Behind the scenes at the last Atlantis launch: What to watch for as the shuttle program ends
The scheduled launch of Atlantis space shuttle, with a reduced crew of four, will be all over television today. It's the 135th and final flight in the fabled 30-year history of America's space shuttle adventure.
We are participating in the NASA Tweetup this week with unique access to the space center and NASA experts. So in anticipation of the launch we decided to gather gobs of details about what you won't hear or see on TV, courtesy of numerous interviews at the Kennedy Space Center, most especially with the veteran and patient American astronaut Doug Wheelock. Plus we have some inside NASA launch videos below:
While you were sleeping, technicians fueled the amazing mechanical monster. Flight managers made that decision at 2 a.m. Eastern, hoping to find a clear spot of weather between today's predicted storms.
The rockets are so huge, they will take more than a half-million gallons of liquid oxygen and nitrogen. If you laid Atlantis and its rockets down on a football field, they would reach from one goal line beyond the far 30-yard line.
And these engines have a voracious appetite. At T-minus three hours, technicians will have loaded 150,000 gallons of liquid oxygen and 345,000 gallons of liquid nitrogen. The LOX alone weighs 10 pounds per gallon. So there's 1,500,000 pounds right there.
Most of this fuel volume will be consumed in the 8.5 minutes it takes to reach orbit.
Attached to the huge rust-colored tank (the color is thermal protection, no longer painted white, which saves 600 pounds) are those twin solid rocket boosters. Each of those long white cannons weighs 1.5 million pounds. They are reusable. (See video below for a rocket's eye view of the last launch.)
Altogether depending on payload, the rocket-shuttle combo weigh just under five million pounds, even more than the combined weight of Congress after lunch. Did you know that together the package is called the shuttle. When Atlantis returns home alone, weighing less than 250,000 pounds, it's called the orbiter.
There are several holds or planned pauses built into the countdown. The main reason for these: To let human minds catch up with the monitoring and analysis of their computers.
At T-minus 15 seconds, 350,000 gallons of water flood the area beneath the shuttle. But not just, as you might think, for the heat. It's to subdue a sound pulse created by the engines' beyond deafening roar.
Those sparks you might see beneath the main engine nozzles are intentional to burn off any hydrogen fumes. At T-minus 6.6 seconds the main engines ignite. But the entire assembly remains bolted to the pad.
As the thrust from the three shuttle engines builds, it actually moves the tip of Atlantis three feet over and then, in slow motion, back to vertical. If all is well with the main engines, eight explosive bolts tethering the machine to earth are blown. (Watch for small puffs of white smoke at the rocket base in the bottom video here.)
And the solid fuel boosters ignite.
These twin towers of power have no throttle. No controls. They know nothing but full blast. It's basically a pair of two-minute controlled explosions out the rear.
As Wheelock puts it, "Once you light those babies, you're going somewhere."
Together at liftoff the engines provide in excess of six million pounds of thrust and the burning fuel reduces the weight it's carrying by thousands of pounds per second.
Watch this cockpit view video of a launch and see how even the tightly-tethered crew is firmly jostled. (More text below)
Ever wonder why shortly after launch as it starts its flight up the East coast, the shuttle always turns on its back? "Houston, Atlantis roll program." One, that movement aligns rooftop antennas with the myriad of tracking stations below.
But since the shuttle has wings with lift, it wants to fly on its own. Not a good thing when tethered to rockets, or until journey's end. Turning upside down transforms that wing lift into negative force, saving strain on connections.
You're likely to hear a myriad of other terms in the radio chatter. "Go at throttle up," meaning all is well and the engines can be returned to full thrust after passing through the sound barrier.
"CDR" is the flight commander, Chris Ferguson. "PTL" is the pilot, Doug Hurley. "MS1" and "MS2" are the mission spoecialists, Sandra Magnus and Rex Walheim.
At two minutes-five second comes "BECO," booster engine cutoff. Those twin rockets that have been burning 11,000 pounds of fuel per second are discarded by explosive bolts. However, since their burning fuel will carry them four miles higher, mini-rockets steer the spent engines away from the shuttle.
In the nose of these rockets is a trio of parachute packages that open, first, to right and steady the falling cylinders, then slow them more and finally take them to a splash landing in the Atlantic, where two recovery ships are already waiting 120 miles off Jacksonville.
If you've ever wondered what it's like to fall about 14 miles, check out this video from NASA booster cameras and then read more below:
You might also hear "Negative return," meaning Atlantis is too high and too far away to return to the Cape if something went wrong. NASA has emergency landing fields around the globe.
"MECO," main engine cutoff, meaning they've made it into orbit. Shortly after the boosters fall away, the shuttle is traveling 4,000 miles an hour. Less than two minutes later it's going Mach 8, about 5,700 miles an hour. Thirty-five seconds later it's increased to 6,600 miles an hour.
Before six minutes of flight it's hustling along at Mach 13, 9,000 miles an hour. A minute later 13,000 miles an hour. One more minute and they're doing 17,500 miles an hour, Mach 25. (And, yes, during launch all astronauts wear diapers.)
Here's another sense of space speed. In orbit, they have a sunrise or a sunset every 45 minutes. In its 293 days in space Atlantis has seen 4,648 of each with temperature swings of several hundred degrees.
Wheelock recalls casually while returning to Earth one time, he looked down and saw Seattle. Nineteen minutes later he was in Florida -- just one mile from where Atlantis now sits for her next -- and last -- adventure.
-- Andrew Malcolm
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Photo: Andrew Malcolm / Los Angeles Times (Atlantis countdown clock at T-minus 11 hours and holding, Atlantis on Launch Pad 39A can be seen just to the right of the clock, three miles away, July 7); Andrew Malcolm / Los Angeles Times (Wheelock by Atlantis, July 7).
Videos courtesy of NASA TV.