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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Performance Testing of Yardney Li-Ion Cells and Batteries in Support of Future NASA Missions

NASA requires lightweight rechargeable batteries for future missions to Mars and the outer planets that are capable of operating over a wide range of temperatures, with high specific energy and energy densities. Due to the attractive performance characteristics, Li-ion batteries have been identified as the battery chemistry of choice for a number of future applications. For example, JPL is planning to launch another unmanned rover mission to the planet Mars. This mission, referred to as the Mars Science Laboratory (MSL), will involve the use of a rover that is much larger than the previously developed Spirit and Opportunity Rovers for the 2003 Mars Exploration Rover (MER) mission, that are currently still in operation on the surface of the planet after more than five years. Part of the reason that the MER rovers have operated so successfully, far exceeding the required mission duration of 90 sols, is that they possess robust Li-ion batteries, manufactured by Yardney Technical Products, which have demonstrated excellent life characteristics. Given the excellent performance characteristics displayed, similar Li-ion batteries have been projected to successfully meet the mission requirements of the up-coming MSL mission. In addition to future missions to Mars, Li-ion technology is attractive for a number of other future NASA applications which require high specific energy, rechargeable batteries. To ascertain the viability of using Li-ion batteries for these applications, a number of performance validation tests have been performed on both Yardney cells and batteries of various sizes. These tests include mission simulation tests, charge and discharge rate characterization testing, cycle life testing under various conditions, and storage testing.

Smart, M. C.↗
NASA NTRS2015

Mars Exploration Rover Spirit End of Mission Report

The Mars Exploration Rover (MER) Spirit landed in Gusev crater on Mars on January 4, 2004, for a prime mission designed to last three months (90 sols). After more than six years operating on the surface of Mars, the last communication received from Spirit occurred on Sol 2210 (March 22, 2010). Following the loss of signal, the Mars Exploration Rover Project radiated over 1400 commands to Mars in an attempt to elicit a response from the rover. Attempts were made utilizing Deep Space Network X-Band and UHF relay via both Mars Odyssey and the Mars Reconnaissance Orbiter. Search and recovery efforts concluded on July 13, 2011. It is the MER project's assessment that Spirit succumbed to the extreme environmental conditions experienced during its fourth winter on Mars. Focusing on the time period from the end of the third Martian winter through the fourth winter and end of recovery activities, this report describes possible explanations for the loss of the vehicle and the extent of recovery efforts that were performed. It offers lessons learned and provides an overall mission summary.

Callas, John L.↗
NASA NTRS2014

Calculation of Operations Efficiency Factors for Mars Surface Missions

The duration of a mission--and subsequently, the minimum spacecraft lifetime--is a key component in designing the capabilities of a spacecraft during mission formulation. However, determining the duration is not simply a function of how long it will take the spacecraft to execute the activities needed to achieve mission objectives. Instead, the effects of the interaction between the spacecraft and ground operators must also be taken into account. This paper describes a method, using "operations efficiency factors", to account for these effects for Mars surface missions. Typically, this level of analysis has not been performed until much later in the mission development cycle, and has not been able to influence mission or spacecraft design. Further, the notion of moving to sustainable operations during Prime Mission--and the effect that change would have on operations productivity and mission objective choices--has not been encountered until the most recent rover missions (MSL, the (now-cancelled) joint NASA-ESA 2018 Mars rover, and the proposed rover for Mars 2020). Since MSL had a single control center and sun-synchronous relay assets (like MER), estimates of productivity derived from MER prime and extended missions were used. However, Mars 2018's anticipated complexity (there would have been control centers in California and Italy, and a non-sun-synchronous relay asset) required the development of an explicit model of operations efficiency that could handle these complexities. In the case of the proposed Mars 2018 mission, the model was employed to assess the mission return of competing operations concepts, and as an input to component lifetime requirements. In this paper we provide examples of how to calculate the operations efficiency factor for a given operational configuration, and how to apply the factors to surface mission scenarios. This model can be applied to future missions to enable early effective trades between operations design, science mission planning, and spacecraft design.

Laubach, Sharon↗
NASA NTRS2019

Sulfur on Mars

The S contents of rocks and soils are indicative of various alteration processes on Mars, e.g.[1]. It has been quantified along traverses at 4 landing sites – Pathfinder, both MERs and MSL – by the APXS [2,3]. At the MSL and MER sites, sulfur abundances, correlations with likely bound cations and other elements, and complementary mineralogical and textural data have provided important insights into alteration processes and periods of more habitable environments in the distant past.

Gellert, R.↗
NASA NTRS2006

Implementing distributed operations : a comparison of two Deep Space Missions

Two very different deep space exploration missions—Mars Exploration Rover and Cassini—have made use of distributed operations for their science teams. In the case of MER, the distributed operations capability was implemented only after the prime mission was completed, as the rovers continued to operate well in excess of their expected mission lifetimes; Cassini, designed for a prime mission of four years, had planned for distributed operations from its inception. The rapid command turnaround timeline of MER, as well as many of the operations features implemented to support it, have proven to be conducive to distributed operations. These features include: a single science team leader during the tactical operations timeline, highly integrated science and engineering teams, processes and file structures designed to permit multiple team members to work in parallel to deliver sequencing products, web-based spacecraft status and planning reports for team-wide access, and near-elimination of paper products from the operations process.

Larsen, Barbara↗
NASA NTRS2003

Gusev Meridiani will look different : radar scattering properties of the Mars Exploration Rover landing sites

Analysis of all existing radar data for the two Mars Exploration Rover (MER) landing sites at Meridiani Planum and Gusev Crater suggest that their meter-scale morphological appearance will be noticeably different than previous Mars landing sites; their "human-scale", decimeter- to meter-scal roughness is not the same as for previous Mars landing sites. We make this prediction based on the comparison of the MER landing sites.

Harmon, J. K.↗
NASA NTRS2007

Visual end-effector position error compensation for planetary robotics

This paper describes a vision-guided manipulation algorithm that improves arm end-effector positioning to subpixel accuracy and meets the highly restrictive imaging and computational constraints of a planetary robotic flight system. Analytical, simulation-based, and experimental analyses of the algorithm's effectiveness and sensitivity to camera and arm model error is presented along with results on several prototype research systems and ground-in-the-loop technology experiments on the Mars Exploration Rover (MER) vehicles. A computationally efficient and robust subpixel end-effector fiducial detector that is instrumental to the algorithm's ability to achieve high accuracy is also described along with its validation results on MER data.

Nickels, Kevin↗
NASA NTRS2006

Advances in distributed operations and mission activity planning for Mars surface exploration

A centralized mission activity planning system for any long-term mission, such as the Mars Exploration Rover Mission (MER), is completely infeasible due to budget and geographic constraints. A distributed operations system is key to addressing these constraints; therefore, future system and software engineers must focus on the problem of how to provide a secure, reliable, and distributed mission activity planning system. We will explain how Maestro, the next generation mission activity planning system, with its heavy emphasis on portability and distributed operations has been able to meet these design challenges. MER has been an excellent proving ground for Maestro's new approach to distributed operations. The backend that has been developed for Maestro could benefit many future missions by reducing the cost of centralized operations system architecture.

Shams, Khawaja↗
NASA NTRS2017

Thermal Development of the Mars 2020 Enhanced Engineering Cameras

The engineering cameras (ECAMs) of the 2003 Mars Exploration Rover (MER) mission were re-flown on the Mars Science Laboratory (MSL) mission that launched in 2011. The upcoming Mars 2020 rover mission will introduce a new fleet of cameras called the enhanced engineering cameras (EECAMs). These EECAMs will have improved imaging capability, as the technology of the past ECAMs flown on Mars surface missions have become outdated. The EECAMs include six upgraded HazCams, two upgraded NavCams, and a single, newly-conceived CacheCam. The purposes of the HazCams and NavCams remain the same as they were for MER and MSL: to detect hazards to the front and rear of the rover, and to help in navigation across the Martian surface. The CacheCam will be used to take images of samples obtained by the rover’s Sample Caching System. This paper compares the differences in the thermal designs of the ECAMs and EECAMs, their design drivers, and their implications for the mission operations of the Mars 2020 rover.

Novak, Keith S.↗
NASA NTRS2022

Formal Methods for Trusted Space Autonomy, Boon or Bane?

Trusted Space Autonomy is challenging in that space systems are complex artifacts deployed in a high stakes environment with complicated operational settings. Thus far these challenges have been met using the full arsenal of tools: formal methods, informal methods, testing, runtime techniques, and operations processes. Using examples from previous deployments of autonomy to the Remote Agent on DS-1, Autonomous Sciencecraft on EO-1, WATCH on MER, IPEX, AEGIS on MER, MSL, and M2020, and the M2020 Onboard planner, we discuss how each of these approaches have been used to enable successful deployment of autonomy. We next focus on relatively limited use of formal methods (both prior to deployment and runtime methods). From the needs perspective, formal methods represent the best chance for reliable autonomy as testing, informal methods, and operations accommodations do not scale well with increasing complexity of the autonomous system. However from the practice perspective, formal methods have been limited in their application due to difficulty in eliciting formal specifications and challenges in representing complex constraints such as metric time and resources. We discuss some of these challenges as well as the opportunity to extend formal and informal methods into runtime validation systems.

Chien, Steve↗
NASA NTRS2022

Multi-Mission Terrain Classifier for Safe Rover Navigation and Automated Science

We previously presented Soil Property and Object Classification (SPOC), a machine learning-based terrain classifier for Mars rovers, for automatically segmenting rover images by its surface type such as sand and bedrock. This paper presents a number of practical improvements to pave the way for potential future onboard deployment. First, we achieved 97.0% overall pixel accuracy, evaluated against the classification generated by human experts on images from Mars Science Laboratory (MSL) missions. The substantial increase in accuracy was primarily enabled by the sheer volume of data used for training; we created a new large-scale dataset of Martian terrain labels, namely AI4Mars, which contains more than 400k labels contributed by citizen scientists for 50k images taken by the Mars Exploration Rovers (MER) and Mars Science Laboratory (MSL) rover. Second, we demonstrated that SPOC can quickly adapt to a new mission landed on a previously unseen site. Specifically, we pretrained a model with MER and MSL data from the AI4Mars dataset and then adapted to the Mars 2020 Rover (M2020) by feeding a small volume of data between Sol 0 and 157; the adapted model was tested on Sol 200-203 and resulted in 84.2% overall pixel accuracy and 93.4% reliability (recall) for detecting sand, the most concerning class for rover’s traversability. Third, we found that pretraining can substantially mitigate the decline of accuracy over time. We showed that the performance of a SPOC model pretrained with the ImageNet dataset and then trained by MSL images only up to Sol 390 remains comparable to a model trained by images up to Sol 1689 on the test data after Sol 1689. Fourth, we reimplemented SPOC with a light-weight convolutional neural network (CNN), MobileNetV2, which typically runs within tens of milliseconds (ms) on mobile processors such as Qualcomm’s Snapdragon. Finally, we released the AI4Mars dataset to the public to encourage open innovation.

Ono, Masahiro↗
DOE OSTI2022

SARS-CoV-2 Diverges from Other Betacoronaviruses in Only Partially Activating the IRE1α/XBP1 Endoplasmic Reticulum Stress Pathway in Human Lung-Derived Cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has killed over 6 million individuals worldwide and continues to spread in countries where vaccines are not yet widely available or its citizens are hesitant to become vaccinated. Therefore, it is critical to unravel the molecular mechanisms that allow SARS-CoV-2 and other coronaviruses to infect and overtake the host machinery of human cells. Coronavirus replication triggers endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR), a key host cell pathway widely believed to be essential for viral replication. We examined the master UPR sensor IRE1α kinase/RNase and its downstream transcription factor effector XBP1s, which is processed through an IRE1α-mediated mRNA splicing event, in human lung-derived cells infected with betacoronaviruses. We found that human respiratory coronavirus OC43 (HCoV-OC43), Middle East respiratory syndrome coronavirus (MERS-CoV), and murine coronavirus (MHV) all induce ER stress and strongly trigger the kinase and RNase activities of IRE1α as well as XBP1 splicing. In contrast, SARS-CoV-2 only partially activates IRE1α through autophosphorylation, but its RNase activity fails to splice XBP1. Moreover, while IRE1α was dispensable for replication in human cells for all coronaviruses tested, it was required for maximal expression of genes associated with several key cellular functions, including the interferon signaling pathway, during SARS-CoV-2 infection. Our data suggest that SARS-CoV-2 actively inhibits the RNase of autophosphorylated IRE1α, perhaps as a strategy to eliminate detection by the host immune system.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

MCL004

Omics-Lethal Human Virus, MERS - MCL004

100 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

MCL005

Omics-Lethal Human Virus, MERS - MCL005

101 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2003

Mars Exploration Rover parachute decelerator system program review

In the Mars Exploration Rover (MER) Mission, NASA returns to the red planet, following the extremely successful Mars Pathfinder in 1997. The mission will send two lander-rovers to the surface of Mars with separate launches in May and June, 2003. This paper describes the Parachute Decelerator System for the entry vehicle.

Mars Exploration Rover MER parachute decelerator s↗