Posted on by Fraser Cain

Stardust Gets Ready for Comet Encounter

Image credit: NASA/JPL

In less than 2 days, NASA’s Stardust spacecraft will fly past Comet Wild 2 – on January 2 at 0740 UTC (2:40 am EST). The spacecraft has already entered the comet’s halo; the cloud of dust and gas surrounding its nucleus. This is a dangerous part of the journey because the spacecraft could collide with particles from the comet which are moving at 6.1 kilometres per second. In order to minimize any damage, Stardust has several shields made of composite material which dissipate the energy from colliding particles. The spacecraft will collect particles from the comet and then return them to Earth in 2006.

T-minus 48 hours and counting to a historic rendezvous, NASA’s Stardust spacecraft has officially entered a comet’s coma, the cloud of dust and gas surrounding the nucleus. Stardust is scheduled to hurtle past comet Wild 2 on January 2, 2004, at approximately 2:40 a.m. EST.

“Just like in Star Trek we have our shields up,” said Tom Duxbury, Stardust program manager at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. “The spacecraft has entered Wild 2’s coma, which means at any time we could run into a cometary particle. At 6.1 kilometers per second (approximately 3.8 miles per second), this is no small event.”

To protect Stardust against the blast of expected particles and rocks as it travels approximately 300 kilometers (186 miles) from the Wild 2 nucleus, the spacecraft rotated, so it is flying in the shadow of its “Whipple Shields”. The shields are named for American astronomer Dr. Fred L. Whipple. In the 1950s, he came up with the idea of shielding spacecraft from high-speed collisions with bits and pieces ejected from comets.

The system includes two bumpers at the front of the spacecraft, which protect Stardust’s solar panels, and another shield protecting the main spacecraft body. Each of the shields is built around composite panels designed to disperse particles as they impact. Blankets of Nextel ceramic cloth that dissipates and spreads debris augment them.

Stardust has traveled approximately 3.7 billion kilometers (approximately 2.3 billion miles) since its February 7, 1999 launch. It is closing the gap with Wild 2 at 22,000 kph (approximately 13,640 mph).

On Jan. 2, Stardust will fly through the halo of dust and gas that surrounds the nucleus of comet Wild 2. While large portions of the spacecraft will be hidden behind Whipple shields, others are designed to endure the celestial sandblasting as they collect, analyze and store samples. The Stardust spacecraft will return to Earth in January 2006, and its sample return capsule will make a soft landing at the U.S. Air Force Utah Test and Training Range. The collected microscopic particle samples of comet and interstellar dust will be taken to the planetary material curatorial facility at NASA’s Johnson Space Center, Houston, for analysis.

Stardust’s cometary and interstellar dust samples may help provide answers to fundamental questions about the origins of the solar system. More information about the Stardust mission is available on the Internet, at:

http://stardust.jpl.nasa.gov

Stardust is part of NASA’s Discovery Program of low-cost, highly focused science missions. It was built by Lockheed Martin Space Systems, Denver, and is managed by JPL for NASA’s Office of Space Science, Washington. JPL is a division of the California Institute of Technology in Pasadena, Calif. The principal investigator is astronomy professor Donald E. Brownlee of the University of Washington in Seattle.

Original Source: NASA News Release

Posted on by Fraser Cain

Spirit Makes a Minor Course Correction

Image credit: NASA/JPL

NASA’s Spirit rover made a slight correction to its trajectory on December 26, when it fired its thrusters for 3.4 seconds. The maneuver went flawlessly, and put the lander right on course to land in Mars’ Gusev Crater on January 4 at 0435 UTC (11:35 pm EST January 3). This was Spirit’s fourth trajectory correction maneuver since its launch on June 10, and two more might still happen in the final days if its flight is a little off-target. As with Beagle 2, the most dangerous part of the mission will happen when the rovers have to pass through Mars atmosphere and land safely on the planet.

NASA’s Spirit rover spacecraft fired its thrusters for 3.4 seconds on Friday, Dec. 26, to make a slight and possibly final correction in its flight path about one week before landing on Mars.

Radio tracking of the spacecraft during the 24 hours after the maneuver showed it to be right on course for its landing inside Mars’ Gusev Crater at 04:35 Jan. 4, 2004, Universal Time (8:35 p.m. Jan. 3, Pacific Standard Time.) Spirit’s twin, Opportunity, will reach Mars three weeks later.

“The maneuver went flawlessly,” said Dr. Mark Adler, Spirit mission manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

This was Spirit’s fourth trajectory correction maneuver since launch on June 10. Two more are on the schedule for the flight’s final three days, if needed. Adler said, “It seems unlikely we’ll have to do a fifth trajectory correction maneuver, but we’ll make the final call Thursday morning after we have a few more days of tracking data. Right now, it looks as though we hit the bull’s-eye.”

The adjustment was a quick nudge approximately perpendicular to the spacecraft’s spin axis, said JPL’s Chris Potts, deputy navigation team chief for the NASA Mars Exploration Rover project. “It moved the arrival time later by 2 seconds and moved the landing point on the surface northeast by about 54 kilometers” (33 miles), Potts said. The engine firing changed the velocity of the spacecraft by only 25 millimeters per second (about one-twentieth of one mile per hour).

For both NASA rovers approaching Mars, the most daunting challenges will be descending through Mars’ atmosphere, landing on the surface, and opening up properly from the enclosed and folded configuration in which the rovers arrive. Most previous Mars landing attempts, by various nations, have failed.

Each rover, if it arrives successfully, will then spend more than a week in a careful sequence of steps before rolling off its lander platform. The rovers’ mission is to examine their landing areas for geological evidence about past environmental conditions. In particular, they will seek evidence about the local history of liquid water, which is key information for assessing whether the sites ever could have been hospitable to life. Opportunity will land halfway around Mars from Spirit.

As of 13:00 Universal Time (6 a.m. PST) on New Year’s Day, Spirit will have traveled 481.9 million kilometers (299.4 million miles) since launch and have will have 5.1 million kilometers (3.2 million miles) left to go. Opportunity will have traveled 411 million kilometers (255 million miles) since its July 7 launch and will have 45 million kilometers (27.9 million miles) to go, with three remaining scheduled opportunities for trajectory correction maneuvers.

JPL, a division of the California Institute of Technology, manages the Mars Exploration Rover project for NASA’s Office of Space Science, 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

Mars Express Changes Its Orbit

Image credit: ESA

The European Space Agency’s Mars Express completed a major orbit maneuver, bringing the spacecraft from an equatorial orbit to a polar orbit around Mars. The spacecraft’s main engine was fired for four minutes. Now that it’s in a polar orbit around Mars, the spacecraft will be able to begin its scientific analysis of Mars, using its MARSIS radar to search up to several kilometres under the surface for reserves of water and ice. Mars Express will fly directly over the Beagle 2 landing site on January 7, 2004 and attempt to communicate with it.

This morning, at 09:00 CET, the first European mission to Mars registered another operational success. The Mars Express flight control team at ESOC prepared and executed another critical manoeuvre, bringing the spacecraft from an equatorial orbit into a polar orbit around Mars.

All commands were transmitted to Mars Express via ESA’s new Deep Space Station in New Norcia, Australia. This morning, the main engine of Mars Express was fired for four minutes to turn the spacecraft into a new direction, at a distance of 188 000 kilometres from Mars and about 160 million kilometres from Earth. On 4 January 2004, this new polar orbit will be reduced even further.

Fascinating ESA science mission ahead
In a polar orbit, Mars Express can now start to prepare its scientific observation mission as planned, working much like an ‘Earth-observation satellite’ but around Mars. From the second half of January 2004, the orbiter’s instruments will be able to scan the atmosphere, the surface and parts of the subsurface structure of Mars with unmatched precision.

The MARSIS radar, for example, will be able to scan as far as four kilometres below the surface, looking for underground water or ice. The High Resolution Stereo Camera will take high-precision pictures of the planet and will begin a comprehensive 3D cartography of Mars. Also, several spectrometers will try to unveil the mysteries of Martian mineralogy and the atmosphere, as well as influences from the solar wind or seasonal changes.

Mars Express closes in on Beagle 2 landing area
The change of orbit by the Mars Express orbiter will allow increasingly closer looks at the Beagle 2 landing site, which measures 31 kilometres by 5 kilometres. In this narrowing polar orbit, the orbiter will fly directly over the landing site at an altitude of 315 kilometres on 7 January 2004, at 13:13 CET. The reduced distance, the ideal angle of overflight and originally foreseen communication interfaces between the ‘mother’ and ‘baby’ will increase the probability of catching signals from the ground.

Ongoing European co-operation and international support
The Mars Express flight control team of ESA in Darmstadt, Germany, is in regular contact with its colleagues of the Beagle 2 team and with NASA ground stations. In addition, ESA receives regular support or offers of support from the Jodrell Bank radio telescope in the UK, Westerborg telescope in the Netherlands, Effelsberg telescope in Germany and Stanford University’s telescope in the USA. ESA is grateful for this spirit of dynamic international co-operation on its first mission to Mars.

Original Source: ESA News Release

Posted on by Fraser Cain

Top Space Stories for 2003

2003 was quite a year for space and astronomy, with the loss of Columbia and Chinese making their first successful human space launch. It was definitely a year of highs and lows. Join Universe Today as we look at the top space stories of the year. In no particular order…

Columbia Disaster
Space exploration is an extremely dangerous business. This lesson was hammered home in 2003 when the space shuttle Columbia broke up above Texas as it was on approach to land in Florida. The lives of seven astronauts were lost in a few firey moments on February 1, 2003. Months of investigation revealed that a chunk of foam fell off the external fuel tank and smashed a hole in the shuttle’s carbon-fibre wing panels. When Columbia was returning to Earth at the end of its mission, the open hole in the wing allowed hot gasses to penetrate the shuttle’s heat protection. The Columbia Accident Investigation board placed the blame on the foam, but said that NASA’s lack of safety allowed the accident to happen in the first place. While NASA is implementing the safety recommendations to get the shuttles flying again, the US administration is said to be planning a bold new program in space.

Columbia Accident Investigation website
http://www.caib.us

Chinese Space Launch
Previously unknown, astronaut Yang Liwei became an instant celebrity on October 15, when he became the first human the Chinese space program sent into space. Liwei was launched from the Jiuquan desert launch site and orbited the Earth only 14 times in 21 hours. Only the United States and Russia have ever been capable of sending humans into space before this year. Riding high on their accomplishments, the normally tight-lipped Chinese revealed more details of their space program this year: additional human launches, a space station, probes to the Moon, and eventually humans on the Moon. NASA was one of the first to congratulate the Chinese on their accomplishment, but some space industry experts believe that this will spur the agency on to a new spirit of competition.

SpaceShipOne Goes Supersonic
The space community was expecting US President George Bush to make some announcement about the future of US space exploration on December 17, the 100th anniversary of the first Wright Brothers flight. He didn’t, but on that day Scaled Composites – an aircraft manufacturer in California – made news with the first rocket test flight of SpaceShipOne; their suborbital rocket plane. The unique-looking aircraft was carried to an altitude of 14,600 metres by the White Knight carrier plane and then released. It fired its hybrid rocket engine and blasted up to an altitude of 20,700 metres; breaking the sound barrier as it went. SpaceShipOne is considered the top contender to win the $10 million X-Prize which will be awarded to the first privately-built suborbital spacecraft which can fly to 100 km.

Scaled Composites website
http://www.scaled.com

Disappearance of Beagle 2
In a perfect world, this would be a tribute to the successful landing of Beagle 2; Britain’s $50 million, 70-kg Mars lander which traveled to the Red Planet on board the European Space Agency’s Mars Express spacecraft. Unfortunately, it looks like Mars has swallowed yet another spacecraft, and at the time of this writing the lander has failed to communicate home; either through Mars Odyssey orbiting above, or Earth-based radio observatories. Beagle 2 was supposed to land in the relatively safe Isidis Planitia region of Mars and then search for evidence of microbial life for 180-days with a suite of sensitive instruments. The best opportunity to communicate with Beagle 2 comes in 2004, though, when Mars Express reaches its final orbit and will attempt to make contact. Maybe the recovery of Beagle 2 will make one of the top stories in 2004.

Beagle 2 website
http://www.beagle2.com

Mars’ Closest Approach to the Earth
Mars took centre stage this summer when it made its closest approach to the Earth in over 60,000 years. Because of their orbits, the Earth and Mars get close every two years, but on August 27 they were only 55,758,000 kilometres apart. The mainstream media picked up the story, and for a while it was Mars mania. Astronomy clubs and planetariums that held special Mars observing nights for the public were totally overwhelmed by the number of people who showed up to have a peek through a telescope. And they weren’t disappointed. Even with a relatively small 6″ telescope and good observing conditions, it was possible to see details on Mars like its polar caps, dust storms, and darker patches. If you missed it this year, don’t worry, Mars will be even closer in 2287.

Biggest Solar Flare Ever Observed
Our Sun showed a nasty side this year, with a series of powerful flares and coronal mass ejections. On November 4, 2003, the Sun surprised even the most experienced solar astronomers with the most powerful flare anyone had ever seen. It was so powerful that it momentarily blinded cameras designed to measure flares, so it actually took a few days for astronomers to calculate just how bright it was. In the end, it was categorized as an X28 flare. But this was just one of a series of powerful flares, many of which were aimed directly at our Earth, sending wave after wave of material our direction. Incredibly, there were very few problems on the Earth – contact was lost with a Japanese satellite, and some communications were disrupted – but we got through it largely unharmed. The auroras, however, were awesome.

SOHO website
http://sohowww.nascom.nasa.gov

Farewell Galileo
On September 20, 2003, NASA’s Galileo spacecraft finally ended its 14-year journey to the Jovian system with its triumphant crash into the giant gas planet. Galileo was plagued with problems right from the start, including a series of launch delays, and a failure of its main antenna. But NASA engineers were able to overcome these obstacles, and use the spacecraft to make some incredible discoveries about the Jupiter and its moons. Photos taken by the Galileo gave scientists proof that three of the moons might have liquid water under their icy surfaces. Passing through Jupiter’s massive radiation took its toll on the spacecraft, and various instruments started to fail, including its main camera, which went offline in 2002. With the spacecraft failing, controllers decided it would be best to crash Galileo into Jupiter, to protect potential life on the Jovian moons from contamination.

Galileo website
http://www2.jpl.nasa.gov/galileo

Age of the Universe
This is the year we learned how old we are – well… how old the Universe is. Thanks to a comprehensive survey of the sky performed by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), astronomers were able to calculate that the Universe is 13.7 billion years old, give or take 200 million years. WMAP, launched in June 2001, measured the sky’s cosmic background radiation, which was unleashed 380,000 years after the Big Bang – when the expanding Universe had cooled down enough for the first atoms to form. This wasn’t the first survey of the cosmic background radiation, but the WMAP is so sensitive, it was able to detect extremely slight temperature changes in the radiation.

Wilkinson Microwave Anistropy Probe website
http://map.gsfc.nasa.gov

Spitzer Space Telescope
The last of great observatories, the Spitzer Space Telescope (previously named SIRTF) was finally launched into space on August 25, 2003. Almost every object in the Universe radiates heat in the infrared spectrum, which Spitzer is designed to detect. So objects which might be hidden to visible light telescopes, like Hubble, can be seen in tremendous detail with Spitzer. The observatory completed its 60-day on-orbit checkout period and calibration, and just before the end of the year the operators released four incredible photographs that demonstrated the potential of this instrument. Spitzer will help astronomers look at the dusty hearts of galaxies, young planetary discs, and cool objects like comets, and brown dwarfs. Spitzer may even help astronomers understand the nature of dark matter.

Spitzer Space Telescope website
http://www.spitzer.caltech.edu

Mars Express Arrives
The search for the missing Beagle 2 lander overshadowed the success of the European Space Agency’s Mars Express spacecraft, which went into a perfect orbit on December 25, and then performed additional maneuvers flawlessly. This is the Europe’s first mission to the Red Planet, and it’s got an important job to do. In addition to helping out the search for Beagle 2, Mars Express will begin mapping the surface of Mars with a powerful radar system which should reveal underground deposits of water and ice.

Mars Express website
http://www.esa.int/SPECIALS/Mars_Express

Posted on by Fraser Cain

Martian Crater Could Have Swallowed Beagle 2

Image credit: Malin

Lord Sainsbury, the UK Minister of Science and Technology reinforced today that they haven’t given up hope on Beagle 2, and continue to be optimistic that the lander will be found. A “tiger team” of engineers and scientists are working through all the scenarios that could help to explain what’s wrong with Beagle 2 (other than it’s all smashed up on the Martian surface). One theory is that the lander might have fallen into a kilometre-sized crater which was in the landing zone; although, the chances of this happening are pretty remote.

The latest attempts to communicate with Beagle 2 via the Lovell Telescope at Jodrell Bank and the Mars Odyssey spacecraft have been unsuccessful. However, the Beagle 2 team has not given up hope and continues to be optimistic that efforts to contact the lander will eventually be successful.

This message was also reinforced by Lord Sainsbury, UK Minister for Science and Innovation, who this morning joined members of the Beagle 2 team to answer questions about the status of the project.

“While we’re disappointed that things have not gone according to plan, we are determined that the search should go on, both the search to make contact with Beagle 2 and also (the search) to answer the long term question about whether there is life on Mars,” said Lord Sainsbury.

“There’s clearly still a good opportunity to make contact with Beagle 2 with Mars Express when it comes into action, and that has to be the first priority at this point. I think everything is being done by the ‘tiger team’ in Leicester to make contact with Beagle 2 and I want to wish them every success in their efforts.”

“We are looking at a number of possible failure modes that we might do something about,” said Dr. Mark Sims, Beagle 2 mission manager from the University of Leicester.

“We are working under the assumption that Beagle 2 is on the surface of Mars and for some reason cannot communicate to us. In particular, we’re looking at two major issues. One is communications, and there are also related timing and software issues.

“We’ve got a few more Odyssey contacts, the last one being on 31 December. Then we have four contacts with Mars Express already pre-programmed into Beagle, assuming the software is running, on 6, 12, 13 and 17. The 6 and 12 are when Mars Express is manoeuvring into its final orbit, so they are not optimum for Beagle 2 communications. The 13th and 17th are very good opportunities for Mars Express.”

According to Dr. Sims, one of the scenarios the team was investigating – a timer and hardware reset – now seems unlikely, and can probably be ruled out. However, other possible slips of the onboard time may have been caused by software or problems of copying data between various parts of memory. Possibly, all of the stored command times have been lost.

“None of these can yet be eliminated,” he said.

After the tenth contact attempt, Beagle 2 will move into communication search mode 1 (CSM 1), taking advantage of the ability of the software on board Beagle 2 to recognise when dawn and dusk occur on Mars by measuring the current feeding from the solar arrays.

“When we get into CSM 1 mode, Beagle 2 will start putting additional contacts on its time line, independent of the clock value,” said Mark Sims. “This will happen after 31 December.”

The team is also looking at sending blind commands to Beagle 2. This is helped by Beagle going into CSM 1 mode.

“The team has come up with a method of fooling the receiver into accepting commands without having to talk back to the orbiter,” said Dr. Sims. “We have an agreement with JPL to reconfigure Odyssey to provisionally attempt this on 31 December, the last programmed Odyssey pass.”

Malin Space Science Systems has also provided the Beagle 2 team with a picture of the landing site taken by the camera on Mars Global Surveyor 20 minutes after the spacecraft’s scheduled touchdown. It shows that the weather was quite good on the day Beagle landed, so it was unlikely to be a factor in the descent. The next opportunity to image the landing site with Mars Global Surveyor will not be until 5 January.

The image showing the centre of Beagle 2’s landing ellipse also shows a 1 km wide crater. There is just an outside possibility that the lander could have touched down inside this crater, resulting in problems caused by steep slopes, large number of rocks or disruption to communication from the lander. This image is now available on the Beagle 2 and PPARC Web sites (see link on the right hand side).

While the Lander Operations Control Centre in Leicester continues its efforts to communicate with the Beagle 2, Lord Sainsbury took the opportunity to inform the media that the UK government is keen to continue the innovative robotic exploration effort begun with the lander.

“Long term we need to be working with ESA to ensure that in some form there is a Beagle 3 which takes forwards this technology,” he said. “I very much hope that the Aurora programme, which is now being developed by ESA, will take forward this kind of robotic exploration.

“We’ve always recognised that Beagle 2 was a high risk project, and we must avoid the temptation in future to only do low risk projects.

“I’d like to use this opportunity to add my thanks to all those helping our efforts to make contact with Beagle 2. I think the amount of international collaboration one gets on these occasions is very, very impressive and very encouraging to the team.”

“We should not ignore the importance of Mars Express, which has three British-designed instruments on board and which looks set for success,” he added.

“Finally, can I use this opportunity to wish the Americans every success with its two Mars Exploration Rovers, Spirit and Opportunity.”

Original Source: PPARC News Release

Posted on by Mark Mortimer

Book Review: Rocket Man

In his newest book, Rocket Man, David Clary took on the challenge of describing the person that was Robert Goddard the father of the rocket program in the United States. Through an excellent chronological depiction of the events and people of Goddard’s life, Mr. Clary presents significant moments and actions in an effort to give a sense of his personality. Mr. Clary acknowledges that he was quite hampered by the efforts of Goddard’s retinue who had filtered and moulded material so as to fit only their desired image. Without giving his own conclusions, Mr. Clary presents a very readable passage on Goddard’s life.

The image that Mr Clary portrays is of a very bright and capable man who accomplished amazing feats yet whose personality might have been as much a hindrance to achieving space travel as it was in driving it forward. Paramount in this was Goddard’s belief that rocketry was his and only his domain. Parties showing any interest in helping technically were considered interlopers or trespassers and dealt with disparagingly. The advantage of this was that there was one focal point for rocketry in the United States. The detriment to this was that Goddard had to become a specialist in many related fields such as chemistry (e.g. obtaining liquid oxygen) and metallurgy (e.g. constructing nozzles and chambers) and also disparate fields such as publicity and marketing. It seems that by spreading himself across all this activities and protecting his fiefdom meant Goddard was unable to progress on those tasks which his natural abilities favoured.

There were two other consequences to being this type of generalist. One is that Goddard treated the activities as a hobbyist. For example, Mr Clary describes Goddard as wanting his office by his men in the machinist’s shop where Goddard would build mock ups by hand soldering tin cans and metal pieces. The other consequence is that Goddard seemed incapable of setting an achievable goal and then preparing a path to reach this goal. Much can be argued that this is typical whenever a person is at the forefront of a new field and is trying to advance it. However getting support for his project without clearly showing either plans or progress appears to have alienated potential supporters. Nevertheless, Mr. Clary does note that “Goddard had received more money for his research than any other civilian scientist for a single project before World War II ” And considering much of this was granted during the worldwide depression of the 1920’s, this is no small feat.

This book does give a glimpse of the person that was Robert Goddard. By listing many of the significant events of his life the reader can draw an impression of who this man was. However, as Clary clearly acknowledges, so much of the available information regarding Goddard has been purposely manipulated that Goddard the man is difficult to pinpoint. In consequence, Mr. Clary’s writing reads like a list of events woven together with text. Further, this joining text drifts and can seem a bit superfluous at times. Yet, the reader does get a flavour of who the rocket man was and especially of the challenges they faced.

Note that this book describes the man. There is little information on Goddard’s technical activities however it does have many references to publication with this information.

Rocket Man is an enjoyable read and will tell you something of Goddard and much of his trials and tribulations he faced as he pushed forward the new field of rocketry. Upon finishing the book, I couldn’t help but see a similarity between Goddard, his rocket Nell and his supporters the Guggenheims with today’s Burt Rutan, his vehicle SpaceShipOne and his supporter Paul Allen. I hope their visions come to fruition in a more auspicious manner than that of Goddard’s.

Review by Mark Mortimer

More Information: Amazon.com

Posted on by Fraser Cain

Young Gas Giants Have to Fight to Survive

Image credit: ESA

Planet hunters have found more than 30 stars with gas giants in a tight orbit. This orbit seems to be caused by a race between a young gas giant and the star’s planetary disk during early formation of the star system. It’s too hot for them to form in their tight orbit; instead it’s believed they’re formed further out and then slowly pushed into the star by material in the new star system. In some cases the planet is gobbled up by the star, while sometimes the planet consumes the early planetary disk of material and survives.

Of the first 100 stars found to harbor planets, more than 30 stars host a Jupiter-sized world in an orbit smaller than Mercury’s, whizzing around its star in a matter of days (as opposed to our solar system where Jupiter takes 12 years to orbit the Sun). Such close orbits result from a race between a nascent gas giant and a newborn star. In the October 10, 2003, issue of The Astrophysical Journal Letters, astronomers Myron Lecar and Dimitar Sasselov showed what influences this race. They found that planet formation is a contest, where a growing planet must fight for survival lest it be swallowed by the star that initially nurtured it.

“The endgame is a race between the star and its giant planet,” says Sasselov. “In some systems, the planet wins and survives, but in other systems, the planet loses the race and is eaten by the star.”

Although Jupiter-sized worlds have been found orbiting incredibly close to their parent stars, such giant planets could not have formed in their current locations. The oven-like heat of the nearby star and dearth of raw materials would have prevented any large planet from coalescing. “It’s a lousy neighborhood to form gas giants,” says Lecar. “But we find a lot of Jupiter-sized planets in such neighborhoods. Explaining how they got there is a challenge.”

Theorists calculate that so-called “hot Jupiters” must form farther out in the disk of gas and dust surrounding the new star and then migrate inward. A challenge is to halt the planet’s migration before it spirals into the star.

A Jupiter-like world’s migration is powered by the disk material outside the planet’s orbit. The outer protoplanetary disk inexorably pushes the planet inward, even as the planet grows by accreting that outer material. Lecar and Sasselov showed that a planet can win its race to avoid destruction by eating the outer disk before the star eats it.

Our solar system differs from the “hot Jupiter” systems in that the race must have ended quite early. Jupiter migrated for only a short distance before consuming the material between it and the infant Saturn, bringing the King of Planets to a halt. If the protoplanetary disk that birthed our solar system had contained more matter, Jupiter might have lost the race. Then it and the inner planets, including Earth, would have spiraled into the Sun.

“If Jupiter goes, they all go,” says Lecar.

“It’s too early to say that our solar system is rare, because it’s easier to find ‘hot Jupiter’ systems with current detection techniques,” says Sasselov. “But we certainly can say we’re fortunate that Jupiter’s migration stopped early. Otherwise, the Earth would have been destroyed, leaving a barren solar system devoid of life.”

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: Harvard CfA News Release

Posted on by Fraser Cain

First Double Star Launched

Image credit: ESA

The first of two Double Star satellites was successfully launched Monday on board a Chinese Long March 2C rocket. The satellite, called TC-1, was launched from the Chinese space port at Xichang into an equatorial orbit, and the second satellite, TC-2 will launch next into a polar orbit. The two satellites will work with the previously-launched Cluster satellites to study the effect of the Sun on the Earth’s atmosphere and magnetosphere. The European Space Agency supplied 8 scientific instruments for the satellite.

This evening, the Chinese National Space Administration (CNSA) successfully launched TC-1, the first of two scientific satellites known as Double Star.

The spacecraft, called ‘Tan Ce 1’ which in Chinese means ‘Explorer 1,’ took off from the Chinese launch base in Xichang, in Sichuan province, on board a Long March 2C launcher.

ESA has contributed to the Double Star mission by providing eight on-board scientific instruments. Double Star follows the footsteps of ESA’s Cluster mission and will study closely the interaction between the solar wind and the Earth’s magnetic field.

The People’s Republic of China and ESA have a long history of scientific collaboration. The first co-operation agreement was signed in 1980, to facilitate the exchange of scientific information. Thirteen years later, the collaboration focused on a specific mission, ESA’s Cluster, to study the Earth’s magnetosphere. Then, in 1997, the CNSA invited ESA to participate in Double Star, a two-satellite mission to study the Earth’s magnetic field, but from a perspective which is different from that of Cluster and complementary to it.

An agreement to develop this joint mission was signed on 9 July 2001 by ESA’s Director General, Antonio Rodota, and Luan Enjie, Administrator of the CNSA.

ESA’s contribution to the mission includes eight scientific instruments, of which seven are spares from the Cluster mission, and support to the ground segment for four hours each day via ESA’s satellite tracking station in Villafranca, Spain.

Today’s launch sees the culmination of these joint efforts and marks another important step in the collaboration between CNSA and ESA. The instruments on board Double Star are the first ever European ones to be flown on a Chinese satellite. Together with those built by Chinese scientists, they will work in synergy with those mounted on board the four Cluster spacecraft.

The positions and orbit of the two Double Star satellites have been carefully defined to allow the study of the magnetosphere on a larger scale than that possible with Cluster alone. An example of this co-ordinated activity is the study of the substorms producing the bright aurorae.

The exact region where they form is still unclear but the simultaneous high-resolution measurements to be made by Double Star and Cluster are expected to give an answer.

Professor David Southwood, the Director of ESA’s Scientific Programme, said: “Double Star is a win-win project. Not only will European scientists participate in a new mission, at a very low cost, but they will also see an increased scientific return from the four ESA Cluster satellites. Chinese scientists will equally benefit of this, since they already participate in the Cluster mission. These are the great advantages of an historic international collaboration.”

Original Source: ESA News Release

Posted on by Fraser Cain

Soyuz Launches Israeli Satellite

Image credit: Arianespace

A Soyuz rocket with a Fregat upper stage successfully launched Israel’s AMOS 2 telecommunications satellite on Saturday. The launch occurred at 2130 UTC (4:30 pm EST) from the Baikonur Cosmodrome, and was jointly managed by Arianespace and Starsem. AMOS 2 will supply the Middle East, Europe and Eastern US with satellite broadcasting. This was the 1,684th mission for the Soyuz family of vehicles.

The 1,684th launch of a Soyuz family rocket (using the Soyuz-Fregat version) took place at the Baikonur Cosmodrome in Kazakhstan. The launcher lifted off as scheduled at 2:30 a.m. local time on December 28 (i.e. 21:30 UTC on Saturday December 27, 10:30 p.m. Paris time on December 27).

Starsem, Arianespace and their Russian partners confirmed that the Fregat upper stage accurately injected the Amos 2 satellite into the targeted orbit. This was the Soyuz launcher’s first geostationary transfer orbit (GTO) mission. Three successive burns of the Fregat upper stage were performed to inject the Amos 2 spacecraft on its transfer orbit 6 hours and 45 minutes after lift-off.

To comply with Israel Aircraft Industries’ (IAI) requirements, Arianespace and Starsem had decided, in agreement with Israeli operator, Spacecom Ltd., that the Amos 2 spacecraft launch, initially planned by an Ariane 5, would be performed by a Soyuz launch vehicle. This decision reflects the policy set up by Arianespace and Starsem to meet customers’ needs, providing enhanced flexibility based on a family of launch vehicles.

Today’s launch was also the 12th carried out by Starsem, which is responsible for international marketing of the Soyuz launcher, as well as for its operation. Starsem’s shareholders are Arianespace, EADS, the Russian Aviation and Space Agency and the Samara Space Center.

The new successful Soyuz launch clearly reflects the industrial capabilities of the Samara Space Center as well as the availability of the Russian teams in charge of Soyuz operation, managed by the Russian Aviation and Space Agency.

In 1996, Arianespace had already launched the first Israeli communications satellite, Amos 1. Co-located with Amos 1, at 4 degrees West over the Gulf of Guinea, Amos 2 will provide additional high-power transmission capacity for Europe, the Middle East and the East Coast of the United States. The satellite was designed and built by MBT Space Division of IAI. Weighing 1,374 kg at liftoff and equipped with 14 transponders, Amos 2 will be operated by Spacecom Ltd.

Original Source: Arianespace News Release

Posted on by Fraser Cain

Mars Express is Orbiting Safely

Image credit: ESA

Unlike its missing passenger, Beagle 2, controllers from the European Space Agency know exactly where Mars Express is – exactly where they want it. The spacecraft is currently on a wide equatorial orbit which brings it as close as 400 km and then out to 188,000 km away from the planet. Engineers are preparing the spacecraft for a further burn of its main engine which will bring the spacecraft into a closer polar orbit around Mars. Once Mars Express modifies its orbit, it will be the best candidate to communicate with the missing Beagle 2; starting January 4, 2004.

The Mars Express orbiter, mothership of Europe’s first mission to the Red Planet, is in a stable and precise orbit around Mars.

The essential Mars Orbit Insertion (MOI) manoeuvre had been completed on 25 December at 3:47 CET. This brought the spacecraft as close as 400 kilometres to the surface of Mars.

Afterwards, the spacecraft went into a highly elliptical orbit, going as far as 188 000 kilometres away from the planet. The most essential part of the Mars Express mission is performing very well and we are expecting exciting science from January 2004 onwards.

Today, 27 December, the mission control team at ESOC prepared the next steps to turn Mars Express from a near-equatorial orbit into a polar orbit. Michael McKay, Mars Express Flight Director explained, “Our flight dynamics and flight operations teams thoroughly discuss, evaluate and prepare the commands to perform a series of manoeuvres starting with a major move on 30 December – where we will fire the main engine again for three minutes.

“These key manoeuvres will allow us to get even closer to Mars. They will not only allow us more frequent ‘overflights’ of the Beagle 2 landing area, but also ensure the beginning of the orbiter’s science mission. As Mars Express is the planned main communication partner of the Beagle 2, the chances of obtaining a signal strongly increase with these manoeuvres after 4 January 2004.”

Close European and international co-operation
The ESA control team at ESOC are in regular contact with their colleagues of the Beagle 2 team and the Jodrell Bank telescope in the UK, with NASA ground stations and with several other European partners (UK, Germany, Netherlands, etc.). Many international offers have been forthcoming to support the search for the Beagle 2 lander.

Original Source: ESA News Release