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At least 973 records · Page 54

Advanced Utilization of the Payload Executive Processor (PEP) Ethernet Port to Support JSL Based Payloads

Increased interest by Payload Developers in utilization of the Joint Station LAN (Local Area Network) (JSL) for command and data transactions has driven the investigation of providing bi-directional Ethernet communication with PEP (Payload Executive Processor). Ethernet-only payload developers are interested in taking advantage of the services provided by PEP. Enabling Ethernet communications within PEP requires more than just turning on the hardware. PEP contains no Operating System (OS) or Ethernet stack so it does not inherit any built in functionality for Ethernet support. Both hardware drivers and application software must be developed from scratch. In the absence of an OS (Operating System) the design must address security issues in terms of access and data transferred, i.e. blocking unauthorized users and preventing denial of service. Developing a design to process Ethernet data within the existing real-time constraints of PEP requires a few compromises: data rates, supported protocols, custom packet format and limited client connections to name a few. Integration of the light weight internet protocol (LwIP). Ethernet stack provides a customizable solution for the embedded real-time environment. As utilization of the JSL increases, the successful implementation of an Ethernet interface enhances the utilization of PEP, and provides a new path for future Ethernet-only payloads to gain access to around the clock command and data services.

Guyette, Greg↗

Scientific Value of Including an Atmospheric Sample as Part of Mars Sample Return (MSR)

The Perseverance rover is meant to collect samples of the martian surface for eventual return to Earth. The headspace gas present over the solid samples within the sample tubes will be of significant scientific interest for what it reveals about the interactions of the solid samples with the trapped atmosphere and for what it will reveal about the martian atmosphere itself. However, establishing the composition of the martian atmosphere will require other dedicated samples. The headspace gas as the sole atmospheric sample is problematic for many reasons. The quantity of gas present within the sample tube volume is insufficient for many investigations, and there will be exchange between solid samples, headspace gas, and tube walls. Importantly, the sample tube materials and preparation were not designed for optimal Mars atmospheric gas collection and storage as they were not sent to Mars in a degassed evacuated state and have been exposed to both Earth's and Mars' atmospheres. Additionally, there is a risk of unconstrained seal leakage in transit back to Earth, which would allow fractionation of the sample (leak-out) and contamination (leak-in). The science return can be improved significantly (and, in some cases, dramatically) by adding one or more of several strategies listed here in increasing order of effectiveness and difficulty of implementation: (1) Having Perseverance collect a gas sample in an empty sample tube, (2) Collecting gas in a newly-designed, valved, sample-tube-sized vessel that is flown on either the Sample Fetch Rover (SFR) or the Sample Retrieval Lander (SRL), (3) Adding a larger (50-100 cc) dedicated gas sampling volume to the Orbiting Sample container (OS), (4) Adding a larger (50-100 cc) dedicated gas sampling volume to the OS that can be filled with compressed martian atmosphere.

Timothy D. Swindle↗

Case Study of Meteoroid Fluence on a Mars Sample Return Mission

The Mars Sample Return Campaign must satisfy a Back Planetary Protection requirement that limits the risk of biological contamination of the Earth by Martian microbes. The Earth Re-turn Orbiter (ERO), being developed by the European Space Agency (ESA), will carry a Capture, Containment and Return System (CCRS), which is being developed by NASA to retrieve orbiting samples (OS) from Mars orbit, surround them with two containment layers to create a Contained OS (COS), and transfer the COS to the Earth Entry System (EES), which will be re-leased by ERO to carry the samples through entry, descent and landing at the Utah Test and Training Range. Micrometeoroid impact damage to the Thermal Protection System (TPS) of the EES, which may occur at any time in the ERO mission, is recognized as a potential risk driver for loss of sample containment that needs to be rigorously assessed. A Micrometeoroid Protection System (MMPS) will be implemented to limit that risk. The MMPS consists of a shield covering the TPS called the Micrometeoroid Garage (MMG) and a system of cameras to inspect the TPS. An extensive study was performed by the CCRS Project in collaboration with the NASA Engineering and Safety Center (NESC)to assess the probability of damage to the MMG and TPS by meteoroids over the entire ERO mission. This included the computation of the meteoroid fluence on the MMG and directly on the TPS after EES separation, and assessment of damage to the MMG and TPS via hypervelocity impact tests, hydrocode simulations, and empirical damage prediction and ballistic limit equations (BLEs). The focus of this paper is the meteoroid fluence on the MMG.

Micrometeoroid↗

Case Study of Meteoroid Fluence on a Mars Sample Return Mission

The Mars Sample Return Campaign must satisfy a Back Planetary Protection requirement that limits the risk of biological contamination of the Earth by Martian microbes. The Earth Re-turn Orbiter (ERO), being developed by the European Space Agency (ESA), will carry a Capture, Containment and Return System (CCRS), which is being developed by NASA to retrieve orbiting samples (OS) from Mars orbit, surround them with two containment layers to create a Contained OS (COS), and transfer the COS to the Earth Entry System (EES), which will be re-leased by ERO to carry the samples through entry, descent and landing at the Utah Test and Training Range. Micrometeoroid impact damage to the Thermal Protection System (TPS) of the EES, which may occur at any time in the ERO mission, is recognized as a potential risk driver for loss of sample containment that needs to be rigorously assessed. A Micrometeoroid Protection System (MMPS) will be implemented to limit that risk. The MMPS consists of a shield covering the TPS called the Micrometeoroid Garage (MMG) and a system of cameras to inspect the TPS. An extensive study was performed by the CCRS Project in collaboration with the NASA Engineering and Safety Center (NESC)to assess the probability of damage to the MMG and TPS by meteoroids over the entire ERO mission. This included the computation of the meteoroid fluence on the MMG and directly on the TPS after EES separation, and assessment of damage to the MMG and TPS via hypervelocity impact tests, hydrocode simulations, and empirical damage prediction and ballistic limit equations (BLEs). The focus of this paper is the meteoroid fluence on the MMG.

micrometeoroid↗

NASA Capture, Containment, and Return System: Bringing Mars Samples to Earth

The Capture, Containment, and Return System (CCRS) project is NASA’s last step in bringing back Mars samples. CCRS will close a decades-long multi-mission and multi-agency effort to bring Mars surface samples back to Earth for scientific studies. CCRS will launch in 2027 on the European Earth Return Orbiter (ERO) spacecraft, which will provide communications relay for the Mars Sample Return ground missions, Perseverance rover and the Sample Retrieval Lander (SRL) (to be launched in 2028). The main mission for CCRS begins when the first-ever orbital planetary capture operation occurs with CCRS catching and securing the Orbiting Sample (OS)in low Mars orbit. From this point, the system will perform additional "firsts": it will autonomously contain the OS with heat-shrink-fit, sterilize the outside surface, and assemble the Earth entry capsule, named Earth Entry System (EES), in orbit around Mars using a gantry mechanism. At approximately 2.8 Lunar distances from Earth, or 3-days from entry into Earth’s atmosphere, CCRS will open its micrometeoroid shield and release the EES on a ballistic trajectory to Earth. The EES is designed to be a fully passive system that will enter the atmosphere and land without parachute at the Utah Test and Training Range (UTTR).

Mars mission, Sample return, Mission design↗

Overview of the Capture, Containment, and Return System (CCRS)

The Mars Sample Return (MSR) campaign is one of the most ambitious and complex planetary exploration missions currently underway. With the participation of NASA, ESA, and a large number of industry partners, MSR aims to bring Martian soil, rock, and atmospheric samples back to Earth, in order to answer key questions about Mars’ biological evolution. To accomplish this goal the campaign relies on four coordinated missions, each fulfilling a fundamental role to bring the samples to Earth. The Mars Perseverance rover, the first of the four missions, landed safely on Mars on February 18, 2021 and has already acquired candidate samples for Earth return. A selection of the samples of Martian soil and atmosphere that Perseverance has captured during its mission will be recovered, launched into Mars orbit, and transported back to Earth. The Sample Fetch Rover and Mars Ascent System, both parts of the Sample Return Lander project, perform the Mars surface missions to retrieve the collected samples and launch them into Mars orbit. NASA’s Capture, Containment, and Return System (CCRS), hosted on ESA’s Earth Return Orbiter (ERO), brings the samples back to Earth from Mars orbit. These retrieval and return missions are currently in the planning and design stages of development. The NASA-provided CCRS is the payload of the ESA ERO and is the focus of this presentation. ERO will enter Mars orbit and provide communication relay to Earth for the other MSR elements. The Sample Return Lander systems will fetch the sample tubes and integrate them into a protective vessel – the Orbiting Sample (OS) system – which is then launched into low Mars orbit. ERO will perform rendezvous maneuvers, allowing its CCRS payload to capture the OS, contain it, and perform the first automated in-space assembly of a spacecraft, the Earth Entry System (EES), while in Mars orbit. ERO will then begin its journey back to Earth, with CCRS and its assembled EES spacecraft. Three days prior to arrival, CCRS will release the EES on an Earth entry trajectory from a distance beyond the orbit of the Moon. The passive EES spacecraft will then enter Earth’s atmosphere, flying on a ballistic trajectory, followed by a terminal descent (without a parachute) and landing at the Utah Test and Training Range (UTTR). This presentation will show the current design of the CCRS system and its concept of operations. ERO and CCRS will perform several firsts in planetary exploration: (a) orbital rendezvous and capture in Mars orbit, (b) in-space sterilization and containment, (c) on-orbit spacecraft assembly at Mars, and (d) fully-passive entry, descent, and landing sequence for sample return.

Carlie H. Zumwalt↗

A High-Reliability Photoelectric Detection System for Mars Sample Return’s Orbiting Sample

The Mars Sample Return campaign is an endeavor of unprecedented technological complexity and coordination that attempts to answer fundamental questions about the habitability of Mars by returning the first samples of Martian material to Earth for analysis. The third mission in the campaign consists of the NASA-provided Capture, Containment, and Return System (CCRS) onboard the European Space Agency’s Earth Return Orbiter, which will retrieve the Orbiting Sample (OS) container from its orbit around Mars. Retrieving a passive sample container from a planetary orbit has never been attempted by any spacecraft and requires the development of new technology to succeed in this ambitious task. This paper introduces the high-reliability Capture Sensor Suite (CSS), a novel optical detection system that provides CCRS with the capability to autonomously detect the OS as it is captured. This article will discuss the challenges and requirements for the fault-tolerant design of the CSS.

planetary sampling↗

Preliminary Design of Robotic Control Software for Mars Sample Return - Capture, Containment, and Return System

The Mars Sample Return (MSR) campaign aims to acquire and return to Earth a set of Mars samples for investigation in terrestrial laboratories. Mars 2020 has collected an adequate number of samples and deposited them in sealed sample tubes at a designated Martian depot. Sample tubes will be placed in cylindrical containers called Orbiting Samples (OS) by the Perseverance Rover, and later brought to Earth by the Earth Return Orbiter (ERO) and the MSR - Capture, Containment, and Return System (CCRS). Robot Software (RSW) is a set of software processes for commanding and monitoring the avionics that controls robotic mechanisms designed to sterilize and install OS into Earth Entry System (EES) for return to Earth. This paper describes a preliminary design of RSW including motion modes, architecture, and finite state machine. Additionally, software engineering procedures and testing of RSW is provided. A preliminary performance analysis is presented and the paper concludes with future work and a discussion of design decisions.

MSR↗

Pressure-temperature effects on knock with iso-octane and propane at various compression ratios and intake temperatures

Knock remains one of the main limitations for increased internal combustion engine efficiency. Recent trends in light-duty vehicles towards downsized, boosted engines increases the need for improving the understanding between fuel chemistry and thermodynamic effects contributing to knock. Previous studies have shown the importance of end-gas thermodynamic conditions on knock onset and behavior, with relationships to fuel chemistry illustrated. However, a complete understanding of how fuels allow access to higher engine loads and the governing physics behind end-gas knock under a wide range of thermodynamic conditions is still unclear. Experiments in this work improve this understanding with the use of three fuels (1) iso-octane, a low octane sensitivity (OS) fuel (2) a Co-Optima aromatic core fuel, which has similar research octane number (RON) yet significantly higher OS, and (3) propane, known for its knock resistance. Engine load sweeps are conducted with each fuel while maintaining a CA50 of 8 crank angle degrees after top dead center (°CA aTDCf). As load increases and knock onset is observed, spark is delayed to its knock limited spark advance (KLSA) allowing further increases in load until either one of two limits is reached; (1) CA50 retard limit (2) Peak cylinder pressure limit. Experiments are conducted at 40°C and 90°C intake temperature and at two distinct compression ratios (rc) 9.2:1 and 13.6:1. Two-zone zero-dimensional simulations were performed in Chemkin to extract end-gas pressure and temperature conditions through the combustion process for each experimental condition of interest. CA50 response as a function of engine load is compared for all experimental conditions and fuels, and a pressure-temperature (PT) trajectory analysis is conducted using constant volume ignition delay contours to explain the behavior of each fuel.

Dal Forno Chuahy, Flavio↗

An Experimental Feasibility Study on Applying Neutron Tomography to Encapsulated Spent Nuclear Fuel - 20050

Visual inspection makes easier to ensure the integrity and safety of spent nuclear fuel (SNF) than any classical techniques. Various classical techniques have been applied but there are no reliable methods to qualitatively and quantitatively verify spent fuel in dry storage. Thus, the present authors have developed the prototype safeguards apparatus for dry storage employing the array of He-4 gas scintillation detectors (S670E, Arktis Radiation Detectors Ltd., Switzerland), newly designed to simultaneously measure thermal and fast neutrons without any moderators. The S670E detector has a cylindrical shape with a diameter of 52 mm and active length of 600 mm (total length: 875 mm). The detector is filled by He-4 gas with an approximate pressure of 180 bar for fast neutron detection, and its inner wall is coated by Li-6 for thermal neutron detection. The scintillation lights generated via Li-6 nuclear reaction and elastic scattering are collected by 24 SiPMs linearly paired at the center of the detector. The detector delivers a TTL (Transistor-Transistor Logic) output for pulse readout and UART (Universal Asynchronous Receiver Transmitter) for device control. In order to assess feasibility of the apparatus, an experimental system has been designed, built, and optimized via computational studies. Cf-252 neutron sources and linearly arrayed detectors, working as a single detector, were occupied for this study due to the difficulties in working with SNF. The laboratory scale cask (diameter: 0.67 m, height: 1.5 m), minimized by a factor of 10 compared to the actual thickness of a commercial TN-32 cask, was also manufactured. The detector array was designed to rotate the lab-scale cask and obtain 36 image profiles at every 10 degrees. All profiles were aligned in single frame image called a sinogram, and the cross-sectional image was then fabricated by the inverse radon transform algorithm. These experiments have been repeated with different configurations and numbers of sources. Some gamma-ray sources were also measured with neutron sources in order to distinguish between neutron and gamma-ray pulses. Basically, a He-4 detector is designed to run on Linux OS so it is difficult to directly apply to Windows-based equipment widely used in S. Korea. Therefore, a new data acquisition board working on Windows OS was designed and built. The board mainly consists of FPGA (Field Programmable Gate Array) and SoC (System on Chip) for TTL pulse readout, sorting measured data, and transferring data to a user interface. In conclusion, the tomographic system at lab-scale has shown considerable potential to detect a partial or gross defect of encapsulated assemblies in dry storage. Next steps of this study will be to 1) repeatedly carry out experiments to demonstrate scientific reliability and validity, and 2) numerically integrate signals with weight factors to enhance the image quality since the suggested system based on passive interrogation method requires longer measurement time. Finally, the system will apply to a commercial dry storage phased out soon in S. Korea. (authors)

07 ISOTOPE AND RADIATION SOURCES↗

Materials Data on SiOs by Materials Project

OsSi is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Os4+ is bonded in a body-centered cubic geometry to eight equivalent Si4- atoms. All Os–Si bond lengths are 2.56 Å. Si4- is bonded in a body-centered cubic geometry to eight equivalent Os4+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ba2LiOsO6 by Materials Project

Ba2LiOsO6 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Li1+ is bonded to six equivalent O2- atoms to form LiO6 octahedra that share corners with six equivalent OsO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Li–O bond lengths are 2.19 Å. Ba2+ is bonded to twelve equivalent O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with four equivalent LiO6 octahedra, and faces with four equivalent OsO6 octahedra. All Ba–O bond lengths are 2.91 Å. Os7+ is bonded to six equivalent O2- atoms to form OsO6 octahedra that share corners with six equivalent LiO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Os–O bond lengths are 1.91 Å. O2- is bonded in a distorted linear geometry to one Li1+, four equivalent Ba2+, and one Os7+ atom.

36 MATERIALS SCIENCE↗

Materials Data on ZrOs by Materials Project

OsZr is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Zr2+ is bonded in a body-centered cubic geometry to eight equivalent Os2- atoms. All Zr–Os bond lengths are 2.85 Å. Os2- is bonded in a body-centered cubic geometry to eight equivalent Zr2+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on NaLa2OsO6 by Materials Project

NaLa2OsO6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent OsO6 octahedra. The corner-sharing octahedra tilt angles range from 34–39°. There are a spread of Na–O bond distances ranging from 2.32–2.38 Å. La3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.98 Å. Os5+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 34–39°. There is four shorter (1.99 Å) and two longer (2.00 Å) Os–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Na1+, three equivalent La3+, and one Os5+ atom. In the second O2- site, O2- is bonded to one Na1+, two equivalent La3+, and one Os5+ atom to form distorted corner-sharing ONaLa2Os tetrahedra. In the third O2- site, O2- is bonded in a 5-coordinate geometry to one Na1+, three equivalent La3+, and one Os5+ atom.

36 MATERIALS SCIENCE↗

Materials Data on LiPr2OsO6 by Materials Project

LiPr2OsO6 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six equivalent OsO6 octahedra. The corner-sharing octahedra tilt angles range from 32–33°. There are two shorter (2.10 Å) and four longer (2.19 Å) Li–O bond lengths. Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.39–2.77 Å. Os5+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with six equivalent LiO6 octahedra. The corner-sharing octahedra tilt angles range from 32–33°. There is four shorter (1.99 Å) and two longer (2.00 Å) Os–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, three equivalent Pr3+, and one Os5+ atom. In the second O2- site, O2- is bonded to one Li1+, two equivalent Pr3+, and one Os5+ atom to form distorted corner-sharing OLiPr2Os tetrahedra. In the third O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, three equivalent Pr3+, and one Os5+ atom.

36 MATERIALS SCIENCE↗

Materials Data on LiNd2OsO6 by Materials Project

LiNd2OsO6 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six equivalent OsO6 octahedra. The corner-sharing octahedra tilt angles range from 33–34°. There are two shorter (2.09 Å) and four longer (2.19 Å) Li–O bond lengths. Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.36–2.76 Å. Os5+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with six equivalent LiO6 octahedra. The corner-sharing octahedra tilt angles range from 33–34°. There is four shorter (1.99 Å) and two longer (2.00 Å) Os–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, three equivalent Nd3+, and one Os5+ atom. In the second O2- site, O2- is bonded to one Li1+, two equivalent Nd3+, and one Os5+ atom to form distorted corner-sharing OLiNd2Os trigonal pyramids. In the third O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, three equivalent Nd3+, and one Os5+ atom.

36 MATERIALS SCIENCE↗

Materials Data on LiLa2OsO6 by Materials Project

LiLa2OsO6 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six equivalent OsO6 octahedra. The corner-sharing octahedra tilt angles range from 30–31°. There are a spread of Li–O bond distances ranging from 2.11–2.19 Å. La3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.41–2.79 Å. Os5+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with six equivalent LiO6 octahedra. The corner-sharing octahedra tilt angles range from 30–31°. There is four shorter (1.99 Å) and two longer (2.00 Å) Os–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, three equivalent La3+, and one Os5+ atom. In the second O2- site, O2- is bonded to one Li1+, two equivalent La3+, and one Os5+ atom to form distorted corner-sharing OLiLa2Os tetrahedra. In the third O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, three equivalent La3+, and one Os5+ atom.

36 MATERIALS SCIENCE↗

Materials Data on VOs by Materials Project

VOs is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. V2+ is bonded in a body-centered cubic geometry to eight equivalent Os2- atoms. All V–Os bond lengths are 2.62 Å. Os2- is bonded in a body-centered cubic geometry to eight equivalent V2+ atoms.

36 MATERIALS SCIENCE↗