Engineering topics

Hutton, R. E.

Publications and source records attributed to Hutton, R. E..

17 records

NASA NTRS1982

A summary of Viking sample-trench analyses for angles of internal friction and cohesions

Analyses of sample trenches excavated on Mars, using a theory for plowing by narrow blades, provide estimates of the angles of internal friction and the cohesions of the Martian surface materials. Angles of internal friction appear to be the same as those of many terrestrial soils because they are generally between 27 degrees and 39 degrees. Drift material, at the Lander 1 site, has a low angle of internal friction (near 18 degrees). All the materials excavated have low cohesions, generally between 0.2 and 10 kPa. The occurrence of cross bedding, layers of crusts, and blocky slabs shows that these materials are heterogeneous and that they contain planes of weakness. The results reported here have significant implications for future landed missions, Martian eolian processes, and interpretation of infrared temperatures.

Moore, H. J.↗

NASA NTRS1980

Surface erosion caused on Mars from Viking descent engine plume

During the Martian landings the descent engine plumes on Viking Lander 1 (VL-1) and Viking Lander 2 (VL-2) eroded the Martian surface materials. This had been anticipated and investigated both analytically and experimentally during the design phase of the Viking spacecraft. This paper presents data on erosion obtained during the tests of the Viking descent engine and the evidence for erosion by the descent engines of VL-1 and VL-2 on Mars. From these and other results, it is concluded that there are four distinct surface materials on Mars: (1) drift materials, (2) crusty to cloddy material, (3) blocky material, and (4) rock.

Hutton, R. E.↗

NASA NTRS1979

Sample fields of the Viking landers, physical properties, and aeolian processes

Surface sampler activities on Mars during the Viking extended mission are considered, including excavation of deep trenches, construction of conical piles of materials, backhoe touchdown experiments, and acquisition of contiguous pictures of the surface beneath number 2 terminal descent engines using mirrors. Results of the Physical Properties Investigation that are relevant to aeolian processes are also discussed. Both pictures and surface sampler data indicate that the surface materials in the sample fields of the Viking landers may be grouped, in order of increasing strength, into drift material, crusty to cloddy material, blocky material and rocks.

Moore, H. J.↗

NASA NTRS1977

Surface materials of the Viking landing sites

In the present paper, the soil characteristics at the Viking sites are discussed in terms of bulk density, particle size, angle of internal friction, cohesion, and moisture content. At the Viking Lander-1 site, there is a relatively weak drift material, along with more cohesive materials of a rocky area, and rocks. A variety of materials are present also at the Lander-2 site. Moisture content is low as compared to terrestrial soils. Current estimates of some of the physical properties are tabulated and discussed.

Moore, H. J.↗

NASA NTRS1976

The environs of Viking 2 lander

Forty-six days after Viking 1 landed, Viking 2 landed in Utopia Planitia, about 6500 kilometers away from the landing site of Viking 1. Images show that in the immediate vicinity of the Viking 2 landing site the surface is covered with rocks, some of which are partially buried, and fine-grained materials. The surface sampler, the lander cameras, engineering sensors, and some data from the other lander experiments were used to investigate the properties of the surface. Lander 2 has a more homogeneous surface, more coarse-grained material, an extensive crust, small rocks or clods which seem to be difficult to collect, and more extensive erosion by the retroengine exhaust gases than lander 1. A report on the physical properties of the Martian surface based on data obtained through sol 58 on Viking 2 and a brief description of activities on Viking 1 after sol 36 are given.

Shorthill, R. W.↗

NASA NTRS1976

The 'soil' of Mars /Viking 1/

The immediate environs of the Viking 1 lander are described, and the techniques employed to deduce the properties of the two different 'soil' types there are summarized. It is shown that the surface in the immediate vicinity of the lander consists of an area with fine-grained materials ('Sandy Flats') and a rocky area set in a matrix of finer-grained material ('Rocky Flats'). Estimates are given for the bulk density, particle density, particle size distribution, cohesion, angle of internal friction, and penetration resistance of the surface layer in each area. Footpad penetration into the surface layer is discussed, and wind removal of particles is examined. It is concluded that the surface layer of the Viking 1 landing site contains loess, dune sand, lunar nominal soil, lag gravel, and bare rock.

Shorthill, R. W.↗

NASA NTRS1976

Physical properties of the Martian surface from the Viking 1 lander - Preliminary results

Examination of the erosion of the surface of Mars caused by the descent engines of the Viking 1 lander indicates that the soil is stronger and/or denser than the 'lunar nominal' soil (an artificially produced soil with a particle size distribution similar to results for lunar soils obtained by Apollo 11) used in preflight site alteration tests. There is further evidence to suggest that the finer grains are not as small as those of the lunar nominal material, and that the soil under the lander footpads is relatively stiff. The crater, depressions, and ejecta associated with the impact of a latch pin which fell from the surface sampler are consistent with terrestrial soils with very low cohesions, small grain size, and a density of 1.2 to 1.7 g/cu cm.

Shorthill, R. W.↗

NASA NTRS1969