Solar ultraviolet imaging instruments in space pose most demanding requirements on their detectors in terms of dynamic range, low noise, high speed, and high resolution. Yet UV detectors used on missions presently in space have major drawbacks limiting their performance and stability. In view of future solar space missions we have started the development of new imaging array devices based on wide band gap materials (WBGM), for which the expected benefits of the new sensors - primarily visible blindness and radiation hardness - will be highly valuable. Within this initiative, called “Blind to Optical Light Detectors (BOLD)”, we have investigated devices made of AlGa-nitrides and diamond. We present results of the responsivity measurements extending from the visible down to extreme UV wavelengths. We discuss the possible benefits of these new devices and point out ways to build new imaging arrays for future space missions.
Approved in October 2000 by ESA's Science Programme Committee as a flexi-mission, the Solar Orbiter will study the Sun and unexplored regions of the inner heliosphere from a unique orbit that brings the
probe to within 45 solar radii (0.21 AU) of our star, and to solar latitudes as high as 38°. The scientific payload to be carried by the Orbiter will include a sophisticated remote-sensing package, as
well as state-of-the-art in-situ instruments. Given the technical and financial constraints associated with this mission, it is essential that key technologies requiring significant development be identified as early as possible. ESA has therefore set up a Payload Working Group (PWG), made up of members of the scientific community with expertise in instrumentation of the kind envisaged for the Solar Orbiter. The tasks of the PWGs included: 1) a realistic assessment of the strawman payload, including definition of mass, size, power requirements; 2) identification of key problem areas arising as a result of the extreme thermal and radiation environments; 3) identification of necessary technological developments; and 4) provision of detailed input to a Solar Orbiter Payload Definition Document (PDD). This contribution summarizes the activities and findings by the Solar Orbiter Payload Working Group.
Approved in October 2000 by ESA's Science Programme Committee as a flexi-mission and re-confirmed in May 2002 as an element in the new ESA science programme "Cosmic Vision", the Solar Orbiter will study the Sun and unexplored regions of the inner heliosphere from a unique orbit that brings the probe to within 45 solar radii of our star, and to solar latitudes as high as 38 degrees. The scientific payload to be carried by the Solar Orbiter will include both remote-sensing instruments and an in situ package. Launch is currently scheduled for 2012. Given the technical challenges associated with this mission, it is essential that key technologies requiring significant development be identified as early as possible. ESA has therefore set up Payload Working Groups whose task it is to address potential problem areas arising as a result of the extreme thermal and radiation environment and to identify necessary technological developments.
BOLD (Blind to the Optical Light Detectors) is an international initiative dedicated to the development of novel imaging detectors for UV solar observations. It relies on the properties of wide bandgap materials (in particular diamond and Al-Ga-nitrides). The investigation is proposed in view of the Solar Orbiter (S.O.) UV instruments, for which the expected benefits of the new sensors -primarily visible blindness and radiation hardness- will be highly valuable. Despite various advances in the technology of imaging detectors over the last decades, the present UV imagers based on silicon CCDs or microchannel plates exhibit limitations inherent to their actual material and technology. Yet, the utmost spatial resolution, fast temporal cadence, sensitivity, and photometric accuracy will be decisive for the forthcoming solar space missions. The advent of imagers based on wide-bandgap materials will permit new observations and, by simplifying their design, cheaper instruments. As for the Solar Orbiter, the aspiration for wide-bandgap material (WBGM) based UV detectors is still more sensible because the spacecraft will approach the Sun where the heat and the radiation fluxes are high. We describe the motivations, and present the program to achieve revolutionary flight cameras within the Solar Orbiter schedule as well as relevant UV measurements.
The key mission objective of the Solar Orbiter is to study the Sun from close-up (45 solar radii, or 0.21 AU) in an orbit tuned to solar rotation in order to examine the solar surface and the space above from a co-rotating vantage point at high spatial resolution. Solar Orbiter will also provide images of the Sun's polar regions from heliographic latitudes as high as 38 degrees. The strawman payload encompasses two instrument packages: Solar remote-sensing instruments: EUV full-sun and high resolution imager, high-resolution EUV spectrometer, high-resolution and full-sun visible light telescope and magnetograph, EUV and visible-light coronagraphs, radiometers. Heliospheric instruments: solar wind analyzer, radio and plasma wave analyzer, magnetometer, energetic particle detectors, interplanetary dust detector, neutral particle detector, solar neutron detector. To reach its novel orbit, Solar Orbiter will make use of low-thrust solar electric propulsion (SEP) interleaved by Earth and Venus gravity assists. Solar Orbiter was selected by ESA's Science Programme Committee (SPC) in October 2000 as a Flexi-mission, to be implemented after the BepiColombo cornerstone mission to Mercury before 2013. This paper summarizes the science to be addressed with the Solar Orbiter, followed by brief descriptions of the strawman payload, the mission profile, and the spacecraft and ground segment designs.
Conference Committee Involvement (2)
Solar Physics and Space Weather Instrumentation
31 July 2005 | San Diego, California, United States
Telescopes and Instrumentation for Solar Astrophysics
7 August 2003 | San Diego, California, United States