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Tuesday, 4 March 2008

Feature: JPL Helps Shoot for the Moon, Stars, Planets and More

Feature                                                      Mar. 3, 2008

JPL Helps Shoot for the Moon, Stars, Planets and More

The Big Picture

A giant telescope, galaxy maps, and laser beacons on Mars are only a few of the ideas
that teams selected by NASA will study for the next generation of astronomy and
astrophysics missions. NASA's Jet Propulsion Laboratory, Pasadena, Calif., will help
usher in this new era by playing an active role in 15 of the 19 science teams chosen to
look at new concepts for future missions.

The 15 teams will explore concepts for missions to hunt for planets orbiting other stars
(exoplanets) and to answer various astrophysics questions. JPL will manage six exoplanet
and five astrophysics mission concepts and contribute to another four astrophysics
mission plans managed from other NASA centers by aiding engineering and mission
design, refining the science goals and supporting cost estimates.

The final reports will be put up for review in front of the Decadal Survey Committee,
which sets the priorities for astronomy and astrophysics studies every 10 years, said
Michael Werner, the chief scientist for astronomy and physics at JPL.

"We're delighted at JPL's involvement," said Werner, who is also the project scientist of
NASA's Spitzer Space Telescope. "We're looking forward to working with our
government, industrial and academic partners to develop really exciting mission
concepts."

Planets, Planets Everywhere

With half a dozen exoplanet mission concepts in the mix, it's clear the hunt for smaller,
Earthlike planets that might harbor life is very much on the minds of NASA and the
public.

"The idea has been discussed by thinkers going back to the ancient Greeks, Renaissance
thinkers, and all the way up to modern times," said Michael Devirian, manager of the
Exoplanet Exploration Program at JPL, which encompasses NASA's planet-finding
efforts.  "One can imagine primitive man sitting around the campfire, wondering what's
outside the circle of light, just as we now conduct our search, outside the circle of light of
our sun.  The search for other planets touches all of us deep in our psyche, and it's very
easy to relate to and imagine what could be out there."

Planet mania is catching the fancy of the younger generation, according to Jakob Van
Zyl, who heads JPL's Astronomy and Physics Directorate. "Anytime there's an exoplanet
session at a science conference, you have a lot of young people showing up and
interested."

Devirian said NASA plans to issue an announcement of opportunity in 2009 for a
moderate-scale exoplanet mission.

"The concepts that we are working on are candidates for this mission," Devirian said.
"NASA will wait and see what the Decadal Survey Committee has to say before selecting
a mission."

The various exoplanet mission concepts span all the techniques currently being
developed to detect planets, according to Devirian. Several will attempt to zoom in and
image giant planets that orbit around some of our neighboring stars. These studies will
use different types of coronagraphs, mask-like instruments that attach to telescopes to
block the harsh, blinding starlight that hides the dimmer planets. By using coronagraphs,
scientists can find the comparatively miniscule light from planets orbiting close to these
stars. One of these proposed missions combines a coronagraph on the telescope with an
external occulter, a starlight blocker flying separately thousands of kilometers away, in
order to look very close to a star for planets in orbits similar to the orbit of Earth around
our star, the sun.

The remaining two exoplanet mission concepts use interferometers. Interferometers
utilize multiple telescopes to simulate an enormous telescope with great resolving power.

One of the mission concepts will test a nulling interferometer to cancel a star's light with
the goal of imaging giant planets, and, by seeing light from the ring of dust that marks a
planet's orbit, learn about the architectures of planetary systems. The other mission
concept will study a large stellar interferometer--6 meters, or 20 feet long--that could be
used to find planets by measuring the star's "wiggle," or its reciprocal motion with the
planets around it.

"The science of exoplanets is one of the most vibrant and exciting areas to study at this
time," Devirian said. "It is also one of the most challenging, so it's very important to
conduct these studies to come up with the best approaches for these missions."

Meanwhile, Elsewhere in the Universe.......

Van Zyl notes that astrophysics includes other research areas that are also grabbing their
share of attention.  "Astrophysics is a broad field of study, and that fact is manifested in
the wide range of topics these teams are investigating."

The nine astrophysics mission concept studies will range from testing general relativity to
mapping the early universe's rapid expansion. JPL will manage five of these studies. One
of these will perform a systematic study of all astrophysical processes relevant to the
births and deaths of stars in both our galaxy and in nearby galaxies. Another will study
the polarization of the cosmic microwave background, the radiation left over when our
universe was formed. A third will measure the shape of the cosmic inflation potential by
conducting a near-infrared large-area redshift survey capable of detecting galaxies that
formed early in the history of the universe.

Another astrophysics study will explore placing laser beacons on Mars and measuring the
precise distance to perform the most precise test ever of Einstein's theory of general
relativity. Last but not least, two moon-related studies include a "Dark Ages" lunar
interferometer to map out hydrogen gas clouds formed during the early days of the
universe.

JPL will also contribute to astrophysics mission concept studies managed by other NASA
centers, including a study of a giant telescope (eight to 16 meters in diameter, or 26 to 52
feet), and an investigation of the organic molecules floating in the spaces between stars, a
means of looking at the origin of cosmic rays.

Werner said he was pleased that NASA was able to sponsor these studies as a way to
prepare for the Decadal Survey Committee.  "The success of these missions will reflect
the strength of JPL's astrophysics activities," Werner said.

The Who's Who of New Missions!

The 15 selected science teams and their mission concept studies are:

Exoplanet Missions:

*       Access (Actively-Corrected Coronagraphs for Exoplanet System Studies):
comparing coronagraphs for exoplanet missions (JPL both manages the mission
concept study and is home institution for the principal investigator, John Trauger)
*       Davinci (Dilute Aperture Visible Nulling Coronagraph Imager): examining a
nulling interferometer (JPL both manages the mission concept study and is home
institution for the principal investigator, Michael Shao)
*       PECO (Pupil-mapping Exoplanet Coronagraphic Observer): refining a Phase
Induced Amplitude Apodization Coronograph (with principal investigator Olivier
Guyon of the University of Arizona)
*        Epic (Extrasolar Planetary Imaging Coronagraph): directly imaging exoplanets
orbiting nearby stars (with principal investigator Mark Clampin of NASA's
Goddard Space Flight Center)
*       XPC (eXtrasolar Planet Characterizer): examining external and internal
interferometers (with principal investigator David Spergel of Princeton
University)
*       Planet Hunter: examining a six-meter stellar (26-foot) interferometer (with
principal investigator Geoff Marcy of the University of California, Berkeley)

Astrophysics Missions

*       SFO (Star Formation Observatory): studying star formation (with principal
investigator Paul Scowen of Arizona State University)
*       MLR (Mars Laser Ranging): testing general relativity using ranging to Mars (with
principal investigator Tom Murphy of the University of California, San Diego)
*       LARC (Lunar Array for Radio Cosmology): building a lunar array for radio
cosmology (with principal investigator Jacqueline Hewitt of the Massachusetts
Institute of Technology)
*       CIP (Cosmic Inflation Probe): high redshift galaxy survey (with principal
investigator Gary Melnick of the Smithsonian Astrophysical Observatory)
*       Epic (Experimental Probe of Inflationary Cosmology): studying the polarization
of radiation from the cosmic microwave background (with principal investigator
Stephen Meyer of the University of Chicago)
*       Atlast (Advanced Technology Large Aperture Space Telescopes): designing an
eight to 16 meter (26 to 52 feet) optical space telescope (with principal
investigator Marc Postman of the Space Telescope Science Institute)
*       Dali (Dark Ages Lunar Interferometer): detection of low-frequency radio
emissions (with principal investigator Joe Lazio of the Naval Research
Laboratory)
*       Aspire (Astrobiology Space Infrared Explorer): searching for organic molecules
in interstellar space (with principal investigator Scott Sandford of NASA's Ames
Research Center)
*       Oasis (Orbiting Astrophysical Spectrometer In Space): determining the origin of
cosmic rays (with principal investigator James Adams of NASA's Marshall Space
Flight Center)


Media Contacts: Diya Chacko
818-354-9382/818-393-5464
dschacko@jpl.nasa.gov

Jane Platt 818-354-0880
Jet Propulsion Laboratory, Pasadena, Calif.
Jane.platt@jpl.nasa.gov

-end-

Monday, 3 March 2008

Spaceflight Now | Breaking News | Lake Erie crew describes satellite shot

Lake Erie crew describes satellite shot:
 
ARMED FORCES PRESS SERVICE RELEASE
Posted: February 28, 2008
 
PEARL HARBOR, Hawaii - The crewmembers of the USS Lake Erie were calm as they fired the latest shot heard round the world. The Aegis-class cruiser fired the missile that destroyed a dead spy satellite that posed a threat to humans.
Navy Capt. Randall M. Hendrickson, the Lake Erie's commanding officer, spoke to reporters aboard the ship, which has just returned from the mission. The visiting reporters are traveling with Navy Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, who visited the ship.
The captain said the crew worked intensively for a month and a half before the shootdown. "We kept working up with a team of government experts and technicians, as well as industry partners," Hendrickson said.
The group worked to gather information and modify the Standard Missile 3 and the Aegis weapon system, he said. They started tracking the satellite at different times to get radar cross-section data, which helped build the program software, Hendrickson said.
"Obviously there was a lot of anticipation building up each time we practiced, each time we tracked," he said.
The ship's weapons systems officer, Navy Lt. Cmdr. Drew Bates, said the rehearsals really helped when push came to shove. "By the time we did this, we had seen it a hundred times," he said. "We were practicing what to do in case things go wrong. Fortunately nothing went wrong. This went just the way it was designed to happen, and hats off to the industry team for giving the nation a system that was able to have the excess capability to do this."
The satellite was unlike any target the system was designed to go after, the captain said. The satellite was in orbit rather than on a ballistic trajectory. Also, the satellite was traveling at incredible speeds.
The Lake Erie left here the day officials announced President Bush's decision to try to shoot down the satellite. Hendrickson said the ship was in position when the shuttle Atlantis returned from its mission.
The ship received the order that Defense Secretary Robert M. Gates had OK'd the mission at mid-morning. "From that point on, the ship was very calm," Hendrickson said. "Obviously, the closer we got, there was a lot of anticipation. The firing team was very calm when we did it and, with the exception of the Å’whoosh' when it went out of the launcher, it was just as scripted."
He said that when the missile's seeker opened its eyes it had the satellite "right dead center."
When the missile hit the satellite, "there was a lot of cheering" aboard the ship, he said.
The crew knew from the kinetic warhead imagery in the nose of the missile that it was a good hit, the captain said.
"The radar scope went wild," he said. "At that point, there was a lot of debris, a lot of pieces and, at that point, we thought we had a pretty good impact. Then that was confirmed by the aircraft that were airborne, the radars ashore and some other sensors that it was pretty much obliterated. Over the next three to four hours, a lot of it was burning up as it was coming down, which was the whole point of it."
Civilian experts from the Navy facility in Dahlgren, Va., and contractors from Lockheed Martin and from Raytheon Co. helped the crew prepare for the shot. But Navy sailors manned the consoles for the mission.
Everyone on the USS Lake Erie contributed, the captain said. "Whatever the task is, there's no small task on a ship," he said.
The reaction of the crew is unbelievable, said Command Master Chief Petty Officer Mack Ellis, the highest-ranking enlisted sailor on the Lake Erie. "Even the youngest sailor who didn't understand it at first, every time they walk somewhere and people know they are from Lake Erie, they say congratulations. It puts a smile of their face and makes their day".

Spaceflight Now | Breaking News | Spacecraft at Mars prepare for new kid on the block

Spacecraft at Mars prepare for new kid on the block:
 
NASA/JPL NEWS RELEASE
Posted: February 28, 2008
 
Three Mars spacecraft are adjusting their orbits to be over the right place at the right time to listen to NASA's Phoenix Mars Lander as it enters the Martian atmosphere on May 25.
Every landing on Mars is difficult. Having three orbiters track Phoenix as it streaks through Mars' atmosphere will set a new standard for coverage of critical events during a robotic landing. The data stream from Phoenix will be relayed to Earth throughout the spacecraft's entry, descent and landing events. If all goes well, the flow of information will continue for one minute after touchdown.
"We will have diagnostic information from the top of the atmosphere to the ground that will give us insight into the landing sequence," said David Spencer of NASA's Jet Propulsion Laboratory, Pasadena, Calif., deputy project manager for the Phoenix Mars Lander project.
This information would be valuable in the event of a problem with the landing and has the potential to benefit the design of future landers.
Bob Mase, mission manager at JPL for NASA's Mars Odyssey orbiter, said, "We have been precisely managing the trajectory to position Odyssey overhead when Phoenix arrives, to ensure we are ready for communications. Without those adjustments, we would be almost exactly on the opposite side of the planet when Phoenix arrives."
NASA's Mars Reconnaissance Orbiter is making adjustments in bigger increments, with one firing of thrusters on Feb. 6 and at least one more planned in April. The European Space Agency's Mars Express orbiter has also maneuvered to be in place to record transmissions from Phoenix during the landing. Even the NASA rovers Spirit and Opportunity have been aiding preparations, simulating transmissions from Phoenix for tests with the orbiters.
Launched on Aug. 4, 2007, Phoenix will land farther north than any previous mission to Mars, at a site expected to have frozen water mixed with soil just below the surface. The lander will use a robotic arm to put samples of soil and ice into laboratory instruments. One goal is to study whether the site has ever had conditions favorable for supporting microbial life.
Phoenix will hit the top of the Martian atmosphere at 5.7 kilometers per second (12,750 miles per hour). In the next seven minutes, it will use heat-shield friction, a parachute, then descent rockets to slow to about 2.4 meters per second (5.4 mph) before landing on three legs.
Odyssey will tilt from its normally downward-looking orientation to turn its ultrahigh-frequency (UHF) antenna toward the descending Phoenix. As Odyssey receives a stream of information from Phoenix, it will immediately relay the stream to Earth with a more capable high-gain antenna.
The other two orbiters, Mars Reconnaissance Orbiter and Mars Express, will record transmissions from Phoenix during the descent, as backup to ensure that all data is captured, then transmit the whole files to Earth after the landing.
"We will begin recording about 10 minutes before the landing," said JPL's Ben Jai, mission manager for Mars Reconnaissance Orbiter.
The orbiters' advance support for the Phoenix mission also includes examination of potential landing sites, which is continuing. After landing, the support will include relaying communication between Phoenix and Earth during the three months that Phoenix is scheduled to operate on the surface. Additionally, NASA and European Space Agency ground stations are performing measurements to determine the trajectory of Phoenix with high precision.
With about 160 million kilometers (100 million miles) still to fly as of late February, Phoenix continues to carry out testing and other preparations of its instruments. The pressure and temperature sensors of the meteorological station provided by the Canadian Space Agency were calibrated Feb. 27 for the final time before landing.
"The spacecraft has been behaving so well that we have been able to focus much of the team's attention on preparations for landing and surface operations," Spencer said.
The Phoenix mission is led by Peter Smith of the University of Arizona, Tucson, with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions are provided by the Canadian Space Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus, Denmark; the Max Planck Institute, Germany; and the Finnish Meteorological Institute. JPL, a division of the California Institute of Technology in Pasadena, manages Mars Odyssey and Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Tuesday, 26 February 2008

DefenseLink News Release: DoD Succeeds In Intercepting Non-Functioning Satellite

DefenseLink News Release: DoD Succeeds In Intercepting Non-Functioning Satellite


U.S. Department of Defense
Office of the Assistant Secretary of Defense (Public Affairs)
News Release
On the Web:
http://www.defenselink.mil/releases/release.aspx?releaseid=11704
Media contact: +1 (703) 697-5131/697-5132
Public contact:
http://www.defenselink.mil/faq/comment.html
or +1 (703) 428-0711 +1

IMMEDIATE RELEASE No. 0139-08
February 20, 2008

DoD Succeeds In Intercepting Non-Functioning Satellite

            A network of land-, air-, sea- and spaced-based sensors confirms that the U.S. military intercepted a non-functioning National Reconnaissance Office satellite which was in its final orbits before entering the earth's atmosphere.  
 
            At approximately 10:26 p.m. EST today, a U.S. Navy AEGIS warship,  the USS Lake Erie (CG-70), fired a single modified tactical Standard Missile-3 (SM-3) hitting the satellite approximately 247 kilometers (133 nautical miles) over the Pacific Ocean as it traveled in space at more than 17,000 mph. USS Decatur (DDG-73) and USS Russell (DDG-59) were also part of the task force.
 
            The objective was to rupture the fuel tank to dissipate the approximately 1,000 pounds (453 kg) of hydrazine, a hazardous fuel which could pose a danger to people on earth, before it entered into earth's atmosphere.   Confirmation that the fuel tank has been fragmented should be available within 24 hours.  
 
            Due to the relatively low altitude of the satellite at the time of the engagement, debris will begin to re-enter the earth's atmosphere immediately. Nearly all of the debris will burn up on reentry within 24-48 hours and the remaining debris should re-enter within 40 days.  
 
            DoD will conduct a press briefing at 7 a.m. EST to provide further information related to the operation. The briefing can be viewed live on www.Defenselink.com through the Pentagon Channel.      

DefenseLink News Article: Pentagon Opens Window of Time to Shoot Down Satellite

DefenseLink News Article: Pentagon Opens Window of Time to Shoot Down Satellite


American Forces Press Service


Pentagon Opens Window of Time to Shoot Down Satellite

By Gerry J. Gilmore
American Forces Press Service

WASHINGTON, Feb. 20, 2008 – The Pentagon has opened the window of time in which it will shoot down a malfunctioning U.S. reconnaissance satellite, a senior U.S. military officer said here today.

Today's return of the space shuttle Atlantis to Earth prompted the start of the optimal time period for shooting down the satellite, which extends until about the end of the month, the senior officer told Pentagon reporters.

Only "tens of seconds" will be available each day for a favorable launch of a ship-based SM-3 interceptor missile, the senior officer said. "The window is small, … but we're looking for the best orientation of the satellite" before launching the missile, the officer explained.

The 5,000-pound satellite malfunctioned soon after it was launched in 2006, making it unresponsive to ground control. It is carrying a tank full of hydrazine, a toxic rocket fuel. The satellite, orbiting every 90 minutes or so, was expected to fall to Earth in February or March with its tank of hydrazine intact, possibly endangering human populations.

President Bush directed the Defense Department to engage the satellite just before it enters the atmosphere at about 150 miles above the Earth. The goal is for the missile to hit and rupture the tank of rocket fuel, causing the hydrazine to burn up harmlessly in the atmosphere, along with debris from the stricken satellite.

About 50 percent of debris produced by the missile strike is expected to burn up during the stricken satellite's first two orbits after being hit, the senior military officer said, with the rest burning up shortly after.

Defense Secretary Robert M. Gates is to give the order to launch, based upon commanders' recommendations, the senior officer said. Gates will be advised as to the optimal time to launch by the commander of U.S. Strategic Command, based at Offutt Air Force Base, in Omaha, Neb.

All space sensor and missile-tracking activity related to the missile launch is being coordinated by the Joint Space Operations Center, at Vandenberg Air Force Base, Calif. Sensors, such as large radars and telescopes, are being coordinated by the Joint Integrated Missile Defense Team in Colorado Springs, Colo., under the U.S. Army's Space and Missile Defense Command.

Three U.S. Navy ships -- the cruiser USS Lake Erie and the destroyers USS Decatur and USS Russell -- are posted in the Pacific Ocean waiting for an optimal time to launch, the senior officer said. The Erie is slated to shoot at the satellite, and it is fitted with two SM-3 missiles. The Decatur has one, and the Russell has none. The missiles were modified to carry additional sensor equipment for the mission, the senior officer said.

The launch will be conducted during daytime over the Pacific, the senior officer explained, so that all sensors involved can better track the results of the missile launch. Necessary criteria for launch include satisfactory alignment of all pre-launch sensor-supplied data, as well as favorable weather conditions, he said.

Currently, the wave height about the ships is unfavorable to launch, the officer said. However, this and other conditions are subject to change, he added.

Related Sites:
U.S. Strategic Command

Related Articles:
Navy to Shoot Down Malfunctioning Satellite
Window to Open for Satellite Shoot-Down, Gates to Issue Order
Joint Space Operations Center Opens at Vandenberg

Wednesday, 20 February 2008

TOTAL LUNAR ECLIPSE FEBURARY 21st 2008

DON'T FORGET TO STAY UP TO THE EARLY HOURS TO VIEW THIS ONE-LETS HOPE FOR CLEAR SKIES......

Total Lunar Eclipse--Full Coverage

GOOD INFORMATION:
 
 
Space Weather News for Feb. 19, 2008
http://spaceweather.com

LUNAR ECLIPSE:  On Thursday morning, February 21st, the full Moon will turn a delightful shade of red and possibly turquoise, too. It's a total lunar eclipse—the last one until Dec. 2010.  Sky watchers in Europe, the Americas, parts of the Middle East and Africa are favored for good views of the two-hour event.  Visit http://spaceweather.com for full coverage including maps and timetables, live webcasts and discussion.


SPY SATELLITE UPDATE:  The US Navy's first attempt to hit malfunctioning spy satellite USA 193 with a missile could come on Wednesday night during the lunar eclipse.  This is based on an air traffic advisory warning pilots to steer clear of a patch of Pacific Ocean near Hawaii just when USA 193 is due to pass overhead. Until the satellite is shot down, it remains visible to casual sky watchers during evening passes over US and Canadian towns and cities; experienced observers say the decaying satellite is sometimes as bright as the stars of Orion, making it an easy target for unaided eyes and off-the-shelf digital cameras.  Details, photos and more information are available at http://spaceweather.com. Subscribers to Spaceweather PHONE (http://spaceweatherphone.com) will receive email and telephone alerts when the spy-sat is about to appear over their backyards.

Friday, 15 February 2008

Titan's Surface Organics Surpass Oil Reserves on Earth

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE  818-354-5011
http://www.jpl.nasa.gov

Carolina Martinez 818-354-9382
Jet Propulsion Laboratory, Pasadena, Calif.

NEWS RELEASE: 2008-025                          Feb. 13, 2008

Titan's Surface Organics Surpass Oil Reserves on Earth

Saturn's orange moon Titan has hundreds of times more liquid hydrocarbons than all the
known oil and natural gas reserves on Earth, according to new data from NASA's Cassini
spacecraft.  The hydrocarbons rain from the sky, collecting in vast deposits that form
lakes and dunes.

The new findings from the study led by Ralph Lorenz, Cassini radar team member from
the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., are reported in
the Jan. 29 issue of the Geophysical Research Letters.

"Titan is just covered in carbon-bearing material—it's a giant factory of organic
chemicals," said Lorenz. "This vast carbon inventory is an important window into the
geology and climate history of Titan."

At a balmy minus 179 degrees Celsius (minus 290 degrees Fahrenheit), Titan is a far cry
from Earth.  Instead of water, liquid hydrocarbons in the form of methane and ethane are
present on the moon's surface, and tholins probably make up its dunes.  The term
"tholins"was coined by Carl Sagan in 1979 to describe the complex organic molecules at
the heart of prebiotic chemistry.

Cassini has mapped about 20 percent of Titan's surface with radar. Several hundred lakes
and seas have been observed, with each of several dozen estimated to contain more
hydrocarbon liquid than Earth's oil and gas reserves.  The dark dunes that run along the
equator contain a volume of organics several hundred times larger than Earth's coal
reserves.

Proven reserves of natural gas on Earth total 130 billion tons, enough to provide 300
times the amount of energy the entire United States uses annually for residential heating,
cooling and lighting. Dozens of Titan's lakes individually have the equivalent of at least
this much energy in the form of methane and ethane.

"This global estimate is based mostly on views of the lakes in the northern polar regions.
We have assumed the south might be similar, but we really don't yet know how much
liquid is there," said Lorenz.  Cassini's radar has observed the south polar region only
once, and only two small lakes were visible.  Future observations of that area are planned
during Cassini's proposed extended mission.

Scientists estimated Titan's lake depth by making some general assumptions based on
lakes on Earth.  They took the average area and depth of lakes on Earth, taking into
account the nearby surroundings, like mountains.  On Earth, the lake depth is often 10
times less than the height of nearby terrain.

"We also know that some lakes are more than 10 meters or so deep because they appear
literally pitch-black to the radar. If they were shallow we'd see the bottom, and we don't,"
said Lorenz.

The question of how much liquid is on the surface is an important one because methane is
a strong greenhouse gas on Titan as well as on Earth, but there is much more of it on
Titan. If all the observed liquid on Titan is methane, it would only last a few million
years, because as methane escapes into Titan's atmosphere, it breaks down and escapes
into space. If the methane were to run out, Titan could become much colder. Scientists
believe that methane might be supplied to the atmosphere by venting from the interior in
cryovolcanic eruptions.  If so, the amount of methane, and the temperature on Titan, may
have fluctuated dramatically in Titan's past.

"We are carbon-based life, and understanding how far along the chain of complexity
towards life that chemistry can go in an environment like Titan will be important in
understanding the origins of life throughout the universe," added Lorenz.

Cassini's next radar flyby of Titan is on Feb. 22, when the radar instrument will observe
the Huygens probe landing site.

For images and more information visit: http://www.nasa.gov/cassini and
http://saturn.jpl.nasa.gov .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space
Agency and the Italian Space Agency. JPL, a division of the California Institute of
Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science
Mission Directorate, Washington. The Cassini orbiter was designed, developed and
assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency,
working with team members from the United States and several European countries.

-end-

Spy Satellite Sightings

Space Weather News for Feb. 14, 2008
http://spaceweather.com

Malfunctioning spy satellite USA 193 has been in the news lately because of expectations that it will reenter Earth's atmosphere in March and turn into a spectacular fireball.  Reentry has not yet begun, but sky watchers are already noticing the satellite as it zips over Europe and the United States shining as brightly as a first or second magnitude star. Typical photos are shown on today's edition of http://spaceweather.com.

In fact, USA 193 may never reenter--at least not in one piece. Today, the Pentagon announced it will attempt to blast the satellite with a missile before its orbit decays. This would lessen the chances of dangerous satellite debris and fuel reaching the ground while increasing the population of space junk in low-Earth orbit.

Would you like to see USA 193 with your own eyes?  It is about to make a series of evening appearances over many US towns and cities, beginning this weekend and continuing until the Pentagon intervenes. Flyby timetables may be found at Heavens Above (http://heavens-above.com). You can also receive telephone and email alerts when the satellite is about to fly over your backyard by subscribing to Spaceweather PHONE: http://spaceweatherphone.com .

Friday, 18 January 2008

SkyandTelescope.com - Homepage News - Reunion With Mercury

The planet Mercury and I go way back. In 1973, when NASA launched
Mariner 10 to pay it a visit, I was a Caltech undergrad working for
the head of the mission's imaging team. So I was on hand at the Jet
Propulsion Lab when the first-ever close-ups of Mercury came in the
following year.
A few months later I left California to join the staff of Sky &
Telescope. Mariner 10 would fly past the planet two more times, in
September 1974 and March 1975, and my first-ever bylined article in
S&T was a pictorial writeup following the second flyby. (If you've got
the November 1974 issue, look it up!)
What amazed me then, as now, is how Mercury looks superficially so
like the Moon — they both have scads of craters, giant impact basins,
and broad lava plains — and yet are so very different. Scientists
estimate that Mercury's metallic core takes up 75% of its radius and
nearly half its volume. How this "iron planet" came to exist remains
one of the great mysteries of planetary science.
The control room at Johns Hopkins University's Applied Physics
laboratory buzzed with activity during Messenger's first flyby of
Mercury on January 14, 2008.
S&T: J. Kelly BeattyFast forward to yesterday. NASA's Messenger
spacecraft was making the first return visit to Mercury in nearly 33
years (a third of a century, I remind myself), and I just had to be on
hand for the reunion. So I took a predawn flight from Boston to
Baltimore, then dashed over to the mission control center at Johns
Hopkins University's Applied Physics Laboratory for a ringside seat.
I'm thrilled to report that the flyby was 100% "nominal." At 2:04:39
p.m. Eastern time (19:04:39 Universal Time), out of view from both the
Sun and Earth, Messenger swept over the planet's night-side equator at
an altitude of just 125 miles (less than a mile higher than planned).
Taken by Messenger from about 17,000 miles away, this view of Mercury
shows about half of the area not photographed by Mariner 10 in
1974–75. The heavily cratered landscape is reminiscent of other areas
previously seen. The broad circular plain at upper right, appearing
brighter than its surroundings, marks the interior of Caloris basin, a
huge impact scar more than 800 miles across. Click on the image for a
full-resolution view.
NASA / JHU-APL / Carnegie Inst. of WashingtonThree minutes later it
emerged from hiding, reestablished contact with NASA's tracking
stations, and then sped off in blazing sunlight on a slightly altered
trajectory that will bring it 'round again on October 6th and yet a
third time in September 2009. During their fourth and final meeting,
in March 2011, Messenger will fire its braking rocket and settle into
orbit.
Messenger stands for MErcury Surface, Space ENvironment, GEochemistry,
and Ranging — an acronym of sorts no doubt created by NASA's
super-secret think tank for mission names. In any case, Messenger
carries an impressive array of scientific instruments — and all seven
of them were hard at work yesterday. You'll see the eye-popping
results here and at the mission's website in the days and weeks ahead.
Back in the mid-1970s, Mariner 10 left us with many unanswered
questions about Mercury. Why does it have a magnetic field? What's the
source of the tenuous atmosphere that envelops it? And are there
really deposits of ice at its poles?
Topping the list of questions is how Mercury came to be so iron-rich.
(In fact, after adjusting for compression effects, it's actually
denser than Earth.) Something happened at the dawn of solar-system
history that set this innermost planet distinctly apart from its
terrestrial siblings. As mission leader Sean Solomon confided to me
yesterday, "I want to learn how Mercury got put together."
So do I, Dr. Solomon — so do we all.

Posted by Kelly Beatty, January 15, 2008


Mercury: