SRON_Spectrum_2016

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16 SRON Spectrum For the characterization of aerosols it is important that a satellite instrument measures both the intensity and polarization of the light reflected by the earth’s atmosphere. Up until now only one such instrument has been launched: the French POLDER instrument onboard the PARASOL satellite. Its successor, the 3MI instrument of ESA on the MetOp-SG satellite, is a similar measurement instrument that is expected to be operational from 2021 onwards. The aerosol measurements from these being developed by the NASA Goddard Space Flight Center, and a polarimeter. Due to its technical and scientific specifications SPEX is NASA’s preferred choice for a polarimeter. The two measurement instruments complement each other: measurements from the polari - meter help to correct ocean measurements and the OCI instrument measures certain properties of clouds and aerosols. Together these instruments will provide data that are important for multidisciplinary satellite missions will mainly provide information about the quantity climate research. “There are many and size of the particles but will not reveal enough about the extent different types of to which the particles absorb or reflect light and almost nothing about If efforts to obtain sufficient national aerosol particles and their chemical composition. funding are successful then NASA their interactions will definitely select SPEX for PACE. A major step forward in aerosol research requires a new instrument that is far more accurate. SRON already has a prototype for that in - with the climate are complex“ SRON would then become responsible for the construction of the instrument strument: SPEX. Otto Hasekamp, Principal Investigator for the SPEX instrument: “Thanks to an entirely new measurement principle, SPEX mea sures more accurately than its predecessors by more than a factor of ten. Therefore with SPEX we can determine the extent to which aerosols absorb and scatter light. We can also determine the chemical composition of aerosols. For example, the instrument will help us to distinguish sea salt from harmful soot.” and the processing of the data. Together with Dutch parties, SRON would then ensure the integration of the different subsystems and also carry out the various tests. Furthermore, SRON will produce part of the flight electronics, will perform the calibration, and will deliver the associated software. After the launch, SRON scientists will derive aerosol properties from the spectro-polarimeter data. The importance of SPEX for NASA is ap - parent from the major contribution The technology behind SPEX has already been successfully used for local groundbased that NASA wants to make to the SPEX instrument. aerosol measurements at the Dutch atmospheric measurement mast in Cabauw (the CESAR Observatory). Better climate predictions The measurement results from The SPEX technology was also used in PACE/SPEX will help climate researchers to gain a better under- Sea salt, dust, and volcanic ash are aerosols Leiden University’s citizen science project from natural sources (Katherine Mann). iSPEX, which won the Academische jaarprijs in 2012. Furthermore, SRON has constructed an airborne version of the SPEX instrument prototype for a flight under the NASA research aircraft ER-2, which performs measurements at an altitude of 21 kilometers. This instrument, called SPEX Airborne, first flew in February 2016. standing of the role of aerosols in the earth’s climate and to quantify this. That will lead to better climate predictions, which in turn will help to determine the climate policy. For example, the results could contribute to a report from the Intergovernmental Panel on Climate Change (IPCC), which is published once every five to six years. In addition, with the arrival of PACE/SPEX, scientists PACE mission As SPEX is so accurate, NASA would like the instrument to fly onboard its climate satellite PACE (Pre-Aerosols, Clouds and ocean Ecosystems), will be able to accurately determine the origin of air pollution. This information is extremely valuable for government bodies when they take measures to improve air quality. the launch of which is planned for 2022. The PACE satellite will have two instruments onboard: the Ocean Color Instrument (OCI), which is EVELINE VAN DER LINDEN
THE EXPERTISE TRIANGLE / SPACE INSTRUMENTS SPEX airborne ready for scientific flights The SPEX technology has been designed to investigate aerosols (small particles) in the atmosphere from space. A prototype – SPEX airborne – has been converted to fly onboard a NASA research plane at an altitude of 21 kilometers. A team of SRON engineers has assembled this instrument over the past months and prepared it for the harsh conditions found at that altitude. SPEX airborne has successfully completed more than five flight hours. 17 SRON Spectrum The ER-2, the NASA research plane that carries SPEX airborne (NASA). EEach component looks the part. All of the components have been manufactured from aluminum and have a golden glow. Bolts have been placed with surgical precision at perfectly regular distance from each other. It is clear that the instrument has been produced by specia l - ists. SPEX airborne is ready for its first flight in Palmdale, Cali for nia. The SPEX instrument will be installed in the wing compartment of a NASA research plane (the ER-2). The instrument has been thoroughly tested over the past few months. In addition, SPEX airborne has successfully completed an extensive set of electrical tests. Extreme conditions At an altitude of 21 km it is just as cold as in the Antarctic winter and the pressure there is comparable with that of a vacuum. Via observation holes, SPEX airborne is in “At an altitude of 21 km direct contact with this outside air, as a window would it is just as cold as in the Antarctic winter and disrupt the incoming light. the pressure there is The instrument must therefore be able to carry out comparable with that measurements under these of a vacuum” conditions. Many standard electronic components are not suitable for this due to problems with the dissipation of heat as result of which electronics can burn out. SRON researchers therefore designed and built special components and systems, or purchased these. For the required accuracy of SPEX airborne it is vitally important that the optical system – the heart of SPEX airborne – does not vary in temperature too much. Heating elements ensure that the optics of SPEX and the associated camera remain at room temperature with a deviation of less than 0.1 °C even though the outside temperature is -55°C. T H E E X P E R T I S E T R I A N G L E SRON develops, builds and uses instruments that enable scientific breakthroughs in space research. This section in the Spectrum newsletter features a different aspect of SRON’s expertise triangle each time: ▶ Science covers astrophysical and atmospheric research and spectroscopy. ▶ Enabling Technology develops detectors, readout electronics, micro- mechanical systems in very cold conditions, lithography facilities, and cleanrooms. ▶ Space Instruments concerns the system knowledge and the design, development, construction, and approval of flight instrumentation in international consortia.
Page 1 and 2: SPECTRUM NO. 18 MARCH 2016 DISTANT
Page 3 and 4: S H O R T N E W S sun. The sunlight
Page 5 and 6: More collaboration with China In th
Page 7 and 8: or star, space-time is curved. As a
Page 9 and 10: Nevertheless, there are several fac
Page 11 and 12: indicate that a planet is moving in
Page 13 and 14: ters of galaxies, and how do black
Page 15: Photo: NASA. In our atmosphere minu
Page 19 and 20: low, or a component in the system t
Page 21 and 22: 2 November 2015, Los Angeles: How i
Page 23 and 24: shoe size Pipo de Clown. Air insula
Page 25 and 26: can only take a glimpse inside thro
Page 27 and 28: uilt in a year before I was even bo
Page 29 and 30: Mission SRON contribution Studies m
Page 31 and 32: 31 SRON Spectrum Mission facts > Un

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