Posted on by Fraser Cain

Envisat Watches Hurricane Frances

Hurricanes are one of those forces of nature that can only fully be captured by satellite imagery. For Hurricane Frances, currently thundering towards the United States coast, ESA’s Envisat is going one better, peering through the hurricane from top to bottom, even helping to ‘see’ under the waves to map hidden forces powering the storm.

As its 235-km-per-hour winds passed the Bahamas, Frances was heading for landfall on the Florida coast some time on Saturday, and three quarters of a million Americans are in the process of evacuating their homes. To wait and watch for Frances might be suicidal for human beings, but space-based observers such as Envisat observe its passage without danger.

“Because of Envisat’s multi-sensor capability, we can slice right through the hurricane with just a single satellite,” explained Jos? Achache, ESA Director of Earth Observation Programmes.

“Effectively Frances is taken apart for meteorologists to study. The data returned by Envisat includes cloud structure and height at the top of the hurricane, wind and wave fields at the bottom, sea surface temperature and even sea height anomalies indicative of upper ocean thermal conditions that influence its intensity.”

Important processes occur at a range of altitudes and locations throughout a hurricane – basically a large powerful storm centred around a zone of extreme low pressure.

Strong low-level surface winds and bands of intense precipitation combine with strong updrafts and outflows of moist air at higher altitudes, with energy released as rainy thunderstorms. Until now, the only reliable source of such high-resolution measurements at different altitudes was from aircraft flown directly through the hurricane.

Envisat carries both optical and radar instruments, enabling researchers to observe high-atmosphere cloud structure and pressure in the visible and infrared spectrum, while at around the same time using radar backscatter to measure roughness of the sea surface and so derive the wind fields just over it.

Those winds converging on the low-pressure eye of the storm are what ultimately determine the spiralling cloud patterns that are characteristic of a hurricane.

Florida-based scientists have begun to take advantage of this unique single-spacecraft combination of instruments ? the Medium Resolution Imaging Spectrometer (MERIS) and Advanced Synthetic Aperture Radar (ASAR) ? as hurricane season gets into full swing.

The University of Miami’s Centre for Southeastern Tropical Advanced Remote Sensing (CSTARS) ground station has an agreement to acquire ASAR and MERIS data direct from Envisat, with ERS-2 wind scatterometer data set to follow in the near future. Their access to Envisat data has come just as the second hurricane in less than a month is heading towards the Florida coast.

“With MERIS and ASAR, Envisat can image both the ocean and atmosphere pretty much simultaneously, which is a very useful capability during hurricane season,” said Hans Graber, Professor of Applied Marine Physics at the University of Miami and Co-Director of CSTARS.

While MERIS returns detail on the swirling clouds at the top of the hurricane, ASAR pierces right through the clouds to show the wind-wracked face of the sea beneath the storm.

“Specifically in terms of Frances, the eye of the hurricane seems to be rolling a lot right now from the top of the clouds, looking quite unstable, the information from an ASAR image should help localise its size and position on the ocean,” Graber said. “And wind fields around the eye wall can be derived from ASAR data ? right now all we have to go on are measurements from the hurricane hunter planes that fly right through the storm.”

Simultaneous MERIS and ASAR acquisitions are planned for Friday by CSTARS, even as the storm comes closer to predicted landfall the following morning.

“Our current activity is along the lines of a shakedown ? we’re investigating how this can be used,” added Graber. “Our final goal is to get this working on an operational basis during hurricane season. We have a deal to use radar data from the Canadian Space Agency, and also have access to other satellite resources for high temporal coverage of the affected region.

“The potential is there to extract a large amount of useful information which can help the US National Hurricane Center increase the accuracy of their hurricane predictions and reduce danger to the public.”

Another instrument aboard Envisat is being used to take the temperature of Frances, both down at the surface of the ocean and at the heights of its towering clouds.

Water temperatures are the main underlying energy reservoir powering Frances; together with the correct atmospheric conditions, they need to exceed 26?C in order to form and maintain a tropical cyclone. Envisat’s Advanced Along Track Scanning Radiometer (AATSR) works like a space-based thermometer, acquiring the temperature of the sea surface down to a fraction of a degree.

Meanwhile AATSR also returns useful atmospheric data, measuring the temperature of the top of hurricane clouds ? the higher into the atmosphere they extend, the colder they are – and also deriving their ice content.

“We produced a combined AATSR sea surface temperature and cloud top temperature image, which shows the sea surface temperature to be as high as 29?C in the area,” remarked Carsten Brockmann of Brockmann Consult, a German company processing both MERIS and AATSR hurricane imagery. “This two-sensor combination gives meteorologists a lot of information to help them understand the dynamics of the hurricane and better predict its development.”

AATSR information can be correlated with MERIS data cloud height and development to gain a good estimate of the hurricane’s precipitation potential, and improve understanding of how this relates to its overall intensity. Condensation of water vapour releases latent heat, which warms the vicinity of the hurricane eye. This in turn evaporates more surface water and feeds the heat engine powering the hurricane.

Studying hidden depths that fuel the storm
The thermal energy of warm water, which partly powers a hurricane, is known as tropical cyclone heat potential (TCHP).

Oceanic features, such as warm core rings, eddies, and the Gulf Stream, represent a source of enhanced heat fluxes to the atmosphere that may cause the strengthening of tropical cyclones, such as hurricanes.

Warm waters may extend to at least 100 meters beneath the surface in many of these oceanic features, representing waters of very high heat content. Several hurricanes have intensified when their tracks pass over eddies or other masses of warm water with high TCHP values.

For example, in 1995 Hurricane Opal suddenly intensified in the Gulf of Mexico after passing over a warm ring with TCHP values of up to six times the threshold to sustain a tropical cyclone.

Previously, researchers used sea surface temperature alone to estimate the role of the upper ocean thermal conditions on hurricane intensification. The problem with this is that the sea surface temperature measured by AATSR or comparable satellite instruments may not by themselves show these warm upper ocean features, particularly during summer months in tropical regions.

In the past these upper ocean features have gone unseen by satellite-based temperature sensors because they are effectively camouflaged beneath a very shallow and stable layer of warmer water.

Tropical cyclone wind forces easily erode this thin upper layer by mixing the upper waters to depths that may go down to 100 meters, giving the tropical cyclones the potential to absorb ocean thermal energy, if conditions are appropriate. Now, estimates of TCHP based on satellite observations of sea surface temperature and sea surface height can detect these features.

Researcher Gustavo Goni, Joaquin Trinanes and Peter Black of the US National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML) are working on this original methodology to detect these warm water masses and to compute their tropical cyclone heat potential values using several satellite sensors including one on Envisat.

“These water features are critical for identifying regions of high TCHP values that may potentially contribute to the intensification of a hurricane?, Goni explained. “These regions of high TCHP values provide the hurricanes with the opportunity to absorb much more thermal energy if overall conditions are right. My research is taking advantage of the fact that these warm water masses cause an upward elevation in ocean height of up to 30 cm. Such sea height anomalies can then be mapped with space-based radar altimeter data.”

Radar altimeters, such as the Radar Altimeter-2 instrument on Envisat, fire hundreds of radar pulses down to Earth every second, and by timing their return down the nanosecond can measure sea height to a maximum accuracy of two centimetres from hundreds of kilometres above the Earth.

The US Naval Research Laboratory (NRL) combines Envisat RA-2 data with data from similar radar altimeters aboard the Jason-1 and GFO satellites to enhance overall accuracy and spatial and temporal coverage, forming the source for altimetry products which, in turn, form the basis for NOAA/AOML-produced maps of tropical cyclone heat potential depicting the upper ocean thermal conditions, shown here overlaid against Hurricane Frances’ track so far.

“At this time I use this product only for research purposes, providing an enhanced understanding of the life of a hurricane. However, analogous products are being produced and used operationally for forecasting by the National Hurricane Center”, Goni concluded.

Altimetry-based wind speed and wave height products are also distributed by the French firm Collecte Localisation Satellites (CLS), and can reveal sea surface features related to the presence of hurricanes.

Envisat results to be revealed
Launched in March 2002, ESA’s Envisat satellite is an extremely powerful means of monitoring the state of our world and the impact of human activities upon it. Envisat carries ten sophisticated instruments to observe and monitor the Earth’s atmosphere, land, oceans and ice caps, maintaining continuity with the Agency’s ERS missions started in 1991.

After two and a half years in orbit, more than 700 scientists from 50 countries are about to meet at a special symposium in Salzburg in Austria to review and discuss early results from the satellites, and present their own research activities based on Envisat data.

Starting on Monday, the Envisat Symposium will address almost all fields of Earth science, including atmospheric chemistry, coastal studies, radar and interferometry, winds and waves, vegetation and agriculture, landslides, natural risks, air pollution, ocean colour, oil spills and ice.

There are over 650 papers being presented at the Symposium, selected by peer review. Presentations will include results on the Prestige oil spill, last year’s forest fires in Portugal, the Elbe flooding in 2002, the evolution of the Antarctic ozone hole, the Bam earthquake and pollution in Europe.

Numerous demonstrations are planned during the week in the ESA Exhibit area. An industrial consortium exhibit on the joint ESA-European Commission Global Monitoring for Environment and Security (GMES) initiative is also planned.

Original Source: ESA News Release

Posted on by Fraser Cain

Be Safe Florida

At the time I’m writing this, Hurricane Frances is bearing down on Florida, and should make landfall within the next 36 hours. More than a million people have been ordered to evacuate their homes to avoid what could be the worst hurricane in more than a decade to strike the coast. Unfortunately, it looks like NASA’s Kennedy Space Center is right on target for the storm, and it could be hit by the most powerful part, called the “north wall”. KSC has been evacuated, but the three space shuttles are secured in a building designed to survive winds of 168 kph (105 mph) – Frances has gotten to 233 kph (145 mph). It’s going to be a nailbiter.

If you live in the area, definitely follow the evacuation instructions. I hope everyone stays as safe as possible.

Fraser Cain
Publisher
Universe Today

Posted on by Fraser Cain

Hot and Hotter

One of the Sun’s greatest mysteries is about to be unravelled by UK solar astrophysicists hosting a major international workshop at the University of St Andrews from September 6-9th 2004. For years scientists have been baffled by the ‘coronal heating problem’: why it is that the light surface of the Sun (and all other solar-like stars) has a temperature of about 6000 degrees Celsius, yet the corona (the crown of light we see around the moon at a total eclipse) is at a temperature of two million degrees?

Understanding our nearest star is important because its behaviour has such an immense impact on our planet. This star provides all the light, heat and energy required for life on Earth and yet there is still much about the Sun that is shrouded in mystery.

“The problem is like an Astrophysics X-file! It is totally counter intuitive that the Sun’s temperature should rise as you move away from the hot surface,” explains Dr Robert Walsh of the University of Central Lancashire and co-organiser of the workshop. “It is like walking away from a fire and suddenly hitting a hotspot, thousands of times hotter than the fire itself.”

Using the joint ESA/NASA satellite, the Solar and Heliospheric Observatory (SOHO), along with another NASA mission called TRACE, researchers have gathered enough data to form two rival theories to explain what has been termed ‘coronal heating’. It is now believed that the Sun’s strong magnetic field is the culprit behind this unique phenomenon. At this SOHO workshop, scientists from the UK and around the world will look at the evidence for these two explanations and try to untangle the clues we now have available to us.

Walsh continues, “SOHO’s contribution to the research has been so important because for the first time we can take simultaneous magnetic and extreme ultraviolet images of the Sun’s atmosphere, allowing us to study the changes in the magnetic field at the same time as the corresponding effect in the corona. Then, using sophisticated computer simulations, we have constructed 3d models of the coronal magnetic field that can be compared with SOHO’s observations.”

One possible mechanism for coronal heating is called ‘wave heating’. Prof Alan Hood from the Solar and Magnetospheric Theory Group at St. Andrews explains: “The Sun has a very strong magnetic field which can carry waves upwards from the bubbling solar surface. Then these waves dump their energy in the corona, like ordinary ocean waves crashing on a beach. The energy of the wave has to go somewhere and in the corona it heats the electrified gases to incredible temperatures.”

The other rival mechanism is dependent on twisting the Sun’s magnetic field beyond breaking point. Prof Richard Harrison of the UK’s Rutherford Appleton Laboratory says “The Sun’s magnetic field has loops, known to be involved in the processes of sun spots and solar flares. These loops reach out into the Sun’s corona and can become twisted. Like a rubber band, they can become so twisted that eventually they snap. When that happens, they release their energy explosively, heating the coronal gases very rapidly”.

The Sun is the only star astronomers can study in close detail and many questions remain. The workshop will also look forwards to future missions such as Solar-B, STEREO and Solar Orbiter that all have important UK involvement through PPARC.

Original Source: PPARC News Release

Posted on by Fraser Cain

Rover’s Grinder Working Again After Glitch

NASA’s Mars Exploration Rover Opportunity has resumed using its rock abrasion tool after a pebble fell out that had jammed the tool’s rotors two weeks ago.

The abrasion tool successfully spun a wire brush late Monday to scrub dust off two patches of a rock inside “Endurance Crater,” and engineering data received Tuesday confirmed that the tool is fully recovered. Rover wranglers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., plan to use the tool’s grinding rotor next to cut a hole exposing the interior of the rock.

“We’re delighted to be using Opportunity’s rock abrasion tool again,” said Dr. Stephen Gorevan of Honeybee Robotics, New York, lead scientist for that tool on both rovers. “We had planned to kick out that pebble by turning the rotors in reverse, but just the jostling of the rover’s movements seems to have shaken it loose even before we tried that. The rock abrasion tool has functioned beyond engineering expectations as a window for Mars Exploration Rover science. The new imaging consultation makes it clear that not only does the tool appear to be undamaged, but also that its teeth have not worn very much at all.”

Opportunity and its twin, Spirit, have each conducted more than four months of bonus exploration and discoveries after successfully completing their three-month primary missions on Mars. Opportunity’s rock abrasion tool has now been used 18 times to grind into rocks and five times to brush rocks. Spirit’s tool has ground nine times and brushed 28 times. The criteria set in advance for successful use of the abrasion tools was for each rover to grind at least one rock.

Mars and Earth are approaching the point in their orbits when Mars, on Sept. 16, will pass nearly behind the Sun, a geometry called “conjunction.” For several days around conjunction, the energetic environment close to the Sun will interfere with radio communications between the two planets. Rover operators have planned a hiatus in sending up daily commands. The rovers will use longer-term instructions to continue doing daily research and to attempt daily communications until the conjunction period is over.

“Based on experience with other spacecraft, we expect that when the Mars-Sun-Earth angle is 2 degrees or less, the ability to successfully communicate degrades rapidly,” said JPL systems engineer Scott Doudrick, who has been organizing conjunction operations for both rovers. “To be cautious, we’re allowing three days on either side of that period.”

The planned gap in sending daily plans runs for about 12 days beginning Sept. 8 for Spirit and Sept. 9 for Opportunity. The rovers will be instructed ahead of time to continue doing atmospheric operations and Moessbauer spectrometer readings daily during that period. No movements of the wheels or the robotic arms are in the conjunction-period plans, but the camera masts may move for making observations. The rovers also will continue communicating daily with NASA’s Mars Odyssey orbiter and will also attempt to communicate directly with Earth.

“The science team gets some time off from the daily planning cycle, but we will have a full spacecraft team every day, so we will be able to respond quickly if the rovers communicate a problem to us and there’s a good reason for emergency commands,” Doudrick said.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Science Mission Directorate, Washington. Additional information about the project is available from JPL at http://marsrovers.jpl.nasa.gov/ and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Contractors Selected for New Space Vision

NASA today awarded the first contracts to conduct preliminary concept studies for human lunar exploration and the development of the crew exploration vehicle. Eleven companies were selected.

NASA’s Exploration Systems Mission Directorate Associate Administrator retired Navy Rear Adm. Craig E. Steidle, said, “These study contracts reflect NASA’s new commitment to find the best outside expertise that will work in partnerships to benefit the nation’s goals for space exploration. We are developing a sustained and affordable human and robotic program that will explore the solar system and beyond. We will accomplish this using the same ingenuity, commitment and unwavering determination that forged the success of the Apollo program.”

The contracts, which total approximately $27 million, with a possible option worth an additional $27 million, are a result of the Concept Exploration and Refinement Broad Agency Announcement issued in May 2004.

The contracts will be awarded initiating a six-month base period, with a six-month option that may be exercised at the government’s discretion. Options may be exercised based on several factors, including the quality of performance during the base period, fiscal constraints and overall support to the Vision for Space Exploration. The Vision for Space Exploration gives NASA a new focus for a sustained and affordable human and robotic space exploration program to explore the solar system and beyond.

The contracts are in two categories or concept areas. The first area is preliminary concepts for human lunar exploration. The selected companies for “concept 1” and the value of their contracts are:

Raytheon, Tucson, Ariz. — Base: $994,157; Option: $998,529
SAIC, Houston — Base: $996,616; Option: $998,539
SpaceHAB Corp., Webster, Texas — Base: $995,603; Option: $998,907

The second category consists of preliminary concepts for the crew exploration vehicle and human lunar exploration. The selected companies for “concept 2” and the value of their contracts are:

Andrews Space Inc., Seattle — Base: $2,999,988; Option: $2,999,941
Draper Labs, Cambridge, Mass. — Base: $2,988,083; Option: $2,945,357
Lockheed Martin Corp., Denver — Base: $2,999,742; Option: $2,999,920
Northrop Grumman Corp., El Segundo, Calif. — Base: $2,958,753; Option: $2,999,473
Orbital Sciences Corp., Dulles, Va. — Base: $2,998,952; Option: $2,994,259
Schafer, Chelmsford, Mass. — Base: $2,999,179; Option: $2,997,804
The Boeing Co., Huntington Beach, Calif. — Base: $2,998,203; Option: $2,998,346
t-Space, Menlo Park, Calif. — Base: $2,999,732; Option: $2,939,357

For information about the Office of Exploration Systems on the Internet, visit:

http://exploration.nasa.gov/

For information about NASA on the Internet, visit:

http://www.nasa.gov

Original Source: NASA News Release

Posted on by Fraser Cain

Supernova in Nearby Galaxy NGC 2403

The explosion of a massive star blazes with the light of 200 million Suns in this NASA Hubble Space Telescope image. The arrow at top right points to the stellar blast, called a supernova. The supernova is so bright in this image that it easily could be mistaken for a foreground star in our Milky Way Galaxy. And yet, this supernova, called SN 2004dj, resides far beyond our galaxy. Its home is in the outskirts of NGC 2403, a galaxy located 11 million light-years from Earth. Although the supernova is far from Earth, it is the closest stellar explosion discovered in more than a decade.

The star that became SN 2004dj may have been about 15 times as massive as the Sun, and only about 14 million years old. (Massive stars live much shorter lives than the Sun; they have more fuel to “burn” through nuclear fusion, but they use it up at a disproportionately faster rate.) A team of astronomers led by Jesus Maiz of the Space Telescope Science Institute discovered that the supernova was part of a compact cluster of stars known as Sandage 96, whose total mass is about 24,000 times the mass of the Sun. Many such clusters ? the blue regions ? as well as looser associations of massive stars, can be seen in this image. The large number of massive stars in NGC 2403 leads to a high supernova rate. Two other supernovae have been seen in this galaxy during the past half-century.

The heart of NGC 2403 is the glowing region at lower left. Sprinkled across the region are pink areas of star birth. The myriad of faint stars visible in the Hubble image belong to NGC 2403, but the handful of very bright stars in the image belong to our own Milky Way Galaxy and are only a few hundred to a few thousand light-years away. This image was taken on Aug. 17, two weeks after an amateur astronomer discovered the supernova.

Japanese amateur astronomer Koichi Itagaki discovered the supernova on July 31, 2004, with a small telescope. Additional observations soon showed that it is a “Type II supernova,” resulting from the explosion of a massive, hydrogen-rich star at the end of its life. The cataclysm probably occurred when the evolved star’s central core, consisting of iron, suddenly collapsed to form an extremely dense object called a neutron star. The surrounding layers of gas bounced off the neutron star and also gained energy from the flood of ghostly “neutrinos” (tiny, almost non-interacting particles) that may have been released, thereby violently expelling these layers.

This explosion is ejecting heavy chemical elements, generated by nuclear reactions inside the star, into the cosmos. Like other Type II supernovae, this exploding star is providing the raw material for future generations of stars and planets. Elements on Earth such as oxygen, calcium, iron, and gold came long ago from exploding stars such as this one.

Astronomers will continue to study SN 2004dj over the next few years, as it slowly fades from view, in order to gain a better understanding of how certain types of stars explode and what kinds of chemical elements they eject into space.

This color-composite photograph was obtained by combining images through several filters taken with the Wide Field Camera of the Advanced Camera for Surveys. The colors in the image highlight important features in the galaxy. Hot, young stars are blue. Older stars and dense dust lanes near the heart of the galaxy are red. The hydrogen-rich, star-forming regions are pink. The dense concentration of older stars in the galaxy’s central bulge is yellow.

In addition to the visible-light image shown here, ultraviolet images and spectra are being obtained with Hubble’s Advanced Camera for Surveys. Astronomers are also using ground-based telescopes to study the supernova.

Original Source: Hubble News Release

Posted on by Fraser Cain

NASA Readies for Hurricane Frances

NASA is keeping a close watch over Hurricane Frances as it churns toward the United States. International Space Station cameras are capturing spectacular images of the storm from above. On the Florida coast, NASA’s Kennedy Space Center (KSC) is making preparations to protect the Space Shuttle fleet, spacecraft hardware, and facilities against damage.

Video of Hurricane Frances taken by external television cameras aboard the Space Station at about 7:30 a.m. EDT today vividly depicts a classically shaped storm in the Atlantic Ocean. The video, along with additional views captured during the weekend, is airing on the NASA TV Video File throughout the day. NASA will release new footage of Frances as it becomes available.

NASA also has still images of the storm, taken by Astronaut Mike Fincke aboard the International Space Station, as well as NASA’s Terra satellite. They’re available at:

http://www.nasa.gov/vision/earth/lookingatearth/frances.html

At KSC, workers are powering down the Space Shuttle orbiters, closing their payload bay doors and stowing their landing gear. They are also taking precautions against flooding by moving spacecraft hardware off the ground and sandbagging facilities. NASA plans to release video of these activities beginning tomorrow.

NASA TV is available on the Web and via satellite, in the continental U.S. on AMC-6, Transponder 9C, C-Band, located at 72 degrees west longitude. The frequency is 3880.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz. In Alaska and Hawaii, NASA TV is available on AMC-7, Transponder 18C, C-Band, located at 137 degrees west longitude. Frequency is 4060.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz.

Original Source: NASA News Release

Posted on by Fraser Cain

Atlas Launches Secret Payload

An Atlas IIAS rocket lifted off tonight, successfully carrying a national security payload into orbit.

The mission, called AC-167, was provided for the National Reconnaissance Office (NRO) by International Launch Services (ILS), using a Lockheed Martin-built Atlas vehicle. Liftoff was at 7:17 p.m. Tuesday EDT (23:17 today GMT) from Cape Canaveral?s Pad 36A, with payload separation into transfer orbit 73 minutes later.

Tonight?s flight was the eighth mission of the year for ILS, as well as the fifth Atlas launch. It also was the 73rd consecutive successful flight for the Atlas family in any launch configuration. This also marks the 30th and final flight for an Atlas IIAS model and the 63rd flight and final flight of any Atlas II version. In addition, this was the final flight after 47 years of the Rocketdyne MA-5A engine, which powered the Atlas II booster.

?The Atlas family has launched government payloads for more than 40 years,? said ILS President Mark Albrecht. ?We?re always proud to have a role in assisting in the security of our nation.?

Albrecht also pointed out the perfect record of not only the Atlas IIAS vehicles, but of the entire Atlas II line, which began flying in December 1991. ?This is an awesome accomplishment, being the only U.S. expendable launch vehicle series to have had 100 percent success throughout its entire lifespan,? he said. ?The Atlas team is an incredible group of people who make Mission Success for our customers a way of life.?

This is the second ILS launch this month, following the Aug. 5 successful flight of a Proton Breeze M vehicle, with the Amazonas satellite for Hispasat of Spain and Hispamar of Brazil.

ILS is a joint venture of Atlas builder Lockheed Martin and the Proton?s builder, Khrunichev State Research and Production Space Center of Russia. ILS is headquartered in McLean, Va., a suburb of Washington, D.C.

ILS has established itself as the indisputable launch services leader by offering the industry’s two best launch systems: Atlas and Proton. With a remarkable launch rate of 66 missions since 2000, the Atlas and Proton launch vehicles have consistently demonstrated the reliability and flexibility that have made them the vehicles of choice. Since the beginning of 2003, ILS has signed more new commercial contracts than all its competitors combined. For more information and highlights of the mission, visit www.ilslaunch.com.

Original Source: ILS News Release

Posted on by Fraser Cain

Arriving This Week: The Ozone Hole

Image credit: ESA
The smudges of dark blue on this Envisat-derived ozone forecast trace the start of what has unfortunately become an annual event: the opening of the ozone hole above the South Pole.

“Ever since this phenomenon was first discovered in the mid-1980s, satellites have served as an important means of monitoring it,” explained Jos? Achache, ESA Director of Earth Observation Programmes. “ESA satellites have been routinely observing stratospheric ozone concentrations for the last decade.

“And because Envisat’s observations are assimilated into atmospheric models, they actually serve as the basis of an operational ozone forecasting service. These models predict the ozone hole is in the process of opening this week.”

Envisat data show 2004’s ozone hole is appearing about two weeks later than last year’s, but at a similar time period to the average during the last decade. The precise time and range of Antarctic ozone hole occurrences are determined by regional meteorological variations.

The ozone hole typically persists until November or December, when increasing regional temperatures cause the winds surrounding the South Pole to weaken, and ozone-poor air inside the vortex is mixed with ozone-rich air outside it.

The ozone hole of 2002 was an exception to this general pattern, when a late September slowdown of the polar vortex caused the ozone hole to split in two and dissipate early. Envisat’s predecessor mission, ERS-2, monitored the process.

“Envisat carries an instrument called the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY), based on a previous instrument flown aboard ERS-2, called the Global Ozone Monitoring Experiment (GOME),” said Henk Eskes of the Royal Netherlands Meteorological Institute (KNMI). “The two instruments give us a combined data set that stretches over ten years, one that Envisat adds to every day with fresh observations.

“This data set presents a very good means of eventually identifying long-term trends in ozone. Whether or not the ozone layer is starting to recover is a hotly debated topic at the moment.”

The stratospheric ozone layer protects life on Earth from harmful ultraviolet (UV) radiation. The ozone thinning represented here is ultimately caused by the presence of man-made pollutants in the atmosphere such as chlorine, originating from man-made pollutants like chlorofluorocarbons (CFCs).

Now banned under the Montreal Protocol, CFCs were once widely used in aerosol cans and refrigerators. CFCs themselves are inert, but ultraviolet radiation high in the atmosphere breaks them down into their constituent parts, which can be highly reactive with ozone.

Just because they were banned does not mean these long-lived chemicals have vanished from the air, so scientists expect the annual South Polar ozone hole to continue to appear for many years to come.

During the southern hemisphere winter, the atmospheric mass above the Antarctic continent is kept cut off from exchanges with mid-latitude air by prevailing winds known as the polar vortex. This leads to very low temperatures, and in the cold and continuous darkness of this season, polar stratospheric clouds are formed that contain chlorine.

As the polar spring arrives, the combination of returning sunlight and the presence of polar stratospheric clouds leads to splitting of chlorine into highly ozone-reactive radicals that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.

ESA’s ten-instrument Envisat spacecraft carries three instruments to measure the atmosphere; the results here come from SCIAMACHY, which provides global coverage of the distribution of ozone and other trace gases, as well as aerosols and clouds.

KNMI processes SCIAMACHY data in near-real time as the basis of an operational ozone forecasting service. This is part of a suite of atmospheric information services provided by a project called TEMIS (Tropospheric Emission Monitoring Internet Service) that also includes UV radiation monitoring and forecasting.

TEMIS is backed by ESA as part of the Agency’s Data User Programme, intended to establish viable Earth Observation-based services for communities of users.

The TEMIS atmospheric ozone forecast seen here has atmospheric ozone measured in Dobson Units (DUs), which stands for the total thickness of ozone in a given vertical column if it were concentrated into a single slab at standard temperature and atmospheric pressure ? 400 DUs is equivalent to a thickness of four millimetres, for example.

Envisat results to be revealed
Launched in March 2002, ESA’s Envisat satellite is an extremely powerful means of monitoring the state of our world and the impact of human activities upon it. Envisat carries ten sophisticated optical and radar instruments to observe and monitor the Earth’s atmosphere, land, oceans and ice caps, maintaining continuity with the Agency’s ERS missions started in 1991.

After two and a half years in orbit, more than 700 scientists from 50 countries are about to meet at a special symposium in Salzburg in Austria to review and discuss early results from the satellites, and present their own research activities based on Envisat data.

Starting next Monday, the Envisat Symposium will address almost all fields of Earth science, including atmospheric chemistry, coastal studies, radar and interferometry, winds and waves, vegetation and agriculture, landslides, natural risks, air pollution, ocean colour, oil spills and ice.

There are over 650 being presented at the Symposium, selected by peer review. Presentations will include results on the Prestige oil spill, last year’s forest fires in Portugal, the Elbe flooding in 2002, the evolution of the Antarctic ozone hole, the Bam earthquake and pollution in Europe.

Numerous demonstrations are planned during the week in the ESA Exhibit area. An industrial consortium exhibit on the joint ESA-European Commission Global Monitoring for Environment and Security (GMES) initiative is also planned.

Original Source: ESA News Release

Posted on by Fraser Cain

Astronomer Fred Whipple Dies

Dr. Fred Lawrence Whipple, the oldest living American astronomer and one of the last giants of 20th century astronomy, passed away yesterday at the age of 97 following a prolonged illness. He was Phillips Professor of Astronomy Emeritus at Harvard University and a Senior Physicist at SAO.

“Fred Whipple was one of those rare individuals who affected our lives in many ways. He predicted the coming age of satellites, he revolutionized the study of comets and as Director of the Smithsonian Astrophysical Observatory, he helped form the Harvard-Smithsonian Center for Astrophysics,” says Charles Alcock, current Director of the Harvard-Smithsonian Center for Astrophysics (CfA).

A discoverer of six comets, Whipple may be best known for his comet research. Five decades ago, he first suggested that comets were “icy conglomerates,” what the press called “dirty snowballs.” His dirty snowball theory caught the imagination of the public even as it revolutionized comet science.

Whipple’s change of concept from the generally accepted “flying sandbank” model was “one of the most important contributions to solar system studies in the 20th century,” says Dr. Brian Marsden, director of the Minor Planet Center located at SAO. “I think many people would agree that that was a really shining moment in his scientific career.” A 2003 survey by The Astrophysical Journal showed that Whipple’s 1950 and 1951 scientific papers on the “icy conglomerate” model were the most cited papers in past 50 years.

Whipple’s comet work continued for a lifetime. In 1999, he was named to work on NASA’s Contour mission, becoming the oldest researcher ever to accept such a post.

Never one to limit his work to one area of research, Whipple also contributed to more earthly challenges. During World War II, Whipple co-invented a cutting device that converted lumps of tinfoil into thousands of fragments known as chaff. Allied aircraft would release chaff to confuse enemy radar. Whipple was particularly proud of this invention, for which President Truman awarded him a Certificate of Merit in 1948.

Whipple also strongly influenced the early era of spaceflight. Mindful of the damage to spacecraft from meteors, in 1946 he invented the Meteor Bumper, a thin outer skin of metal. Also known as the Whipple Shield, this mechanism explodes a meteor on contact, preventing the spacecraft from receiving catastrophic damage. Improved versions of it are still in use today.

Whipple and a handful of other scientists had the foresight to envision the era of artificial satellites. Only Whipple had both the imagination and the managerial skill to organize a worldwide network of amateur astronomers to track these then hypothetical objects and to determine their orbits. When Sputnik I was successfully launched on 4 October 1957, Whipple’s group was the only one prepared. Cambridge fast became a nerve center of the earliest part of the space age. Whipple and some of his staff were even featured on the cover of Life magazine for their satellite tracking prowess.

Later, also under his leadership, SAO developed an optical tracking system for satellites using a network of Baker-Nunn cameras. That network achieved spectacular success. “It tracked satellites so well that astronomers were able to determine the exact shape of the Earth from its gravitational effects on satellite orbits,” says Dr. Myron Lecar of SAO.

For his work on the network, Whipple received from President John F. Kennedy in 1963 the Distinguished Federal Civilian Service award. “I think that was my most exciting moment, when I was able to invite my parents and my family to the Rose Garden for the award ceremony,” Whipple said in a 2001 interview.

Born in Red Oak, Iowa, on November 5, 1906, Whipple studied at Occidental College and earned his undergraduate degree in mathematics at the University of California at Los Angeles, prior to moving to Berkeley to obtain his Ph.D. degree in 1931. He then moved to Harvard College Observatory in Cambridge, Massachusetts.

Whipple directed the Smithsonian Astrophysical Observatory (SAO) from 1955 to 1973, before it joined with the Harvard College Observatory to form the Harvard-Smithsonian Center for Astrophysics (CfA).

“Fred Whipple was a truly extraordinary person among extraordinary people. He was gifted with great scientific imagination, superb analytical skills, and excellent management acumen,” says Dr. Irwin Shapiro, who served as CfA director from 1983 to 2004.

In the late 1960s, Whipple selected Mount Hopkins in southern Arizona as the site for a new SAO astronomical facility. Whipple was part of the group that initiated a novel and low-cost approach to building large telescopes first realized in the construction of the Multiple Mirror Telescope, a joint project of SAO and the University of Arizona. Mt. Hopkins Observatory was renamed Fred Lawrence Whipple Observatory in 1981.

Dr. George Field, the first CfA director, says of Whipple, “He will be remembered by a generation of scientists for his leadership and for his keen insight. He was admired by his friends and colleagues for his integrity, and for doggedly pursuing his research into his nineties.”

In 1946 Whipple married Babette F. Samelson, by whom he had two daughters, Sandra and Laura. He also had a son, Earle Raymond, by his first marriage.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Original Source: Harvard-Smithsonian Center for Astrophysics News Release