Post Launch Support: ASPERA4 instrument on Venus Express

On 4 August 2008 VEX was inserted into a new orbit with a lower perigee. The altitude of the pericentre is now between 185 and 300 km allowing in situ observations of the plasma environment deeper in the ionosphere. This will address questions of atmospheric dynamics, structure, composition and chemistry. Understanding the behaviour of the upper atmosphere will help quantify escape processes to both the solar wind and the surface. These in situ observations will be used as inputs to the PLASLIFE code being developed in Aberystwyth. A key objective of solar system exploration is to understand why the atmospheres of Venus and the Earth have evolved in such radically different manners. ASPERA-4 enables studies the interaction of the solar wind with the upper atmosphere of Venus and hence mass transfer between these systems. To date Venus Express has resulted in multiple special issues of major international journals. The total resources requested consists of 0.5 SY for a PDRA and 0.02 SY for Prof. M. Grande. With FEC and travel comes to a total expenditure of £31,624. This would enable Aberystwyth to develop software to bin the ion data by solar wind conditions, to develop software to use lower altitude ion data and undertake comparisons with VIRA, give input to IRF as required, support science planning and team meetings and to monitor the MCP's on the NPD.