Self-supporting CVD diamond charge state conversion surfaces for high resolution imaging of low-energy neutral atoms in space plasmas

Two polycrystalline diamond surfaces, manufactured by chemical vapour deposition (CVD) technique, are investigated regarding their applicability as charge state conversion surfaces (CS) for use in a low energy neutral atom imaging instrument in space research. The capability of the surfaces for converting neutral atoms into negative ions via surface ionisation processes was measured for hydrogen and oxygen with particle energies in the range from 100 eV to 1 keV and for angles of incidence between 6 deg and 15 deg. We observed surface charging during the surface ionisation processes for one of the CVD samples due to low electrical conductivity of the material. Measurements on the other CVD diamond sample resulted in ionisation efficiencies of ~2 % for H and up to 12 % for O. Analysis of the angular scattering revealed very narrow and almost circular scattering distributions. Comparison of the results with the data of the CS of the IBEX-Lo sensor shows that CVD diamond has great potential as CS material for future space missions.

Development of the gas chromatograph – mass spectrometer to investigate volatile species in the lunar soil for the Luna-Resurs mission

Since the analysis of the lunar rocks and soil samples, brought to Earth by the Apollo missions, it is believed that the Moon has a waterless nature and also other volatile species are strongly depleted. Advancement in analysis techniques helped to identify water and other volatile species in lunar volcanic glasses. Additionally, recent lunar space missions detected water and volatile organic compounds in the region of the lunar poles where permanently shadowed craters are existing. All known lunar soil samples available on Earth come from the lunar near side, close to the equator. To verify the most recent measurement results and to enhance the knowledge of the geological history of the Moon it is of high interest to perform in situ measurements on the lunar poles. For this reason the Russian space agency, Roskosmos, developed aprogram for the scientific exploration of the lunar poles. The Gas Analysis Package (GAP) is part of the selected scientific payload aboard the Luna-Resurs Lander. This instrument uses pyrolytic cells and will apply laser spectroscopy, gas chromatography and mass spectrometry to detect and analyze volatile components trapped in the lunar soil. An existing ion optical design of a compact reflectron type time-of-flight mass spectrometer, originally built for the MEAP/P-BACE balloon mission, was chosen as a part of the GAP instrument. The scope of this thesis is the development of the interface between gas chromatography (GC) and this Neutral Gas Mass Spectrometer (NGMS) to perform coupled GC-MS measurements. In the first part of this thesis the interfacing concept was developed and verified by coupling the NGMS prototype to gas chromatography. The second part of this thesis is devoted to the development of the NGMS flight version.

A system design for space-based space surveillance

This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro- satellite platform. The results have been produced in the frame of ESA’s "As sessment Study for Space Based Space Surveillance Demonstration Mission (Phase A) " performed by the Airbus DS consortium. Space Surveillance and Tracking is part of Space Situational Awareness (SSA) and covers the detection, tracking and cataloguing of spa ce debris and satellites. Derived SST services comprise a catalogue of these man-made objects, collision warning, detection and characterisation of in-orbit fragmentations, sub-catalogue debris characterisation, etc. The assessment of SBSS in an SST system architecture has shown that both an operational SBSS and also already a well - designed space-based demonstrator can provide substantial performance in terms of surveillance and tracking of beyond - LEO objects. Especially the early deployment of a demonstrator, possible by using standard equipment, could boost initial operating capability and create a self-maintained object catalogue. Unlike classical technology demonstration missions, the primary goal is the demonstration and optimisation of the functional elements in a complex end-to-end chain (mission planning, observation strategies, data acquisition, processing and fusion, etc.) until the final products can be offered to the users. The presented SBSS system concept takes the ESA SST System Requirements (derived within the ESA SSA Preparatory Program) into account and aims at fulfilling some of the SST core requirements in a stand-alone manner. The evaluation of the concept has shown that an according solution can be implemented with low technological effort and risk. The paper presents details of the system concept, candidate micro - satellite platforms, the observation strategy and the results of performance simulations for GEO coverage and cataloguing accuracy

Space-based space surveillance and tracking demonstrator: mission and system design

This paper presents the capabilities of a Space-Based Space Surveillance (SBSS) demonstration mission for Space Surveillance and Tracking (SST) based on a micro-satellite platform. The results have been produced in the frame of ESA’s "Assessment Study for Space Based Space Surveillance Demonstration Mission" performed by the Airbus Defence and Space consortium. The assessment of SBSS in an SST system architecture has shown that both an operational SBSS and also already a well- designed space-based demonstrator can provide substantial performance in terms of surveillance and tracking of beyond-LEO objects. Especially the early deployment of a demonstrator, possible by using standard equipment, could boost initial operating capability and create a self-maintained object catalogue. Furthermore, unique statistical information about small-size LEO debris (mm size) can be collected in-situ. Unlike classical technology demonstration missions, the primary goal is the demonstration and optimisation of the functional elements in a complex end-to-end chain (mission planning, observation strategies, data acquisition, processing, etc.) until the final products can be offered to the users and with low technological effort and risk. The SBSS system concept takes the ESA SST System Requirements into account and aims at fulfilling SST core requirements in a stand-alone manner. Additionally, requirements for detection and characterisation of small-sizedLEO debris are considered. The paper presents details of the system concept, candidate micro-satellite platforms, the instrument design and the operational modes. Note that the detailed results of performance simulations for space debris coverage and cataloguing accuracy are presented in a separate paper “Capability of a Space-based Space Surveillance System to Detect and Track Objects in GEO, MEO and LEO Orbits” by J. Silha (AIUB) et al., IAC-14, A6, 1.1x25640.

Space debris attitude simulation - ιOTA (In-Orbit Tumbling Analysis)

Today, there is little knowledge on the attitude state of decommissioned intact objects in Earth orbit. Observational means have advanced in the past years, but are still limited with respect to an accurate estimate of motion vector orientations and magnitude. Especially for the preparation of Active Debris Removal (ADR) missions as planned by ESA’s Clean Space initiative or contingency scenarios for ESA spacecraft like ENVISAT, such knowledge is needed. ESA's “Debris Attitude Motion Measurements and Modelling” project (ESA Contract No. 40000112447), led by the Astronomical Institute of the University of Bern (AIUB), addresses this problem. The goal of the project is to achieve a good understanding of the attitude evolution and the considerable internal and external effects which occur. To characterize the attitude state of selected targets in LEO and GTO, multiple observation methods are combined. Optical observations are carried out by AIUB, Satellite Laser Ranging (SLR) is performed by the Space Research Institute of the Austrian Academy of Sciences (IWF) and radar measurements and signal level determination are provided by the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR). The In-Orbit Tumbling Analysis tool (ιOTA) is a prototype software, currently in development by Hyperschall Technologie Göttingen GmbH (HTG) within the framework of the project. ιOTA will be a highly modular software tool to perform short-(days), medium-(months) and long-term (years) propagation of the orbit and attitude motion (six degrees-of-freedom) of spacecraft in Earth orbit. The simulation takes into account all relevant acting forces and torques, including aerodynamic drag, solar radiation pressure, gravitational influences of Earth, Sun and Moon, eddy current damping, impulse and momentum transfer from space debris or micro meteoroid impact, as well as the optional definition of particular spacecraft specific influences like tank sloshing, reaction wheel behaviour, magnetic torquer activity and thruster firing. The purpose of ιOTA is to provide high accuracy short-term simulations to support observers and potential ADR missions, as well as medium-and long-term simulations to study the significance of the particular internal and external influences on the attitude, especially damping factors and momentum transfer. The simulation will also enable the investigation of the altitude dependency of the particular external influences. ιOTA's post-processing modules will generate synthetic measurements for observers and for software validation. The validation of the software will be done by cross-calibration with observations and measurements acquired by the project partners.