It has been more than a generation since NASA
built a spacecraft to transport astronauts into space but man is now ready to take another
giant leap in space exploration. NASA is planning on sending humans far further than they have ever been before by building the Orion Spacecraft. The Orion spacecraft is designed to meet the
evolving needs of human deep space exploration for decades to come. Humans have not ventured into space beyond Low Earth Orbit since man's landing on the moon. Low Earth Orbit is an orbit around the Earth with an altitude ranging from 160 km to 2,000
km above the earth. Low Earth Orbit is where the Space Shuttle flew and the International Space Station now flies. It is where spy satellites and Earth observing satellites fly. It is
where the Hubble telescope and many communication satellites fly. It is also where most of the
"space junk" is located. Orion breaks through this Low Earth Orbit and ventures into interplanetary space on extended duration deep space missions. Destinations include
near-Earth asteroids, our own Moon, the moons of Mars and eventually Mars itself. The Orion
Multi-Purpose Crew Vehicle (MPCV) provides an entirely new human space exploration capability, beyond low Earth orbit. In addition to deep space missions, Orion
is also capable of transporting crew and cargo to the International Space Station. It is
also a back-up system for the ISS. It can rendezvous with a lunar landing module and
be a departure point in low-Earth orbit from which crews can venture out to and return
from the moon and Mars. Orion can remain docked at the International Space Station for up to six months. It also has the ability to stay in orbit around the moon unattended,
without an astronaut on board, for the duration of a lunar surface visit that could last up
to six months. Orion consists of a cone-shaped Crew Capsule,
a Service Module, and a spacecraft adapter. Other components include a Space Launch Abort
System, and for extended interplanetary travel, a Deep Space Habitat.
Orion features dozens of new technological advancements and innovations, many of which
were derived from experience with the space shuttle program, and are incorporated into
the spacecraft's design. Even new manufacturing techniques have been developed for Orion such
as a self-reacting friction stir welding system which provides stronger and more durable joints.
Some of the component parts are produced using 3D printing including a baffle and rocket
injector. Since Orion is a re-useable craft, its life support, propulsion, thermal protection,
and avionics systems have been developed so that they can be upgraded as new technologies
and innovations become available in the future. Orion's heat shield is an extremely critical
part of the spacecraft. Orion's capsule shape allows it to land in water, like the Apollo missions did, when it returns to earth. A capsule without wings makes it a lot simpler
to provide heat protection during re-entry. Due to speeds of around 27,000 MPH required for re-entry from deep space missions, Orion's Heat Shield needs to protect the capsule from temperatures near 5,000 degrees Fahrenheit, more than half of the surface temperature
of the sun...temperatures capable of melting iron, steel or chromium. The heat shield's skeleton gives the spacecraft the strength to withstand the craft's impact
with the water's surface when it splashes down in the Pacific Ocean. Orion's heat shield, at 16 1/2 feet in diameter, is the largest heat shield ever constructed.
A heat resistant material, called AVCOAT, covers the heat shield. This is a glass-filled
epoxy-novolac honeycomb system matrix applied to the heat shield skeleton. The honeycomb
shape gives the heat shield strength and resistance to cracking. Avcoat is the only man-made ablative
material that exists today that can handle the extreme temperatures of high speed re-entry
following a deep space mission. The heat shield is designed to be consumed as Orion re-enters earth's atmosphere. The ablator heat shield material therefore burns off during re-entry,
carrying heat away from the capsule's structure, and providing a layer of cooling between itself
and the capsule. Since the Space Shuttle could never have left low earth orbit with its wings
and tail, its heat tiles worked fine for heat the levels that it encountered during its
returns from low earth orbit. But tiles like on the Space Shuttle would not be strong enough
for Orion's heat shield which encounters heat levels significantly hotter than the
shuttle ever did. The non-heat shield surface of the capsule
however, called its back shell, is covered with AETB-8 tiles which are the latest generation
of heat shield tiles. These tiles also protect the capsule from the debris environment or space junk that Orion could encounter while in low earth orbit.
Up to now, long duration spaceflights for Americans have lasted about six months and
have taken place entirely within low-Earth orbit. Since Orion takes astronauts to destinations
beyond low-Earth orbit, astronauts will travel outside the protective shield of the Earth's
atmosphere and magnetic field. Without the protection that the Earth provides, the crew and systems of Orion would be exposed to the full spectrum of space radiation. As astronauts venture into interplanetary space they will also have to cross the Van Allen Belt, a tightly
packed field of radiation around the Earth that protects earth from charged ions. NASA
has had to develop methods of protection from significantly more radiation than astronauts
have experienced in the past. Orion will be able to use materials already stored inside the spacecraft such as water, food, equipment and other supplies which have been shown to
offer additional protection against radiation in addition to the spacecraft itself. Since
these items are already stored near the heat shield, this provides a temporary shelter
in the aft bay close to the heat shield. Several radiation sensors are located on board to
record levels of radiation. Orion may look a lot like the Apollo capsule
in shape but the comparison stops there. Orion is larger than Apollo and has been referred to as Apollo on steroids. Whereas Apollo carried 3 astronauts, Orion can carry as many as 6 crew members to and from the International Space Station and is capable of landing 4 astronauts on the moon. The crew capsule can withstand the vacuum
of space and keeps out salty ocean water upon returning to Earth protecting critical components.
It provides a habitat for the crew, storage for consumables, and holds the majority of
Orion's electronics. The crew module is the only re-useable part of Orion that returns to Earth after each mission. This is the green interior pressure vessel
that makes up the core of the crew capsule. The Capsule's Avionics are described as
the "brains" of the spacecraft. Orion has advanced systems in electrical power, flight control, life support, and communications. Due to the extreme distances of long duration
missions, Orion's advanced navigation and tracking systems will enable Orion to maintain orientation and communication with the Earth. Its systems move data at a rate 1,000 times
faster than systems on the shuttle and the ISS. The capsule contains what is called a "glass cockpit". It is a digital control system evolved from several airplane cockpit designs including Boeing's 787 multifunction flat-panel
multicolor displays. It is outfitted with an "auto-dock" feature allowing the spacecraft
to dock with the International Space Station automatically, yet has a provision for the
flight crew to take over in an emergency. The Orion Service Module serves as the primary power and propulsion component of the spacecraft, and is discarded at the end of each mission.
It carries rocket engines for propulsion and large solar panels for generating electrical
power. It is attached below the crew capsule, and provides life-sustaining water, oxygen
and nitrogen needed for a habitable environment and maintains the temperature of the vehicle's
systems and components. Both the Crew Module and Service Module are constructed of the aluminum lithium alloy that was used on the space shuttle's external
tank. 14 foot protective fairing panels cover the
capsule and service module protecting those components during launch and are jettisoned
after the spacecraft reaches 560,000 feet above the earth. Orion's Ultra-Flex solar arrays support all of the electrical power needs for both
earth-orbiting and deep space missions. Rechargeable lithium-ion batteries store that power for
use when the vehicle is away from sunlight. The solar arrays are 10 times as rigid as
conventional rigid panel arrays, yet are micro-thin. Each of the 2 circular solar arrays spans
19 feet in diameter and provides over 6,000 watts of power ... enough to power six three bedroom homes. The spacecraft adapter connects the Crew Capsule
and Service Module to the launch vehicle and protects service module components during
launch and ascent into orbit. The Orion MSA diaphragm is a light weight
composite structure that protects astronauts in the crew capsule from hazardous gases produced
by the upper stage launch engines. It sits between the propellant stage of the rocket
and the crew capsule. The crew capsule and service module join with
a Deep Space Habitat for longer deep space missions, which can last up to 900 days. The
crew quarters of the Deep Space Habitat provide the crew with radiation and storm shelter
protection during Solar Particle Events. They provide, in addition to living quarters, storage
areas, science stations, and a galley for food preparation, including a microwave and
refrigerator for food heating and storage. Upon returning to Earth after deep space missions the capsule will splash down in the Pacific Ocean. Once the heat shield has done its job
of getting Orion through the atmosphere, parachutes will take over for the landing. A forward
bay cover protects the crew during launch, flight, and re-entry, but must be jettisoned
to allow Orion's main parachutes to deploy. After returning from a deep space mission,
the forward bay cover is jettisoned at an altitude of 23,000 feet.
Drogue parachutes initially slow down the spacecraft and then three smaller pilot parachutes
are deployed. Next come the three main parachutes. They measure 116' across and weigh 300 pounds
each and together can cover a football field. In the event of emergency on the launch pad
or during launch, an escape system called Launch Abort System separates the Crew Module
from the launch vehicle using a solid rocket-powered launch abort motor. This abort motor is more
powerful than the Atlas booster that launched astronaut John Glenn into orbit in 1962. The
launch abort system, positioned on a tower atop the crew module, activates within milliseconds
to propel the crew module 500' in the first 3 seconds and to safety in the event of an
emergency during launch or climb to orbit. The Launch Abort System consists of 3 motors:
The Main Abort Motor, The Attitude Control Motor, and The Jettison Motor. Orion is launched into space by NASA's Space Launch System, an advanced, heavy lift vehicle
which provides an entirely new capability for science and human exploration beyond Earth's
orbit and into interplanetary space. The SLS is NASA's first exploration-class vehicle
since the Saturn V rocket took American astronauts to the moon over 40 years ago.
The core (center) stage stands over 200 feet tall with a diameter of 27.5 feet. It carries
cryogenic liquid hydrogen and liquid oxygen that feed the 4 RS-25 engines for the SLS.
Two solid rocket boosters add to the configuration. Orion is the safest, most advanced spacecraft
ever built. It is flexible and capable enough to take humans to a variety of destinations
including landing on an asteroid, and into interplanetary space.
After the December 2014 test flight, an unmanned Orion may circle the Moon by 2017 and the
first manned mission by 2021. Landing on an asteroid could take place during the late
2020s and a landing on Mars by the 2030s. If humans can't make it to near-Earth objects,
they can't make it to Mars so landing on an asteroid would be the next step necessary
toward a human landing on Mars. The Orion spacecraft is capable of carrying
astronauts on diverse expeditions beyond Earth's orbit, ushering in a new era a human space
exploration.
