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

Posted on by Fraser Cain

The Search for Beagle 2 Continues

Image credit: ESA

Controllers have made two more attempts to reach the Beagle 2 lander, which was thought to have entered Mars’ atmosphere on December 25: once with both the Jodrell Bank radio telescope and again with Mars Odyssey. Although they’re disappointed, the engineers still have a few tricks up their sleeves. A special team has been put together, and is working around the clock to devise solutions for potential problems with the lander; if there are hardware or software problems, or if it’s ended up at an unusual angle. People will really start to lose hope in early January when Mars Express reaches its final polar orbit – it’s the spacecraft Beagle 2 was designed to communicate with.

Two attempts to communicate with Beagle 2 during the last 24 hours – first with the 76 metre (250 feet) Lovell Telescope at Jodrell Bank Observatory in Cheshire, UK, and then this morning with the Mars Odyssey orbiter – ended without receiving a signal. Despite this outcome, fresh attempts to scan for a signal from Beagle 2 will be made over the coming days.

Meanwhile, scientists and engineers are eagerly awaiting ESA’s Mars Express spacecraft return close enough to Mars to try to establish contact with Beagle 2. This may be possible from 4 January 2004.

Mars Express was always intended to be the prime communication relay for Beagle 2, and the lander team is hopeful that a link can be established at that time if it has not already been achieved with Mars Odyssey.

“We need to get Beagle 2 into a period when it can broadcast for a much longer period,” says Professor Colin Pillinger, Beagle 2 lead scientist. “This will happen around the 4 January after the spacecraft has experienced a sufficient number of communication failures to switch to automatic transmission mode.”

Both Professor Pillinger and Professor David Southwood, ESA Director of Science, agreed that the best chance to establish communication with Beagle 2 would now seem to be through Mars Express.

At present, Mars Express is far from the planet and preparing to fire its engines for a major trajectory change that will move it into a polar orbit around Mars.

“We will have no satisfaction until we have a full mission” said Professor Southwood. “Today I’m certainly frustrated, but I’m still confident: let’s wait now until the mothership will have the possibility to get in contact with her baby. With Mars Express we will be using a system that we have fully tested and understand.”

Original Source: ESA News Release

Posted on by Fraser Cain

Jodrell Listens to Mars, But No Beagle 2

Image credit: PPARC

After NASA’s Mars Odyssey failed to make contact with the British-built Beagle 2 lander on Christmas morning, all hopes were pinned on the Earth-based Jodrell Bank radio telescope to hear its faint signal. After listening for more than two hours, unfortunately, operators failed to tune into the spacecraft’s signal. Then another opportunity to communicate with Odyssey on December 26 failed as well. Mission controllers haven’t completely lost hope, though. When Mars Express reaches its final orbit in early January, it will be the best opportunity to communicate with Beagle 2 and help determine, once and for all, if the spacecraft survived its landing.

Scientists were hopeful that the 250 ft (76 m) Lovell Telescope, recently fitted with a highly sensitive receiver, would be able to pick up the outgoing call from the Mars lander between 19.00 GMT and midnight last night. An attempt to listen out for Beagle’s call home by the Westerbork telescope array in the Netherlands was unfortunately interrupted by strong radio interference.

The next window of opportunity to communicate via Mars Odyssey will open at 17.53 GMT and close at 18.33 GMT this evening, when the orbiter is within range of the targeted landing site on Isidis Planitia.

Another communication session from Jodrell Bank is scheduled between 18.15 GMT and midnight tonight, when Mars will be visible to the radio telescope. It is also hoped that the Stanford University radio telescope in California will be able to listen for the carrier signal on 27 December.

The Beagle 2 team plans to continue using the Mars Odyssey spacecraft as a Beagle 2 communications relay for the next 10 days, after which the European Space Agency’s Mars Express orbiter will become available.

Mars Express, which was always planned to be Beagle 2’s main communication link with Earth, successfully entered orbit around the planet on 25 December and is currently being manoeuvred into its operational polar orbit.

Meanwhile, 13 more attempts to contact Mars Odyssey have been programmed into Beagle 2’s computer. If there is still no contact established after that period, Beagle 2 is programmed to move into auto-transmission mode, when it will send a continuous on-off pulse signal throughout the Martian daylight hours.

The first window of opportunity to communicate with Beagle 2 took place at around 06.00 GMT yesterday, when NASA’s Mars Odyssey spacecraft flew over the planned landing site. In the absence of a signal from the 33 kg lander, the mission team contacted Jodrell Bank to put their contingency plan into operation.

At present, Beagle 2 should be sending a pulsing on-off signal once a minute (10 seconds on, 50 seconds off). Some 9 minutes later, this very slow “Morse Code” broadcast should reach Earth after a journey of some 98 million miles (157 million km).

Although the Beagle’s transmitter power is only 5 watts, little more than that of a mobile phone, scientists are confident that the signal can be detected by the state-of-the-art receiver recently installed on the Lovell Telescope. However, a significant drop in signal strength would require rigorous analysis of the data before it could be unambiguously identified.

Although the ground-based radio telescopes will not be able to send any reply, the new information provided by detection of the transmission from Beagle 2 would enable the mission team to determine a provisional location for Beagle 2. This, in turn, would allow the communications antenna on Mars Odyssey to be directed more accurately towards Beagle 2 during the orbiter’s subsequent overhead passes.

Original Source: PPARC News Release

Posted on by Fraser Cain

Mars Express Arrives But No Word From Beagle 2

Image credit: Beagle 2

The European Space Agency confirmed that Mars Express has arrived safely at the Red Planet, ending its 400 million kilometre journey, and beginning its mission to map the surface and search for underground water. The spacecraft began its 37 minute orbital insertion burn at 0247 UTC. Controllers believe that the British-built Beagle 2 also reached Mars at approximately the same time, but the lander failed to make contact with Mars Odyssey, which should have relayed communications back to Earth. Controllers will attempt to make contact again on December 25 at 2200 UTC, this time with the Earth-based Jodrell Bank telescope in Cheshire, UK.

This morning, after a journey lasting 205 days and covering 400 million kilometres, the European Mars Express space probe fired its main engine at 03:47 CET for a 37-minute burn in order to enter an orbit around Mars. This firing gave the probe a boost so that it could match the higher speed of the planet on its orbit around the Sun and be captured by its gravity field, like climbing in a spinning merry-go-round. This orbit insertion manoeuvre was a complete success.

This is a great achievement for Europe on its first attempt to send a space probe into orbit around another planet.

At approximately the same time, the Beagle 2 lander, protected by a thermal shield, entered the Martian atmosphere at high velocity and is expected to have reached the surface at about 03:52 CET. However, the first attempt to communicate with Beagle 2, three hours after landing, via NASA?s Mars Odyssey orbiter, did not establish radio contact. The next contact opportunity will be tonight at 23:40 CET.

The tiny lander was released from the orbiter six days ago on a collision course towards the planet. Before separation, its on-board computer was programmed to operate the lander on its arrival at the surface, by late afternoon (Martian time). According to the schedule, the solar panels must deploy to recharge the on-board batteries before sunset. The same sequence also tells Beagle 2 to emit a signal at a specific frequency for which the Jodrell Bank Telescope, UK, will be listening later tonight. Further radio contacts are scheduled in the days to come.

In the course of the coming week, the orbit of Mars Express will be gradually adjusted in order to prepare for its scientific mission. Mars Express is currently several thousand kilometres away from Mars, in a very elongated equatorial orbit. On 30 December, ESA’s ground control team will send commands to fire the spacecraft’s engines and place it in a polar, less-elongated orbit (about 300 kilometres pericentre, 10000 apocentre, 86? inclination). From there, ESA’s spacecraft will perform detailed studies of the planet’s surface, subsurface structures and atmosphere. Commissioning of some of the on-board scientific instruments will begin towards mid-January and the first scientific data are expected later in the month.

?The arrival of Mars Express is a great success for Europe and for the international science community. Now, we are just waiting for a signal from Beagle 2 to make this Christmas the best we could hope for!? said David Southwood, head of ESA?s Science Directorate. ?With Mars Express, we have a very powerful observatory in orbit around Mars and we look forward to receiving its first results. Its instruments will be able to probe the planet from its upper atmosphere down to a few kilometres below the surface, where we hope to find critical clues concerning the conditions for life, in particular traces of water. We expect this mission to give us a better understanding of our neighbour planet, of its past and its present, answering many questions for the science community and probably raising an even greater number of fascinating new ones. I hope we can see it as opening up a new era of European exploration?.

Original Source: ESA News Release

Posted on by Fraser Cain

Robert Zubrin Responds to Your Questions

A few weeks ago I reviewed Dr. Robert Zubrin’s newest book, Mars on Earth. I’ve had feedback from Universe Today readers in the past that they they’d like to ask Zubrin a few questions about his goal of sending humans to Mars, so I figured this would be a good chance to get those questions answered. I gave people on the forum a few days to propose their questions and then I selected four questions that I felt were original, and didn’t really cover territory that we’ve heard Zubrin talk about in past (such as in The Case for Mars and Entering Space).

Thanks to everyone who participated, and thanks to Dr. Zubrin for taking the time to respond. If you had fun with this, let me know if there’s anyone else you’d like to throw questions at, and maybe I can track them down.

If you’re interested in the goal of sending humans to Mars, I highly recommend you take a look at the Mars Society, which Robert Zubrin is the President. Click here to visit their website.

1. Dave Mitsky: What do you feel is the most dangerous aspect of the Mars Direct plan?

Zubrin: The ascent from Mars in the Earth Return Vehicle (ERV). The liftoff from Mars followed by trans-Earth injection only requires about half the delta-V as the outbound trip, but there will be much fewer people there to monitor it. So we need really good automated health maintenance and monitoring equipment on the ERV, allowing the launch to be effectively controlled from Earth.

2. Eli: What do you think should be done to make sure a manned Mars mission will not be a “take a photo and not come back for 3 decades” mission ala Apollo?

Zubrin: The problem with Apollo was twofold; that it was the creature of the political class, and the basis upon which it was sold to much of the political class. When it achieved its stated Cold War objective, the elites were then free to dismantle it, as there was no organic space movement with a deeper goal around to sustain it.

We need to make sure that the Mars program is created with the stated goal of opening a new world for humanity, and we need to organize a grassroots movement that supports it and sustains it on that basis.

Black abolitionist leader Frederick Douglas once said “Emancipation would lose half its value were it won by the efforts of white men alone.” He was right. We need to make sure that the Mars program is OUR program, and not THEIR program.

3. Josh: What feedback have the people in power – the government or NASA – given to your ideas?

Zubrin: Many people at the NASA field centers have become supporters of Mars Direct. Some of the headquarters crowd still opposes it as they oppose any destination driven orientation that would force NASA to abandon its constituency-driven method of spending and provide a metric against which results could be measured.

4. exAstro: If it comes down to a cost/benefit analysis we’ll probably never go to Mars- at least by current thinking. So- how do we move beyond that mindset? What would prompt the ultimate decision makers (purse holders) to decide that it’s in “our” best interest to go to Mars? I assume that the technology is not at issue.

Zubrin: I dispute the premise of the question. A cost-benefit analysis demands that we abandon the wasteful Shuttle-era approach of constituency driven spending and return to the highly productive destination driven Apollo era approach.

NASA spending is now 90% of the average Apollo era (1961-1973) level. We spent as much on NASA, in real inflation-adjusted dollars, between 1990 and 2003 as we did between 1961 and 1973. But compare the results. Between 1961-1973 we went from near zero space capability to fly Mercury, Gemini, Apollo, Skylab, Ranger, Mariner, Surveyor, Pioneer Jupiter; we developed hydrogen/oxygen rocket engines, multi-staged heavy lift launch vehicles, in space life support systems, spacesuits, soft landing techniques, lunar rovers, RTGs, space nuclear reactors, nuclear rocket engines, reentry techniques, interplanetary navigation and communication technologies; we built the Deep Space Network, Johnson Space Center, JPL (in the sense it exists today), the Cape Canaveral launch complex, and we inspired a generation of youth to enter science and engineering.

In contrast, between 1990 and 2003 we flew about three-score STS missions, launched and repaired Hubble, launched half a dozen lunar or planetary probes (compared with over 40 for 61-73), and launched a space station which is still less capable than Skylab. So the mission productivity was much less, but the technology return was even worse; as a result of the lack of any forcing function, NASA, despite its claim to be focussing on technology development, developed NO significant new space technologies during the 1990-2003 period, built no new infrastructure, and failed to inspire youth in any way remotely comparable to that it achieved in the sixties.

So if the question is; how do we assure the taxpayers of a real return on their space dollar, there is only one answer; Give NASA a job that is worthy of a $16 billion/year space agency. Assign it the task of sending humans to Mars within a decade.

Posted on by Fraser Cain

One Day to Go for Beagle 2

This time of year, I usually wind things down at Universe Today since the various news sources are all on holiday and there isn’t much to report. This year; however, it’s an entirely different story. The British-built Beagle 2 lander will be touching down on Mars on December 25. Stardust reaches Comet Wild 2 on January 2, and the Mars Exploration Rover arrives on January 3. Things couldn’t be busier.

So, first up… Beagle 2 and Mars Express. The lander is expected to arrive at 0254 UTC on December 25 (9:54 pm EST December 24). We won’t know if Beagle 2 arrived safely for another four hours or so, when Mars Express enters orbit – data won’t arrive back on Earth until 0700 UTC (2:00am EST). Keep your fingers crossed.

The European Space Agency has said they’ll be broadcasting information about the landing live on television, but I haven’t been able to find a link on the web for it (if you know of one, let me know). You can visit their special coverage of the landing and Mars Express arrival here. Or go straight to the Beagle 2 website, where they’ll just be focused on the lander. As I find cool stuff on the web, I’ll let you know.

And make sure you come visit the Universe Today forum and share your thoughts and ideas about the missions with the rest of our community.

Have a happy and safe holiday. See you on Mars!

Fraser Cain
Publisher
Universe Today

Posted on by Fraser Cain

JIMO Ion Engine Passes the Test

Image credit: NASA/JPL

A new ion engine design, under consideration for NASA’s Jupiter Icy Moons Orbiter mission, has been successfully tested. This was the first performance test of the Nuclear Electric Xenon Ion System, which will use a nuclear reactor to generate electricity for the spacecraft’s ion engine – previous ion engines, like on Deep Space 1 and SMART-1 are solar powered. The new engine operated with 10 times the thrust of Deep Space 1, and should be able to run for 10 years; enough time to visit each of Jupiter’s icy moons which are potential candidates for life.

A new ion propulsion engine design, one of several candidate propulsion technologies under study by NASA’s Project Prometheus for possible use on the proposed Jupiter Icy Moons Orbiter mission, has been successfully tested by a team of engineers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

The event marked the first performance test of the Nuclear Electric Xenon Ion System (Nexis) ion engine at the high-efficiency, high-power, and high-thrust operating conditions needed for use in nuclear electric propulsion applications. For this test the Nexis engine was powered using commercial utility electrical power. Ion engines used on the proposed Jupiter Icy Moons Orbiter spacecraft would draw their power from an on-board space nuclear reactor. The ion engines, or electric thrusters, would propel the orbiter around each of the icy worlds orbiting Jupiter — Ganymede, Callisto and Europa — to conduct extensive, close-range exploration of their makeup, history and potential for sustaining life.

“On the very first day of performance testing, the Nexis thruster demonstrated one of the highest efficiencies of any xenon ion thruster ever tested,” said Dr. James Polk, the principal investigator of the ion engine under development at JPL.

The test was conducted on December 12, in the same vacuum chamber at JPL where earlier this year, the Deep Space 1 flight spare ion thruster set the all time endurance record of 30,352 hours (nearly 3.5 years) of continuous operation. The Nexis engine operated at a power level of over 20 kilowatts, nearly 10 times that of the Deep Space 1 thruster, which enables greater thrust and ultimately higher spacecraft velocities for a given spacecraft mass. It is designed to process two metric tons of propellant, 10 times the capability of the Deep Space 1 engine, and operate for 10 years, two to three times the Deep Space 1 thruster life.

Team members working on the Nexis engine also helped develop the first ion engine ever flown on NASA’s highly successful Deep Space 1 mission, which validated 12 high-risk advanced technologies, among them the use of the first ion engine in space.

“The Nexis thruster is a larger, high performance descendant of the Deep Space 1 thruster that achieves its extraordinary life by replacing the metal, previously used in key components, with advanced carbon based materials,” said Tom Randolph, the Nexis program manager at JPL. “The thruster’s revolutionary performance results from an extensive design process including simulations using detailed computer models developed and validated with the Deep Space 1 life test, and other component test data.”

Unlike the short, high-thrust burns of most chemical rocket engines that use solid or liquid fuels, the ion engine emits only a faint blue glow of electrically charged atoms of xenon – the same gas found in photo flash tubes and in many lighthouse bulbs. The thrust from the engine is as gentle as the force exerted by a sheet of paper held in the palm of your hand. Over the long haul though, the engine can deliver 20 times as much thrust per kilogram of fuel than traditional rockets.

Key to the ion technology is its high exhaust velocity. The ion engine can run on a few hundred grams of propellant per day, making it lightweight. Less weight means less cost to launch, yet an ion-propelled spacecraft can go much faster and farther than any other spacecraft.

“This test, in combination with the recent test of the High Power Electric Propulsion ion engine at NASA’s Glenn Research Center, is another example of the progress we are making in developing the technologies needed to support flagship space exploration missions throughout the solar system and beyond,” said Alan Newhouse, director, Project Prometheus. “We have challenged our team with difficult performance goals and they are demonstrating their ability to be creative in overcoming technical challenges.”

NASA’s Project Prometheus is making strategic investments in space nuclear fission power and electric propulsion technologies that would enable a new class of missions to the outer Solar System, with capabilities far beyond those possible with current power and propulsion systems. The first such mission under study, the Jupiter Icy Moon Orbiter would launch in the next decade and provide NASA significantly improved scientific and telecommunications capabilities and mission design options. Instead of generating only hundreds of watts of electricity like the Cassini or Galileo missions, which used radioisotope thermoelectric generators, the Jupiter Icy Moons Orbiter could have up to tens of thousands of watts of power, increasing the potential science return many times over.

Development of the Nexis ion engine is being carried out by a team of engineers from JPL; Aerojet, Redmond, Wash.; Boeing Electron Dynamic Devices, Torrance, Calif.; NASA’s Marshall Space Flight Center, Huntsville, Ala.; Colorado State University, Fort Collins, Colo.; Georgia Institute of Technology, Atlanta, Ga.; and the Aerospace Corporation, Los Angeles, Calif.

For more information about Project Prometheus on the Internet, visit: http://spacescience.nasa.gov/missions/prometheus.htm .

Information on the proposed Jupiter Icy Moons Orbiter mission is available at: NASA Jimo MIssion .

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Dark Matter Bends Light from a Distant Quasar

Image credit: SDSS

Gravitational lensing happens when the light from a distant object, such as a quasar, is distorted by the gravity of a closer object. Astronomers have discovered just such a lens, where the distortions are so great, they have to be caused by a significant amount of dark matter – the visible material alone couldn’t be responsible. Dark matter is predicted by its gravitational influence on galaxies and stars in the Universe, but so far, astronomers aren’t really sure what it is; whether it’s just regular matter which is too cold to be seen from Earth, or some kind of exotic particle.

Sloan Digital Sky Survey scientists have discovered a gravitationally lensed quasar with the largest separation ever recorded, and, contrary to expectations, found that four of the most distant, most luminous quasars known are not gravitationally lensed.

Albert Einstein’s Theory of General Relativity predicts that the gravitational pull of a massive body can act as a lens, bending and distorting the light of a distant object. A massive structure somewhere between a distant quasar and Earth can “lens” the light of a quasar, making the image substantially brighter and producing several images of one object.

In a paper published in the December 18/25 edition of NATURE magazine, a Sloan Digital Sky Survey (SDSS) team led by University of Tokyo graduate students Naohisa Inada and Masamune Oguri report that four quasars in close proximity are, in fact, the light from one quasar split into four images by gravitational lensing.

More than 80 gravitationally lensed quasars have been discovered since the first example was found in 1979. A dozen of the cataloged lensed quasars are SDSS discoveries, of which half are the result of the work of Inada and his team.

But what makes this latest finding so dramatic is that the separation between the four images is twice as large as that of any previously known gravitationally lensed quasar. Until the discovery of this quadruple lens quasar, the largest separation known in a gravitationally lensed quasar was 7 arcseconds. The quasar found by the SDSS team lies in the constellation Leo Minor; it consists of four images separated by 14.62 arcseconds.

In order to produce such a large separation, the concentration of matter giving rise to the lensing has to be particularly high. There is a cluster of galaxies in the foreground of this gravitational lens; the dark matter associated with the cluster must be responsible for the unprecedented large separation.

“Additional observations obtained at the Subaru 8.2 meter telescope and Keck telescope confirmed that this system is indeed a gravitational lens,” explains Inada. “Quasars split this much by gravitational lensing are predicted to be very rare, and thus can only be discovered in very large surveys like the SDSS.”

Oguri added: “Discovering one such wide gravitational lens out of over 30,000 SDSS quasars surveyed to date is perfectly consistent with theoretical expectations of models in which the universe is dominated by cold dark matter. This offers additional strong evidence for such models.” (Cold dark matter, unlike hot dark matter, forms tight clumps, the kind that causes this kind of gravitational lens.)

“The gravitational lens we have discovered will provide an ideal laboratory to explore the relation between visible objects and invisible dark matter in the universe,” Oguri explained.

In a second paper to be published in the Astronomical Journal in March 2004, a team led by Gordon Richards of Princeton University used the high resolution of the Hubble Space Telescope to examine four of the most distant known quasars discovered by SDSS for signs of gravitational lensing.

Looking to great distances in astronomy is looking back in time. These quasars are seen at a time when the universe was less than 10percent of its present age. These quasars are tremendously luminous, and are thought to be powered by enormous black holes with masses several billion times that of the Sun. The researchers said it is a real mystery how such massive black holes could have formed so early in the universe. Yet if these objects are gravitationally lensed, SDSS researchers would infer substantially smaller luminosities and therefore black hole masses, making it easier to explain their formation.

“The more distant a quasar, the more likely a galaxy lies between it and the viewer. This is why we expected the most distant quasars to be lensed,” explained SDSS researcher Xiaohui Fan of the University of Arizona. However, contrary to expectations, none of the four shows any sign of multiple images that is the hallmark of lensing.

“Only a small fraction of quasars are gravitationally lensed. However, quasars this bright are very rare in the distant universe. Since lensing causes quasars to appear brighter and therefore easier to detect, we expected that our distant quasars were the ones most likely to be lensed,” suggested team member Zoltan Haiman of Columbia University.

“The fact that these quasars are not lensed says that astronomers have to take seriously the idea that quasars a few billion times the mass of the Sun formed less than a billion years after the Big Bang”, said Richards. “We’re now looking for more examples of high-redshift quasars in the SDSS to give theorists even more supermassive black holes to explain.”

Original Source: SDSS News Release