Bonjour,

Je viens de trouver un rapport de la NASA sur les moyens de détection et de lutte des objets collisionneurs.

275 pages en glaoush pour justifier le paragraphe ci-dessous, que j'ai à peine survolé.

1.2. Deflection Analysis of Alternatives
The study considered a wide range of techniques to divert a threatening object. These alternatives were broadly classified as “impulsive” if they acted nearly instantaneously, or “slow push” if they acted over an extended period of time. Launch, orbit transfer, technology development, and object characterization requirements were developed for each of these alternatives. They were applied to a set of five scenarios representing the likely range of threats over million-year timescales. The use of nuclear explosives was found to be the most effective alternative in the near term. While an explosion on or below the surface of a threatening object is 10-100 times more effective than a detonation above the surface, the standoff detonation would be less
likely to fragment the target. Nuclear options require the least amount of detailed information about the threatening object. A nuclear standoff mission could be designed knowing only the orbit and approximate mass of the threat, and most impulsive missions could be carried out incrementally to reach the required amount of deflection. Additional information about the object’s mass and physical properties would perhaps increase the
effectiveness, but likely would not be required to accomplish the goal. The study examined conventional explosives, but found they were ineffective against most threats.
Kinetic impact alternatives are the most effective non-nuclear option, transferring 10-100 times less momentum than nuclear options for a fixed launch mass. Impact velocities, varying from 10-50 km/s, produced a factor-of-three variation in deflection performance.
In addition, kinetic impacts also are sensitive to the porosity, elasticity, and composition of the target and may require larger performance margins if these characteristics are not well determined.
Slow push techniques analyzed in this study included a gravity tractor, which would alter the course of an object using the gravitational attraction of a massive spacecraft, and a
space tug, which would attach to an object and move it using high-efficiency propulsion systems. An attached space tug has generally 10-100 times more performance than the gravity tractor, but it requires more detailed characterization data and more robust guidance and control and surface attachment technologies. Slow push techniques were determined to be useful in relatively rare cases (fewer than 1% of expected threat scenarios), but these techniques could be effective in instances where small increments of
velocity (less than 1 mm/s) could be applied to relatively small objects (less than 200 meters in diameter) over many decades.
The level of risk reduction required of a deflection campaign needs to be clearly understood, as it has a first-order impact on cost and complexity. While this report uses a goal of reducing the probability of impact to 1 in 1 million, this is not a nationally or internationally accepted threshold. Additionally, when designing the deflection campaign, planners must take into account that launch vehicles and interplanetary spacecraft fail at
relatively high rates (2-5% for launches; 10+% for spacecraft) and that deflection approaches may not perform as designed. Planning for many flights of multiple spacecraft designs launched from several different launch vehicles may be necessary to achieve the reduction in impact probability projected to be required.
Mais on y trouve, (buznes as usual)

5.20.2. Potential Benefits to Exploration
5.20.2.1. Near-Earth Object Resources This study has identified a loose connection between the goals of the Vision for Space Exploration and a program to survey the population of NEOs. There may come a time when Earth’s resources are insufficient or too costly to support the planet’s growing population. Exploring resources that exist on the Moon, other planets, or NEOs may allow further human expansion.
Et comme par hasard

5.20.3. Potential Synergies with Department of Defense
Potential benefits to DoD and the potential of using DoD assets to augment the NEOsurvey are discussed in Appendix O.
J'en ai pour des mois à lire les dizaines de pages sur le transfert d'énergie

Mais à lire avant:
critique du rapport.

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