The future of launch vehicles

This article traces the development of satellite launch vehicles from the derivatives of long-range ballistic missiles to the current Ariane and Space Shuttle programmes. Looking to the next generation of launchers, the author outlines current thinking on reusable vehicles, focusing particularly on the British Aerospace/Rolls Royce HOTOL concept.     

未来大规模低成本进入空间路径研究（英文）

The objective of this study is to identify the requirements of access to space for the future, the required methodology, key technologies and international cooperation mode. Firstly, the mission requirements and the challenges of current technologies to access to space are analyzed and summarized. The solutions and related key technologies to realize large-scale and low-cost access to space(L2 AS) are presented here, including the low-cost design of expendable launch vehicles and a reusable space transportation system, interface standardization, and new conceptual launchers. The mission modes based on launch vehicles to realize L2 AS and three future international collaboration modes are presented. Lastly, the relevant conclusions and suggestions are given.     

The overredundant spacecraft—A competitive approach to future telecommunication satellites

Present operational space telecommunication systems are based on simultaneous availability of more than one satellite on orbit, mainly a spare satellite in addition to the operational one.Considering the costs associated to the delivery of extra flight models and to extra launchers, the question is asked whether it would not be advantageous to launch a very limited number of “overredundant” spacecraft instead of several standard satellites.The paper gives main conditions of reliability, size and redundancy concept under which an “overredundant” spacecraft could be a competitive approach to future operational systems.     

Space optical payloads, new application area for high temperature composites

High temperature composites have been extensively developed in order to produce thermal protection systems of reusable re-entry vehicles and launchers. This development effort covers all aspects including sizing, design, manufacturing processes characterization, non destructive inspection, and all industrial facilities which have also been installed. Strong interest recently appeared for these materials to meet requirements for different space applications. In particularly, for more stringent optical payloads, new materials with high performance requirements have appeared. In the field of high dimensionally stable structures for telescopes, materials have to meet severe requirements, such as low coefficients of thermal expansion, good specific modulus, long-term stability (moisture and chemical insensitivity), etc. Carbon/carbon (C/C) composites can meet these specifications. To demonstrate this capability a structure has been designed, manufactured and will be submitted for complete testing (work supported by ESA/ESTEC). The main available results (part feasibility, characterizations, analysis and stability performance budgets) are presented. For future telescope mirrors, silicon carbide is already known as a good candidate. However, an innovative concept based on silicon carbide sandwich honeycomb technology, which allows optimized design, has been developed. The first characterization results and manufacturing capabilities are presented.     

Solar Probe Mission with Multiple Gravity-Assist Maneuvers Realized with Conversion Launchers

The trajectories of solar missions that could be realized with conversion launchers are investigated. The insufficient energy resources of the rocket launchers is compensated by multiple gravity-assist maneuvers near terrestrial planets. A method based on the construction of a set of attainability for all the mission trajectories rather than on optimization of separate trajectories is presented, which makes it possible to analyze the problem more widely and to find global extremums using various criteria. Detailed features of the most rational trajectories are given.     

Ariane transfer vehicle in service of man in orbit

The Ariane transfer vehicle (ATV), an Ariane 5 borne, unmanned propulsion vehicle, is designed to transport the logistics needed to resupply the International Space Station (ISS) and the man tended free flyer (MTFF) step 2 with pressurized and unpressurized cargo and to dispose the waste. The ATV is an expendable vehicle and is disposed of by a safe atmospheric burn up. In accordance with the AR5 schedule it should be operational in 1996 for missions toward ISS and beyond the year 2000 for MTFF 2 missions. The main constituents of the proposed ATV are the modified AR5 third stage L5, an upgraded VEB steering the launcher as well as the ATV and the P/L-adaptor providing mechanical and umbilical links to the payload. The mechanical part of the RVD-kit will be placed on the payload-module, the main RVD sensors are located on the adaptor and the needed computer intelligence will be integrated on the VEB. To minimize the development, and recurring costs, the ATV concept fully complies to the idea of maximum use of existing hardware and software, mainly from the AR5, Hermes and Columbus programs thus minimizing development and recurring costs. The ATV is compatible to ISS, MTFF and OMV and is able to transport logistic modules compatible with NSTS and U.S.-expendable launchers.     

The astronaut and the robot : Short- and long-term scenarios for space technology

A series of major accidents - the explosion of the Space Shuttle Challenger, the destruction of Titan and Delta launchers, and failures of the Ariane rocket series - has led to a reexamination of Western space programmes. In the short term, all satellite launches have been delayed. This is not an insurmountable obstacle, although it will inevitably delay the first space-based tests of SDI hardware. The author outlines the growing gap between the immediate needs of organizations which launch satellites and the more uncertain ambitions of the ‘conquerors’ of space. The former are now bearing the costs of the latter, who are aiming at manned space flights and a human presence in space. In the longer term, these objectives have justifications other than simple industrial and commercial logic. The author suggests that an attempt should be made to reconcile immediate military and industrial needs with the human desire to overcome the ‘Icarus complex’ in the long-term future.     

The hidden costs of reliability and failure in launch systems

In comparing the costs of different launch vehicles, the possibility of the risk of failure is assumed to be accounted for by the cost of insurance. The satellite may be insured against loss during launch, and the launch services provider may offer a “free relaunch.” However, actual costs of reliability and failure extend beyond this. Each failure necessitates an investigation and a “get well” programme by the operating agency, while putting the operations team “on hold” until services can resume. A commercial operator may also lose customer revenue and actual customers through loss of confidence or unavailability. Such costs tend to be hidden, and not evaluated in assessing the effectiveness of a system, but count towards total costs. Failure investigations help to improve system reliability, but this could equally have been achieved by expenditure in development and qualification. Reusable launch vehicles will have different costs associated with reliability and failure. The relationship between reliability and cost, properly assessed, ought to influence the design of both expendable and reusable launch systems.     

Future launchers strategy : the ariane 2010 initiative

With the new cryogenic upper stage ESC, the European heavy launcher Ariane 5+ is perfectly suited to the space market envisioned for the coming decade: flexible to cope with any payload and commercially attractive despite a fierce competition.Current Arianespace projections for the following years 2010–2020 indicate two major trends:

• satellites may still become larger and may require very different final orbits; today's market largely dominated by GEO may well evolve, influenced by LEO operations such as those linked to ISS or by constellations,

• to remain competitive, the launch cost has to be reduced.

The future generation of the European heavy launcher has therefore to focus on an ever increased flexibility with a drastic cost reduction.Two strategies are possible to achieve this double goal:

• reusable launchers, either partially or totally, may ease the access to space, limiting costly expendable stages; the assessment of their technical feasibility and financial viability is undergoing in Europe under the Future Launchers Technology Program (FLTP),

• expendable launchers, derived from the future Ariane 5+.

This second way started by CNES at the end of year 1999 is called the “Ariane 2010 initiative”.The main objectives are simultaneously an increase of 25% in performance and a reduction of 30% in launch cost wrt Ariane 5+.To achieve these very ambitious goals, numerous major modifications are studied:

• technical improvements :

◦ modifications of the Solid Rocket Boosters may consist in filament winding casing, increased loading, simplified casting, improved grain, simplified Thrust Vector Control, …

◦ evolution of the Vulcain engine leading to higher efficiency despite a simplified design, flow separation controlled nozzle extension, propellant management of the two cryogenic stages,

◦ simplified electrical system,

◦ increased standardization, for instance on flanged interfaces and manufacturing processes,

• operational improvements such as launch cycle simplification and standardization of the coupled analyses,

• organizational improvements such as a redistribution of responsibilities for the developments.

All these modifications will of course not be implemented together; the aim is to have a coherent catalogue of improvements in order to enable future choices depending on effective requirements. These basic elements will also be considered for the development of other launchers, in the small or medium size range.     

The impact of launch vehicle type and size on development cost

The technical development trend of future launch vehicle systems is towards fully reusable systems, in order to reduce space transportation cost. However, different types of launch vehicles are feasible, as there are

• —winged two-stage systems (WTS)

• —ballistic single-stage vehicles (BSS)

• —ballistic two-stage vehicles (BTS)

The performance of those systems is compared according to the present state of the art as well as the development cost, based on the “TRANSCOST-Model”. The development costs are shown versus launch mass (GLOW) and pay-load for the three types of reusable systems mentioned above.It is shown that performance optimization and cost minimization lead to different results. It is more economic to increase the vehicle size for achieving higher performance, instead of increasing technical complexity.Finally it is described that due to the essentially lower launch cost of reusable vehicles it will be feasible to recover the development cost by an amortization charge on the launch cost. This possibility, however, would allow commercial funding of future launch vehicle developments.     

Russian program of planetary missions

In the area of Solar System Exploration most of recently proposed mission oriented to the studies of Mars. Except MARS-96 and possibly MARS SAMPLE RETURN missions other Mars missions use Molnija class launchers. All Russian missions heavily involve international partners.     

Ariane in the world launch vehicle market

Roland Deschamps, Secretary General of Arianespace, discusses the evolution of the Ariane family of launchers and the creation of Arianespace to market and manage Ariane production and launch services. Tha launcher market is analysed and the advantages of Ariane compared to the US Shuttle are identified.     

The progress of astronautics in China

China now has thirty years of experience in space. This article traces the development of China's space efforts and the successes China has achieved in space technology, particularly satellites and launchers. China's future plans for space activities are examined, including plans for cooperation with friendly countries, manned space flight, facilities to launch larger space vehicles, and participation in a permanent space station.     

重复使用航天器发展趋势及若干思考

重复使用航天器具有快速、低成本的特性,是自由进出空间的重要技术途径之一。自从２0世纪50年代重复使用航天器的概念被提出以来,历经７０多年,重复使用航天器的研制取得了很大的进步,积累了丰富的经验和教训。基于国内外发展情况,梳理了重复使用航天器的技术路线,深入分析了其发展趋势,从设计、制造、试验、运行维护4个方面探讨了重复使用航天器的特点和难点,并提出了未来重复使用航天器发展的若干思考与建议。     

一种可兼容多型号运载火箭的可重构式活动发射平台（英文）

A launch pad is an important part of the launch vehicle system. It bears the weight of launch vehicles and payloads, and is burnt due to the high-temperature and high-pressure gas flow during launch. This study analyzes the development of launch pads in the world, reviews a reconfigurable mobile launch pad for multiple launchers, then proposes common points and development trends of future launch pads in the world.     

用于相异性设计的模糊重用库

容错设计是提高软件可靠性的有效途径，但是由于设计多样性实现很困难且开销大，导致该项技术实现很困难。为此，提出了一个基于重用的应用框架。该框架的提出将相异性设计过程转变为根据可重用参数从大量具有相同功能软件组件中选择合适的组件来构成容错系统，从而简化了软件开发过程。同时为了更准确地描述组件，采用了模糊逻辑来表达其与上层概念的关联关系。本文介绍了重用库系统结构的设计及其对容错设计的支持。     

Space debris mitigation measures applied to European launchers

In November 1986, more than 20 years ago, an H8 upper stage of Ariane 1 exploded in orbit nine months after the end of its mission. So as to avoid the generation of debris in low Earth orbit, a dedicated complementary development modified the design, introducing systematic passivation of the stage. Ever since this event, space debris mitigation has been a major concern for all launcher activities in Europe.After a short recall of the launchers currently operated by Arianespace as well as those currently developed by ESA with CNES, particularly for the safeguard authority, including the most promising future evolutions, the set of applicable regulations is described. These rules are fundamentally derived from the IADC Guidelines (hence the UNCOPUOS ones), translated into European Code of Conduct and in some more applicable Standards, such as the one prepared by ESA. The process of preparing ISO standards, mainly through the ECSS Working Group, is also described.Three major families can be identified: minimization of Mission Related Objects, Passivation of stages at the end of mission, and orbital protected zones including the so-called 25-year rule.The paper describes how European launchers do or will fulfill these applicable standards, quantifying the efficiency of the mitigation rules, and describing improvement actions currently under study.     

Swords into ploughshares Missiles as commercial launchers

The signing of an INF arms control treaty in 1987 and the reduction in East-West tension has resulted in a surplus of missiles. Getting rid of them remains a problem, but two distinct initiatives have been advanced in the USA and the USSR for their conversion into low-cost launchers. The author describes these two initiatives and discusses the political and economic issues they raise before speculating on the likelihood of their achievement.     

An alternative to Hermes a solution for the European space industry

A variety of valuable roles can be foreseen during the next two decades for a reusable, piloted launch vehicle with a small payload. The authors argue that unfortunately, as currently proposed, the Hermes-Ariane 5 vehicle will not be able to fill the roles required. The authors propose a reusable aerospace transporter-a variant of Hermes - which will provide a solution and allow Europe to take the lead in developing the first fully reusable launch vehicle.     

可重复使用空间往返运输系统的最新发展

可重复使用的空间往返运输系统具有广泛的军事用途和商业应用前景 ,因此成为各国争相发展的目标。本文简要介绍了世界主要航天国家在重复使用运输系统方面的发展情况、技术特点和发展趋势