Abstract
On July 23, 2014, the Progress cargo spacecraft 56P was launched from Baikonur to the International Space Station (ISS), carrying EXPOSE-R2, the third ESA (European Space Agency) EXPOSE facility, the second EXPOSE on the outside platform of the Russian Zvezda module, with four international astrobiological experiments into space. More than 600 biological samples of archaea, bacteria (as biofilms and in planktonic form), lichens, fungi, plant seeds, triops eggs, mosses and 150 samples of organic compounds were exposed to the harsh space environment and to parameters similar to those on the Mars surface. Radiation dosimeters distributed over the whole facility complemented the scientific payload. Three extravehicular activities later the chemical samples were returned to Earth on March 2, 2016, with Soyuz 44S, having spent 588 days in space. The biological samples arrived back later, on June 18, 2016, with 45S, after a total duration in space of 531 days. The exposure of the samples to Low Earth Orbit vacuum lasted for 531 days and was divided in two parts: protected against solar irradiation during the first 62 days, followed by exposure to solar radiation during the subsequent 469 days. In parallel to the space mission, a Mission Ground Reference (MGR) experiment with a flight identical Hardware and a complete flight identical set of samples was performed at the premises of DLR (German Aerospace Center) in Cologne by MUSC (Microgravity User Support Center), according to the mission data either downloaded from the ISS (temperature data, facility status, inner pressure status) or provided by RedShift Design and Engineering BVBA, Belgium (calculated ultra violet radiation fluence data). In this paper, the EXPOSE-R2 facility, the experimental samples, mission parameters, environmental parameters, and the overall mission and MGR sequences are described, building the background for the research papers of the individual experiments, their analysis and results.
Highlights
Space environment provides a variety of environmental extreme parameters that up to date cannot be simulated on ground
BIOMEX 2 samples from Kyiv, Ukraine, BIOMEX 6 samples from TU Berlin, and BIOMEX 7 samples from DLR, Cologne were de-integrated inside the workbench form carriers 2-2, exported via the airlock and Inside International Space Station (ISS) period launch to extravehicular activity (EVA)-39 Dark evacuation period valve open to EVA-40 Valve open to valve closed Outside space evacuation period Outside data availability Total vacuum period tray 3 Total vacuum period tray 1 Mars gas period tray 2 after second closing Outside ultraviolet. 1http (UV) irradiation period EVA-40 to EVA-42 Outside mission period EVA-39 to EVA-42 Post-outside storage in ISS tray 3 Post-outside storage in ISS trays 1 + 2 Total mission duration tray 3 launch to landing Total mission duration trays 1 + 2 launch to landing
EXPOSE-R2 accommodating four astrobiological experiments (BOSS, BIOMEX, BIODIVERSITY, and P.S.S.), the passive dosimeters and the active dosimeter R3D-R2 was launched to the ISS on July 23, 2014
Summary
Space environment provides a variety of environmental extreme parameters that up to date cannot be simulated on ground. A mission similar set of trays was provided to accommodate and expose a full flight parallel set of samples to simulated space parameters. The MGR trays were identical to the flight trays except that they were not powered They were not equipped with temperature sensors, the valves were operated manually and no active dosimeter R3D-R2 was foreseen, leaving the respective compartment 3-1 empty. Partly identical samples were accommodated in tray 1 underneath short wavelength transparent MgF2 windows and filter combinations and evacuated to space vacuum, and in tray 2 covered with window and filter combinations adjusting the LEO extraterrestrial UV spectrum to a Mars-like spectrum with wavelengths >200 nm and a Mars simulating atmosphere. Chemical samples (comets, Titan, Mars) Chemical samples (Titan) Chemical samples (meteorites) Biochips Chemical samples (interstellar medium) Chemical samples (comets, graphite) TLDs Active instrument PPO passive UV dosimeters
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