Low cost planetary exploration: surrey lunar minisatellite and interplanetary platform missions

In order to meet the growing global requirement for affordable missions beyond Low Earth Orbit, two types of platform are under design at the Surrey Space Centre. The first platform is a derivative of Surrey's UoSAT-12 minisatellite, launched in April 1999 and operating successfully in-orbit. The minisatellite has been modified to accommodate a propulsion system capable of delivering up to 1700 m/s delta-V, enabling it to support a wide range of very low cost missions to LaGrange points, Near-Earth Objects, and the Moon. A mission to the Moon - dubbed “MoonShine” - is proposed as the first demonstration of the modified minisatellite beyond LEO. The second platform - Surrey's Interplanetary Platform - has been designed to support missions with delta-V requirements up to 3200 m/s, making it ideal for low cost missions to Mars and Venus, as well as Near Earth Objects (NEOs) and other interplanetary trajectories. Analysis has proved mission feasibility, identifying key challenges in both missions for developing cost-effective techniques for: spacecraft propulsion; navigation; autonomous operations; and a reliable safe mode strategy. To reduce mission risk, inherently failure resistant lunar and interplanetary trajectories are under study. In order to significantly reduce cost and increase reliability, both platforms can communicate with low-cost ground stations and exploit Surrey's experience in autonomous operations. The lunar minisatellite can provide up to 70 kg payload margin in lunar orbit for a total mission cost US$16–25 M. The interplanetary platform can deliver 20 kg of scientific payload to Mars or Venus orbit for a mission cost US$25–50 M. Together, the platforms will enable regular flight of payloads to the Moon and interplanetary space at unprecedented low cost. This paper outlines key systems engineering issues for the proposed Lunar Minisatellite and interplanetary Platform Missions, and describes the accommodation and performance offered to planetary payloads.     

Earth observation using low cost micro/minisatellites

Surrey Satellite Technology Ltd (SSTL) at the University of Surrey (UK) has pioneered cost-effective satellite engineering techniques for smaller, faster, cheaper satellites to provide affordable access to space. SSTL has designed, built, launched and operated a series of twelve 50kg microsatellites in low Earth orbit which carry a wide range of satellite communications, space science, remote sensing and in-orbit technology demonstration payloads — for both civil and military applications. Each of these has been built and launched for around US$3M. This paper reviews SSTL's remote sensing capabilities and presents image results from the microsatellite cameras in low Earth in orbit. The latest microsatellites (TMSAT & FASat-Bravo) under construction at SSTL and due for launch in mid-1997 will provide 3-band multispectral imaging with 80-metre resolution; autonomous on-board image analysis, processing and compression prior to transmission direct to ground-based users employing small portable terminals.     

A systems engineering environment for integrated satellite development

Space mission implementation faces a very dynamic environment with fast-paced information technology advancement and shrinking space budgets. A more focused use of decreasing public investments in space requires a cost reduction over their entire life cycle, up to the end of the useful life of a spacecraft. The anticipation of cost, schedule, risk and performance requirements from all over the product life cycle to the early stages of product development is generally recognised as a necessary condition to reduce life cycle cost. In order to cope with the intrinsic functional complexity of space products, such requirements engineering activity must be performed in a structured way within a systems engineering approach. This paper aims to describe how Cradle, a commercial systems engineering environment software package, can be used for integrated satellite development, taking into consideration functional and life cycle process requirements. Cradle has requirements management, system modelling, performance modelling, configuration management and document generation capabilities integrated in the same environment. Also, the paper provides some examples of application and highlights how Cradle can enhance the satellite development related activities performed by the Brazilian Institute for Space Research (INPE).     

Space WARC-85: much left undone

Dr Martinez reports here on the ITU Space WARC-85 conference, Geneva, August–September 1985. This report outlines the salient decisions of the conference and considers their implications for the Conference's second session in 1988.     

A note on China's space technology

Since the early 1960s China has been making its own contribution to space exploration. This note outlines China's plans for building a space station and developing an Earth-space transporation system in the 1990s.