Space Exposure Experiments
Biopan Experiment Facility
Biopan was developed in the early nineties as a multi-user experimental facility, designed to investigate the effect of the space environment on biological material as well as for carrying out material science investigations requiring exposure to the space environment. As such t he experiments in Biopan are exposed to solar and space radiation, the space vacuum and weightlessness, or a selection thereof. Optionally, the experiment temperature can be stabilised. In this way Biopan can evaluate the combined or individual effects of radiation, vacuum, extreme temperatures and weightlessness on biological samples, material specimens and electronic components.
Designed for medium-duration missions on Russian retrievable satellites, Biopan filled the gap between the Russian KNA exposure containers* and the advanced ERA facility on Eureca**. Biopan completed four successful missions on a test flight in 1992, Foton-9 in 1994, Foton-11 in 1997 and Foton-12 in 1999. A fifth attempt failed in 2002 due to a launcher failure.
The Biopan facility is installed on the external surface of the Foton descent capsule protruding from the thermal blanket that envelops the satellite. It has a motor-driven hinged lid, which opens 180° in orbit to expose the experiment samples to the harsh space environment. For re-entry, the closed facility is protected with an ablative heat shield.
The facility is equipped with thermometers, UV sensors, a radiometer, a pressure sensor and an active radiation dosimeter. If controlled, the temperature can be stabilised between 5°C and 25°C. If uncontrolled, the temperature can fluctuate from less than -35°C to more than +30°C Biopan can also be flown in a mixed mode with one set of experiments being thermally controlled, and another not. Data acquired by the sensors is stored by Biopan throughout the mission and can be accessed after flight.
For the Foton-M2 mission, the Biopan facility has had some internal modifications including a new microcontroller for more efficient data handling, a new radiometer, an increased number of temperature sensors, new software, a larger emergency battery and a new lid structure to accommodate more and heavier experiments.
The experiment packages inside are individually designed and provided by the experiment investigators themselves. These packages are mounted on simple support plates either in the bottom or in the lid of Biopan, providing a total surface area of 1080 cm 2. The maximum experiment mass is 4 kg with a maximum experiment height of 25 mm (50 mm if only the bottom or the lid are occupied). The surface area and the experiment mass are shared between four to nine different experiments.
Biopan will be hosting nine individual experiments for the Foton-M2 mission: two in radiation biology (PHOTO, YEAST II), three in radiation dosimetry (RADO, RD3-B, LETVA) and four in exobiology (ORGANICS, LICHENS, MARSTOX , PERMAFROST).
The experiment packages are hermetically sealed before launch with an internal environment maintained at 1 atmosphere in an inert atmosphere of dry nitrogen. In orbit, Biopan is first evacuated and then opened to expose the experiments to free space. One day before landing Biopan is hermetically closed by telecommand. Three to four days after landing, Biopan is returned to ESA's ESTEC facility in the Netherlands, remaining hermetically closed and evacuated. One day later Biopan is re-pressurised and opened, after which the experiments can be returned to the investigators.
* Used by ESA from 1987 until 1992 on three consecutive Bion missions for radiobiological exposure experiments.
** Exobiological Radiation Assembly on the European Retrievable Carrier; first (and only) flight 31 July 1992 - 7 August 1993.