scholarly journals Prospects for Implementing Variable Emittance Thermal Control of Space Suits on the Martian Surface

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Christopher J. Massina ◽  
David M. Klaus
Keyword(s):  
Environmental Parameters ◽  
Landing Site ◽  
Thermal Control ◽  
Control Mechanisms ◽  
Martian Surface ◽  
Solar Absorption ◽  
Heat Rejection ◽  
Extravehicular Activity ◽  
Space Suits ◽  
Rejection Mechanism

Extravehicular activity (EVA) will play an important role as humans begin exploring Mars, which, in turn, will drive the need for new enabling technologies. For example, space suit heat rejection is currently achieved through the sublimation of ice water to the vacuum of space, a mechanism widely regarded as not feasible for use in Martian environment pressure ranges. As such, new, more robust thermal control mechanisms are needed for use under these conditions. Here, we evaluate the potential of utilizing a full suit, variable emittance radiator as the primary heat rejection mechanism during Martian surface EVAs. Diurnal and seasonal environment variations are considered for a latitude 27.5°S Martian surface exploration site. Surface environmental parameters were generated using the same methods used in the initial selection of the Mars Science Laboratory's initial landing site. This evaluation provides theoretical emittance setting requirements to evaluate the potential of the system's performance in a Mars environment. Parametric variations include metabolic rate, wind speed, radiator solar absorption, and total radiator area. The results showed that this thermal control architecture is capable of dissipating a standard nominal EVA metabolic load of 300 W in all the conditions with the exception of summer noon hours, where a supplemental heat rejection mechanism with a 250 W capacity must be included. These results can be used to identify when conditions are most favorable for conducting EVAs. The full suit, variable emittance radiator architecture provides a viable means of EVA thermal control on the Martian surface.

Regenerable Non-Venting Thermal Control Subsystem for Extravehicular Activity, 1986

1986 ◽  
Author(s):  
George J. Roebelen ◽  
Stephen A. Bayes ◽  
B. Mike Lawson
Keyword(s):  
Thermal Control ◽  
Extravehicular Activity ◽  
Control Subsystem

scholarly journals Seismic investigations of the Martian near-surface at the InSight landing site

2020 ◽  
Author(s):  
Cedric Schmelzbach ◽  
Nienke Brinkman ◽  
David Sollberger ◽  
Sharon Kedar ◽  
Matthias Grott ◽  
...  
Keyword(s):  
Deep Structure ◽  
Landing Site ◽  
P Wave ◽  
Mission Design ◽  
Normal Operation ◽  
Seismic Signals ◽  
Martian Surface ◽  
Broadband Seismometer ◽  
Near Surface ◽  
Martian Regolith

<p>The InSight ultra-sensitive broadband seismometer package (SEIS) was installed on the Martian surface with the goal to study the seismicity on Mars and the deep interior of the Planet. A second surface-based instrument, the heat flow and physical properties package HP<sup>3</sup>, was placed on the Martian ground about 1.1 m away from SEIS. HP<sup>3</sup> includes a self-hammering probe called the ‘mole’ to measure the heat coming from Mars' interior at shallow depth to reveal the planet's thermal history. While SEIS was designed to study the deep structure of Mars, seismic signals such as the hammering ‘noise’ as well as ambient and other instrument-generated vibrations allow us to investigate the shallow subsurface. The resultant near-surface elastic property models provide additional information to interpret the SEIS data and allow extracting unique geotechnical information on the Martian regolith.</p><p>The seismic signals recorded during HP<sup>3</sup> mole operations provide information about the mole attitude and health as well as shed light on the near-surface, despite the fact that the HP<sup>3 </sup>mole continues to have difficulty penetrating below 40 cm (one mole length). The seismic investigation of the HP<sup>3</sup> hammering signals, however, was not originally planned during mission design and hence faced several technical challenges. For example, the anti-aliasing filters of the seismic-data acquisition chain were adapted when recording the mole hammering to allow recovering information above the nominal Nyquist frequency. In addition, the independently operating SEIS, HP<sup>3</sup> and lander clocks had to be correlated more frequently than in normal operation to enable high-precision timing.</p><p>To date, the analysis of the hammering signals allowed us to constrain the bulk P-wave velocity of the volume between the mole tip and SEIS (top 30 cm) to around 120 m/s. This low velocity value is compatible with laboratory tests performed on Martian regolith analogs with a density of around 1500 kg/m<sup>3</sup>. Furthermore, the SEIS leveling system resonances, seismic recordings of atmospheric pressure signals, HP<sup>3</sup> housekeeping data, and imagery provide additional constraints to establish a first seismic model of the shallow (topmost meters) subsurface at the landing site.</p>

scholarly journals COMPARISON AND CO-REGISTRATION OF DEMS GENERATED FROM HiRISE AND CTX IMAGES

2016 ◽  
Vol XLI-B4 ◽  
pp. 511-517
Author(s):  
Yiran Wang ◽  
Bo Wu
Keyword(s):  
Landing Site ◽  
Systematic Investigation ◽  
Topographic Mapping ◽  
High Resolution Imaging ◽  
Complex Environment ◽  
Martian Surface ◽  
Mars Rover ◽  
Digital Elevation ◽  
Imaging Science ◽  
Resolution Imaging

Images from two sensors, the High-Resolution Imaging Science Experiment (HiRISE) and the Context Camera (CTX), both on-board the Mars Reconnaissance Orbiter (MRO), were used to generate high-quality DEMs (Digital Elevation Models) of the Martian surface. However, there were discrepancies between the DEMs generated from the images acquired by these two sensors due to various reasons, such as variations in boresight alignment between the two sensors during the flight in the complex environment. This paper presents a systematic investigation of the discrepancies between the DEMs generated from the HiRISE and CTX images. A combined adjustment algorithm is presented for the co-registration of HiRISE and CTX DEMs. Experimental analysis was carried out using the HiRISE and CTX images collected at the Mars Rover landing site and several other typical regions. The results indicated that there were systematic offsets between the HiRISE and CTX DEMs in the longitude and latitude directions. However, the offset in the altitude was less obvious. After combined adjustment, the offsets were eliminated and the HiRISE and CTX DEMs were co-registered to each other. The presented research is of significance for the synergistic use of HiRISE and CTX images for precision Mars topographic mapping.

scholarly journals IMPROVED LARGE-SCALE SLOPE ANALYSIS ON MARS BASED ON CORRELATION OF SLOPES DERIVED WITH DIFFERENT BASELINES

2017 ◽  
Vol XLII-3/W1 ◽  
pp. 155-161
Author(s):  
Y. Wang ◽  
B. Wu
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Landing Site ◽  
Martian Surface ◽  
Low Resolution ◽  
Slope Analysis ◽  
Digital Elevation ◽  
Surface Slopes ◽  
Global Coverage ◽  
The Relationship

The surface slopes of planetary bodies are important factors for exploration missions, such as landing site selection and rover manoeuvre. Generally, high-resolution digital elevation models (DEMs) such as those generated from the HiRISE images on Mars are preferred to generate detailed slopes with a better fidelity of terrain features. Unfortunately, high-resolution datasets normally only cover small area and are not always available. While lower resolution datasets, such as MOLA, provide global coverage of the Martian surface. Slopes generated from the low-resolution DEM will be based on a large baseline and be smoothed from the real situation. In order to carry out slope analysis at large scale on Martian surface based low-resolution data such as MOLA data, while alleviating the smoothness problem of slopes due to its low resolution, this paper presents an amplifying function of slopes derived from low-resolution DEMs based on the relationships between DEM resolutions and slopes. First, slope maps are derived from the HiRISE DEM (meter-level resolution DEM generated from HiRISE images) and a series of down-sampled HiRISE DEMs. The latter are used to simulate low-resolution DEMs. Then the high-resolution slope map is down- sampled to the same resolution with the slope map from the lower-resolution DEMs. Thus, a comparison can be conducted pixel-wise. For each pixel on the slope map derived from the lower-resolution DEM, it can reach the same value with the down-sampled HiRISE slope by multiplying an amplifying factor. Seven sets of HiRISE images with representative terrain types are used for correlation analysis. It shows that the relationship between the amplifying factors and the original MOLA slopes can be described by the exponential function. Verifications using other datasets show that after applying the proposed amplifying function, the updated slope maps give better representations of slopes on Martian surface compared with the original slopes.

scholarly journals Evaluating Lumbar Shape Deformation With Fabric Strain Sensors

2020 ◽  
pp. 001872082096530
Author(s):  
Linh Q. Vu ◽  
Han Kim ◽  
Lawrence J. H. Schulze ◽  
Sudhakar L. Rajulu
Keyword(s):  
Injury Risk ◽  
Body Shape ◽  
Human Motion ◽  
The Body ◽  
Strain Sensors ◽  
Body Motion ◽  
Space Suit ◽  
Extravehicular Activity ◽  
Shape Prediction ◽  
Space Suits

Objective To better study human motion inside the space suit and suit-related contact, a multifactor statistical model was developed to predict torso body shape changes and lumbar motion during suited movement by using fabric strain sensors that are placed on the body. Background Physical interactions within pressurized space suits can pose an injury risk for astronauts during extravehicular activity (EVA). In particular, poor suit fit can result in an injury due to reduced performance capabilities and excessive body contact within the suit during movement. A wearable solution is needed to measure body motion inside the space suit. Methods An array of flexible strain sensors was attached to the body of 12 male study participants. The participants performed specific static lumbar postures while 3D body scans and sensor measurements were collected. A model was created to predict the body shape as a function of sensor signal and the accuracy was evaluated using holdout cross-validation. Results Predictions from the torso shape model had an average root mean square error (RMSE) of 2.02 cm. Subtle soft tissue deformations such as skin folding and bulges were accurately replicated in the shape prediction. Differences in posture type did not affect the prediction error. Conclusion This method provides a useful tool for suited testing and the information gained will drive the development of injury countermeasures and improve suit fit assessments. Application In addition to space suit design applications, this technique can provide a lightweight and wearable system to perform ergonomic evaluations in field assessments.

Defining a Discretized Space Suit Surface Radiator With Variable Emissivity Properties

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Christopher J. Massina ◽  
David M. Klaus
Keyword(s):  
Heat Flux ◽  
Constant Temperature ◽  
Thermal Control ◽  
Constant Heat Flux ◽  
Order Estimate ◽  
Space Suit ◽  
Constant Heat ◽  
Load Range ◽  
Heat Rejection ◽  
Integration Architecture

Heat rejection for space suit thermal control is typically achieved by sublimating water ice to vacuum. Converting the majority of a space suit's surface area into a radiator may offer an alternative means of heat rejection, thus reducing the undesirable loss of water mass to space. In this work, variable infrared (IR) emissivity electrochromic materials are considered and analyzed as a mechanism to actively modulate radiative heat rejection in the proposed full suit radiator architecture. A simplified suit geometry and lunar pole thermal environment is used to provide a first-order estimate of electrochromic performance requirements, including number of individually controllable pixels and the emissivity variation that they must be able to achieve to enable this application. In addition to several implementation considerations, two fundamental integration architecture options are presented—constant temperature and constant heat flux. With constant temperature integration, up to 48 individual pixels with an achievable emissivity range of 0.169–0.495 could be used to reject a metabolic load range of 100 W–500 W. Alternatively, with constant heat flux integration, approximately 400 pixels with an achievable emissivity range of 0.122–0.967 are required to reject the same load range in an identical external environment. Overall, the use of variable emissivity electrochromics in this capacity is shown to offer a potentially feasible solution to approach zero consumable loss thermal control in space suits.

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