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191.
Peter H. Schultz Carolyn M. Ernst Jennifer L. B. Anderson 《Space Science Reviews》2005,117(1-2):207-239
The NASA Discovery Deep Impact mission involves a unique experiment designed to excavate pristine materials from below the
surface of comet. In July 2005, the Deep Impact (DI) spacecraft, will release a 360 kg probe that will collide with comet
9P/Tempel 1. This collision will excavate pristine materials from depth and produce a crater whose size and appearance will
provide fundamental insights into the nature and physical properties of the upper 20 to 40 m. Laboratory impact experiments
performed at the NASA Ames Vertical Gun Range at NASA Ames Research Center were designed to assess the range of possible outcomes
for a wide range of target types and impact angles. Although all experiments were performed under terrestrial gravity, key
scaling relations and processes allow first-order extrapolations to Tempel 1. If gravity-scaling relations apply (weakly bonded
particulate near-surface), the DI impact could create a crater 70 m to 140 m in diameter, depending on the scaling relation
applied. Smaller than expected craters can be attributed either to the effect of strength limiting crater growth or to collapse
of an unstable (deep) transient crater as a result of very high porosity and compressibility. Larger then expected craters
could indicate unusually low density (< 0.3 g cm−3) or backpressures from expanding vapor. Consequently, final crater size or depth may not uniquely establish the physical
nature of the upper 20 m of the comet. But the observed ejecta curtain angles and crater morphology will help resolve this
ambiguity. Moreover, the intensity and decay of the impact “flash” as observed from Earth, space probes, or the accompanying
DI flyby instruments should provide critical data that will further resolve ambiguities. 相似文献
192.
193.
An essential part of increment preparation for the ISS is the training of the flight crews. Each international partner is responsible for the basic training of its own astronauts, where a basic knowledge is taught on space science and engineering, ISS systems and operations and general astronaut skills like flying, diving, survival, language, etc. The main parts of the ISS crew training are the Advanced Training, e.g., generic ISS operations; nominal and malfunction systems operations and emergencies, and the Increment-Specific Training, i.e., operations and tasks specific to a particular increment. The Advanced and Increment-Specific Training is multilateral training, i.e., each partner is training all ISS astronauts on its contributions to the ISS program. Consequently, ESA is responsible for the Basic Training of its own astronauts and the Advanced and Increment-Specific Training of all ISS crews after Columbus activation on Columbus Systems Operations, Automated Transfer Vehicle (ATV), and ESA payloads.
This paper gives an overview of the ESA ISS Training Program for Columbus Systems Operations and ATV, for which EADS Space Transportation GmbH is the prime contractor. The key training tasks, the training flow and the training facilities are presented. 相似文献
194.
The aim of this paper is to present the time profile of cosmic radiation exposure obtained by the Radiation Risk Radiometer-Dosimeter during the EXPOSE-E mission in the European Technology Exposure Facility on the International Space Station's Columbus module. Another aim is to make the obtained results available to other EXPOSE-E teams for use in their data analysis. Radiation Risk Radiometer-Dosimeter is a low-mass and small-dimension automatic device that measures solar radiation in four channels and cosmic ionizing radiation as well. The main results of the present study include the following: (1) three different radiation sources were detected and quantified-galactic cosmic rays (GCR), energetic protons from the South Atlantic Anomaly (SAA) region of the inner radiation belt, and energetic electrons from the outer radiation belt (ORB); (2) the highest daily averaged absorbed dose rate of 426 μGy d(-1) came from SAA protons; (3) GCR delivered a much smaller daily absorbed dose rate of 91.1 μGy d(-1), and the ORB source delivered only 8.6 μGy d(-1). The analysis of the UV and temperature data is a subject of another article (Schuster et al., 2012 ). 相似文献
195.
The LISA Mission (Laser Interferometer Space Antenna) is currently under mission formulation with a launch date planned in 2020. The purpose of the mission is the observation of gravitational waves at frequencies between 0.1 mHz and 1 Hz by measuring distance fluctuations between inertial reference points, represented by cubic proof masses. In order to provide a sufficient sensitivity of the instrument, distance fluctuations between two inertial reference points must be measured with a strain accuracy of around 10?20 Hz?1/2. This is achieved by setting up a laser interferometer with a base-length of 5?106 km and a path-length measurement noise in the order of 10 pm?Hz?1/2. For a correct evaluation of the data on the ground, it is essential that the science data telemetry preserves all required frequency domain information. That is, any on-board data-processing and down-sampling must be done with great care in order not to introduce aliasing or other artifacts into the data stream. As an additional complication, most of the optical metrology data is dominated by laser phase noise which is about eight orders of magnitude larger than the required instrument sensitivity. However, by applying a method called “time-delayed interferometry” during the ground data processing, this laser phase noise can be eliminated from the data. This method has already been demonstrated in a detailed simulation environment, but it requires a very careful filtering, synchronization, and interpolation of the individual data streams. Last but not least, a calibration of system parameters is necessary in many areas of the LISA measurement system. The system design must therefore ensure that all data required for these calibrations is available on-ground in a quality that allows a successful computation of the calibration coefficients within a reasonable time-frame. The data streams do not only include data from the optical metrology system, but also from the drag-free and attitude control system which are used to derive other information, such as the charge state of the proof mass. This yields a strong coupling between the different disciplines since data that is only used for housekeeping purposes in other missions becomes an essential part of the science data stream for the LISA mission. This paper gives an overview of the LISA measurement and data-processing chain. It highlights the most challenging areas that have been identified so far and describes the intended solution methods. 相似文献