Saturn's three-dimensional magnetosphere:Prof Andrew Coates & Dr Geraint Jones

Cassini has recently begun its Solstice mission at the beginning of its seventh year at Saturn. With the data already gathered, there is significant information about the three dimensional magnetosphere, including high latitude passes and about 75% sampling in local time. In the next few years, the gaps in local time sampling will be filled in, and further high latitude orbits will be made. This project will concentrate on the three dimensional structure of Saturn's magnetosphere, including an analysis of the shape of the boundaries and cusp regions within the magnetosphere. This will use data from the MSSL's Electron Spectrometer (part of CAPS), as well as data from other on-board instruments. In addition, during the high latitude passes, the electrons that drive Saturn's aurora and radio emissions will be studied. 

Courtesy MIMI team; from Young & Coates, Space Research Today, in press, 2010


Titan and its plasma interaction: Prof Andrew Coates & Dr Geraint Jones)

fig3.pngSaturn's largest moon has already given a wealth of surprises from the plasma data. These include heavy negative ions at low altitudes in Titan's ionosphere, the source of aerosols, and ionospheric photoelectrons seen at large distances from Titan. Data from over 70 flybys are already available, with more than another 50 to come in the next 3 years. Titan is usually in Saturn's magnetosphere, but occasionally (twice so far) in the magnetosheath. This project will be an investigation of the variability of Titan's plasma interaction with upstream plasma conditions, and will involve data analysis and comparison with models. Also, further work is needed on the negative ions in the ionosphere, particularly during low altitude flybys.

 

 

 

 

(Left) from Coates et al., Faraday Discussions, in press, 2010.

(Right) from Coates, 2009

 


Venus magnetosheath: Prof Andrew Coates & Dr Geraint Jones

Venus differs from Earth in several ways – including the lack of a magnetic field. In this project we will examine the interaction of Venus with the solar wind. A bow shock forms upstream as the solar wind flow is supersonic, but the obstacle in this case is the Venus ionosphere. Behind the bow shock is the magnetosheath, which plays a key role in solar wind coupling to Venus. While there are some similarities to magnetosheath regions at Earth and Saturn, there are differences too. We will examine electron data from Venus Express in the magnetosheath, particularly the electron distribution function and properties of waves.

 

(Left) From Coates et al., Planet. Space Sci., in press, 2010.

 


Mars atmosphere modeling: Prof Andrew Coates & Dr Andrew Griffiths

In 2018 the ExoMars rover is planned to land on Mars. The MSSL-led PanCam instrument on board includes filters to study the amount of water vapour in the atmosphere. In this project, we will develop algorithms for analysing the intensity of the Sun at different wavelengths measured from the surface. Tha aim is to prepare analysis techniques for the mission itself, eventually giving water vapour content in the Martian atmosphere as a function of height.

ExoMars2010.JPG

Courtesy ESA


Icy Moon interaction investigations using Cassini data: Dr. Geraint Jones

Most of Saturn's many icy moons reside inside Saturn's magnetosphere, where they are bombarded by energetic electrons and ions confined by Saturn's magnetic field. Using data from the Cassini Plasma Spectrometer and other instruments aboard the Cassini spacecraft, the interactions between these moons and the magnetosphere can be investigated. The moons carve out almost empty regions within the magnetosphere called microsignatures, and release neutral gas and ions into the magnetosphere. In return, the moons' surfaces are altered by the energetic bombardment, causing subtle colour and brightness differences that aren't yet fully understood. Close flybys of these moons, many of which will happen before the end of the mission in 2017, will provide valuable information on these processes. Of particular interest is the set of complex interactions taking place at Enceladus - a 500km-wide moon spewing water ice and vapour into the magnetosphere. The CAPS instrument has directly detected negative ions and tiny, charged icy grains as Cassini has swept close to this moon. The project would aim to better-understand moon-magnetosphere interactions with the possibility of applying new knowledge to other contexts such as Jupiter's moons.

PIA12733.tif

 

 

Mimicking planetary environments for assessing the survivability of bacterial organisms within an artificial environmental chamber. A combined planetary atmosphere and microbiological study for exploring panspermia.: Prof. Peter Muller and Prof. John Ward

 

There is now detailed knowledge of the conditions in the atmosphere and at the surface of several planets and moons in the solar system. The surface of Mars, the atmosphere and surface of Venus and the atmosphere and surface of Titan have been described in some detail over the last few years. In parallel with this, on Earth the microbial ecology of extreme environments have been continuing at a great pace and almost all habitats on Earth have diverse microbial colonisation. It is now pertinent to ask questions as to whether the extra-terrestrial environments on these other planets and moons could support life in the form of bacteria. For example, although planetary protection continues to be taken very seriously for extra-terrestrial spacecraft it is unknown whether terrestrial organisms could survive in the vacuum of interplanetary travel and landing on another planetary surface. An environmental chamber has been developed at MSSL for testing the Panoramic Camera in Martian conditions. This can simulate the pressure and temperature conditions and be run in a hands off automated fashion. With a small addition, other gases could be introduced into the chamber (Nitrogen is currently employed) to represent the atmospheric conditions. Such a chamber has been proposed for the CIF Origins spend in 2009/2010 and the student would be heavily involved in its commissioning at MSSL and establishment in Prof. Ward's laboratory.

We propose to use this environmental chamber to simulate the atmospheres of

Venus; Mars; and Titan and assess the survivability of terrestrial bacteria in the chamber. Long term studies of several months will be used and the chamber inoculated with single or multiple species of known bacteria or with complex mixtures. The analysis of growth within the chamber will use molecular techniques to assess the diversity (when mixtures are inoculated) and numbers of bacterial through time (16s rDNA and QPCR analysis respectively) The gases within the chamber will also be monitored through time to assess changes made by the growth and respiration of the added bacteria. Model land surface or liquid surfaces will also be used within the chambers to mimic the surface or subsurface of Titan lakes or sub-surface liquid water on Europa. The environmental chamber has been developed at MSSL and will be fitted with monitoring probes for pressure, temperature, gas composition and with a UV laser light source for monitoring fluorescence (Storrie-Lombardi et al 2008). The chamber will be housed in the Structural and Molecular Biology Department, Darwin Building,

UCL, where we have extensive microbial growth and handling facilities and expertise. We have carried out radiation studies on Antarctic bacteria using conditions defined by a radiation model we have developed (Dartnell et al, 2007a and 2007b) based on from Geant4.