Search

Abstract: When Ariane 5 ECA development has been decided by Europe to increase Ariane 5 performance, the rule of 25 years in GTO orbit for the upper stage has been anticipated. This was 14 years ago and this rule was known to be satisfied with a perigee lower than 250km. Even when lowering slightly Ariane 5 ECA performance, this maximum perigee altitude has been held and the whole Launch System has been developed under CNES responsibility with this GTO perigee. In the meantime, more precise calculations demonstrated that such a GTO perigee was giving for the ESCA a mean lifetime higher than 25 years. So studies are in progress inside CNES to decrease the perigee and re-enter inside the 25 years lifetime domain. This paper presents a CNES study to reduce the orbital lifetime of Ariane 5''s upper stage that last in GTO after each commercial mission. Usually the aimed orbit has a perigee altitude of 250km, an apogee altitude near to the geostationary position and an inclination between 2° and 7°. These conditions make stage''s mean lifetime superior to 90 years. The CNES study is to expose the possibility to decrease this lifetime by reducing the perigee altitude of the final upper stage orbit through a passivation process optimised to produce orbit modification. It is shown that taking into account material and functional stage constraints the optimised passivation process is able to decrease the perigee by a few tenths of kilometres. [Copyright &y& Elsevier]

Abstract: The French Space Agency (CNES) is currently operating thirteen satellites among which five remote sensing satellites. This fleet is composed of two civilian (SPOT) and three military (HELIOS) satellites and it has been recently completed by the first PLEIADES satellite which is devoted to both civil and military purposes. The CNES operation board decided to appoint a Working Group (WG) in order to anticipate and tackle issues related to the emergency End Of Life (EOL) operations due to unexpected on-board events affecting the satellite. This is of particular interest in the context of the French Law on Space Operations (LSO), entered in force on Dec. 2010, which states that any satellite operator must demonstrate its capability to control the space vehicle whatever the mission phase from the launch up to the EOL. Indeed, after several years in orbit the satellites may be affected by on-board anomalies which could damage the implementation of EOL operations, i.e. orbital manoeuvres or platform disposal. Even if automatic recovery actions ensure autonomous reconfigurations on redundant equipment, i.e. setting for instance the satellite into a safe mode, it is crucial to anticipate the consequences of failures of every equipment and functions necessary for the EOL operations. For this purpose, the WG has focused on each potential anomaly by analysing: its emergency level, as well as the EOL operations potentially inhibited by the failure and the needs of on-board software workarounds… The main contribution of the WG consisted in identifying a particular satellite configuration called “minimal Withdrawal From Service (WFS) configuration”. This configuration corresponds to an operational status which involves a redundancy necessary for the EOL operations. Therefore as soon as a satellite reaches this state, a dedicated steering committee is activated and decides of the future of the satellite with respect to three options: a/. the satellite is considered safe and can continue its mission using the redundancy, b/. the EOL operations must be planned within a mid-term period, or c/. the EOL operations must be implemented as soon as possible by the operational teams. The paper describes this management and operational process illustrated with study cases of failures on SPOT and PLEIADES satellites corresponding to various emergency situations. [Copyright &y& Elsevier]

Abstract: In 1957–1958, the International Geophysical Year (IGY) was the most important scientific cooperation programme in the World, after the Second World War. Thousands of scientists from 67 countries were involved in this large operation, among them a lot of French scientists. IGY was previously called the IPY (International Polar Year) and France, as many other countries, has been involved in the Arctic and Antarctic regions researches. Everybody knows that the IGY is at the origin of Sputnik and the first launch of Russian and American satellites. But, we know less about the IGY rockets programme itself in which France had intended to participate. This paper will discuss this programme with a special highlight on some aspects of the French participation and their relationship with the IGY programme. This approach arises several questions, such as: Which French scientists have been involved? What was the attitude of the French Government about this program, etc. We focus our analysis on the interrogation: did the IGY have any real influence on the origin of the French space research activities? [Copyright &y& Elsevier]

Abstract: The French space adventure started more than 40 years ago. Its rich and long scientific and technical tradition made France able to occupy the place which is hers today. But what does happen to the world of arts, to which the French culture brought so much? Beyond some French artists belonging to the community of the space artists, do arts constitute a true dimension of the French space activity? Conversely, did space influence the national artistic culture? This paper proposes to tackle these questions according to a retrospective historical glance and to offer some prospective reflexions. [Copyright &y& Elsevier]

Abstract: As scholars involved with the Search for Extraterrestrial Intelligence (SETI) have contemplated how we might portray humankind in any messages sent to civilizations beyond Earth, one of the challenges they face is adequately representing the diversity of human cultures. For example, in a 2003 workshop in Paris sponsored by the SETI Institute, the International Academy of Astronautics (IAA) SETI Permanent Study Group, the International Society for the Arts, Sciences and Technology (ISAST), and the John Templeton Foundation, a varied group of artists, scientists, and scholars from the humanities considered how to encode notions of altruism in interstellar messages http://publish.seti.org/art_science/2003 . Though the group represented 10 countries, most were from Europe and North America, leading to the group''s recommendation that subsequent discussions on the topic should include more globally representative perspectives. As a result, the IAA Study Group on Interstellar Message Construction and the SETI Institute sponsored a follow-up workshop in Santa Fe, New Mexico, USA in February 2005. The Santa Fe workshop brought together scholars from a range of disciplines including anthropology, archaeology, chemistry, communication science, philosophy, and psychology. Participants included scholars familiar with interstellar message design as well as specialists in cross-cultural research who had participated in the Symposium on Altruism in Cross-cultural Perspective, held just prior to the workshop during the annual conference of the Society for Cross-cultural Research www.seti.org/altruism . The workshop included discussion of how cultural understandings of altruism can complement and critique the more biologically based models of altruism proposed for interstellar messages at the 2003 Paris workshop. This paper, written by the chair of both the Paris and Santa Fe workshops, will explore the challenges of communicating concepts of altruism that draw on both biological and cultural models. [Copyright &y& Elsevier]

Although the threat caused by an impact of near-Earth objects (NEOs) has been increasingly recognized by the international community both at a scientific and political level, no study is addressing this issue in an interdisciplinary manner. A project has been carried out at the International Space University (ISU), located in Strasbourg, France, addressing the problem of the response to a NEO threat, including space-based missions, Earth-based mitigation, political, organizational and space-law issues. This paper summarizes the main results of this study. In order to determine an appropriate response, a new system of classification of the different NEO threat scenarios was created. A specific case study was examined in the project. The threat scenario involved the NEO named 1997 XF11, with response options ranging from deflection, to destruction using the concept known as the “billiards shot”. [Copyright &y& Elsevier]

This paper outlines the space Fundamental Physics projects developped under CNES responsability together with the french scientific community, either in the national french programme or in the french contribution to the ESA programme, mainly:

This paper proposes to discuss space research cooperation between France and the United States as it existed at the beginning of the 1960s.Among NASA's missions, when created in 1958, was to conduct a policy of international cooperation. Great Britain and Canada responded rapidly to the NASA's proposals.With France, however, the situation was quite different. At that time, Paris wanted to develop large scale space research activities of its own.For this purpose, in January 1959, the French government created the “Comite´ des Recherches Spatiales”, which had two missions: to organize the space research in France and to participate in international space affairs. Although French research at that time was sufficiently advanced in sounding rockets and military missiles to develop a program whose objective was to create a national launcher, France's scientists did not really have enough experience in satellite design, unlike most other countries involved in space research during this period.At this time, several cooperative programs were initiated between France and the United States, in fields such as rocket experiments, visual observation satellites and satellites tracking. However, the first major cooperative program between the two countries concerned the development of a scientific satellite—later known as FR-1— which was launched in December 1965. [Copyright &y& Elsevier]