A method for calculating the resistance of spacecraft design elements under the action of space debris particles

In this paper, the problems of the application and development of models of space debris when designing means of the anti-meteorite spacecraft protection are considered. The developed method enables us to calculate the resistance of design elements based on the conjugation of a modified spatial model of the distribution of space-debris particles and ballistic limit dependences for a calculated element.     

The results of flight tests of an attitude control system for the Chibis-M microsatellite

The attitude control system of the Chibis-M microsatellite is described. Results of flight experiments on damping the initial angular velocity (made using magnetorquers) are considered, as well as stabilization in the orbital referece frame, and orientation of solar arrays toward the Sun using reaction wheels. The operation of algorithms of satellite attitude determination on sunlit and shadow segments of the orbit is also under study. The general logic of operation of the attitude control system in automatic mode is presented and discussed.     

Crew autonomy for deep space exploration: Lessons from the Antarctic Search for Meteorites

Future piloted missions to explore asteroids, Mars, and other targets beyond the Moon will experience strict limitations on communication between vehicles in space and control centers on Earth. These limitations will require crews to operate with greater autonomy than any past space mission has demonstrated. The Antarctic Search for Meteorites (ANSMET) project, which regularly sends small teams of researchers to remote parts of the southern continent, resembles a space mission in many ways but does not rely upon a control center. It provides a useful crew autonomy model for planners of future deep space exploration missions. In contrast to current space missions, ANSMET gives the crew the authority to adjust competing work priorities, task assignments, and daily schedules; allows the crew to be the primary monitor of mission progress; demands greater crew accountability for operational errors; requires the crew to make the most of limited communication bandwidth; adopts systems designed for simple operation and failure recovery; and grants the crew a leading role in the selection and stowage of their equipment.     

High velocity impact characterization of Al alloys for oblique impacts

This paper describes the experimental and computational analyses of a high velocity aluminum projectile impact on an Al6061-T6 spacecraft inner wall at different oblique angles. Al2017-T4 spherical projectiles of 5.56 mm in diameter and 0.25 g in weight were chosen within the velocity range of 1000±200 m/s due to the limitation of the light gas gun. The energy absorbed was calculated by measuring the velocities before and after impact on the inner wall. The energy absorbed by the wall and the remaining energy carried by the projectile helped to estimate the severity of further damage to inner components. Afterwards, validation was done by using the commercially available software LS-DYNA with a dedicated SPH. On average, a 10% energy absorption difference between experimentation and simulation was found. By using C-SCAN, the damage area proportion of the total inner wall to impact penetration hole area was found to be on average 6%, 26% and 53% greater than the projectile cross sectional area for the oblique angle impacts of 30°, 45°, and 60°, respectively. These findings helped to understand the relationship between the oblique impact event and the damage area on a spacecraft inner wall along with space debris cloud propagation and comparison with experimental results using LS-DYNA.     

Analysis and pre-development of an imaging spectrometer for in-situ cometary soil analysis on-board the esa rosetta mission

The CIVA-M instrument, a highly integrated infrared/visible microscope for the Rosetta mission (ESA — 2003) is presented. It will enable scientists to study in great detail the composition of the Wirtanen Comet: minerals, organic compounds and ices. A monochromator will illuminate a cometary sample, drilled from the comet sub-surface (≈40cm). An infrared detector will give an image of the sample for each wavelength, from 1 to 4μm with a spectral resolution of 6nm and a spatial resolution of 50 μm. In order to analyze accurately spectra a signal to noise ratio of 50 is needed (for ALBEDO = 0.04). We will use a 128×128 elements photovoltaic mercury cadmium telluride bi-dimensional array working at intermediate temperature (110K to 150K), from the French company SOFRADIR. At such relatively high temperature the critical parameter is the dark current: it limits the exposure time, preventing a high signal to noise ratio. I am in charge of the electronic board, which is the interface between the detector and the on-board processor. Some preliminary results obtained with this board, on a test detector, are then discussed.     

Autonomous navigation and guidance system for low thrust driven deep space missions

Presented herein is a concept of an Autonomous Navigation & Guidance System for electrically propelled deep space missions, including hardware configuration, algorithms for autonomous navigation and guidance, and estimates of potential guidance precision and mass consumption. This concept is actually a unified Navigation, Guidance and Attitude Control system. The unification is imposed by strong coupling between the orbital motion and the spacecraft attitude characteristic of low thrust space flights. The sensor set of the system consists of an optical instrument (Coupled Sun Star Tracker), and a block of four vector accelerometers. The propulsion subsystem is a set of nearly parallel Hall thrusters rigidly attached to the spacecraft body. The final stage of data processing is combining the thrust and torque programs and generating power and mass rate shares for every thruster. An end-to-end computer simulation provides guidance accuracy estimates versus the navigation data precision, flight time and available maximum thrust. Terminal guidance errors of a few tens of km in position and a few tens of cm/s in velocities are predicted under plausible assumptions on system parameters. Mass expenditures for the control are typically below one percent of total fuel mass budget.     

GPS在航天器编队飞行任务中的基础性作用

GPS正在改变航天器的测控格局 ,拓宽卫星和星座控制技术 ,从而构成空间编队飞行定时、测量和控制的技术基础。国内外已开发出对航天器编队飞行任务进行精确定位和导航的GPS方案。GPS将充当一大类多航天器编队飞行任务的导航系统。在当前开发的空间编队飞行技术中 ,编队航天器的测量和控制、星间链路通信、任务综合与验证、编队飞行试验台、分散式控制、高轨道航天器的相对导航等 ,无一不与GPS息息相关     

光纤陀螺的最新进展

介绍了光纤陀螺 (FOG)的基本原理 ,以及国内外光纤陀螺的最新发展情况。分析了目前普遍采用的几种光纤陀螺技术方案并对光纤陀螺的未来发展状况作了展望     

Ground and on-orbit command and data handling architectures for the Active Rack Isolation System microgravity flight experiment

The Active Rack Isolation System [ARIS] International Space Station [ISS] Characterization Experiment, or ARIS-ICE for short, is a long duration microgravity characterization experiment aboard the ISS. The objective of the experiment is to fully characterize active microgravity performance of the first ARIS rack deployed on the ISS. Efficient ground and on-orbit command and data handling [C&DH] segments are the crux in achieving the challenging objectives of the mission. The objective of the paper is to provide an overview of the C&DH architectures developed for ARIS-ICE, with the view that these architectures may serve as a model for future ISS microgravity payloads. Both ground and on-orbit segments, and their interaction with corresponding ISS C&DH systems are presented. The heart of the on-orbit segment is the ARIS-ICE Payload On-orbit Processor, ARIS-ICE POP for short. The POP manages communication with the ISS C&DH system and other ISS subsystems and payloads, enables automation of test/data collection sequences, and provides a wide range of utilities such as efficient file downlinks/uplinks, data post-processing, data compression and data storage. The hardware and software architecture of the POP is presented and it is shown that the built-in functionality helps to dramatically streamline the efficiency of on-orbit operations. The ground segment has at its heart special ARIS-ICE Ground Support Equipment [GSE] software developed for the experiment. The software enables efficient command and file uplinks, and reconstruction and display of science telemetry packets. The GSE software architecture is discussed along with its interactions with ISS ground C&DH elements. A test sequence example is used to demonstrate the interplay between the ground and on-orbit segments.     

Near-infrared detection of potential evidence for microscopic organisms on Europa

The possibility of an ocean within the icy shell of Jupiter's moon Europa has established that world as a primary candidate in the search for extraterrestrial life within our Solar System. This paper evaluates the potential to detect evidence for microbial life by comparing laboratory studies of terrestrial microorganisms with measurements from the Galileo Near Infrared Imaging Spectrometer (NIMS). If the interior of Europa at one time harbored life, some evidence may remain in the surface materials. Examination of laboratory spectra of terrestrial extremophiles measured at cryogenic temperatures reveals distorted, asymmetric nearinfrared absorption features due to water of hydration. The band centers, widths, and shapes of these features closely match those observed in the Europa spectra. These features are strongest in reddish-brown, disrupted terrains such as linea and chaos regions. Narrow spectral features due to amide bonds in the microbe proteins provide a means of constraining the abundances of such materials using the NIMS data. The NIMS data of disrupted terrains exhibit distorted, asymmetric near-infrared absorption features consistent with the presence of water ice, sulfuric acid octahydrate, hydrated salts, and possibly as much as 0.2 mg cm(-3) of carbonaceous material that could be of biological origin. However, inherent noise in the observations and limitations of spectral sampling must be taken into account when discussing these findings.