Research and Development at NASA
Space Operations
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From
left, STS-114 astronauts Stephen Robinson,
James Kelly, Andrew Thomas, Wendy Lawrence,
Charles Camarda, Eileen Collins, and Soichi
Noguchi. |
NASA’s Space Operations Mission Directorate provides
many critical enabling capabilities that make possible
much of NASA’s science, research, and exploration
achievements. It does
this through the three themes of the Space Shuttle
Program, the International Space Station (ISS), and
Flight Support:
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On
July 26, 2005, Space Shuttle Discovery launched
into a clear blue sky on the historic Return
to Flight mission, STS-114. |
The Space Shuttle Program
builds on the Shuttle’s
primacy as the world’s most versatile launch system.
T
he Space Shuttle, first launched in 1981, returned
to flight in 2005, with Discovery carrying the
STS-114 crew to the ISS.
- The ISS establishes
a permanent human presence in Earth orbit. It also
provides a long-duration, habitable laboratory for
science and research activities investigating the
limits of human performance, expanding human experience
in living and working in space, and enabling the
commercial development
of space.
- Flight
Support consists of Launch Services, Space Communications,
and Rocket Propulsion Testing. These “enabling” services
are critical for conducting space exploration, as
well as aeronautical, materials science, biological,
and physical research.
Humans in space are the primary focus of this directorate.
Space is still the new frontier, and astronauts are
the pioneers of that frontier. The directorate explains,
explores, and chronicles the space projects humans
are involved in now and will be involved in, come
the future.
Space Shuttle: Return to Flight
Space Shuttle Discovery launched from Kennedy Space
Center on July 26, 2005, ending a 2.5-year wait for
the historic Return to Flight mission. STS-114 included
breathtaking in-orbit maneuvers, tests of new equipment
and procedures, a first-of-its-kind spacewalking
repair task, and telephone calls from two world
leaders.
|
Space
Shuttle Discovery is docked to the International
Space Station’s Destiny laboratory, with the
Earth’s horizon in the background. |
Discovery touched down on August 9 at Edwards Air Force
Base, California, following a successful reentry. The
orbiter returned to Kennedy on August 21, atop a modified
Boeing 747 called the Shuttle Carrier Aircraft. Discovery
then entered the Orbiter Processing Facility, where
it will be readied for mission STS-121.
During STS-114, NASA accomplished a variety of goals
while also learning some important lessons. At liftoff,
a large piece of insulating foam broke off the External
Tank. Now, NASA engineers are working to determine
what caused this and how to prevent it from happening
in the future.
Using the new Orbiter Boom Sensor System, Discovery
crewmembers took an unprecedented up-close look at
the orbiter’s Thermal Protection System. This collection
of new data was expanded on flight day 3, when Commander
Eileen Collins guided Discovery through the first-ever
“rendezvous pitch maneuver” as the orbiter approached
the ISS for docking.
The slow-motion backflip allowed Space Station crewmembers
John Phillips and Sergei Krikalev to snap high-resolution
photographs for mission managers to use to ensure Discovery
was in good shape to come home.
|
Stephen
Robinson is attached to a foot restraint on
the International Space Station’s Canadarm2.
This robotic extension guided Robinson to the
underside of Discovery, where he removed two
pieces of ceramic fabric, known as “gap fillers,”
that were protruding from heat-shielding tiles. |
During the first of three spacewalks, Mission Specialists
Stephen Robinson and Soichi Noguchi tested new repair
techniques for the outer skin of the Space Shuttle’s
heat shield and installed equipment outside the ISS.
They also repaired a control moment gyroscope. Two
days later, Robinson and Noguchi again ventured out
into the vacuum of space to replace a different, failed
control moment gyroscope, putting all four of the Station’s
gyroscopes back into service.
When two thermal protection tile gap-fillers
were spotted jutting out of Discovery’s underside,
astronauts and other experts on the ground devised
a plan to ensure that the protrusions would not cause
higher-than-normal temperatures on the Space Shuttle
during atmospheric reentry.
Ground controllers sent up plans to the Shuttle-Station
complex for Robinson to ride the Space Station’s robotic
arm beneath the Shuttle and, with surgical precision,
pluck out the gap-fillers.
|
A close-up view of
Discovery’s underside is featured in this image
photographed by Robinson—whose shadow is visible
on the thermal protection tiles—during the mission’s
third session of extravehicular activities. |
Work on the Shuttle underbelly had never been tried
before, but with Mission Specialist Wendy Lawrence
and Pilot Jim Kelly operating the robotic arms, Mission
Specialist Andy Thomas coordinating, and fellow spacewalker
Noguchi keeping watch, Robinson delicately completed
the extraction during the third and final spacewalk.
“Okay, that came out very easily,” Robinson said, after
carefully removing one of the fillers. “It looks like
this big patient is cured.”
The crew received phone calls from U.S. President
George W. Bush and Japanese Prime Minister Junichiro
Koizumi, who offered congratulations and appreciation
for the astronauts’ hard work.
Together, both the Discovery and ISS crews paid tribute
to the astronauts of Columbia, as well as others who
gave their lives for space exploration.
With the mission drawing to a close, the Multi-Purpose
Logistics Module, Raffaello, was removed from the ISS
and reinstalled in Discovery’s payload bay. Raffaello
arrived with more than 12,000 pounds of equipment and
supplies and carried about 7,000 pounds of Station
material on the trip back to Earth. After 9 days of
cooperative work, Discovery undocked from the ISS.
|
The Sun rises on Discovery
as it rests on the runway at Edwards Air Force
Base, California, after a safe landing August
9, 2005, to complete the STS-114 mission. |
The STS-114 crew was given an extra day in orbit on
August 8, when the first attempt to land at Kennedy
was foiled by uncooperative weather. Even though cloudy
skies reappeared at the Shuttle’s home port the next
morning, NASA was ready with a backup plan: a landing
at Edwards Air Force Base in the high desert of California,
where the weather was perfect.
Capsule Communicator Ken Ham congratulated the returning
crew on a spectacular test flight. “Stevie Ray, Soichi,
Andy, Vegas, Charlie, Wendy, and Eileen—welcome home,
friends.”
Those words, Collins said, were great to hear. “We’re
happy to be back, and we congratulate the whole team
for a job well done.”
International Space Station: Sustaining a Human Presence
in Space
While awaiting Discovery’s arrival, Expedition 11 NASA
Science Officer John Phillips and Commander Sergei
Krikalev conducted the first of their three renal stone
experiment sessions aboard the ISS. The renal stone
experiment investigates whether potassium citrate,
a proven Earth-based therapy used to minimize renal
(kidney) stone development, can be effective as a countermeasure
to reduce the risk of kidney stone formation for crewmembers
in space. Astronauts are at an increased risk of developing
kidney stones, because urinary calcium levels are typically
much higher in space.
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The International Space
Station was photographed from Space Shuttle Discovery
after the two spacecraft undocked. |
The renal stone investigation was designed as a double-blind
study. The crewmembers do not know whether they are
taking the potassium citrate or a placebo. Further,
the principal investigator who interprets the data
does not know in advance which crewmembers have taken
the potassium citrate or which have taken the placebo.
The principal investigator is studying the urine chemistry
of the samples to determine each individual’s risk
of renal stone formation. If the investigator’s hypothesis
is correct, the crewmembers identified as having a
lower renal stone formation risk will be those who
had taken the potassium citrate pills in-flight as
a countermeasure.
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During their initial session, Phillips and Krikalev
performed a urine collection over the course of 24
hours and logged everything they ate and drank for
48 hours.
This experiment is crucial to long-duration missions,
since kidney stones can incapacitate a crewmember,
and, in the worse case, threaten life if there is no
way to get the astronaut back to Earth quickly.
In a previous ISS research effort, Expedition 10 Commander
and NASA Science Officer Leroy Chiao and Flight Engineer
Salizhan Sharipov conducted an experiment to shed more
light on what is currently known about microgravity’s
effects on human muscle and bone.
In carrying out the ADvanced Ultrasound in Microgravity
(ADUM) experiment, Chiao and Sharipov performed ultrasound
bone scans on each other by taking turns as operator
and subject. The bone scans were taken of the shoulder,
elbow, knee, and ankle, monitored remotely from the
ground, and videotaped and photographed for downlink
and analysis.
Since there is no room for a fully functioning staff
of doctors aboard the ISS, nor is it feasible for
a crewmember to return to Earth for a quick medical
checkup, this experiment could lead to efficient
diagnosing of medical problems with minimal use of
onboard resources. Ability of crewmembers to use
an ultrasound machine with remote instruction—sending
information to the ground for analysis—can assist
in timely treatment, as well as avert unnecessary
evacuation. Crewmembers as far away as Mars could
eventually be remotely examined by doctors on Earth
using a modification of this technology. This type
of capability is essential for long-term space exploration.
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The Expedition 10 crewmembers also conducted a session
with the Miscible Fluids in Microgravity experiment.
Fluids do not behave the same on Earth as in the microgravity
environment inside the orbiting Space Station. This
experiment studies how miscible fluids, or those that
completely dissolve, interact without the interference
of gravity.
The test involved Chiao pulling tinted water from a
syringe through a drinking straw and into another syringe
containing a mixture of honey and water. The way the
fluid interacted was videotaped and photographed for
observation. This research could help scientists improve
the way plastics and other polymers are produced on
Earth and in space.
NASA’s Payload Operations team at Marshall Space Flight
Center is coordinating the aforementioned ISS science
activities.
Flight Support: Launch Services
|
Many of NASA’s most
famous missions—from those observing Earth, such
as EOS, Aura, and Landsat, to interplanetary
and deep space missions like the Mars Exploration
Rover and Deep Space 1—are launched on expendable
launch vehicles. |
Many of NASA’s most famous missions are launched on
expendable launch vehicles (ELVs). These missions are
unpiloted and can accommodate all types of orbit inclinations
and altitudes/attitudes.
In 1997, Kennedy was assigned lead center program responsibility
for NASA’s acquisition and management of ELV launch
services. Its ELV Program Office provides a single
focal point for these services, while affording NASA
the benefits of consolidated and streamlined technical
and administrative functions. The program, with its
vision statement, “Global Leadership in Launch Service
Excellence,” provides launch services for NASA, NASA-sponsored
payloads, and other government payloads.
Primary launch sites are Cape Canaveral Air Force Station,
Florida, and Vandenberg Air Force Base, California;
other launch locations are NASA’s Wallops Island, Virginia;
Kodiak Island, Alaska; and Kwajalein Atoll, in the
Republic of the Marshall Islands, in the North Pacific.
Since 1990, NASA has been purchasing ELV launch services
directly from commercial providers, whenever possible,
for its scientific and applications missions that are
not assigned to fly on the Space Shuttle. Because ELVs
can accommodate all types of orbit inclinations and
altitudes/attitudes, they are ideal for launching Earth-orbit
and interplanetary missions.
Kennedy is also responsible for NASA oversight of launch
operations and countdown management. A motivated and
skillful team is in place to meet the mission of the
ELV program: “To provide launch service excellence,
expertise, and leadership to ensure mission success
for every customer.”
In late-May 2005, NASA successfully launched a new
environmental satellite for the National Oceanic and
Atmospheric Administration (NOAA), using a Boeing Delta
II 7320-10 ELV. The satellite, NOAA-18, aims to improve
weather forecasting and monitor environmental events
around the world.
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NOAA-18 is the latest
polar-orbiting satellite developed by NASA for
the National Oceanic and Atmospheric Administration
(NOAA). NOAA-18 will collect information about
Earth’s atmosphere and environment to improve
weather prediction and climate research across
the globe. |
The NOAA-18 spacecraft lifted off from Vandenberg
Air Force Base, on the Delta II. Approximately 65
minutes later, the spacecraft separated from the
ELV second stage.
“The satellite is in orbit and all indications are
that we have a healthy spacecraft,” said Karen Halterman,
the NASA Polar-orbiting Operational Environmental
Satellites (POES) project manager, based at Goddard
Space Flight Center. “NASA is proud of our partnership
with NOAA in continuing this vital environmental
mission,” she added.
NOAA-18 will collect data about the Earth’s surface
and atmosphere. The data are input to NOAA’s long-range
climate and seasonal outlooks, including forecasts
for El Niño and La Niña. NOAA-18 is the fourth
in a series of five POES with instruments that
provide improved imaging and sounding capabilities.
NOAA-18 has instruments used in the International
Search and Rescue Satellite-Aided Tracking System,
called COSPAS-SARSAT, which was established in
1982. NOAA POES detect emergency beacon distress
signals and relay their location to ground stations,
so rescue can be dispatched. SARSAT is credited
with saving approximately 5,000 lives in the United
States and more than 18,000 worldwide.
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NOAA manages the POES program and establishes
requirements, provides all funding, and distributes
environmental satellite data for the United
States. Goddard procures and manages the development
and launch of the satellites for NOAA on a
cost-reimbursable basis.
Flight Support: Space Communications
Sophisticated signal-processing techniques and
simple proof-of-principle antenna arrays built
from
PVC pipe, aluminum foil, and copper wire could
revolutionize the way NASA obtains data from its
Earth-observing satellites.
If the adaptive array system being studied by NASA
and Georgia Institute of Technology (Georgia Tech)
researchers ultimately proves feasible, it could
make information from the Space Agency’s Earth-observing
satellites more widely and rapidly available. The
“off-the-shelf” technology has already demonstrated
that it can successfully receive one satellite
telemetry frequency.
“The dream would be to make these NASA information
services available to anybody sitting at a computer,
almost like video-on-demand,” explained Mary Ann
Ingram, a professor at Georgia Tech’s School of
Electrical and Computer Engineering. “Timely information
from Earth-observing satellites could be useful
in many ways, such as directing operations to fight
a forest fire,
for instance.”
|
Operation and Deployment
Experiments Simulator (ODES) engine testing at
White Sands Test Facility in New Mexico. |
Information from satellites such as Earth Observing-1
(EO-1) is now downlinked to various 11-meter dishes,
primarily in the Arctic Circle, where subzero temperatures
create maintenance and reliability issues for their
complex aiming mechanisms. Typically, satellites
such as EO-1 are in contact with these antenna
systems 5 to 8 times a day, for 10 minutes at a
time. The present antenna systems require resident
crews to operate and maintain them.
The NASA/Georgia Tech project envisions replacing
these antennas with a network of inexpensive antenna
arrays that would have no moving parts and use
sophisticated software—instead of careful aiming—to
gather data from the satellites. The network could
lower operational costs while improving access
to the information.
“When people use cell phones to make calls, there
are no moving parts on the antennas,” noted Dan
Mandl, mission director for NASA’s EO-1 program
at Goddard. “What I would like to do is build a
continuous cell-like network around the world that
would provide almost unlimited opportunities to
downlink data.”
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Mandl compared NASA’s existing downlink system
to old-fashioned pay phones located off expressway
exits. “If you witness an accident, you can open
your cell phone and call for assistance,” he said.
“But if you don’t have a cell phone, you have to
get off the highway at the next exit and hunt for
a pay phone. What we would like to do is give these
satellites the equivalent of cell phones to allow
anytime, anywhere contact.”
The proof-of-principle adaptive arrays being tested
by Ingram and her research team are built from
inexpensive components, including common PVC piping
and aluminum foil. Signals from the four antennas
are analyzed using a processing technique that
learns to improve its performance, by constructively
combining scattered and reflected versions of the
signal and by suppressing noise and interference.
This eliminates the need for costly front-end hardware
and precise aiming of the antenna arrays, and enables
flexibility in the location of the ground station.
“Instead of one big aperture from an 11-meter dish,
we’re going to use several smaller apertures and
connect them with digital signal processing,” Ingram
explained. “A smaller aperture has a wider beam,
so the tracking requirement won’t be as great.
They may pick up interference, especially in tracking
a satellite at a low-elevation angle, but because
we combine multiple apertures, we can null out
the interference.”
The arrays individually will not provide the same
data rate as NASA’s large structures, but having
more of them spread out around the world will compensate
for that. Network capacity studies show that two
ground stations, each with seven 0.75-meter dishes
or eight electronically steered antennas, could
equal the data capacity of NASA’s existing 11-meter
dish in Poker Flats, Alaska, at a significantly
lower cost.
And because an array does not depend on precisely
aiming a dish, each one could potentially communicate
with more than one satellite at a time. “What we’d
really like to have is a shared antenna resource,
in which software is used to separate out the signals,”
Mandl explained.
“As we get more satellites up in space, this will
become more important.”
In testing performed at Georgia Tech, researchers
were able to downlink EO-1 information in the S-band,
a frequency used for transmissions at low data
rates. They had to develop a special filter to
eliminate interference from terrestrial repeater
stations of popular satellite
radio services.
“We have demonstrated the lower rates in S-band,
and, during the upcoming year, we will work on
X-band for higher rates,” Mandl said. “Ultimately,
we would like to demonstrate Ka band, which is
in the 27-28 gigahertz range. You could potentially
get anywhere from 300 megabits to a gigabit of
data in that stream.”
To extend satellite reception time, researchers
are also examining several technical issues, such
as array-based synchronization and optimization
of the tilt angles of the planar apertures of the
electronically steered antennas. This optimization
could quadruple the download capacity for a ground
station with eight electronically steered antennas.
If successful, the adaptive array project would
give NASA more flexibility in design of future
high-data rate satellites that may generate terabits
of data on each orbit of the Earth. Reliably downlinking
that amount of information will require a new approach,
Mandl noted.
“If you are in the Arctic and the motor moving
your dish breaks down, it may take a few weeks
to fix it,” Mandl said. “If this could be done
with no moving parts, using techniques of digital
signal processing and software radio, one of the
most desirable features will be a high level of
reliability. That’s important for space applications
and locations where you can just put equipment
out there and not require an operator or maintenance
crew.”
Flight Support: Rocket Propulsion Testing
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NASA scientists began
generating plasma energy in a 9-inch vacuum chamber
in NASA’s Propulsion Research Laboratory at the
Marshall Space Flight Center. In partnership
with researchers at the University of Texas at
Austin, Johnson Space Center, and the University
of Alabama, Marshall scientists are developing
innovative magnetic nozzles capable of properly
channeling superheated plasma without nozzle
deterioration, causing the plasma to accelerate
to velocities far faster than those of conventional
chemical propulsion systems. Such component technology
could support development of next-generation,
plasma-propelled spacecraft capable of safely
and quickly carrying robotic or human exploration
missions deep into the solar system. |
On July 6, 1962, NASA selected the White Sands
Test Facility (WSTF) as the site for Johnson Space
Center’s Propulsion Systems Development Facility.
This site was chosen for its isolated location
and topography, which minimized the inherent hazards
of aerospace propulsion testing to the general
population. WSTF began testing rocket engines in
1964. More than 310 engines have been tested, for
a total number of firings exceeding 2.1 million.
WSTF’s 300 and 400 Propulsion Test Areas were originally
constructed to test the engines for the Apollo
Command and Service Modules and the Lunar Module.
In September 1964, the first firing test of the
main rocket engine for the Apollo Command and Service
Modules was conducted. The Lunar Module descent
engine, which allowed the craft to land softly
on the Moon, and the ascent engine, which was used
to launch the craft from the lunar surface, were
certified for flight after hundreds of firings
in the 400 Area. The reaction control system, which
consisted of the small thrusters that control the
spacecraft attitude, was also certified for flight
at WSTF.
Today, six test stands provide vacuum test capability,
and three test stands provide ambient testing,
5,000 feet above sea-level, for the Space Shuttle,
the ISS, and for other government agency tests.
Stennis Space Center is NASA’s primary center
for testing and proving flight-worthy rocket
propulsion systems for the Space Shuttle and
future generations of space vehicles. Having
conducted engine testing for 4 decades, Stennis
is NASA’s program manager for rocket propulsion
testing with total responsibility for conducting
and managing all NASA propulsion test programs.
Exploration Systems
The Exploration Systems Mission Directorate is
responsible for creating new capabilities and supporting
technologies that enable sustained and affordable
human and robotic exploration. This mission directorate
is also responsible for effective utilization of
ISS facilities and other platforms for research
that support long-duration human exploration.
Plasma Energy Technology to Propel
Deep-Space Missions
NASA scientists have begun generating plasma
energy in a 9-inch vacuum chamber in NASA’s
Propulsion Research Laboratory at Marshall.
In partnership with researchers at the University
of Texas at Austin, Johnson, and the University
of Alabama, in Huntsville, Marshall scientists
are developing innovative magnetic nozzles
capable of properly channeling superheated
plasma without nozzle deterioration, causing
the plasma to reach very high velocities.
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Susan Young Lee, lead
hardware engineer, and Eric Park, computer scientist,
working on a K-10 Rover in one of Ames Research
Center’s robotics laboratories. |
Such component technology could support development of next-generation,
plasma-propelled spacecraft capable of safely and quickly carrying robotic
or human exploration missions deep into the solar system. This could
dramatically reduce travel times to Earth’s neighboring planets and extend
the capabilities of future space exploration missions.
The new research project has two objectives: development of an innovative
magnetic nozzle design capable of directing the flow of plasma, and determining
how to efficiently eject the plasma from the nozzle to produce the greatest
propulsive thrust.
Plasma is a highly conductive medium formed when a gas is heated and
ionized—the process in which the gas’s neutral atoms shed electrons and
acquire a positive charge. When properly channeled through a magnetic
nozzle, plasma can be accelerated to velocities dramatically faster than
those of conventional chemical propulsion systems.
Propellant in a plasma state can be accelerated with the use of electromagnetic
energy sources to increase the propulsion system’s specific impulse—the
equivalent of a car’s gas mileage. Such a nozzle, magnetically insulated
against the superheated plasma flow, would enable plasma acceleration
at temperatures far beyond those conventional materials can endure.
The second challenge is rooted in the physics of magnetized plasma flow.
A plasma propulsion system requires magnetic coils to generate and channel
the plasma. These coils produce closed magnetic field lines—circular
loops of magnetic energy that form around the power source—and prevent
the plasma from detaching and leaving the spacecraft.
The research consortium seeks to test mechanisms that allow the plasma
stream—already properly shaped by the magnetic nozzle—to break away from
the spacecraft, generating maximum thrust by dispersing the plasma at
exactly the right moment following expulsion from the rear of the spacecraft.
Eventually, NASA hopes to adapt this research to develop a new class
of rockets incorporating magnetic nozzles and plasma propulsion systems.
NASA Develops Robot With Human Traits
NASA researchers envision futuristic robots that “act” like people, enabling
these mechanical helpers to work more efficiently with astronauts. Human-robot
cooperation, in turn, will enable exploration of the Moon and Mars, and
even large-scale construction in extraterrestrial places. Because human
crews will be limited to small teams, astronauts will need robot helpers
to do much of each team’s work.
Though remotely controlled machines and robots that work entirely on
their own are valid goals, a research team at Ames Research Center plans
to focus on robots that are partly controlled by people and operate independently
the rest of the time.
|
An eight-legged Scorpion
robot prototype test under development at Ames
Research Center is just one example
of the innovative robotics work being done at
that center. |
There are three main areas under development. One is called collaborative
control, during which the human being and the robot will speak to one
another and work as partners. The second area is building robots with
reasoning mechanisms that work similarly to human reasoning. Thirdly,
the researchers will conduct field tests of people and robots working
together.
Many experiments will occur in a special, indoor laboratory under construction
at Ames, featuring a control room with a window looking out on robots
working in a large area that will simulate the surface of a moon or planet.
The control room will imitate a human habitat on the Moon or Mars.
The robots will help assemble buildings, test equipment, weld structures,
and dig with small tools. Human-robot teams will use a checklist and
a plan to guide their joint efforts. The robot development work will
focus on specific tasks essential for basic exploration mission operations
including: shelter and work hangar construction, piping assembly and
inspection, pressure vessel construction, habitat inspection, resource
collection, and transport.
Scientists say human-robot cooperation will result in a better outcome
than human- or robot-only teams could accomplish. To make human-machine
teaming a reality, a NASA multi-pronged effort is underway to develop
robot intelligence. Similar to human thinking, it is designed to improve
the mechanical workings of robots and to standardize human-robot communications.
Robots Will Search for Lunar Water
Deposits
The Vision for Space Exploration spells out a long-term strategy of returning
to the Moon as a step towards sending humans to Mars and beyond. The
Moon, so nearby and accessible, is a great place to try out new technologies
critical to living on alien worlds before venturing across the solar
system.
Whether a Moon base will turn out to be feasible hinges largely on
the question of water. Colonists need water to drink. They need water
to grow plants. They can also break water apart to make air (oxygen)
and rocket fuel (oxygen + hydrogen). Furthermore, water is surprisingly
effective at blocking space radiation. Surrounding the base with a
few feet of water would help protect explorers from solar flares and
cosmic rays. The problem is that water is dense and heavy. Carrying
large amounts of it from Earth to the Moon would be expensive. Settling
the Moon would be so much easier if water were already there.
Astronomers believe that comets and asteroids hitting the Moon eons
ago left water behind. (Scientists believe that Earth may have received
its water in the same way.) Water on the Moon does not last long. It
evaporates in sunlight and drifts off into space. Only in the shadows
of deep, cold craters could an explorer expect to find any, frozen
and hidden. Indeed, there may be deposits of ice in such places.
In the 1990s, two spacecraft, Lunar Prospector and Clementine, found
tantalizing signs of ice in shadowed craters near the Moon’s poles—perhaps
as much as a cubic kilometer. The data were not conclusive, though.
To find out if lunar ice is truly there, NASA plans to send a robotic
scout. The Lunar Reconnaissance Orbiter, or “LRO” for short, is scheduled
to launch in 2008 and to orbit the Moon for a year or more. Carrying
six different scientific instruments, LRO will map the lunar environment
in greater detail than ever before. LRO’s instruments will do many
things: they will map and photograph the Moon in detail, sample its
radiation environment, and hunt for water.
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The spacecraft’s Lyman-Alpha Mapping Project (LAMP) will attempt to
peer into the darkness of permanently shadowed craters at the Moon’s
poles, looking for signs of ice hiding there. By looking for the dim
glow of reflected starlight, LAMP senses a special range of ultraviolet
light wavelengths. Not only is starlight relatively bright in this
range, but also the hydrogen gas that permeates the universe radiates
in this range as well. To LAMP’s sensor, space itself is literally
aglow in all directions. This ambient lighting may be enough to see
what lies in the inky blackness of these craters.
The spacecraft is also equipped with a laser that can shine pulses
of light into dark craters. The main purpose of the instrument, called
the Lunar Orbiter Laser Altimeter (LOLA), is to produce a highly accurate
contour map of the entire Moon. As a bonus, it will also measure the
brightness of each laser reflection. If the soil contains ice crystals,
as little as 4 percent, the returning pulse would be noticeably brighter.
One of LRO’s instruments, Diviner, will map the temperature of the
Moon’s surface. Scientists can use these measurements to search for
places where ice could exist. Even in the permanent shadows of polar
craters, temperatures must be very low for ice to resist evaporation.
Thus, Diviner will provide a “reality check” for LRO’s other ice-sensitive
instruments, identifying areas where positive signs of ice would not
make any sense, because the temperature is simply too high.
Not far from some permanently shadowed craters are mountainous regions
in permanent sunlight, known romantically as “peaks of eternal sunshine.”
Conceivably, a Moon base could be placed on one of those peaks, providing
astronauts with constant solar power—not far from crater valleys below,
rich in ice and ready to be mined.
NASA’s Desert ‘Rats’ Test New Gear
|
The Remote Field Demonstration
Test Site serves as sort of a dry run of a dry
run. Researchers use the rugged terrain and varied
climate to test prototype space suits and innovative
equipment. |
Arizona’s high desert is not quite as tough on equipment as the Moon
or Mars, but few places on Earth can give prototype space suits, rovers,
and science gear a better workout.
A NASA-led team headed for sites near Flagstaff, Arizona, in September,
to test innovative equipment. Engineers and scientists led the Desert
Research and Technology Studies (RATS) team from Johnson and Glenn
Research Center. The team included members from NASA centers, universities,
and private industry. Their efforts may help America pursue the Vision
for Space Exploration to return to the Moon and travel beyond.
The sand, grit, dust, rough terrain, and extreme temperature swings
of the desert are attractive, simulating some of the conditions that
may be encountered on the Moon or Mars. Crews wearing prototype-advanced
space suits used and evaluated the new equipment for 2 weeks.
“For field testing, the desert may be the closest place on Earth
to Mars, and it provides valuable hands-on experience,” said Joe
Kosmo, Johnson’s senior project engineer for the experiments. “This
work will focus on the human and robotic interaction we’ll need for
future lunar and planetary exploration, and it will let us evaluate
new developments in engineering, science, and operations,” he added.
Engineers in the Exploration Planning and Operations Center at Johnson
provided mission control-type monitoring of the field tests.
The test equipment included:
- New space suit helmet-mounted speakers
and microphones for communications.
- A “field assistant”
electric tractor that follows test subjects in
space suits, and is guided by space suit-mounted
controls.
- A wireless network, for use on other
planets, that can relay data and messages among
spacewalkers, robots, and rovers as they explore
the surface.
- A two-wheeled chariot that is pulled
by the electric tractor to carry astronauts.
- “Matilda,”
an autonomous robotic support vehicle that can
retrieve geologic samples.
- Analytical equipment mounted
on two mobile geology laboratories.
Science
NASA’s Science Mission Directorate carries out the scientific exploration
of the Earth, Moon, Mars, and beyond; charts the best route of discovery;
and reaps the benefits of Earth and space exploration for society.
By combining Earth and space science, NASA is best able to establish
an understanding of the Earth, other planets, and their evolution,
bringing the lessons of our study of Earth to the exploration of
the solar system and assuring the discoveries made here will enhance
our work there.
Deep Impact Mission
|
Artist Pat Rawlings
illustrates the moment of impact and the forming
of the crater during the Deep Impact Mission. |
Comets are time capsules that hold clues about the formation and
evolution of the solar system. They are composed of ice, gas, and
dust, primitive debris from the solar system’s distant and coldest
regions that formed 4.5 billion years ago. Deep Impact, a NASA Discovery
Program mission, is the first to probe beneath the surface of a comet
and reveal the secrets of its interior.
At the culmination of the 6-year mission, on July 3, 2005, a
370-kilogram impactor was released from the Deep Impact spacecraft.
The spacecraft watched from a safe distance while the impactor
collided with comet Tempel 1 at 6.3 miles per second (10 kilometers
per second) or 23,000 miles per hour (37,000 kilometers per hour),
on July 4. The impact created a magnificent flash of light as
an immense cloud of fine powdery material was ejected and subsequently
captured in 4,500 images from the spacecraft’s cameras.
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Scientists continue to analyze the gigabytes of
data collected from the 4th of July fireworks in
deep space. It is estimated that the crater formed
from the impact is between 165 and 820 feet (50
and 250 meters) wide. Analyzed data will be combined
with that of other NASA and international comet
missions. Results from these missions will lead
to a better understanding of both the solar system’s
formation and implications of comets colliding with planetary surfaces.
Mars Exploration Rover Mission
We’re going to overtime—for the third time.
|
Full frame experiment
data record acquired on Sol 494 of Spirit’s mission
to Gusev Crater, at approximately 16:37:46 Mars
local solar time. |
In April 2005,
NASA approved up to 18 more months of operations
for Spirit and Opportunity, the twin Mars rovers that have
already surprised engineers and scientists by continuing
active exploration for more than 20 months—well past their
3-month primary mission.
The rovers have proven their value with major
discoveries about ancient watery environments on Mars that
might have harbored life. Shortly after landing in January
2004, Opportunity found geological evidence of a shallow ancient
sea. More than a year later, Spirit found a new class of water-affected
rock. The Science Mission Directorate leadership decided to
extend the mission through September 2006 to take advantage
of having such capable resources still healthy and in excellent
position to continue the Mars adventures.
With the rovers already performing well beyond their original
design lifetimes, there is a distinct possibility that, at
any time, a part could wear out and therefore disable the robotic
explorers. Both rovers, however, show no signs of letting up,
despite traveling through dust devils and sand traps. Through
August 2005, Spirit and Opportunity have explored over 6.5
miles (10.5 kilometers) of Martian terrain.
Cassini-Huygens Mission
The Cassini spacecraft is embarking on a new mission phase
that will give it a ringside seat at Saturn—literally. After
concentrating on flybys of Saturn’s moons since arriving last
year, Cassini began a 5-month study of the stately planet’s
magnificent rings in April with 12 instruments onboard. Knowing
how the rings form and how long they have been there are central
questions for the Cassini-Huygens mission.
|
In this true color
view, Mimas, one of the innermost moons of Saturn,
drifts along in its orbit, against the azure
backdrop of Saturn’s northern latitudes. |
In a spectacular kickoff to its first season of prime ring
viewing, Cassini has confirmed earlier suspicions of an unseen
moon hidden in a gap in Saturn’s outer “A” ring, known as the
Keeler Gap.
The moon, provisionally called S/2005 S1, was first seen
in a time-lapse sequence of images taken on May 1, 2005,
as Cassini began its climb to higher inclinations in orbit
around Saturn. A day later, an even closer view was obtained,
which has allowed measurement of its size
and brightness.
S/2005 S1 is the second-known moon to exist within Saturn’s
rings. The other is Pan, which orbits in the Encke Gap of the
“A” ring. Imaging scientists had predicted the new moon’s presence
and its orbital distance from Saturn after a July 2004 sighting
of a set of peculiar spiky and wispy features in the Keeler
Gap’s outer edge. The similarities of the Keeler Gap features
to those noted in Saturn’s “F” ring and the Encke Gap led imaging
scientists to conclude that a small body, a few kilometers
across, was lurking in the center of the Keeler Gap, awaiting
discovery.
NASA scientists have also concluded that another Saturn moon,
Phoebe, is an interloper to the Saturn system from the deep
outer solar system.
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When Cassini flew by Phoebe on its way to Saturn on June 11,
2004, little was known about the battered, crater-filled moon
at that time. During the encounter, scientists got the first
detailed look at Phoebe, which allowed them to determine its
makeup and mass. As new information unfolded, scientists were
able to determine that Phoebe has an outer solar system origin,
akin to Pluto and other members of the Kuiper Belt.
|
Specially calculated
Cassini orbits place Earth and Cassini on opposite
sides of Saturn’s rings, a geometry known as
occultation. Cassini conducted the first radio
occultation observation of Saturn’s rings on
May 3, 2005. |
“Phoebe was left behind from the solar nebula, the cloud of
interstellar gas and dust from which the planets formed,” said
Dr. Torrence Johnson, a Cassini imaging team member at the
Jet Propulsion Laboratory (JPL). “It did not form at Saturn.
It was captured by Saturn’s gravitational field and has been
waiting eons for Cassini to come along.”
Phoebe has a density consistent with that of the only Kuiper
Belt objects for which densities are known. Phoebe’s mass,
combined with an accurate volume estimate from images, yields
a density of about 100 pounds per cubic foot (1.6 grams per
cubic centimeter), much lighter than most rocks, but heavier
than pure ice, which is about 58 pounds per cubic foot (0.93
grams per cubic centimeter). This suggests a composition of
ice and rock similar to that of Pluto, and Neptune’s moon,
Triton. Whether the dark material on other moons of Saturn
is the same primordial material as on Phoebe remains to be
seen.
Meanwhile, new observations have been made about Saturn’s largest
moon, Titan. Huygens, a European Space Agency probe with six
instruments onboard, landed safely on Titan on January 14,
2005, recording hundreds of megabytes of data during its descent
through the atmosphere and while on the surface. Titan is the
only known moon in our solar system that has a thick atmosphere.
Huygens revealed that the thick atmosphere of this giant moon
is rich in organic compounds, whose chemistry may be similar
to that of primordial Earth several billion years ago.
“Titan is not just a dot in the sky; these new observations
show that Titan is a rich, complex world, much like the Earth
in some ways,” said Dr. Michael Flasar, the Composite Infrared
Spectrometer (CIRS) instrument principal investigator at Goddard.
In all, there will be 45 flybys of Titan during the Cassini-Huygens
nominal mission, giving scientists more information to unravel
the mysteries of its thick atmosphere and other Earth-like
processes, such as tectonics, erosion, winds, and perhaps volcanism,
which may have shaped Titan’s surface.
Swift Mission
|
The Boeing Delta II
launch vehicle for NASA’s Swift spacecraft is
silhouetted against a rosy sky at sunrise, waiting
for liftoff. |
Scientists using the Swift satellite—launched on November 20,
2004—and several ground-based telescopes have detected the
most distant explosion yet, a gamma-ray burst from the edge
of the visible universe.
This powerful burst was detected September 4, 2005. It marks
the death of a massive star and the birth of a black hole.
It comes from an era soon after stars and galaxies first formed,
about 500 million to 1 billion years after the Big Bang. Gamma-ray
bursts are the most powerful explosions the universe has seen
since the Big Bang. They occur approximately once per day and
are brief, but intense, flashes of gamma radiation.
“We designed Swift to look for faint bursts coming from the
edge of the universe,” said Swift principal investigator, Dr.
Neil Gehrels, of Goddard. “Now we’ve got one, and it’s fascinating.
For the first time, we can learn about individual stars from
near the beginning of time. There are surely many more out
there,” he added.
The Swift satellite is designed specifically for gamma-ray
burst science. Its three instruments work together to observe
gamma-ray bursts and afterglows in the gamma-ray, X-ray, and
optical wavebands. The Burst Alert Telescope (BAT) monitors
the entire sky to catch a gamma-ray burst and calculate an
initial position. Within seconds of detecting a burst, Swift
will relay the burst’s location to ground stations, allowing
both ground-based and space-based telescopes around the world
the opportunity to observe the burst’s afterglow. Armed with
the position, the Swift spacecraft autonomously points two
other onboard telescopes within their field-of-view, within
90 seconds. All three telescopes watch the gamma-ray burst
and afterglow unfold. During Swift’s 2-year nominal mission,
scientists should have data for approximately 200 gamma-ray
bursts to determine their origin and study activities of the
early universe.
Detecting Coastal Pollution
Back on Earth, a NASA-funded study of marine pollution in southern
California concluded that space-based synthetic aperture radar
can be a vital observational tool for assessing and monitoring
ocean hazards in urbanized coastal regions.
|
An artist’s rendering of the Swift spacecraft
with a gamma-ray burst in the background. |
“Clean beaches and coastal waters are integral to southern
California’s economy and lifestyle,” said
Dr. Paul DiGiacomo, a JPL oceanographer and lead author
of a study recently published in the Marine Pollution Bulletin.
“Using southern California as a model system, we’ve shown
existing high-resolution, space-based radar systems can
be used to effectively detect and assess marine pollution
hazards. This is an invaluable tool for water quality managers
to better protect public health and coastal resources,”
he added.
DiGiacomo and colleagues from JPL; the University
of California, Santa Barbara; and the University of Southern
California, Los Angeles, examined satellite radar imagery of
the state’s southern coastal waters. The area is adjacent to
20 million people, nearly 25 percent of the U.S. coastal population.
“The key to evaluating and managing pollution hazards in urban
coastal regions is accurate, timely data,” DiGiacomo said.
“Since such hazards are usually localized, dynamic, and episodic,
they’re hard to assess using oceanographic field sampling.
Space-based imaging radar works day and night, regardless of
clouds, detecting pollution deposits on the sea surface. Combined
with field surveys and other observations, including shore-based
radar data, it greatly improves our ability to detect and monitor
such hazards.”
The study described three major pollutant sources for southern
California: storm water runoff, wastewater discharge, and natural
hydrocarbon seepage.
“During late fall to early spring, storms contribute more than
95 percent of the region’s annual runoff volume and pollutant
load,” said JPL co-author Ben Holt. “Californians are accustomed
to warnings to stay out of the ocean during and after storms.
Even small storms can impact water quality. Radar data can
be especially useful for monitoring this episodic seasonal
runoff.”
DiGiacomo noted that a regional southern California marine
water quality-monitoring survey is under way, involving JPL
and more than 60 other organizations, including the Southern
California Coastal Water Research Project. Its goal is to characterize
the distribution and ecological effects of storm water runoff
in the region. Space radar and other satellite sensor data
are being combined, including NASA’s Moderate Resolution Imaging
Spectroradiometers (MODIS). The sensors provide frequent observations,
subject to clouds, of ocean color that can be used to detect
regional storm water runoff and complement the finer resolution,
but less frequent, radar imagery.
The second largest source of the area’s pollution
is wastewater discharge. Publicly owned treatment works discharge
daily more than 1 billion gallons of treated wastewater into
southern California’s coastal waters.
Even though it is discharged deep offshore, submerged plumes
occasionally reach the surface and can contaminate local shorelines.
Natural hydrocarbon seeps are another local pollution hazard.
Underwater seeps in the Santa Barbara Channel and Santa Monica
Bay have deposited tar over area beaches. Space-imaging radar
can track seepage on the ocean surface, as well as human-caused
oil spills, which are often affected by ocean circulation patterns
that make other tracking techniques difficult.
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Further research is necessary to determine the composition
of pollution hazards detected by radar. “From imaging radar,
we know where the runoff is, but not necessarily which parts
of it are harmful,” Holt said. “If connections can be established,
imaging radar may be able to help predict the most harmful
parts of the runoff.”
While the researchers said environmental conditions such as
wind and waves can limit the ability of space radar to detect
ocean pollution, they stressed the only major limitation of
the technique is infrequent coverage. “Toward the goal of a
comprehensive coastal ocean observing system, development of
future radar missions with more frequent coverage is a high
priority,” DiGiacomo noted.
Detecting Airborne Pollution
NASA scientists have discovered that pollution could catch
an airborne “express train,” or wind current, from Asia all
the way to the southern Atlantic Ocean.
|
The red arrows
on this globe trace the fast track of ozone pollution
from Asia as it contributes to the highest ozone
episodes found in the South Atlantic. |
Scientists believe that, during certain seasons, as much as
half of the ozone pollution above the Atlantic Ocean may be
speeding down a track of air from the Indian Ocean. As it rolls
along, it picks up more smog from air peppered by thunderstorms
that bring the pollution up from the Earth’s surface.
Bob Chatfield, a scientist at Ames, said, “Man-made pollution
from Asia can flow southward, get caught up into clouds, and
then move steadily and rapidly westward across Africa and the
Atlantic, reaching as far as Brazil.”
Chatfield and Anne Thompson, a scientist at Goddard, used data
from two satellites and a series of balloon-borne sensors to
spot situations when near-surface smog could catch the wind
current westward several times annually from January to April.
During those periods of exceptionally high ozone in the South
Atlantic, especially during late winter, researchers noticed
Indian Ocean pollution follows a similar westward route, wafted
by winds in the upper air. They found the pollution eventually
piles up in the South Atlantic. “We’ve always had some difficulty
explaining all that ozone,” Thompson admitted.
“Seasonal episodes of unusually high ozone levels over the
South Atlantic seem to begin with pollution sources thousands
of miles away in southern Asia,” Chatfield said. Winds are
known to transport ozone and pollutants thousands of miles
away from their original sources.
Clearly defined, individual layers of ozone in the tropical
South Atlantic were traced to lightning sources over nearby
continents. In addition to ozone peaks associated with lightning,
high levels of ozone pollution came from those spots in the
Sahel area of North Africa where vegetation burned. However,
even outside these areas, there was extra ozone pollution brought
by the Asian “express train.”
The scientists pinpointed these areas using the joint NASA-Japan
Tropical Rainfall Measuring Mission (TRMM) satellite to see
fires and lightning strikes, both of which promote ozone in
the lower atmosphere. Researchers also identified large areas
of ozone smog moving high over Africa using the Total Ozone
Mapping Spectrometer (TOMS) satellite instrument.
They further confirmed the movement of the smog by using sensors
on balloons in the Southern Hemisphere Additional Ozonesondes
(SHADOZ) network. A computer model helped track the ozone train
seen along the way by the SHADOZ balloon and satellite sensors.
The scientists recreated the movement of the ozone from the
Indian Ocean region to the southern Atlantic Ocean.
Going to ‘Extremes’
Hundreds of feet under the Alaskan tundra, Marshall astrobiologist
Dr. Richard Hoover ignored the eerie silence of the icy tunnel
around him, and even the bones of woolly mammoths and steppe
bison jutting from the jagged walls, frozen where they died
tens of thousands of years ago.
Forget the fossils.
Hoover was instead poring over pale blue and white patches
covering an ice wedge in the tunnel wall. It was a microbial
community of bacteria and fungi, growing in total darkness,
thriving at temperatures that have hovered below freezing for
thousands of years.
For Hoover and his research colleagues, proof of life is the
real find, especially in a subterranean tomb, sleeping under
ice from the Pleistocene Age. In this unlikely place, they
discovered a new life form, a never-before-seen bacterial species
they have dubbed Carnobacterium pleistocenium. It is roughly
32,000 years old—and it is still alive.
|
Dr. Elena Pikuta, a
scientist at the University of Alabama in Huntsville,
and Dr. Richard Hoover, a NASA astrobiologist,
lead a team of researchers who recently discovered
a new life form: an “extremophile” that lives
and thrives in conditions inhospitable to most
life on Earth. |
The bacterium—the first fully described, validated species
ever found alive in ancient ice—is one of NASA’s latest discoveries
of an “extremophile.” Extremophiles are hardy life forms that
exist and flourish in conditions hostile to most known organisms,
from the potentially toxic chemical levels of salt-choked lakes
and alkaline deserts to the extreme heat of deep-sea volcanoes
and hydrothermal vents. NASA and its partner organizations
study the potential for life in such extreme zones to help
understand the limitations of life on Earth and to prepare
robotic probes and, eventually, human explorers to search other
worlds for signs of life.
The search for extremophiles is a key element of the Vision
for Space Exploration, which aims to reveal unimaginable life
forms that could be thriving in conditions few Earth species
could tolerate.
“The existence of microorganisms in these harsh environments
suggests—but does not promise—that we might one day discover
similar life forms in the glaciers or permafrost of Mars, or
in the ice crust and oceans of Jupiter’s moon, Europa,” Hoover
noted.
There are approximately 7,000 validly described species of
bacteria, though far more are surmised to exist in nature.
The vast majority of bacteria are harmless to humans. Only
a very few—less than 1 percent of all known species—are dangerous,
and many, Hoover noted, are valuable to human life, aiding
us in numerous ways: aiding in the production of valuable proteins
and life-saving drugs; culturing wine, dairy products, and
other foods; and assisting in the biological extraction of
gold and other precious metals from ore wastes.
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Carnobacterium pleistocenium could
offer new breakthroughs in medicine, Hoover said. “The enzymes
and proteins it possesses, which give it the ability to spring
to life after such long periods of dormancy, might hold the
key to long-term cryogenic, or very low-temperature, storage
of living cells, tissues, and perhaps even complex life forms,”
he said.
Aeronautics Research
The Aeronautics Research Mission Directorate is committed to
developing tools and technologies that can help to transform
how air transportation systems operate, how new aircraft are
designed and manufactured, and how our Nation’s air transportation
system can reach unparalleled levels of safety and security.
Such tools and technologies will drive the next wave of innovation,
enabling missions to be performed in completely new ways and
creating new missions that were never before possible.
|
A collection of NASA’s research aircraft on
the ramp at the Dryden Flight Research Center
in July 1997: X-31, F-15, SR-71,
F-106, F-16XL Ship #2, X-38, Radio Controlled
Mothership, and X-36. |
NASA has been at the forefront of aeronautics research
for decades, and just recently celebrated the 90th anniversary
of its predecessor, the National Advisory Committee for
Aeronautics (NACA). From March 3, 1915, until its incorporation
into NASA on October 1, 1958, NACA provided technical advice
to the U.S. aviation industry and conducted cutting-edge
research in aeronautics. NACA was created by President
Woodrow Wilson, to “direct and conduct research and experimentation
in aeronautics, with a view to their practical solution.”
NASA has continued this tradition.
In the 1920s, NACA engineers developed a low-drag
streamlined cowling for aircraft engines, which all
aircraft manufacturers then adopted. This innovation
resulted in significant operating cost savings. NACA
engineers also demonstrated the advantages of mounting
engines into the leading edges of multi-engine aircraft
wings rather than suspending them, which also became
an industry standard.
Through the 1930s, NACA engineers developed several families
of airfoils. Many of these were successful as wing and
tail sections, propellers, and helicopter rotors used in
general aviation and in military aircraft.
During the 1940s, NACA researchers developed the laminar-flow
airfoil, which solved the problem of turbulence at the
wing trailing edge that limited aircraft performance. The
research helped pioneer advances in transonic and supersonic
flight. NACA also developed a supersonic wind tunnel, speeding
the advent of operational supersonic aircraft and helping
to determine the physical laws affecting supersonic flight.
In 1945, Robert Jones, one of the premier aeronautical
engineers of the 20th century, formulated the swept-back
wing concept to reduce shockwave effects at critical supersonic
speeds. Also in the mid-1940s, NACA engineers pioneered
research in thermal ice prevention systems for aircraft.
In 1952, NACA’s engineers formed the blunt body concept,
which suggested that a blunt shape would absorb only a
very small fraction of the heat generated during reentry
into Earth’s atmosphere. The principle was significant
for missile nose cones; the Mercury, Gemini, Apollo, and
Space Shuttle craft; and unmanned probes. That same year,
NACA began studying problems likely to be encountered in
space.
|
The Lunar Landing Training
Vehicle (LLTV) gave astronauts valuable training
in the critical final phases of the descent onto
the Moon. |
In 1954, NACA proposed development of a piloted research
vehicle to study the problems of flight in
the upper atmosphere and at hypersonic speeds. This
led to the development of the rocket-propelled X-15 research
airplane.
With NACA’s transformation into NASA
in 1958, research for space travel became a high-profile
endeavor. NASA and Bell Aerosystems Company developed a
Lunar Landing Training Vehicle (LLTV) simulator for the
Apollo Program. This allowed a pilot to make a vertical
landing in a simulated Moon environment. Donald “Deke”
Slayton, then NASA’s astronaut chief, said there was no
other way to simulate a Moon landing except by flying the
LLTV.
Four decades of supersonic-combustion ramjet (scramjet)
propulsion research culminated in 2004, with two successful
flights of the X-43A hypersonic technology demonstrator.
The X-43A attained a maximum speed of Mach 9.6, flying
freely under its own power. It set world airspeed records
for an aircraft powered by an air-breathing engine. The
flights proved that scramjet propulsion may be a viable
technology for powering future space-access vehicles and
hypersonic aircraft.
NASA will continue to develop and validate high-value technologies
that enable exploration and discovery. The Agency continues
its legacy work in aeronautics with breakthrough developments
in quieter supersonic and subsonic flight, and autonomous,
high-altitude, long-endurance robotic aircraft.
Currently, among its many aeronautics research endeavors,
NASA is working toward zero-emission aircraft; smoother,
safer airline flights; and elimination of low-visibility-induced
accidents.
APEX: Measuring Emissions So That Future Aircraft Fly Cleaner
NASA has been studying various types of emissions from
commercial aircraft to develop ways to reduce them and
protect the environment. In recent years, fine-particle
emissions from aircraft have been identified as possible
contributors to global climate changes and to lowering
local air quality. These emissions are produced when a
hydrocarbon fuel (such as modern jet fuel, which is primarily
kerosene) does not burn completely. Incomplete combustion
often occurs at the lower power settings used for aircraft
descent, idling, and taxiing. This produces fine carbon
particles, or soot, as well as particles of nonvolatile
organic compounds. In addition, engine erosion and small
amounts of metal impurities in jet fuel can be emitted
in engine exhaust.
|
The DC-8 airborne laboratory
flies three primary types of missions: sensor development,
satellite sensor verification, and basic research
studies of the Earth’s surface and atmosphere. |
Another type of particle emission is formed when exhaust
cools, converting volatile aerosols of sulfur compounds
and organic compounds to small, solid particles. These
types of emissions are not addressed by current international
regulations, which focus on visible smoke, but the international
community is concerned about the effects that these emissions
may have and is identifying possible regulations. In addition,
reducing all types of aircraft emissions is necessary for
the U.S aircraft industry to remain competitive in the
global market.
|
Data gathered by the
DC-8 airborne laboratory at flight altitude and
by remote sensing have been used for scientific
studies in archaeology, ecology, geography, hydrology,
meteorology, oceanography, volcanology, atmospheric
chemistry, soil science, and biology. |
Recently, Glenn took part in the successful Aircraft Particle
Emissions Experiment (APEX). NASA’s
DC-8 airborne laboratory was used with CFM-56 engines to
improve understanding of particle emissions from commercial
aircraft engines. It was the first and most extensive set
of data obtained about gaseous and particulate emissions
from an in-service commercial engine. Many different instruments
were used, and a tremendous amount of data was obtained.
NASA scientists ran tests to investigate the effects of
thrust and fuel type. The team used different engine operating
settings to vary thrust, and three different fuels were
used: a typical jet fuel, a fuel with high sulfur content,
and a fuel with high aromatic compound content. In addition,
the Environmental Protection Agency ran tests to simulate
landing-takeoff cycles to study the emissions that would
be created at an airport. It was the first time that so
many different groups had worked together to study so many
different aspects of the emissions from commercial aircraft
engines.
Smoothing Out the Skies
Passengers on a Delta Air Lines jet could have a smoother
ride, thanks to NASA-developed technology. Delta is installing
a special production-prototype radar, which can detect
turbulence associated with thunderstorms, on one of its
B737-800 aircraft. The radar, called the Turbulence Prediction
and Warning System (TPAWS), was developed for NASA’s Aviation
Safety and Security Program at Langley Research Center.
NASA teamed with Delta Air Lines, of Atlanta;
AeroTech Research (USA), Inc., of Newport News, Virginia;
and Rockwell Collins, of Cedar Rapids, Iowa, for the
in-service evaluation of the radar unit, which also includes
turbulence hazard prediction capabilities.
“The TPAWS technology is an enhanced turbulence detection
radar system, which detects atmospheric turbulence by measuring
the motions of the moisture in the air,” said Jim Watson,
the TPAWS project manager. “It is a software signal processing
upgrade to existing predictive Doppler wind shear systems,
also developed by NASA, that are already on airplanes.”
|
Dispatcher’s display
of turbulence-encounter reports integrated with
weather data. These reports are used to safely
guide Delta Air Lines flights in real time. |
The idea behind the turbulence detection system is to give
flight crews advanced warning, so they can avoid turbulence
encounters or advise flight attendants and passengers to
sit down and buckle up to avoid injury. Turbulence encounters
are hazardous, and they cost the airlines money and time
in the form of re-routing flights, late arrivals, and additional
inspections and maintenance to aircraft. Atmospheric turbulence
encounters are the leading cause of injuries to passengers
and flight crews in non-fatal airline accidents. Federal
Aviation Administration statistics show an average of 58
airline passengers are hurt in U.S. turbulence incidents
each year. Ninety-eight percent of those injuries happen
because people do not have their seatbelts fastened.
NASA researchers say the TPAWS radar can detect about 80
percent of all atmospheric turbulence encounters. It can
also detect thunderstorm-related turbulence at an average
of 3 to 5 minutes ahead of the aircraft. According to studies
done by Dryden Flight Research Center engineers, it takes
a little more than a minute and a half to get 95 percent
of passengers seated, carts stored, and flight attendants
secured. Delta flight crews will use and evaluate the technology
during regularly scheduled flights in the United States
and South America. The prototype is expected to fly for
6 to 9 months.
Researchers from NASA, the companies involved, and the
Federal Aviation Administration, will evaluate interim
and final results of the turbulence prediction radar system.
If the evaluation is successful, the technology may be
adopted for new and existing aircraft.
NASA has already tested TPAWS on a research aircraft based
at Langley. The TPAWS-equipped plane searched for turbulence
activity around thunderstorms for 8 weeks. The jet flew
within a safe distance of storms, so researchers could
experience the turbulence and compare the radar prediction
to how the plane responded to the encounters. After one
severe patch of turbulence, a NASA research pilot said
his confidence in the enhanced radar had “gone up dramatically,”
since the plane’s weather radar had shown nothing at the
same time the TPAWS display had shown rough skies ahead.
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