Posted on by Fraser Cain

New Areas in the Forum

I’ve added a couple of new areas to the Universe Today Forums which I think will be pretty helpful. The first is a Totally Off-Topic area where people can yack about stuff that has nothing to do with space and astronomy. Hopefully that will keep the rest of the forums purely about space.

A more useful area, however, is “Questions and Answers“. If you’ve got a nagging question about space or a current mission, go ahead and ask it here. People in the forum will try and help you out, and I’ll also be submitting the really tough questions to experts in space and astronomy so we can help get to the bottom of this for you.

Come and join us!

Fraser Cain
Publisher
Universe Today

P.S. Thanks to the overwhelming number of you who replied to my last email. There’s definitely an email delay to some of you. I’m working with my hosting provider to get to the bottom of this.

Posted on by Fraser Cain

Madhavan Nair Selected as New Chairman of ISRO

Image credit: ISRO

Mr. G Madhavan Nair has been appointed as the new Chairman of the Indian Space Research Organization (ISRO). Previous to this new position, Nair was the Director of Vikram Sarabhai Space Centre, and has been involved in the agency since 1967 when he was first hired at the Thumba Equatorial Rocket Launching Station. His predecessor, Dr K Kasturirangan, left the position after he was nominated for India’s Upper House of Parliament.

The Appointments Committee of the Cabinet has appointed Mr G Madhavan Nair as Secretary, Department of Space, Chairman Space Commission and Chairman, ISRO. Mr Madhavan Nair, who was Director, Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, was holding additional charge of these posts since September 1, 2003 after Dr K Kasturirangan relinquished the office consequent to the President of India nominating him as Member of Rajya Sabha (Upper House of Parliament).

Mr Madhavan Nair is a leading technologist in the field of Rocket Systems. He has made significant contributions to the development of multistage Satellite Launch Vehicles for the Indian space programme. As Director, VSSC, he has led research and development in the area of satellite launch vehicles for orbiting spacecraft for remote sensing and communications.

After graduating in Engineering from Kerala University in 1966, Mr Madhavan Nair underwent training at Bhabha Atomic Research Center (BARC), Mumbai, and joined Thumba Equatorial Rocket Launching Station (TERLS) in 1967. Since then, he has held various positions posting illustrious milestones on his way to the present position. He made impressive contributions to the first Indian Satellite Launch Vehicle, SLV-3. Subsequently, as Project Director, he brought to fruition the development of India’s first operational Satellite Launch Vehicle, PSLV. With six successful launches so far, PSLV has convincingly demonstrated its reliability for not only launching multiple satellites including placing them in different orbits in a single launch but also its capability to place satellites in Geo-synchronous Transfer Orbit (GTO). PSLV is also proposed for launching India’s unmanned lunar craft under Chandrayaan-1 mission. Mr Madhavan Nair, also contributed to the indigenous development of cryogenic technology and as Dire
ctor, Liquid Propulsion Systems Centre during 1995-99, he gave concrete shape for the vital infrastructure for its development.

Mr Madhavan Nair took over as the Director of VSSC in 1999 and in the following two years led the successful flight of GSLV in the very first attempt followed by another successful flight in May 2003. GSLV has since been commissioned into operational service for launching 2000 kg class satellites into GTO.

Mr Madhavan Nair has been the leader of the Indian delegation to the United Nations Committee on Peaceful Uses of Outer Space (UN-COPUOS). He has received several prestigious awards including Shri Om Prakash Bhasin Award, Swadeshi Sastra Puraskar Award, FIE Foundation Award and Vikram Sarabhai Memorial Gold Medal of ISCA. He was conferred ‘Padma Bhushan’ by the President of India in 1998.

The outgoing Chairman of ISRO, Dr K Kasturirangan, saw during his tenure of nearly a decade, the Indian space programme witnessing several major milestones including the commissioning of India’s prestigious launch vehicle, the Polar Satellite Launch Vehicle (PSLV) and more recently, the commissioning of all important Geo-synchronous Satellite Launch Vehicle (GSLV). Further, the world’s best civilian remote sensing satellites, IRS-1C and 1D, experimental remote sensing satellites, IRS-P2 and IRS-P3, besides
an exclusive ocean observation satellite IRS-P4 were launched. A 1-m spatial resolution experimental satellite, TES, was also built and launched during his tenure. He also saw the launching of second generation INSAT satellites that vastly enhanced the capacity of INSAT system for telecommunication, television broadcasting and meteorology. Three satellites under the third generation series, INSAT-3A, INSAT-3B, and INSAT-3C were also launched besides an exclusive meteorological satellite, KALPANA-1. He chaired some of the prestigious international committees, such as, the International Committee on Earth Observation Satellites (CEOS), Panel for Space Research in Developing countries of COSPAR/ICSU, and the committee meeting at senior official level of UN-ESCAP, that led to the adoption of the “Delhi Declaration” by the Ministers of the region (1999-2000).

Dr B N Suresh is the new Director of VSSC. Dr B N Suresh, Outstanding Scientist at ISRO’s Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, has been appointed as the Director of the Centre and he took over charge on September 20, 2003 from Mr Madhavan Nair. Dr Suresh joined ISRO in July 1969 and is an expert in control and guidance systems. He has made significant contributions to the design and development of all satellite launch vehicles of ISRO – SLV-3, ASLV, PSLV and GSLV.

Original Source: ISRO News Release

Posted on by Fraser Cain

Brown Dwarf is Actually a Binary System

Image credit: Gemini

Astronomers were searching for planets around nearby star Epsilon Indi when they discovered something unusual. A previously-known brown dwarf star orbiting Epsilon Indi has a companion of its own. This new companion, known as Epsilon Indi Bb, orbits the larger brown dwarf (Epsilon Indi Ba) at a distance of only 2.2 astronomical units. Both objects are part of a new class of stars called T-dwarfs; they have diameters similar to Jupiter but have significantly more mass.

While searching for planet-sized bodies that might accompany the nearby star system Epsilon Indi, astronomers using the Gemini South telescope in Chile made a related but unexpected detection.

Widely observed by telescopes on the ground and in space, Epsilon Indi was known to host an orbiting companion, called Epsilon Indi B, which was discovered last year and is the nearest known specimen of a brown dwarf. Brown dwarfs are very small, cool stars thirty to forty times more massive than Jupiter but of similar size. Despite all the observing, it took the combination of Gemini’s powerful infrared capabilities and the extremely sensitive spectrograph/imager called PHOENIX (without adaptive optics) to reveal the more elusive body.

“Epsilon Indi Ba is the closest confirmed brown dwarf to our solar system,” says Dr. Gordon Walker (University of British Columbia, Vancouver, Canada), who led the research team that includes Dr. Suzie Ramsay Howat (UK Astronomy Technology Centre, Edinburgh, UK). Dr. Walker explains, “With the detection of Epsilon Indi Bb, we now know that Epsilon Indi Ba has a close companion that appears to be another, even cooler brown dwarf. One certainty is that the Epsilon Indi system is even more interesting than we previously thought.”

The team of scientists who detected Epsilon Indi Bb using the Gemini South Telescope on Cerro Pach?n, Chile, were the first to report this finding, which was published in the IAU Circular Volume 8818. Subsequently, the VLT (Very Large Telescope) announced that scientists had actually observed the object five days earlier (using adaptive optics), and their finding is reported at http://xxx.lanl.gov/abs/astro-ph?0309256.

“When the target was acquired and we saw that there were clearly two objects close together, we initially thought it must be the wrong object. Epsilon Indi Ba, formerly called Epsilon Indi B, had been observed before and in those observations, no one noticed the companion object. It was a tremendous surprise for us,” says Dr. Kevin Volk (Gemini Observatory, La Serena, Chile) who was actually making the observation at the Gemini South telescope along with Dr. Robert Blum (CTIO, La Serena, Chile).

The serendipitous nature of the detection took the science team–whose members are from Canada, the U.K., the U.S. and Chile–by surprise. Dr. Blum elaborates, “We then found that the companion, named Epsilon Indi Bb, is invisible in the methane band where previous Gemini observations had been taken. The coolest brown dwarfs are very faint and hard to detect, but there may be vast numbers of them–which makes this detection important.”

Epsilon Indi is the fifth brightest star in the southern constellation of Indus and is located about 11.8 light years away from our solar system. The star is similar to but cooler than our sun. The projected separation as seen on the sky between Epsilon Indi and Indi Ba is approximately 1500 AUs (one AU or Astronomical Unit is the average distance between the Earth and the Sun or about 93 million miles/150 million kilometers), and the distance between Epsilon Indi Ba and the newly discovered Epsilon Indi Bb is at least 2.2 AUs.

“Because this system is so close to us, it appears to move quite rapidly in the sky,” says Dr. Volk. “We were able to confirm our detection–and rule out a more distant background object–within a few weeks since we could detect the motion of the system relative to the background stars relatively quickly.”

As the facts surrounding the detection become clearer with additional spectroscopic data, the research team expects that important details about Epsilon Indi Bb will be revealed. “Unfortunately, the window for observing this system is nearly closed for this year, so we will have to wait until early next year when we can see this system again in the morning sky,” says Dr. David Balam (University of Victoria, Canada).

The data recently obtained from Gemini show that Epsilon Indi Bb is cooler and less massive than Epsilon Indi Ba as demonstrated by its significantly lower brightness and deep methane absorption. Methane absorption is a key indicator for low mass objects since gaseous methane can only exist in the lower temperature environments of the atmospheres of brown dwarfs and planets where the gas can exist.

“Methane absorption was the key to the detection,” says Dr. Walker, “because Dr. Volk happened to catch sight of Epsilon Indi Bb through one of the ‘windows’ between the methane absorption bands. Because the absorption bands block longer wavelength infrared light, Epsilon Indi Bb was visible when viewed at shorter infrared wavelengths.”

Epsilon Indi Ba and Bb are members of a recently discovered type of astronomical object–the “T” class brown dwarfs. These T-dwarfs have diameters approximately equal to Jupiter but with more mass. Spectra of Epsilon Indi Ba, taken with PHOENIX by Dr. Verne Smith (University of Texas, El Paso) and collaborators, show the Epsilon Indi Ba has 32 times the mass of Jupiter and a 1500-degree surface temperature. It is spinning about three times faster than Jupiter. Epsilon Indi Bb has less mass, is cooler, but is still much more massive and hotter than Jupiter. Like Jupiter, the T-dwarfs do not have enough mass to make energy the way the sun does from nuclear fusion. Epsilon Indi Ba and Bb are glowing from heat resulting from the mass pushing down on the interior.

PHOENIX, the instrument that is responsible for producing the data, is a near-infrared, high-resolution spectrometer that was built by the National Optical Astronomy Observatory (NOAO) in Tucson, Arizona, and was commissioned on Gemini South in 2001. Dr. Ken Hinkle (NOAO, Tucson, Arizona) said, “PHOENIX was designed for exactly this type of research. It is the first high-resolution infrared spectrograph on a Gemini telescope, and the first high-resolution infrared spectrograph on any southern hemisphere telescope.”

Dr. Phil Puxley, Associate Director of Gemini South, adds, “Gemini’s infrared optimization makes the 8-meter twin telescopes ideal for capturing such serendipitous discoveries. Finds like this are exactly what Gemini is designed to do and this sort of exciting work demonstrates the potential of Gemini’s science.”

Epsilon Indi is visible with the naked eye from June to December in the southern hemisphere. It can be detected with the locator map available at http://www.gemini.edu/science/epsilonindi-images.html, which also contains other images and illustrations.

The Gemini Observatory is an international collaboration that has built two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located at Mauna Kea, Hawai`i (Gemini North) and the other telescope at Cerro Pach?n in central Chile (Gemini South), and hence provide full coverage of both hemispheres of the sky. Both telescopes incorporate new technologies that allow large, relatively thin mirrors under active control to collect and focus both optical and infrared radiation from space.

The Gemini Observatory provides the astronomical communities in each partner country with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the UK Particle Physics and Astronomy Research Council (PPARC), the Canadian National Research Council (NRC), the Chilean Comisi?n Nacional de Investigaci?n Cientifica y Tecnol?gica (CONICYT), the Australian Research Council (ARC), the Argentinean Consejo Nacional de Investigaciones Cient?ficas y T?cnicas (CONICET) and the Brazilian Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq). The Observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

Original Source: Gemini News Release

Posted on by Fraser Cain

Galileo Plunges Into Jupiter

Image credit: NASA/JPL

NASA’s Galileo spacecraft was intentionally crashed into Jupiter on Sunday, ending 14 years of service to science and exploration. The spacecraft entered Jupiter’s thick atmosphere and disintegrated at 1857 GMT (2:57pm EDT), but the last signals arrived at Earth nearly an hour later because of the great distance to Jupiter. At the end of its mission, Galileo lacked the fuel to escape the Jovian system so scientists decided to crash it into Jupiter to avoid contaminating any potential life on Europa, which is believed to have liquid water oceans under a thick sheet of ice.

The Galileo spacecraft’s 14-year odyssey came to an end on Sunday, Sept. 21, when the spacecraft passed into Jupiter’s shadow then disintegrated in the planet’s dense atmosphere at 11:57 a.m. Pacific Daylight Time. The Deep Space Network tracking station in Goldstone, Calif., received the last signal at 12:43:14 PDT. The delay is due to the time it takes for the signal to travel to Earth.

Hundreds of former Galileo project members and their families were present at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., for a celebration to bid the spacecraft goodbye.

“We learned mind-boggling things. This mission was worth its weight in gold,” said Dr. Claudia Alexander, Galileo project manager.

Having traveled approximately 4.6 billion kilometers (about 2.8 billion miles), the hardy spacecraft endured more than four times the cumulative dose of harmful jovian radiation it was designed to withstand. During a previous flyby of the moon Amalthea in November 2002, flashes of light were seen by the star scanner that indicated the presence of rocky debris circling Jupiter in the vicinity of the small moon. Another measurement of this area was taken today during Galileo’s final pass. Further analysis may help confirm or constrain the existence of a ring at Amalthea’s orbit.

“We haven’t lost a spacecraft, we’ve gained a steppingstone into the future of space exploration,” said Dr. Torrance Johnson, Galileo project scientist.

The spacecraft was purposely put on a collision course with Jupiter because the onboard propellant was nearly depleted and to eliminate any chance of an unwanted impact between the spacecraft and Jupiter’s moon Europa, which Galileo discovered is likely to have a subsurface ocean. Without propellant, the spacecraft would not be able to point its antenna toward Earth or adjust its trajectory, so controlling the spacecraft would no longer be possible. The possibility of life existing on Europa is so compelling and has raised so many unanswered questions that it is prompting plans for future spacecraft to return to the icy moon.

Galileo was launched from the cargo bay of Space Shuttle Atlantis in 1989. The exciting list of discoveries started even before Galileo got a glimpse of Jupiter. As it crossed the asteroid belt in October 1991, Galileo snapped images of Gaspra, returning the first ever close-up image of an asteroid. Less then a year later, the spacecraft got up close to yet another asteroid, Ida, revealing it had its own little “moon,” Dactyl, the first known moon of an asteroid. In 1994 the spacecraft made the only direct observation of a comet impacting a planet– comet Shoemaker-Levy 9’s collision with Jupiter.

The descent probe made the first in-place studies of the planet’s clouds and winds, and it furthered scientists’ understanding of how Jupiter evolved. The probe also made composition measurements designed to assess the degree of evolution of Jupiter compared to the Sun.

Galileo made the first observation of ammonia clouds in another planet’s atmosphere. It also observed numerous large thunderstorms on Jupiter many times larger than those on Earth, with lightning strikes up to 1,000 times more powerful than on Earth. It was the first spacecraft to dwell in a giant planet’s magnetosphere long enough to identify its global structure and to investigate the dynamics of Jupiter’s magnetic field. Galileo determined that Jupiter’s ring system is formed by dust kicked up as interplanetary meteoroids smash into the planet’s four small inner moons. Galileo data showed that Jupiter’s outermost ring is actually two rings, one embedded within the other.

Galileo extensively investigated the geologic diversity of Jupiter’s four largest moons: Ganymede, Callisto, Io and Europa. Galileo found that Io’s extensive volcanic activity is 100 times greater than that found on Earth. The moon Europa, Galileo unveiled, could be hiding a salty ocean up to 100 kilometers (62 miles) deep underneath its frozen surface containing about twice as much water as all the Earth’s oceans. Data also showed Ganymede and Callisto may have a liquid-saltwater layer. The biggest discovery surrounding Ganymede was the presence of a magnetic field. No other moon of any planet is known to have one.

The prime mission ended six years ago, after two years of orbiting Jupiter. NASA extended the mission three times to continue taking advantage of Galileo’s unique capabilities for accomplishing valuable science. The mission was possible because it drew its power from two long-lasting radioisotope thermoelectric generators provided by the Department of Energy.

“The mission was a testimonial to the persistence of NASA even through tremendous challenges. It was a phenomenal mission,” said Sean O’Keefe, NASA administrator.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Early Supernovae Seeded the Universe With Elements

Image source: CfA

According to cosmologists, the early Universe only had a mixture of hydrogen, helium and other lighter elements, but none of the heaver elements required for life – like carbon. From the original gasses, giant stars formed – some were 200 times larger than our Sun – lived for a brief time, often just a few million years. These giant stars converted up to 50% of their material into heaver elements, mostly iron, before exploding violently as supernovae. The James Webb telescope, due for launch after 2011 will be so sensitive it should be able to look back to watch these supernovae happening.

The early universe was a barren wasteland of hydrogen, helium, and a touch of lithium, containing none of the elements necessary for life as we know it. From those primordial gases were born giant stars 200 times as massive as the Sun, burning their fuel at such a prodigious rate that they lived for only about 3 million years before exploding. Those explosions spewed elements like carbon, oxygen and iron into the void at tremendous speeds. New simulations by astrophysicists Volker Bromm (Harvard-Smithsonian Center for Astrophysics), Naoki Yoshida (National Astronomical Observatory of Japan) and Lars Hernquist (CfA) show that the first, “greatest generation” of stars spread incredible amounts of such heavy elements across thousands of light-years of space, thereby seeding the cosmos with the stuff of life.

This research is posted online at http://arxiv.org/abs/astro-ph/0305333 and will be published in an upcoming issue of The Astrophysical Journal Letters.

“We were surprised by how violent the first supernova explosions were,” says Bromm. “A universe that was in a pristine state of tranquility was rapidly and irreversibly transformed by a colossal input of energy and heavy elements, setting the stage for the long cosmic evolution that eventually led to life and intelligent beings like us.”

Approximately 200 million years after the Big Bang, the universe underwent a dramatic burst of star formation. Those first stars were massive and fast-burning, quickly fusing their hydrogen fuel into heavier elements like carbon and oxygen. Nearing the end of their lives, desperate for energy, those stars burned carbon and oxygen to form heavier and heavier elements until reaching the end of the line with iron. Since iron cannot be fused to create energy, the first stars then exploded as supernovae, blasting the elements that they had formed into space.

Each of those first giant stars converted about half of its mass into heavy elements, much of it iron. As a result, each supernova hurled up to 100 solar masses of iron into the interstellar medium. The death throes of each star added to the interstellar bounty. Hence, by the remarkably young age of 275 million years, the universe was substantially seeded with metals.

That seeding process was aided by the structure of the infant universe, where small protogalaxies less than one-millionth the mass of the Milky Way crammed together like people on a crowded subway car. The small sizes of and distances between those protogalaxies allowed an individual supernova to rapidly seed a significant volume of space.

Supercomputer simulations by Bromm, Yoshida, and Hernquist showed that the most energetic supernova explosions sent out shock waves that flung heavy elements up to 3,000 light-years away. Those shock waves swept huge amounts of gas into intergalactic space, leaving behind hot “bubbles,” and triggered new rounds of star formation.

Supernova expert Robert Kirshner (CfA) says, “Today this is a fascinating theory, based on our best understanding of how the first stars worked. In a few years, when we build the James Webb Space Telescope, the successor to the Hubble Space Telescope, we should be able to see these first supernovae and test Volker’s ideas. Stay tuned!”

Lars Hernquist notes that the second generation of stars contained heavy elements from the first generation – seeds from which rocky planets like Earth could grow. “Without that first, ‘greatest generation’ of stars, our world would not exist.”

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics 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: CfA News Release

Posted on by Fraser Cain

SMART-1 Launch Date Set

Image credit: ESA

The launch date for the European Space Agency’s SMART-1 spacecraft has been set for early morning of September 28. Earlier this week the spacecraft was attached to the top of an Ariane 5 rocket at the Kourou spaceport in French Guiana. When it finally does get into space, SMART-1 will use its ion engine to slowly spiral away from the Earth until it gets captured by the gravity of the Moon. Once its in orbit around the Moon, it will map the chemical composition of the surface with greater detail than ever done before. It will also search for evidence of water ice at the Moon’s south pole.

The launch date for ESA’s SMART-1 mission to the Moon is confirmed as during the night of 27-28 September 2003.

The ‘launch window’ will be 8:02 p.m. to 8:21 p.m. on Saturday, 27 September, local time in Kourou, French Guiana, and 1:02 a.m. to 1:21 a.m. on Sunday, 28 September, CEST.

Earlier this week, the SMART-1 spacecraft completed the first 30 metres of its trip to the Moon when it was put on board its Ariane 5 launcher at the Kourou spaceport in French Guiana.

As ESA scientists and engineers watched, the spacecraft looked very small, with its Ariane 5 mounting adapter, when it was raised the 30 metres up to the top of the launcher inside the Final Assembly Building (BAF). Within an hour it was sitting on the rocket’s upper stage.

The spacecraft is pictured here being made ready for flight and having its solar panel array protection removed. The next step is to enclose the spacecraft with the 2.6-metre raising cylinder, which carries the second passenger satellite, E-Bird, on top of SMART-1.

Original Source: ESA News Release

Posted on by Fraser Cain

Shuttle’s Return to Flight Pushed Back to Summer

The return to flight of the space shuttle will probably be pushed back to midsummer according to NASA officials; not March as they had originally anticipated. The delay is being caused by the complexity of implementing the safety recommendations of the Columbia accident investigation, which called for additional cameras, day launches, and redesigns to several shuttle components. When Atlantis finally does launch with only four astronauts, its only purpose will be to test out the new safety improvements. It will dock with the International Space Station and allow the astronauts to test methods for finding and repairing damage to the shuttle’s exterior.

Posted on by Fraser Cain

China Will Help Develop the Galileo Network

Image credit: ESA

The European Union announced on Thursday that China will play a role in the development of the Galileo constellation of satellites, which are designed to provide a similar solution as the US-based Global Positioning System. The exact commitments from China haven’t been detailed yet, but the two groups have set up a training, cooperation, and information centre for satellite navigation in China at Beijing University. Galileo will be built with 30 navigation satellites to provide complete global coverage – it’s expected to be fully operational by 2008.

Europe and China share a common interest in cooperating to bring the benefits of satellite navigation and Galileo in particular to transport, science, land management, disaster prevention and other user sectors.

Sharing research results, encouraging education, joint projects and industrial contacts are important means towards such goals.

In this context, the European Commission, the European Space Agency and the Chinese Ministry of Science and Technology have decided to establish a training, cooperation and information centre for satellite navigation in China. On the basis of bilateral discussions to date in the Europe-China Joint Technical Working Group, the decision has been taken to locate the centre at the renowned Beijing University.

The centre will be staffed initially by one or two experts supported by two administrative and technical assistants.

Mr F. Lamoureux, Director General for Energy and Transport at the European Commission, will inaugurate the centre together with Mr Shi Dinghuan, Secretary General of the Chinese Ministry of Science and echnology, at 11:00 on Friday 19 September in Beijing.

This will take place at the China-Europe Technical Training and Cooperation Centre, Room 323 ZhongGuanCun FangZheng Building, No 298, Chengfu Road, Haidian District (in front of the Beijing University East Gate).

The Galileo system will be built around 30 satellites (27 operational and three in reserve) stationed on three circular medium-Earth orbits at an altitude of 23 616 km and inclined at 56? to the equator. This configuration will provide excellent coverage of the entire planet. Two Galileo centres will be set up in Europe to control satellite operations and manage the navigation system.

Developed by ESA and the European Union on the basis of 50-50 cofinancing, Galileo will be a complete civil system, due to be operational from 2008, offering users in Europe, and throughout the world as well, a precise, secure satellite positioning service.

Original Source: ESA News Release

Posted on by Fraser Cain

SpaceDev Will Build SpaceshipOne Motor.

Image credit: Scaled

Scaled Composites announced today that it has selected San Diego-based SpaceDev to build the rocket engine for SpaceShipOne. The hybrid engine uses nitrous oxide and rubber, and was chosen for both safety and performance. SpaceShipOne is Scaled Composite’s entrant into the X-Prize; a $10 million prize to the first private company able to launch a 2-person crew to an altitude of 100 km. No future plans or launch dates have been announced but the spacecraft must complete a successful flight before the end of 2004 to claim the prize.

Four years ago, Scaled conducted a study of rocket engine technologies that were appropriate for its future manned sub-orbital spaceship design. The results of this study were that a hybrid configuration using nitrous oxide (liquid N2O) and HTPB (rubber) propellants would likely provide the safest solution with operating characteristics that would complement the intended mission.

In Jan 2000, Scaled defined a new integrated concept for the hybrid motor that allowed the entire propulsion system to be mounted to the spaceship by simple skirt flanges on the oxidizer tank. This concept, which cantilevers the case and nozzle directly to the tank, required an advanced all-composite design approach. By early 2001, Scaled had committed to developing the two main motor composite components in-house: The first is the nitrous oxide tank, a composite liner laid up onto titanium flanges, with a graphite over-wrap provided by Thiokol. The second is a unitized fuel case/nozzle component fabricated using a high-temperature composite insulator with a graphite/epoxy structure laid up onto an ablative nozzle supplied by AAE Aerospace.

In mid 2001, Scaled awarded contracts to two competing small businesses for the “rocket science”. Each company was independently responsible for the development of the motor’s ignition system, main control valve, injector, tank bulkheads, electronic controls, fill/dump/vent systems and fuel casting. The vendors, Environmental Aeroscience Corporation (eAc) of Miami and SpaceDev (SD) of San Diego, were also tasked with conducting the ground firing tests of their motor systems in Scaled’s test facility during the development phase.

In June 2002, Scaled selected eAc to supply the components at the tanks’ front end: the nitrous fill, vent and dump system components and associated plumbing. Both vendors continued the development of all the other propulsion components.

The ground firing development program started in November 2002 with a 15 second run by the SpaceDev team and ended early this month with a 90-second run by eAc. Both vendors demonstrated full design-duration firings during the nine-month development phase. All tests have exclusively used 100% flight hardware, with no boilerplate components and both vendors’ motor systems met the contracted performance. The tests validated the inherent safety of hybrid type motors, with no instances of structural failure, hot-gas breach, explosion or other anomaly that would have put SpaceShipOne in jeopardy.

Because both teams were so closely matched, and since both have developed satisfactory motors the process to select one of these vendors to enter the motor qualification and flight test phase was difficult. However, today, Scaled is pleased to announce that it has awarded the contract for propulsion support for the SpaceShipOne flight test phase to SpaceDev, of San Diego.

Scaled now looks forward to entering into the historic phase of private manned space flight.

Original Source: Scaled Composites News Release

Posted on by Fraser Cain

ESA’s View of Hurricane Isabel

Image credit: ESA

The European Space Agency is helping to track the movement of Hurricane Isabel using its ERS-2 spacecraft, and released this photo of the storm Thursday morning as it menaced the East Coast of the US. ERS-2 has also been gathering other information about the storm, including sea surface temperatures, wind and rainfall levels. Isabel is a Category 2 hurricane, and expected to make landfall in the early afternoon on Thursday in North Carolina.

As Hurricane Isabel converges on the US East Coast, a veteran ESA spacecraft has provided meteorologists with crucial insights into the underlying pressure system powering the storm.

An entire flotilla of satellites is being kept busy tracking Hurricane Isabel in visible and infrared light, as well as gathering additional measurements of local sea surface temperature, wind and rainfall levels. ESA spacecraft ERS-2 has made the picture more detailed still by discerning the wind speed and direction around the hurricane’s cloud and rain-wracked heart.

ERS-2 instruments include a C-band scatterometer, which works by sending a high-frequency radar pulse down to the ocean, then analysing the pattern of backscatter reflected back again. Scatterometers are particularly useful in measuring wind speed and direction at the sea surface, by detecting signature scatter from ripples on the water caused by wind.

ERS-2’s scatterometer is less sensitive than comparable space-based instrumentsto rain or bad weather, and can gather data both day and night. This makes it invaluable as an early detector of Atlantic storms ? especially in the current hurricane season.

The Isabel data was obtained mid-afternoon Wednesday at one of ESA?s ground stations in Gatineau Canada, then rapidly delivered to meteorology offices worldwide. At the Reading-based European Centre for Medium-Range Weather Forecasts (ECMWF), it was analysed against the surface wind pattern predicted by their existing software simulation of Isabel, run on powerful supercomputers.

“The ERS wind data is very valuable to us,” said Hans Hersbach of ECMWF. “It shows differences with our analysis, for instance a lack of inward wind flow into the centre. By assimilating the data into our analysis we improve our forecasting skills.

“The ESA scatterometer data was routinely assimilated into our analysis after 1997, until it become no longer available early this century. Now the service has been resumed we are making use of it once more.”

ESA’s ERS-2 has been in orbit since 1995, but the service from the scatterometer was interrupted in 2001. A degradation in attitude control prevented access to the data. Meteorologists lost a valuable window on the weather ? until this summer, when after two-and-a-half-years of effort, new processing software developed by the Belgian Royal Military Academy (RMA) compensated for the degradation and regained access to scatterometer measurements.

The software algorithm was installed in ground stations at Kiruna in Sweden, Maspalomas in the Canary Islands Gatineau in Canada as well as Frascati in Italy, with an additional installation planned for West Freugh in Scotland. The new service began at the end of August, just in time for Hurricane Isabel’s dramatic arrival.

To maintain future continuity of scatterometer coverage, a new more advanced scatterometer instrument called ASCAT is part of the payload for ESA?s MetOp mission, currently due to launch in 2005.

Inside a hurricane
Hurricanes are large powerful storms that rotate around a central area of extreme low pressure. They arise in warm tropical waters that transfer their heat to the air. The warmed air rises rapidly, in the process creating low pressure at the water surface. Winds begin rushing inwards and upwards around this low-pressure zone.

Currently classed at Category Two on the five-point Saffir-Simpson Hurricane scale, Isabel originated in the eastern Atlantic last week. It is currently moving northwest at only about 24 kilometres an hour but winds within it are rotating at about 160 km per hour. Meteorologists forecast the hurricane will make landfall in North Carolina on Thursday.

Original Source: ESA News Release