Download Magnetic traces in meteorites

News • Mission Update
Space Shorts
India’s off to the Moon
Chandrayaan-1, India’s first
Moon mission, was launched
successfully from the Satish
Dhawan Space Centre (SHAR)
in Sriharikota, off India’s Andhra
Pradesh coast, on the morning
of 22 October. It since moved
into increasingly elliptical
orbits around Earth, while its
performance is monitored, and
then set off on its way to the
Moon. Once there, it will take
up a polar lunar orbit at 100 km
altitude, before releasing the
Moon Impact Probe.
http://www.chandrayaan-i.com/
Hang on Hubble
The Hubble servicing mission
will be delayed again because
a replacement data handling
unit will not be ready in time for
the proposed February launch
date. The unit, known as the
Science Instrument Command
and Data Handling system, failed
in September. Its replacement
has been stored at the Goddard
Space Flight Center since 1991,
as a back-up, but needs more
testing than is possible to be
ready for February. The other
equipment to be sent to the HST
on this servicing mission, such as
the Wide Field Camera 3, and the
Cosmic Origins Spectrograph,
will remain packaged ready
to go, with some attention to
batteries and lubrication.
http://hubble.nasa.gov
Delay for GOCE
ESA’s GOCE satellite (Gravity
field and steady-state Ocean
Circulation Explorer) has had
its launch delayed until at least
February 2009 because of a fault
in the Russian Rockot launcher.
An anomaly in the guidance
system requires hardware
changes that will take at least
two months to implement.
When in orbit, GOCE will map
Earth’s gravity field in detail for
around 20 months, producing
a much improved model of the
geoid, useful for solid Earth
and ocean science, as well as
for mapping sea-level change
and for precision surveying. It is
an innovative mission in many
ways, not least in that it employs
gradiometry – measurements
from ultrasensitive
accelerometers – to measure
the variations in the gravitational
field as the spacecraft orbits the
Earth at just 250 km altitude.
http://www.esa.int/esaLP/LPgoce.html
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Mission update
1: Mercury has given
up more of its secrets
to Messenger in the
recent flyby, but there
remains 5% of the
surface that hasn’t
been observed by
either Messenger or
Mariner 10. So far,
Mercury is proving
remarkably different
from the other
terrestrial planets
(NASA/Johns Hopkins
University Applied
Physics Laboratory/
Carnegie Institution of
Washington)
Messenger
revisits Mercury
The NASA spacecraft Messenger
has taken the opportunity of a second swing past Mercury in preparation for going into orbit around the
planet to explore more of the previously unseen surface in its western
hemisphere (figure 1). Messenger’s
camera, laser altimeter, magnetometer and spectrometer were collecting
data during the flyby, adding to the
haul from the previous fly-past and
from Mariner 10.
The images and topography from
both of Messenger’s close encounters
overlapped so that mission scientists
now have a much better correlation between surface appearance
and shape, which will aid future
geological interpretation of surface
data. And the magnet­ometry showed
that Mercury’s magnetic field so far
measured is symmetrical in eastern
and western hemispheres.
The Mercury Atmospheric and
Surface Composition Spectrometer observed Mercury’s exosphere
– its thin atmosphere – looking for
sodium, calcium, magnesium and
hydrogen atoms. First results suggest
that sodium, calcium and magnesium
– an element detected around Mercury for the first time by Messenger
– have different spatial distributions
around the planet, hinting at varied
processes perhaps in the interaction
between surface and exosphere.
Now that researchers have seen
95% of Mercury’s surface (combining Messenger’s data on 80% of the
surface with that of Mariner 10) it is
clear that the planet is very different
from the Moon and Mars. Mercury’s
surface is typically homogeneously
ancient and heavily cratered.
charging within a few hours, without any loss of capability. The problem may have arisen because it was
colder than usual at the landing site,
meaning that the battery heaters
were used, drawing more power at
a time when dust storms and ice on
the atmosphere were decreasing the
solar power available.
Phoenix was to sit tight and build
up power supplies before attempting
any more science tasks.
http://www.nasa.gov/phoenix
Magnetic traces
Phoenix lander in meteorites
plays it safe
Traces of magnetic fields in some
http:// www.nasa.gov/messenger
NASA’s Mars lander Phoenix went
into safe mode for a short time at
the end of October, thought to be
a response to low power resulting
from low surface temperatures and
decreased sunlight around the north
pole. In this state, the lander stops
any activities not considered critical;
in this case Phoenix also switched off
one of its batteries and changed to a
redundant set of electronics.
Mission engineers were able to
contact the lander and restart battery
ancient meteorites suggest that planetesimals formed in the early stages
of the life of the solar system may
have been big enough to have melted,
differentiated and formed magnetic
dynamos. Some of the angrites, a
class of iron meteorites formed early
in the evolution of the solar system,
show signs that their parent bodies
had magnetic fields around 20–40%
as strong as Earth’s field today.
These samples formed in the first
3 million years of the solar system’s
lifetime, suggesting not only that the
A&G • December 2008 • Vol. 49
News • Mission Update
Hubble gets back to business
Space Shorts
Armstrong archived
The astronaut Neil Armstrong
has given his personal papers to
the university where he gained
his degree in aeronautical
engineering, where they will
be kept as a record of his
career. Purdue University, West
Lafayette, Indiana, USA, will
keep the archive, together with
55 hours of interviews prepared
for a biography of Armstrong,
as a resource for scholars. It is
seeking comparable information
from other people involved in
the spaceflight programme, in
order to build a comprehensive
collection. Purdue also holds
the George Palmer Putnam
Collection of Amelia Earhart
Papers, and the papers of Ralph
Johnson, who was the first
person to document aircraft
landing procedures that are still
used today.
School payload
This image of the interacting galaxy pair Arp 147 was taken by the Wide Field Planetary Camera 2 after the
Hubble Space Telescope came back online after an equipment failure in September this year. The fault was
managed by transferring processing tasks to a part of the HST unused and untested since its launch in 1990.
This image is testament to the success of the process, taken a couple of days after the reboot. It is a composite of
three colour images – blue, green and red indicating blue, visible light and infrared radiation respectively – and
demonstrates that the camera is working as it was before the fault became apparent. This pair of galaxies were
listed by Halton Arp in his Catalogue of Peculiar Galaxies, published in 1966. The galaxy on the left, aligned roughly
edge-on, has passed through the galaxy on the right, leaving behind a blue ring of intense star formation,
triggered by the galaxy “impact”. The dusty reddish knot at the lower left of the blue ring probably marks the
location of the original nucleus of the galaxy that was hit. (NASA, ESA, M Livio [STScI])
A satellite currently being built by
Surrey Satellite Technology Ltd has gained an extra experiment,
thanks to a school competition
sponsored by the British National
Space Centre. The challenge was
to design an instrument to fit in a
lunchbox-sized space, weighing
no more than a kilogram and
using less than 1 W of power. Shrewsbury School won with an
ionospheric experiment called
POISE, which should fly in 2010.
http://www.bnsc.gov.uk
relatively small bodies existing then
had melted and differentiated enough
to produce a dynamo effect, but that
they did so very quickly. It may be
that these short-lived planetary
dynamos were widespread among
the planetesimals of the early solar
system, which has implications for
the processes of collision and assimilation considered important in the
development of the planetary system
we know today. The results were
published in Science, 31 October.
COROT catches
shaking stars
COROT, a joint mission of the
French Space Agency (CNS) and the
European Space Agency, has directly
observed “stellar seismology” data
from three stars similar to the Sun,
for the first time.
Detecting fluctuations in brightness that arise from these internal
oscillations is tricky, made easier by
space-based observation, which is
A&G • December 2008 • Vol. 49 not interrupted by the rotation of the
Earth nor by weather. The patterns of
oscillation of the sound waves within
a star reveals information about its
internal structure and the transfer of
energy from the interior to the surface. And information from several
stars like the Sun will also aid understanding of the Sun itself. The three
stars probed by COROT – HD49933,
HD181420 and HD181906 – are similar to the Sun, but far enough away
for their light not to blind COROT’s
instruments.
The research was published in
Nature by lead author E Michel.
http://www.esa.int
SST spies twin
solar system
The Spitzer Space Telescope has
found a pair of rocky asteroid belts
in a nearby planetary system, with
the inner one almost the same as the
asteroid belt in our solar system, plus
an outer icy belt. The implication is
that planets between these belts are
confining and shaping them, as happens around the Sun.
e Eridani is a slightly smaller and
cooler star than the Sun, just 10.5
light-years away. It is considered a
close analogue of our solar system
when young, at the time when life
was beginning on Earth. Our asteroid belt has around 5% of the mass
of Earth’s Moon in it, and orbits
at 3 AU; e Eridani has an identical
belt at the same distance, plus one
at around 20 AU, roughly where
Uranus is in our system. And the
icy outer belt corresponds to the
Edgeworth–Kuiper belt, but in a
state before much of the material was
swept further into the solar system in
the Late Heavy Bombardment.
The gaps between the rings strongly
suggest that there are planets there
– and three planets with masses
between those of Neptune and Jupiter would fit the observations nicely.
This work will be published in the
10 January issue of the Astrophysical Journal.
CESAR rules rovers
An ESA contest to find the
best rover to venture into a
lunar crater has been won by a
Bremen University team with
their rover CESAR. ESA set the
first Lunar Robotics Challenge
within Tenerife’s Teide National
Park, a bleak pumice landscape
comparable to the Moon. Rovers
had to descend into and escape
from a 15 m crater with 40%
slopes, and pick out soil from
a specific location, in the dark.
The challenge also covered
control of the rovers and tested
other potential technology
for ESA’s space programme.
Heavy rain and clouds provided
a distinctly terrestrial tinge
to the challenge, and all the
competing teams learnt from
the experience, which ESA
hopes to repeat. The University
of Surrey’s SELENE was unable to join in because of
mechanical failure.
http://www.esa.int
http://www.cfa.harvard.edu
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