TY - JOUR
T1 - Life after Venus Express: Science goals for a European Venus radar orbiter
AU - Wilson, Colin F.
AU - Ghail, Richard
PY - 2014/8/2
Y1 - 2014/8/2
N2 - ESA’s Venus Express mission has led to a renaissance of Venus
science, following a dearth of Venus missions in the previous 15 years.
Venus Express has made many discoveries in atmospheric science, for
which its payload was optimised; however it has also provided
tantalising hints about the geological activity of the planet.
Mesospheric sulphur dioxide abundances vary by 1000% on decadal
timescales, in a pattern which suggests episodic volcanic injections
[Marcq et al. Nature Geosci 2013; Esposito, Science 1984]; anomalous
emissivity near suggest volcanic hotspots implies geologically recent,
as-yet-unweathered lava flows [Smrekar et al., Science 2010]; and recent
results, if confirmed, show temporal evolution of thermal emission from
some regions of the surface may be direct evidence of volcanic activity
during the duration of the VEx mission [Shalygin et al., LPSC 2014].
While there are more results to be obtained yet from the Venus Express
dataset, further investigation of these phenomena will require a new
Venus mission. We therefore propose an orbiter mission focussed on
characterising the geological activity of Venus. The key instrument
would be a Synthetic Aperture Radar (SAR). Why a radar mission following
NASA’s Magellan mission? Radar capabilities are vastly improved in
the last 30 years and a modern radar would be capable of spatial
resolution approaching two orders of magnitude better than that from
Magellan; this enables a wide range of investigations, from detailed
study of tectonic, volcanic and Aeolian features, to stratigraphy for
better reconstruction of geological epochs. Interferometric SAR could
also be used to study the centimetre-scale surface deformations due to
current volcanic or tectonic activity. Constraints on interior structure
can be obtained not only from improved gravity mapping (from spacecraft
tracking) but also by studying the spin state of Venus from
high-resolution radar measurements. The radar measurements will be
complemented by a further suite of instruments which may include a
dedicated surface emission mapper using near-infrared spectral windows;
a spectrometer suite to map sulphur dioxide and other possibly volcanic
gases; and possibly a subsurface sounding radar to reveal the structure
of lava flows and other surface structures. This mission, following on
from the 2007 EVE [Chassefière et al., Exp. Astron 2009] and 2010
Envision [Ghail et al., Exp. Astron 2012] proposals, is being developed
for proposal to ESA as a “Medium-class” mission in late
2014.
AB - ESA’s Venus Express mission has led to a renaissance of Venus
science, following a dearth of Venus missions in the previous 15 years.
Venus Express has made many discoveries in atmospheric science, for
which its payload was optimised; however it has also provided
tantalising hints about the geological activity of the planet.
Mesospheric sulphur dioxide abundances vary by 1000% on decadal
timescales, in a pattern which suggests episodic volcanic injections
[Marcq et al. Nature Geosci 2013; Esposito, Science 1984]; anomalous
emissivity near suggest volcanic hotspots implies geologically recent,
as-yet-unweathered lava flows [Smrekar et al., Science 2010]; and recent
results, if confirmed, show temporal evolution of thermal emission from
some regions of the surface may be direct evidence of volcanic activity
during the duration of the VEx mission [Shalygin et al., LPSC 2014].
While there are more results to be obtained yet from the Venus Express
dataset, further investigation of these phenomena will require a new
Venus mission. We therefore propose an orbiter mission focussed on
characterising the geological activity of Venus. The key instrument
would be a Synthetic Aperture Radar (SAR). Why a radar mission following
NASA’s Magellan mission? Radar capabilities are vastly improved in
the last 30 years and a modern radar would be capable of spatial
resolution approaching two orders of magnitude better than that from
Magellan; this enables a wide range of investigations, from detailed
study of tectonic, volcanic and Aeolian features, to stratigraphy for
better reconstruction of geological epochs. Interferometric SAR could
also be used to study the centimetre-scale surface deformations due to
current volcanic or tectonic activity. Constraints on interior structure
can be obtained not only from improved gravity mapping (from spacecraft
tracking) but also by studying the spin state of Venus from
high-resolution radar measurements. The radar measurements will be
complemented by a further suite of instruments which may include a
dedicated surface emission mapper using near-infrared spectral windows;
a spectrometer suite to map sulphur dioxide and other possibly volcanic
gases; and possibly a subsurface sounding radar to reveal the structure
of lava flows and other surface structures. This mission, following on
from the 2007 EVE [Chassefière et al., Exp. Astron 2009] and 2010
Envision [Ghail et al., Exp. Astron 2012] proposals, is being developed
for proposal to ESA as a “Medium-class” mission in late
2014.
M3 - Article
VL - 40
JO - 40th COSPAR Scientific Assembly. Held 2-10 August 2014, in Moscow, Russia
JF - 40th COSPAR Scientific Assembly. Held 2-10 August 2014, in Moscow, Russia
ER -