Posted on by Fraser Cain

Mars Express Lowers Its Orbit Again

Image credit: ESA

The European Space Agency’s Mars Express performed another five minute burn of its engine to change its orbit around the Red Planet. The lowest point of its orbit is now 250 km, and the high point is 40,000 km. Two more maneuvers are scheduled which will bring the spacecraft down to its final orbit by January 11. Mars Express will be in position to help search for Beagle 2 very soon. Teams from Beagle 2 and Mars Express are working through various scenarios that could explain why the lander went missing.

Today at 14:13 CET, ESA?s Mars Express spacecraft successfully executed an essential planned manoeuvre to reduce its orbit around the Red Planet.

A five-minute burn of its main engine brought Mars Express from an orbit apocentre (highest point) of 190 000 kilometres to 40 000 kilometres with a pericentre (lowest point) of about 250 kilometres.

Mars Express will reach its final operational orbit of about 11 000 kilometres by 300 kilometres towards the end of the month after two more scheduled orbit adjustments (using main engine burns) on the nights of 6/7 and 10/11 January.

Today?s key move enables ESA to pursue its Mars mission as planned. First, scheduled scientific observations can begin mid-January and, second, the search for the Beagle 2 lander will become much more accurate.

Michael McKay, Mars Express Deputy Flight Director in Darmstadt, Germany, said: ?From the second half of January 2004, the orbiter’s instruments will be prepared to scan the atmosphere, the surface and parts of the subsurface structure of Mars with unprecedented precision.

“The High Resolution Stereo Camera, for example, will take high-precision pictures of the planet and will begin a comprehensive 3D cartography of Mars. The MARSIS radar will be able to scan as far as four kilometres below the surface, looking for underground water or ice.

“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.?

On 7 January 2004, at 13:15 CET, the lowest point of the Mars Express flight path will be as close as 315 kilometres to the landing area of the still-silent Beagle 2.

The NASA Mars Odyssey orbiter and several radio telescopes on Earth have been unable to obtain a signal since Christmas, but chances will rise with the approach of the ‘mothership’ to its ‘baby’ Beagle 2.

Mars Express and Beagle 2 are the only end-to-end tested systems, giving ESA more confidence of establishing contact with the lander.

Today, 4 January, ESA specialists are meeting with Beagle 2 staff at ESA?s European Space Operations Centre in Darmstadt to define a strategy for modes of interaction between the ESA orbiter and the lander.

Mars Express has Ultra High Frequency (UHF) receivers ready to communicate with Beagle 2. Mars Express Project Manager Rudolf Schmidt and his ESA colleagues are very much looking forward to 7 January 2004.

Dr Schmidt said: ?At this precise time, our Mars Express orbiter is in both an ideal flight path and an ideal communication configuration, right on top of the Beagle 2 landing area, at about 86 degrees. In this situation, we should be able to discern the slightest beep from the Martian surface.?

Today?s manoeuvre was another step towards the European exploration of Mars, ensuring both orbiter operations as planned and a precise search of the Beagle 2 lander. ESA is looking forward to an exciting Mars exploration in the next months. The latest news will be posted, as always, at: at http://mars.esa.int

Original Source: ESA News Release

Posted on by Fraser Cain

Spirit Gets Ready to Explore

Image credit: NASA/JPL

With Spirit safely on the surface of Mars, engineers at NASA are starting to get a sense of the environment around it. So far, it looks like the rover couldn’t have landed in a better spot. The platform holding the rover is only tilted a few degrees, and there are no large rocks blocking the ramps. The terrain has lots of rocks to examine, but they’re well spaced out, which should let Spirit travel at a fairly high speed across the ground. Spirit will remain on the landing platform for another nine days or so before it ventures out onto search the area for evidence of past water.

NASA’s Spirit Rover is starting to examine its new surroundings, revealing a vast flatland well suited to the robot’s unprecedented mobility and scientific toolkit.

“Spirit has told us that it is healthy,” Jennifer Trosper of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., said today. Trosper is Spirit mission manager for operations on Mars’ surface. The rover remains perched on its lander platform, and the next nine days or more will be spent preparing for egress, or rolling off, onto the martian surface.

With only two degrees of tilt, with the deck toward the front an average of only about 37 centimeters (15 inches) off the ground, and with apparently no large rocks blocking the way, the lander is in good position for egress. “The egress path we’re working toward is straight ahead,” Trosper said.

The rover’s initial images excited scientists about the prospects of exploring the region after the roll-off.

“My hat is off to the navigation team because they did a fantastic job of getting us right where we wanted to be,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science payload. By correlating images taken by Spirit with earlier images from spacecraft orbiting Mars, the mission team has determined that the rover appears to be in a region marked with numerous swaths where dust devils have removed brighter dust and left darker gravel behind.

“This is our new neighborhood,” Squyres said. “We hit the sweet spot. We wanted someplace where the wind had cleared off the rocks for us. We’ve landed in a place that’s so thick with dust devil tracks that a lot of the dust has been blown away.”

The terrain looks different from any of the sites examined by NASA’s three previous successful landers — the two Vikings in 1976 and Mars Pathfinder in 1997.

“What we’re seeing is a section of surface that is remarkably devoid of big boulders, at least in our immediate vicinity, and that’s good news because big boulders are something we would have trouble driving over,” Squyres said. “We see a rock population that is different from anything we’ve seen elsewhere on Mars, and it comes out very much in our favor.”

Spirit arrived at Mars Jan. 3 (EST and PST; Jan. 4 Universal Time) after a seven month journey. Its task is to spend the next three months exploring for clues in rocks and soil about whether the past environment at this part of Mars was ever watery and suitable to sustain life.

Spirit’s twin Mars Exploration Rover, Opportunity, will reach its landing site on the opposite side of Mars on Jan. 25 (EST and Universal Time; Jan. 24 PST) to begin a similar examination of a site on the opposite side of the planet from Gusev Crater.

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 at: http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Stardust Sweeps Past Comet Wild 2

Image credit: NASA/JPL

The Stardust spacecraft made history today when it passed through the tail of Comet Wild-2, and took some of the best pictures of a comet ever seen. During the flyby, Stardust got within only 230 kilometers of the comet’s nucleus, and captured just a few grams of particles from Wild-2’s tail. The collected particles, which are stored in a sample return capsule, will be brought back to Earth in 2006; it’ll touchdown at a US Air Force testing range in Utah.

Team Stardust, NASA’s first dedicated sample return mission to a comet, passed a huge milestone today by successfully navigating through the particle and gas-laden coma around comet Wild 2 (pronounced “Vilt-2”). During the hazardous traverse, the spacecraft flew within about 230 kilometers (143 miles) of the comet, catching samples of comet particles and scoring detailed pictures of Wild 2’s pockmarked surface.

Closest approach was at about 19:22 Universal Time (11:22 a.m. Pacific Standard Time). The spacecraft’s radio signal was received on Earth 21 minutes and 40 seconds later, at 11:44 a.m. PST.

“Things couldn’t have worked better in a fairy tale,” said Tom Duxbury, Stardust project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

“These images are better than we had hoped for in our wildest dreams,” said Ray Newburn of JPL, a co-investigator for Stardust. “They will help us better understand the mechanisms that drive conditions on comets.”

“These are the best pictures ever taken of a comet,” said Principal Investigator Dr. Don Brownlee of the University of Washington, Seattle. “Although Stardust was designed to be a comet sample return mission, the fantastic details shown in these images greatly exceed our expectations.”

The collected particles, stowed in a sample return capsule onboard Stardust, will be returned to Earth for in-depth analysis. That dramatic event will occur on January 15, 2006, when the capsule makes a soft landing at the U.S. Air Force Utah Test and Training Range. The microscopic particle samples of comet and interstellar dust collected by Stardust will be taken to the planetary material curatorial facility at NASA’s Johnson Space Center, Houston, Texas, for analysis.

Stardust has traveled about 3.22 billion kilometers (2 billion miles) since its launch on February 7, 1999. As it closed the final gap with its cometary quarry, it endured a bombardment of particles surrounding the nucleus of comet Wild 2. To protect Stardust against the blast of expected cometary particles and rocks, the spacecraft rotated so it was flying in the shadow of its “Whipple Shields.” The shields are named for American astronomer Dr. Fred L. Whipple, who, in the 1950s, came up with the idea of shielding spacecraft from high-speed collisions with the 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 shield is built around composite panels designed to disperse particles as they impact, augmented by blankets of a ceramic cloth called Nextel that further dissipate and spread particle debris.

“Everything occurred pretty much to the minute,” said Duxbury. “And with our cometary encounter complete, we invite everybody to tune in about one million, 71 thousand minutes from now when Stardust returns to Earth, bringing with it the first comet samples in the history of space exploration.”

Scientists believe in-depth terrestrial analysis of the samples will reveal much about comets and the earliest history of the solar system. Chemical and physical information locked within the cometary particles could be the record of the formation of the planets and the materials from which they were made. More information on the Stardust mission is available at http://stardust.jpl.nasa.gov .

Stardust, a part of NASA’s Discovery Program of low-cost, highly focused science missions, was built by Lockheed Martin Space Systems, Denver, Colo., and is managed by JPL for NASA’s Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Success! Spirit Lands Safely on Mars

Image credit: NASA/JPL

NASA controllers confirmed that the Spirit rover successfully landed on Mars today. The spacecraft passed through the atmosphere, deployed its parachute, fired its retrorockets, and then bounced along the Martian surface protected by airbags – its landing time was January 4 at 0435 UTC (11:35 pm EST January 3). Pictures from the Martian surface are expected soon. Spirit will spend at least 90 days traveling around the surface of Mars, searching for evidence of past water with several scientific instruments. The next rover, Opportunity, is expected to land on January 24.

A traveling robotic geologist from NASA has landed on Mars and returned stunning images of the area around its landing site in Gusev Crater.

Mars Exploration Rover Spirit successfully sent a radio signal after the spacecraft had bounced and rolled for several minutes following its initial impact at 11:35 p.m. EST (8:35 p.m. Pacific Standard Time) on January 3.

“This is a big night for NASA,” said NASA Administrator Sean O’Keefe. “We’re back. I am very, very proud of this team, and we’re on Mars.”

Members of the mission’s flight team at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., cheered and clapped when they learned that NASA’s Deep Space Network had received a post-landing signal from Spirit. The cheering resumed about three hours later when the rover transmitted its first images to Earth, relaying them through NASA’s Mars Odyssey orbiter.

“We’ve got many steps to go before this mission is over, but we’ve retired a lot of risk with this landing,” said JPL’s Pete Theisinger, project manager for the Mars Exploration Rover Project.

Deputy project manager for the rovers, JPL’s Richard Cook, said, “We’re certainly looking forward to Opportunity landing three weeks from now.” Opportunity is Spirit’s twin rover, headed for the opposite side of Mars.

Dr. Charles Elachi, JPL director, said, “To achieve this mission, we have assembled the best team of young women and men this country can put together. Essential work was done by other NASA centers and by our industrial and academic partners.

Spirit stopped rolling with its base petal down, though that favorable position could change as airbags deflate, said JPL’s Rob Manning, development manager for the rover’s descent through Mars’ atmosphere and landing on the surface.

NASA chose Spirit’s landing site, within Gusev Crater, based on evidence from Mars orbiters that this crater may have held a lake long ago. A long, deep valley, apparently carved by ancient flows of water, leads into Gusev. The crater itself is basin the size of Connecticut created by an asteroid or comet impact early in Mars’ history. Spirit’s task is to spend the next three months exploring for clues in rocks and soil about whether the past environment at this part of Mars was ever watery and suitable to sustain life.

Spirit traveled 487 million kilometers (302.6 million) miles to reach Mars after its launch from Cape Canaveral Air Force Station, Fla., on June 10, 2003. Its twin, Mars Exploration Rover Opportunity, was launched July 7, 2003, and is on course for a landing on the opposite side of Mars on Jan. 25 (Universal Time and EST; 9:05 p.m. on Jan. 24, PST).

The flight team expects to spend more than a week directing Spirit through a series of steps in unfolding, standing up and other preparations necessary before the rover rolls off of its lander platform to get its wheels onto the ground. Meanwhile, Spirit’s cameras and a mineral-identifying infrared instrument will begin examining the surrounding terrain. That information will help engineers and scientists decide which direction to send the rover first.

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 , www.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

Get Set for Spirit

When Pathfinder arrived at Mars back in 1997, I kept a tiny video window open on my desktop to watch every moment of the mission – all thanks to the Internet. It was pretty choppy at times, so hopefully NASA has more bandwidth this time.

Spirit is expected to arrive in Gusev Crater on Mars on January 4 at 0435 UTC (11:35 pm EST, 8:35 pm PST January 3). Live coverage on NASA television begins about two hours before landing and will continue all through Sunday and into Monday. You can access the NASA television page here. The main NASA TV link will probably overwhelmed, so I highly recommend you try out some of the alternative links. We’ll try and keep track of links to video streams in the forum which are able to handle the bandwidth.

Come on Spirit!

Fraser Cain
Publisher
Universe Today

Posted on by Fraser Cain

Life Found Under 1,350 Metres of Rock

Image credit: NASA

A team of scientists have discovered bacteria inside a hole that was drilled 1,350 metres into the volcanic rock near Hilo, Hawaii. The hole began in igneous rock on the Mauna Loa volcano, and then passed through lava from Mauna Kea. At 1,000 metres they encountered fractured basalt glass which formed when the lava flowed into the ocean. Upon close examination, they found that this lava had been changed by microorganisms. Using electron microscopy, they found tiny microbe spheres, and they were able to extract DNA. Scientists are finding life in more remote regions of the planet, and this gives hope that it might be on the other planets in our solar system as well.

A team of scientists has discovered bacteria in a hole drilled more than 4,000 feet deep in volcanic rock on the island of Hawaii near Hilo, in an environment they say could be analogous to conditions on Mars and other planets.

Bacteria are being discovered in some of Earth’s most inhospitable places, from miles below the ocean’s surface to deep within Arctic glaciers. The latest discovery is one of the deepest drill holes in which scientists have discovered living organisms encased within volcanic rock, said Martin R. Fisk, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University.

Results of the study were published in the December issue of Geochemistry, Geophysics and Geosystems, a journal published by the American Geophysical Union and the Geochemical Society.

“We identified the bacteria in a core sample taken at 1,350 meters,” said Fisk, who is lead author on the article. “We think there could be bacteria living at the bottom of the hole, some 3,000 meters below the surface. If microorganisms can live in these kinds of conditions on Earth, it is conceivable they could exist below the surface on Mars as well.”

The study was funded by NASA, the Jet Propulsion Laboratory, California Institute of Technology and Oregon State University, and included researchers from OSU, JPL, the Kinohi Institute in Pasadena, Calif., and the University of Southern California in Los Angeles.

The scientists found the bacteria in core samples retrieved during a study done through the Hawaii Scientific Drilling Program, a major scientific undertaking run by the Cal Tech, the University of California-Berkeley and the University of Hawaii, and funded by the National Science Foundation.

The 3,000-meter hole began in igneous rock from the Mauna Loa volcano, and eventually encountered lavas from Mauna Kea at 257 meters below the surface.

At one thousand meters, the scientists discovered most of the deposits were fractured basalt glass – or hyaloclastites – which are formed when lava flowed down the volcano and spilled into the ocean.

“When we looked at some of these hyaloclastite units, we could see they had been altered and the changes were consistent with rock that has been ‘eaten’ by microorganisms,” Fisk said.

Proving it was more difficult. Using ultraviolet fluorescence and resonance Raman spectroscopy, the scientists found the building blocks for proteins and DNA present within the basalt. They conducted chemical mapping exercises that showed phosphorus and carbon were enriched at the boundary zones between clay and basaltic glass – another sign of bacterial activity.

They then used electron microscopy that revealed tiny (two- to three-micrometer) spheres that looked like microbes in those same parts of the rock that contained the DNA and protein building blocks. There also was a significant difference in the levels of carbon, phosphorous, chloride and magnesium compared to unoccupied neighboring regions of basalt.

Finally, they removed DNA from a crushed sample of the rock and found that it had come from novel types of microorganisms. These unusual organisms are similar to ones collected from below the sea floor, from deep-sea hydrothermal vents, and from the deepest part of the ocean – the Mariana Trench.

“When you put all of those things together,” Fisk said, “it is a very strong indication of the presence of microorganisms. The evidence also points to microbes that were living deep in the Earth, and not just dead microbes that have found their way into the rocks.”

The study is important, researchers say, because it provides scientists with another theory about where life may be found on other planets. Microorganisms in subsurface environments on our own planet comprise a significant fraction of the Earth’s biomass, with estimates ranging from 5 percent to 50 percent, the researchers point out.

Bacteria also grow in some rather inhospitable places.

Five years ago, in a study published in Science, Fisk and OSU microbiologist Steve Giovannoni described evidence they uncovered of rock-eating microbes living nearly a mile beneath the ocean floor. The microbial fossils they found in miles of core samples came from the Pacific, Atlantic and Indian oceans. Fisk said he became curious about the possibility of life after looking at swirling tracks and trails etched into the basalt.

Basalt rocks have all of the elements for life including carbon, phosphorous and nitrogen, and need only water to complete the formula.

“Under these conditions, microbes could live beneath any rocky planet,” Fisk said. “It would be conceivable to find life inside of Mars, within a moon of Jupiter or Saturn, or even on a comet containing ice crystals that gets warmed up when the comet passes by the sun.”

Water is a key ingredient, so one key to finding life on other planets is determining how deep the ground is frozen. Dig down deep enough, the scientists say, and that’s where you may find life.

Such studies are not simple, said Michael Storrie-Lombardi, executive director of the Kinohi Institute. They require expertise in oceanography, astrobiology, geochemistry, microbiology, biochemistry and spectroscopy.

“The interplay between life and its surrounding environment is amazingly complex,” Storrie-Lombardi said, “and detecting the signatures of living systems in Dr. Fisk’s study demanded close cooperation among scientists in multiple disciplines – and resources from multiple institutions.

“That same cooperation and communication will be vital as we begin to search for signs of life below the surface of Mars, or on the satellites of Jupiter and Saturn.”

Original Source: OSU News Release

Posted on by Fraser Cain

Eighth Attempt to Reach Beagle 2 Fails

Image credit: Beagle 2

The search for Beagle 2 continues. Operators announced on December 31 that the British lander had failed to report in for the eighth time. At this point, the lander will have switched to a new mode where it tries to communicate twice a day. Although unlikely, it’s possible that Beagle 2’s onboard timer was reset during the landing, which would mean it was trying to communicate out of sync with Mars Odyssey and Earth-based radio telescopes. Mars Express will start searching on January 5, which operators believe will bring their best chances of finding it.

News on the outcome of today’s communication attempt via Mars Odyssey was delayed for several hours because NASA’s Deep Space Network is also being used for the Mars Exploration Rover and Stardust missions, which will be reaching their climax in the next few days.

As from last night, Beagle 2 should have switched to an emergency mode known as ‘ communication search mode 1′ (CSM 1). When the lander switches to CSM 1, it attempts to communicate twice every Martian day (sol), during the best daytime and best night-time pass by an available orbiter.

Meanwhile, ESA’s Mars Express orbiter was successfully inserted into a polar orbit around the Red Planet yesterday morning. This manoeuvre means that Mars Express will be ideally placed to communicate with Beagle 2 when it passes over the landing site in Isidis Planitia in a few days’ time.

An updated list of future opportunities to communicate with Beagle 2, including pre-programmed sessions with Mars Express, is posted on the Beagle 2 Web site.

The next Beagle 2 press briefing is scheduled to take place at the Media Centre in Camden on Sunday 4 January. Details will be confirmed on the Web sites at a later date.

Original Source: PPARC News Release

Posted on by Fraser Cain

Hubble Finds a Distant Proto-Cluster of Galaxies

Image credit: Hubble

An international team of astronomers have gathered evidence that galaxies formed very quickly after the Big Bang. The team found a proto-galaxy cluster more than 12 billion light-years away – the galaxies are so young that astronomers can see a flurry of stars forming inside them. This means they’re only 1.5 billion years old, a time when the Universe was only 10% of its current age. It’s believed that these clusters formed so quickly because these areas were incredibly dense with material.

Looking back in time nearly 9 billion years, an international team of astronomers found mature galaxies in a young universe. The galaxies are members of a cluster of galaxies that existed when the universe was only 5 billion years old, or about 35 percent of its present age. This compelling evidence that galaxies must have started forming just after the big bang was bolstered by observations made by the same team of astronomers when they peered even farther back in time. The team found embryonic galaxies a mere 1.5 billion years after the birth of the cosmos, or 10 percent of the universe’s present age. The “baby galaxies” reside in a still-developing cluster, the most distant proto-cluster ever found.

The Advanced Camera for Surveys (ACS) aboard NASA’s Hubble Space Telescope was used to make observations of the massive cluster, RDCS 1252.9-2927, and the proto-cluster, TN J1338-1942. Observations by NASA’s Chandra X-ray Observatory yielded the mass and heavy element content of RDCS 1252, the most massive known cluster for that epoch. These observations are part of a coordinated effort by the ACS science team to track the formation and evolution of clusters of galaxies over a broad range of cosmic time. The ACS was built especially for studies of such distant objects.

These findings further support observations and theories that galaxies formed relatively early in the history of the cosmos. The existence of such massive clusters in the early universe agrees with a cosmological model wherein clusters form from the merger of many sub-clusters in a universe dominated by cold dark matter. The precise nature of cold dark matter, however, is still not known.

The first Hubble study estimated that galaxies in RDCS 1252 formed the bulk of their stars more than 11 billion years ago (at redshifts greater than 3). The results were published in the Oct. 20, 2003 issue of the Astrophysical Journal. The paper’s lead author is John Blakeslee of the Johns Hopkins University in Baltimore, Md.

The second Hubble study uncovered, for the first time, a proto-cluster of “infant galaxies” that existed more than 12 billion years ago (at redshift 4.1). These galaxies are so young that astronomers can still see a flurry of stars forming within them. The galaxies are grouped around one large galaxy. These results will be published in the Jan. 1, 2004 issue of Nature. The paper’s lead author is George Miley of Leiden Observatory in the Netherlands.

“Until recently people didn’t think that clusters existed when the universe was only about 5 billion years old,” Blakeslee explained.

“Even if there were such clusters,” Miley added, “until recently astronomers thought it was almost impossible to find clusters that existed 8 billion years ago. In fact, no one really knew when clustering began. Now we can witness it.”

Both studies led the astronomers to conclude that these systems are the progenitors of the galaxy clusters seen today. “The cluster RDCS 1252 looks like a present-day cluster,” said Marc Postman of the Space Telescope Science Institute in Baltimore, Md., and co-author of both research papers. “In fact, if you were to put it next to a present-day cluster, you wouldn’t know which is which.”

A Tale of Two Clusters

How can galaxies grow so fast after the big bang? “It is a case of the rich getting richer,” Blakeslee said. “These clusters grew quickly because they are located in very dense regions, so there is enough material to build up the member galaxies very fast.”

This idea is strengthened by X-ray observations of the massive cluster RDCS 1252. Chandra and the European Space Agency’s XMM-Newton provided astronomers with the most accurate measurements to date of the properties of an enormous cloud of hot gas that pervades the massive cluster. This 160-million-degree Fahrenheit (70-million-degree Celsius) gas is a reservoir of most of the heavy elements in the cluster and an accurate tracer of its total mass. A paper by Piero Rosati of the European Southern Observatory (ESO) and colleagues that presents the X-ray observations of RDCS 1252 will be published in January 2004 in the Astronomical Journal.

“Chandra’s sharp vision resolved the shape of the hot gas halo and showed that RDCS 1252 is very mature for its age,” said Rosati, who discovered the cluster with the ROSAT X-ray telescope.

RDCS 1252 may contain many thousands of galaxies. Most of these galaxies, however, are too faint to detect. But the powerful “eyes” of the ACS pinpointed several hundred of them. Observations using ESO’s Very Large Telescope (VLT) provided a precise measurement of the distance to the cluster. The ACS enabled the researchers to accurately determine the shapes and colors of the 100 galaxies, providing information on the ages of the stars residing in them. The ACS team estimated that most of the stars in the cluster were already formed when the universe was about 2 billion years old. X-ray observations, furthermore, showed that 5 billion years after the big bang the surrounding hot gas had been enriched with heavy elements from these stars and had been swept away from the galaxies.

If most of the galaxies in RDCS 1252 have reached maturity and are settling into a quiet adulthood, the forming galaxies in the distant proto-cluster are in their energetic, unruly youth.

The proto-cluster TN J1338 contains a massive embryonic galaxy surrounded by smaller developing galaxies, which look like dots in the Hubble image.

The dominant galaxy is producing spectacular radio-emitting jets, fueled by a supermassive black hole deep within the galaxy’s nucleus. Interaction between these jets and the gas can stimulate a torrent of star birth.

The energetic radio galaxy’s discovery by radio telescopes prompted astronomers to hunt for the smaller galaxies that make up the bulk of the cluster.

“Massive clusters are the cities of the universe, and the radio galaxies within them are the smokestacks we can use for finding them when they are just beginning to form,” Miley said.

The two findings underscore the power of combining observations from many different telescopes that provided views of the distant universe in a range of wavelengths. Hubble’s advanced camera provided critical information on the structure of both distant galaxy clusters. Chandra’s and XMM-Newton’s X-ray vision furnished the essential measurements of the primordial gas in which the galaxies in RDCS 1252 are embedded, and accurate estimates of the total mass contained within that cluster. Large ground-based telescopes, like the VLT, provided precise measurements of the distance of both clusters as well as the chemical composition of the galaxies in them.

The ACS team is conducting further observations of distant clusters to solidify our understanding of how these young clusters and their galaxies evolve into the shape of things seen today. Their planned observations include using near-infrared observations to analyze the star-formation rates in some of the target clusters, including RDCS 1252, to measure the cosmic history of star formation in these massive structures. The team is also searching the regions around several ultra-distant radio galaxies for additional examples of proto-clusters. The team’s ultimate scientific goal is to establish a complete picture of cluster evolution beginning with the formation at the earliest epochs and detailing the evolution up to today.

Original Source: Hubble News Release

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