Rubble-Pile Near Earth Objects: Insights from Granular Physics

Daniels, Karen E.

doi:10.1007/978-3-642-39244-3_11

Cited by 8 publications

(3 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many space missions are motivated for scientific, or exploration reasons, often requiring a contact with the surface, or landing and manoeuvring. Response of the surface during anchoring, drilling, or sampling is of the utmost importance and needs a better understanding of the physics of granular media in low gravitational conditions (Daniels 2013). The same applies for mitigation in space of a Potentially Hazardous Asteroid (PHA) that would likely impact the Earth.…”

Section: Summary and Open Questionsmentioning

confidence: 99%

Small Solar System Bodies as granular media

Hestroffer

Sánchez

Staron

et al. 2019

Astron Astrophys Rev

View full text Add to dashboard Cite

show abstract

Section: Summary and Open Questionsmentioning

confidence: 99%

Small Solar System Bodies as granular media

Hestroffer

Sánchez

Staron

et al. 2019

Astron Astrophys Rev

View full text Add to dashboard Cite

show abstract

“…In low gravity the impact mechanics for a granular material may be very different to the impact mechanics under Earth gravity as the shearing strength will be greatly reduced because of the lower gravitational acceleration (Daniels, 2013). However it is often impractical to make such simulations and spacecraft landings are often simulated with targets under Earth's gravity.…”

Section: Test Rigmentioning

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

View full text Add to dashboard Cite

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.

show abstract

“…Most NEAs are understood to be "rubble-piles" or unconsolidated rock fragments held together by electrostatic, Van der Waal, and gravitational forces (Daniels 2013;Mazanek et al 2015). A popular suggestion is to concentrate metallic phases by combing their surfaces with an electromagnetic rake (Kargel 1994).…”

mentioning

confidence: 99%

Igneous Rock Associations 24. Near-Earth Asteroid Resources: A Review

Innis

Osinski

2019

View full text Add to dashboard Cite

The extraction of natural resources located beyond Earth to create products can be described as space resource utilization (SRU). SRU is under active investigation in both the public and private sectors. Near-Earth asteroids (NEAs) are particularly promising early SRU targets due to their relative proximity and enrichments in two key resources: water and platinum group elements (PGEs). Water can be used to create rocket propellant, making it the only resource with significant demand given the current nascent state of the space market. Platinum group elements are valuable enough that their import to the Earth market is potentially economical, making them the other prospective resource in the current embryonic state of SRU. While it is possible to retrieve material from a NEA, doing so on an economical scale will require significant developments in areas such as autonomous robotics and propulsion technology. A parameterization accounting for asteroid size, resource concentration, and accessibility yields just seven and three potentially viable NEA targets in the known population for water and PGEs, respectively. A greater emphasis on spectral observation of asteroids is required to better inform target selection for early prospecting spacecraft. A further complication is the lack of a legal precedent for the sale of extraterrestrial resources. The Outer Space Treaty prohibits the appropriation of celestial bodies but makes no explicit reference to their resources while the U.S.A. and Luxembourg have passed legislation entitling their citizens to own and sell space resources. Whether these laws are a matter of clarification or contradiction is the matter of some debate. RÉSUMÉL'extraction de ressources naturelles situées au-delà de la Terre pour créer des produits peut être décrite comme une utilisation des ressources spatiales (URS). L’URS est actuellement examinée à la fois dans les secteurs public et privé. Les astéroïdes proches de la Terre (NEA) sont des cibles URS particulièrement prometteuses en raison de leur proximité relative et de leur enrichissement en deux ressources clés : l’eau et les éléments du groupe du platine (EGP). L'eau peut être utilisée pour créer des agents de propulsion pour vaisseaux spatiaux, ce qui en fait la seule ressource pour laquelle la demande est importante compte tenu de l’émergence du marché spatial actuel. Les EGP sont suffisamment précieux pour que leur importation sur le marché terrestre soit potentiellement économique, ce qui en fait l’autre ressource potentielle étant donné l’état embryonnaire actuel de l’URS. Bien qu'il soit possible de récupérer des matériaux sur un NEA, le faire à une échelle économique nécessitera des développements importants dans des domaines tels que la robotique autonome et la technologie de propulsion. Un paramétrage tenant compte de la taille des astéroïdes, de la concentration des ressources et de l'accessibilité conduit à seulement sept et trois cibles NEA parmi la population connue, potentiellement exploitables pour l'eau et les EGP, respectivement. Il est nécessaire de mettre davantage l'accent sur l'observation spectrale des astéroïdes afin de mieux documenter la sélection des cibles pour les premiers vaisseaux prospecteurs. L'absence de précédent juridique pour la vente de ressources extraterrestres est une complication supplémentaire. Le Traité sur l’espace interdit l’appropriation des corps célestes mais ne fait aucune référence explicite à leurs ressources, tandis que les États-Unis et le Luxembourg ont adopté une législation autorisant leurs citoyens à posséder et à vendre des ressources spatiales. Que ces lois fassent l’objet de clarification ou de contradiction est sujet à débat.

show abstract

Rubble-Pile Near Earth Objects: Insights from Granular Physics

Cited by 8 publications

References 84 publications

Small Solar System Bodies as granular media

Small Solar System Bodies as granular media

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

Igneous Rock Associations 24. Near-Earth Asteroid Resources: A Review

Contact Info

Product

Resources

About