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NEWS • MISSION UPDATE
SPACE SHORTS
MRO approaches Mars
Mars Reconnaissance Orbiter,
NASA’s most ambitious Mars
spacecraft, should reach its orbit
this month, ready for mapping of
the surface and atmosphere,
looking out especially for signs of
water and ice. It carries a
powerful camera, able to pick out
boulders the size of a small desk,
plus radar to seek out subsurface
ice and water, and a mineral
mapper. A weather camera will
cover the whole planet each day,
and an IR sounder will track
atmospheric temperatures and
the movement of water vapour.
MRO’s fast data-transmission
capability will support future
surface missions such as the
Phoenix Mars Scout and the
Mars Science Laboratory.
http://www.nasa.gov/mro
Dawn cancelled
The spacecraft Dawn, built and
almost ready for its launch to
observe asteroids Vesta and
Ceres, will not be taking off. The
mission has been cancelled as
part of NASA’s budget problems.
NASA is focusing on the International Space Station and the
preparation of the Crew
Exploration Vehicle. Dawn was
to have been launched in June
this year as the ninth mission of
NASA’s Discovery programme.
New Horizons
NASA’s New Horizons
spacecraft was launched
successfully in January, and
should reach Pluto in 2015. New
Horizons set off as the fastest
spacecraft yet launched, and will
need a gravity assist from
Jupiter to send it on its way. If
successful at Pluto, there is the
chance for further exploration of
more distant and unknown
objects in the Kuiper Belt
beyond, in an extended mission.
IMAGE fades
The successful IMAGE orbiter,
NASA’s Imager for Magnetopause-to-Aurora Global
Exploration satellite, stopped
working in December 2005,
apparently because of a power
failure. IMAGE had a successful
six-year life, following a two-year
primary mission, providing
images that allowed researchers
to track the global structure and
dynamics of the Earth’s inner
magnetosphere as it responded
to energy from the solar wind.
http://www.image.gsfc.nasa.gov
2.8
Mission update
There’s continuing activity and
more discoveries from the likes of
Spitzer, XMM-Newton, FUSE and
Swift, but it’s not all good news for
space missions.
Discs like Kuiper
Belt on steroids
The Spitzer Space Telescope has
found supersize discs of dust around
huge stars, raising the possibility
that, even in the hostile environment
around such massive hot stars, planets could be forming. Spitzer detected
enormous amounts of dust around
two hypergiant stars, R 66 and
R 126, in the Large Magellanic
Cloud. They are 30 and 70 times the
mass of the Sun, respectively. If such
a star were located at the Sun’s position in our solar system, all the inner
planets, including Earth, would fit
comfortably within its circumference.
Their discs are equally outsize, reaching as far as around 60 times the
orbit of Pluto.
The discs contain silicates and that
around R 66 showed signs of dust
clumping in the form of silicate crystals and larger dust grains. Such
clumping can be a significant step in
the construction of planets.
Dusty discs around stars – like our
Kuiper Belt – are thought to represent
the start or finish of the planetforming process. If the latter, these
huge discs are the equivalent of our
Kuiper Belt on a tremendous scale.
But such dusty discs also hold out
hope that planet-forming processes
are robust. They suggest that planets
could form even around tremendously hot stars with powerful stellar
winds.
Joel Kastner of the Rochester Institute of Technology in New York is
first author of a paper describing the
research in the 10 February issue of
Astrophysical Journal Letters.
http://www.spitzer.caltech.edu/spitzer
Pulsar winds
illuminated
ESA’s XMM-Newton spacecraft has
shown astronomers what happens
when a pulsar meets a ring of gas
around a neighbouring star. The rare
passage illuminated the sky in
gamma- and X-rays, allowing
astronomers a better understanding
of the mysterious origin and content
of “pulsar winds” and “pulsar nebulae”, such as the colourful Crab and
1: This 50cm wide laser beam, emitted from the VLT in Chile, forms an
artificial guide star when it hits sodium atoms 90km above the Earth.
Vela pulsars. The analysis is based on
new observations from XMMNewton and archived data. The team
observed
the
radio
pulsar
PSR B1259-63 orbiting a bright “Be”
star named SS 2883. Lead author
Masha Chernyakova, of the Integral
Science Data Centre, Versoix,
Switzerland, said: “Here we had the
rare opportunity to see pulsar wind
clashing with stellar wind. It is analogous to smashing something open to
see what’s inside.” The results are
published in the Monthly Notices of
the Royal Astronomical Society.
http://www.esa.int/esaSC/SEMK6HMVGJ
E_index_0.html
Artificial star aids
adaptive optics
Adaptive optics at the European
Southern Observatory took a major
step forward in January with the initiation of the first laser guide star in
the southern hemisphere. The artificial star is formed by a 50 cm wide,
yellow laser beam meeting a layer of
sodium atoms at an altitude of
90 km. The atoms glow to produce a
faint artificial star that will allow
adaptive optics systems to measure
and correct the blurring effect of
atmospheric turbulence. Other adaptive optics systems use a bright star to
correct for atmospheric effects, but
this limits observations to parts of the
sky that are near bright stars. ESO’s
artificial star means that astronomers
are no longer limited in this way.
The high-power laser beam originates from a launching telescope on
Yepun, the fourth 8.2 m Unit Telescope of the Very Large Telescope,
based at Cerro Paranal, Chile (figure
1). Five years of collaborative work
by scientists and engineers from ESO
A&G • April 2006 • Vol. 47