Optical and Quasi-Optical Design and Analysis of Astronomical Instrumentation including a Prototype SAFARI Pixel

The work of this thesis focuses primarily on the quasi-optical analysis of optical systems in the Terahertz region of the spectrum. This included the development of novel simulation techniques based on the principles of mode matching and gaussian beam mode analysis, which are uniquely suited to the simulation of electrically large optical systems at millimeter wavelengths. Additionally, several commercial software packages were used and experimental measurements conducted for the purpose of both validating the newly developed simulation techniques, as well as simulating / measuring specific elements beyond the scope of the in-house software. The main drivers behind this work were a Technology Research Programme of the European Space Agency, the optical payload design of the future proposed Space Infrared-Telescope for Cosmology and Astrophysics mission and work on the Atacama Large Millimeter Array. Once the simulation tools were developed and proven an analysis of these optical systems was conducted. In the case of the Atacama Large Millimeter Array this involved the analysis of the proposed system, whilst for the other projects of the European Space Agency, although an initial optical system was proposed, much work was also required in maturing the design as well as conducting a standard analysis. This was carried out in conjunction with the other groups of the Technology Research Programme, which included the Terahertz optics group of NUI-Maynooth, the Space Research Organisation of the Netherlands, Rutherford Appleton Laboratory Space, and work groups of the universities of Cambridge and Cardiff. The work of this thesis also considered the technical feasibility and design of a future space mission for the purpose of characterising Earth-type exoplanets up to 30 pc distant. This involved the establishment of the science goals and the associated technical requirements, as well as a detailed optical design of the proposed spectropolarimetric payload

Exploration of the Trade Space Between Unmanned Aircraft Systems Descent Maneuver Performance and Sense-and-Avoid System Performance Requirements

A need exists to safely integrate Unmanned Aircraft Systems (UAS) into the United States' National Airspace System. Replacing manned aircraft's see-and-avoid capability in the absence of an onboard pilot is one of the key challenges associated with safe integration. Sense-and-avoid (SAA) systems will have to achieve yet-to-be-determined required separation distances for a wide range of encounters. They will also need to account for the maneuver performance of the UAS they are paired with. The work described in this paper is aimed at developing an understanding of the trade space between UAS maneuver performance and SAA system performance requirements, focusing on a descent avoidance maneuver. An assessment of current manned and unmanned aircraft performance was used to establish potential UAS performance test matrix bounds. Then, near-term UAS integration work was used to narrow down the scope. A simulator was developed with sufficient fidelity to assess SAA system performance requirements. The simulator generates closest-point-of-approach (CPA) data from the wide range of UAS performance models maneuvering against a single intruder with various encounter geometries. Initial attempts to model the results made it clear that developing maneuver performance groups is required. Discussion of the performance groups developed and how to know in which group an aircraft belongs for a given flight condition and encounter is included. The groups are airplane, flight condition, and encounter specific, rather than airplane-only specific. Results and methodology for developing UAS maneuver performance requirements are presented for a descent avoidance maneuver. Results for the descent maneuver indicate that a minimum specific excess power magnitude can assure a minimum CPA for a given time-to-go prediction. However, smaller amounts of specific excess power may achieve or exceed the same CPA if the UAS has sufficient speed to trade for altitude. The results of this study will support UAS maneuver performance requirements development for integrating UAS in the NAS. The methods described are being used to help RTCA Special Committee 228 develop requirements

CUSTARD (Cranfield University Space Technology Advanced Research Demonstrator) - A Micro-System Technology Demonstrator Nanosatellite. Summary of the Group Design Project MSc in Astronautics and Space Engineering. 1999-2000, Cranfield University

CUSTARD (Cranfield University Space Technology And Research Demonstrator) was the group design project for students of the MSc in Astronautics and Space Engineering for the Academic Year 1999/2000 at Cranfield University. The project involved the initial design of a nanosatellite to be used as a technology demonstrator for microsystem technology (MST) in space. The students worked together as one group (organised into several subgroups, e.g. system, mechanical), with each student responsible for a set of work packages. The nanosatellite designed had a mass of 4 kg, lifetime of 3 months in low Earth orbit, coarse 3-axis attitude control (no orbit control), and was capable of carrying up to 1 kg of payload. The electrical power available was 18 W (peak). Assuming a single X-band ground station at RAL (UK), a data rate of up to 1 M bit s-1 for about 3000 s per day is possible. The payloads proposed are a microgravity laboratory and a formation flying experiment. The report summarises the results of the project and includes executive summaries from all team members. Further information and summaries of the full reports are available from the College of Aeronautics, Cranfield University