Reactivation of Microbial Strains and Synthetic Communities After a Spaceflight to the International Space Station: Corroborating the Feasibility of Essential Conversions in the MELiSSA Loop

To sustain human deep space exploration or extra-terrestrial settlements where no resupply from the Earth or other planets is possible, technologies for in situ food production, water, air, and waste recovery need to be developed. The Micro-Ecological Life Support System Alternative (MELiSSA) is such a Regenerative Life Support System (RLSS) and it builds on several bacterial bioprocesses. However, alterations in gravity, temperature, and radiation associated with the space environment can affect survival and functionality of the microorganisms. In this study, representative strains of different carbon and nitrogen metabolisms with application in the MELiSSA were selected for launch and Low Earth Orbit (LEO) exposure. An edible photoautotrophic strain (Arthrospira sp. PCC 8005), a photoheterotrophic strain (Rhodospirillum rubrum S1H), a ureolytic heterotrophic strain (Cupriavidus pinatubonensis 1245), and combinations of C. pinatubonensis 1245 and autotrophic ammonia and nitrite oxidizing strains (Nitrosomonas europaea ATCC19718, Nitrosomonas ureae Nm10, and Nitrobacter winogradskyi Nb255) were sent to the International Space Station (ISS) for 7 days. There, the samples were exposed to 2.8 mGy, a dose 140 times higher than on the Earth, and a temperature of 22 degrees C +/- 1 degrees C. On return to the Earth, the cultures were reactivated and their growth and activity were compared with terrestrial controls stored under refrigerated (5 degrees C +/- 2 degrees C) or room temperature (22 degrees C +/- 1 degrees C and 21 degrees C +/- 0 degrees C) conditions. Overall, no difference was observed between terrestrial and ISS samples. Most cultures presented lower cell viability after the test, regardless of the type of exposure, indicating a harsher effect of the storage and sample preparation than the spaceflight itself. Postmission analysis revealed the successful survival and proliferation of all cultures except for Arthrospira, which suffered from the premission depressurization test. These observations validate the possibility of launching, storing, and reactivating bacteria with essential functionalities for microbial bioprocesses in RLSS

Angular dependence of track-etch detector HARZLAS TD-1

Track-etched detectors are commonly used also for radiation monitoring onboard International Space Station. To be registered in track-etched detectors, the particle needs to meet several criteria—it must have linear energy transfer above the detection threshold and strike the detector’s surface under an angle higher than the so-called critical angle. Linear energy transfer is then estimated from calibration curve from the etch rate ratio V that is calculated from parameters of individual tracks appearing on the detector’s surface after chemical etching. It has been observed that can depend on the incident angle and this dependence can vary for different detector materials, etching and evaluating conditions. To investigate angular dependence, detectors (HarzlasTD-1) were irradiated at HIMAC by several ions under angles from 0◦ to 90◦. The correction accounting not only for critical angle but also for dependence of V on the incident angle is introduced and applied to spectra measured onboard International Space Station

Radiation protection of aircraft crew: publicly available database of measurements with the silicon spectrometer Liulin on board aircraft

Annual effective doses of aircrew from occupational exposure are typically up to 6 mSv, depending on the number of flight hours, route locations, and solar activity. In many cases, these doses exceed the limit for public exposure to ionizing radiation and thus ICRP recommended their monitoring. Radiation fields at aircraftaltitudes are complex and difficult to measure experimentally. For this reason, the doses are estimated via computer codes that take into account flight parameters like aircraft location and altitude, and solar activity. It is generally accepted, that these calculations should be periodically verified by measurements. Precisemeasurements with tissue equivalent proportional counters are typically short-term only as these detectors are bulky and have only limited battery life. For long-term measurements, which are needed to cover the whole 11-year solar cycle, the silicon spectrometer Liulin is better suited. Liulin is an active dosimeter which records energy deposition events occurring in the semiconductor unit, and – if appropriately calibrated – it estimates neutron and non-neutron component of the ambient dose equivalent. This paper presents a database of long-term measurements performed on board aircraft with the Liulin detector. The measurements started in 2001. For one run, Liulin was placed in the cabin of a Czech Airlines aircraft for approximately 50 days. So far 28 runs were performed, i. e. about 3 500 flights and almost 20 000 flight hours. Flights were flown from Prague to destinations with vertical cut-off rigidities ranging from 1 GV to 17 GV. The most frequent were transatlantic flights from Prague to New York and to Canada. The database comprises more than 105 records where each record contains information on: energy deposition spectra, absorbed dose rates and dose equivalent rates measured with Liulin, date and time, geographic coordinates and altitude. The data are available on the Internet and can be used for instance for verification of computational programs routinely used for estimation of aircrew exposure to cosmic radiation.14th International Congress of Radiation Researc

Comparison of Cosmic Radiation Detectors in the Radiation Field at Aviation Altitudes

An assessment of the exposure of aircrew and passengers to the complex radiation field at aviation altitudes has been a challenging task and a legal obligation in the European Union for many years. The response of several radiation measuring instruments to this radiation field was investigated by different European research groups within the framework of the CONCORD campaign (COmparisoN of COsmic Radiation Detectors) in the Radiation Field at Aviation Altitudes. We measured dose rates at four positions in the atmosphere in European airspace, two altitudes at two locations respectively, under quiet space weather conditions during joint measuring flights with the twin-jet research aircraft Dassault Falcon 20E operated by the DLR flight facility Oberpfaffenhofen. The results show a very good agreement between the readings of the instruments of the different research groups as well as for the comparison of the corresponding average values with PANDOCA model calculations

CONCORD: comparison of cosmic radiation detectors in the radiation field at aviation altitudes

Space weather can strongly affect the complex radiation field at aviation altitudes. The assessment of the corresponding radiation exposure of aircrew and passengers has been a challenging task as well as a legal obligation in the European Union for many years. The response of several radiation measuring instruments operated by different European research groups during joint measuring flights was investigated in the framework of the CONCORD (COmparisoN of COsmic Radiation Detectors) campaign in the radiation field at aviation altitudes. This cooperation offered the opportunity to measure under the same space weather conditions and contributed to an independent quality control among the participating groups. The CONCORD flight campaign was performed with the twin-jet research aircraft Dassault Falcon 20E operated by the flight facility Oberpfaffenhofen of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR). Dose rates were measured at four positions in the atmosphere in European airspace for about one hour at each position in order to obtain acceptable counting statistics. The analysis of the space weather situation during the measuring flights demonstrates that short-term solar activity did not affect the results which show a very good agreement between the readings of the instruments of the different institutes

Liulin silicon semiconductor spectrometers as cosmic ray monitors at the high mountain observatories Jungfraujoch and Lomnický stit

Currently, most cosmic ray data are obtained by detectors on satellites, aircraft, high-altitude balloons and ground (neutron monitors). In our work, we examined whether Liulin semiconductor spectrometers (simple silicon planar diode detectors with spectrometric properties) located at high mountain observatories could contribute new information to the monitoring of cosmic rays by analyzing data from selected solar events between 2005 and 2013. The decision thresholds and detection limits of these detectors placed at Jungfraujoch (Switzerland; 3475 m a.s.l.; vertical cut-off rigidity 4.5 GV) and Lomnicky stıt (Slovakia; 2633 m a.s.l.; vertical cut-off rigidity 3.84 GV) highmountain observatories were determined. The data showed that only the strongest variations of the cosmic ray flux in this period were detectable. The main limitation in the performance of these detectors is their small sensitive volume and low sensitivity of the PIN photodiode to neutrons