Observations from over a decade of experience in developing faster, better, cheaper missions for the NASA small explorer program

The Small Explorer (SMEX) Project at NASA Goddard Space Flight Center (GSFC) has accumulated nearly a decade of experience building missions with the underlying philosophy of “Faster, Better, Cheaper” (FBC). Five satellites are now successfully operating on-orbit with only one serious instrument anomaly. Together this Project has accumulated 14.6 years of on-orbit experience without a spacecraft bus failure. Additionally, this project, under the Explorer Technology Infusion effort, has developed a protoflight version of a 21^st Century FBC spacecraft bus that has just completed environmental qualification and has been selected at the base spacecraft for NASA's Triana mission. Design and production of these six high performance spacecraft, in just ten years time, has provided a unique base of experience from which to draw lessons learned. This paper will discuss the fundamental practices that have been used by the SMEX Project in achieving this record of success.     

Flight demonstration of new thruster and green propellant technology on the PRISMA satellite

The concept of a storable liquid monopropellant blend for space applications based on ammonium dinitramide (ADN) was invented in 1997, within a co-operation between the Swedish Space Corporation (SSC) and the Swedish Defense Research Agency (FOI). The objective was to develop a propellant which has higher performance and is safer than hydrazine. The work has been performed under contract from the Swedish National Space Board and ESA. The progress of the development has been presented in several papers since 2000.ECAPS, a subsidiary of the Swedish Space Corporation was established in 2000 with the aim to develop and market the novel “high performance green propellant” (HPGP) technology for space applications. The new technology is based on several innovations and patents w.r.t. propellant formulation and thruster design, including a high temperature resistant catalyst and thrust chamber.The first flight demonstration of the HPGP propulsion system will be performed on PRISMA. PRISMA is an international technology demonstration program with Swedish Space Corporation as the Prime Contractor.This paper describes the performance, characteristics, design and verification of the HPGP propulsion system for PRISMA. Compatibility issues related to using a new propellant with COTS components is also discussed. The PRISMA mission includes two satellites in LEO orbit were the focus is on rendezvous and formation flying. One of the satellites will act as a “target” and the main spacecraft performs rendezvous and formation flying maneuvers, where the ECAPS HPGP propulsion system will provide delta-V capability.The PRISMA CDR was held in January 2007. Integration of the flight propulsion system is about to be finalized.The flight opportunity on PRISMA represents a unique opportunity to demonstrate the HPGP propulsion system in space, and thus take a significant step towards its use in future space applications. The launch of PRISMA scheduled to 2009.     

Searching for the magic bullet

A powerful statistical tool, paired-comparison, was tested as a method to determine the relative value American people place on two possibly competing paradigms in the United States Space Program: “Space as a Place to Explore” and “Civil and Commercial Uses of Space”. A limitation of the results, but not the methodology, is the participants were college students, not “voting” adults. Reliability and validity of items were developed and tested in two studies suggesting that the paired-comparison method is a reliable and powerful tool for measuring the relative value the public may place on programs within the US Space Program.     

Space agencies and the UN system: the Space Agency Forum (SAF) 10th Plenary

The Space Agency Forum (SAF) met for its 10th plenary meeting in Bremen on 30 September 2003. Its motto was “Space Agencies and the UN System”. Following various presentations on relevant issues, including the UN Space Applications Programme and the follow-up of UNISPACE III, SAF members discussed their participation in these fields. The meeting resulted in a number of inputs to these issue areas and coordinated approaches vis-à-vis policy questions.     

X-38, CRV and CRV Evolution Program Overview and European Role

The X-38 Project forms part of the “X” prototype vehicle family developed by the United States. Its development was initiated by NASA to prepare the Crew Return Vehicle (CRV). The European participation in the X-38 Program has been significantly extended since the start of the X-38 cooperation in 1997 and is realized by ESA's “Applied Reentry Technology Program” and the German/DLR “Technologies for Future Space Transportation Systems” (TETRA) Project. European contributions to the X-38 Vehicle 201, (V-201) can be found in all technical key areas. The orbital flight and reentry with the X-38 V-201 will conclude the X-38 project in 2002.The CRV will be used from about mid-2005 as ’ambulance‘, ’lifeboat‘ or as alternate return vehicle for the crew of the International Space Station. Recognizing the very productive and mutually beneficial cooperation established on X-38, NASA and ESA have decided to continue this cooperation into the development of the operational CRV. The Phase C/D will be completed shortly after the Critical Design Review, scheduled for August 2002. The CRV production phase will start in October 2002 and will cover production of four CRV vehicles, ending in 2006.Based on the objective to identify a further evolution potential of the CRV towards a Crew Cargo Transfer Vehicle (CCTV), NASA has implemented upgrade studies in the CRV Phase C/D.     

ST-5微小卫星与星座及其空间飞行验证——为未来微小卫星的空间应用展现广阔前景

美国NASA于2006年3月22日成功发射三颗ST-5微小卫星,并组成星座,用于空间地磁观测。经过90天飞行演示,于6月20日顺利结束。演示验证很成功。卫星重25kg,功率24W具有通常卫星全部功能。卫星多项先进技术在演示中得到肯定,空间观测获得史无前例的数据。为此,文章介绍了ST-5微小卫星的先进技术和设计经验。ST-5将为今后微小卫星空间应用展现广阔前景。     

Earth remote sensing as an effective tool for the development of advanced innovative educational technologies

Current educational system is facing a contradiction between the fundamentality of engineering education and the necessity of applied learning extension, which requires new methods of training to combine both academic and practical knowledge in balance. As a result there are a number of innovations being developed and implemented into the process of education aimed at optimizing the quality of the entire educational system. Among a wide range of innovative educational technologies there is an especially important subset of educational technologies which involve learning through hands-on scientific and technical projects. The purpose of this paper is to describe the implementation of educational technologies based on small satellites development as well as the usage of Earth remote sensing data acquired from these satellites. The increase in public attention to the education through Earth remote sensing is based on the concern that although there is a great progress in the development of new methods of Earth imagery and remote sensing data acquisition there is still a big question remaining open on practical applications of this kind of data. It is important to develop the new way of thinking for the new generation of people so they understand that they are the masters of their own planet and they are responsible for its state. They should desire and should be able to use a powerful set of tools based on modern and perspective Earth remote sensing. For example NASA sponsors “Classroom of the Future” project. The Universities Space Research Association in United States provides a mechanism through which US universities can cooperate effectively with one another, with the government, and with other organizations to further space science and technology, and to promote education in these areas. It also aims at understanding the Earth as a system and promoting the role of humankind in the destiny of their own planet. The Association has founded a Journal of Earth System Science Education. Authors describe an effective model of educational technology developed in the Center for Earth Remote Sensing of Bauman Moscow State Technical University and based on scientific and educational organizations integration in the field of applied studies. The paper also presents how students are being trained to acquire and process satellite imagery data from Terra and Aqua satellites. It also reveals the results of space monitoring for Russia's ecologically complex regions conducted by Bauman Moscow State Technical University students in cooperation with specialists from the Laboratory for Aerospace Methods of Moscow State University named after M. Lomonosov.     

International Practices to Protect the Geostationary Ring

Since more than 20 years reorbiting of geostationary satellites at the end of their mission is recommended and partially performed to protect the GEO environment. Now a worldwide accepted reorbiting altitude was defined by the Inter-Agency Space Debris Coordination Committee (IADC). Still only one-third of the aging satellites follow this IADC rule. Based on orbital data in the DISCOS database, the situation in the geostationary ring is analyzed. From 878 known objects, 305 are controlled inside their longitude slots, 353 are drifting above, below or through GEO, and 125 are in a libration orbit (status of January 2001). In the last four years (1997–2000) 58 spacecraft reached end-of-life. Twenty of them were reorbited in compliance with the IADC recommendations, 16 were reorbited below this recommendation and 22 were abandoned without any end-of-life disposal manoeuvre.     

Creating a productive international partnership in the Vision for Space Exploration

When US President George W. Bush on 14 January 2004 announced a new US “Vision for Space Exploration”, he called for international participation in “a journey, not a race”, a call received with skepticism and concern elsewhere. But, after a slow start in implementing this directive, during 2006 NASA has increased the forward momentum of action on the program and of discussions on international cooperation in exploring “the Moon, Mars, and beyond”. There are nevertheless a number of significant top-level issues that must be addressed if a cooperative approach to human space exploration is to be pursued. These include the relationship between utilization of the ISS and the lunar exploration plans, integration of potential partners’ current and future capabilities into the exploration plans, and the evolving space-related intentions of other countries.     

Parametric study of the diversion of a near Earth object on an Earth intersecting trajectory

To date, NASA's “Near Earth Object Program” has discovered over 5500 comets and asteroids on trajectories that bring them within “the neighborhood” of Earth's orbit. Nearly 1000 of these objects are classified as “potentially hazardous,” passing within 0.05 astronomical units of Earth's orbit. Discovery rates of such threatening bodies increase each year. Given this multitude of threats, in addition to evidence that the planet has absorbed many impacts over its history, it is reasonable to assume that another object will strike the Earth at some point in the future. Consequently, researchers have studied and proposed several mitigation techniques for such an occurrence. This study seeks to determine how effectively the attachment of a tether and ballast mass would divert the trajectory of such threatening objects. Specifically, the study analyzes the effects over time of such a system on objects of varying orbital semimajor axis and eccentricity, using various tether lengths and ballast masses. It was determined that the technique is most effective for NEOs with high eccentricity and small semimajor axis, and that system performance increases as tether length and ballast mass increase.     

NASA''s small spacecraft technology initiative “Clark” spacecraft

The Small Satellite Technology Initiative (SSTI) is a National Aeronautics and Space Administration (NASA) program to demonstrate smaller, high technology satellites constructed rapidly and less expensively. Under SSTI, NASA funded the development of “Clark,” a high technology demonstration satellite to provide 3-m resolution panchromatic and 15-m resolution multispectral images, as well as collect atmospheric constituent and cosmic x-ray data. The 690-Ib. satellite, to be launched in early 1997, will be in a 476 km, circular, sun-synchronous polar orbit. This paper describes the program objectives, the technical characteristics of the sensors and satellite, image processing, archiving and distribution. Data archiving and distribution will be performed by NASA Stennis Space Center and by the EROS Data Center, Sioux Falls, South Dakota, USA.     

Stepping stones to the future: Achieving a sustainable lunar outpost

The current emphasis in the US and internationally on lunar robotic missions is generally viewed as a precursor to possible future human missions to the Moon. As initially framed, the implementation of high level policies such as the US Vision for Space Exploration (VSE) might have been limited to either human lunar sortie missions, or to the testing at the Moon of concepts-of-operations and systems for eventual human missions to Mars [White House, Vision for Space Exploration, Washington, DC, 14 January, 2004. [1]]. However, recently announced (December 2006) US goals go much further: these plans now place at the center of future US—and perhaps international—human spaceflight activities a long-term commitment to an outpost on the Moon.Based on available documents, a human lunar outpost could be emplaced as early as the 2020–2025 timeframe, and would involve numerous novel systems, new technologies and unique operations requirements. As such, substantial investments in research and development (R&D) will be necessary prior to, during, and following the deployment of such an outpost. It seems possible that such an outpost will be an international endeavor, not just the undertaking of a single country—and the US has actively courted partners in the VSE. However, critical questions remain concerning an international lunar outpost. What might such an outpost accomplish? To what extent will “sustainability” be built into the outpost? And, most importantly, what will be the outpost's life cycle cost (LCC)?This paper will explore these issues with a view toward informing key policy and program decisions that must be made during the next several years. The paper will (1) describe a high-level analytical model of a modest lunar outpost, (2) examine (using this model) the parametric characteristics of the outpost in terms of the three critical questions indicated above, and (3) present rough estimates of the relationships of outpost goals and “sustainability” to LCC. The paper will also consider possible outpost requirements for near-term investments in enabling research in light of experiences in past advanced technology programs.     

Small spacecraft “UNISAT” launched by the “start-1” launcher

The preliminary estimations show that the contemporary level of electronic and information engineering makes it possible to create a small s/c of 150–200 kg mass capable to solve both the problems of Earth remote sensing and many other applied and scientific problems orbiting the planets at 500–1000 km. In accordance with the fundamental criterion for choosing parameters of small multipurpose spacecraft the small UNISAT s/c has been created on the basis of a unified space platform. The design provides for s/c energetic, thermal and space-saving parameters satisfying the conditions for accommodation of various-purpose payload and a possibility of using relatively inexpensive and light launchers like “Start-1” mobile launch complexes. Space platform mass is 100–120 kg; permissible payloads (PL) mass is 40–80 kg; maximal average power consumption of the payload is up to 60 W; three-axes orientation accuracy up to 0.001 deg./s; s/c lifetime is not less than 3–5 years.     

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 Debris at the United Nations

Rules for activities in outer space are agreed upon in the Committee on the Peaceful Uses of Outer Space of the United Nations. Several international treaties have been adopted in the 1970s, that is, at a time before space debris became a concern for the international community. In the years 1979–1988 numerous documents were prepared by the UN Secretariat on space debris, but no official discussions of the problem were initiated by states members of the COPUOS. First proposals for introducing the matter to the UN appeared around 1988, after important studies on the subject were published by states and leading intergovernmental organizations. Also the International Telecommunication Union became concerned about the proliferation of space debris in the geostationary orbit and adopted in 1993 a recommendation to restrict the generation of debris and to re-orbit satellites approaching the end of their active lives into disposal orbits beyond the belt populated by active satellites. In 1994, the UN started discussing scientific and technical aspects of space debris. In the following years, with the assistance of experts from prominent space agencies, it elaborated a Technical Report on space debris. Legal aspects of the problem have not yet begun being discussed because the necessary consensus among states members of the COPUOS has not yet been achieved. Very recently, the UN received first information on a wider subject, space traffic management.     

Columbia and Challenger: organizational failure at NASA

The National Aeronautics and Space Administration (NASA)—as the global leader in all areas of spaceflight and space science—is a unique organization in terms of size, mission, constraints, complexity and motivations. NASA's flagship endeavor—human spaceflight—is extremely risky and one of the most complicated tasks undertaken by man. It is well accepted that the tragic destruction of the Space Shuttle Challenger on 28 January 1986 was the result of organizational failure. The surprising disintegration of the Space Shuttle Columbia in February 2003—nearly 17 years to the day after Challenger—was a shocking reminder of how seemingly innocuous details play important roles in risky systems and organizations. NASA as an organization has changed considerably over the 42 years of its existence. If it is serious about minimizing failure and promoting its mission, perhaps the most intense period of organizational change lies in its immediate future. This paper outlines some of the critical features of NASA's organization and organizational change, namely path dependence and “normalization of deviance”. Subsequently, it reviews the rationale behind calling the Challenger tragedy an organizational failure. Finally, it argues that the recent Columbia accident displays characteristics of organizational failure and proposes recommendations for the future.     

Structure and thermal control of panel extension satellite (PETSAT)

Panel ExTension SATellite (PETSAT) [S. Nakasuka, Y. Nakamura, Panel extension satellite (PETSAT)—a novel satellite concept consisting of modular, functional and plug-in panels, in: 24th International Symposium on Space Technology and Science, invited talk, 2004-o-2, 2004 [1]] is a satellite which is made of several “functional panels”. Each panel has a special dedicated function and various combinations of different kinds of functional panels enable PETSAT to deal with various mission requirement. Development of PETSAT requires four interface requirements. These are mechanical interface, thermal interface, electrical interface and information interface. In this paper, mechanical interface and thermal interface of PETSAT are especially focused on and introduced. In the development of PETSAT issues about mechanical interface corresponds to panel structure and deployment mechanism. The structure of PETSAT is designed so as to have light weigh, enough space for devices and high stiffness. And deployment system has simple mechanism to avoid vacuum metalizing and improve reliability. On the other hand, approaches for thermal interface [K. Higashi, S. Nakasuka, Y. Sugawara, H. Sahara, K. Koyama, C. Kobayashi, T. Okada, Thermal control of panel extension satellite (PETSAT), in: 25th International Symposium on Space Technology and Science, 2006-j-02, 2006 [2]] are homogenization of temperature within panel and between panels. Homogenization of temperature within panels can be realized by heat lane plate, and that between panels is realized by magnetic fluid loop with magnetic heat pump. These approaches for mechanical and thermal interface are demonstrated in SOHLA-2 [Y. Sugawara, S. Nakasuka, T. Eishima, H. Sahara, Y. Nakamura, K. Koyama, C. Kobayashi, T. Okada, Elemental technologies for realization of panel extension satellite (PETSAT), in: 25th International Symposium on Space Technology and Science, 2006-J-01, 2006 [3]] that is satellite of technology demonstration for PETSAT.     

The Nation of Celestial Space

Using family interviews and archive material, this article outlines the forgotten history of the Nation of Celestial Space, brainchild of a Chicago public relations man, James T. Mangan. From 1948 to 1970 Mangan sought international recognition for his micronation, and repeatedly protested at satellites encroaching upon his domain. Celestia issued passports to the Moon to astronauts, and its own currency and stamps, anticipating by decades the current debate on and ‘selling’ of property rights in space.     

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.