Cassini Finishes Saturnian Doubleheader

Pasadena CA (JPL) Apr 13, 2010 NASA's Cassini spacecraft completed its double flyby this week, swinging by Saturn's moons Titan and Dione with no maneuver in between. The spacecraft has beamed back stunning raw images of fractured terrain and craters big and small on Dione, a moon that had only been visited once before by Cassini.

The Titan flyby took place April 5, and the Dione flyby took place April 7 in the UTC time zone, and April 6 Pacific time. During the Titan flyby, an unexpected autonomous reset occurred and Cassini obtained fewer images of Titan than expected. But the cameras were reset before reaching Dione, which was the primary target on this double flyby.

Scientists are poring over data from Dione to discern whether the moon could be a source of charged particles to the environment around Saturn and material to one of its rings. They are also trying to understand the history of dark material found on Dione.

A fortuitous alignment of these moons allowed Cassini to attempt this doubleheader. Cassini had made three previous double flybys and another two are planned in the years ahead. The mission is nearing the end of its first extension, known as the Equinox Mission. It will begin its second mission extension, known as the Solstice Mission, in October 2010.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More information about the Titan flyby, dubbed "T67," is available here.

More information about the Dione flyby, dubbed "D2," is available here.

www.spacedaily.com

DARPA seeks to develop optics for space-based video surveillance system

ARLINGTON, Va.—Astronomers at the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., plan to develop a large, diffractive optics membrane and communications equipment for a geosynchronous orbit-based telescope, which is to be part of a space-based video surveillance system.

The program is called Membrane Optic Imager Real-time Exploitation (MOIRE), for which DARPA officials say they will issue a broad agency announcement (BAA) soon.

The MOIRE program seeks to provide persistent, real-time, tactical video to the warfighter. Developing diffractive membrane optics could help pave the way to low-cost geosynchronous imaging, DARPA scientists believe.

Ultimately, DARPA wants to develop a 20-meter system providing 24/7 visible National Imagery Interpretability Rating Scale (NIIRS) 3.5+ coverage over denied areas with at least a 1 Hz rate, a field of view larger than 60 square miles, with a cost less than $500 million each. Phase-3 of the MOIRE program will develop a 10-meter diffractive membrane.

The future MOIRE program BAA will seek industry proposals that address large, inexpensive, lightweight, deployable, diffractive membrane optics for geosynchronous orbit imaging systems; near-real-time image stabilization and tactical geolocation knowledge; a telescope design that increases spectral bandwidth; stability and dynamics of the large structure in geosynchronous orbit; and target motion detection capability for highway speeds.

More information is online at https://www.fbo.gov/spg/ODA/DARPA/CMO/DARPA-SN-10-31/listing.html.

mae.pennnet.com

Is densest Kuiper belt object a wayward asteroid?

A giant rock is walking among the "dirty iceballs" in the outer solar system, a new study suggests. Researchers say it may have journeyed there from the asteroid belt near Mars, or it may have been the victim of a cosmic crash that blasted away its once-icy exterior.

Quaoar was discovered in 2002 in the Kuiper belt, a ring of icy bodies beyond Neptune. At about 900 kilometres across, or 40 per cent as wide as Pluto, it is not the biggest denizen of the belt, but researchers now say it may be the densest.

Wesley Fraser and Michael Brown of Caltech confirmed its size by studying archival images from the Hubble Space Telescope. They also used Hubble images to study the motion of its moon, Weywot, which allowed them to calculate Quaoar's mass.

Combining the size and mass revealed Quaoar's density to be between 2.9 and 5.5 grams per cubic centimetre. That is much higher than that of other Kuiper belt residents like Pluto, which has a density of about 2.0 grams per cubic centimetre.

Quaoar's high density suggests it is made almost entirely of rock, unlike its neighbours, which are a mixture of ice and rock, the researchers conclude. They say the rocky world may be a refugee from the asteroid belt between Mars and Jupiter, thrown outwards early in the solar system's history, when the orbits of the giant planets are thought to have shifted.

Source:www.newscientist.com

CryoSat-2 polar mission launched

ESA PR 07-2010. Europe's first mission dedicated to studying the Earth’s ice was launched today from Kazakhstan. From its polar orbit, CryoSat-2 will send back data leading to new insights into how ice is responding to climate change and the role it plays in our 'Earth system'.

The CryoSat-2 satellite was launched at 15:57 CEST (13:57 UTC) on a Dnepr rocket provided by the International Space Company Kosmotras from the Baikonur Cosmodrome in Kazakhstan. The signal confirming that it had separated from the launcher came 17 minutes later from the Malindi ground station in Kenya.
CryoSat-2 replaces the original CryoSat satellite that was lost in 2005 owing to a launch failure. The mission objectives, however, remain the same: to measure changes in the thickness of the vast ice sheets that overlie Antarctica and Greenland, as well as variations in the thickness of the relatively thin ice floating in the polar oceans.

"We know from our radar satellites that sea ice extent is diminishing, but there is still an urgent need to understand how the volume of ice is changing," said Volker Liebig, ESA’s Director of Earth Observation Programmes. "To make these calculations, scientists also need information on ice thickness, which is exactly what our new CryoSat satellite will provide. We are now very much looking forward to receiving the first data from the mission."

The launch of CryoSat-2 marks a significant achievement for ESA's Earth observation programme and brings to three the number of its Earth Explorer satellites placed in orbit, all having been launched within a little over 12 months. CryoSat-2 follows on from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission, launched in March 2009, and the Soil Moisture and Ocean Salinity (SMOS) mission, launched last November.

Earth Explorers are launched in direct response to issues identified by the scientific community and aim to improve our understanding of how the Earth system works and the effect that human activity is having on natural processes.

Source: http://www.esa.int/esaCP/SEMH5ZZNK7G_index_0.html

Orion Nebula Fully Unveiled in New Telescope Image

Amateur and professional astronomers alike know the Orion Nebula as one of the most recognizable constellations in the night sky, and a new image from Europe's powerful VISTA telescope has captured it in a stunning new light. But rather than just seeing the visible cloud of gas enshrouding the stellar nursery, VISTA turned its infrared vision upon the young stars emerging in and around the nebula.
Four such youngsters at the center of the nebula have cleared out their immediate surroundings with ultraviolet radiation that causes nearby gas to glow. A red region directly above the center of the image reveals young stars that continue to form amidst clouds of interstellar gas. Such stars can eject gas at speeds of almost 435,000 miles per hour (700,000 km/hr).

Fainter red features below the Orion Nebula also represent lesser spots of activity where stars are being born.

Those features would typically be hidden from ordinary visible-light telescopes. But don't let that stop you from pointing your own camera toward the night sky -- as PopSci's Eric Adams noted in his DIY astrophotography guide, it's all worth the trouble.

Source: www.popsci.com

'Ingredients for Life' Present on Saturn's Moon Enceladus, Say Scientists

Some of 'the major ingredients for life' are present on one of Saturn's moons, according to University College London scientists.

A team from the Mullard Space Science Laboratory working on the Cassini-Huygens mission have found negatively charged water ions in the ice plume of Enceladus.

Their analysis of data gathered during the spacecraft's plume fly-throughs in 2008 provide evidence for the presence of liquid water.

The spacecraft's plasma spectrometer, used to gather this data, also found other species of negatively charged ions including hydrocarbons.

MSSL's Professor Andrew Coates, lead author of a paper on the latest discovery, said: "While it's no surprise that there is water there, these short-lived ions are extra evidence for sub-surface water and where there's water, carbon and energy, some of the major ingredients for life are present.

The surprise for us was to look at the mass of these ions. There were several peaks in the spectrum, and when we analysed them we saw the effect of water molecules clustering together one after the other."

Enceladus thus joins Earth, Titan and comets where negatively charged ions are known to exist in the solar system. Negative oxygen ions were discovered in Earth's ionosphere at the dawn of the space age. At Earth's surface, negative water ions are present where liquid water is in motion, such as waterfalls or crashing ocean waves.

The plasma spectrometer measures the density, flow velocity and temperature of ions and electrons that enter the instrument. But since the discovery of Enceladus' water ice plume, the instrument has also successfully captured and analysed samples of material in the jets.

Early in its mission, Cassini-Huygens discovered the plume that fountains water vapour and ice particles above Enceladus. Since then, scientists have found that these water products dominate Saturn's magnetic environment and create Saturn's huge E-ring.

At Titan, the same instrument detected extremely large negative hydrocarbon ions with masses up to 13,800 times that of hydrogen. Dr Coates and his colleagues believe large ions are the source of the smog-like haze that blocks most of Titan's surface from view.

The new findings add to astronomers' growing knowledge of the detailed chemistry of Enceladus' plume and Titan's atmosphere, giving new understanding of environments beyond Earth where prebiotic or life-sustaining environments might exist.

Professor Keith Mason, Chief Executive of the Science and Technology Facilities Council (STFC), which funds the UK involvement in Cassini-Huygens, said: "This measurement of water ions in the ice plume of Enceladus is incredibly exciting and provides us with further hope of finding water and maybe even life on this distant icy moon."

The Cassini-Huygens mission is a co-operative project of NASA, the European Space Agency and the Italian Space Agency.

Source: www.sciencedaily.com

Endeavour Lifts Off in Space Shuttle's Final Night Launch

It's a sight captured by many a late-night stargazer: a shuttle streaking through the dark sky on its way to orbit. Last night, a gorgeous predawn launch of the space shuttle Endeavour marked the last scheduled night launch ever for the retiring NASA vehicle, even as NASA looks forward to a new age of commercial spaceflight.All four of the remaining shuttle flights are slated for the daytime, Space.com reports.

The 13-day mission's highlight involves bringing a huge new window to the International Space Station, so that residents of the orbital outpost can better direct the robotic arm and maybe even snap some prettier Twitpics . The window's addition in the new node would bring the space station to about 90 percent completion.
It's just one bittersweet part of the long goodbye for the shuttle. The vehicle's retirement will not only have riple effects on NASA employees and Florida's economy, but also marks the beginning of a transition toward relying more upon private vehicles to launch cargo and crew into low Earth orbit. The Ob

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ama administration's recent budget for NASA killed plans for the Ares rockets to replace the space shuttle, and instead refocused the U.S. space agency on more deep space exploration.

Readers curious about how the new space age might look can consult PopSci's January issue that covers the impending commercial space rush.

Source: www.popsci.gr