|In this artist’s concept, the Earth Departure Upper Stage and the Shepherding Spacecraft approach the Moon (above); the Earth Departure Upper Stage impacts at the south pole (below).|
To kick off the quest for lunar water ice, NASA announced
that a small, secondary payload spacecraft to be developed
Research Center will begin a trip to the Moon in
October 2008 to look for precious water.
The water-seeking spacecraft is called the Lunar CRater Observation and Sensing Satellite (LCROSS). It is known as a secondary payload spacecraft because it will begin its trip to the Moon on the same rocket as the Lunar Reconnaissance Orbiter (LRO), which is on a different mission to the Moon. The rocket, the Evolved Expendable Launch Vehicle, will launch from Kennedy Space Center.
The LCROSS spacecraft will arrive in the lunar vicinity independent of the LRO satellite. Prior to impacting the Moon, LCROSS will orbit Earth twice for about 80 days, and will then strike the lunar south pole in January 2009.
On the way to the Moon, the LCROSS spacecraft’s two main parts, the Shepherding Spacecraft and the Earth Departure Upper Stage, will remain coupled. As the spacecraft approaches the Moon’s south pole, the Earth Departure Upper Stage will separate, and will then impact a crater in the south pole area. A 2.2-million-pound plume from the Earth Departure Upper Stage crash will develop as the Shepherding Spacecraft heads in toward the Moon.
The Shepherding Spacecraft will fly through the plume, and instruments on the spacecraft will analyze the cloud to look for signs of water and other compounds. At the end of its mission, the satellite will itself become an impactor, creating a second plume visible to lunar-orbiting spacecraft and Earth-based observatories.
How We Will Get Back to the Moon
Before the end of the next decade, NASA astronauts will again explore the surface of the Moon. This time, they are going to stay, building outposts and paving the way for eventual journeys to Mars and beyond.
This journey begins soon, with the development of a new spaceship. Building on the best of past and present technology, NASA is creating a 21st century exploration system that will be affordable, reliable, versatile, and safe.
The centerpiece of this system is a new spacecraft designed to carry four astronauts
to and from the Moon, deliver up to six crewmembers and supplies to the International
Space Station (ISS), and support future missions to Mars.
The new Crew Exploration Vehicle (CEV) will be shaped like an Apollo capsule, but it will be significantly larger and include solar panels for power. The new ship will be built to minimize life-cycle costs. Designers are looking at the pros and cons of a variety of different systems that will ensure that the crew vehicle, as well as the launch and landing systems, are sustainable for long-term use by the next generation of space explorers.
Coupled with the new lunar lander, the system will send twice as many astronauts to the lunar surface as Apollo, and they can stay longer, with the initial missions lasting 4 to 7 days. While Apollo was limited to landings along the Moon’s equator, the new ship will carry enough propellant to land anywhere on the Moon’s surface.
Once a lunar outpost is established, crews could remain on the surface for up to 6 months. The capsule will also operate for up to 6 months in lunar orbit without a crew, eliminating the need for one astronaut to stay behind while others explore the surface.
The launch system that will get the crew off the ground builds on powerful, reliable propulsion elements. Astronauts will launch on a rocket made up of a longer shuttle solid rocket booster, with a second stage powered by a J-2X engine, like the kind used on the Apollo Saturn V rockets.
A second, heavy-lift system will use a pair of the longer solid rocket boosters and five liquid-fueled engines to put up to 125 metric tons in orbit—slightly more than the weight of a shuttle orbiter. This versatile system will be used to put the components needed to go to the Moon and Mars into orbit. The heavy-lift rocket may be modified to carry crew as well.
Best of all, the capsule will be 10 times safer than the shuttle because of an
escape rocket on top that can quickly blast the crew away if launch problems
develop. There also will be little chance of damage from launch vehicle debris,
since the capsule will sit on top of the rocket.
Early in the next decade, the new ship will begin to ferry crew and supplies to the ISS. Plans call for as many as six trips to the station a year. In the meantime, robotic missions will lay the groundwork for lunar exploration.
NASA plans to return humans to the Moon as early as 2018.
Here is how a mission will unfold:
A heavy-lift rocket blasts off, carrying a lunar lander and a “departure stage” needed to leave Earth’s orbit. The crew launches separately, docks its capsule with the lander and departure stage, and then heads for the Moon.
Three days later, the crew enters lunar orbit. The four astronauts climb into the lander, leaving the capsule to wait for them in orbit. After landing and exploring the surface for 7 days, the crew blasts off in a portion of the lander, docks with the waiting capsule, and then travels back to Earth. After a de-orbit burn, the service module portion of the capsule is jettisoned, exposing the heat shield for the first time in the mission. After a fiery descent through Earth’s atmosphere, parachutes deploy, the heat shield is dropped, and the capsule lands.
With a minimum of two lunar missions per year, momentum will build quickly toward
a permanent outpost. Crews will stay longer and learn to exploit the Moon’s resources,
while landers make one-way trips to deliver cargo. Eventually, the new system
could rotate crews to and from a lunar outpost every 6 months.
Planners are already looking at the lunar south pole as a candidate for an outpost, because of concentrations of hydrogen thought to be in the form of water ice and an abundance of sunlight to provide power.
These plans give NASA a huge head start in getting to Mars. The United States will already have the heavy-lift system needed to get there, as well as a versatile crew capsule capable of taking the crew to and from a Mars vehicle in low-Earth orbit. A lunar outpost just 3 days away from Earth will give NASA the needed practice of living on another world away from Earth, before making the longer trek to Mars.
NASA Team Develops Spacecraft Armor
Six NASA centers from across the country are joining together with one common goal: advanced development of a heat shield that will protect the next generation of space vehicles. The final flight version of the heat shield and ancillary support systems will be designed and manufactured by the CEV prime contractor when that contract is awarded.
As the CEV returns from future missions to the Moon, it will bore through Earth’s atmosphere at speeds exceeding 6.8 miles per second. Those speeds can generate temperatures that exceed 4,800 °F.
The space shuttle, by comparison, enters at a speed of 4.7 miles per second and sees a maximum temperature of 2,900 °F. The crew vehicle will see temperatures of up to 3,400 °F when reentering from low-Earth orbit.
The faster entry velocities, and especially the higher temperatures, will make providing for the safe return of NASA’s crew vehicle a real challenge. To reach this goal, a team comprised of engineers from six of NASA’s field centers will conduct atmospheric reentry materials and structures tests leading to the design and development of a new heat shield.
“You can think of the CEV heat shield as a large Frisbee-like disc that is attached to the bottom of the crew vehicle,” said James Reuther, Thermal Protection System Advanced Development Project (TPS ADP) manager at Ames.
The TPS ADP is led by Ames for the CEV Project Office. Teams from Langley Research Center, Johnson Space Center, Glenn Research Center, Kennedy Space Center, and the Jet Propulsion Laboratory (JPL) are collaborating in this effort.
NASA’s two large arcjet facilities at Ames and Johnson are home to experiments specifically designed to test heat shield materials under conditions that simulate the searing heat and pressure experienced during reentry. These arcjet tests will determine whether a current set of candidate TPS materials will provide the crew vehicle enough protection during its fiery descent back to Earth.
Thermal mechanical testing at Langley is leading toward a better understanding of the structural aspects of the TPS materials. Langley is also designing the attachment and separation system, as well as the carrier structure (used to hold onto the TPS material), for the heat shield.
Glenn researchers are working with Ames and Langley to develop the main seal for the heat shield. They are doing a state-of-the-art review of previously and currently used seal options, seal manufacturers, potential risks, and pros and cons for each option in order to provide recommended seal options with corresponding attributes and risks.
Engineers at Kennedy will conduct various non-destructive tests to analyze the quality of full-size manufactured demonstration units for the crew vehicle’s heat shield.
JPL engineers are working with Ames engineers to develop and document a robust set of TPS requirements and associated verification and validation plans for evaluating contractor implementations. They are also working with Langley engineers to design the attachment and separation system for the heat shield. They have completed a state-of-the-art review of previously and currently used mechanical attachment and separation options, and are now refining and analyzing one option being considered.
To remain on the proposed schedule of launching the CEV in 2014, NASA’s widespread TPS team is working to complete the advanced development and select the final TPS material and overall design of a durable heat shield by 2009.
“Unlike some of the other elements of the CEV design, the heat shield material selection and design is being run as an open competition,” said Reuther. “It is a real challenge to produce a heat shield design that can both protect the CEV from the extreme heat of entry and simultaneously be produced as a single 16.5-foot-diameter lightweight and robust dish.”
This advanced development is under the direction of the CEV project at Johnson.
George Sarver, manager of Ames’s CEV/Crew Launch Vehicle Support Office, concluded,
“NASA’s expertise in the field of thermal protection, across all of NASA’s centers,
is world class.”
NASA Launches Satellites for Weather, Climate, and Air Quality Studies
Two NASA satellites were launched in April from Vandenberg Air Force Base, California, on missions to reveal the inner secrets of clouds and aerosols, tiny particles suspended in the air.
CloudSat and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) thundered skyward atop a Boeing Delta II rocket. The two satellites will eventually circle approximately 438 miles above Earth in a Sun-synchronous polar orbit, which means they will always cross the equator at the same local time. Their technologies will enable scientists to study how clouds and aerosols form, evolve, and interact.
“Clouds are a critical but poorly understood element of our climate,” said Dr. Graeme Stephens, CloudSat principal investigator and a professor at Colorado State University. “They shape the energy distribution of our climate system and our planet’s massive water cycle, which delivers the fresh water we drink that sustains all life.”
“With the successful launch of CloudSat and CALIPSO, we take a giant
step forward in our ability to study the global atmosphere,” said Dr.
David Winker, CALIPSO principal investigator at Langley. “In the years
to come, we expect these missions to spark many new insights into the
workings of Earth’s climate and improve our abilities to forecast weather
and predict climate change.”
Each spacecraft will transmit pulses of energy and measure the portion of the pulses scattered back to the satellite. CloudSat’s Cloud-Profiling Radar is over 1,000 times more sensitive than typical weather radar. It can detect clouds and distinguish between cloud particles and precipitation. CALIPSO’s polarization lidar can detect aerosol particles and distinguish them from cloud particles. Lidar, similar in principle to radar, uses reflected light to determine the characteristics of the target area.
The satellites will fly in formation as members of NASA’s “A-Train” constellation, which also includes NASA’s Aqua and Aura satellites and a French satellite known as Parasol, for Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar. The satellite data will be more useful when combined, providing insights into the global distribution and evolution of clouds to improve weather forecasting and climate prediction.
CloudSat is managed by JPL, which developed the radar instrument with hardware contributions from the Canadian Space Agency; Colorado State University provides scientific leadership and science data processing and distribution; Ball Aerospace and Technologies Corporation, of Boulder, Colorado, designed and built the spacecraft; the U.S. Air Force and U.S. Department of Energy contributed resources; and American and international universities and research centers support the mission science team.
CALIPSO is a collaboration between NASA and the French space agency, Centre National
d’Etudes Spatiales (CNES). Langley is leading the CALIPSO mission and providing
overall project management, systems engineering, and payload mission operations;
Flight Center is providing support for system engineering and project
and program management; CNES is providing a Proteus spacecraft developed by Alcatel
Space, a radiometer instrument, and spacecraft mission operations; Hampton University,
in Hampton, Virginia, is providing scientific contributions and managing the
outreach program; Ball Aerospace developed the lidar and onboard visible camera;
Launch Services Program at Kennedy procured the mission’s launch and
provided management for the mission’s launch service.
NASA Scientists Achieve Breakthrough in Black Hole Simulation
NASA scientists have made a breakthrough in computer modeling that allows them to simulate what gravitational waves from merging black holes look like. The 3-D simulations, the largest astrophysical calculations ever performed on a NASA supercomputer, provide the foundation to explore the universe in an entirely new way.
According to Albert Einstein’s math, when two massive black holes merge, all of space jiggles like a bowl of gelatin as gravitational waves race out from the collision at light speed. Previous simulations had been plagued by computer crashes, as the necessary equations, based on Einstein’s theory of general relativity, were far too complex. Scientists at Goddard, however, have found a method to translate Einstein’s math in a way that computers can understand.
“These mergers are by far the most powerful events occurring in the universe, with each one generating more energy than all of the stars in the universe combined. Now we have realistic simulations to guide gravitational wave detectors coming online,” said Joan Centrella, chief of the Gravitational Astrophysics Laboratory at Goddard.
Similar to ripples on a pond, gravitational waves are ripples in space and time,
a four-dimensional concept that Einstein called spacetime. They have not yet
been directly detected. Furthermore, gravitational waves hardly interact with
matter and, thus, can penetrate the dust and gas that block the view of black
holes and other objects. They offer a new window to explore the universe and
provide a precise test for Einstein’s theory of general relativity. The National
Science Foundation’s ground-based Laser Interferometer Gravitational-Wave Observatory
and the proposed Laser Interferometer Space Antenna, a joint NASA-European Space
Agency project, hope to detect these subtle waves.
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Black hole mergers produce copious gravitational waves, sometimes for years, as the black holes approach each other and collide. Black holes are regions where gravity is so extreme that nothing, not even light, can escape their pull. They alter spacetime. Therein lies the difficulty in creating black hole models; space and time shift, density becomes infinite, and time can come to a standstill. Such variables cause computer simulations to crash.
These massive, colliding objects produce gravitational waves of differing wavelengths and strengths, depending on the masses involved. The Goddard team has perfected the simulation of merging, equal-mass, non-spinning black holes starting at various positions corresponding to the last two to five orbits before their merger.
With each simulation run, regardless of the starting point, the black holes orbited stably and produced identical waveforms during the collision and its aftermath. This unprecedented combination of stability and reproducibility assured the scientists that the simulations were true to Einstein’s equations. The team has since moved on to simulating mergers of nonequal-mass black holes.
Einstein’s theory of general relativity employs a type of mathematics called tensor calculus, which cannot easily be turned into computer instructions. The equations need to be translated, which greatly expands them. The simplest tensor calculus equations require thousands of lines of computer code. The expansions, called formulations, can be written in many ways. Through mathematical intuition, the Goddard team found the appropriate formulations that led to suitable simulations.
The simulations were performed on the Columbia supercomputer at Ames. Progress also has been made independently by several other groups, including researchers at the Center for Gravitational Wave Astronomy at the University of Texas, Brownsville, which is supported by NASA’s Minority University Research and Education Programs.
Stardust Mission Findings May Alter View of Comet Formation
To scientists’ surprise, samples from comet Wild 2 indicate that the formation of at least some comets may have included materials ejected by the early Sun to the far reaches of the solar system.
Scientists have found minerals formed near the Sun or other
stars in the samples returned to Earth by NASA’s Stardust
spacecraft in January. The findings suggest materials from
the center of the solar system could have traveled to the
outer reaches where comets formed. This may alter the way
scientists view the formation and composition
“The interesting thing is we are finding these high-temperature minerals in materials from the coldest place in the solar system,” said Donald Brownlee, Stardust principal investigator from the University of Washington, Seattle.
Scientists have long thought of comets as cold, billowing clouds of ice, dust, and gases formed on the edges of the solar system. But comets may not be so simple or similar; they may prove to be diverse bodies with complex histories. Comet Wild 2 seems to have had a more complex history than thought.
“We have found very-high-temperature minerals, which supports a particular model where strong bipolar jets coming out of the early Sun propelled material formed near to the Sun outward to the outer reaches of the solar system,” said Michael Zolensky, Stardust curator and co-investigator at Johnson. “It seems that comets are not composed entirely of volatile-rich materials but rather are a mixture of materials formed at all temperature ranges, at places very near the early Sun, and at places very remote from it.”
One mineral found in the material brought back by Stardust is olivine, a primary component of the green sand found on some Hawaiian beaches. It is among the most common minerals in the universe, but scientists were surprised to find it in cometary dust.
Olivine is a compound of iron, magnesium, and other elements. The Stardust sample is primarily magnesium. Along with olivine, the dust from Wild 2 contains high-temperature minerals rich in calcium, aluminum, and titanium.
Stardust passed within 149 miles of comet Wild 2 in January 2004, trapping particles from the comet in an exposed gel. Its return capsule parachuted to the Utah desert 2 years later, on January 15 of this year. The science canister with the Wild 2 sample arrived at Johnson on January 17. Samples have been distributed to approximately 150 scientists for study.
“The collection of cometary particles is greater than we ever expected,” said Peter Tsou, Stardust deputy principal investigator at JPL. “The collection includes about two-dozen large tracks visible to the unaided eye.”
The grains are tiny,
with most being smaller than a hair’s width. A single grain
of 10 microns, only one-hundredth of a millimeter, can be
sliced into hundreds of samples for scientists.
In addition to cometary particles, Stardust gathered interstellar
dust samples during its 7-year, 2.88 billion-mile journey.
A team at Johnson’s curatorial facility is carrying out a
detailed scanning of the interstellar samples. In doing so,
it will initiate the “Stardust@Home” project, which will
enable volunteers from the public to help scientists locate
The velocity of the sample return capsule that entered the
Earth’s atmosphere in January was the fastest of any human-made
object on record. It surpassed the record set in May 1969
during the return of the Apollo 10 Command Module.
JPL manages the Stardust mission for the Science Mission Directorate.
Cassini Discovers Potential Liquid Water on Enceladus
NASA’s Cassini spacecraft may have found evidence of liquid-water reservoirs that erupt in Yellowstone National Park-like geysers on Saturn’s moon, Enceladus. The rare occurrence of liquid water so near the surface raises many new questions about the mysterious moon.
“We realize that this is a radical conclusion—that we may have evidence for liquid water within a body so small and so cold,” said Dr. Carolyn Porco, Cassini imaging team leader at the Space Science Institute, of Boulder, Colorado. “However, if we are right, we have significantly broadened the diversity of solar system environments where we might possibly have conditions suitable for living organisms.”
High-resolution Cassini images show icy jets and towering plumes ejecting large quantities of particles at high speed. Scientists examined several models to explain the process. They ruled out the idea that the particles are produced by or blown off the moon’s surface by vapor created when warm water ice converts to a gas. Instead, scientists have found evidence for a much more exciting possibility: the jets might be erupting from near-surface pockets of liquid water above 0 °C, like cold versions of the Old Faithful geyser in Yellowstone.
“We previously knew of, at most, three places where active volcanism exists:
Jupiter’s moon, Io; Earth; and possibly Neptune’s moon, Triton. Cassini changed
all that, making Enceladus the latest member of this very exclusive club, and
one of the most exciting places in the solar system,” said Cassini scientist
Dr. John Spencer, of Southwest Research Institute.
“Other moons in the solar system have liquid-water oceans covered by kilometers
of icy crust,” said Dr. Andrew Ingersoll, imaging team member and atmospheric
scientist at the California Institute of Technology. “What is different here
is that pockets of liquid water may be no more than tens of meters below the
Other unexplained oddities now make sense. “As Cassini approached Saturn, we discovered that the Saturnian system is filled with oxygen atoms. At the time, we had no idea where the oxygen was coming from,” said Dr. Candy Hansen, Cassini scientist at JPL. “Now we know that Enceladus is spewing out water molecules, which break down into oxygen and hydrogen.”
Scientists are also seeing variability at Enceladus. “Even when Cassini is not
flying close to Enceladus, we can detect that the plume’s activity has been changing
through its varying effects on the ‘soup’ of electrically charged particles that
flow past the moon,” said Dr. Geraint H. Jones, Cassini scientist, magnetospheric
imaging instrument, Max Planck Institute for Solar System Research, Katlenburg-Lindau,
Scientists still have many questions: Why is Enceladus currently so active? Are other sites on Enceladus active? Might this activity have been continuous enough over the moon’s history for life to have had a chance to take hold in the moon’s interior?
“Our search for liquid water has taken a new turn,” said Dr. Peter Thomas, Cassini imaging scientist at Cornell University, in Ithaca, New York. “The type of evidence for liquid water on Enceladus is very different from what we’ve seen at Jupiter’s moon, Europa. On Europa, the evidence from surface geological features points to an internal ocean. On Enceladus, the evidence is direct observation of water vapor venting from sources close to the surface.”
In the spring of 2008, scientists will get another chance to look at Enceladus when Cassini flies within approximately 220 miles of the moon, though much work remains after Cassini’s 4-year prime mission is over.
“There is no question that, along with the moon Titan, Enceladus should be a very high priority for us. Saturn has given us two exciting worlds to explore,” said Dr. Jonathan Lunine, Cassini interdisciplinary scientist at the University of Arizona, Tucson.
Mars Rovers Advance Understanding of the Red Planet
Mars rovers Spirit
and Opportunity have been working overtime to help scientists
better understand ancient environmental conditions on the Red Planet. The rovers
are also generating excitement about the exploration of Mars outlined in the
for Space Exploration. They continue to find new variations of bedrock
in areas they are exploring on opposite sides of Mars. The geological information
they have collected adds evidence about ancient Martian environments that included
periods of wet, possibly habitable conditions.
“The extended journeys taken by the two rovers across the surface of Mars have allowed the science community to continue to uncover discoveries that will enable new investigations of the Red Planet far into the future,” said Mary Cleave, associate administrator for the Science Mission Directorate.
The rovers are currently on their third mission extension. During their 3-month primary missions, the rovers drove farther and examined more rocks than the prescribed criteria for success.
Opportunity has spent some considerable time this year examining bedrock exposures
along a route between two craters coined Endurance and Victoria.
Opportunity also found evidence of a long-ago habitat of
standing water on Mars.
Early this year, Spirit passed its second anniversary inside the Connecticut-sized Gusev Crater. Initially, Spirit did not find evidence of much water, and hills that might reveal more about Gusev’s past were still mere bumps on the horizon. By operating eight times as long as planned, Spirit was able to climb up those hills, examine a wide assortment of rocks, and find mineral fingerprints of ancient water.
While showing signs of wear, Spirit and Opportunity are still being used to their maximum remaining capabilities. On Spirit, the teeth of the rover’s rock abrasion tool are too worn to grind the surface off any more rocks, but its wire-bristle brush can still remove loose coatings. The tool was designed to uncover 3 rocks, but it actually exposed the interiors of 15 rocks.
On Opportunity, the steering motor for the front right wheel stopped working. A motor at the shoulder joint of the rover’s robotic arm showed symptoms of a broken wire in the motor winding. Opportunity can still maneuver with its three other steerable wheels, however. Its shoulder motor still works when given extra current and the arm is still useable without that motor.
JPL manages the Mars Exploration Rover mission for the Science Mission Directorate.
NASA’s New Horizons Mission Launched toward Pluto
The first mission to Pluto, recently designated as a dwarf planet by the International Astronomical Union, is under way after the successful January la unch of NASA’s New Horizons spacecraft from Cape Canaveral Air Force Station.
“Right now, what we know about Pluto could be written on the back of a postage stamp,” explained Dr. Colleen Hartman, deputy associate administrator for the Science Mission Directorate. “After this mission, we’ll be able to fill textbooks with new information.”
1,054-pound, piano-sized spacecraft is the fastest ever launched.
It sped away from Earth at approximately 36,000 miles per
hour, on a trajectory that will take it more than 3 billion
miles toward its primary science target in what is considered
the “third zone” of our solar system. New Horizons will zip
past Jupiter for a gravity assist and science studies in
February 2007, and conduct the first close-up, in-depth study
of Pluto and its moons in summer 2015. As part of a potential
extended mission, the spacecraft would then examine one or
more additional objects in the Kuiper
Belt, the region of ancient, icy, rocky
bodies (including Pluto) far beyond Neptune’s orbit.
“This is the gateway to a long, exciting journey,” said Glen Fountain, New Horizons project manager from the Johns Hopkins Applied Physics Laboratory (where the mission is managed and where the spacecraft was designed and built). “The team has worked hard for the past 4 years to get the spacecraft ready for the voyage to Pluto and beyond; to places we’ve never seen up close. This is a once-in-a-lifetime opportunity, in the tradition of the Mariner, Pioneer, and Voyager missions, to set out for first looks in our solar system.”
After the Jupiter encounter—during which New Horizons will train its science instruments on the large planet and its moons—the spacecraft will “sleep” in electronic hibernation for much of the cruise to Pluto. Operators will turn off all but the most critical electronic systems and check in with the spacecraft once a year to check out these systems, calibrate the instruments, and perform course corrections, if necessary. Between the in-depth checkouts, New Horizons will send back a beacon signal each week to give operators an instant read on spacecraft health. The entire spacecraft, drawing electricity from a single radioisotope thermoelectric generator, operates on less power than a pair of 100-watt household light bulbs.
New Horizons is the first mission in NASA’s New Frontiers Program of medium-class spacecraft exploration projects. The mission team also includes Goddard, JPL, the U.S. Department of Energy, Ball Aerospace, The Boeing Company, Lockheed Martin Corporation, Stanford University, University of Colorado, and KinetX, Inc., among a number of other partners.
The National Academy of Sciences ranked the exploration of the third zone—Pluto, its moons (Charon, in particular), and the Kuiper Belt—among the highest priorities for space exploration, citing the fundamental scientific importance of these bodies to advancing understanding of our solar system.
Mars-Orbiting Cameras Make Debut as NASA Craft Adjusts Orbit
In other Mars news, researchers are now releasing the very first Mars images taken from the science cameras on NASA’s Mars Reconnaissance Orbiter, launched in August 2005 to study whether the fourth planet from the Sun offered enough water to ever provide a habitat for life and to identify potential landing sites for future Mars missions.
Images taken by the orbiter’s Context Camera and Mars Color Imager during the
first tests of those instruments confirm the performance capability of the cameras—even
though the test images were taken from nearly 10 times as far from the planet
as the spacecraft will be once it finishes reshaping its orbit.
“The test images show that both cameras will meet or exceed their performance requirements once they’re in the low-altitude science orbit. We’re looking forward to that time with great anticipation,” said Dr. Michael Malin of San Diego-based Malin Space Science Systems, Inc. Malin is team leader for the Context Camera and principal investigator for the Mars Color Imager.
The cameras took the test images 2 weeks after the orbiter’s March 10 arrival at Mars and before the start of aerobraking, a process of reshaping the orbit by using controlled contact with the Martian atmosphere. In mid-April, the spacecraft began its dip into the upper atmosphere of Mars. The orbiter also took this time to fly in very elongated loops around the planet. Each circuit lasted about 35 hours and took the spacecraft about 27,000 miles away from the planet before swinging it back in close.
After the spacecraft gets into the proper orbit for its primary science phase, the six science instruments onboard will begin their systematic examination of Mars. The Mars Color Imager will view the planet’s entire atmosphere and surface everyday to monitor changes in clouds, wind-blown dust, polar caps, and other changeable features. Images from the Context Camera will have a resolution of 20 feet per pixel, allowing surface features as small as a basketball court to be discerned. The images will cover swaths 18.6 miles wide. The Context Camera will also show how smaller areas examined by the High Resolution Imaging Science Experiment camera (which will have the best resolution ever achieved from Mars orbit) and by the mineral-identifying Compact Reconnaissance Imaging Spectrometer fit into the broader landscape. This will ultimately allow scientists to watch for small-scale changes in the broader coverage area.
“Mars Reconnaissance Orbiter is a quantum leap in our spacecraft and instrument capabilities at Mars,” said James Graf, the mission’s project manager at JPL. “Weighing 4,806 pounds at launch, the spacecraft will be the largest ever to orbit Mars. The data rate from the orbiter at Mars back to Earth will be three times faster than a high-speed residential telephone line. This rate will enable us to return a tremendous amount of data and dramatically increase our understanding of this mysterious planet.”
Work Continues on Ultra-High Bypass Ratio Turbofan Engines
In aviation research, the Subsonic Fixed Wing project is pushing engine and airframe architectures beyond today’s “tube and wing” configurations by optimizing the integration of airframe and propulsion systems. A key to improving performance and lowering aircraft noise is the development of higher bypass ratio engines for higher efficiency and reduced engine noise. NASA has worked closely with Pratt & Whitney for 15 years to develop technologies needed to enable ultra-high bypass ratio engines.
In the 1990s, the Advanced Ducted Propulsor was developed through scale model fan tests in wind tunnels at Glenn and Langley and an engine demonstrator in the 40- by 80-foot wind tunnel at Ames. (During this time, the emphasis was on large and medium twin-engine aircraft performing long-duration flights.) Higher efficiencies were obtained by lowering the rotational fan tip speeds to about 840 feet per second during takeoff, which reduced the shock-related losses associated with current turbofan engines. The noise was reduced by lowering the fan pressure ratio to about 1.29 (compared to > 1.53 from today’s engines) and lowering the jet exhaust velocity. Variable pitch fans were developed to provide reverse thrust for landing and taxi operations.
Within the last 5 years, the emphasis for new technology
development shifted to small twin-engine aircraft. Based
on Advanced Ducted Propulsor technologies, a new engine was
identified by Pratt & Whitney called the Advanced Geared
Turbofan. The engine cycle parameters were similar to the Advanced Ducted Propulsor,
but the fan tip speed was increased to about 1,030 feet per second and the variable
pitch fan was replaced with a variable area nozzle. Fan noise predictions and
data obtained by NASA from several tests showed that the fan pressure ratio was
controlling the broadband noise and the overall noise levels could be comparable
to the Advanced Ducted Propulsor, as long as the tip speed did not increase to
where the shock-related noise sources dominated. Pratt & Whitney
anticipated additional noise and performance benefits from
using a fixed-pitch fan that reduced losses at the hub and
tip. NASA tested a model fan (representative of the GE90
cycle) and showed that variable area nozzles can provide
additional noise reduction and performance benefits that
are expected to help the new Advanced Geared Turbofan.
In August 2006, NASA conducted a cooperative model fan test with Pratt & Whitney in a 9- by 15-foot wind tunnel at Glenn to quantify the aerodynamic and acoustic characteristics of the Advanced Geared Turbofan. The results are being used for an engine demonstrator that Pratt & Whitney will fund and test in late 2007.
Through the Subsonic Fixed Wing project, NASA will continue working with Pratt & Whitney to test advanced technologies for additional noise, emissions, and performance improvements, with the possibility of testing them in engines that will be developed for future small twin-engine aircraft. NASA projects it may be possible to reduce the noise levels from the current 14 cumulative Effective Perceived Noise Level in decibels (EPNdB) below Stage 3, to levels ranging from 38 to 42 EPNdB below Stage 3. Specific fuel consumption will be reduced by about 8 percent relative to engines flying today and advanced combustor designs will reduce emissions such as nitrogen oxide by about 70 percent relative to the Committee on Aviation Environmental Protection standards.
The Advanced Geared Turbofan represents a significant advance to engine architectures that will be viewed as a technology breakthrough for ultra-high bypass ratio turbofans, just as the introduction of the GE90 engine in the 1990s paved the way for higher bypass ratio engines.
The Aeronautics Research Mission Directorate’s Aviation Safety Program is working with the Federal Aviation Administration (FAA) and the commercial aviation community to develop and test new data-mining tools that will enable users to proactively identify, analyze, and correct systemic safety issues that affect commercial aviation. This activity also contributes to the Joint Planning and Development Office’s (JPDO) safety initiative to assess the safety of the Next Generation Air Transportation System.
The Commercial Aviation Safety Team, which represents the aviation industry, the JDPO, and the FAA, and NASA, saw a need to move beyond the current historic, accident-based information to a diagnostic analysis of information extracted from Flight Operational Quality Assurance (FOQA) flight-recorded data and Aviation Safety Action Program (ASAP) incident reports being collected by air carriers. In recognition of this need, the industry established a Voluntary Aviation Safety Information-sharing Process (VASIP) to agree upon a process for the commercial aviation industry and the FAA to collect and share safety-related information. NASA clearly had the institutional background, resources and expertise necessary to develop the analytical tools for extracting and integrating information from large, distributed, and diverse (numerical and textual) data sources that were needed to enable the VASIP.
The Aeronautics Research Mission Directorate, working in a collaborative partnership with participating airlines, the FAA, and other organizations, started the Information-Sharing Initiative in June 2004. The goal of this initiative is to demonstrate operational programs for both Distributed National FOQA Archive data and Distributed National ASAP Archive data by September 30, 2006. Upon completion of the demonstration, aviation industry decision makers will use information from these two national database to proactively correct systemic safety issues.
The FOQA and ASAP databases are only two of the many safety-related data sources currently being collected across the industry. Information must be extracted from these other sources and integrated to gain a better understanding of the problems and to determine appropriate interventions. The industry sees a successful demonstration as the foundation upon which to expand and enhance the national archives of aviation safety-related data.
Ultimately, the entire aviation industry will benefit from a proactive approach to managing systemic safety risks. The flying public will benefit from an airline industry that is able to maintain its phenomenal safety record despite projected increases in air travel.
Future ATM Concepts Evaluation Tool
The Future ATM Concepts Evaluation Tool (FACET) is a flexible Air Traffic Management (ATM) simulation environment technology that has been established for exploring, developing, and evaluating advanced ATM concepts under NASA’s Airspace Systems Program. FACET can operate in a playback, simulation, live, or hybrid mode on a laptop computer, using the FAA’s Enhanced Traffic Management System (ETMS) data along with wind and weather data from the National Oceanic and Atmospheric Administration.
Examples of advanced concepts that have been developed and tested in FACET include aircraft self-separation, integrated aircraft and space launch vehicle operations, aggregate flow models of the National Airspace System, and reroute conformance monitoring. These concepts were deployed in the FAA’s operational ETMS system.
The success of FACET has lead to its adoption by the FAA, airlines, universities, and numerous companies. The most noteworthy example of FACET-derived technologies being adopted for commercial interests is the recent integration of FACET with the Flight Explorer software system, from Flight Explorer, Inc., of McLean, Virginia. Flight Explorer is the world’s leading aircraft situation display with an installed base of over 5,000 systems, according to the company. Its customers include 80 percent of all major U.S. airlines, 22 regional airlines, all cargo carriers, and executive jet operators. The first two FACET features available for commercial use are the sector and airport demand overlays that alert airspace users to forecasted demand and capacity imbalances. With this new information, airspace users will be able to develop better flight-routing strategies that save fuel, preserve airline schedules, and reduce passenger delays and missed connections. Future releases of Flight Explorer will incorporate additional FACET capabilities, such as optimal route generation.
The integration of FACET with Flight Explorer was initiated in 2005 with the signing of a Space Act Agreement between NASA and Flight Explorer, Inc. Key FACET capabilities, such as sector demand overlays, were subsequently made available to the commercial market through a nonexclusive worldwide licensing agreement. Overall, the FACET-Flight Explorer integration effort has been an extremely successful venture and feedback from the user community has been very supportive.
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