Jacques van Oene
November 29th 04, 10:11 PM
Mars Express Status Report - November 2004
29 Nov 2004 16:46
Mission Status
Following a successful period of science data taking in July and early
August, end-August and most of September were dominated by a solar
conjunction. In such a situation Mars is located diagonally across the Sun,
as seen from Earth. Such a constellation blocks efficient radio
communications and the spacecraft was prepared to survive extended periods
of no contact. In this period almost no science data could be taken. On the
egress from conjunction all spacecraft systems were nominal.
Studies on the safe deployment of the radar antenna for the MARSIS
experiment are approaching completion, and expected to lead to clear
conclusions in the last quarter of 2004. In parallel it has been decided
that the earliest deployment window, based on both technical and scientific
grounds, starts around mid-March 2005.
Operations and archiving
Operations planning up to the end of the year is progressing steadily. With
the Mars-Earth distance still being high, and consequently a low-bit rate on
the telecommunications link, there is only a limited data volume which can
be downlinked. Together with the other mission constraints this sometimes
leads to difficult trade-offs in the distribution of observations over the
instruments.
The independent Mars Express Science Archive Review was held on 12-13 July
at ESTEC. Although a number of actions to be taken were identified, the
review was judged to have been extremely valuable by all involved.
Science highlights
A dedicated Mars Express Science Conference will take place at ESTEC on the
week of 21-25 February 2005.
A very successful international Mars conference was held in Ischia, Italy
from 19-23 September 2004. A significant number of recent results from
Mars-Express were presented, as summarized hereafter.
It is generally believed, and indicated by results from the High Resolution
Stereo Camera (HRSC), there once were abundant fluvial activities active on
Mars. However, even though recent OMEGA observations confirm that today
water still exists as vast fields of perennial water ice, stretching out
from its South pole, an efficient mechanism for removing water from the
planet must have been at work. Recent results from the ASPERA instrument on
board Mars Express confirm that such a process is at work in the Martian
atmosphere, explaining the loss of water over time. It is believed the solar
wind erodes the atmosphere of Mars, and strips away large amounts of water
that were present on the planet about 3.8 billion years ago. The ASPERA
instrument on board Mars Express has measured a process called 'solar wind
scavenging', or the slow 'invisible' escape of volatile gases and liquid
compounds which make up the atmosphere and hydrosphere of a planet. These
measurements have established that the solar wind penetrates through the
ionosphere and very deeply into the Martian atmosphere down to an altitude
of 270 kilometres. This seems to be the reason for the acceleration
processes that could explain the loss of atmosphere on Mars.
Measurements by the Planetary Fourier Spectrometer (PFS) reveal that, at
10-15 kilometres above the surface, water vapour is well mixed and uniform
in the atmosphere. However, it found that, close to the surface, water
vapour is more concentrated in three broad equatorial regions. Here, the
concentration is two to three times higher than in other regions observed.
New in-depth analysis of PFS data shows that methane is not uniform in the
atmosphere, but concentrated in some areas. The PFS team observed that the
areas of highest concentration of methane overlap with areas where water
vapour and underground water ice are also concentrated. This spatial
correlation between water vapour and methane seems to point to a common
underground source. Further investigations are needed to fully understand
the correlation between (i) presence and distribution of water vapour and
methane in the atmosphere and (ii) the presence of a subsurface ice layer.
--
--------------
Jacques :-)
www.spacepatches.info
29 Nov 2004 16:46
Mission Status
Following a successful period of science data taking in July and early
August, end-August and most of September were dominated by a solar
conjunction. In such a situation Mars is located diagonally across the Sun,
as seen from Earth. Such a constellation blocks efficient radio
communications and the spacecraft was prepared to survive extended periods
of no contact. In this period almost no science data could be taken. On the
egress from conjunction all spacecraft systems were nominal.
Studies on the safe deployment of the radar antenna for the MARSIS
experiment are approaching completion, and expected to lead to clear
conclusions in the last quarter of 2004. In parallel it has been decided
that the earliest deployment window, based on both technical and scientific
grounds, starts around mid-March 2005.
Operations and archiving
Operations planning up to the end of the year is progressing steadily. With
the Mars-Earth distance still being high, and consequently a low-bit rate on
the telecommunications link, there is only a limited data volume which can
be downlinked. Together with the other mission constraints this sometimes
leads to difficult trade-offs in the distribution of observations over the
instruments.
The independent Mars Express Science Archive Review was held on 12-13 July
at ESTEC. Although a number of actions to be taken were identified, the
review was judged to have been extremely valuable by all involved.
Science highlights
A dedicated Mars Express Science Conference will take place at ESTEC on the
week of 21-25 February 2005.
A very successful international Mars conference was held in Ischia, Italy
from 19-23 September 2004. A significant number of recent results from
Mars-Express were presented, as summarized hereafter.
It is generally believed, and indicated by results from the High Resolution
Stereo Camera (HRSC), there once were abundant fluvial activities active on
Mars. However, even though recent OMEGA observations confirm that today
water still exists as vast fields of perennial water ice, stretching out
from its South pole, an efficient mechanism for removing water from the
planet must have been at work. Recent results from the ASPERA instrument on
board Mars Express confirm that such a process is at work in the Martian
atmosphere, explaining the loss of water over time. It is believed the solar
wind erodes the atmosphere of Mars, and strips away large amounts of water
that were present on the planet about 3.8 billion years ago. The ASPERA
instrument on board Mars Express has measured a process called 'solar wind
scavenging', or the slow 'invisible' escape of volatile gases and liquid
compounds which make up the atmosphere and hydrosphere of a planet. These
measurements have established that the solar wind penetrates through the
ionosphere and very deeply into the Martian atmosphere down to an altitude
of 270 kilometres. This seems to be the reason for the acceleration
processes that could explain the loss of atmosphere on Mars.
Measurements by the Planetary Fourier Spectrometer (PFS) reveal that, at
10-15 kilometres above the surface, water vapour is well mixed and uniform
in the atmosphere. However, it found that, close to the surface, water
vapour is more concentrated in three broad equatorial regions. Here, the
concentration is two to three times higher than in other regions observed.
New in-depth analysis of PFS data shows that methane is not uniform in the
atmosphere, but concentrated in some areas. The PFS team observed that the
areas of highest concentration of methane overlap with areas where water
vapour and underground water ice are also concentrated. This spatial
correlation between water vapour and methane seems to point to a common
underground source. Further investigations are needed to fully understand
the correlation between (i) presence and distribution of water vapour and
methane in the atmosphere and (ii) the presence of a subsurface ice layer.
--
--------------
Jacques :-)
www.spacepatches.info