It takes about an hour to get ready to go to work in the morning. Then you stumble out of the house and get into your car. On the way to the office, you zone out a bit as you fight the morning rush. All in all, not much brainpower is needed.
Now imagine this: Getting up 8 to 10 hours before your drive to the office, then basically strapping onto an enormous missile that accelerates long enough to put you 115 miles up in the sky. For astronauts, having spent thousands of hours in training, and working with hundreds of people behind the scenes in NASA's Space Shuttle Program, it comes down to the most intense and exhilarating eight-and-a-half-minute commute ever.
Going to Work
At T minus zero: The space shuttle's three main engines have already fired 6.6 seconds ago, providing 1.2 million pounds of thrust (equivalent to 37 million horsepower). The temperature inside the nozzle is more than 6000 degrees Fahrenheit.
The shuttle's turbopumps spin at 37,000 rpm, feeding the thirsty engines with liquid hydrogen (at -423 degrees F) and liquid oxygen (-297 degrees F) stored inside the giant orange external fuel tank. And they pump at 1000 gal. per second, a rate that could empty an average family sized swimming pool in just 25 sec.
Standing about the same height as the Statue of Liberty but weighing three times as much, the two white Solid Rocket Boosters (SRBs) ignite in anger and push out a combined 6.6 million pounds of thrust (equivalent to 44 million horsepower). At 4.4 million pounds, the entire space shuttle stack lifts off with a power-to-weight ratio of about 18.4 horsepower per pound.
This is the point of no return. Once the boosters fire, they can't be shut off.
At T 8 seconds: The shuttle clears the launch pad and accelerates past 100 mph. Mission control switches from Kennedy Space Center at Cape Canaveral, Florida, to Johnson Space Center at Houston.
For the onlookers standing at the NASA Causeway six miles away (the closest public viewing area), you first see the shuttle rise and its white exhaust plume billow out of the flame trench in silence. Moments later you hear the rocket engines and feel the crackling noise pulsating past you. The sound pressure energy level at the launch pad is about 220 decibels (dB), and at a mile away, 135, where your hearing would still be damaged.
Human death occurs at around 200 dB due to intense vibration of internal organs. NASA says at 400 feet away, the heat will kill you. And at 800, the sound will. Watching the shuttle launch from six miles away doesn't seem too distant after all.
At T 2:06 minutes: The shuttle climbs past 28 miles above sea level, traveling at nearly 3000 mph. Also at this point, the two boosters are jettisoned and parachuted back down to the Atlantic ocean for recovery, about 140 miles off the Florida coast.
At T 8:30 minutes: After accelerating at nearly 3g (gaining 66 mph every second), the shuttle's Main Engine Cut Off (MECO) occurs. The orange external fuel tank is jettisoned and burns up over the Pacific ocean. Traveling at 17,000 mph (about Mach 26) and 65 miles above sea level, the two smaller rear rocket engines mounted on the Orbital Maneuvering System (OMS) pods fire. They push the shuttle higher into proper orbital altitude between 115 miles and 400 miles depending on the mission. Each 6000-lb. thrust OMS engine is fueled by gaseous nitrogen tetroxide and hydrazine, which combust instantaneously when they come in .
The astronauts have arrived at their office.
The Space Shuttle
NASA's Space Transport System (STS) consists of the orbiter vehicle (OV)—commonly referred to as the space shuttle—the external fuel tank (ET) and two Solid Rocket Boosters (SRB). There have been a total of six orbiters built: Enterprise (OV-101), Columbia (OV-102), Challenger (OV-099), Discovery (OV-103), Atlantis (OV-104) and Endeavour (OV-105). The Enterprise was used for flight tests within Earth's atmosphere and never orbited. The first space flight was done by Columbia in 1981, Challenger was lost during launch in 1986 and Endeavour was built to replace it at an estimated cost of $1.7 billion. The Columbia was also lost in 2003 during re-entry, leaving only three.
Wheels down, the orbiter stands at 56.6 ft. tall, with an overall length of 122.2 ft. and a wingspan of 78.1 ft. That is slightly larger than a commercial Boeing 737-700ER jetliner, with the exception of having 39 ft. less wingspan. And while the 737's maximum takeoff weight is 171,000 lb., the orbiter can weigh 258,500 lb. at liftoff when loaded with a maximum 63,500 lb. worth of cargo in its 15 x 59-ft. payload bay.
From a distance, the shuttle wears a white and black color scheme. Take a closer look and its outer skin is comprised entirely of thermal protection tiles. Because the airframe is made primarily of aluminum alloy, it can withstand only up to about 350 degrees F without melting. The vehicle needs shielding to sustain external temperatures between -200 degrees F to 200 degrees F during each 90-minute orbit around the Earth, and also as high as 3000 degrees F caused by friction when the vehicle re-enters the atmosphere.
The upper part of the shuttle wears white Low-Temperature Reusable Surface Insulation (LRSI) tiles. The bottom is covered with black High-Temperature Reusable Surface Insulation (HRSI) ones. Reinforced Carbon Carbon (RCC) panels protect the leading edges of the wings. The white tiles reflect as much heat as possible when pointed towards the sun, while the black ones shed heat faster to keep the vehicle cool during re-entry. Payload doors and the inboard section of the wings are protected by thermal blankets below the tiles. Each thermal tile measures approximately 6Ω8 in. square, and is about 1Ω3 in. thick, depending on the location, and is made mostly of silica glass fibers coated with blended glass powder. The tiles average about 2.4 lb. per cubic foot depending on the type and cost as much as $1000 each. There are approximately 24,300 tiles on the shuttle.
For landing, the space shuttle depends on three steel/aluminum struts and shocks filled with nitrogen gas and hydraulic fluid. On the nose gear, two 32 x 8.8-in. tires are inflated to 300 psi and can support 90,000 lb. together. Four 44.5 x 21-in. tires split between the two remaining main landing gears are inflated to 340 psi. Each is capable of carrying loads up to 123,000 lb.—nearly three times that of a Boeing 747 tire. Michelin in Norwood, North Carolina, makes these bias-ply tires specifically for NASA. Rated up to 258 mph, the nose gear tires are good for two landings, and the ones on the main landing gear are replaced after each use. Slowing the shuttle after touchdown are carbon brakes and a 40-ft.-diameter drag chute.
Aboard the Shuttle
A typical shuttle mission carries five to seven astronauts, but the vehicle can be configured to 11 seats if necessary. In orbit, the shuttle crew splits time between the upper flight deck, where most of the space-related activities occur, and the lower middeck, which acts mostly as living quarters.
On the flight deck, the left commander seat and right pilot seat have duplicate flight controls for use during ascent and descent. When in orbit, most of the shuttle's functions are controlled in the back panels facing the payload bay. The aft panels are divided into two sections. The ones on the left are for operating the orbiter. And the ones on the right are for operating the Remote Manipulator System (RMS), a 50-ft. articulating arm with elbows and wrists that can lift and retrieve cargo, or act as a platform for astronauts during their space walks. There are more than 2020 displays and controls on the flight deck, 100 times more than in an average automobile.
At Houston's Johnson Space Center, I tried my hand-eye coordination talents in a simulator, docking the orbiter with the International Space Station as well as lifting a piece of cargo out of the payload bay. With help from Alan Fox, a 29-year NASA veteran and lead rendezvous instructor, and Fernando Galaviz, a 3-year NASA employee and facility support engineer, I was able to pulse the Shuttle's Reaction Control System (RCS) composed of 16 front and 14 aft small thrusters to guide and connect the vehicle's airlock with the one on the space station...multiple times without needing to reboot the computer! Fox commented that these small thrusters are so precise and amazingly accurate that the astronauts mostly do manual flying without much computer assistance.
Grabbing cargo out of the payload bay with the RMS is another story. Because of the three-dimensional nature of the exercise, you have to rely on video cameras mounted on the robotic arm. Understanding the correct viewing angles and how you control the arm's motion in different spatial planes is crucial. Thanks to Bill Miller, a 28-year NASA veteran and shuttle robotics instructor, I did not damage or lose any precious cargo in space.
On the shuttle's middeck, up front in the nose, resides a wall full of liquid-cooled avionics instruments. Immediately behind are storage lockers for personal items and food. Next to the orbiter's door hatch on the left is the "space toilet"—something to experience and hard to describe, and we'll just leave it at that. On the right is the "kitchen" where the astronauts prepare food. Throughout the crew compartment, there are countless Velcro strips for fixing items in place so things like pens or clipboards don't float away. Also along the walls in the middeck are spots for the crew to hang their sleeping bags at night. In total, there is 2325 cu. ft. of pressurized living space aboard the orbiter.
Astronauts can heat up their thermal stabilized food packets to 175 degrees F in the oven—typical eating temperature at home—or inject them with hot or cold water. According to Vickie Kloeris, a 25-year NASA veteran and manager of International Space Station food system, there are some 180 different menu items from which to choose. One of the crew's favorites is tortillas since they can wrap different fillings inside or dip them into various foods. And yes, Tang is still available!
How does space food taste? At Houston's Johnson Space Center, I tried out chicken fajitas, macaroni and cheese, and even a cherry blueberry cobbler. All are good, tasting similar to reheated frozen foods from your local market. Kloeris notes that eating in space is like having a head cold. Because of weightlessness, fluids inside your body rise into your head so you feel congested, dulling taste and smell senses. Astronauts bring plenty of salt, pepper and spices to liven up their entrees.
Most space shuttle missions last approximately 10 days, but plumbing and electrical upgrades allow the orbiters to stay in space for up to 28 days—and no showers, just sponge baths.
The shuttle is unpowered and acts as a glider when it returns to Earth and you get only one shot at it. With the help of Darrel McGregor, a 26-year NASA veteran and simulation supervisor at the Johnson Space Center's full-motion simulator, I received a passing grade for my five tries at landing the vehicle. No one was hurt or major damage done. The computer assist via the head-up display guided me to the runway with precision. And like driving, keeping the shuttle flying smoothly means anticipating where you're going and looking ahead through the orbiter's forward cockpit window, and on a LCD panel where it shows your projected glide path versus the ideal one. The control stick is easy to operate and has a nice progressive off-center resistance.
Aboard the real shuttle in orbit, when it is ready to return home, it starts the reentry process by flying upside down and firing its RCS thrusters to turn itself around with the tail heading first. Then the bigger OMS engines ignite for about three minutes, decreasing the speed by about 200 mph to just under 17,000 mph. At this point, the orbiter is over the Indian Ocean.
In the next 25 minutes as the shuttle enters the upper atmosphere, the RCS thrusters fire again to flip the vehicle over with its nose pointed forward and its belly facing Earth. Since all the aerodynamic control surfaces are still ineffective, the orbiter must rely on the RCS to maintain a 40-degree nose-up angle-of-attack nose-up as it descends to an altitude of 75 miles. Then the RCS is also used to perform four steep bank-and-roll S-turns to scrub off more speed. This is when the orbiter is feeling the 3000-degrees F heat buildup from friction with the atmosphere.
At about 140 miles away and 150,000 ft. of altitude, a navigation beacon guides the shuttle to the runway. Continuing to decelerate to about 1800 mph (Mach 2.5), the orbiter becomes a glider at around 83,000 ft. At 25 miles out, the commander takes control and flies around an imaginary cylinder (four miles in diameter) to line up the runway. On final approach, the shuttle is dropping like a brick at more than 166 ft. per sec., almost 20 times the sink rate of a commercial airliner. It touches down at around 230 mph and, with the drag chute deployed, takes about 5500 ft. to stop.
Not a bad day's work. The shuttle astronauts get to experience the most thrilling ride ever by commuting in mankind's fastest machine on wheels. And best of all, no traffic!
Special thanks to NASA and its public affairs office for assisting and arranging access to the Space Shuttle Program at Johnson Space Center and Kennedy Space Center.
A quick astronaut hello before getting to work.