Discovery's delayed launching comes at a historic moment for NASA and its international partners. On April 12, NASA will mark the 30th anniversary of the first shuttle flight and the Russian space program will celebrate the 50th anniversary of Yuri Gagarin's launch on the first manned space flight.

Discovery's docking with the International Space Station will come just over 12 years after the Nov. 20, 1998, launch of the station's first component, the Russian Zarya module, and 10 years after the first three-man crew arrived aboard a Russian Soyuz spacecraft Nov. 2, 2000.

Since then, the space station has grown to include 13 pressurized modules and a huge solar array power truss stretching the length of a football field and tipping the scales at nearly 900,000 pounds. The lab has been continuously manned by rotating two-, three- and now six-person crews.

"I delivered the airlock on my first flight to space station," Lindsey said in a NASA interview. "It had just barely started and I remember thinking about all of the missions and all the components we still had to fly up there to fully build this thing out. At times it seemed like we were never going to get there. It was just, there were so many missions.

"When I look back at it now and see this fully assembled space station operating with six people and doing all the science and stuff like that, I'm just amazed at what this big team has accomplished and really excited about what it's going to accomplish in the future.

"Getting an opportunity to go up there again, which I never thought was going to happen, and see this fully assembled space station I've worked on most of my professional career here at NASA is just going to be something fantastic. I hope that the rest of the world appreciates what we have."

When Lindsey and his crewmates were named to the crew of shuttle mission STS-133, NASA intended Discovery's flight to be the program's final voyage, following a Bush administration mandate to finish the space station and retire the shuttle fleet by the end of fiscal year 2010.

That somewhat arbitrary deadline was relaxed a bit when Congress, worried about the possibility of schedule pressure on flight safety, promised an additional $600 million in funding to cover shuttle operations through the end of the calendar year. NASA managers later said internal cost-savings initiatives would allow shuttle operations to continue into early 2011 if necessary.

As it turned out, problems with a $2 billion particle physics experiment scheduled for launch aboard the shuttle Endeavour during the next-to-last fight in July 2010 forced NASA to revise the end-of-program shuttle manifest.

Because of work to replace the powerful magnet in the particle physics experiment, Endeavour's flight leap-frogged Discovery's, slipping to late November and eventually to Feb. 27, 2011. Discovery's flight, in turn, slipped from mid September to Nov. 1, in part to accommodate work to modify a cargo transport module for permanent attachment to the space station.

Discovery's launching then was delayed to Nov. 5 by bad weather and technical snags. The ship has been grounded since then because of the stringer cracks.

In the midst of Discovery's long launch campaign, NASA won political support for a third and final mission with the shuttle Atlantis to deliver additional supplies and equipment to the station. That flight, the shuttle program's final voyage, is targeted for launch June 28.

After the shuttle fleet is retired, NASA will rely on smaller unmanned Russian, European and Japanese cargo ships, along with new commercial spacecraft that are currently in development, to deliver the supplies and equipment needed by the space station to support a full-time crew of six.

"From a logistics standpoint, 2012 is going to be a real challenge for (the station program)," said shuttle Program John Shannon. "If there are delays in any of the new vehicles that are expected to deliver cargo to the station, that problem is just going to be exacerbated. It's hard to compare vehicles and capabilities. But my operations guy said one shuttle flight is roughly equivalent to about seven (Russian) Progress flights. So if you think about that, you can do pretty well on one shuttle.

"So getting to fly (Atlantis) late is going to give the space station margin from a logistics standpoint to keep six crew (members) up, to keep doing the research, to keep doing the utilization even if some of those new vehicles are delayed by some period of time."

If the Atlantis mission is not launched "and the new vehicles that are going to deliver cargo are delayed, and we end up having a logistics shortfall in 2012, and we have to go down to three crew, and we're not doing research, we have made a major error, in my opinion," Shannon said.

Faced with an uncertain budget, Shannon is struggling to reduce the shuttle workforce as required while maintaining flight safety and maximizing resupply of the space station.

Despite extensive layoffs, "the program is very healthy," Shannon said. "But I have a very high sense of paranoia that this is a very difficult time for the team, and we need to be incredibly vigilant, and any little noises that you hear you've got to go pay attention to and really make sure you fully understand what is going on. Because it's a very complex process and it's very unforgiving.

"So far, the team has done an outstanding job and we're going to continue to stay focused. The team really wants to preserve the legacy of the shuttle program and end on a really high note."

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