An Extraordinary Movie
An Extraordinary Movie On October 7th, NASA TV plans to broadcast the first
live video from a space shuttle's fuel tank as it soars into
Earth orbit on the belly of Atlantis and falls back again.
Sept. 26, 2002: I love the movie Apollo 13. I've seen Jim Lovell pilot that balky lunar module with Earth lurching back and forth through the windshield about a dozen times--and it's still thrilling. From the exploding oxygen tanks ("Houston, we have a problem...") to the CO2 crisis to the breathless re-entry ... the tension never stops.
But the best part of Apollo 13, the most thrilling scene, has nothing to do with the accident. The best part, in my opinion, was the launch.
When Lovell's Saturn V rocket blasted off the pad in Florida--seven million pounds of pure power soaring toward space with angelic voices singing in the background--it gave me goosebumps. The footage revealed what I had never "got" from books: The Saturn V was terrifyingly powerful. No one who saw it lift off could imagine spaceflight was routine.
Above: A Saturn V moon rocket lifts off pad 39A in Cape Canaveral on July 16, 1969. [more]
On October 7th we get to find out.
That's when the space shuttle Atlantis (STS-112) is slated to blast off from Cape Canaveral on a mission to visit the International Space Station. For the first time ever, a camera attached to the shuttle will record the ascent and transmit images live to NASA TV. The point of view will be similar to the launch scene in Apollo 13.
The camera--called the "ET camera" around NASA--will be mounted near the top of the shuttle's burnt-orange external fuel tank (ET). It will look down toward Atlantis's nose, the 40 degree field of view encompassing most of the fuel tank, one of the white solid rocket boosters (SRBs), and the shuttle itself.
The camera will "go live" about 15 minutes before liftoff. Nothing much will happen during that time--consider it a dramatic pause. Then, at T-7 ("tee-minus-7") seconds, ground controllers will ignite the shuttle's main engines (first) and the solid rocket boosters (second). SRBs always start second because, once they're lit, they can't be turned off again.
Above: Space Shuttle Atlantis (STS-110) lifts off in April 2002 on a previous mission to the International Space Station. [more]
Eight giant bolts hold down the SRB's. As soon as the boosters are ignited (T=0 on the countdown clock) the bolts will be released and Atlantis will rise off the pad. At that moment, the shuttle's two solid rocket boosters and three main engines produce 7.8 million pounds of thrust--more than Lovell's Saturn V moon rocket. (The shuttle's engines contribute 29% of that thrust, the SRBs 71%.)
During those early moments, the camera will see bright flames and a lot of smoke. The grayish-brown clouds are exhaust from the SRBs. The white stuff is water vapor. Water is sprayed across the launch pad, in part to prevent fires and also to mute the thunderous noise. The spray is vaporized by heat from the SRBs and the engines. The engines themselves spew water as a result of oxygen-hydrogen combustion, thus adding to the steam.
It takes about seven seconds for the shuttle to clear the 247-ft tower and its 100-ft lightning rod. In that short time the shuttle's engines and rocket boosters consume more than 150,000 pounds of fuel. Hard to believe? Just think about all that fire and smoke....
At first Cape Canaveral will recede smoothly beneath the shuttle; then, around T+20 ("tee-plus-20") seconds, the ground will suddenly spin. That's the roll maneuver. The entire shuttle "stack" turns so the orbiter lies underneath the fuel tank. This is done for many reasons, e.g., it reduces stress on the shuttle's delicate wings. It also lets astronauts see the horizon, giving them a reference point should the mission have to be aborted and the shuttle forced to land
Pay close attention during the first minute of ascent, you might spot clouds swishing by the shuttle. There won't be any warning because the camera points down, not up. These cloud flybys will stop as soon as the shuttle climbs above the tropospheric cloud layer, 3 to 6 miles high.
One of the most interesting parts of the movie comes two minutes after launch when the shuttle is about 28 miles above Earth and the SRBs run out of fuel. Explosive bolts separate the empty boosters from the external tank, and motors (with their own little exhaust) push the boosters away from the shuttle. SRBs fall back to Earth, but they don't crash. Parachutes lower them gently to the Atlantic Ocean, where they are retrieved for use in future missions.
With the SRBs gone, the shuttle relies solely on its three main engines for propulsion. During the next six minutes, they will accelerate the spaceship to 17,500 mph. The engines drain the fuel tank at a rate of 60,000 gallons per minute--fast enough to empty a family swimming pool in 10 seconds flat.
When the shuttle first leaves the launch pad, it flies vertically, but the spacecraft gradually levels during the ascent. Sometime around T+4 minutes, the shuttle become horizontal enough for the camera to see the distant curved horizon of Earth. The sky will appear space-black--a lovely view. NASA insiders would say the shuttle is almost "on orbit" ... which means it's time for the grand finale.
At T+8 minutes, with the shuttle 52 miles above Earth, the ET finally runs out of fuel. There's no reason to carry a huge empty tank in orbit, so ground controllers jettison it. The tank will fall back to Earth, with the camera attached, slowly tumbling as it goes. Eventually it will burn up over some deserted stretch of ocean, although the camera won't last that long. NASA expects the live feed to stop about six minutes after ET separation or until the tank moves out of range, whichever comes first.
Like any good movie, the ending of this one is a mystery. What's the last thing the camera will record? No one knows. Will it give you goosebumps like Apollo 13? Will you ever watch NASA TV again? There's only one way to find out: tune in on Oct. 7th and see for yourself.
Editor's note: This movie, unlike ordinary films at the theater, might be delayed by weather or other factors. If you have a copy of Apollo 13, keep it handy. You might need a backup plan.more information
NASA TV viewers can hitch a virtual space shuttle ride -- (NASA) at the end of this press release is a link to an animated view of what the shuttle movie might look like.
NASA TV--many cable TV suppliers offer NASA TV; you can also watch it live on the web.
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