An impact penetrometer for a landing spacecraft

Lorenz, Ralph D.; Bannister, Michele T.; Daniell, P. M.; Krysiński, Z; Leese, M. R.; Miller, Rosalind; Newton, Gill; Rabbetts, P.; Willett, D.M.; Zarnecki, J. C.

doi:10.1088/0957-0233/5/9/001

Cited by 30 publications

(22 citation statements)

References 3 publications

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“…The low speed but high mass of the lander will then push the penetrometer into the shallow subsurface. This technique was used by the Huygens landing on Titan (Lorenz et al, 1994;Zarnecki et al, 2005). Impact penetrometry is particularly valuable when visiting a body for the first time (Jones, 1971;Spohn et al, 2015).…”

Section: Regolith Structure and Microstructure Measured By A Landing mentioning

confidence: 99%

“…A conventional spacecraft with a mass of around 100 kg landing at a few metres per second, with a penetrometer fitted to its base, has enough momentum to deliver sensors into the sub-surface of an asteroid or other planetary regolith by virtue of its high mass (Lorenz et al, 1994;Paton et al, 2015). Despite the low speed, the high mass of the spacecraft presents a momentum comparable to, if not exceeding, the values obtained by low mass, high speed penetrators.…”

Section: Introductionmentioning

confidence: 99%

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Detection of structure in asteroid analogue materials and Titan’s regolith by a landing spacecraft

Paton

Green

Ball

et al. 2016

Advances in Space Research

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We compare measurements made by two impact penetrometers of different sizes and with different tip shapes to further understand penetrometer design for performing pentrometry on an asteroid. To this end we re-visit the interpretation of data from the Huygens' penetrometer, ACC-E, that impacted Titan's surface. In addition we investigate the potential of a spacecraft fitted with a penetrometer to bounce using a test rig, built at The Open University (UK).Analysis of ACC-E laboratory data, obtained from impacts into ∼4 mm diameter gravel, was found to produce an unusual decrease in resistance with depth (force-depth gradient) which was also seen in the Huygens' ACC-E data from Titan and originally interpreted as a wet or moist sand. The downward trend could also be reproduced in a hybrid Discrete Element Model (DEM) if it was assumed that the near surface particles are more readily * Corresponding author mobilised than those deeper in the target. With regard to penetrometer design penetration resistance was found to be sensitive to the ratio of particle to tip diameter. A clear trend was observed with a conical tip penetrometer, X-PEN, of decreasing force-depth gradients with increasing particle sizes most likely due to a transformation from a bulk displacement of material by the penetrating tip to more local interactions. ACC-E, which has a hemispherical tip, was found to produce a wider range of force-depth gradients than X-PEN, which had a conical tip, possibly due to difficulties dislodging jammed particles. Both penetrometers were able to determine particle diameter and mass after post-processing of the data.Laboratory simulations of landings with the test rig suggest that a large impact penetrometer under certain circumstances could absorb a significant amount of the elastic energy of the spacecraft possibly aiding landing. Alternatively a small impact penetrometer would allow the spacecraft to bounce freely off the surface to make a measurement at another location.

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Section: Regolith Structure and Microstructure Measured By A Landing mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection of structure in asteroid analogue materials and Titan’s regolith by a landing spacecraft

Paton

Green

Ball

et al. 2016

Advances in Space Research

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“…Penetrometry utilising parts of the spacecraft structure, such as landing pads, is limited to the top few centimetres of the surface and is useful for determining bearing capacity and for insights into weathering and volatile exchange processes. Such investigations into the top centimetres of a regolith, shown in figure 2, were performed on the Moon by the Surveyor landing legs (Jones, 1971) and on Titan by the Huygens probe with a penetrometer mounted on its base ( Lorenz et al, 1994). A penetrometer, deployed from the spacecraft, such as the MUPUS thermal probe (Spohn et al, 2007), can allow deeper access perhaps reaching layers that are insulated from surface processes and provide information on long-term processes.…”

Section: Subsurface Exploration Possibilities Using Penetrometers Andmentioning

confidence: 99%

“…The ACC-E penetrometer measures force during penetration using a piezoelectric sensor housed behind a hemispherical tip (Lorenz et al, 1994). It is well characterised and therefore well suited to validating penetrometry measurements made by X-PEN.…”

Section: Laboratory Copy Of the Huygens Penetrometer (Acc-e)mentioning

confidence: 99%

Using the inertia of spacecraft during landing to penetrate regoliths of the Solar System

Paton

Green

Ball

et al. 2015

Advances in Space Research

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The high inertia, i.e. high mass and low speed, of a landing spacecraft has the potential to drive a penetrometer into the subsurface without the need for a dedicated deployment mechanism, e.g., during Huygens landing on Titan. Such a method could complement focused subsurface exploration missions, particularly in the low gravity environments of comets and asteroids, as it is conducive to conducting surveys and to the deployment of sensor networks. We make full-scale laboratory simulations of a landing spacecraft with a penetrometer attached to its base plate. The tip design is based on that used in terrestrial Cone Penetration Testing (CPT) with a large enough shaft diameter to house instruments for analysing pristine subsurface material. Penetrometer measurements are made in a variety of regolith analogue materials and target compaction states. For comparison a copy of the ACC-E penetrometer used on the Huygens mission is used. A test rig at the Open * Corresponding author University is used and is operated over a range of speeds from 0.9 to 3 m sand under two gravitational accelerations. The penetrometer was found to be sensitive to the target's compaction state with a high degree of repeatability. The penetrometer measurements also produced unique pressure profile shapes for each material. Measurements in limestone powder produced an exponential increase in pressure with depth possibly due to increasing compaction with depth. Measurements in sand produced an almost linear increase in pressure with depth. Iron powder produced significantly higher pressures than sand presumably due to the rough surface of the grains increasing the grain-grain friction. Impacts into foamglas produced with both ACC-E and the large penetrometer produced an initial increase in pressure followed by a leveling off as expected in a consolidated material. Measurements in sand suggest that the pressure on the tip is not significantly dependent on speed over the range tested, which suggests bearing strength equations could be applied to impact penetrometry in sand-like regoliths.In terms of performance we find the inertia of a landing spacecraft, with a mass of 100 kg, is adequate to penetrate regoliths expected on the surface of Solar System bodies. Limestone powder, an analogue for a dusty surface, offered very little resistance allowing full penetration of the target container. Both iron powder, representing a stronger coarse grained regolith, and foamglas, representing a consolidated comet crust, could be penetrated to similar depths of around two to three tip diameters, probably more if impacting with a slightly higher speed.

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“…Beswick, 1964;McCarty et al, 1964). Impact accelerometry will be performed on the anchor harpoons of the Rosetta lander (KoÈ mle et al, 1997) to deduce cometary subsurface structure, and on the Huygens probe (Lorenz et al, 1994) to determine the hardness of Titan's unknown surface.…”

Section: Introductionmentioning

confidence: 99%

Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry

Lorenz

Moersch

Stone

et al. 2000

Planetary and Space Science

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We describe the results of three separate sets of impact tests conducted during the development of the DS-2 Mars Microprobe mission. As well as indicating the promise of penetration to H0.5 m depth on Mars, these tests show the utility of accelerometer data in determining the penetration depth, the hardness of the surface material and the existence of layers, and the presence of coarse-grained material. Various lessons learned in instrumentation and operation, airgun testing and target characterization, and penetrator design for reliable separation, are discussed. 7

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An impact penetrometer for a landing spacecraft

Cited by 30 publications

References 3 publications

Detection of structure in asteroid analogue materials and Titan’s regolith by a landing spacecraft

Detection of structure in asteroid analogue materials and Titan’s regolith by a landing spacecraft

Using the inertia of spacecraft during landing to penetrate regoliths of the Solar System

Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry

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