February 27, 2007, 8:45 PM CT

Successful Rosetta swing

The European Space Agency's (ESA) Rosetta spacecraft successfully completed a swing-by of Mars in the early hours of Sunday morning (25th February 2007). Not only did this mark an important milestone on the spacecraft's 7.1 billion km journey to comet Churyumov Gerasimenko but it provided a unique opportunity to gather further scientific data and images from the Red Planet.

INTA/UPM/DASP/IDAThe critical gravity assist manoeuvre around Mars has helped Rosetta change direction putting it on the correct track towards Earth its next destination planet whose gravitational energy Rosetta will exploit in November this year to gain acceleration and continue on its ten-year journey to the comet which it will reach in 2014.

At 2.57 GMT mission controllers at ESA's Space Operations Centre (ESOC) in Germany confirmed that Rosetta had successfully completed the swing-by manoeuvre. At its closest approach (around 2.15 GMT) Rosetta passed the surface of Mars at a distance of 250 km (155 miles) travelling at a mere 10.1 km/second relative to the centre of the planet.

During the swing by there was a 25 minute period when Rosetta passed into the shadow of Mars denying the probe the ability to generate power using its solar arrays. At this time the spacecraft was put into "eclipse mode" with no science operations taking place on the orbiter instruments......... Posted by: Brooke      Read more         Source

February 20, 2007, 8:59 PM CT

Our View Of The Gamma-ray Sky

Integral's latest survey of the gamma-ray universe continues to change the way astronomers think of the high-energy cosmos. With over seventy percent of the sky now observed by Integral, astronomers have been able to construct the largest catalogue yet of individual gamma-ray-emitting celestial objects. And there is no end in sight for the discoveries.

Integral is the European Space Agency's latest orbiting gamma-ray observatory. Ever since Integral began scientific operations in 2003, the project team has been devoting a substantial proportion of its observing time to a survey of the gamma-ray universe.

"The gamma-ray sky is notoriously variable and extremely unpredictable," says Anthony Dean, University of Southampton, UK, one of the original proposers of the Integral mission. Hence, the need for Integral's constant vigilance and an accurate catalogue of all gamma-ray sources. With this, astronomers can target individual gamma-ray objects for more detailed, study.

For the past three and a half years, Integral has been collecting survey data. At the end of every year, the data has been turned into a catalogue of sources.

During the first year, it concentrated on the regions close to the centre of our galaxy and found more than 120 sources. During the following year, Integral broadened its reach and found almost 100 more sources......... Posted by: Brooke      Read more         Source

February 20, 2007, 8:42 PM CT

Ulysses scores a hat-trick

ESA-NASA Ulysses mission has marked another high point in its mission. For the third time in a long and highly successful career, Ulysses has reached its maximum south solar latitude of 80 degrees as it flies over the Sun's southern polar cap.

Launched in 1990, the European-built spacecraft visits both polar regions once every 6.2 years as it circles the Sun in an orbit that is almost perpendicular to the ecliptic, the plane in which the Earth and the planets move.

Although originally designed for a mission lasting 5 years, the Ulysses space probe and its suite of 9 scientific experiments are still going strong after more than 16 years in orbit.

Operating the spacecraft has become more demanding over the years, however, as one consequence of the mission's longevity is a decrease in the electrical power available on board. "Ulysses uses a Radioisotope Thermoelectric Generator, or RTG for short, to generate the electricity needed for the spacecraft subsystems and science instruments", said Nigel Angold, ESA's Mission Operations Manager for Ulysses.

The RTG converts the heat produced by radioactive decay of its fuel into electrical power. "As a result of the decay process, the RTG output decreases with time", said Angold. In recent years, this has necessitated sharing the available power among the science instruments in such a way that key instruments are kept on permanently, while others are operated only part of the time......... Posted by: Brooke      Read more         Source

February 19, 2007, 8:26 PM CT

All Set For Mars Swing-by

UK scientists from 10 institutions are involved in the instruments on both the Rosetta orbiter and lander some of which will be operating during the flyby. UK industry is also heavily involved in the mission, having provided key components, including the mission control system (SciSys UK Ltd) and the orbit control and propulsion system (EADS Astrium, UK). SciSys staff will be closely monitoring events at ESA's European Space Operations Centre (ESOC) in Germany where the manoeuvre is being co-ordinated.

Launched in March 2004 the three tonne spacecraft could not be sent on its correct trajectory by the launcher and so on its journey it will make a series of planned gravity assist manoeuvres past the Earth and Mars.

Professor Keith Mason, Chief Executive of PPARC said, "With Rosetta now 3 years into its epic 10 year journey this flyby is an important milestone for the spacecraft. Not only will it help set it on its correct path but it provides a further opportunity to find out more about Mars from a different perspective".

Rosetta's closest approach to Mars will be made at 0153 GMT on 25th February 2007, 1090 days since launch.The distance from Rosetta to the surface of Mars will be around 250 km, and at its closest approach the spacecraft will be travelling at around 10.1 km/s (~36,400 kph ~22,700 mph) relative to the centre of Mars......... Posted by: Brooke      Read more         Source

February 12, 2007, 8:52 PM CT

Suborbital Sounding Rocket Launched

Marc Lessard of the physics department at the University of New Hampshire was the principle investigator for the experiment to investigate various aspects of pulsating aurora. The 662 pound experiment housed in the nose cone of a 65-foot Black Brant XII rocket arced above the atmosphere 408 miles above northern Alaska. Pulsating aurora is a subtle type of aurora that seems to blink on and off in large round patches.

Lessard's experiment, called ROPA (Rocket Observations of Pulsating Aurora), was complex even by rocket-science standards. It had a main instrument cluster, known as a payload, and three sub-payloads, which separated early after the rocket cleared the upper atmosphere at an altitude of 140 miles. Two of the sub-payloads had their own rocket motors, propelling them away from the main payload where they obtained measurements of the pulsating aurora, which occurred near the latitude of Toolik Lake on Alaska's North Slope. Dirk Lummerzheim of the University of Alaska Fairbanks' Geophysical Institute was on the ground at Toolik Lake. During the launch, he identified what looked like pulsating aurora in the all-sky camera at the research station there.

This morning, a NASA suborbital sounding rocket launched from Poker Flat Research Range into an aurora display over northern Alaska at 3:45 a.m. Alaska Standard Time, allowing researchers to gather more data about the power source behind pulsating auroras......... Posted by: Brooke      Read more         Source

February 8, 2007, 9:53 PM CT

Closest Gravitational Lensing Galaxy

A giant elliptical galaxy seen in an image from the Hubble Space Telescope is the closest gravitational lens yet known, according to information released by the Hubble Heritage Project.

John Blakeslee, an assistant professor with the Department of Physics and Astronomy at Washington State University, working with colleagues from the University of Hawaii and the University of Durham in England, targeted the galaxy for a closer look by Hubble.

"The galaxy was well-known, but the Hubble images reveal so much more detail about it, including the unexpected finding that it's the nearest gravitational lens," said Blakeslee.

A gravitational lens is a celestial object so huge that it has enough mass to deflect, magnify and focus light emitted by an object that is on the opposite side of it from Earth. The result is that when viewed from Earth, the more distant object appears as an arc or ring rather than a spot or spiral. Such images are known as "Einstein rings" because Albert Einstein first predicted them.

Despite the huge number of galaxies in the universe, said Blakeslee, "gravitational lensing is a rare occurrence because it requires an almost perfect alignment of a distant galaxy with an intervening one that has enough mass to gravitationally focus the light".........

Posted by: Brooke      Read more         Source

February 4, 2007, 8:23 PM CT

Sophisticated ESA space weather tool

If a satellite encounters high-energy particles or other 'space weather' phenomena before ground controllers can take action, on-board electronics could be disrupted, scientific instruments damaged and, in very rare and extreme cases, spacecraft may even be lost. A sophisticated tool in development at ESOC promises to provide effective monitoring and forecasting for any type of mission.

But since early 2005, SEISOP (Space Environment Information System for Operations), a space-weather monitoring and forecasting tool under development at ESA's Space Operations Centre, has been successfully providing near-real-time space weather reports for Integral, ESA's gamma-ray space observatory.

Solar activity influences the entire solar system in several ways, including generating streams of fast-moving energetic particles and sudden bursts of damaging X-rays during solar flares.

Energetic cosmic rays from elsewhere in the galaxy also penetrate into our solar system. These phenomena are some of the major sources of abnormal behaviour and aging for spacecraft and their sensitive scientific instruments.

"SEISOP can potentially provide warning services to space agencies worldwide, since space weather can affect any spacecraft."

Space Weather affects spacecraft in a number of ways.........

Posted by: Tyler      Read more         Source

January 30, 2007, 4:43 AM CT

Hot Stuff On Saturn

UCL scientists have reported findings in the journal 'Nature' that rule out a long-held theory about why the Gas Giants like Saturn have such hot outer atmospheres.

Along with colleagues from Boston University, the team from UCL Physics & Astronomy observed that the upper atmospheres of the giant planets in our solar system do not heat up in the same way as here on Earth.

A simple calculation to give the expected temperature of a planet's upper atmosphere balances the amount of sunlight absorbed by the energy lost to the lower atmosphere. However, the calculated values don't tally with the actual observations of the gas giants - they are consistently much hotter.It has long been thought that the culprit behind the heating process was the ionosphere, being driven by the planet's magnetic field, or magnetosphere. On the Earth this is seen in the auroral region where the spectacular Aurora Borealis, or Northen Lights, show where this energy transfer is taking place.

By analogy, it was believed the heating effect on the gas giants would be similar. The 'auroral zone' heating would then somehow be distributed to lower latitudes, though this is difficult to do because the high spin rates of these planets tends to prevent north-south movement.

The UCL team was investigating this redistribution when they reached their surprising conclusion. By using numerical models of Saturn's atmosphere, the scientists observed that there, the net effects of the winds driven by polar energy inputs is not to heat the atmosphere, but to actually cool it equatorward of the heated region.........

Posted by: Brooke      Read more         Source

January 24, 2007, 6:43 PM CT

Corot Sees First Light!

In the night between 17 and 18 January 2007, the protective cover of the COROT telescope has been successfully opened, and COROT has seen for the first time light coming from stars.

Surveying vast stellar fields to learn about star interiors and to search for extra-solar planets is the goal of this unique mission, whose scientific observations will officially start at the beginning of February this year.

The first light detected by COROT comes from the constellation of the Unicorn near Orion, the great 'hunter' whose imposing silhouette stands out in the winter nights. This nice image, taken during the in-orbit calibration exercise, shows that the quality of this preliminary data is basically as good as the computer simulations. "This is an excellent piece of news," commented Malcolm Fridlund, ESA Project Scientist for COROT.

On 18 January, the telescope was carefully aligned with the region to be observed, facing away from the centre of our Galaxy. This setting that will be maintained until April, when the Sun's rays will start to interfere with the observations.

COROT will then rotate by 180 degrees and will start observing the opposite region towards the centre of the Milky Way. In the meantime the COROT scientists are preparing for the science phase to start in February, continuing a thorough examination of the data and the information collected so far.........

Posted by: Brooke      Read more         Source

January 15, 2007, 7:21 PM CT

A Year Of Extraterrestrial Fountains And Flows

The past year was extraordinary for the discovery of extraterrestrial fountains and flows -- some offering new potential in the search for liquid water and the origin of life beyond planet Earth. Increased evidence was uncovered that fountains spurt not only from Saturn's moon Enceladus, but from the dunes of Mars as well. Lakes were found on Saturn's moon Titan, and the residual of a flowing liquid was discovered on the walls of Martian craters.

The diverse Solar System fluidity may involve forms of slushy water-ice, methane, or sublimating carbon dioxide. Pictured above, the light-colored path below the image center is hypothesized to have been created sometime in just the past few years by liquid water flowing across the surface of Mars.........

Posted by: Brooke      Read more