Conceptual design analysis for a two-stage-to-orbit semi-reusable launch system for small satellites

This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system employs a multi-stage vehicle powered by rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject 500 kg of payload into low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies and on the commercial potential of the technical design. The vehicle design is analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs. Results from two trade-off studies are shown, evaluating the choice wing area and thus aerodynamic characteristics, and the choice of stage masses and engines selection on the mission performance

ECOSSE: Estimating Carbon in Organic Soils - Sequestration and Emissions: Final Report

Background Climate change, caused by greenhouse gas ( GHG) emissions, is one of the most serious threats facing our planet, and is of concern at both UK and devolved administration levels. Accurate predictions for the effects of changes in climate and land use on GHG emissions are vital for informing land use policy. Models which are currently used to predict differences in soil carbon (C) and nitrogen (N) caused by these changes, have been derived from those based on mineral soils or deep peat. None of these models is entirely satisfactory for describing what happens to organic soils following land-use change. Reports of Scottish GHG emissions have revealed that approximately 15% of Scotland's total emissions come from land use changes on Scotland's high carbon soils; the figure is much lower for Wales. It is therefore important to reduce the major uncertainty in assessing the carbon store and flux from land use change on organic soils, especially those which are too shallow to be deep peats but still contain a large reserve of C. In order to predict the response of organic soils to external change we need to develop a model that reflects more accurately the conditions of these soils. The development of a model for organic soils will help to provide more accurate values of net change to soil C and N in response to changes in land use and climate and may be used to inform reporting to UKGHG inventories. Whilst a few models have been developed to describe deep peat formation and turnover, none have so far been developed suitable for examining the impacts of land-use and climate change on the types of organic soils often subject to land-use change in Scotland and Wales. Organic soils subject to land-use change are often (but not exclusively) characterised by a shallower organic horizon than deep peats (e.g. organo-mineral soils such as peaty podzols and peaty gleys). The main aim of the model developed in this project was to simulate the impacts of land-use and climate change in these types of soils. The model is, a) be driven by commonly available meteorological data and soil descriptions, b) able to simulate and predict C and N turnover in organic soils, c) able to predict the impacts of land-use change and climate change on C and N stores in organic soils in Scotland and Wales. In addition to developing the model, we have undertaken a number of other modelling exercises, literature searches, desk studies, data base exercises, and experimentation to answer a range of other questions associated with the responses of organic soils in Scotland and Wales to climate and land-use change. Aims of the ECOSSE project The aims of the study were: To develop a new model of C and N dynamics that reflects conditions in organic soils in Scotland and Wales and predicts their likely responses to external factors To identify the extent of soils that can be considered organic in Scotland and Wales and provide an estimate of the carbon contained within them To predict the contribution of CO 2, nitrous oxide and methane emissions from organic soils in Scotland and Wales, and provide advice on how changes in land use and climate will affect the C and N balance In order to fulfil these aims, the project was broken down into modules based on these objectives and the report uses that structure. The first aim is covered by module 2, the second aim by module 1, and the third aim by modules 3 to 8. Many of the modules are inter-linked. Objectives of the ECOSSE project The main objectives of the project were to: Describe the distribution of organic soils in Scotland and Wales and provide an estimate of the C contained in them Develop a model to simulate C and N cycling in organic soils and provide predictions as to how they will respond to land-use, management and climate change using elements of existing peat, mineral and forest soil models Provide predictive statements on the effects of land-use and climate change on organic soils and the relationships to GHG emissions, including CO 2, nitrous oxide and methane. Provide predictions on the effects of land use change and climate change on the release of Dissolved Organic Matter from organic soils Provide estimates of C loss from scenarios of accelerated erosion of organic soils Suggest best options for mitigating C and N loss from organic soils Provide guidelines on the likely effects of changing land-use from grazing or semi-natural vegetation to forestry on C and N in organic soils Use the land-use change data derived from the Countryside Surveys of Scotland and Wales to provide predictive estimates for changes to C and N balance in organic soils over time

Vehicle and mission design of a future small payload launcher

This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject a 500 kg payload in different low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies. The vehicle design are analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs

A commercially driven design approach to UK future small payload launch systems

Miniaturisation of satellite componentry, increasingly capable small sensors and substantial increases in processing capacity and transmission bandwidth are driving rapid growth in small payload development and consequential launch demand. The advent of horizontal take-off spaceports opens the door for a new generation of small payload launch systems that will fulfil this demand. However, the key to a launch system's success is its ability to provide a return on the substantial costs of development while delivering pricing levels commensurate with the needs of launch customers. Therefore, commercially led design approaches are needed to refine and optimise the design of the new small payload launch systems required. This approach was embodied in an ongoing UKSA funded NSTP2 project titled Future UK Small Payload Launcher (FSPLUK). The approach is first founded upon a bespoke and specific market assessment. This characterises, segments and quantifies the commercial opportunity and establishes principal desired system performance requirements. An assessment of available technologies at differing TRLs permits initial vehicle configuration options to be developed and technically assessed. Technically viable options are then assessed in terms of commercial viability with the best advanced into more detailed technical assessment and system optimisation. The resultant vehicles are again tested for commercial viability and, if successful, emerge as recommended development avenues. Using these methods, it has been possible to iterate design concepts from apparently simple yet economically sub-optimised stacked launcher systems through several design iterations to a resultant highly flexible and economically efficient conceptual design. The key finding relates to the inter-relationship between payload flexibility, in permitting maximised flight rates from a reasonably complex but highly reusable first stage design, and low disposable upper stage unit cost. This has driven the resultant system to feature an air launched integrated re-usable first stage vehicle, configured with a flexible internal payload bay from which one or more upper stages are deployed. This configuration maximises commercial utility and reusability. The resultant high flight rate allows development costs to be efficiently amortised with minimised direct launch costs. The configuration therefore meets low cost per kg price targets while delivering a positive return on development expenditure over life. It also provides a flight proven vehicle platform with available internal real-estate for application as a hypersonic air test platform for new propulsion systems, such as SABRE. The commercially led approach has created the foundation for viable and economically justifiable development

How to launch small payloads? Evaluation of current and future small payload launch systems

This paper describes a preferable vehicle classification alongside a brief description of key technologies available on the shelf or under development to address the demand of the small payload market. This is followed by a discussion on the investigation of the current market and the future forecast; regarding the delivery of small payloads into orbit

Conceptual design analysis for a two-stage-to-orbit semi-reusable launch system for small satellites

This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject 500 kg payload in different low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies. The vehicle design are analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs. Results from two trade-offs studies are shown, evaluating the choice wing area and thus aerodynamic characteristics, and the choice of stage masses and engines selection on the mission performance

Removing the Threat of Diclofenac to Critically Endangered Asian Vultures

Veterinary use of the nonsteroidal anti-inflammatory (NSAID) drug diclofenac in South Asia has resulted in the collapse of populations of three vulture species of the genusGyps to the most severe category of global extinction risk. Vultures are exposed to diclofenac when scavenging on livestock treated with the drug shortly before death. Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. Concern about this issue led the Indian Government to announce its intention to ban the veterinary use of diclofenac by September 2005. Implementation of a ban is still in progress late in 2005, and to facilitate this we sought potential alternative NSAIDs by obtaining information from captive bird collections worldwide. We found that the NSAID meloxicam had been administered to 35 captiveGyps vultures with no apparent ill effects. We then undertook a phased programme of safety testing of meloxicam on the African white-backed vultureGyps africanus, which we had previously established to be as susceptible to diclofenac poisoning as the endangered AsianGyps vultures. We estimated the likely maximum level of exposure (MLE) of wild vultures and dosed birds by gavage (oral administration) with increasing quantities of the drug until the likely MLE was exceeded in a sample of 40G. africanus. Subsequently, sixG. africanus were fed tissues from cattle which had been treated with a higher than standard veterinary course of meloxicam prior to death. In the final phase, ten Asian vultures of two of the endangered species(Gyps bengalensis,Gyps indicus) were dosed with meloxicam by gavage; five of them at more than the likely MLE dosage. All meloxicam-treated birds survived all treatments, and none suffered any obvious clinical effects. Serum uric acid concentrations remained within the normal limits throughout, and were significantly lower than those from birds treated with diclofenac in other studies. We conclude that meloxicam is of low toxicity toGyps vultures and that its use in place of diclofenac would reduce vulture mortality substantially in the Indian subcontinent. Meloxicam is already available for veterinary use in India