About three months ago, we ran a piece here about the Shuttle launch. It didn’t fly then, but it’s scheduled to go shortly. At 12:30 am EDT, the astronauts were awakened to begin pre-launch activities. If you’re reading this Tuesday morning, check your watch. If it’s 10:39 am or earlier, RUN, do not walk, to your nearest television.

Most recently, on July 14th, an on-going problem with the Shuttle’s fuel sensors forced another flight cancellation. Lockheed Martin Space Systems builds the Shuttle’s fuel tanks at its Michaud plant in New Orleans. Michaud was “thrust into controversy,” according to an article here, “2½ years ago when a piece of insulation foam broke free from an external tank and smashed into the shuttle Columbia. The foam left an undetected but fatal gash in the orbiter’s wing. The spacecraft was destroyed on its trip home two weeks later, and all seven of its astronauts died.”

The article continues, “For the past two years, the 2,100 people who work at the eastern New Orleans plant have been redesigning faulty portions of the tank, mostly on its exterior. Wednesday’s aborted launch of Discovery would have been their first chance since the tragedy to show the world that their products are safe for flight.”

Well, today—hopefully you’ll read this in time to see it—those 2,100 people will have another chance.

For a more in-depth look (compared to what you’ve seen on national news) at the ECO (engine cut-off) sensors, see this article at SpaceFlightNow.com. CNN’s roving Shuttlehead, Miles O’Brien, among others, has reported that the craft uses four such sensors. While this is true, they’re part of a much larger system of 24 propellant sensors in the craft’s external fuel tank—12 each in the oxygen and hydrogen sections. The ECO sensors are part of a backup system designed to prevent the engines from shutting down too early (resulting in an aborted mission and a lot of panicked people) or run too long (“draining the tank dry with potentially catastrophic results”).

According to the SpaceFlightNow article, “NASA’s original launch commit criteria required three operational ECO sensors for a countdown to proceed. But in the wake of the 1986 Challenger disaster, the LCC was amended to four-of-four because of concerns two sensors could be knocked out by a single failure in an upstream electronic black box known as a multiplexer-demultiplexer. The single-point failure was corrected during Discovery’s last overhaul, but the four-of-four launch rule remains on the books.”

Tuesday’s flight will be a particularly tense moment for NASA’s new Administrator (as of April 14th), Michael Griffin, whom CNN’s Lou Dobbs interviewed on this evening’s show. Griffin, who served as NASA’s Chief Engineer early in his career, said: “First of all, these sensors are normally not used at all. There has to be at least one failure of our system before these sensors come into play. If they come into play, we need two of them. So, if we launch with three, then it would take a second failure to take out one of the sensors and we’d still be okay—which means we’re two failure-tolerant.” Griffin continued, “When we fly with three out of four sensors working, all we’re really doing is going back to the original launch commit criteria that this design was based upon. Discovery is flying for the first time with an electronic box where all four sensors are completely independent from the other.”

(For a relatively brief history of Shuttle changes over the years, see this page.)

When Discovery Mission STS-114 flies, today or within an upcoming launch window, it will be the first time a Shuttle has flown since the Columbia Disaster.

Even First Lady Laura Bush will be on-hand at Kennedy Space Center to watch the launch from the VIP viewing site.

(See this guy’s page for a wonderful selection of KSC-related photos. Okay, I didn’t need to see him flipping burgers in his shorts, but the Cocoa Beach condo must be a great place. Thanks, Anonymous Man, for your photos of KSC, the activities there, and historical displays. If only everyone could take “What I did on my vacation” photos like this…)

The Space Shuttle: this is greatness. Human greatness. This is America—I hope to God—at its finest. This is engineering at mind-boggling levels of creativity, commitment, complexity, and magnitude. This is The Greatest Show On (and Off) Earth. Reality isn’t Brat Camp. You want Reality TV? Strap a bunch of brave and brilliant PhD butts to rockets, then hurl ‘em into space on national television. Now that’s reality.

Even if you’re not thrilled about the Space Program, show your support for the people involved in it through television ratings. Please, if there’s any way you can, watch the launch. And if they postpone it again, don’t give up.