VENUS EXPRESS PLS SUPPORT

点击翻译按钮获取中文摘要

The Venus Express mission proposal was organised by Prof. Taylor from the UK and two colleagues from France and Germany respectively. He continues to implement the goals of the project at several levels, now principally in the role of Interdisciplinary Scientist (IDS), but also by continuing to support the development of the mission in a broader sense by assisting the Project Scientist and the ESA team. The overall mission aim is a global investigation of the Venusian atmosphere, plasma environment and some aspects of the surface. The IDS project is focused on understanding the atmosphere of Venus, in particular the key processes that determine the climate at the surface, its evolution, and similarities and differences with the Earth. Venus Express is ESA's first mission to Venus, based on re-use of the Mars Express spacecraft. It has a payload consisting of seven scientific instruments, ASPERA, PFS, SPICAV/SOIR, VeRA and VIRTIS, with heritage from Mars Express and Rosetta, and MAG and VMC, which are new instruments. VIRTIS (Visible-Infrared Thermal Imaging Spectrometer) is the largest instrument, and has two Oxford Co-Is, Prof. Taylor and Dr P. Irwin. Venus Express was successfully launched in late 2005, arriving at Venus at the beginning of April 2006. The mission then completed a nominal mission of 500 Earth days (2 Venus days), and is now well into its first mission extension, due to end in May 2009. However, the spacecraft still has enough fuel to maintain its orbit for several years, so ESA is currently planning a second mission extension covering operations for a further two years (until May 2011) and this is considered very likely to go ahead. During the extended mission Venus Express will focus on several new science goals. - Mapping of long-term and interannual variation of atmospheric behaviour. Many of the meteorological and climatological process being observed show secular variations or long-term periodicity that can only be resolved with a long run of data. There is also some evidence showing a marked decrease of SO2, which could indicate episodic volcanic activity. - Mapping of as-yet-unexplored regions of the surface. The VIRTIS instrument is generating maps of surface properties using nightside observations in infrared window regions - however, only ~ 70% of the surface has been mapped to date. - Venus Express arrived at Venus near the solar minimum; to fully calculate the escape budgets we need measurements of solar wind interaction not only at solar minimum but through to solar maximum as well (due to occur around 2012). - Atmospheric drag experiments to investigate density variations in the upper atmosphere. - Joint observations between Venus Express and the Japanese Venus Climate Orbiter, which will arrive at Venus in December 2010. All of these activities are related to the applicant's IDS role and will require careful planning and negotiation of spacecraft operations and instrument modes and sequences, ideally including with the Japanese scientists and mission managers, as described later. ESA has discussed a joint working group with the Japanese agency in order to take this forward and the applicant has been invited to be a member of this. Meanwhile, the key collaborations related to implementing the successful IDS proposal are with the principal investigator groups for the various instruments, and with other IDSs at University of Nantes, Astrobiology Division of the Nature and Science Museum in Denver, and the California Institute of Technology. The collaborations mentioned above contribute expertise on exospheric processes, interior processes, and surface chemistry to the studies of climate. The role at Oxford is focussed on the Venusian atmosphere, including the use of the remote sensing instruments on the payload to investigate the temperature, composition and deep cloud structure on Venus, and to understand the global circulation, cloud chemistry and meteorology.