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NASA Exploration Mission-1 – Pushing Farther Into Deep Space

In the next eight minutes you’llexperience a twenty-five-and-a-half day mission from roll out to recovery. Thefirst integrated flight test of the Orion spacecraft and the Space LaunchSystem rocket, launching from the Kennedy Space Center, is about to unfold.

This is the first of many missions to come that will use the deep-spaceexploration system to prepare our team, our ship, and our astronauts for humanoperations in deep space. Rollout from the Vehicle Assembly Building signals that launch is near.

Sitting atop the mobile launcher the crawler transporter moves along the crawler way towards the historic launch pad 39b at the KennedySpace Center at a top speed of 1 mile an hour. After traveling over 4 miles,the rocket and spacecraft climb up a ramp and are positioned over a flametrench. Once in position, the mobile launcher is lowered onto support postsand the crawlers roll away to a safe distance.

 Final checks are performed atthe pad, including crew cabin closeout via the access arm sitting over 300 feetabove the surface of the launch pad. The launch date is set and the teams areprepared for the mission that is about to occur. At sunrise on launch dayengineers in the launch control center have already powered up the spacecraftin the rocket and loaded the core stage and upper stage with cryogenic fuel.

 Aslaunch window open approaches final checks are performed and when allsystems are go terminal countdown is initiated. The big physics of launch areabout to be put on full demonstration. Umbilical plates weighing hundreds ofpounds await their cue to retract to clear the path of the rocket at liftoff,some mounted on arms the size of tractor-trailers.

The mighty core stageengines are prepared for engine start as they are thermally conditioned for anonrush of cryogenic fuel in the heat of ignition. At T-minus 15 seconds soundsuppression is activated, cascading water into the flame trench to dampen theacoustic shock, and as the core stage engines achieve full throttle shockdiamonds appear.

At booster ignition the flame trench is flooded with fire. At first motion all umbilical arms are retracted and the rocket clears thetower in just seconds. At liftoff the vehicle produces 8.8million pounds of thrust and lofts the vehicle weighing nearly 6 million pounds and standing 32 stories tall to orbit. Propelled by a pair of five-segment boosters and four liquid engines, therocket achieves maximum dynamic pressure only 90 seconds into the mission–theperiod of greatest atmospheric force on the structure of the rocket.

Thousandswill gather in Florida to watch our ship get smaller and smaller and leave theSpace Coast behind. Approximately two minutes into the missionthe boosters will have consumed all of their solid propellant and are safelyjettisoned. The rocket will continue on guiding itself to orbit with magnificentprecision.

Just three minutes into the mission the service module fairings arejettisoned to lighten the vehicle and expose Orion solar arrays. Just 40seconds later the launch abort system is also jettisoned. It is no longer needed:Orion could safely abort at any time. Once at the desired velocity target the core stage engines are shut down and the core stage separates. The interim cryo propulsion stage with Orion will continue to orbit the Earth. Along the way they will past through the altitude of the International Space Station at250 statute miles. During this first orbit the solar arrays are deployed sothat Orion no longer needs battery power.

 It can now produce its own power. Following solar array deployment, the arrays are positioned into a load-bearing configuration to prepare for the perigee raise maneuver. The raisemaneuver will ensure an Earth orbit and use the thrust provided by the interimcryo propulsion stage. Once the perigee raise maneuver is completeOrion systems are checked prior to committing to the translunar injectionor TLI maneuver.

The TLI maneuver must be successfully completed to depart Earthorbit. The TLI burn is approximately 20 minutes in duration and increases thespacecraft’s velocity over 9,000 feet per second–a speed change faster than ahigh-powered rifle bullet travels. Following TLI, Orion is committed to alunar trajectory just one-and-a-half hours after launch.

 Once complete, thespacecraft adapter will remain with the interim cyro propulsion stage and theywill separate from Orion. As Orion departs low-Earth orbit it will flythrough the orbital debris field encircling the Earth. Past the globalpositioning navigation satellites, past the communication satellites ingeostationary orbit, and through the Van Allen radiation belts on into the deepspace radiation environment. Orion is now entering in outbound coast phase. Thespacecraft is uniquely designed to navigate, communicate, and operate in thisdeep space environment. The outbound coast of the Moon will takeapproximately 4 days.

 As Orion approaches the Moon, the service module will be usedto perform a critical lunar gravity assist maneuver, allowing the ship toenter a distant retrograde orbit about the Moon. The Moon will get larger andlarger in the window and at closest approach Orion will be just 62miles from the surface of the Moon.

 As the spacecraft flies around the far sideof the Moon we will lose all communication back on Earth and for aperiod of time Orion will be on its own. Mission Control will await acquisitionof signal and as we lock on a new generation will see their first Earthrise. The spacecraft is now in the distant retrograde orbit, where itssystems will be tested in the deep space environment for over a week. Along theway our ship will travel farther from Earth than any human-capable spacecrafthas ever gone.

At the farthest point Orion will be some 1,000 times fartherfrom Earth than the International Space Station, at over 270,000 miles away. Teams in Mission Control Houston and at Naval Base San Diego will prepare for Orion’sreturn home and the recovery ship will set sail for the recovery zone in the Pacific Ocean. Orion will exit the distant retrogradeorbit with another lunar gravity assist and service module engine firing.

 Alongthe way the trajectory will be adjusted to target the Earth’s thin atmosphere atover a quarter-million miles away and ensure precision landing in the PacificOcean following a direct entry. During the coast home Orion will maintain the desired tail to Sun attitude to optimize spacecraft cooling and maximizepower production in the deep space environment. Another 4 days’ returncoast home to Earth. As our home planet fills the windows of Orion an important contribution from our European partners, called the servicemodule, has done its job.

 The service module is jettisoned and separates. Following separation the world’s largest heat shield will be oriented into the direction of travel to prepare for entry interface and analtitude of 400,000 feet. At entry interface, Orion will hit theEarth’s atmosphere traveling at a speed of 24,500 miles an hour and decelerate up to nine times the force of gravity. The heatshield will protect the spacecraft from temperatures half as hot as the surfaceof the Sun–approaching 5,000 degrees Fahrenheit.

 Orion will continue to decelerate, pass through the sound barrier, and announce its arrival to the waiting recovery team with a sonic boom. Following peak heating a protective thermal cover that sits over theparachutes will be jettisoned. This begins a series of parachute deployments.The drogue chute deployment series is designed to stabilize and slow thespacecraft in a period of less than 20 minutes–Orion will slow from the speed of Mach 32 to 0 at splashdown.

The three mainparachutes will deploy and slowly unfurl and suspend the 22,000 pound capsule andallow it to gently descend to the surface of the ocean. After 25-and-a-halfdays, and a total distance traveled exceeding 1.3 million miles, a precisionlanding within eyesight of the recovery ship. Following splashdown Orion willremain powered for a period of time as Navy divers approach in small boatsfrom the waiting recovery ship.

 After a brief inspection for hazards, the diverswill hook up tending lines and a towline. The capsule will be then towedinto the well deck of the recovery ship, and once the capsule clears the sterngate, the gate will be closed, the well deck will be drained, and we will bringour ship home. We invite you to follow along at www.NASA.gov/exploration

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