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The input output unit (IOU) for the Attitude and Articulation Subsystem (AACS) for the Cassini spacecraft uses an embedded microprocessor to format and interpret data packets sent over a bus. This new approach is part of a trend toward "smart" peripherals and instruments communicating over much higher bandwidth optical buses.
The contamination control activity performed for the Cassini Imaging Science Subsystem (ISS) consisted of an overall analysis for susceptibility to molecular and particulate contamination at the sensor's most sensitive wavelengths.
The Cassini spacecraft, NASA's mission to investigate the Saturn system, has undergone a system level themal balance test program to permit verification of the engineering subsystem themal designs in the simulated worst-case environments.
The Environmental Development Testing program supported the development test efforts of the Mars 2020 Sampling and Caching Subsystem from May to November 2015. The engineering prototype Brassboard Corer was attached to a five degree-of-freedom robotic arm to execute a 96-test matrix of ambient and low pressure tests in the 10 ft. thermal vacuum chamber at the NASA Jet Propulsion Laboratory, California Institute of Technology. The Pretest, Test, and Post Test procedures are described, and some preliminary results are discussed. Data and observations from this test campaign inform the future development of the software and hardware toward the Mars 2020 flight design, including the next iteration of the rock coring drill, the Engineering Development Unit Corer.
In 1994, SIR-C demonstrated ScanSAR, a mode of operating the SAR system that has become the “standard” implementation for wide-swath spaceborne imaging SAR systems. The NISAR SAR instruments introducing a new SAR architecture for wide-swath imaging call SweepSAR which is expected to have similar success. This paper compares the Antenna and RF subsystem design and the technology utilization considerations between the SIR-C planar phased array SAR system using the ScanSAR technique and NISAR off-set reflector with phased array feed using the SweepSAR technique.
The Cryocooler for the Mid Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) provides cooling at 6.2K on the instrument interface. The cooler system design has been incrementally documented in previous publications [1][2][3][4][5]. It has components that traverse three primary thermal regions on JWST: Region 1, approximated by 40K; Region 2, approximated by 100K; and Region 3, which is at the allowable flight temperatures for the spacecraft bus. However, there are several sub-regions that exist in the transition between primary regions and at the heat reject interfaces of the Cooler Compressor Assembly (CCA) and Cooler Control Electronics Assembly (CCEA). The design and performance of the test facility to provide a flight representative thermal environment for acceptance testing and characterization of the complete MIRI cooler subsystem are presented.
We present experimental results that demonstrate the required in-plane deployment accuracy of the starshade Inner Disk Subsystem (IDS). This effort was to address Milestone 7C of the Starshade Technology Activity S5, which requires that the in-plane deployment accuracy of the petal interfaces on the IDS be within +/-300um. A full-scale 10m-diameter IDS prototype was constructed. This prototype comprised a medium-fidelity perimeter truss, medium-fidelity spokes, and a low-fidelity optical shield (OS). The testbed also included gravity compensation systems and a laser tracker metrology system. The post-processed measurement uncertainties of the laser tracker were less than 30um at the 3 sigma level. Design, engineering and fabrication of these components was done by JPL, Tendeg, and Roccor. Testing was performed at the Tendeg facility in Louisville, Colorado. The IDS prototype was deployed 22 times and the locations of petal interfaces on the IDS were measured after each deployment. Based on this data, tolerance intervals were calculated that would contain 99.73% of future deployment accuracy errors with 90% confidence. These tolerance intervals are conservative estimates for 3 sigma bounds. The tolerance intervals for the three pertinent error components were found to be within the required allocations, with at least 19% margin.
In February 2021, the Mars 2020 Perseverance rover is anticipated to touch down in Jezero crater, Mars. Perseverance is unique in that it will conduct in situ science as well as cache samples for eventual return to Earth for analysis in terrestrial laboratories. It will explore the geologic setting within Jezero over a range of scales in order to address fundamental questions about the evolution of Mars and assess whether there is evidence of past or present Martian life. The Wide Angle Topographic Sensor for Operations and eNgineering (WATSON), one of two imaging subsystems within the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument[1,2], acquires images that support scientific study of Jezero crater and sample acquisition, as well as rover and instrument operations(Fig. 1).WATSON serves a number of roles; it 1) provides color context imaging of SHERLOC and Planetary Instrument for X-Ray Litho chemistry (PIXL)analysis locations, placing the spatial distribution of organics and mineralogy detected by SHERLOC and the elemental maps generated by PIXL within the context of rock texture and structure; 2)acquires stand-alone observations of rock structures and textures from the outcrop to the grain scale; and 3)images rover components and other instruments to monitor their health and condition. We plan to present images acquired within the first ~30 sols of operations.
The Sealing Station is composed of two mechanisms: the Gripper Mechanism, for orientation and support of the Sample Tube during the Hermetic Seal activation activity, as well as ejecting Sample Tubes out of the Rover, and the Ram Mechanism, which produces and applies a high force for seal activation. The Ram Mechanism is a compact high force linear actuator that uses a planetary roller screw (PRS) as the output linear stage, tapered roller bearings (TRB) to support the PRS at the high loads, a set of spur gears supported by cylinder roller bearings, and a brushless motor with a planetary gearhead and magnetic detent brake. This paper describes the role of these mechanisms in the Mars 2020 Rover mission as a part of the Sample Caching Subsystem (SCS) and Adaptive Caching Assembly (ACA) and their interactions with the Hermetic Seal and Sample Tube hardware. We report on development testing performed with the PRS that show it has capability of supporting cross-moment loads, something manufacturers of these components do not rate. Also discussed is the interaction of the passive holding torque from magnetic detent brakes and hardstop preload, setting of a very light preload in the TRB, and the complex linear dyno test equipment used, and how that testing could have been improved.
Outline - Magnetic latching cryogenic (CryMag) coupler - Overview - Requirements - Magnetic subsystem design - Advantages & disadvantages - Design overview - Testing results - Thermal extremes - Force profile - Conclusions
We present the status of ongoing work at NASA’s Goddard Space Flight Center (GSFC) to build a prototype, low-cost-of-production, flexibly-configured ground terminal for space optical communication. For laser telecommunication to be cost effective for future missions, a wide-spread global network of operationally responsive optical terminals should be established. There has been a decades-old need for a single modular open systems approach (MOSA) ground terminal architecture capable of supporting multiple space missions ranging from LEO to Lunar distances with 2-way laser communications. At the heart of LCOT’s design concept is the Free-Space Optical Subsystem (FSOS). The major subassemblies of LCOT/FSOS that address most optical common configurations are : (1) Single 700mm F/12 Nasmyth folded Rx R-C Telescope, (2) Four independent 150mm diameter high-power all-reflective Tx beam directors (XOA), (3) Non-coherent direct detection Rx bench on starboard side of telescope (SOB), and (4) Coherent (possibly Quantum) optical communications bench on port side (POB). The Low-Cost Optical Terminal (LCOT) research and development (R&D) prototype is designed to be a generalized system that can be quickly field-reconfigured to support a wide variety of laser communications missions past, present, & future.
Outline - Magnetic latching cryogenic (CryoMag) coupler - Overview - Requirements - Magnetic subsystem - Patterned magnetic interfaces - Design & operation - Testing results - Thermal extremes - Force profile - Conclusions & future work
In this paper we present a comparative study of the losses associated with fiber-coupled single-photon detectors in two different configurations, each with the goal of receiving a pulsed-position modulated signal with a maximum data rate of 267 Mbps. First, we consider a 7x1 few-mode-fiber (FMF) photonic lantern coupled to seven individual superconducting nanowire single photon detectors (SNSPDs). In the second configuration we assess a single FMF coupled to a 16-channel monolithic SNSPD array. In each case we measure and compare combined fiber coupling, SNSPD blocking, and system efficiency losses under emulated atmospheric turbulence conditions. We address subsystem impact on link performance and analyze feasibility for future NASA lunar and deep-space optical communications missions.
A comparative study of the losses associated with fiber-coupled single-photon detectors in two different configurations, each with the goal of receiving a pulsed-position modulated signal with a maximum data rate of 267 Mbps. First, we consider a 7x1 few-mode-fiber (FMF) photonic lantern coupled to seven individual superconducting nanowire single photon detectors (SNSPDs). In the second configuration we assess a single FMF coupled to a 16-channel monolithic SNSPD array. In each case we measure and compare combined fiber coupling, SNSPD blocking, and system efficiency losses under emulated atmospheric turbulence conditions. We address subsystem impact on link performance and analyze feasibility for future NASA lunar and deep-space optical communications missions.
Psyche is a Discovery-class mission to the small metal-rich asteroid (16) Psyche, and is slated to launch in 2022. Psyche, like many missions, requires low-cost activity planning and sequence generation that serves as the backbone to overall uplink design. Such tools must be maintainable over long periods of operations, and powerful enough to solve complex issues that deep-space one-off missions encounter. In this paper we introduce cost-effective solutions that leverage inner- and open-source principles to meet a variety of common and novel use cases.The uplink process that was designed to meet these challenges is presented, as well as the data-flow through the high-level architecture of the planning software subsystem. The user-facing planning tools are described, particularly the Science Opportunity Analyzer, the Plan Editor, Psyche’s planning automation in the Blackbird framework, and Psyche Simulation Reports. All these applications are either new or have been substantially revamped to meet Psyche’s concept of operations. In particular, ensuring the entire toolchain can correctly process epoch-relative activities is discussed. Underlying the main applications are a common set of dependencies developed and maintained by a new cross-mission association of planning developers. In this way, Psyche can inherit well-tested functionality which saves effort and ensures its developers can focus on solving domain challenges. Quality control of the applications and libraries is ensured with a code-review and unit-test based novel ‘CM lite’ process. Collaboration with international industry and academia using the open-source modules is already occurring.The planning and scheduling software is designed to maximize operator awareness of the integrated plan at every step of the process and use common interfaces and file formats to easily transfer information. Design choices plus the team’s test-driven development process enables more expansive capabilities compared to the decentralized planning and sequence generation functions typical of Discovery-class orbiters without significant development cost increases. Benefits and drawbacks of Psyche’s approach are discussed, including comparison to other missions and tools where appropriate.
As Human spaceflight evolves and develops, the technology the crew relies on for life support must become more advanced than at any point in NASA’s history. Nowhere is this more apparent than the Gateway, where lessons learned from Mercury to ISS are being applied in the design and production of the life support systems. Some of these technological improvements are proven in flight configuration, or have a heritage of proven flight hardware, but many are of a lower technology readiness level. Due to the unpredictable nature of the metabolic byproducts (CO 2 , H 2 O, and heat), even the proven technologies can fail to meet requirements for crew safety. Detailed modeling of individual components excels in proving component level requirements are met, but fails to verify system or architecture level requirements. This paper expounds upon an effort to take a number of detailed component level models of the Gateway ECLSS and integrate them into a larger architecture model known as the Gateway Integrated ECLSS Model (GIEM). The GIEM is then used to study how the subsystems work synergistically to meet environmental requirements as well as investigate how changes at the component level effect the Gateway stack as a whole.
To support NASA’s goal to return to the Moon through the Artemis Mission, the development of an Exploration Portable Life Support Subsystem (xPLSS) has been conducted at Johnson Space Center (JSC). As part of this development process, a large system level thermal/fluid model of the xPLSS was developed using Thermal Desktop and an in-house human model (METMAN). The xPLSS model was used throughout the design process to predict the performance and temperature of nearly all components within the xPLSS. In the fall of 2023, the Design, Verification, and Testing (DVT) unit of the xPLSS was tested in a thermal vacuum (TVAC) chamber at JSC. This testing consisted of combining the xPLSS with an upper torso of the Exploration Pressure Garment System (xPGS) and simulating five Extravehicular Activities (EVAs) in extreme thermal conditions (two cold EVAs and three hot EVAs). The data generated in this test series provided system level data of the xPLSS operating in vacuum and at flight-like environmental temperatures for the first time. These data were compared to results output by the xPLSS system model to assess the accuracy of previous analyses and improve the fidelity and accuracy of the xPLSS system model. The comparison between model and test hardware provides valuable insight that will help improve the design and fidelity of next generation space suits. In general, comparison between test data and model data generally showed slightly un-conservative values (model predicting colder temperatures than test in hot environments, and hotter temperatures than test in cold environments). Model assumptions and test assumptions were assessed to understand potential causes of some of these sources in error. Recommendations to improve the fidelity of the xPLSS model were also made based on the results presented in this paper.
NASA’s Exploration and In-Space Services (NExIS) Division has been developing technologies for the on-orbit servicing of satellites for decades (Hubble servicing missions) On-Orbit Servicing, Assembly and Manufacturing mission 1 (OSAM-1) had plans to robotically refuel a heritage satellite on-orbit (a.k.a. non-cooperative) Future plans of the OSAM-1 flight hardware will not be discussed The OSAM-1 Space Infrastructure Dexterious Robot (SPIDER) payload is designed to assemble a 3-meter communications antenna OSAM-1 Propellant Transfer Subsystem (PTS) development supports the nascent in-space refueling ISAM goals Reference “National In-Space Servicing, Assembly, and Manufacturing Implementation Plan” (Dec 2022 from White House Office of Science and Technology Policy) ISAM fluid transfer technology shortfalls still exist and are actively being addressed at NASA