GENERAL SCIENTIFIC SUPPORT
Staff of the Space Science Department are often requested to provide scientific advice within ESA, and to participate in committees or working groups that concern matters outside the purview of the Scientific Directorate and of ESA. Some of the major assignments of this type are described in this section.
Continued support was given to the definition and follow-up of the Agency's Technology Research Programme (TRP) and the General Support Technology Programme (GSTP): A. Peacock, G. Schwehm (until mid-1996) and Y. Jafry (thereafter) were members of the Steering Group for TRP Theme 4 'Deep Space and Observatory Facilities'.
In addition, staff provided scientific support to individual TRP and GSTP projects in the Technical Directorate. Thus, H. Svedhem of the Solar System Division has given advice to two TRP studies in the field of surface-penetrating radars. One study, managed by the Radio Frequency Systems Division, concerns instrument definition and breadboarding of a planetary radar to probe the subsurface of planets to depths of several km. A possible application is the characterisation of the polar permafrost on Mars in order to estimate the global water abundance. The second study, managed by the Automation & Ground Facilities Division, concerns the definition and bread-boarding of an autonomous navigation radar for a Lunar/Martian rover. This involvement aims to ensure, at an early stage, that the scientific benefits of this engineering instrument will be exploited and, if feasible, expanded.
A. Chicarro provided scientific support to several TRP studies (Mars Environment Model, Mobile Instrument Deployment Device, Micro-Robots for Scientific Applications), in particular as a member of the Tender Evaluation Board. He also provided scientific advice to technical studies such as Rover Navigation Radar, Locomotion Concepts, Analysis for Moon Exploration, and Moon Missions Russian Experience.
Staff from the Astrophysics Division gave scientific and technical advice to numerous studies concerning the development and test of advanced filters for extreme-UV and soft X-ray spectroscopy, hard X-ray solid state detectors and GaAs solid state imaging detectors, and on the development of microchannel plate optics for X-ray astrophysics, IR suppression filters for optical astronomy, and low-noise preamplifiers. Staff also supported the development of holographic gratings and cryogenic filters.
In some cases, SSD also performed the calibration and characterisation of items developed under TRP/GSTP, commensurate with its expertise and laboratory capability.
The detailed evaluation of the technical and scientific performance of some of the above items led to scientific research publications in collaboration with industry.
A. Chicarro, R. Grard and B.H. Foing provided scientific support to two lunar studies conducted in the Agency in parallel with the Science Directorate's MORO Phase A study (see 3.3.2.2). These were LEDA (Lunar European Development Approach) and ELSPEX (European Lunar South Pole Expedition).
P. Bely of the Space Telescope Science Institute (STScI) completed the final report of the ESA Space Interferometry Study Team on the comparison of free-flying and lunar-based versions for a kilometric baseline array. The study was published in ESA report SCI(96)7 of June 1996. He also participated in the team studying the scientific justification and feasibility of a Very Low Frequency Array on the far side of the Moon.
During 1995, the possibility of proposing and developing a new European instrument to be mounted on the Hubble Space Telescope during the Maintenance & Refurbishment mission in 2002 was investigated. Staff of the Astrophysics Division at ESTEC (notably P. Jakobsen) and the Space Telescope-European Coordinating Facility (ST-ECF; notably R. Fosbury) were involved in a preliminary study of three possible instrument concepts: a fully multiplexed 3D spectrograph for the near-IR; a coronographic instrument; and an instrument based on superconducting tunnel junction (STJ) detectors - finally the preferred choice. The study results and the scientific case were presented in a special issue of the ST-ECF Newsletter, No. 23. An engineering feasibility study was then undertaken on the STJ- based instrument. However, increasing difficulties in the budget of the ESA Science Programme forced ESA to reconsider the situation and, as a consequence, there will not be an ESA AO for an HST instrument for 2002. The possibility of SSD proposing participation in an STJ-based instrument in response to a NASA AO remained under consideration.
Staff at the STScI (notably P. Bely, M. Stiavelli, S. Casertano, C. Skinner and C. Burrows) and the ST-ECF contributed to the initial studies to define the characteristics of NASA's Next Generation Space Telescope (NGST), a planned near-IR space- based telescope. Although the details differed considerably, the studies agreed in the final conclusion that a space-based telescope with the required characteristics is feasible within reasonable time and budget constraints. As an example, the configuration suggested by the Goddard study is an 8 m diameter deployable mirror with a large sunshield, placed in a halo orbit near the Earth-Sun Lagrangian L2 point. Passive cooling will keep the optics and the instrument bay at around 40 K; active cooling is required only for the long-wavelength detectors operating beyond 8 µm. The instruments consist of wide-field imagers and spectrometers covering 0.6-20 µm.
In the area of space debris, G. Schwehm continued to provide support to the ESA Space Debris Advisory Group. He was a member of the joint German-Russian Study Group on Advanced Interplanetary Missions using Nuclear Electric Propulsion. He was also a member of an ad hoc Advisory Group to provide expert advice to DARA on programmatic and technical issues concerning the scan platform for Mars-96.
The Institute of Space and Astronautical Science (ISAS) of Japan, through ESA, has invited participation of European scientists in the ASCA X-ray astronomy programme in order to maximise the scientific return of the mission. ASCA is the first X-ray imaging mission operating at 0.5-12 keV. It observes typically one or two sources per day. Some 10% of the total observing time is allocated to proposals from ESA member states. The over-subscription factor from the last call for proposals was approximately 3.7. Staff from the Astrophysics Division (notably A.N. Parmar) are involved in proposal handling, screening and technical evaluation as well as providing support to the European Time Allocation Committee appointed by ESA.
During the past 5 years, W. Wamsteker of the IUE Observatory has actively supported - in collaboration with the International Affairs Office of ESA - the United Nations Outer Space Office with the implementation of the recommendations of the Committee for the Peaceful Use of Outer Space (COPUOS), to stimulate and develop the basic space sciences in developing countries. These efforts have borne fruit in various ways, such as the installation of a small telescope facility in Sri Lanka, three Space Science Summer Schools under a Regional Central American Association of Astronomy, the signature of a collaboration agreement between the major observatories in Egypt and Israel, and the distribution, via the United Nations, of computing equipment to universities without such facilities.
Finally, it should be mentioned that SSD staff are active in numerous scientific societies and some of the Scientific Unions (COSPAR, IAU, URSI), where they contribute to scientific meetings by organising special sessions and discussions and, in some cases, hold elective offices. In several instances, staff were also appointed jury members for Ph.D. theses. Some staff also teach space sciences at Member State universities, notably V. Domingo (in Barcelona), M.C.E. Huber (at ETH Zürich), R. Schmidt (in Graz), A. Pedersen (in Oslo) and M.A.C. Perryman (in Leiden). The direct contact between ESA staff and students and staff at the universities concerned continues to be mutually rewarding.
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