Sergio Montenegro

BEESAT: A Pico Satellite for the On Orbit Verification of Micro Wheels

The Technical University of Berlin has the objective to develop such components, which are not available yet. The first device under development is the so called micro wheel, which is designed to be used in pico satellites, allowing a precise 3-axis attitude stabilization. The verification of these wheels in space will be done by BEESAT, the first pico satellite of TU Berlin. The main objective of BeeSat is the on orbit verification of newly developed micro wheels for pico satellite applications. These wheels, with the size of a one Euro coin in diameter, supported by DLR (FKZ 50JR0552) and developed in cooperation with Astro-und Feinwerktechnik, will drastically improve the actuation capabilities of pico satellites.

A customizable and ARINC 653 quasi-compliant hypervisor

This paper presents a novel hypervisor, developed for aerospace applications using an object oriented approach that embodies time and space partitioning (TSP) on a PowerPC (PPC) core embedded in a FPGA, for the NetworkCentric core avionics [1] - an architecture of cooperating components and managed by a real-time operating system, to implement dependable computing and targeting simplicity. To support Integrated Modular Architecture (IMA) [2] partitioned software architectures, the proposed hypervisor adapted to the aerospace application domain the Popek and Goldbergs [3] fidelity, efficiency and resource control virtualization requirements, and extends them with additional ones like timing determinism, reactivity and improved dependability. A distinctive feature of this hypervisor is its I/O device virtualization approach that guarantees real-time performance and small trusted computing base. The object oriented approach will be particularly useful to customize key components of the hypervisor (with different granularity levels) such as partition scheduling and the communications manager using generative programming techniques (Aspect Oriented Programming (AOP) and template meta-programming).

PowerBIRD - modern spacecraft bus controller

The objective of the BIRD satellite project is to evaluate an innovative infrared sensor technlogy for hot-spot detection on the earth. Within the PowerBIRD project GMD FIRST provides the dependable board computer: hardware and software for the BIRD satellite of DLR. This control system was developed as hardware-software co-design using modern technology. Modern technology gave us an order of magnitude more performance over space proved technology without loosing dependability. Redundancy and parallelism was used to get high dependability from not dependable components. An object oriented approach on the operating system and application development provided a very flexible and efficient way to create and configure the system.

Middleware Fault Tolerance Support for the BOSS Embedded Operating System

Critical embedded systems need a dependable operating system and application. Despite all efforts to prevent and remove faults in system development, residual software faults usually persist. Therefore, critical systems need some sort of fault tolerance to deal with these faults and also with hardware faults at operation time. This work proposes fault-tolerant support mechanisms for the BOSS embedded operating system, based on the application of proven fault tolerance strategies by middleware control software which transparently delivers the added functionality to the application software. Special attention is taken to complexity control and resource constraints, targeting the needs of the embedded market.

Flowing Taks: Scalable Software Dependability and Performance

Dependability is a major challenge when designing space computing systems, both at software and hardware level. After 30 years of contentious research on how to achieve high dependability, not a single solution has been found. A huge effort has been invested to improve reliability, using reliable radiation hardened components. However, failures cannot be eliminated totally.

Onboard autonomy and fault protection concept of the BIRD satellite

BIRD (Bi-Spectral Infra-Red Detection) has been demonstrating new technologies since its launch on 22. October, 2001 with the PSLV-C3 from Shar/India successfully into a sun-synchronous low Earth orbit at 560 km. Besides the successful in-orbit test of the detection and evaluation of vegetation fires with micro satellites, BIRD has also been demonstrating a number of advanced spacecraft bus technologies, especially in the field of satellite autonomy and fault detection and protection. A number of ingenious features make it possible to operate the 92 kg satellite in a comfortable and safely way. Special features include the autonomous management of onboard computer failures, surveillance and response to critical parameters limit exceeding, system attitude anomalies. A robust redundancy philosophy and optimised ground-spacecraft interaction concept has contributed to the success of the BIRD mission, which was designed to operate for one year and has completed now its second year of operation. The paper describes the related new technologies and the results from the experience with BIRD.