With wounded U.S. Rep. Gabrielle Giffords on hand to watch, the space shuttle Endeavour is poised to give the work week a roaring and historic start Monday morning, overcoming wiring problems that grounded it last month.
Giffords' arrival Sunday afternoon included a quick fly-by of Endeavour on the launch pad, ready to go.
"Gabrielle is excited for tomorrow's launch. Do you plan to see history in the making?" her staff tweeted.
NASA officials said conditions, from weather to technical issues, couldn't look much better for the scheduled 8:56 a.m. (1256 GMT) launch Monday.
Giffords, traveling on a NASA jet with the family of pilot Gregory Johnson, arrived shortly after the protective structure that surrounds Endeavour was moved out of the way a milestone in launch preparations that allows fueling to begin late Sunday night.
NASA was so ready to get the flight off the ground that they moved the protective scaffolding 15 minutes earlier than planned.
There was only a 30 percent chance of a weather delay, mostly because of crosswinds.
The conditions were far different from last month's futile launch attempt. The protective cover wasn't removed for five hours because of storms, and the launch was scrubbed because of an electrical problem.
NASA is expecting slightly smaller crowds, 400,000 people instead of 750,000 people, for the second attempt. The media horde is also slightly thinned — even though the April attempt was on the same day as the royal wedding — but includes television anchors such as Katie Couric of CBS, said NASA spokesman Bob Jacobs.
With the story of Giffords remarkable recovery from the January shooting having been the focus of media attention in April, now more people are paying attention to the other parts of Endeavour's planned 16-day mission. The shuttle's main goal is to haul a $2 billion astronomy and physics experiment to the international space station.
$2 Alpha Magnetic Spectrometer
The shuttle's blastoff will also be watched by more than the usual number of physicists. That's because Endeavour will be carrying up a $2 billion particle physics detector known as the Alpha Magnetic Spectrometer, or AMS.
The AMS will be mounted onto the International Space Station, where, for a decade, it will collect cosmic rays — charged particles that zoom through space.
The AMS was designed to search for primordial antimatter created during the Big Bang, and the mysterious dark matter that makes up much of our universe.
One human being in particular is behind this project: Nobel Prize-winning physicist Samuel Ting of the Massachusetts Institute of Technology, who has been pushing to make it happen for more than 16 years.
After NASA agreed to launch this detector, Ting went out and raised money to build it with the help of hundreds of researchers in more than a dozen countries.
Ting did not give up even in the wake of the space shuttle Columbia disaster, when NASA officials said that things had changed and they had to cancel this flight. And in the end, NASA reinstated the flight.
Ting said no one knows what this instrument might discover.
"I mean, if you find what you predicted, it's not interesting," he said in an April interview. "The interesting thing is to destroy the current idea, to find something new."
This is also the next to last flight for the 30-year-old space shuttle fleet. And it is the final flight of the shuttle Endeavour, NASA's youngest orbiter, which has flown 116.4 million miles in 24 previous flights.
Giffords was wounded in the head in a mass shooting in January in her Tucson, Arizona, district that killed six people. Doctors have cleared her to travel to see the launch. She came for the April attempt, flew back to Houston to resume her rehabilitation work and even had dinner out with her husband.
President Obama and his family were among those who traveled to Kennedy Space Center last month hoping to see a launch. He met with the astronauts and visited with Giffords, but won't return Monday.
NPR's Nell Greenfieldboyce contributed to this report, which includes material from The Associated Press Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.