Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Mars Rover”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Mars rover RTG study

The paper describes the design and analysis of radioisotope thermoelectric generators (RTGs) for powering the Mars rover vehicle, which is a critical element of the unmanned Mars Rover and Sample Return mission (MRSR). A brief description is given of a reference mission scenario, an illustrative rover design and activity pattern on Mars, power system requirements, and environmental constraints, including the RTG cooling requirements during transit to Mars. The key RTG design problem, i.e. venting the helium generated by the fuel's alpha decay without intrusion of the Martian atmosphere into the RTG, is identified and a design approach to solve that problem is proposed. The study's primary objective is to quantify the performance improvements achievable in new successfully developed technologies, to estimate the required time, effort, success probability, and programmatic risk in developing these new technologies, and thus to help identify the best strategy for meeting the MRSR system goals. Finally, the paper compares the RTGs' specific powers for different power levels (250W vs 125W), different thermoelectric element designs (standard vs short unicouples vs multicouples), and different thermoelectric figures of merit (0.00058K to the -1 to 0.00140K to the -1).

Schock, A.↗
NASA NTRS2021

Automated Data Accountability for Missions in Mars Rover Data

As the Mars Curiosity Rover transmits data to the JPL Ground Data System (GDS), it frequently observes data loss and corruption, requiring re-transmits from the rover and Ground Data System Analysts (GDSA) to monitor the downlink process. As new missions are launched, the GDSA team redistributes analysts to these new missions, causing shortages in previous missions. The GDSA team can significantly benefit from the automation and optimization of the downlink process of telemetry data. In fact, there is a need for a better understanding of why the data is corrupted, so that the GDSA team can best determine the root cause of the issues in the GDS. This paper presents machine learning and deep learning based approaches to automate and optimize the detection of data loss. We first created a pipeline to automatically accumulate data from the telemetry databases (MAROS, Telemetry Data Storage, and GDS Elastic Search Database) in the downlink process. With our newly created datasets, we perform feature selection to supplement the GDSA understanding of the downlink process and provide supplemental analysis on the importance of different features. We implement various machine learning and deep learning based models, including support vector machines, ensemble methods, and deep neural networks and evaluate their accuracies in identifying whether a downlink process is complete or incomplete. We utilize fast hyperparameter optimization methods that allow our models to quickly be re-trained, allowing them to quickly be tuned and optimized on daily incoming data in real time. This hyperparameter optimization also allows our methods to be quickly integrated into other JPL missions. Our results show that our best-performing machine learning and deep learning based models outperform the existing GDSA detection software by 6 accuracy points and can aid analysts by providing insights into the data accountability problem. Since these various machine learning and deep learning approaches vary significantly in interpretability, we provide a discussion on the tradeoffs between their performance and trustworthiness in helping detect issues in data transmission.

Divsalar, Dariush↗
NASA NTRS2004

Small-RPS Enabled Mars Rover Concept

Both the MER and the Mars Pathfinder rovers operated on Mars in an energy-limited mode, since the solar panels generated power during daylight hours only. At other times the rovers relied on power stored in batteries. In comparison, Radioisotope Power Systems (RPS) offer a power-enabled paradigm, where power can be generated for long mission durations (measured in years), independently from the Sun, and on a continuous basis. A study was performed at PL to assess the feasibility of a small-RPS enabled MER-class rover concept and any associated advantages of its mission on Mars. The rover concept relied on design heritage from MER with two significant changes. First, the solar panels were replaced with two single GPHS module based small-RPSs. Second, the Mossbauer spectroscope was substituted with a laser Raman spectroscope, in order to move towards MEPAG defined astrobiology driven science goals. The highest power requirements were contributed to mobility and telecommunication type operating modes, hence influencing power system sizing. The resulting hybrid power system included two small-RPSs and two batteries. Each small-RPS was assumed to generate 50We of power or 62OWh/sol of energy (BOL), comparable to that of MER. The two 8Ah batteries were considered available during peak power usage. Mission architecture, power trades, science instruments, data, communication, thermal and radiation environments, mobility, mass issues were also addressed. The study demonstrated that a new set of RPS-enabled rover missions could be envisioned for Mars exploration within the next decade, targeting astrobiology oriented science objectives, while powered by 2 to 4 GPHS modules.

Mars exploration↗
NASA NTRS1993

Mars rover mechanisms designed for Rocky 4

A Mars rover prototype vehicle named Rocky 4 was designed and built at JPL during the fall of 1991 and spring 1992. This vehicle is the fourth in a series of rovers designed to test vehicle mobility and navigation software. Rocky 4 was the first attempt to design a vehicle with 'flight like' mass and functionality. It was consequently necessary to develop highly efficient mechanisms and structures to meet the vehicles very tight mass limit of 3 Kg for the entire mobility system (7 Kg for the full system). This paper will discuss the key mechanisms developed for the rover's innovative drive and suspension system. These are the wheel drive and strut assembly, the rocker-bogie suspension mechanism and the differential pivot. The end-to-end design, analysis, fabrication and testing of these components will also be discussed as will their performance during field testing. The lessons learned from Rocky 4 are already proving invaluable for the design of Rocky 6. Rocky 6 is currently being designed to fly on NASA's MESUR mission to Mars scheduled to launch in 1996.

Rivellini, Tommaso P.↗
NASA NTRS1989

Mars Rover and Sample Return Mission design

The current reference Mars Rover and Sample Return mission is described. Technical issues are outlined, including high-resolution image acquisition and reconstruction, approach navigation, ground and flight systems operational complexity, rover autonomy, autonomous rendezvous and docking in Mars orbit, aerocapture and aeromaneuver, estimating the probability of mission success, and end-to-end information system design. Focus is placed on lander hazard identification and avoidance, pinpoint landing guidance and control, Mars ascent vehicle guidance and control, planetary protection and quarantine, sample acquisition and preservation, project management and control, systems requirements and interface control, and costing. In addition, program issues such as international participation, fiscal constraints, and launch-vehicle availability are considered.

Kwok, Johnny H.↗
NASA NTRS1980

A propulsion system for the Mars rover vehicle

The vehicle control electronics for the Mars rover vehicle is described. A functional description of the electronics and its place in the entire system is given. The hardware involved is described from a user's point of view. Changes and additions to the software are included.

Bogdan, D. C.↗
NASA NTRS1989

Possible use of pattern recognition for the analysis of Mars rover X-ray fluorescence spectra

On the Mars rover sample-return mission, the rover vehicle will collect and select samples from different locations on the Martian surface to be brought back to earth for laboratory studies. It is anticipated that an in situ energy-dispersive X-ray fluorescence (XRF) spectrometer will be on board the rover. On such a mission, sample selection is of higher priority than in situ quantitative chemical anlaysis. With this in mind, a pattern recognition technique is proposed as a simple, direct, and speedy alternative to detailed chemical analysis of the XRF spectra. The validity and efficacy of the pattern recognition technique are demonstrated by the analyses of laboratory XRF spectra obtained from a series of geological samples, in the form both of standardized pressed pellets and as unprepared rocks. It is found that pattern recognition techniques applied to the raw XRF spectra can provide for the same discrimination among samples as a knowledge of their actual chemical composition.

Yin, Lo I↗
NASA NTRS2003

Students Work Alongside Scientists to Test Mars Rover

NASA's 2003-2004 Mars Exploration Rovers and associated Athena Science Payload will provide an exciting opportunity to get students and the public involved in Mars exploration. One outreach component, the Athena Student Interns Program, will directly engage high school students in scientific discovery on Mars by incorporating the students into the mission s science team. The Athena Student Interns Program, based on the successful LAPIS program, was prototyped during the FIDO rover field trials that took place in the Arizona desert and at the Jet Propulsion Laboratory (JPL) in August 2002 (http://mars.jpl.nasa.gov/mer/fido). Use of a participatory evaluation process allowed mid-course corrections to be made to the program and provided the model for mission-related outreach.

Fuchs, M. P.↗
NASA NTRS1990

Design of a Mars rover and sample return mission

The design of a Mars Rover Sample Return (MRSR) mission that satisfies scientific and human exploration precursor needs is described. Elements included in the design include an imaging rover that finds and certifies safe landing sites and maps rover traverse routes, a rover that operates the surface with an associated lander for delivery, and a Mars communications orbiter that allows full-time contact with surface elements. A graph of MRSR candidate launch vehice performances is presented.

Bourke, Roger D.↗
NASA NTRS1993

International testing of a Mars rover prototype

Tests on a prototype engineering model of the Russian Mars 96 Rover were conducted by an international team in and near Death Valley in the United States in late May, 1992. These tests were part of a comprehensive design and testing program initiated by the three Russian groups responsible for the rover development. The specific objectives of the May tests were: (1) evaluate rover performance over different Mars-like terrains; (2) evaluate state-of-the-art teleoperation and autonomy development for Mars rover command, control and navigation; and (3) organize an international team to contribute expertise and capability on the rover development for the flight project. The range and performance that can be planned for the Mars mission is dependent on the degree of autonomy that will be possible to implement on the mission. Current plans are for limited autonomy, with Earth-based teleoperation for the nominal navigation system. Several types of television systems are being investigated for inclusion in the navigation system including panoramic camera, stereo, and framing cameras. The tests used each of these in teleoperation experiments. Experiments were included to consider use of such TV data in autonomy algorithms. Image processing and some aspects of closed-loop control software were also tested. A micro-rover was tested to help consider the value of such a device as a payload supplement to the main rover. The concept is for the micro-rover to serve like a mobile hand, with its own sensors including a television camera.

Kemurjian, Alexsandr Leonovich↗
NASA NTRS1988

Mars Rover Sample Return mission delivery and return challenges

The Mars Rover Sample Return mission is a robotic exploration mission culminating in the return of atmospheric and surface samples from Mars to Earth. To accomplish this complex mission requires sophisticated autonomous systems for many time-critical operations associated with the delivery and return phases, since the round trip light times preclude Earth-based control of these operations. In addition, there are significant engineering and technology challenges to be addressed to meet the mission science and exploration objectives.

Cohen, Aaron↗
NASA NTRS1991

Shielding analysis for a manned Mars rover powered by an SP-100 type reactor

Shield design is one of the most crucial tasks in the integration of a nuclear reactor power system to a manned Mars rover. A multilayered W and LiH shield is found to minimize the shield mass and satisfy the dose rate limit of 30 rem/y to the rover crew. The effect on dose rate of tungsten layers thicknesses and position within the lithium hydride shields is investigated. Due to the large cross section for the W (n,gamma) reaction, secondary gammas become a significant radiation source. The man-rated shield mass for the Mars rover vehicle is correlated to the reactor thermal power. The correlation fits to within 9 percent of the calculated shield mass and results in an uncertainty of below 4 percent in the overall rover mass. The shield mass varied from 8600 kg to 20580 kg for a reactor thermal power of 100 to 1000 kW(t), respectively.

Morley, Nicholas J.↗
NASA NTRS2006

Targeting and Localization for Mars Rover Operations

In this work we discuss how the quality of localization knowledge impacts the remote operation of rovers on the surface of Mars. We look at the techniques of localization estimation used in the Mars Pathfinder and Mars Exploration Rover missions. We examine the motivation behind the modes of targeting for different types of activities, such as navigation, remote science, and in situ science. We discuss the virtues and shortcomings of existing approaches and new improvements in the latest operations tools used to support the Mars Exploration Rover missions and rover technology development tasks at the Jet Propulsion Laboratory. We conclude with future directions we plan to explore in improving the localization knowledge available for operations and more effective targeting of rovers and their instrument payloads.

remote rover operations↗
NASA NTRS2004

Pancam Mast Assembly on Mars Rover

The Pancam Mast Assembly (PMA) for the 2003 Mars Rover is a deployable structure that provides an elevated platform for several cameras. The PMA consists of several mechanisms that enable it to raise the cameras as well as point the cameras in all directions. This paper describes the function of the various mechanisms as well as a description of the mechanisms and some test parameters. Designing these mechanisms to operate on the surface of Mars presented several challenges. Typical spacecraft mechanisms must operate in zero-gravity and high vacuum. These mechanisms needed to be designed to operate in Martian gravity and atmosphere. Testing conditions were a little easier because the mechanisms are not required to operate in a vacuum. All of the materials are vacuum compatible, but the mechanisms were tested in a dry nitrogen atmosphere at various cold temperatures.

Warden, Robert M.↗
NASA NTRS1987

A Mars rover for the 1990's

Some technical issues concerning a Mars rover launched in the 1990s are discussed. Two particular modes of controlling the traveling of the vehicle are described. In one mode, most of the control is from earth, by human operators viewing stereo pictures sent from the rover and designating short routes to follow. In the other mode, computer vision is used in order to make the rover more autonomous, but reliability is aided by the use of orbital imagery and approximate long routes sent from earth. In the latter case, it is concluded that average travel rates of around 10 km/day are feasible.

Wilcox, Brian H.↗