With regard to the subsequent missions the Flying Laptop will evaluate new technologies.

Topics of special interest are:

The Flying Laptop will use a fully processor-less primary on-board computer (OBC) consisting of field programmable gate arrays (FPGAs) as an innovative technology to be tested in space.
The OBC is based on a Xilinx Vertex-II Pro with approx. 3 million system gates and a clock frequency of 200MHz. Further, the OBC will consist of 4 MB of synchronous static RAM for high speed data processing, 2 x 128 MB DDR RAM and 1 GB Flash. Via a modem, a user programmable EEPROM can be reconfigured from the ground station. In case of failure, the original FPGA configuration is restored from a PROM.
With a software-to-hardware compiler it is possible to directly generate the logical configuration of FPGA gates from a C-like high level language without producing the machine code for a processor. Thus massive parallel processing is possible. To make the system fault-tolerant and to address radiation issues, four equal independent nodes will work together. Depending on the state of the system 1-4 nodes will run at the same time and are dynamically switched on or off, with a complete start-up of a single node takes only 10ms.
The OBC system is currently under development by the Steinbeis Transferzentrum Raumfahrt in cooperation with the Fraunhofer Institute for Computer Architecture and Software Technology.

The Ka-band frequency range is necessary to allow self-controlled communication for the planned lunar mission. A required dish size of 30 m for communication in a lower frequency range is obviously impossible at the roof of the university. Thus using a higher frequency communication in the Ka-band a dish with 3 m diameter is sufficient. The procurement of a Ka-band dish is in preparation.
As payload the Flying Laptop will be equipped with a Ka-band traveling wave tube (TWT) amplifier. During a ground station fly-over, the TWT will operate with an RF transmission power of 57 W (170.5 W DC input) which is unique for a micro-satellite. With this subsystem a data rate of 100 Mbit/s is being sought. The satellite's cassegrain system with its 50 cm primary dish provides the antenna reflector for the Ka-band communication and is also used as the optical system for the thermal infrared camera. The TWT is the design driver for the battery system to handle its high power requirement.

In cooperation with RWE Space Solar Power and EADS Astrium the three solar panels of the Flying Laptop will be equipped with triple-junction solar cells having an efficiency of approx. 26%. A new associated manufacturing process for bonding the cells to the sandwich panel is subject to be qualified during the flight.
Furthermore the Flying Laptop will be the on-orbit testbed for the new generation of penta-junction solar cells with an efficiency higher than 30%. These cells are only used for demonstration and not for energy supply and will be mounted on the side panels.

The attitude control system needs to provide the selected earth observation instruments with a high pointing accuracy of 2.5 arcseconds as well as agile maneuvering capabilities which is a big challenge for a micro-satellite. This can only be achieved by a thorough control concept and high performance sensors/actuators.
By using the FPGA on-board computer a significant advantage in terms of parallelization of the system is achieved. New methods in implementing the attitude contol algoritms are presently being pursued.

Selected sensors and actuators for the ACS

GENIUS the "GPS Enhanced NavIgation system for the University of Stuttgart micro-satellite" is an experiment being conducted in cooperation with the German Space Operations Center (DLR/GSOC). The antennas of three separate GPS receivers will be placed on three corners of the body-mounted central solar array in an L-like arrangement.
For onboard usage GENIUS offers real-time position, velocity and timing information with envisaged accuracies of 10 m, 0.1 m/s and 1 µs. As a novelty, all receivers can be driven by an oven controlled crystal oscillator that provides an ultra-stable reference frequency onboard the Flying Laptop. Furthermore raw code and carrier measurements will be recorded and dumped during ground station contacts for offline analysis. For this case, an orbit determination accuracy of down to 1m can be achieved using extended GPS data arcs. In addition, it will be possible to determine the spacecraft attitude from GPS carrier phase measurements with an accuracy of 0.1° to 1°.

Placement of the three GPS antennas

GPS receiver board

The high flexibility of the FPGA on-board computer (OBC) system will be used to operate the Flying Laptop in a so-called Rent-A-Sat mode. Meaning, that it is possible to configure the system for customer preferences (i.e. the characteristics of a certain processor can be simulated through the hardware). With this versatility the system is well suited for OBC software or component firmware validation in space. A control software running in the background provides the satellite from mis-handling through users, e.g. pointing the cameras towards the sun. In this case the default Flying Laptop software takes control over the satellite.