being transported to the California Science Centre in Los Angeles to become a museum piece.
The space shuttle programme – conceived under Richard Nixon and realised by Ronald Reagan before outlasting the Cold War – will have its swan song on 28 June, when Atlantis, the last remaining shuttle in Nasa's fleet (Discovery was retired two months ago), will go into orbit for the last time.
In addition to the 40,000 official guests at Cape Canaveral tomorrow, hundreds of thousands of onlookers are expected to jam the beaches and roadsides of Florida. Rob Varley, executive director of the Space Coast Office of Tourism, predicted 700,000 visitors. "There was nearly a half-million people here for the last launch," he said. "So I have no doubt, especially considering the fact that the Congresswoman is going to be here, and Obama is coming in. That just raises the level of awareness of the event."
The weather forecast is good, with only a 20 per cent chance of winds which would force the launch's delay. But other storm clouds litter Nasa's horizon. The agency is experiencing swingeing budget cuts and will soon be left in the embarrassing position of having its astronauts cadge lifts into space from Russia.
Though the US public has great affection for its shuttle fleet, it is even keener on slashing taxes and reducing spending. Space shuttles, which cost $2bn (£1.2bn) to make, and hundreds of millions more each year to maintain (even before they actually take off) are widely considered to be a luxury.
Then there are concerns about safety, which first surfaced with the Challenger disaster of 1986 and became seriously pressing after 1 February 2003, when Columbia disintegrated during re-entry to the Earth's atmosphere. On both occasions, the ships' entire crews perished. Future plans for US space exploration will see risks transferred to the private sector.
Mr Kelly, who spent his 20s watching footage of Endeavour (the shuttle was built in 1987) has always considered being asked to serve as its final captain as one of the signal achievements of his career.
But until very recently, it looked as if his plans would have to be abandoned. In the aftermath of the Tucson shooting – in which local teenager Jared Lee Loughner has been charged and now awaits trial – Mr Kelly told colleagues that he expected to be at his wife's bedside throughout the summer. Her rate of recovery surpassed expectations. After intensive work with physiotherapists and with speech therapists, Ms Giffords is now able to speak in short sentences, move the left side of her body and walk a few steps at a time.
She can also read, and is reported to have learned about the six people who perished and 15 who were wounded on the day she was shot by glancing at a newspaper that was left near her bed.
"So many people, so many people," she said.
8 January Democratic Congresswoman Gabrielle Giffords is shot in the head at a political event in Tucson, Arizona.
9 January Ms Giffords' husband, astronaut Mark Kelly, is granted leave of absence from the Endeavour space programme to be by her side.
12 January At a memorial service for six victims killed in the same Tucson shooting, President Obama declares that Ms Giffords has opened her eyes.
13 January Nasa announces a back-up shuttle commander to fill in for Kelly if he is unable to leave Ms Giffords by the Endeavour launch date, 29 April.
26 January Ms Giffords is moved to a rehabilitation facility as her condition is upgraded from "serious" to "good".
4 February Kelly announces that he will command the space shuttle Endeavour's final mission.
23 April Kelly enters quarantine to avoid illness. He is not allowed to see his family until just before the launch.
24 April Ms Giffords is declared well enough to travel to Cape Canaveral for the launch of space shuttle Endeavour.