SpaceX Dragon Attached to Space
Station in Spaceflight First
 05.25.12
The
International Space Station's Expedition 31 crew grappled and attached
SpaceX's Dragon capsule to the space station Friday. This is the first
time a commercial company has accomplished this type of space operation.
"Today marks another critical step in the future of American
spaceflight," NASA Administrator Charles Bolden said. "Now that a U.S.
company has proven its ability to resupply the space station, it opens a
new frontier for commercial opportunities in space -- and new job creation
opportunities right here in the U.S. By handing off space station
transportation to the private sector, NASA is freed up to carry out the
really hard work of sending astronauts farther into the solar system than
ever before. The Obama Administration has set us on an ambitious path
forward and the NASA and SpaceX teams are proving they are up to the
task."
Following a series of system tests and a successful
fly-under of the space station Thursday, the Dragon capsule was cleared by
NASA to approach the station Friday. Dragon then performed a series of
intricate test maneuvers as it approached the orbiting laboratory. These
maneuvers were required to demonstrate the maneuvering and abort
capability of Dragon prior to approaching and moving into a 65-foot
(20-meter) "berthing box" where it was grappled by NASA astronaut Don
Pettit using the station's robotic arm at 9:56 a.m. EDT.
European
Space Agency astronaut Andre Kuipers installed the capsule on the bottom
of the station's Harmony node at 11:52 a.m. NASA astronaut Joe Acaba
completed berthing operations by bolting the Dragon to
Harmony at 12:02 p.m.
The
Dragon capsule lifted off Tuesday from the Cape Canaveral Air Force
Station in Florida aboard a SpaceX Falcon 9 rocket. The demonstration
mission is the second under NASA's Commercial Orbital Transportation
Services program, which provides investments intended to lead to regular
resupply missions to the space station and stimulate the commercial
space industry in America.
The Dragon
capsule is delivering 1,014 pounds of supplies to the station, which
includes non-critical experiments, food, clothing and technology. Crew
members will open the hatch to the capsule Saturday and unload the cargo
during a four-day period. Dragon then will be loaded with 1,367 pounds of
hardware and cargo no longer needed aboard the station in preparation for
the spacecraft's return to Earth. Dragon and station hatches will be
closed on May 30.
On May 31, the Expedition 31 crew members will detach
Dragon from Harmony, maneuver it to a 33-foot release point and un-grapple
the capsule. Dragon will deorbit approximately four hours after leaving
the station, taking about 30 minutes to re-enter Earth's atmosphere and
landing in the Pacific Ocean about 250 miles west of southern California.
Cassini Spots Tiny Moon, Begins to Tilt
Orbit
 05.21.12
NASA's Cassini spacecraft made its closest approach to Saturn's tiny
moon Methone as part of a trajectory that will take it on a close flyby of
another of Saturn's moons, Titan. The Titan flyby will put the spacecraft
in an orbit around Saturn that is inclined, or tilted, relative to the
plane of the planet's equator. The flyby of Methone took place on May 20
at a distance of about 1,200 miles (1,900 kilometers). It was Cassini's
closest flyby of the 2-mile-wide (3-kilometer-wide) moon. The best
previous Cassini images were taken on June 8, 2005, at a distance of about
140,000 miles (225,000 kilometers), and they barely resolved this object.
Also on May 20, Cassini obtained images of Tethys, a larger Saturnian
moon that is 660 miles (1,062 kilometers) across. The spacecraft flew by
Tethys at a distance of about 34,000 miles (54,000 kilometers).
Cassini's encounter with Titan, Saturn's largest moon, on May 22, is
the first of a sequence of flybys that will put the spacecraft into an
inclined orbit. At closest approach, Cassini will fly within about 593
miles (955 kilometers) of the surface of the hazy Titan. The flyby will
angle Cassini's path around Saturn by about 16 degrees out of the
equatorial plane, which is the same plane in which Saturn's rings and most
of its moons reside.
 Cassini's onboard thrusters
don't have the capability to place the spacecraft into orbits so inclined.
But mission designers have planned trajectories that take advantage of the
gravitational force exerted by Titan to boost Cassini into inclined
orbits. Over the next few months, Cassini will use several flybys of Titan
to change the angle of its inclination, building one on top of the other
until Cassini is orbiting Saturn at around 62 degrees relative to the
equatorial plane in 2013. Cassini hasn't flown in orbits this inclined
since 2008, when it orbited at an angle of 74 degrees.
This set of inclined orbits is expected to provide spectacular views of
the rings and poles of Saturn. Further studies of Saturn's other moons
will have to wait until around 2015, when Cassini returns to an equatorial
orbit.
Cassini discovered Methone and two other small moons,
Pallene and Anthe, between the orbits of Mimas and Enceladus between 2004
and 2007. The three tiny moons, called the Alkyonides group, are embedded
in Saturn's E ring, and their surfaces are sprayed by ice particles
originating from the jets of water ice, water vapor and organic compounds
emanating from the south polar area of Enceladus.
Images credit: NASA/JPL-Caltech/SSI
Cassini Finds Saturn
Moon has Planet-Like Qualities
04.26.12
PASADENA, Calif. -- Data from NASA's Cassini mission reveal Saturn's
moon Phoebe has more planet-like qualities than previously thought.
Scientists had their first close-up look at Phoebe when Cassini began
exploring the Saturn system in 2004. Using data from multiple spacecraft
instruments and a computer model of the moon's chemistry, geophysics and
geology, scientists found Phoebe was a so-called planetesimal, or remnant
planetary building block. The findings appear in the April issue of the
Journal Icarus.
"Unlike primitive bodies such as comets, Phoebe appears to have
actively evolved for a time before it stalled out," said Julie
Castillo-Rogez, a planetary scientist at NASA's Jet Propulsion Laboratory
in Pasadena, Calif. "Objects like Phoebe are thought to have condensed
very quickly. Hence, they represent building blocks of planets. They give
scientists clues about what conditions were like around the time of the
birth of planets and their moons."
Cassini images suggest Phoebe originated in the far-off Kuiper Belt,
the region of ancient, icy, rocky bodies beyond Neptune's orbit. Data show
Phoebe was spherical and hot early in its history, and has denser
rock-rich material concentrated near its center. Its average density is
about the same as Pluto, another object in the Kuiper Belt. Phoebe likely
was captured by Saturn's gravity when it somehow got close to the giant
planet.
Saturn is surrounded by a cloud of irregular moons that circle the
planet in orbits tilted from Saturn's orbit around the sun, the so-called
equatorial plane. Phoebe is the largest of these irregular moons and also
has the distinction of orbiting backward in relation to the other moons.
Saturn's large moons appear to have formed from gas and dust orbiting in
the planet's equatorial plane. These moons currently orbit Saturn in that
same plane.
Analyses suggest that Phoebe was born within the first 3 million years
of the birth of the solar system, which occurred 4.5 billion years ago.
The moon may originally have been porous but appears to have collapsed in
on itself as it warmed up. Phoebe developed a density 40 percent higher
than the average inner Saturnian moon.
Objects of Phoebe's size have long been thought to form as
"potato-shaped" bodies and remained that way over their lifetimes. If such
an object formed early enough in the solar system's history, it could have
harbored the kinds of radioactive material that would produce substantial
heat over a short timescale. This would warm the interior and reshape the
moon.
Phoebe started with a nearly spherical
shape, rather than being an irregular shape later smoothed into a sphere
by impacts," said co-author Peter Thomas, a Cassini team member at
Cornell.
Phoebe likely stayed warm for tens of millions of years before freezing
up. The study suggests the heat also would have enabled the moon to host
liquid water at one time. This could explain the signature of water-rich
material on Phoebe's surface previously detected by Cassini.
The new study also is consistent with the idea that several hundred
million years after Phoebe cooled, the moon drifted toward the inner solar
system in a solar-system-wide rearrangement. Phoebe was large enough to
survive this turbulence.
Image credit: NASA/JPL/Space Science
Institute
Orion Ground Test Vehicle Arrives at
Kennedy
 The Orion Ground Test Vehicle
arrived at NASA's Kennedy Space Center Operations & Checkout (O&C)
Facility on April 21. The vehicle traveled more than 1,800 miles from
Lockheed Martin's Waterton Facility near Denver, Colo., where it
successfully completed a series of rigorous acoustic, modal and vibration
tests that simulated launch and spaceflight environments.
The ground
test vehicle will now be used for pathfinding operations at the O&C in
preparation for the Orion spaceflight test vehicle's arrival this
summer.
Image Credit: NASA
The pit-chains of Mars – a possible place for
life?
5 April 2012
The latest images released from ESA’s Mars Express reveal a series of
‘pit-chains’ on the flanks of one of the largest volcanoes in the Solar
System. Depending on their origin, they might be tempting targets in the
search for microbial life on the Red Planet.
The images, taken on
22 June 2011, cover Tractus Catena in the Arcadia quadrangle, part of the
vast Tharsis region on Mars. This region boasts a number of huge
volcanoes, including the three collectively known as Tharsis Montes. To
their north sits Alba Mons, also known as Alba Patera, one of the largest
volcanoes in the Solar System by area and volume.
Tractus Catena sits on its southeastern flank of Alba Mons and the
pit-chains in that region are a series of circular depressions that formed
along fracture points in the martian crust.
Pit-chains can have a volcanic origin. Lava streaming from a volcano
solidifies on the surface, leaving a molten tube of lava running below.
Once volcanic activity ceases, the tube empties, leaving behind a
subterranean cavity. Over time, parts of the roof over the cavity may
collapse, leaving circular depressions on the surface. On Earth, recent
examples can be seen on the flanks of Kilauea volcano in Hawaii, while on
the Moon, Hadley Rille, visited by Apollo 15 in 1971, is believed to have
formed in the same way billions of years ago.
Credits: ESA/DLR/FU Berlin (G. Neukum)
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