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Space Dosimetry
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Jarvis A. Caffrey, David M. Hamby
The RAD (Figure 74.2), built by Southwest Research Institute, represents the latest implementation of telescope spectrometers. It is currently operating onboard the Mars Science Laboratory (MSL) Curiosity rover to measure the flux profile at the Mars surface in support of future human exploration and Martian life investigations. The RAD is also slated to replace the IV-CPDS as an operational area monitor inside the ISS by 2015. The MSL RAD houses three silicon diodes as a charged particle telescope, each segmented into several complex regions that provide position dependence sufficient to minimize path length uncertainty. Three scintillators housed beneath the diode stack measure energy deposition from charged particles arriving through the telescope and also perform spectroscopy for neutrons and photons arriving from all angles. The thallium-doped cesium iodide (CsI(Tl)) scintillator sits directly below the telescope and is shaped to match its field of view for charged particle collection. It also responds well to photons and, to some degree, neutrons from all directions. An organic plastic scintillator constructed of Bicron BC-432 m sits below the CsI(Tl) crystal, primarily intended for neutron detection by recoil proton production, but also sensitive in some degree to photons. A BC-432 m anticoincidence shield surrounds the inner scintillators to eliminate charged particle background, except for those traversing the telescope counted for spectroscopy or particle identification. Photodiodes, nearly identical to the diodes used in the telescope, are bonded to the scintillators for light measurement, thus requiring only a single power supply for the entire system [101]. Neutron and gamma contributions are separated in the central scintillators by evaluating the unique response of each scintillator with a statistical maximum-likelihood inversion technique developed for that purpose [102]. Other independent neutron detectors are described in the following section.
Autonomous robots for harsh environments: a holistic overview of current solutions and ongoing challenges
Published in Systems Science & Control Engineering, 2018
Cuebong Wong, Erfu Yang, Xiu-Tian Yan, Dongbing Gu
A number of planetary robots have been deployed to Mars with notable success. These systems are tasked with objectives such as sampling local soil and rocks, mapping the environment, capturing images of key landmarks, and monitoring local environment conditions. The Curiosity rover system is the most current rover in operation on Mars, possessing a number of notable features to enable it to traverse the challenging Martian terrain. Its rocker-bogie suspension system consists of six wheels purposely arranged to enable a rocking motion between the front and back wheels. This design provides the platform with greater flexibility to traverse through uneven surfaces (Grotzinger et al., 2012).