SMASS – A Lightweight Satellite Simulation Framework for Concurrent Engineering in Education

The “Satellite Mission Analysis and Simulation System” (SMASS) for small satellites developed at the Technical University Berlin (TU Berlin) is mainly used in the education of aerospace students at universities with the focus on understanding the relations between system parameters [1]. The design of a satellite with SMASS is based on the dynamic simulation of entire mission scenarios, which goes beyond the classical approach of designing and simulating uncoupled subsystems with static dependencies. However, after a detailed analysis of SMASS, it turned out that it is highly recommended to re-engineer SMASS to make it flexible for future extensions. The goal was to develop a new highly modular structure. After an introduction, this paper presents the basic layer structure of the new modular SMASS framework. In the next sections, the different layers are explained. This includes their functions and the connections between them. In the end, an example explains the new feature of comparing different satellite configurations using only one simulation run

Design and operation of a fitted low-cost ground station for remote sensing applications

Natürliche oder vom Menschen verursachte Umweltereignisse und Naturkatastrophen wie große Waldbrände oder Flutkatastrophen beeinflussen immer stärker unser Leben. Der Umgang mit diesen Ereignissen zur Vermeidung von Schäden am Lebensraum und Gesundheit erfordert zunehmend hoch aktuelle Daten, wie sie z.B. von Fernerkundungssatelliten geliefert werden können. Nützlich sind solche Daten in diesen Fällen vor allem dann, wenn sie hoch aktuell sind. Im Rahmen des Satellitenprojektes BIRD wird in dieser Arbeit eine dedizierte low-cost Bodenstation untersucht, mit der es möglich ist, die vom Satelliten empfangenen Daten in nahezu Echtzeit dem Nutzer zur Verfügung zu stellen. Darüber hinaus wird die Möglichkeit zur Kommandierung mit einer low-cost Bodenstation untersucht. Der Darstellung von wesentlichen Grundlagen zur Auslegung solch einer Bodenstation folgt die Beschreibung der hier benutzten Komponenten und deren Beziehungen zueinander. Abschließend werden die Erfahrungen aus dem Betrieb beschrieben.Environmental events, whether natural or caused by humans and natural catastrophes like large wood fires or floods disasters, affect more and more our life. Handling these events in order to avoid damage to the habitats and health requires increasingly highly current data, which can be supplied e.g. by remote sensing satellites. This type of data is, especially useful in the cases given above, if they are highly current. In the context of the satellite project BIRD a dedicated low cost ground station, with which it is possible to give the end-user the satellite data in near real-time after reception from the satellite, is examined in this work. Beyond that, the possibility for commanding the satellite with this low cost ground station examined. The representation of substantial theoretical bases to develop such a ground station is followed by the description of the components used here and their relations. Finally the experiences from the operation of the station are described

Model-based fault detection and diagnosis for spacecraft with an application for the SONATE triple cube nano-satellite

The correct behavior of spacecraft components is the foundation of unhindered mission operation. However, no technical system is free of wear and degradation. A malfunction of one single component might significantly alter the behavior of the whole spacecraft and may even lead to a complete mission failure. Therefore, abnormal component behavior must be detected early in order to be able to perform counter measures. A dedicated fault detection system can be employed, as opposed to classical health monitoring, performed by human operators, to decrease the response time to a malfunction. In this paper, we present a generic model-based diagnosis system, which detects faults by analyzing the spacecraft’s housekeeping data. The observed behavior of the spacecraft components, given by the housekeeping data is compared to their expected behavior, obtained through simulation. Each discrepancy between the observed and the expected behavior of a component generates a so-called symptom. Given the symptoms, the diagnoses are derived by computing sets of components whose malfunction might cause the observed discrepancies. We demonstrate the applicability of the diagnosis system by using modified housekeeping data of the qualification model of an actual spacecraft and outline the advantages and drawbacks of our approach

VELEX: Venus Lightning Experiment

Lightning has fascinated humanity since the beginning of our existence. Different types of lightning like sprites and blue jets were discovered, and many more are theorized. However, it is very likely that these phenomena are not exclusive to our home planet. Venus’s dense and active atmosphere is a place where lightning is to be expected. Missions like Venera, Pioneer, and Galileo have carried instruments to measure electromagnetic activity. These measurements have indeed delivered results. However, these results are not clear. They could be explained by other effects like cosmic rays, plasma noise, or spacecraft noise. Furthermore, these lightning seem different from those we know from our home planet. In order to tackle these issues, a different approach to measurement is proposed. When multiple devices in different spacecraft or locations can measure the same atmospheric discharge, most other explanations become increasingly less likely. Thus, the suggested instrument and method of VELEX incorporates multiple spacecraft. With this approach, the question about the existence of lightning on Venus could be settled

MAPLE: Marsian Autorotation Probe Lander Experiment

The first step towards aerial planetary exploration has been made. Ingenuity shows extremely promising results, and new missions are already underway. Rotorcraft are capable of flight. This capability could be utilized to support the last stages of Entry, Descent, and Landing. Thus, mass and complexity could be scaled down. Autorotation is one method of descent. It describes unpowered descent and landing, typically performed by helicopters in case of an engine failure. MAPLE is suggested to test these procedures and understand autorotation on other planets. In this series of experiments, the Ingenuity helicopter is utilized. Ingenuity would autorotate a ”mid-air-landing” before continuing with normal flight. Ultimately, the collected data shall help to understand autorotation on Mars and its utilization for interplanetary exploration

TechnoSat - A Nanosatellite Mission for On-Orbit Technology Demonstration

In the last 25 years, TU Berlin developed, built, launched and operated a number of university class satellites. Throughout these missions, emphasis was placed on developing technologies for Earth remote sensing, communication and attitude determination and control. The nanosatellite mission TechnoSat has the primary objective to provide on-orbit demonstration capability for novel nanosatellite technologies and components. The satellite carries five main payloads: A separation system for nanosatellites, a hatch mechanism designed for protection and on-orbit calibration of infrared cameras, a fluid dynamic actuator for energy efficient attitude control, an extendable boom system that is employed for gravity gradient stabilisation and STELLA, a miniaturised star tracker. The secondary mission objective of TechnoSat is the on-orbit verification of the novel adaptive nanosatellite bus TUBiX20 (TU Berlin innovative neXt generation 20 kg nanosatellite bus). TechnoSat is scheduled to be launched in Q4 2014

Technology demonstration by the BIRD-mission

Small satellites have to meet a big challenge: to answer high-performance requirements by means of small equipment and especially of small budgets. Out of all aspects the cost aspect is one of the most important driver for small satellite missions. To keep the costs within the low-budget frame (in comparison to big missions) the demonstration of new and not space-qualified technologies for the spacecraft is one key point in fulfilling high-performance mission requirements. Taking this into account the German DLR micro-satellite mission BIRD (Bi-spectral Infra-Red Detection) has to demonstrate a high performance capability of spacecraft bus by using and testing new technologies basing on a mixed parts and components qualification level. The basic approach for accomplishing high-performance capability for scientific mission objectives under low-budget constraints is characterized by using state-of-the-art technologies, a mixed strategy in the definition of the quality level of the EEE parts and components, a tailored quality management system according to ISO 9000 and ECSS, a risk management system, extensive redundancy strategies, extensive tests especially on system level, large designs margins (over-design), robust design principles. The BIRD-mission is dedicated to the remote sensing of hot spot events like vegetation fires, coal seam fires or active volcanoes from space and to the space demonstration of new technologies. For these objectives a lot of new small satellite technologies and a new generation of cooled infrared array sensors suitable for small satellite missions are developed to fulfil the high scientific requirements of the mission. Some basic features of the BIRD spacecraft bus are compact micro satellite structure with high mechanical stability and stiffness, envelope qualification for several launchers, cubic shape in launch configuration with dimensions of about 620 × 620 × 550mm3 and variable launcher interface, mass ratio bus: payload = 62 kg:30 kg, high peak power of 200W at 10–20 min, and average power 60W, advanced thermal control system with radiators, heat pipes, MLI, temperature sensors and contingency heaters, new developed high-performance spacecraft bus computer with integrated latch-up protection and error detection and correction system, three-axis stabilization of the spacecraft by an attitude control system in state space representation, integrating the payload platform with its structure, thermal and power requirements, onboard determination of the spacecraft position and velocity by the onboard navigation system basing on receiving and onboard processing of GPS data, S-band communication with high bit rate (2.2 Mbps) and low bit rate. The total mass of the complete spacecraft is 92 kg. BIRD shall demonstrate the limits and the advantages of using new developed components, methods, algorithms and technologies. The satellite was launched with the Indian PSLV-C3 from Shar on 22nd October 2001 into an Sun-synchronous circular orbit of an altitude of about 568 km. (The paper describes the new developed technologies like onboard navigation system, the high-performance failure tolerant spacecraft computer, the precision reaction wheels, the star sensor, the attitude control system, the onboard classification experiment and the results and flight experience up to now.