Towards improved satellite telecommand link availability

Compliant with the Consultative Committee for Space Data Systems (CCSDS) set of protocols, we explore enhancing the availability service for space links. In particular, we consider specific improved defences against jamming attacks affecting symbol synchronization. More robust adaptive closed-loop symbol synchronizers are designated with a view to the planned update of the CCSDS standard for the telecommand synchronization and channel coding sublayer of the data link layer. It is shown that adaptive schemes exploiting instantaneous jammer state information are recommended to counter destructive attacks that may harm the availability

Trust Management and Security in Satellite Telecommand Processing

New standards and initiatives in satellite system architecture are moving the space industry to more open and efficient mission operations. Primarily, these standards allow multiple missions to share standard ground and space based resources to reduce mission development and sustainment costs. With the benefits of these new concepts comes added risk associated with threats to the security of our critical space assets in a contested space and cyberspace domain. As one method to mitigate threats to space missions, this research develops, implements, and tests the Consolidated Trust Management System (CTMS) for satellite flight software. The CTMS architecture was developed using design requirements and features of Trust Management Systems (TMS) presented in the field of distributed information systems. This research advances the state of the art with the CTMS by refining and consolidating existing TMS theory and applying it to satellite systems. The feasibility and performance of this new CTMS architecture is demonstrated with a realistic implementation in satellite flight software and testing in an emulated satellite system environment. The system is tested with known threat modeling techniques and a specific forgery attack abuse case of satellite telecommanding functions. The CTMS test results show the promise of this technique to enhance security in satellite flight software telecommand processing. With this work, a new class of satellite protection mechanisms is established, which addresses the complex security issues facing satellite operations today. This work also fills a critical shortfall in validated security mechanisms for implementation in both public and private sector satellite systems

SUNSAT, Stellenbosch University and SA-AMSAT\u27s Remote Sensing and Packet Communications Microsatellite

The Engineering Model of SUNSAT, a 50 kg, 45 cm, Ariane ASAP-compatible microsatellite is scheduled for assembly in December 1993, permitting flight model completion early in 1995. Fifteen M.Eng. students, led by Computer & Control System lecturers at Stellenbosch University, began detail design in January 1992. Most prototype hardware was operating by July 1993, and assembly of the first final-sized PCB\u27s started. A packet radio service, a 2m parrot speech transponder, and Mode A and S transponders, all defined and endorsed by SA-AMSAT, comprise the Amateur Radio communications payload. Verification of the 15-20 m pixel spacing, 3-color, 3456 pixel pushbroom imager capable of stereo imaging, is a major research goal. Data will be downlinked in S-band, or single images stored in a 64Mbyte RAM. Coarse attitude stabilization by gravity gradient and magnetorquing is improved by small reaction wheels during imaging. Continuous attitude sensing is by magnetometers. Sun sensors, visible band horizon sensors, and star sensor provide 1 mrad accuracy when imaging from the sun-synchronous orbit. Average power of 30 W enables images of South Africa to be taken on a daily basis for real time downlinking. Satisfaction of SA electronics companies on our Advisory Board with the engineering model will lead to continued student funding. Demonstration of a working engineering model will then hopefully provide the credibility we need to finalize a launch opportunity. The satellite\u27s layout, block diagram, and expected performance of the imager, downlink, and Amateur packet communications payload are described

Design of the Electronics Subsystem for a High-Resolution Electro-Optical Payload Using Systems Engineering Approach

Satellite imagers, in contrast to commercial imagers, demand exceptional performance and operate under harsh conditions. The camera is an essential part of an Earth Observation Electro Optical (EO) payload that is designed in response to needs such as military demands, changes in world politics, inception of new technologies, operational requirements and experiments. As one of the key subsystems, the Imager Electronics Subsystem of a high-resolution EO payload plays very important role in the accomplishment of mission objectives and payload goals. Hence, these Electronics Subsystems require a special design approach optimised for their needs and meticulous characterizations of high-resolution space applications. This dissertation puts forward the argument that the system being studied is a subsystem of a larger system and that systems engineering principles can be applied to the subsystem design process also. The aim of this dissertation is to design the Imager Electronics Subsystem of a high-resolution Electro Optical Payload using a systems engineering approach to represent a logical integration and test flow using the space industry guidelines. The Imager Electronics Subsystem consists of group of elements forming the functional chain from the Image Sensors on the Focal Plane down to electrical interface to the Data Handling Unit and power interface of the satellite. This subsystem is responsible for collecting light in different spectral bands, converting this light to data of different spectral bands from image sensors for high-resolution imaging, performing operations for aligning, tagging and multiplexing along with incorporating internal and external interfaces

Third International Symposium on Space Mission Operations and Ground Data Systems, part 2

Under the theme of 'Opportunities in Ground Data Systems for High Efficiency Operations of Space Missions,' the SpaceOps '94 symposium included presentations of more than 150 technical papers spanning five topic areas: Mission Management, Operations, Data Management, System Development, and Systems Engineering. The symposium papers focus on improvements in the efficiency, effectiveness, and quality of data acquisition, ground systems, and mission operations. New technology, methods, and human systems are discussed. Accomplishments are also reported in the application of information systems to improve data retrieval, reporting, and archiving; the management of human factors; the use of telescience and teleoperations; and the design and implementation of logistics support for mission operations. This volume covers expert systems, systems development tools and approaches, and systems engineering issues

AMORE - Mission concept overview for a progressively independent and self-sustainable lunar habitat

Throughout the last decade a renewed interest for lunar space exploration has been expressed through the announcements of many ambitious missions such as Artemis. Annually the Space Station Design Workshop (SSDW) tasks students and young professionals to design a space station concept in a con-current engineering environment. In line with the elevated interest on the Moon this year's SSDW was centred around a self-sustainable lunar habitat. This paper presents the conceptual design of Team Blue at the SSDW 2021. Advanced Moon Operations and Resource Extraction (AMORE) is conceptu-alized as a public-private cooperation for the creation of a lunar platform that acts as an outpost for human exploration and robotic In-situ Resources Utilization (ISRU). AMORE’s proposed location is near the rim of Shackleton Crater at the Lunar South Pole. This location provides opportunities in science and ISRU and favourable sun coverage and thermal conditions. The terrain offers a natural shield for debris and storage advantages for ISRU. The mission architecture allows for incremental crew size increase through a modular dome structure, an initial prioritization of ISRU and a sustainable resource management strategy. Based on the identified system requirements, the initial configuration envisions one core module and two modular structures that would serve as greenhouses or living spaces. The phasing of the base assembly is designed to allow for adequate conditions of an increasing crew size capacity. The greenhouse modules are designed to provide all required oxygen and most required food supply. The modules are constructed using lightweight inflatable structures, while a regolith shell will provide radiation as well as thermal and micrometeorite protection. For reliable communication, a cus-tom relay network named Lunar Earth Telecommand Telemetry Relay (LETTER) is proposed. The mis-sion architecture analysis includes several methods to financially utilize the mission. These include a range of services on the lunar surface such as training facilities for deep space missions, leasing habitats to other Moon explorers, and performing scientific and technological demonstrations. A variety of rovers will be used throughout the mission that will assist in various aspects. In addition to this, a scalable hybrid power generation system that utilizes the abundant sunlight and nuclear energy assures a suffi-cient power supply throughout the entire mission lifetime. This research presents a holistic architecture for a Moon base, which provides an approach to initially utilize the Moon. Within this context, the mission concept is primarily based on already existing or currently in-development technologies. Hence, AMORE offers an approach for a financially and technologically feasible as well as a continuous and expandable human presence on the lunar surfac

A Novel Brainstorming Pedagogy to Mobilize Pico/Nano/Micro-Satellite (PN-MSat) Envineering Research and Education in Indian Academia

The article describes the outcome of activities to positively impact the careers of engineering graduates in India by engaging them in pico/nano/micro-satellite (PNMSat) engineering through a novel brainstorming pedagogy. The pedagogy, derived out of a systems engineering approach developed for the design and development of PNMSat/CubeSat missions, is used to teach a comprehensive course in PNMSat design engineering. The approach involves brainstorming the participants to conceive a PNMSat payload and teach the PNMSat bus design to accommodate the conceived payload. The approach and the comprehensive treatment of the material are the first of their kind in India in the field of small satellite design engineering. The article describes in detail the course contents, the novel approach and the results of the course assessments from three offerings – Summer 2015, Summer 2016 and Summer 2017. It presents the results of surveys conducted to assess the impact on the participants’ awareness in PNMSat engineering, motivation to pursue diverse careers and fulfilling livelihoods. It’s been observed that engineering institutions in India are keen to initiate a PNMSat program but have struggled to do so due to the lack of a systematic approach. The article provides an insight into addressing this problem and mobilizing a PNMSat program at an engineering institution in India

PODIUM:A Pulsar Navigation Unit for Science Missions

PODIUM is a compact spacecraft navigation unit, currently being designed to provide interplanetary missions with autonomous position and velocity estimations. The unit will make use of Pulsar X-ray observations to measure the distance and distance rate from the host spacecraft to the Solar System Barycenter. Such measurements will then be used by the onboard orbit determination function to estimate the complete orbital elements of the spacecraft. The design aims at 6 kg of mass and 20 W of power, in a volume of 150 mm by 240 mm by 600 mm. PODIUM is designed to minimize the impact on the mission operational and accommodation constraints. The architecture is based on a grazing incidence X-ray telescope with focal distance limited to 50 cm. The effective area shall be in the range 25 to 50 cm2 for photon energies in the range 0.2-10 keV, requiring nesting of several mirrors in the Wolter-1 geometry. Grazing incidence angles will be very small, below 2 deg. The current target FOV is 0.25 deg. The pulsars photon arrivals are detected with a single pixel Silicon Drift Detector (SDD) sensor with timing accuracy below 1usec. The unit has no gimbaling to meet the applicable power, size and mass requirements. Instead, the host spacecraft shall slew and point to allow pulsar observation. The avionics architecture is based on a radiation hardened LEON4 processor, to allow a synchronous propagation task and measurement generation and orbit determination step in an asynchronous task. PODIUM will enable higher autonomy and lower cost for interplanetary missions. L2 space observatories and planetary flybys are the current reference use cases. Onboard autonomous state estimation can reduce the ground support effort required for navigation and orbit correction/maintenance computation, and reduce the turnaround time, thus enabling more accurate maneuvers, reducing the orbit maintenance mass budget