The Challenge of the EuroMir 95 Technology Experiments

C. Viberti

Space Station Utilisation Division, ESA Directorate for Manned Spaceflight and Microgravity, ESTEC, Noordwijk, The Netherlands

Microbiological sampling techniques, earth-radiation- environment monitoring, gas-contaminant bio-filtering tools, multimedia communications technology, passive magnetic-levitation techniques for fluid-dynamics study, robotics-technology development, gas-sensor systems and analysis tools for human kinematics in microgravity - all were a part of the truly multidisciplinary Technology Experiments package flown aboard the record-breaking EuroMir 95 mission. Final processing and evaluation of the vast amount of data gathered from the experiments will not be completed until the end of the year - work is currently in progress at nine different centres throughout Europe - and this article therefore provides but a first glimpse of the mission's many findings and their implications for long-term manned spaceflight in the context of the International Space Station.

The experiments flown

MIRIAM-T2
This contamination monitoring experiment was designed to investigate microbial and fungine growth onboard a space station in long-term orbit. A particular objective was to verify two quick and simple methods for detecting and evaluating the microbial contamination. The first used a semi-automatic, quasi-real-time monitoring system known as a 'luminometer' which exploits the so-called 'bioluminescence reaction mechanism' (microbial biomass quantitative evaluation with adenosine tri-phosphate, or ATP, which is the major source of energy for cellular reactions). The second was based on the usual colony-forming-unit (CFU) method, but the samples were cultured directly on the sampling membranes using a simple 'mini-culture' technique.

The latter uses sterile carbon paper discs, embedded with nutrient, contained in transparent holders. Sampled membranes could simply be put into contact with the paper discs inside their container and the transparent sample holder sealed ready for later on-board analysis.

Samples were also taken for post-mission analysis on the ground to assess the effectiveness of these two new methods. Although this data analysis is still in progress, the new methods have already proved very promising in that they enabled the EuroMir 95 crew to make quick and reliable assessments of the prevailing level of biocontamination aboard the station. In fact, the preliminary assessments indicate that the number of fungine colonies on board is generally larger than expected, whilst there are fewer bacteria colony forming units than was theoretically foreseen.

The experiment equipment was engineered by Alenia Spazio (Turin, I) in collaboration with the University of Perugia (I), under contract to the Italian Space Agency (ASI).

Figure 1. View of the Mir space station from the docked Space Shuttle Atlantis

Anbre
This biomechanical motion investigation was designed to test an innovative system, based on a stretched garment fitted with elastomeric sensors, for logging the movements and postures of the crew members under microgravity conditions.

The science programme for Anbre was initially interrupted by a malfunction in the equipment's data handling unit (DHU) thought to be due to a failed microprocessor. Through the prompt collaboration of ESA's European Astronauts Centre (EAC) and ESTEC, a joint ground/ space troubleshooting effort in the first weeks of the mission resulted in nominal operation of Anbre by connecting the ESA astronaut's laptop computer to bypass the failed portion of the Anbre electronics.

A first scientific assessement of the Anbre results is currently being conducted using the experiment's memory cards brought back by the Space Shuttle (STS-76 mission) in April 1996, together with the DHU. The latter is currently undergoing a detailed inspection to establish the cause of the malfunction, which may have been due to radiation-related upset events.

The experimental equipment was developed by Verhaert Design & Development (Kruibeke, B) with scientific supervision from the Laboratoire d'Anthropologie Appliquee (Paris, F), under ESA/ESTEC contract and management.

Elite-S
This human-posture experiment, like the Anbre system, was conceived to examine the effects of microgravity on human posture, both static and dynamic. Data on motorial strategies of movement and perceptual motor relationships were also to be collected, not only in relation to human macro-kinematics , but also respiratory functions.

Elite-S was engineered, under ASI contract, by Alenia Spazio of Turin. It adapted and space-qualified a commercial product (Elite) which the Italian Centro di Bioingegneria in Milan is marketing worldwide for analysing and treating post-trauma motorial disorders, and for enhancing the dynamic performance patterns of various types of athletes.

Unlike the Anbre equipment, the Elite concept does not rely on a suit worn by the crew, but is based on the use of infrared TV cameras. These use special software to discriminate, acquire and store in real time the positions of the crew's limbs during particular movement protocols. The system records the exact positions of the various parts of the body by discretizing them into points identified by detachable skin-markers placed at precise locations on the crew member's body.

Despite the considerable amount of time required to set-up and calibrate the equipment and to perform the measurements themselves, the crew eventually managed to carry out almost all the planned kinematic protocols for the experiment. The large volume of high-quality data collected is now being analysed to build up a three-dimensional database on human posture in space and to update the human-factors analysis tools currently proposed for long-term crewed space programmes.

Biokin
Developed to validate the concept of microbial decontamination of confined atmospheres in space and verify the kinetics of such biodegradation, the Biokin equipment tested the behaviour of one particular type of bacterium, the Xanthobacter autotrophicus, within a simplified biofilter.

The early results have confirmed the suitability of the membrane separator design between the bacteria compartment and the air phase to be treated, and the possibility of inoculating the reactor in space with freeze-dried bacterial cells even after several months of storage.

The first series of such tests on board Mir in late 1995 provided valuable insight into how to improve the inoculation procedure, which was originally based on contemporary breaking of the inoculation capillaries and the substrate capillaries that contained the freeze-dried cells and the contaminant. During the mission-extension phase in 1996, the experience acquired in 1995 was capitalised upon by sending up a second flight model and having the astronaut break the capillaries sequentially, thereby greatly enhancing experiment performance and success.

Parallel experiments based on the same bacterial species catabolizing the same contaminant are now being completed back on Earth for calibration purposes, and to evaluate the kinetics of biodegradation in space versus those of the gravity-bound process on Earth.

The proven ability of selected bacterial micro-organisms to detoxify particular contaminants under microgravity conditions is an encouragement to consider extending such tests to more complex mixtures of air contaminants, aiming at the full-scale implementation of such a system within the International Space Station programme.

In fact, the Biokin air-filtering concept looks very promising not only for space environmental- control and life-support systems, but also for a new generation of ground-based air filtration systems.

The Biokin equipment was designed under ESA/ESTEC contract by the Dutch companies Stork Comprimo (Amsterdam) and Bioclear (Groningen), with support from NIVR, and built by CCM (Eindhoven)

SGS
The microgravity environment and the physical and logistical constraints of a long-term stay in the Space Station call for gas sensors that are both smaller and lighter than the bulky and costly gas-chromatograph/mass- spectrometer type equipment normally used for high-precision gas monitoring on the ground.

The purpose of the experimental Smart Gas Sensor (SGS), developed by RST (Warnemünde, D) under ESA/ESTEC contract and supervision, was to engineer and test two different types of gas-sensor arrays: one composed of organic polymers, the other based on an array of micro-balance oscillators.

Having installed the SGS box and the laptop computer in the module or space to be sampled, the crew had to activate the SGS's pump to draw ambient air to the SGS's inlet. The signals provided by the multi-element sensors were processed in real time and outputted to the portable computer for display in graphical form to the crew.

The equipment was operated extensively throughout the mission, including times when particular events might have caused the release of interesting gases, such as during the EVA phases and during the repair of a leak in one of Mir's thermal-control-system circuits.

Approximately 60 Mbytes of data were collected, covering about 40 of the mission's 180 days. Some software-related problems were reported with the laptop, again probably due to the ionising radiation environment aboard Mir.

Although final data evaluation is still in progress, the SGS was certainly proved capable of providing a complete 'smell-pattern' for the Station. It confirmed the ability of Mir's environmental control system to purify the onboard air very effectively during the crew's rest periods. Events like public-relations link-ups, with all crew members gathered in the main Mir module, returns from EVAs, station cleaning and food preparation were all detected and flagged in a timely manner by the SGS sensors.

Figure 2. The basic Mir module, now containing hundreds of equipment items associated with past and present experiments

With a view to the SGS's potential application on the International Space Station, further tuning work has to be carried out on its sensors to avoid confusion between very similar substances (e.g. butanol for ethanol, as occurred during the EuroMir 95 mission) and to equip the unit with simple visual/audio features to alert the crew quickly to any out-of-tolerance readings.

Figure 3. The T2 luminometer, after its final pre-launch inspection at the Baikonur launch site

RJC
The Robotics Joint Controller was

Figure 4. The RJC experiment box, belted into place aboard Mir developed and integrated, as part of the Italian 'Spider' programme, by Tecnospazio (Milan, I) under ASI contract. Its nominal objective was to assess the disturbances to the microgravity environment induced by various velocity and acceleration profiles of a robotic joint. The EuroMir extension programme in 1996 allowed the science team to gather additional data on the possible influence of single-event effects, disturbances in transient phases, and possible performance degradation due to long-term operation (one week).

The on-going analysis is quite complex and definitive results are not yet available, but qualitatively speaking the experimental equipment performed as expected and gathered the requisite data. A thorough scientific evaluation of these data and possible recommendations for robotic-joint technology for future space applications, including the automation of microgravity laboratories for the Space Station, will be available later this year.

REM
The purpose of the externally mounted Radiation Environment Monitoring experiment, developed at ESTEC, is to monitor the radiation environment in Mir's high-inclination orbit to improve currently available models of the charged particles that surround the Earth, many of which are based on data from more than twenty years ago and not compatible with contemporary geomagnetic field models and do not reflect well the known solar-cycle dependence.

The REM equipment was first delivered to Mir in 1994 and is still active. Its simple design is based on two independent silicon detectors with different types of shielding. The energetic particles impacting the detectors are counted and the relevant data are acquired and stored.

Regretfully, during the mission poor data return has proved a problem in terms of both quantity (a few days per month instead of daily) and quality (the data that were received contain quite some errors). Work is proceeding together with our Russian counterparts to recover the 'missing' raw data and orbital parameters in order to be able to complete a comprehensive scientific evaluation.

T10 VISC
In recent years, ESA has conducted many experimental telescience sessions in cooperation with leading European science and technology teams. The concept of having a remotely controlled video switcher and mixer to handle real-time visual information from Space Station experiments (e.g. video, audio and alphanumeric data) led to the design and development of this Video Integrated Services Controller (VISC), which was built and assembled by NTE (Barcelona, E) under ESA/ESTEC contract.

Late delivery of the final revision of the VISC video board by its US supplier did not allow digital video input mixing functions to be incorporated into the VISC flight unit for Mir. However, numerous tests involving the Station, its Russian ground centres and the ESTEC user centre have shown that the available features of the VISC multimedia communication system function well. For instance, Mir-to-ground exchanges of graphical annotations on VISC screens were successfully demonstrated, as well as ground control of onboard TV-camera outputs for downlinking.

Despite some initial shortcomings, VISC proved itself capable of enhancing telescience space operations and crew-ground interactions for the Space Station era.

Maglev
The Magnetic Levitation Experiment equipment was developed by ESA/ESTEC to demonstrate a simple and inexpensive technology for passive magnetic fluid levitation in microgravity, having as a scientific by-product interesting data on thermally-induced Marangoni convection generated within the levitation cell.

The equipment is small enough to be held in one hand. Its key lies in the generation of a levitating central force field by means of an array of permanent magnets acting on the test cell, which contains a transparent ferro-fluid and a non-magnetic levitation sample (an air bubble was the target object to be levitated).

During the mission, the Mir crew and the ground team (via the video downlink) were able to analyse visually the good stability of the above trapping mechanism, even when the bubble was disturbed by Marangoni convection flows generated at the ferrofluid/air interface by induced temperature gradients.

The concept's viability having been proved during the 1995 experiment sessions, the EuroMir programme extension in 1996 allowed further checks to be made on the levitation system's stability in the presence of transient forces applied externally to the test cell.

All in all, this experiment was a great success, especially given its extremely low development and integration costs.

LESSONS LEARNT FROM EUROMIR 95 TECHNOLOGY EXPERIMENTS

Figure 5. The EuroMir 95 crew enjoying a well-earned break in their hectic six-month work schedule

Many useful lessons were learnt both during the preparations for the EuroMir 95 mission and during the flight operations themselves, lessons that can be put to good use for ESA's participation in the International Space Station programme.

Experiments

Lesson learnt: Scientific procedures and operational protocols should be similar if not identical for analogous experiments.

Such synergy reduces the time needed for development, training and onboard operations, as well as increasing the scientific return due to better data correlation. This approach should have been implemented for the Anbre and Elite-S experiments, which were conceived, developed and operated totally independently despite the obvious analogies.

Lesson learnt: Avoid interfaces between experiments that have never been flown before.

During EuroMir mission preparation, down-linking of the Maglev and Elite-S video information by using VISC was considered. This option was eventually dropped but if it had been implemented, the Maglev and Elite-S experiments would have been negatively impacted by the problems that beset VISC (reported above).

Lesson learnt: There should be one technical coordination interface only between the ESA project and the payload funding authority, which should attend all project reviews and major work events.

During mission preparation, the T2, Elite-S and RJC funding authorities requested that all technical, scientific and operational information be sent in parallel to both themselves and the actual payload developers and engineering experts in industry. This resulted in considerable confusion. Further inefficencies occurred at the various development, integration, qualification and acceptance milestones (e.g. flight-model pre-acceptance tests) due to the limited availability of the funding-authority representative. A unique and continuous interface is mandatory for programmes of this nature.

Lesson learnt: Experiment operations should be fully rehearsed on the ground during the development phase.

For instance, the complex installation, calibration and science protocol procedures for the Elite-S experiment were not tried out in a realistic fashion until just one and a half months before launch. This resulted in major changes to the operational documentation at a very late stage and also caused unease during the acceptance testing with RSC Energia. It also resulted in substantial crew-time overruns during the mission itself.

Lesson learnt: Flight-model spares (FM2) should always be produced as recurrent units for long-term missions. When no FM2 is available, a technology model (TM) should be FM-representative although non-space-qualified. Either the FM2 or the TM should remain at the payload-developer's site.

Flight-model spares were launched during EuroMir 95 to support unplanned science sessions, as in the case of Biokin, or could have been launched if available to replace partially failed flight models (e.g. VISC and Anbre). In addition, FM2s or high-fidelity TMs are necessary to support real-time upgrading of mission objectives or for high-fidelity ground troubleshooting with the equipment experts (e.g. crash activities required for Anbre, SGS and RJC).

Lesson learnt: Experimental equipment mockups for configuration/accommodation studies can be passive models representing dimensions and crew interfaces only.

The full-scale mass mockups originally requested by RSC- Energia for the mission integration phase did not prove to be really necessary in practice; full-scale dimensional mockups only, as were eventually delivered for the technology experiments, would have been more than adequate.

Lesson learnt: Formal readiness reviews should always be held at ESA level prior to conducting acceptance tests with the responsible in-orbit system operator (i.e. RSC for EuroMir 95).

During the Technology Experiments development and acceptance phases, certain hardware and documentation was submitted to official acceptance testing with the Russian authorities before being complete or functionally ready, causing major time and efficiency losses for all concerned and resulting in time-consuming and ineffective reviews (e.g. T2 and Elite-S, Maglev and VISC).

Lesson learnt: Employ design solutions, processes and materials previously qualified and flown wherever possible in new payload development.

During the EuroMir 95 programme, some electromagnetic-compatibility testing could be skipped thanks to close design similarities with already space-proven equipment. Similarly, certain materials could be qualified on the basis of their similarity to analogous/identical alloys, elastomers or composite materials that have already been flight-qualified.

Lesson learnt: A contractually agreed payload-accommodation handbook is necessary to control payload-to-system interface requirements and simplify payload design, development and integration.

For instance, major reworking of payload documentation and hardware proved necessary in some cases due to unclear and frequently changing requirements from the Mir authorities (e.g. electrical current density requirements affecting payload electrical subsystems and wiring). This problem is de facto already solved for the International Space Station, given the very complete requirements/specifications bibliography which is kept under strict configuration control.

Human factors analysis

Lesson learnt: Do not invest heavily in such interior- design areas as the selection of space-laboratory colour schemes or the development of new crew restraint systems.

The long-term Russian experience with habitability issues, confirmed by the EuroMir flight crews, shows that much of the money being spent on human-factors analysis and prototyping is actually wasted effort because most of a module's interior is quickly covered with hardware and hanging harnesses.

In addition, unlike some current Space Station/ Columbus human-factors engineering concepts, the existing Mir crew restraints do not directly transmit crew-induced vibrations to microgravity payloads.

Crew training

Lesson learnt: High-fidelity system training should be carried out with the system-engineering model.

In the last twelve years the Russian long-term spaceflight programme has been implementing such a concept by using the Mir Space Station engineering model for both high-fidelity engineering and crew training. With appropriate facility loading and configuration control, such training can be conducted with no impact on engineering activities, thereby avoiding duplication of hardware, computer systems, manpower and infrastructures.

Lesson learnt: Integrated payload-to-system training is needed only for major experimental facilities with complex system interfaces. Such training, when deemed necessary, should be performed with the system-engineering model.

In line with the approach described in the previous paragraph, RSC-Energia and Star City have applied this concept in training crews since the early 1980s. In fact, eight of the nine EuroMir 95 experiments were trained upon in a stand-alone manner with the help of simple ground-support equipment

Figure 6. The Russian and ESA EuroMir 95 team, gathered at ESTEC in Noordwijk in September 1994 for an experiment flight-model acceptance review

Conclusions

The extremely positive outcome of the EuroMir 95 programme has to be seen not only in the light of its scientific and technological achievements, but also in the fact that as a Space Station precursor programme it has given ESA clear guidelines as to how to proceed in order to drastically enhance the design and utilisation of its contribution to the International Space Station.

Not least, various results from the above experiments that formed part of the EuroMir programme will provide added value to quite a number of new Earth-bound technologies being developed to support, and ameliorate the problems of, everyday life on our planet.

Acknowledgement

I would like to thank the colleagues who provided inputs to this article, in particular R. Binot and H. Wessels from ESTEC, and V. Cotronei from ASI.