SENAT
Report n° 230 (2006-2007) by M. Christian GAUDIN, Senator (for the parliament office for the evaluation of scientific and technological choices)
Disponible au format Acrobat (12 Moctets)
V. PREPARING THE SPACE MISSIONS IN ANTARCTICA
Due to Antarctica's extreme conditions and the organization of the bases, it can be used to prepare for the space missions. It is also necessary to carry out in the polar regions operations to prepare and verify the satellite-based and robotic missions.
A. PREPARING AND VALIDATING THE SATELLITE MISSIONS
1. Space and the polar regions: preparation complementarity
Your rapporteur has already shown above the importance of the complementarity between Antarctica and outer space in terms of astronomic research and scientific space missions.
What is true for astronomy is equally true for the preparation of observation missions. Antarctica's extreme climatic conditions and, in particular, the cold and electromagnetic environment make this continent a very useful zone for the testing of equipment - robotic or otherwise - destined for space or for other planets. Indeed, this equipment must be able to withstand extreme conditions similar to those of Antarctica. Equipment that doesn't function in Antarctica has little chance of functioning in space.
Therefore, IPSL is currently carrying out, via the Centre d'études des environnements terrestres et planétaires (Research Centre for Terrestrial and Planetary Environments), a long-term test on the stability of a triaxial, flux-valve magnetometer destined to be installed on the surface of Mars. The magnetometer is subjected to thermal variations of between -70 and -30°C, comparable to those it can expect to encounter on Mars. In addition, these performances can be compared to those recorded at the observatory, which is located in a much more stable environment.
Within the framework of the Arena network, French researchers have also proposed measuring the frozen particles and electric field in Dome C's boundary layer to predict the impact of these phenomena on equipment sent into space . The measurements would be made using AIRS electric antenna of the vertical electric field, the atmosphere's electrical conductivity, and the dispersal and distribution of charged ice particles.
2. Validating on the ground observations made from space
Despite the spectacular progress made in satellites, projects for the preparation and validation of the collected information must still be carried out. This is particularly true regarding the evaluation of ice, whether inlandsis or sea ice. Your rapporteur would like to here cite two examples characteristic of this work in preparation for the launch of the Cryosat satellite.
· Calibrating Cryosat on sea ice
The Electromagnetic Bird (E-M Bird) instrument of the Alfred Wegener Institute (AWI) will be deployed during the International Polar Year, during the mission carried out by Jean-Louis Etienne at the North Pole.
This instrument is designed to be placed between 15 and 20 m above the ice shelf, in order to furnish a continuous profile of its thickness. It consists of a laser altimeter that can be used to measure the distance between the instrument and the upper surface and of an electromagnetic transceiver which, via low-frequency induction, allows scientists to measure the sub-surface depth.
In addition to the centre of scientific interest consisting of studying the changing extent and thickness of the boreal ice shelf, the objective of this mission is to establish a reference value that could then be compared to that obtained by the Cryosat satellite via its laser altimeter, whose principle innovation will be its taking into account all the discontinuities in the ice to produce a much more precise mass assessment.
· Calibrating Cryosat on continental ice
This mission was partially carried out by a German team of the AWI. It used an airborne radar: the Airborne SAR Interferometric Radar Altimeter System (ASIRAS). One point calling for clarification was the impact of discontinuities in the snow (in particular those of the upper layer) on the radar echo. The instrument's calibration was carried out on a perfectly familiar terrain, a runway, to allow for a precision of some 2 cm.
Several missions were carried out from March to the end of September 2004 at Svalbard and in Greenland. These missions allowed scientists to obtain a profile of the Greenlandic icecap in two areas and to a depth of some 20 m. As a reference point, a reflective corner was installed such as those used for satellites. A British team confirmed the measurements on the ground via a sledge-mounted instrument pulled by a man.
This calibration programme will be continued by a Svalbard mission in 2007, then in Antarctica in 2008. There will then follow verification missions after the launch of Cryosat in 2009 or starting in 2010.
B. PREPARING MANNED SPACE FLIGHTS AND MOON OR MARS-BASED STATIONS
The conditions of isolation experienced by the personnel of the Antarctic stations are the most similar on Earth to those encountered in space: complete isolation of up to 9 consecutive months; night; extreme cold and therefore confinement; living in small communities or even, for Concordia, an organization similar to that planned for a moon or Mars-based station. Therefore, the bases offer a rare opportunity to carry out research programmes which otherwise would have to be carried out in caissons.
1. Concordia - a unique research site
In this respect, Concordia is truly the world's most valuable station for the space agencies. While the permanent coastal stations' climate, geographic location and organization (scattered buildings, at times high number of winter residents) certainly make them interesting locations for carrying out behavioral research, their conditions are still very different from what we could expect to encounter onboard a space vessel or station. In addition, several of these Antarctic stations must deal with a growing number of tourists.
The only other permanent stations located in the Antarctic interior - Vostok and South Pole - are not as interesting for such research. Indeed, the main disadvantage of the South Pole station is its great size. It is therefore not comparable to what could exist in the near future - it rather resembles what could exist on the moon in a few decades. As for Vostok, this station suffers from a certain rusticity which makes this type of research difficult. Both of these bases also have the disadvantage of being old stations which no longer allow for contamination studies set at a level of 0 contamination.
However, Concordia has all the necessary conditions: a layout similar to what could exist in space; a reduced personnel limited to 15 persons; a multi-national team (Franco-Italian); and a recent station , in which medical and biological studies have been carried out since its opening.
2. Studying behaviour in an extreme environment
The first field of study is that of human behaviour in conditions of confinement.
An initial research programme studies the psychosocial adaptation of a multi-cultural group in a closed, isolated environment: strategies for "coping"; the influence of the environment; group dynamics; and leadership phenomena. The delicate equilibrium of these stations can rapidly deteriorate. The team can become obsessed with a relatively small event, leading to a deterioration of the station's atmosphere for a much longer period of time than normal given the absence of more important events liable to divert the team's attention. Similarly, as regards leadership, the scientific teams at the Antarctic stations behave very differently than the military crews of nuclear submarines. Hierarchy, discipline and task distribution at the stations is much less rigid, which can complicate the exercise of authority.
A second programme specifically studies body language, or ethology. The ethological approach focuses on the co-adaptation process of the members of the research team, whose socializing is restrained by extreme conditions. It studies how the individuals occupy space in the collective activity areas by monitoring changes in such behaviour over time. It sheds light on critical moments during the mission and cycles of behavioural change that can be identified by typical behaviour.
In addition to having theoretical repercussions, this research should help prevent serious crises from appearing within the teams by predicting such problematic situations and aiding in their resolution by referring to model-data.
These are based on various methods for gathering information, from questionnaires to cameras, which are used very sparingly. Indeed, the teams are reluctant to take part in studies that are too intrusive and which do not respect their privacy and are difficult to deal with in a context of confinement, where one major type of behaviour in the middle of the austral winter is that of withdrawing into a reconstructed private space and reducing one's interactions with the other team members. This undoubtedly explains why the biggest celebration in Antarctica is that of mid-winter, which has always been a cause of great rejoicing.
The particularly delicate nature of such research also explains why the directors of several foreign research stations have opposed such studies. They fear that such studies could have serious consequences on their teams, especially as outside intervention is impossible during the austral winter. They therefore prefer to rely on very strict procedures for selecting their teams' members and on their own experience as directors, rather than the integration of teams of specialists in psychology or behavioural studies.
3. Physiological studies
In addition to behavioural studies, the Concordia station allows for the carrying out of several important physiological studies on populations subjected to very particular conditions.
First and foremost, studies on biological contamination are carried out at Concordia; these studies seek to understand how pathogens develop in a closed environment, based on an initial situation of zero contamination. Concordia is an excellent site for such research, because nothing - or almost nothing - can survive outside the station due to the extreme temperatures. Thus, a parallel can easily be drawn between Concordia and long-term space flights or space-based stations , in which, from an initial "virgin" situation, a new living environment would also develop due to contamination. This research is therefore of great interest.
Another example of research carried out at Concordia is studying the adaptation over time to conditions unique to the site. Indeed, Dome C is located at an altitude of more than 3,000 m, equivalent to an altitude of more than 4,000 m in a very dry and cold atmosphere. It is therefore possible to carry out studies on the adaptation to hypoxia in both the first days of wintering and during this entire period.
C. TESTING EXPLORATION MATERIAL
Similarly, the space agencies have recognized the interest of using either the environment or the research stations in Antarctica to test equipment destined for space-exploration missions.
1. American examples and projects
NASA and the NSF have for many years recognized the interest of using Antarctica to test materials liable to be used in exploring the solar system.
Indeed, the McMurdo station is located near a few dry valleys in Antarctica. These valleys are absolutely exceptional sites for a continent covered on average by 2,000 m of ice.
This situation is explained by the sites' morphology and climate. They are completed protected - even over-flights are prohibited without express permission. A few, in particular the high Beacon Valley, have glaciers covered with blocks of rock, producing formations that are very unique on Earth and are somewhat similar to sites on Mars (the Mars Crater Wall).
These sites were used for the testing of lunar rovers. More recently, they have been used to test Mars rovers.
One of NASA's planned futuristic projects will use sub-glacial lakes in Antarctica to test in near-real conditions a cryobot/hyrdobot capable of penetrating the ice covering Europa, one of Jupiter's satellites, or the icecaps of other celestial bodies in the solar system.
All the necessary conditions have yet to be met, because the researchers do not yet have the technology to allow them to avoid any risk of contaminating these lakes.
2. European perspectives
For Europe, as well, Antarctica can offer new opportunities for testing materials before they are sent into space, in particular towards Mars.
Today, the most important experiment is Concordia's water-treatment system . Indeed, the station's similarities with a space station, or the conditions of isolation similar to those of a long-term space flight , have attracted the attention of ESA . Another similarity is Concordia's obligations concerning the treatment of waste generated by polar operators, who must remove their waste from Antarctica. They also would like to determine the most effective in situ solutions, to save on logistics.
An effective solution must also be found for the production of drinking water. Contrary to popular opinion, water is a problem in Antarctica, because most bases do not have an easily accessible source of fresh (liquid) water. The usual techniques consist of producing fresh water from ice, using either a melting machine or a well. The well technique consists of drilling down to the level at which snow becomes ice and then injecting warm water to melt the ice. But this necessitates often changing the pumping site. The melting-machine technique consists of making a daily collection of snow according to the level of consumption; this can become a real chore, because 4 to 5 m 3 of snow is needed to produce 2 m 3 of water. A system for the recycling of water is therefore a very interesting alternative.
Concordia's water-recycling system is based on the separate treatment of its "grey" and "black" wastewaters . The grey wastewater includes water used for both cleaning (body, ground, dishes, clothing) and cooking.
The black wastewater includes organic waste (human excrement, leftovers from meals, expired food) and sludge produced by the grey wastewater. To ensure their separation, two vacuum wastewater collection systems have been installed.
The tests also allowed for the identification of soaps and cleaning products suited to the recycling system, as well as the correct doses. Therefore, Concordia doesn't offer a choice of shower gels!
All types of waste have been modeled according to the population liable to be present at the station: from 15 to 70 persons. 2.4 m 3 of grey wastewater must therefore be treated.
The treatment of grey wasterwater is carried out in a tank that can contain one day's wastewater. The wastewater is continually stirred. The water is passed through four filters, from coarse to ultra-fine filters (ultrafiltration - nanofiltration), then two stages of reverse-osmosis remove the salts from the treated products. After ultrafiltration, 90% of the water is recovered. The remaining 10% is treated with the black wastewater.
This system was put into service in March 2005. It had first been tested at a secondary school with a boarding school in the spring of 2004. Its design was completed in July 2002 and its construction was finished at the end of 2003.
The system for treating black wastewater also uses a tank capable of containing up to one day's waste production (1.5 m 3 ). The water is continuously stirred and is also filtered to eliminate any abrasive particles liable to damage the membranes. An anaerobic reactor is then used to avoid any exchange with the outside environment, such as injections of air and ejections of unpleasant-smelling vapour into the atmosphere. The reactor consists of three levels: liquefaction (3 days), methanogenization and nitrification (1.5 days). The water produced by the system is sent to the grey wastewater system, while the remaining product is frozen, sent to the coast and scattered at sea.
Via these different examples, your rapporteur would like to underline :
- the growing complementarity between space-based research - with regard to its scientific and technological components - and research in a polar environment;
- the development of a new body of research and activities;
- their serving as precursors for solar-system exploration programmes.
Thus, these programmes - at once complementary, innovative and ground-breaking - merit real support, because they are also essential for the success of our space missions.