[meteorite-list] Mars Express Commissioning and Early Results

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:08 2004
Message-ID: <200401232219.OAA15118_at_zagami.jpl.nasa.gov>

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=34487

Mars Express Commissioning and Early Results
European Space Agency
23 Jan 2004

Overall Mission Status

The Mars Express orbiter was successfully inserted into orbit around Mars
on 25 December 2003. Since then several manoeuvres have been performed
using the spacecraft?s main engine (plane turn manoeuvre and apocentre
reductions) and several further manoeuvres will be performed, using the
on-board thrusters, until the mapping orbit is reached on 28 January 2004.

The Mars Express spacecraft has continued to show nominal performance over
the past week with the payload and subsystems operating as expected. The
spacecraft's main engine has been isolated as it will not be used anymore. The
Beagle-2 lander was separated from the Mars Express orbiter on 19 December
and is assumed to have landed in Isidis Planitia on 25 December. However,
attempts to communicate with the lander have so far been unsuccessful.

Meanwhile, the orbiter scientific payload commissioning has started and the
payload instruments started returning their first scientific measurements from
Mars orbit. During this early phase, mostly dedicated to instrument checkout and
calibration, high-resolution stereo and colour images and high-resolution
spectral measurements of the planet are being acquired. The radio science
experiment has been obtaining its first scientific data from Mars (bistatic radar
measurements), and the MARSIS radar, which is scheduled for deployment at the
end of April 2004, will soon be conducting further checkout activities.

The early orbits of Mars Express, until about mid-February 2004, represent the
best opportunity for optimised observing conditions (illumination, targets of
interest, distance to the Sun, lack of eclipses) and, therefore, maximum science
return.

The planning of the next payload commissioning activities and science operations
are progressing nominally. Payload activity timelines are being prepared for the
next few weeks, with the goal of optimising the scientific return while keeping
within the limits of the power budget.

Science Results

19 January 2004
HRSC
The first science result showed the Valles Marineris
canyon system in stunning detail. Valles Marineris is a
giant canyon system stretching 4000 km across the surface
of the planet. At its start and end it is 2 km deep and in
the middle it is 7 km deep and 600 km wide.

23 January 2004
OMEGA
Analysis of data acquired over the southern polar cap on 18
January has revealed the existence of trapped water ice
along with carbon dioxide ice.

PFS
PFS data has shown that there is an inbalance to the
distribution of carbon dioxide on Mars.

HRSC
HRSC has now imaged an area of the Martian surface
covering 1.87 million km2. This corresponds to 100
Gigabytes of data! The camera images a single track up to
4000 km in length (roughly the size of the United States
from coast to coast). A series of stunning images have
been released revealing river channels, dust falling over a
cliff edge and erosion features.

SPICAM
A unique measurement was made with SPICAM. By observing a star twice,
once through the atmosphere and once with no atmosphere present, it was
possible to analize the Martian atmosphere. This has enabled measurements to
be made on the distribution of the ozone and water vapour revealing that there
is more water vapour where there is less ozone.


Orbit and Surface Coverage Information

The orbit of the Mars Express spacecraft is very stable. Several more apocentre
reduction manoeuvres will be conducted in order to reach the selected mapping
orbit on 28 January.

The early scientific planning is driven by the opportunity to take images and
spectral measurements of a number of targets of interest under excellent
observing conditions. The current observations cover a variety of essential
Martian surface features and targets of interest: volcanic terrains, chaotic terrains
near Valles Marineris, Isidis Planitia with the Beagle-2 landing site, and the
Spirit landing site (Gusev Crater). Later on, once the mapping orbit is achieved,
the focus of science data acquisition will be extended to global coverage, mosaic
and map construction, and high-resolution imaging and spectral mapping of
selected local surface targets.

Scientific Payload Status and Measurements

The status and performance summarised in the following table

 Instrument Activities Status/Performance
 ASPERA Calibrations (completed) Nominal
 HRSC/SRC Nadir-pointed stereo and colour imaging Nominal
 MARSIS None Checkout next week
 OMEGA Nadir-pointed hyperspectral measurements Nominal
 PFS Nadir-pointed spectral measurements Nominal
 SPICAM Nadir and star occultation observations Nominal

During the past week a number of nadir-pointed and inertial observations were
made. Stereo and colour images, multi/hyper-spectral visible and near-infrared
data sets, and UV-infrared spectra were acquired and delivered by the
HRSC/SRC, OMEGA, PFS and SPICAM instruments on board the orbiter. This
first set of Mars Express scientific data, containing some of the highest spatial
and spectral resolutions ever obtained and returned from Mars orbit, is already
revealing important information about Martian surface features, in particular in the
chaotic and volcanic regions, outflow channel areas, and near the crustal
dichotomy boundary.
Received on Fri 23 Jan 2004 05:19:17 PM PST