Multi-user facilities and support equipment

Multi-User Facilities and Support Equipment European

Space

Agency

The European Space Agency provides significant contributions of multiuser facilities, Payload Support Equipment (PSE), Laboratory Support Equipment (LSE) and Standard Payload Outfitting Equipment (SPOE) to support the European Space Station users community There are also research facilities provided by the Partners.

T

able I provides an overview

of those contributions and includes the currently planned Station laboratory location assignment for the pressurised payloads. The attachment site locations for the external payloads are under review. The European pressurised multi-user facilities will allow laboratory multiple users or multiple experiments to employ specific capabilities in sequenced or simultaneous operations or in accessing the experi-

ment/observation data transmitted to ground. PSE and LSE for pressurised and external payloads comprises permanently on-orbit hardware that can be shared by payloads in support of their flight accommodation and operations. SPOE for pressurised and external payloads covers qualified hardware items that may be payload-embedded to provide general operations and/or interface functions, and that pre-empt

car* Factltty on+wstw Dtsotbution unit

Fjgufe 1. The Material Science Laboratory will investigate solidification physics, crystal growth with semi-conductors, thermophysical properties and the physics of liquid states. (Dot. ESA)

the need for users to undertake their own development.

Among the European pressurised multi-user facilities in the US laboratory Material Science Laboratory The Material Science Laboratory (figure I) offers a multi-user capability to support scientific research in solidification physics, crystal growth with semi-conductors, measurement of thermophysical properties and the physics of liquid states. MSL occupies about half of an ISPR (International Standard Payload Rack) in the US Lab, and one ISPR in the Columbus Laboratory. The two MSL versions are identical except for minor rack interface differences. Each MSL comprises a core element consisting of a sealed process chamber in which interchangeable furnace inserts are hosted. These inserts process the samples. The sample cartridges are manually loaded into one of the furnaces. The furnace can be moved over the sample cartridge to displace the thermal gradients. Diagnostic systems provide scientific data on the facility and sample cartridge during operations. As the fur-

Automatic Stowaye

Automatic Temperature C,ontrolled Stowaoe I ATCS’s

for manual operations on Experiment Container samples. The glovebox, working under negative pressure, preempts any possible contamination to the laboratory atmosphere.

Ambient (AAS)

i

Fluid Science laboratory

A”tom&

Figure

2. Biolab

will support

biological

naces are modular, they can be upgraded or replaced according to utilisation needs. Additional MSL units complete the accommodation and operational interfaces to the laboratory.

Section

i Manual

research.

(Dot.

Sectvan

ESA/D, Ducros)

Among the European pressuris0d multi-user facltSttes In the Columbus Laboratory

supporting experiment sample test analyses. A capability for the visualisation of images is at hand. The atmospheric environment of the Experiment Container may be adjusted during centrifuge operations. Automatic temperature-controlled and ambient temperature stowage units are available for storing Experiment Container samples. A Biolab glovebox provides a clean, controlled and enclosed environment

Biolab is a multi-user facility (figure 2) designed to support biological experiments on micro-organisms, animal cells, tissue cultures, small plants and small invertebrates. Biolab occupies one ISPR. The facility features an incubator equipped with centrifuges offering controlled levels of accelerations. Experiment samples are contained in versions of two Experiment Containers placed on the centrifuges. The Experiment Containers can be handled automatically by the Biolab Handling Mechanism. Independent analysis instruments are available for

Figure

3. Principal

features

The Fluid Science Laboratory (figure 3) is a multi-user research capability to study dynamic phenomena of fluid media in the absence of gravitational forces. FSL occupies one ISPR. For facility users, the most significant FSL element is the Facility Core Element that houses the central experiment module, the optical diagnostics module and the standardised Experiment Containers (ECs). The central experiment module is divided into two parts: 1. contains the suspension structure for the ECs, including all the functional interfaces and optical equipment, and is designed to be pulled out from the rack to allow insertion and removal of the EC; 2. contains all the diagnostic and illumination equipment and its control electronics to command and monitor the electro- and opto-mechanical components. The optical diagnostics module houses the equipment for visual and interferometric observation, their related

of the Fluid Science

laboratory

(Dot.

ESA)

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control electronics and the attachment points and interfaces for front-mounted cameras. The ECs provide the exchangeable receptacle to host the experiment fluid cells as well as any process stimuli and specific user diagnostics, and their supporting container electronics. The FSL can be operated in fully automatic or semi-automatic modes by the flight crew, or in a remote-control mode from the ground (telescience).

European external facilities on US Express Pallets Under a barter agreement, ESA has access to five Express Pallet Adapters on US Express Pallets. For these opportunities, ESA made an Announcement of Opportunity, in 1997 and selected five Express Pallet payloads: ACES, EUTEF, EXPORT, FOCUS, and SOLAR.

The Express Pallet system The Express Pallet system @gure 4) allows payloads to be mounted at external sites on the ISS Truss structure. This US-provided Pallet system will be launched and retrieved by the Space Shuttle. The Pallets, which will be attached at specific locations on the Truss, can be zenith- or nadir-facing, allowing them to carry instruments requiring solar or celestial viewing (zenith) or Earth viewing (nadir). The Express Pallet will house six Adapters, each capable of carrying up to 225 kg of payload on a 1 m2 mounting surface. EM’s instruments will be grouped to fully occupy Adapters: the SOLAR, EXPOSE/SPORT (EXPORT) and EUTEF pachages are zenith-oriented, while ACES and FOCUS are nadiroriented. It is planned that two of the three Adapters will be exchanged during the three-year mission.

Figure 4. The Express Pallet, carrying (Doe. ESA/D. Ducros)

six ExPAs, mounted

on the ISS Truss.

The first hve European payloads ACES - an Atomic Clock Ensemblein

Space

The core of this project (seefigure 5) is a laser-cooled caesium atomic clock (‘Pharao’), which exploits the microgravity conditions onboard the Space Station. The investigator team includes researchers belonging to the group that received the Nobel Prize for Physics in 1997. Pharao will improve clock frequency stability and accuracy by a factor of 100 compared with the best measurements currently achievable on Earth, opening up new opportunities in various fields of fundamental research and applications. This ultra-precise measurement of time will allow relativistic measurements and tests, applications in atmospheric physics and geodesy, navigation and advanced telecommunications. The ACES Principal Investigators are Prof. C. Salomon from the Ecole Normale Superieure, Paris and Prof. A. Clairon of the Laboratoire du Temps et des Frequences, Paris. A Swiss hydrogen-maser clock provided by Dr. L.G. Bernier from the Observatoire Cantonal de Neuchatel, Switzerland, will serve as a reference AIR

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Figure 5. The ACES concept; Pharao is the laser-controlled atomic clock and the hydrogen maser serves as the reference clock. (Dot. ESA)

6. The Technology Exposure Facility (TEF)supports space technology research and developmen t. (Doe. ESA) Figure

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Facilities ., .,. clock. The important time transfer by laser link will be realised from the Observatoire de la CBte d’Azur in Grasse, France, with Dr. Samain and Dr. l? Fridelance.

SPORT

EUTEF- The European Technology Exposure Facility

Figum 7. a) The Sky Polarisation Observatory (SPOR7) will survey the polarisation of the diffuse cosmic background radiation; b) The EXPOSE unit (mounted on the Coarse Pointing Device) will expose biological specimens to the space environment. (Dot. ESA)

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EUTEF is a multi-user support facility yigure 6) that will be developed under the auspices of ESA’s Manned Spaceflight and Microgravity Directorate. It will provide modular accommodation for a variety of technology payloads requiring space exposure. It incorporates a materialproperties laboratory allowing periodic onboard measurements of surface degradation and a comprehensive environment-monitoring package to characterise the ISS space environment, including high-energy cosmic radiation, the natural and ISS-Induced plasma environment, atomic-oxygen concentration, etc. An ASI-provided robot arm, to be incorporated with a tele-operated intelligent gripper for payloads, will allow the servicing of payloads, the exchange of exposed material within EUTEF modules, or the pointing of samples to a specific environment. Several proposed EUTEFF experiments - from France, Germany, the United Kingdom, the Netherands, Italy and Spain - have already been selected. Industrial initiatives to qualify advanced and innovative sensors, components or subsystems have been selected with the highest priority. One example in this respect is the testing of a high-temperature super-conductor for communications. EXPORT - consisting of EXPOSE SPORT

Figure 8. FOCUS will de tee t terrestrial high-temperature events, such as vegetation fires. (Dot. ESA)

Figure 9. The Solar Monitoring Observatory (SOLAR) will measure the sun 3 total and spectral radiance. (Dot. ESA)

EXPOSE - Eight exobiology experiments have been selected for accommodation on an exposure unit oriented towards the Sun (figure 7). A range of organic molecules and micro-organisms will be exposed unshielded to solar ultraviolet radiation and the space environment (vacuum, cosmic

international___- Space_--Station ---. radiation). This study of photochemiCal, processes will support conclusions as to the origin and evolution of life, and on the survival capability of micro-organisms in space. SPORT - will measure the polarisation of the sky diffise background radiation in unexplored wavelength range between 20 and 70 GHz. In this spectral range, the galactic synchrotron radiation is the strongest source of polarised emission; however, the detection of small contributions from the linear polarisation of the cosmic microwave background radiation would be of great interest for modern cosmology. FOCUS - lnfelligenf Fire Defection Infrared Sensor System

FOCUS will detect, from the ISS orbit, and analyse high-temperature events such as vegetation tires and volcanic eruptions (tip-e 8) Large forest and Savannah fires, as well as volcanic activities, have global atmospheric consequences (e.g. greenhouse effect, cloud generation, climate change) and the measurements onboard the Station will contribute to the classification, atmospheric composition determination and geocoding of the data, which will be transmitted to a worldwide scientific, application-oriented and preoperational user community.

Figure 10. The Global broadcast data and

Transmission high-accuracy

Services (GTS) system, which time signals.(Dot. ESA)

will

SOLAR- A Solar Monitoring Observatory

The main objective of this experiment is to measure the solar spectral irradiante with unprecedented accuracy. Apart from the scientific contributions for solar and stellar physics, knowledge of the ‘solar constant’ and its variations is of great importance for atmospheric modelling, atmospheric chemistry and climatology. The SOLAR observatory @gure 9) consists of three instruments, which complement each other and together cover the wavelength range 17-3000 nanometres (nm), in which 99% of solar energy is radiated. They are:

Figure 11. Left) Matroshka will be mounted on the outside of the Russian Service Module; right) Mathematical mode/ of the Matroshka human torso/head dummy (Dot. ESA) AIR

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Multi-User - SOVIM (Solar Variable & Irradiance Monitor); - SOLSPEC (Solar Spectral Irradiance Measurements); -SOL-ACES (SolarAuto-Calibrating EUV/UV Spectrophotometers), a new instrument which will cover the solar spectral h-radiance range from 17 to 220 nm. The three instruments are mounted on a Coarse Pointing Device, which provides Sun-pointing for about 13 minutes per orbit.

ESA’s use of the Russian Segment The Russian Segment of ISS is an attractive place to fly external payloads, and two European payloads are selected, the ‘Global already Transmission Services System’ (figure 10) and Matroshka @gure 11). The Gtoba/ Tmnsmission Services (GTS) System

As a continuation of the recent successful cooperation between ESA and Russia on the Mir station, both sides have agreed to implement GTS as a Euromir-E replacement activity. GTS is a relatively small payload that will transmit highly accurate time and coded data signals for dedicated receivers on the ground. The GTS experiment uses a transmitter accommodated onboard the ISS for signal distribution via an externally mounted antenna with a transmission cone half-angle of approximately 70 deg on the Russian Service Module. The signals transmitted - at two dedicated frequencies in the 400 MHz and 1.4 GHz ranges - can be received for 5-12 min several times per day by

Facilities ground receivers with sufficient sensitivity. The same services - specifically the highly accurate time signal - will be available through dedicated connections to users accommodated on-board the Russian Segment. Applications foreseen include: - accurate time receipt and automated local time conversion for mobile users on the ground (e.g. wrist watches); - car theft-protection (electronic car keys); - coding and re-coding of electronic cards (clip cards, smart cards, credit cards). The GTS experiment, which will begin operating approximately six months after launch of the Russian Service Module, will last at least two years. The Matroshka-payload

The Matroshka experiment (fisure II) aims to measure the radiation that an astronaut faces during Extra Vehicular Activity (EVA). Knowledge of the radiation doses to which sensitive body organs are exposed during long EVAs is an important prerequisite for radiation risk assessment. TheAMS experiment

A further important external payload, selected by NASA, but with an impor-

tant European scientific contribution, is the Alpha Magnetic, Spectrometer (AMS) experiment. This payload is designed for the study of anti-matter and missing matter. To be located on an ISS Express Pallet in a zenithpointing position, the AMS is an international collaboration between China, Finland, Germany, Italy, Russia, Switzerland, Taiwan and the United States. The team is led by Nobel Prize winner Prof. S.C. Ting. The key scientific objective is to search for antimatter, basically antihelium and anti-carbon, with a detector sensitivity 104 to 105 times better than current limits. The Big Bang theory of the origin of the Universe requires matter and anti-matter to be equally abundant at the very hot beginning. The ASM payload is expected to detect a few anti-carbon nuclei per week if the present theory of the Big Bang is correct. n

REFERENCES [l] Document ESA BR- 137, February 1999. [2] Andresen R.D., Peters G., European external payloads selected for early utilisation on the International Space Station, Document ESA, June 1999.