We report on the current Venus Emissivity Mapper (VEM) instrument design and development status onboard NASAs Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy (VERITAS) and ESAs EnVision orbiters. The VEM instrument is a push broom multispectral imager that comprises an optical system based on a sophisticated filter assembly with 14 spectral bands and an InGaAs detector with integrated thermoelectric cooler. A turn window mechanism and a two-staged baffle in front of the optics protect the instrument against contamination and straylight. The instruments nominal mass is approximately 6 kg. VEM opens the path for mapping Venus surface emission with a global coverage of >70%.
The first NASA spacecraft to visit and explore planet Venus since the 1990s will be the Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy mission (VERITAS) orbiter. The Venus Emissivity Mapper (VEM) onboard the spacecraft is designed for surface mapping of Venus within dedicated atmospheric spectral windows. The instrument will provide global coverage for the detection of thermal emissions like volcanic activity, surface rock composition, water abundance, cloud formation and their dynamics by observing 14 narrow filter bands in the near-infrared to short-wave infrared (NIR, SWIR) range of 790 nm to 1510 nm. An almost identical instrument will be part of ESA's recently announced EnVision mission to Venus, the VenSpec-M in the Venus Spectroscopy Suite (VenSpec). The utilized photodetector for both missions will be an InGaAs type imaging sensor with integrated thermoelectric (TE) cooling, comprising a 640x512 pixel array with 20 mu m pixel pitch. In general, a space environmental qualification of electronic devices combines its susceptibility to radiation induced single event effects (SEE) and the evaluation of permanent degradation effects due to total ionizing dose (TID) and displacement damage dose (DDD). Following a successful qualification test with heavy-ions focusing on SEE, our imaging sensor was subject to a proton irradiation test campaign at Helmholtz-Zentrum Berlin (HZB) for combined TID and DDD testing. To track the sensor evolution, we subdivided the proton fluence into 10 irradiation steps with intermediate measurements. The collected data provide information on the evolution of dark current, light sensitivity and pixels showing random-telegraph-noise (RTN) on the sensor during a 5-year mission.
The scientific goals of the PLATO mission are to search for planetary transits across a large number of stars. We describe its end-to-end data processing architecture, including the infrastructure to configure the instrument consisting of 26 cameras and 14 data-processing units, the on-board data acquisition, processing and storage, and the ground processing pipeline. In the case of PLATO, only the combination of onboard and on-ground data processing makes it possible to achieve the ambitious goals.
The Venus Emissivity Mapper (VEM) as part of NASAs Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy mission (VERITAS) is designed for mapping the surface of Venus within dedicated atmospheric spectral windows. The instrument will provide global coverage for detection of thermal emissions like volcanic activity, surface rock composition, water abundance and cloud formation as well as dynamics by observing 15 narrow filter bands in the near infrared to short wavelength infrared (NIR, SWIR) range of 862 nm to 1510 nm. An almost identical instrument will be part of ESAs EnVision mission to Venus, the VenSpec-M in the Venus Spectroscopy Suite (VenSpec). The utilized photodetector is an InGaAs type imaging sensor with integrated thermoelectric (TE) cooling. It comprises a 640x512 pixel array with 20 μm pixel pitch. Following the mission requirements we irradiated the detector with a set of ions of various stopping powers and range distributions from lower energy Argon (Ar) to higher energy Xenon (Xe). Therefore, exploiting the mentioned ions and proper tilt angles during irradiation, our data covers a Linear Energy Transfer (LET) range of 7 to 75 MeVcm2/mg which fulfills NASA/JPL led space qualification standards (up to 75 MeVcm2/mg) as well as ESA space qualification standards (up to 60 MeVcm2/mg) for heavy-ion irradiation. Our electrical setup consists of a dedicated over-current protection detecting high-current states occurring during irradiation steps and immediate power cycling to prevent physical damage of the device. From the event rates seen during the test we calculated the specific cross-sections and therefore can estimate the expected event rates at Venus during the mission. The detector showed saturated cross-sections below 1E-3 cm2 at 10°C with acceptable event rates for the highest LETs and our applications.
Introduction. Understanding the origin and evolution of Phobos and Deimos is the goal of the coming Martian Moons eXploration mission (MMX) led by JAXA [1, 2, 3]. This mission will be launched in 2024 to the Martian system and return samples from Phobos. Before sample return operations, a rover of 25 kg approximately will be delivered to the surface carrying four instruments: a Raman spectrometer (RAX), a radiometer (miniRad), a stereo pair of cameras looking forwards (NavCams), and two cameras looking at the wheel-surface interface, (WheelCams) [4]. The RAX instrument. The RAman spectrometer for MMX, RAX, has been developed together by DLR, INTA/UVA, and JAXA/UTo [5]. It consists of three elements: I) The RAX Laser Assembly (RLA), which was originally designed for the RLS instrument of the ExoMars mission, and includes a laser emitting at 532 nm; II) The RAX Spectrometer Module (RSM), comprising a sophisticated confocal optical assembly and a CMOS detector that covers a spectral range of up to 4000 cm-1 with a spectral resolution of ̴ 10 cm-1; III) The Autofocus System (AFS) to measure with high precision at different positions onto the ground. RAX will in situ examine the minerals of the surface and their formation conditions at rover sampling spots. By analysing the vibrational modes of the substances, RAX will be capable to characterize the igneous phases, volatiles, organic species, and secondary alteration minerals at grain scale. RAX’s targets may be correlated, on the one hand to the orbital data to better approach the spatial distribution and stratigraphic relationship between the Phobos’ blue and red material units, and on the other hand to the mineral and rock types observed on the Mars’ surface by other Raman spectrometers to link their genesis (or not) (e.g. RLS [6], or Supercam [7]). The identified mineral assemblages can be used to determine whether Phobos is a captured asteroid rich in carbon and water, or is a remnant body of a giant impact to Mars. In addition, the information may also support the sample return selection and provide context information of the materials once they are in terrestrial laboratories. References. [1] T. Usui, et al., Space Sci. Rev. 216:49, 2020; [2] S. L. Murchie, D. T. Britt, C. M. Pieters., Space Science 102, 2014, 176–182; [3] C.M. Pieters, S. L. Murchie, N. Thomas, and D. Britt, Planetary and Space Science 102, 2014, 144-151; [4] P. Michel, et al., Earth, Planets and Space 74: 2, 2022; [5] Y. Cho et al., Earth, Planets and Space 73:232, 2021; [6] F. Rull et al., Astrobiology 17 (6-7), 2017, 627–654; [7] S. Maurice et al., Space Sci. Rev. 217, 2021.
Mineralogy is the key to understanding the origin of Phobos and its position in the evolution of the Solar System. In situ Raman spectroscopy on Phobos is an important tool to achieve the scientific objectives of the Martian Moons eXploration (MMX) mission, and maximize the scientific merit of the sample return by characterizing the mineral composition and heterogeneity of the surface of Phobos. Conducting in situ Raman spectroscopy in the harsh environment of Phobos requires a very sensitive, compact, lightweight, and robust instrument that can be carried by the compact MMX rover. In this context, the Raman spectrometer for MMX (i.e., RAX) is currently under development via international collaboration between teams from Japan, Germany, and Spain. To demonstrate the capability of a compact Raman system such as RAX, we built an instrument that reproduces the optical performance of the flight model using commercial off-the-shelf parts. Using this performance model, we measured mineral samples relevant to Phobos and Mars, such as anhydrous silicates, carbonates, and hydrous minerals. Our measurements indicate that such minerals can be accurately identified using a RAX-like Raman spectrometer. We demonstrated a spectral resolution of approximately 10 cm −1 , high enough to resolve the strongest olivine Raman bands at ~ 820 and ~ 850 cm −1 , with highly sensitive Raman peak measurements (e.g., signal-to-noise ratios up to 100). These results strongly suggest that the RAX instrument will be capable of determining the minerals expected on the surface of Phobos, adding valuable information to address the question of the moon’s origin, heterogeneity, and circum-Mars material transport. Graphical Abstract
OBC-NG is the abbreviation for on-board-computer next generation – a project founded and made by the German Aerospace Center (DLR). The project goal is to provide the basis for future on-board computer (OBC) for space-missions. This document summarizes the conducted work, made in the DLR-project OBC-NG and its predecessor project “Software and Hardware Architecture for Re-configurable Computers”.
The computational demands on spacecraft are rapidly increasing. Current on-board computing components and architectures cannot keep up with the growing requirements. Only a small selection of space-qualified processors and FPGAs are available and current architectures stick with the inflexible cold-redundant structure. The objective of the ongoing project OBC-NG (On-board Computer - Next Generation) is to find new concepts for on-board-computer to fulfill future requirements. The concept presented in this paper is based on a distributed reconfigurable system, consisting of different nodes for processing, management and interface operations. OBC-NG will exploit the high performance of commercial off-the-shelf (COTS) hardware parts. To compensate the shortcomings of COTS parts the OBC-NG redundancy approach differs from the classic way and error mitigation techniques will work mainly on software level. This paper discusses the hardware and software architecture of the system as well as the redundancy and reconfiguration concept. Our ideas will be proven in an OBC-NG prototype, planned for the next year.