Why rover preparatory programmes? The example of the French programme “VAP”

The very first activities concerning planetary rovers began in 1964 in the Soviet Union and in the United States for lunar missions. Nowadays, with the increase of new mission needs and technical possibilities, several space agencies have engaged in some preliminary programmes in that area with the following objectives:

• —to prepare their involvement in future international rover missions

• —to ease contacts/discussions between scientists and engineers

• —to study and develop a new generation of in situ experiments

• —to perform system/mission analysis in conjunction with the definition of the mission objectives

• —to analyze robotic problematics and implement robotic concepts in the rover architectures.

To perform these activities, several organizations have been set up in Russia, the United States, Japan, Italy and France, according to the relative weight of space engineering over robotic research.

In the case of the French programme (‘VAP—Automatic Planetary Rover’), the organization is based on a partnership between the CNES, a scientific committee, four national research laboratories and industries in order to optimize scientific and technical work, with an optimal use of past robotic research studies, as well as to generate spin-offs for Earth applications. Indeed, as a preliminary result, we now have a co-operative agreement with Russia to procure cameras and associated software for the autonomous navigation of the Marsokhod 96 and 2 projects for terrestrial applications of robotic concepts defined within the framework of the VAP programme.     

Innovations for competitiveness: European views on “better-faster-cheaper”

The paper elaborates on “ lessons learned” from two recent ESA workshops, one focussing on the role of Innovation in the competitiveness of the space sector and the second on technology and engineering aspects conducive to better, faster and cheaper space programmes. The paper focuses primarily on four major aspects, namely:

1. a) the adaptations of industrial and public organisations to the global market needs;

2. b) the understanding of the bottleneck factors limiting competitiveness;

3. c) the trends toward new system architectures and new engineering and production methods;

4. d) the understanding of the role of new technology in the future applications.

Under the pressure of market forces and the influence of many global and regional players, applications of space systems and technology are becoming more and more competitive. It is well recognised that without major effort for innovation in industrial practices, organisations, R&D, marketing and financial approaches the European space sector will stagnate and loose its competence as well as its competitiveness. It is also recognised that a programme run according to the “better, faster, cheaper” philosophy relies on much closer integration of system design, development and verification, and draws heavily on a robust and comprehensive programme of technology development, which must run in parallel and off-line with respect to flight programmes.

A company's innovation capabilities will determine its future competitive advantage (in time, cost, performance or value) and overall growth potential. Innovation must be a process that can be counted on to provide repetitive, sustainable, long-term performance improvements. As such, it needs not depend on great breakthroughs in technology and concepts (which are accidental and rare). Rather, it could be based on bold evolution through the establishment of know-how, application of best practices, process effectiveness and high standards, performance measurement, and attention to customers and professional marketing. Having a technological lead allows industry to gain a competitive advantage in performance, cost and opportunities. Instrumental to better competitiveness is an R&D effort based on the adaptation of high technology products, capable of capturing new users, increasing production, decreasing the cost and delivery time and integrating high level of intelligence, information and autonomy. New systems will have to take in to account from the start what types of technologies are being developed or are already available in other areas outside space, and design their system accordingly. The future challenge for “faster, better, cheaper” appears to concern primarily “cost-effective”, performant autonomous spacecraft, “cost-effective”, reliable launching means and intelligent data fusion technologies and robust software serving mass- market real time services, distributed via EHF bands and Internet.

In conclusion, it can be noticed that in the past few years new approaches have considerably enlarged the ways in which space missions can be implemented. They are supported by true innovations in mission concepts, system architecture, development and technologies, in particular for the development of initiatives based on multi-mission mini-satellites platforms for communication and Earth observation missions. There are also definite limits to cost cutting (such as lowering heads counts and increasing efficiency), and therefore the strategic perspective must be shifted from the present emphasis on cost-driven enhancement to revenue-driven improvements for growth. And since the product life-cycle is continuously shortening, competitiveness is linked very strongly with the capability to generate new technology products which enhance cost/benefit performance.     

Potential evolution of an international moon base programme

The Moon is a major target in expanding human activity in Space. President Bush has called for a Space Exploration Initiative. European participation may depend on achieving an affordable programme and identifying distinct elements for non-U.S. participation. Affordability requires that all participants can influence the “cost to user” of Base operations. If lunar activity is to evolve towards resource exploitation, there will need to be a progressive reduction in operating costs. European interest would prefer participation that allowed longer-term independent interests. The paper addresses how non-U.S. agencies could contribute valuable elements to an International Moon Base while meeting three criteria:

• — Keep a core infrastructure under U.S. control.

• — Avoid a total reliance by the partner on U.S. services.

• — Allow the partner to evolve towards an eventual, semi-autonomous or autonomous capability.

The paper illustrates possible implications of meeting these constraints through “mini infrastructures” combining several elements to form a working architecture. It is concluded that any European participation in an International Moon Base Programme should contain both Space transport and surface elements.     

The pharao project: Towards a space clock using cold cs atoms

For several years, the “BNM-Laboratoire Primaire du Temps et des Fréquences” has worked on a cold atom frequency standard. With a cesium atomic fountain a resonance line width of 700 mHz has been obtained leading to a short-term stability of 2 × 10⁻¹³ τ^−1/2 down to 2 × 10⁻¹⁵ at 10⁴ s. A first evaluation of the fountain accuracy has been performed resulting in an accuracy of 3 × 10⁻¹⁵, three times better than previously achieved with thermal beams frequency standards. In the atomic fountain, gravity limits the interaction time to ˜1 s, hence the resonance line width to ˜0.5 Hz. A factor of 10 reduction in the line width could be obtained in a micro-gravity environment. The “Centre National d'Etudes Spatiales” (the French space agency), the “BNM-Laboratoire Primaire du Temps et des Fréquences”, the “Laboratoire de l'Horloge Atomique” and the “Laboratoire Kastler Brossel” have set up a collaboration to investigate a space frequency standard using cold atoms: the PHARAO project. A microgravity prototype has been constructed and operated first in the reduced gravity of aircraft parabolic flights in May 1997. It is designed as a transportable frequency standard. The PHARAO frequency standard could be a key element in future space missions in fundamental physics such as SORT (solar orbit relativity test), detection of gravitational waves, or for the realization of a global time scale and a new generation of positioning system.     

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.     

The data compression problem for the “GAIA” astrometric satellite of ESA

Space-based astrometry has a great tradition at ESA. The first space-based astrometric satellite in history, “Hipparcos”, was launched by ESA in 1989 and, in spite of orbital problems, was able to accomplish almost all of its tasks until it was finally shut down in 1993. The results of the Hipparcos mission were published by ESA in 1997 in the form of six CD-ROMs: the Hipparcos Catalogue contains 118,218 entries with median astrometric precision of around 1 milliarcsec, and specific results for double and multiple systems. In practice, Hipparcos drew for the first time the three-dimensional “map” of the spherical region of the Galaxy surrounding the Sun and having a radius of roughly 1,000 light years.

Then, in 1995, ESA launched the study of a new astrometric satellite, named “GAIA” and about a hundred times more powerful than Hipparcos, i.e. with median astrometric precision of around 10 microarcsec. This new satellite is intended to measure the parallaxes of over 50 million stars in the Galaxy, at least for the brightest stars, and this would mean to “draw” the three-dimensional map of the whole Galaxy, reaching out even to the Magellanic Clouds, 180,000 light years away.

The team of European scientists and engineers now designing GAIA, however, is facing hard technological difficulties. One of these is the design and coding of radically new and ultra-powerful mathematical algorithms for the on-board compression of the 50-million-stars data that GAIA will send to Earth from its intended geostationary orbit. Preliminary estimates of the raw data rates from the GAIA focal plane, in fact, are of the order of a few Gigabits per second. To reduce the data stream to the envisaged telemetry link of 1 Megabit per second, on-board data compression with a 1 to 1,000 ratio is the target. Clearly, this is far beyond the capabilities of any lossless compression technique (enabling compression ratios of 1 to some tens), and so some “wise” lossy compression mathematical procedure must be adopted.

In this paper a GAIA-adapted lossy data compression technique is presented, based on the Karhunen-Loève Transform (KLT). The essence of this method was already used by NASA for the Galileo mission when the large antenna got stuck and the mission was rescued by re-programming the on-board computer in terms of the KLT. That transform was officially named ICT — “Integer Cosine Transform” — by the NASA-JPL team led by Dr. Kahr-Ming Cheung. But the KLT here described for GAIA will of course differ from the JPL one in many regards, owing to the advances in computer technology.

Finally, estimates are also given about the possibility of using the KLT for onboard data compression in case GAIA is going to be put into orbit around the Lagrangian point L2 of the Earth-Sun system, and, above all, in case the number of stars to be observed is actually raised from 50 millions to one billion, as ESA currently appears to be likely to pursue.     

Planetary Defense From Space: Part 1-Keplerian Theory

A system of two space bases housing missiles is proposed to achieve the Planetary Defense of the Earth against dangerous asteroids and comets. We show that the layout of the Earth–Moon system with the five relevant Lagrangian (or libration) points in space leads naturally to only one, unmistakable location of these two space bases within the sphere of influence of the Earth. These locations are at the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth).

We show that placing bases of missiles at L1 and L3 would cause those missiles to deflect the trajectory of asteroids by hitting them orthogonally to their impact trajectory toward the Earth, so as to maximize their deflection. We show that the confocal conics are the best class of trajectories fulfilling this orthogonal deflection requirement.

An additional remark is that the theory developed in this paper is just a beginning of a larger set of future research work. In fact, while in this paper we only develop the Keplerian analytical theory of the Optimal Planetary Defense achievable from the Earth–Moon Lagrangian points L1 and L3, much more sophisticated analytical refinements would be needed to:

1. Take into account many perturbation forces of all kinds acting on both the asteroids and missiles shot from L1 and L3;

2. add more (non-optimal) trajectories of missiles shot from either the Lagrangian points L4 and L5 of the Earth–Moon system or from the surface of the Moon itself;

3. encompass the full range of missiles currently available to the US (and possibly other countries) so as to really see “which asteroids could be diverted by which missiles”, even in the very simplified scheme outlined here.

Outlined for the first time in February 2002, our Confocal Planetary Defense concept is a Keplerian Theory that proved simple enough to catch the attention of scholars, representatives of the US Military and popular writers. These developments could possibly mark the beginning of an “all embracing” mathematical vision of Planetary Defense beyond all learned activities, dramatic movies and unknown military plans covered by secret.     

Some problems of selection and evaluation of the Martian suit enclosure concept

One of the most important tasks for preparation of a future manned mission to Mars is to create a space suit, which ensures efficient and safe operation of the man on the planet surface.

The concept of space suit (SS) utilisation on the Mars surface will be determined mainly by the Mars mission scenario. Currently the preference is given to utilisation of robotics with the crew driving a Mars rover vehicle, whereby the suit will be used solely as an additional safety means.

However, one cannot exclude the necessity of a durable self-contained stay of the man outside a pressurised compartment, to pick up, for instance, soil samples or do certain repair work in case of an emergency.

The requirements to the Mars suit and especially to the personal self-contained life support system (LSS) will depend in many respects on the Mars environmental conditions, the space vehicle system concept and performance characteristics, the airlock and its interface design, the availability of expendable elements for the LSS, etc.

The paper reviews principal problems, which have to be solved during development of the Martian suit. A special attention is paid to the issue of suited man mobility during traversing on the planet surface.

The paper also reviews the arguments for application of a suit semi-rigid design concept and evaluates potentialities of using certain elements of the existing “Orlan” type suit.

The paper presents results of a number of studies on selection of the planetary SS enclosure concept and on experimental evaluation of mobility of the lower torso and leg enclosures in conjunction with a specially designed prototype model (tentative model) of the SS enclosure.     

Lunar oxygen: Economic benefit for transportation systems and in situ production by fluorination

The use of oxygen produced on the Moon—called “MOONLOX”—is considered as a propellant component for a reusable Earth-Moon transportation system consisting of an aeroassisted orbital transfer vehicle and a lunar bus for lunar descent/ascent. Conditions for economic benefit are discussed and the processing concept of a lunar oxygen plant based on fluorination is presented. It is shown that the necessary mass of supply from Earth for MOONLOX-production is an important parameter, which may not be neglected due to its strong influence on the economy. In the ideal case where no supplies from Earth are required a reduction of up to 50% in masses to be launched into low Earth orbit can be obtained for a typical lunar mission with use of MOONLOX compared to a reference scenario with Earth-derived propellant. Mass-saving decreases, however, significantly with increasing supply from Earth until a critical supply-rate is reached—measured in percentage of MOONLOX-mass produced and consumed—beyond which mass-saving and thus economically promising lunar oxygen production is no longer possible. This critical supply-rate depends on the scenario for MOONLOX-utilization and is much larger in the case of in situ use of MOONLOX on the lunar surface, e.g. as ascent propellant for the lunar bus, than in the case of export for complete refuelling of both space vehicles. The latter scenario therefore requires significantly more autonomy for MOONLOX-production. The reduction of masses to be transported into low Earth orbit and corresponding MOONLOX-consumption define for given specific Earth-to-LEO transportation costs an upper limit on MOONLOX-production costs beyond which economic benefit is not possible. Depending on the MOONLOX-utilization strategy this upper limit varies between 3000 and 55000 $/kg for current Earth-to-LEO transportation costs.     

Electrophotometrical studies of equatorial and tropical arcs on board the Salyut-6 orbital station

The results from the electrophotometric investigation of the equatorial and tropical ionospheric arcs on board the orbital station “Salyut-6”, carried out with Bulgarian photometer “Duga”, intended for measurements of the self-radiation of the Earth's upper atmosphere in the lines λ = 6300 Å, λ = 5577 Å, λ = 4278 Å and λ = 6563 Å, are analyzed. From the obtained results of the intensity of the measured emissions is established by calculation that the cause of these arcs is the plasma drift downwards, which leads to intensification of the dissociative recombination of the ions O₂⁺ and of the radiative recombination of O⁺.     

Economics of telecommunications space segments

This paper proposes a complete model for assessing the economics of telecommunications satellite systems, accounting for spacecraft development and manufacturing, launch and operations in orbit. This allows to account for such parameters as the mass and lifetime of the satellites, the number and type of payloads, the number of satellites procured and launched, the spare policy, the launch vehicle, the insurances, the satellite average MTTF and the management of the space segment efforts.

The model is divided into four parts: the spacecraft mass model, the spacecraft procurement cost model, the MTTF model and the space segment cost-effectiveness model. It provides for the rapid solution of a number of problems within a wide range of parameters such as assessing the influence on space segment economics of —certain satellite technologies, —satellite and payload mass, —number of payloads per spacecraft, —satellite lifetime, or —spare policy.     

Bistatic radar as a tool for earth investigation using small satellites

Bistatic radar is a facility for the Earth remote sensing, which uses large spatial diversity between its transmitter and receiver. Nomogram method is proposed to determine the radar's parameters. Analysis of the nomograms has shown that modern onboard radio facilities allow to obtain spatial resolution of about 100 m at the wavelength λ = 3 cm for LEO satellite (H = 350 km). Experiments of bistatic radiolocation of the Earth near the radioshadow zone were provided using telecommunication link “MIR” orbital station — GEO satellite at wavelength λ = 32 cm. For the first time in practice of bistatic radiolocation of the Earth from space reflected signal in radioshadow zone was observed.The analysis of experimental results verified the developed radiophysical model with the value of sea water conductivity σ = 7.0 mo/m and absorption coefficient due to atmospheric oxygen χ = 0.0096±0.0024 dB/km.     

New results for the space radiation environment of MIR space station obtained by Liulin dosimeter-radiometer. Comparison with LET spectrometer NAUSICAA

Since 1988 high sensitivity semiconductor dosimeter-radiometer “Liulin” worked on board of MIR space station. Device measured the absorbed dose rate and the flux of penetrating particles. The analysis of the data hows the following new results:

In October 1989 and after March 24, 1991, two additional stable maximums in flux channel were observed in the southern-eastern part of South Atlantic Anomaly (SAA). These two maximums existed at least several months and seem to be due to trapped high energy electron and proton fluxes. In April 1991 additional maximums were localized in the following geographical coordinates regions: LATITUDE = (−35 °)–(−50 °) LONGITUDE = 332 ° − 16 ° and lat.(−46 °)–(−52 °) long. 360 ° − 60 °. Additional maximums diffusion occurs inside radiation belt. Appearance of these maximums seems to be closely connected with preceding powerful solar proton events and associated geomagnetic dynamics of new belt disturbances. After the series of solar proton events in June 1991 we observed significant enhancement of this new radiation belt formation. To achieve sufficient accuracy of dose rate predictions in low Earth orbits the structure and dynamics of new belt should be carefully analyzed to be included in a new environment model.

From the inter comparison of the data from “Liulin” and French developed tissue equivalent LET spectrometer NAUSICAA in the time period August–November 1992 we come to the following conclusions: Mainly there is good agreement between both data sets for absorbed dose in the region of SAA; Different situation of the instruments on the station can explain the cases when differences up to 2 times are observed; At high latitudes usually the tissue equivalent absorbed dose observations are 2 times larger than “Liulin” doses.     

Lessons learned from Mir--a payload perspective

Among the principal objectives of the Phase 1 NASA/Mir program were for the United States to gain experience working with an international partner, to gain working experience in long-duration space flight, and to gain working experience in planning for and executing research on a long-duration space platform. The Phase 1 program was to provide the US early experience prior to the construction and operation of the International Space Station (Phase 2 and 3). While it can be argued that Mir and ISS are different platforms and that programmatically Phase 1 and ISS are organized differently, it is also clear that many aspects of operating a long-duration research program are platform independent. This can be demonstrated by a review of lessons learned from Skylab, a US space station program of the mid-1970s, many of which were again “learned” on Mir and are being “learned” on ISS. Among these are optimum crew training strategies, on-orbit crew operations, ground support, medical operations and crew psychological support, and safety certification processes.     

GEO编队空间机器人系统交会方法

针对地球静止轨道（GEO）上被服务航天器的远距离和非合作特点,提出一种高自主、高协同、多任务的编队空间机器人在轨服务系统方案,实现对非合作目标的自主交会接近。首先,分析GEO卫星轨道约束力小的轨道特征和非合作的信息交互特征,给出由操作空间机器人和监视空间机器人组成的编队在轨服务系统,设计交会接近相对测量分系统以及在轨服务飞行任务;接着,给出典型远距离交会接近的多视线相对导航方法与多冲量相对制导律;最后,进行远距离交会任务仿真校验,结果表明编队空间机器人交会接近方法是有效的。     

ESA's Biopan 1--"Vitamin" experiment preliminary results

The purpose of “Vitamin” experiment is to study the efficiency of protective substances on three biological acellular systems aqueous solutions exposed to cosmic radiation in space. The first system “LDL”is a low density lipoprotein. The second is “E2-TeBG complexe” in which estradiol (E2) is bound to its plasmatic carrier protein, testosterone-estradiol binding globulin (TeBG). The third is “pBR 322”, a plasmid. “Vitamin” experiment was accomodated in the Biopan which had been mounted on the outer surface of a Foton retrievable satellite. The experiment was exposed to space environment during 15 days. A stable temperature of about 20 °C was maintained throughout the flight. “Vitamin” experiment preliminary results are presented and discussed.     

Mars Direct: Humans to the red planet by 1999

“Mars Direct”, is an approach to the space Exploration Initiative that allows for the rapid initiation of manned Mars exploration, possibly as early as 1999. The approach does not require any on-orbit assembly or refueling or any support from the Space Station or other orbital infrastructure. Furthermore, the Mars Direct plan is not merely a “flags and footprints” one-shot expedition, but puts into place immediately an economical method of Earth-Mars transportation, real surface exploratory mobility, and significant base capabilities that can evolve into a mostly self-sufficient Mars settlement. This paper presents both the initial and evolutionary phases of the Mars Direct plan. In the initial phase, only chemical propulsion is used, sendig 4 persons on conjunction class Mars exploratory missions. Two heavy lift booster launches are required to support each mission. The first launch delivers an unfueled Earth Return Vehicle (ERV) to the martian surface, where it fills itself with methane/oxygen bipropellant manufactured primarily out of indigenous resources. After propellant production is completed, a second launch delivers the crew to the prepared site, where they conduct regional exploration for 1.5 years and then return directly to Earth in the ERV. In the second phase of Mars Direct, nuclear thermal propulsion is used to cut crew transit times in half, increase cargo delivery capacity, and to create the potential for true global mobility through the use of CO₂ propelled ballistic hopping vehicles (“NIMFs”). In this paper we present both phases of the Mars Direct plan, including mission architecture, vehicle designs, and exploratory strategy leading to the establishment of a 48 person permanent Mars base. Some speculative thoughts on the possibility of actually colonizing Mars are also presented.     

Effect of weightlessness on posture and movement control during a whole body reaching task

Here are reported preliminary results of the “Synergy” experiment performed aboard the Russian orbital station “MIR” in July 1993 (Altaïr Mission). The experiment was carried out before, during, and after the space flight of two astronauts (S1 and S2). The duration of the flight was 21 days for S1 and 6 month for S2. The subjects were tested during preflight, inflight and postflight. The astronaut subjects were fixed on the ground by the feet. They were asked to pick up a box in front of them on the ground. Two velocities of movement and two distances of the target to be reached were tested. The movement of several small markers placed on the body was recorded on video tape.

Results show that the shape of head and hand trajectories in the sagittal plane remains roughly the same during the flight in spite of the modification of mechanical constraints. Trajectory invariance does not result in joint angular displacement invariance. These data indicate that the planning of the movement takes place in terms of head and hand trajectories rather than joint rotations as it was previously suggested for simple arm reaching movement.     

A new facility for fluid sciences: The liquid structure facility

The Liquid Structure Facility (LSF) is presently under development under ESA contract. It will be able to perform a wide range of fluid science experiments taking use of the determination of the velocity, temperature, concentration fields and the interface shape deformation. This facility will be activated by telecommands and/or manually by the crew. The key points of the LSF are the different diagnostic configuration capabilities, the modularity of the facility, and the accuracy of the control at the boundary conditions (and thus of the stimuli). The LSF is structured around four different modules:

• —the cell module which is exchangeable and is dedicated to an experiment or to a group of experiments, it allows to achieve a high accuracy level for the boundary conditions

• —the temperature control module using a liquid cooling loop which can impose a good thermal stability to the cell module

• —the diagnostic module

• —the electronic and data handling module.

The capabilities of the facility are described in terms of stimuli and diagnostic performances.     

LOCSS and its implementation on the basis of a small satellite cluster

A problem of providing users with the necessary remote sensing data in the visible and near IR spectral bands has been considered. The solution of the problem plans increase of spatial and spectral resolution for imaging from space, high periodicity of surveying the same sites on the Earth's surface and spaceborne data delivery to users in real time.

This problem solution proposed is to use a cluster of small satellites and to implement the Local Space Service (LOCSS) program. The main aspects of this concept are as follows:

• • optimization of remote sensing instrumentation parameters;

• • image data compression onboard a small spacecraft;

• • compressed data downlinking via the low rate radio channel;

• • direct reception of the image data by users at small cheap receiving stations; and

• • image data decompression and processing using personal computers and special processors.