Posted on by Fraser Cain

New Shuttle Solid Rocket Booster Tested

Image credit: Blake Goddard

Alliant Techsystems performed the first static test of a new five-segment solid rocket booster for the space shuttle. This new booster gives approximately 10% more thrust than the four-segment boosters that the shuttle currently flies with. If these new boosters are installed on the shuttle it would have a few benefits: the shuttle would have enough thrust to still reach orbit if its main engine fails, it won’t have to make an emergency landing; or it could be used to let the shuttle carry an additional 10,500 kg of cargo.

ATK (Alliant Techsystems, NYSE: ATK) yesterday successfully conducted the first static test firing of a five-segment Space Shuttle reusable solid rocket motor (RSRM).

The test conducted by ATK Thiokol Propulsion, Promontory, Utah, was part of an ongoing safety program to verify materials and manufacturing processes, by ground testing motors with specific test objectives. This five-segment motor, also considered a margin test motor, pushed various features of the motor to its limits so engineers could validate the safety margins of the four-segment motor currently used to launch Space Shuttles. The static firing was also a test designed to demonstrate the ability of the five-segment motor to perform at thrust levels in excess of 3.6 million pounds, approximately 10 percent greater than the four-segment motor.

?This test demonstrated ATK?s unique ability and expertise in the design and production of the RSRM,? said Jeff Foote, group vice president, Aerospace. ?It is yet another visible commitment by NASA and ATK to ensure the highest quality safety standards and mission success for future Space Shuttle flights.?

Foote said that in addition to validating safety margins by over-testing many RSRM attributes, the static firing also demonstrated the capability of the five-segment motor to increase Space Shuttle payload capacity by 23,000 pounds, or enable a safe abort to orbit in the event of loss of thrust from the main engines.

The five-segment motor generated an average thrust of 3.1 million pounds and burned for approximately 128 seconds. The current four-segment configuration generates an average 2.6 million pounds of thrust and burns for approximately 123 seconds. The new motor measures 12 feet in diameter and is 153.5 feet long ? 27.5 feet longer than the four-segment motor.

The static test allowed ATK to verify and validate numerous performance characteristics, processes, materials, components, and design changes that were incorporated into the five-segment RSRM. The test had 67 objectives and employed 633 instrumentation channels to collect data for evaluation. Preliminary results indicate that the motor met or exceeded all objectives.

The Space Shuttle RSRM is the largest solid rocket motor ever flown and the first designed for reuse. The reusability of the RSRM case and nozzle hardware is an important cost-saving factor for the nation’s space program. Each Space Shuttle launch currently requires the boost of two RSRMs. By the time the twin RSRMs have completed their task, the Space Shuttle orbiter has reached an altitude of 24 nautical miles and is traveling at a speed in excess of 3,000 miles per hour.

ATK Thiokol Propulsion is the world?s leading supplier of solid-propellant rocket motors. Products manufactured by the company include propulsion systems for the Delta, Pegasus?, Taurus?, Athena, Atlas, H-IIA, and Titan IV B expendable space launch vehicles, NASA?s Space Shuttle, the Trident II Fleet Ballistic Missile and the Minuteman III Intercontinental Ballistic Missile, and ground-based missile defense interceptors.

ATK is a $2.2 billion aerospace and defense company with strong positions in propulsion, composite structures, munitions, precision capabilities, and civil and sporting ammunition. The company, which is headquartered in Edina, Minn., employs approximately 12,200 people and has three business groups: Precision Systems, Aerospace, and Ammunition and Related Products. ATK news and information can be found on the Internet at www.atk.com.

Original Source: Alliant News Release

Posted on by Fraser Cain

Shrinking Arctic Sea Ice is Accelerating

Image credit: NASA

New images of shrinking sea ice may provide further evidence that the Earth is undergoing significant climate change. NASA scientists compared images of arctic sea ice since 1981 and have measured that it’s shrinking by an average of 9% per decade – summer sea ice in 2002 was a record low levels. The loss of ice could accelerate global warming because liquid water absorbs sunlight instead of reflecting it like ice.

Recently observed change in Arctic temperatures and sea ice cover may be a harbinger of global climate changes to come, according to a recent NASA study. Satellite data — the unique view from space — are allowing researchers to more clearly see Arctic changes and develop an improved understanding of the possible effect on climate worldwide.

The Arctic warming study, appearing in the November 1 issue of the American Meteorological Society’s Journal of Climate, shows that compared to the 1980s, most of the Arctic warmed significantly over the last decade, with the biggest temperature increases occurring over North America.

“The new study is unique in that, previously, similar studies made use of data from very few points scattered in various parts of the Arctic region,” said the study’s author, Dr. Josefino C. Comiso, senior research scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md. “These results show the large spatial variability in the trends that only satellite data can provide.” Comiso used surface temperatures taken from satellites between 1981 and 2001 in his study.

The result has direct connections to NASA-funded studies conducted last year that found perennial, or year-round, sea ice in the Arctic is declining at a rate of nine percent per decade and that in 2002 summer sea ice was at record low levels. Early results indicate this persisted in 2003.

Researchers have suspected loss of Arctic sea ice may be caused by changing atmospheric pressure patterns over the Arctic that move sea ice around, and by warming Arctic temperatures that result from greenhouse gas buildup in the atmosphere.

Warming trends like those found in these studies could greatly affect ocean processes, which, in turn, impact Arctic and global climate, said Michael Steele, senior oceanographer at the University of Washington, Seattle. Liquid water absorbs the Sun’s energy rather than reflecting it into the atmosphere the way ice does. As the oceans warm and ice thins, more solar energy is absorbed by the water, creating positive feedbacks that lead to further melting. Such dynamics can change the temperature of ocean layers, impact ocean circulation and salinity, change marine habitats, and widen shipping lanes, Steele said.

In related NASA-funded research that observes perennial sea-ice trends, Mark C. Serreze, a scientist at the University of Colorado, Boulder, found that in 2002 the extent of Arctic summer sea ice reached the lowest level in the satellite record, suggesting this is part of a trend. “It appears that the summer 2003 — if it does not set a new record — will be very close to the levels of last year,” Serreze said. “In other words, we have not seen a recovery; we really see we are reinforcing that general downward trend.” A paper on this topic is forthcoming.

According to Comiso’s study, when compared to longer term ground-based surface temperature data, the rate of warming in the Arctic over the last 20 years is eight times the rate of warming over the last 100 years.

Comiso’s study also finds temperature trends vary by region and season. While warming is prevalent over most of the Arctic, some areas, such as Greenland, appear to be cooling. Springtimes arrived earlier and were warmer, and warmer autumns lasted longer, the study found. Most importantly, temperatures increased on average by 1.22 degrees Celsius per decade over sea ice during Arctic summer. The summer warming and lengthened melt season appears to be affecting the volume and extent of permanent sea ice. Annual trends, which were not quite as strong, ranged from a warming of 1.06 degrees Celsius over North America to a cooling of .09 degrees Celsius in Greenland.

If the high latitudes warm, and sea ice extent declines, thawing Arctic soils may release significant amounts of carbon dioxide and methane now trapped in permafrost, and slightly warmer ocean water could release frozen natural gases in the sea floor, all of which act as greenhouse gases in the atmosphere, said David Rind, a senior researcher at NASA’s Goddard Institute of Space Studies, New York. “These feedbacks are complex and we are working to understand them,” he added.

The surface temperature records covering from 1981 to 2001 were obtained through thermal infrared data from National Oceanic and Atmospheric Administration satellites. The studies were funded by NASA’s Earth Science Enterprise, which is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather and natural hazards using the unique vantage point of space.

Original Source: NASA News Release

Posted on by Fraser Cain

Big Solar Storm Headed our Way

Image credit: SOHO

A gigantic group of sunspots, 10 times larger than the Earth, have been active on the surface of the Sun for the past few days. Solar astronomers have spotted several Coronal Mass Ejections (CMEs) blasting out of the sunspots, and one of them seems to be coming our way. Once it reaches the Earth, it will interact with the planet’s geomagnetic field, and potentially disrupt communications satellites. Beautiful auroras (Northern Lights) will probably be visible, even from middle latitudes. The solar material is expected to sweep past the Earth Friday or Saturday.

Forecasters at the NOAA Space Environment Center in Boulder, Colo., observed two dynamic areas of the sun, one of which has produced a coronal mass ejection, or CME, Wednesday morning at 3 a.m. EDT that appears to be Earth-directed. The forecasters are predicting a strong geomagnetic storm, G-3 on the NOAA Space Weather Scales, that should reach Earth on Friday, October 24. (Click here to view larger image from the SOHO spacecraft of the intense solar activity on the sun taken Oct. 21, 2003. Click here to view high resolution version, which is a large file. Click here to view latest images. Please credit ?SOHO.?)

NOAA Region 484 developed rapidly over the past three days and is now one of the largest sunspot clusters to emerge during Solar Cycle 23. It is about 10 times larger than the Earth. This region, which is nearing the center of the sun, already produced a major flare, R-3 on the NOAA Space Weather Scales, producing a radio blackout on October 19 at 12:50 p.m EDT. The region continues to grow, and additional substantial flare activity is likely.

Larry Combs, a forecaster with the NOAA Space Environment Center?s Space Weather Operations, said that this region has developed rapidly over the last three to four days. ?It?s somewhat unusual to have this much activity when we?re approximately three-and-a-half years past solar maximum,? he said. ?In fact, just last week, solar activity was very low with an almost spotless sun.? Solar cycles of high and low activity repeat about every eleven years, and the sun has been moving towards solar minimum for the past three years.

A second intense active region is rotating on the southeast quadrant of the sun. Although the sunspot group is not yet visible, two powerful eruptions occurred on October 21 as seen from the LASCO instrument on the SOHO spacecraft. These eruptions may herald the arrival of another volatile active center with the potential to impact various Earth systems.

Further major eruptions are possible from these active regions as they rotate across the face of the sun over the next two weeks. Satellite and other spacecraft operations, power systems, high frequency communications, and navigation systems may experience disruptions over this two-week period.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation?s coastal and marine resources. NOAA is part of the U.S. Department of Commerce.

Original Source: NOAA News Release

Posted on by Fraser Cain

Cosmic Ray Detector Completed

Image credit: Fermilab

The 100th detector for the Pierre Auger Observatory was recently completed, making the array the world’s largest cosmic ray detector. It consists of surface detectors spread out over 181 square kilometers of land in Argentina. Once it’s working, the detector should be able to capture some of the most energetic cosmic ray particles – they only strike a 2.5 square kilometer area once a year. The mystery with these high-energy particles is that astronomers have no idea what in the Universe could create them. The long term plans for the observatory is to eventually have 1,600 detectors by 2005.

With the completion of its hundredth surface detector, the Pierre Auger Observatory, under construction in Argentina, this week became the largest cosmic-ray air shower array in the world. Managed by scientists at the Department of Energy’s Fermi National Accelerator Laboratory, the Pierre Auger project so far encompasses a 70-square-mile array of detectors that are tracking the most violent-and perhaps most puzzling- processes in the entire universe.

Cosmic rays are extraterrestrial particles-usually protons or heavier ions-that hit the Earth’s atmosphere and create cascades of secondary particles. While cosmic rays approach the earth at a range of energies, scientists long believed that their energy could not exceed 1020 electron volts, some 100 million times the proton energy achievable in Fermilab’s Tevatron, the most powerful particle accelerator in the world. But recent experiments in Japan and Utah have detected a few such ultrahigh energy cosmic rays, raising questions about what extraordinary events in the universe could have produced them.

“How does nature create the conditions to accelerate a tiny particle to such an energy?” asked Alan Watson, physics professor at the University of Leeds, UK, and spokesperson for the Pierre Auger collaboration of 250 scientists from 14 countries. “Tracking these ultrahigh-energy particles back to their sources will answer that question.”

Scientific theory can account for the sources of low- and medium-energy cosmic rays, but the origin of these rare high-energy cosmic rays remains a mystery. To identify the cosmic mechanisms that produce microscopic particles at macroscopic energy, the Pierre Auger collaboration is installing an array that will ultimately comprise 1,600 surface detectors in an area of the Argentine Pampa Amarilla the size of Rhode Island, near the town of Malarg?e, about 600 miles west of Buenos Aires. The first 100 detectors are already surveying the southern sky.

“These highest-energy cosmic rays are messengers from the extreme universe,” said Nobel Prize winner Jim Cronin, of the University of Chicago, who conceived the Auger experiment together with Watson. “They represent a great opportunity for discoveries.”

The highest-energy cosmic rays are extremely rare, hitting the Earth’s atmosphere about once per year per square mile. When complete in 2005, the Pierre Auger observatory will cover approximately 1,200 square miles (3,000 square kilometers), allowing scientists to catch many of these events.

“Our experiment will pick up where the AGASA experiment has left off,” said project manager Paul Mantsch, Fermilab, referring to the Akeno Giant Air Shower Array (AGASA) experiment in Japan. “At highest energies, the astonishing results from the two largest cosmic-ray experiments appear to be in conflict. AGASA sees more events than the HiRes experiment in Utah, but the statistics of both experiments are limited.”

The Pierre Auger project, named after the pioneering French physicist who first observed extended air showers in 1938, combines the detection methods used in the Japanese and Utah experiments. Surface detectors are spaced one mile apart. Each surface unit consists of a 4-foot-high cylindrical tank filled with 3,000 gallons of pure water, a solar panel, and an antenna for wireless transmission of data. Sensors register the invisible particle avalanches, triggered at an altitude of six to twelve miles just microseconds earlier, as they reach the ground. The particle showers strike several tanks almost simultaneously.

In addition to the tanks, the new observatory will feature 24 HiRes-type fluorescence telescopes that can pick up the faint ultraviolet glow emitted by air showers in mid-air. The fluorescence telescopes, which can only be operated during dark, moonless nights, are sensitive enough to pick up the light emitted by a 4-watt lamp traveling six miles away at almost the speed of light.

“It is a really beautiful thing that we have a hybrid system,” said Watson. “We can look at air showers in two modes. We can measure their energy in two independent ways.”

The Pierre Auger collaboration is in the process of preparing a proposal for a second site of its observatory, to be located in the United States. Featuring the same design as the Argentinean site, the second detector array would scan the northern sky for the sources of the most powerful cosmic rays.

Funding for the $55 million Pierre Auger Observatory in Argentina has come from 14 member nations. The U.S. contributes 20 percent of the total cost, with support provided by the Office of Science of the Department of Energy and by the National Science Foundation. A list of all participating institutions is available at http://auger.cnrs.fr/collaboration.html

Fermilab is a national laboratory funded by the Office of Science of the U.S. Department of Energy, operated by Universities Research Association, Inc.

Original Source: Fermilab News Release

Posted on by Fraser Cain

Crew Launched Despite Station Concerns

NASA’s latest launch to the International Space Station wasn’t without controversy. The Washington Post is reporting that two officials responsible for health and environmental conditions on the station refused to approve the launch of the new crew. Instead they warned that critical components on the station had degraded and could risk the health and safety of the astronaut crew. NASA says it’s aware of the problem, but doesn’t consider it to be an immediate threat. Without the space shuttle to repair and upgrade the station, they could be forced to abandon it within six months.

Posted on by Fraser Cain

Total Lunar Eclipse – November 8-9, 2003

Image credit: NASA

Mark your calendars for an astronomical event that you don’t want to miss. In the early morning of Sunday, November 9, most of the Western Hemisphere and Europe will be treated to a total lunar eclipse. And Universe Today is going to be gathering together a network of astrocameras, so you can watch it on the Internet if the weather doesn’t cooperate for you.

Mark your calendars for an astronomical event that you don’t want to miss. In the early morning of Sunday, November 9, most of the Western Hemisphere and Europe will be treated to a total lunar eclipse. And Universe Today is going to be gathering together a network of astrocameras, so you can watch it on the Internet if the weather doesn’t cooperate for you.

First a little background. Lunar eclipses happen once or twice a year when the Moon, Earth and Sun are lined up so well that the Moon passes into the Earth’s shadow. Over the course of a few hours, the Moon darkens, until it’s fully obscured and then turns a deep red colour. Unlike a solar eclipse, a lunar eclipse is perfectly safe to watch with your unprotected eyes; it’s no brighter than looking at the full Moon.

The eclipse will begin on November 8 at 2215 GMT, but the Moon won’t actually seem any darker until about an hour later. It’ll be fully obscured on November 9 at 0119 GMT, and then brighten again by 0305 GMT.

The whole event will be visible to people in the Americas, Europe and Africa, but not at all visible to Asia and Australia. For people on the West Coast of the Americas, the eclipse will have already begun when the Moon rises above the horizon, and for people closer to Asia, the Moon will be set before the eclipse is complete. For example, in Seattle, Washington, the Moon will already be 13% eclipsed when it rises.

Here’s a detailed table of times for different timezones:

  PST CST EST GMT
Visible Eclipse Begins N/A Nov 8 – 5:32 pm Nov 8 – 6:32 pm Nov 8 – 23:32
Maximum Eclipse Nov 8 – 5:19 pm Nov 8 – 7:19 pm Nov 8 – 8:19 pm Nov 9 – 01:19
Visible Eclipse Ends Nov 8 – 7:05 pm Nov 8 – 9:05 pm Nov 8 – 10:05 pm Nov 9 – 03:05

As usual, Universe Today will be showcasing astrocameras from around the area providing coverage of the eclipse. If you’re outside the visible area, or the weather doesn’t cooperate for you (November in Vancouver = rain), then you can enjoy it live from the comfort of your computer. If you’d like to get involved, please send me an email at [email protected].

This will be the second lunar eclipse for 2003; the first happened back in May, and was visible from similar regions on the Earth. The next total lunar eclipse will be visible from Europe and Asia on May 4, 2004.

Posted on by Fraser Cain

Long-Lost Asteroid Re-Discovered

Image credit: Lowell Observatory

Astronomers from the Lowell Observatory have re-discovered a Near Earth Asteroid that hasn’t been seen since 1937. The object is called Hermes and it was originally discovered by German astronomer Karl Reinmuth; a few days later it was out of sight, and astronomers didn’t have enough information about its orbit to locate it again. With the new observations, astronomers believe that Hermes is actually a binary object; it has its own small moon.

The re-discovery of Hermes started early on October 15th by Brian Skiff of the Lowell Observatory Near-Earth-Object Search (LONEOS). Not seen since 1937, asteroid 1937 UB (Hermes) continues to astonish and excite astronomers worldwide. Further observations revealed late yesterday that Hermes is actually two objects–called a binary–circling around one another while about to pass by Earth again.

“This re-sighting of Hermes is the Holy Grail of near-Earth asteroid discovery,” said Edward Bowell, LONEOS Director. “Its orbit has been better calculated and observers have confirmed its re-appearance and also shown its binary nature? well, an asteroid?s return just does not become more profound than this.”

The binary object was some 19 million miles out at the time of re-discovery last Wednesday, nearly 66 years after it was first seen. Hermes, which poses no threat to Earth, will make its closest approach on November 4th. By then it will be 4 million miles away and bright enough for amateurs to see using backyard telescopes.

The same day Skiff captured the first images of Hermes, Discovery Communications, Inc. and Lowell Observatory announced a partnership to build the new Discovery Channel Telescope near Flagstaff, Arizona (http://www.lowell.edu/press_room/releases/recent_releases/dct_rls.html). One research objective for this new $30-million, 4.3-meter telescope will be to significantly accelerate the search for near-Earth objects, including those smaller than Hermes.

First images of the kilometer-size asteroid were captured by a CCD camera during early morning observation through the LONEOS 24-inch Schmidt telescope. More than six decades ago, Hermes was discovered by Karl Reinmuth at Heidelberg, Germany on October 25, 1937. Fast forward to a few days ago when Andrea Boattini of Instituto di Astrofisica Spaziale, Rome, Italy, and Timothy Spahr of the Minor Planet Center in Cambridge, Massachusetts analyzed the new positions of Hermes and determined what it was: the long-lost asteroid.

“Since we find new near-Earth asteroids fairly regularly (I found, for instance, two near-Earth asteroids the same night), my only reaction upon finding it was that it was unusually bright,” Skiff told BBC News Online on Friday.

Up before dawn, Spahr quickly posted Skiff?s discovery on the web, alerting astronomers to follow the asteroid. James Young, at the Jet Propulsion Laboratory?s Table Mountain Observatory in California, was the first to respond, just five hours later. Spahr then located observations made on October 5 by the Near-Earth Asteroid Tracking program (http://neat.jpl.nasa.gov), LONEOS observations from September 28, and unpublished observations made by the MIT Lincoln Laboratory Near Earth Asteroid Research program (http://www.ll.mit.edu/LINEAR), extending the observational arc back to August 26 (http://cfa-www.harvard.edu/mpec/K03/K03T74.html).

At this point, the identification with Hermes was clear from the similarity of the orbits from the 1937 and 2003 sightings, but it was not a simple matter to compute an orbit that linked all the observations together. Steven Chesley and Paul Chodas of the Jet Propulsion Laboratory found that Hermes? trajectory is very chaotic due to frequent close encounters with the Earth and Venus. Following its flyby of the Earth in 1937 at a distance of 460,000 miles (just 1.8 times the Moon?s distance), Hermes made an unobserved close approach to the Earth in 1942 of just 1.6 lunar distance. Using JPL?s Sentry impact monitoring software, Chesley and Chodas were able to find 12 distinct dynamical pathways that produced an encounter in 1937. Picking out the true orbit was then an easy matter, and led to the further prediction that Hermes will not approach the Earth more closely than 8 lunar distances within the next century (http://neo.jpl.nasa.gov/news/news140.html).

On October 16, Andrew Rivkin and Richard Binzel of MIT observed a spectrum of Hermes using the NASA Infrared Telescope Facility in Hawaii, and were able to ascertain that the asteroid is of a type known as S class. Because the surfaces of S-class asteroids reflect, on average, 24% of the sunlight falling on them, Rivkin and Binzel were able to deduce that Hermes is 0.9 km (about 1,000 yards) in diameter.

Over the next few days, the world?s most powerful radar, the 1,000-foot dish, at Arecibo, Puerto Rico, projected radar beams on to the asteroid and captured the faint returning echoes. Jean-Luc Margot, of the University of California, Los Angeles, and his team saw that the asteroid is strongly bifurcated. Two separate components, of roughly equal size and almost in contact, are revolving about their common center of mass in up to 21 hours. It appears that the components have tidally evolved into a situation where their spin period is equal to their orbital period and therefore present the same face to one another all the time, just like the Pluto-Charon system. There are now about 10 radar-observed binary near-Earth asteroids, about 1 in 6 of NEAs larger than 200 m in diameter. “We certainly did not expect to find a binary with roughly equal-sized components,” said Margot. “All the binary NEAs that we have imaged so far show a secondary that is only a fraction of the size of the primary.”

Amateur and professional astronomers are collaborating to observe the way Hermes changes in brightness as its components rotate. Eventually, they should be able to determine the components? orbital plane, an accurate period of revolution, and, perhaps, the shapes of the individual bodies. See http://www.asu.cas.cz/~asteroid/binneas.htm for a list of binary NEAs.

The only near-Earth object not also identified by number, Hermes shares a name in Greek mythology with the son of Zeus, messenger of the gods, god of science, commerce, eloquence, and arts of life. “The name ?Hermes? also means hastener, and representations of him are symbolic of the messenger or the speed and majesty in flight,” according to Schmadel?s Dictionary of Minor Planet Names.

Lowell Observatory was founded in 1894 by Percival Lowell with a mission to pursue the study of astronomy, especially the study of our Solar System and its evolution; to conduct pure research in astronomical phenomena; and to maintain quality public education and outreach programs to bring results of astronomical research to the general public. Visit http://www.lowell.edu; and Friends of Lowell at http://www.lowell.edu/friends/.

LONEOS is one of five programs funded by NASA to search for asteroids and comets that may approach our planet closely. Their current goal is to discover 90% of near-Earth asteroids larger than 1 km in diameter by 2008. There are thought to be about 1,200 such asteroids.

For more information on the discovery and images of Hermes, visit the LONEOS website at http://asteroid.lowell.edu/asteroid/loneos/loneos.html.

Original Source: Lowell Observatory News Release

Posted on by Fraser Cain

Learning How Planets Form

Astronomers are hoping NASA’s new Space Infrared Telescope Facility will answer more questions about how disks of gas and dust turn into a planetary system. The problem is that the disk seems to get obscured by material during the middle stages of its formation. SIRTF should be able to peer through the obscuring material to reveal this missing link of planetary formation. At some point in the system’s evolution, mass is eaten up by the star, ejected into space or transformed into planets – SIRTF may help to solve this riddle.

Just as anthropologists sought “the missing link” between apes and humans, astronomers are embarking on a quest for a missing link in planetary evolution. Only instead of dusty fields and worn shovels, their laboratory is the universe, and their tool of choice is NASA?s new Space Infrared Telescope Facility.

Launched on Aug.25, NASA’s fourth and final Great Observatory will soon set its high-tech infrared eyes on, among other celestial objects, the dusty discs surrounding stars where planets are born.

While other ground- and space-based telescopes have spied these swirling “circumstellar” discs, both young and old, they have missed middle-aged discs for various reasons. The Space Infrared Telescope Facility’s unprecedented sensitivity and resolution will allow it to fill in this gap ? and in the process answer fundamental questions regarding how planets, including those resembling Earth, may form.

“With the Space Infrared Telescope Facility, we anticipate seeing many planetary discs at all stages of development,” says Dr. Karl Stapelfeldt of JPL, a scientist with the mission. “By studying how they change over time, we may be able to determine what conditions favor planet formation.”

Circumstellar discs are a natural step in the evolution of stars. Stars begin life as dense cocoons of gas and dust, then as pressure and gravity kick in, they begin to coalesce, and a flat ring of gas and dust takes shape around them. As stars continue to age, they suck material from this disc into their core. Eventually, a state of equilibrium is reached, leaving a more mature star encircled by a stable disc of debris.

It is around this time, about 10 million years into the lifetime of the star, that astronomers believe planets arise. Dust particles in the discs are thought to collide to form larger bodies, which ultimately sweep out gaps in the discs, much like those lying between the rings of Saturn.

“You can think of planets as wrecking balls that either clear away debris or gather it up as if it were mud,” says Dr. George Rieke, principal investigator on one of the three science instruments onboard the observatory.

Infrared telescopes can sense the glow of the cosmic dust that makes up these discs; however, they cannot detect planets directly. Planets have less surface area than their equivalent in dust grains and thus give off less infrared light. This is the same reason coffee is ground up before brewing: the larger combined surface area of the coffee grains results in a more robust pot of coffee.

Past observations of circumstellar discs generally fall into two categories: young, opaque discs (called protoplanetary discs) with more than enough mass to match our own solar system’s planetary bodies; or older, transparent discs (called debris discs) with masses equal to a few moons, and doughnut-like holes at their center. Middle-aged discs linking these two developmental stages have gone undetected.

One of the questions astronomers hope to address with the Space Infrared Telescope Facility is: What happened to all the mass observed in the younger discs? Somewhere in their evolution, mass is either eaten up by the star, ejected by the star ? or transformed into planets that lie in the doughnut holes of the discs. By analyzing the composition and structure of the “missing link” discs, astronomers hope to solve this riddle, and better understand how planetary systems like our own evolved.

Original Source: NASA News Release

Posted on by Fraser Cain

Sea Launch… On Land?

Image credit: Sea Launch

Until now, Sea Launch was known for its ocean-based launch platform which is towed out to the Pacific Ocean to launch rockets from the Earth’s equator, but a new offering will occasionally see the company launching from dry land – in Kazakhstan. Sea Launch will be offering launch services from the Baikonur cosmodrome; the same place that Russia launches its rockets. “Land Launch” will use existing Zenit launch facilities to lift cargos in the 2,500-3,500 kg range to geosyncronous orbits. The first launch is scheduled for October 4th, 2005.

Following the 10th successful Sea Launch mission on Sept. 30, the Sea Launch Board of Directors met and resolved to go forward with plans to offer launch services from the Baikonur Cosmodrome in Kazakhstan, in addition to its sea-based launches at the Equator. The new offering, Land Launch, is based on the collaboration of Sea Launch Company and Space International Services (SIS), of Russia, to meet the launch needs of commercial customers with medium weight satellites.

Optimizing on heritage hardware, systems and expertise, the Land Launch system will use a version of the Sea Launch Zenit-3SL rocket to lift commercial satellites in the 2000-3500 kg range to geosynchronous transfer orbit, and heavier payloads to inclined or lower orbits. A two-stage configuration of the same rocket will also be available for launching heavy payloads, or groups of payloads, to low Earth orbits. Payloads and vehicles will be processed and launched from existing Zenit facilities at the Baikonur launch site.

“Land Launch represents a major opportunity for Sea Launch to expand its role in the commercial space transportation arena,” said Jim Maser, president and general manager of Sea Launch. “We responded to the need for cost-efficiency and schedule assurance in the heavy-lift market. Now, through our Land Launch offering, we are responding to the demand for reliable, single payload capabilities in the medium-weight payload market.”

“All SIS partners look forward to bringing their extensive expertise to this project,” said Igor Alekseev, director, SIS. “With the strong support of the Russian Aviation and Space Agency and the participation of Sea Launch, we are confident that Land Launch will bring an outstanding service to the market.”

With an initial launch capability slated for the 4th Quarter of 2005, Land Launch will use existing Zenit technology and infrastructure, minimizing risk, cost and start-up time. Sea Launch will provide commercial customers with mission management and the Boeing-led quality assurance and hardware acceptance procedures that have contributed to the outstanding reliability of the Sea Launch system. SIS will be responsible for launch operations.

Boeing Launch Services, Inc. (BLS) will manage marketing and sales for the new offering, in a seamless expansion of their current support to Sea Launch customers. Established in 2001, the BLS team represents a family of vehicles to meet every payload lift requirement, from 1,000 kg -13,000 kg. For more information, go to: www.boeing.com/launch

Sea Launch Company, LLC, based in Long Beach, Calif., provides reliable heavy lift launch services to commercial satellite customers. The international partners include Boeing (U.S.), Kvaerner Group (Norway), RSC Energia (Russia) and SDO Yuzhnoye/PO Yuzhmash (Ukraine). Established in 1995, Sea Launch has completed ten successful missions. For more information, visit the Sea Launch website at www.sea-launch.com

Space International Services is a Moscow-based venture, founded by SDO Yuzhnoye/PO Yuzhmash, the Design Bureau of Transport Machinery (KBTM, of Russia), and TseNKI (Center for Ground-based Space Infrastructure, of Russia), under the Russian Space and Aviation Agency.

Original Source: Sea Launch news release

Posted on by Fraser Cain

SMART-1 is Doing Well

Image credit: ESA

The European Space Agency’s SMART-1 spacecraft has completed its 50th orbit of the Earth; operating its ion engine for more than 560 hours. The engine can only fire for half of the orbit because the spacecraft needs to raise its orbit until it reaches the Moon. ESA controllers have performed a series of tests on the spacecraft, and almost everything seems to be working perfectly – there’s a minor problem with its star-tracker. The spacecraft is expected to reach the Moon by March 2005, when it will begin mapping surface minerals and ice.

The spacecraft is now completing its 50th orbit and has completed more than 560 hours in space. The main actvity of the last week has been to repeatedly use the electric propulsion engine to gradually alter the spacecraft’s orbit. This is limited to around 15 hours a day based on whether the spacecraft is in eclipse. So far the engine has generated thrust for an accumulated time of about 240 hours.

The electric propulsion engine performance has been periodically monitored by means of telemetry data transmitted by the spacecraft and by radio-tracking at the ground stations. The EP performance has been constantly improving, as expected, during the thrusting phase. During the first firing we measured an underperformance of about 3%, as expected in the early operations of the engine in its first use. Today we have a slight over-performance of about 0.5% which gives us confidence in the excellent conditions of the electric propulsion system.

The electric power provided by the solar arrays is nominal. The expected degradation due to the radiation environment is less severe then the worst case scenario. We can, therefore, assume that we shall be able to thrust at full power for quite some time.

The thermal subsystem is performing very well: all the temperatures are as expected and the heater power consumption is lower than estimated. This is a comfortable situation and gives us confidence that the system will be able to cope well with the long eclipse seasons in the spring of next year.

The communication, data handling and on-board software subsystems have been performing nominally so far. The attitude control subsystem has, in general, been working very well and the controller performance during the thrusting phase has been so smooth and accurate that there has been no need to use the hydrazine thrusters to desaturate the small reaction wheels used as main actuators.

The main area of concern is the star tracker performance. This advanced autonomous star mapper has recently failed to provide good attitude information in a few cases around perigee and eclipse periods. Although the attitude control system can cope with these occasional problems, the spacecraft planned operations are disturbed by these events. The operation team at ESOC is obliged to reschedule the operations to take into account these events. In the meantime the ESTEC project and industry teams are busy trying to find an explanation to these anomalies. Despite this inconvenience the thrusting periods are maintained. More on the subject will be provided in future reports.

Orbital/Trajectory information
The SMART-1 orbit is continuously modified by the effects of the electric propulsion low thrust. The osculating orbital elements are periodically computed by the ESOC specialists. These elements define the so called ‘osculating orbit’ which would be travelled by the spacecraft if at that instant all perturbations, including EP thrust, would cease. So it is an image of the situation at that moment. In reality the path travelled by the spacecraft is a continuous spiral leading from one orbit to another.

In this diagram the GTO, the osculating orbits at launch and at different times are plotted. The large orbit, marked ‘final’, is the one we expect to achieve at the end of the radiation belt escape in about two months.

From the start, the electric propulsion system has managed to increase the semi-major axis of the orbit by 1555 km, increasing the perigee altitude from the original 656 km to 2035 km and the orbital period by more than one hour, from the initial 10 hours 41 minutes to the present 11 hours 42 minutes.

Original Source: ESA News Release