HOUSTON (NASA PR) – Space may seem empty, but it has extreme temperatures, high levels of background radiation, minute meteors, and unfiltered sun glare. In addition, the materials and equipment on the outside of International Space Station They are exposed to atomic oxygen (AO) and other charged molecules as they orbit the Earth at the edge of our atmosphere. Only the most durable materials, equipment, and organisms can withstand this harsh environment, and scientists conducting research in the orbiting laboratory have identified some of them for a variety of potential uses.
“There are ways to test the different components of space exposure individually on Earth, but the only way to get the combined effect of all of them at the same time is in orbit,” says Mark Schumbra of Aegis Aerospace, which owns and operates the spacecraft. MISSE Aviation Facility (MISSE-FF), a platform for space exposure studies at the station. “This is important because the combined effects can be very different from the individual effects.”
Missions begin approximately every six months to MISSE-FF, which is sponsored by ISS National Laboratory. Shumbra says the trials began when the platform was installed in 2018 and will continue for the life of the space station. A former MISSE facility operating from 2001 through 2016 hosted the first station-based exposure experiments.
Some of these tasks help researchers understand how new technologies interact with the space environment. “Before using a technology on a satellite or operational vehicle, you want some confidence that it will perform the way you think it will perform in the space environment,” he says.
MISSE-FF contains high-resolution cameras that take periodic images of all items on the exposure surface and sensors to record environmental conditions such as temperature, radiation, UV exposure, and AO. All test articles are returned to Earth for post-flight analysis as well.
NASA scientists have performed multiple missions at MISSE-FF to analyze the effects of atomic oxygen and radiation on hundreds of samples and instruments.
MISSE-9for example, evaluation How polymers, composites, and coatings deal with exposure to space. For this and other MISSE missions, Kim de Groh, chief materials research engineer at NASA’s Glenn Research Center in Cleveland, is testing two primary environmental degradations. The first is how quickly the material erodes due to the AO reaction. It measures mass loss in materials exposed to space and uses that information to calculate AO corrosion yield values. These values help spacecraft designers determine whether and how thick certain materials are suitable for use.
Materials used as spacecraft insulation can become brittle in space due to the radiation and temperature cycle in orbit. This embrittlement can lead to cracks and cause problems such as overheating of a component of the spacecraft. De Groh also tests the durability of different materials to find those that resist becoming brittle.
“The ideal situation is actually to expose the samples to space, to experience all the extreme environmental conditions at the same time,” says de Grohe.
The EXPOSE-R-2 A facility from the European Space Agency (ESA) is another platform that allows scientists the opportunity to test samples in space. The European Space Agency investigations that used the facility include president And the Biomix, which exposed biofilms, biomolecules, and the extremes of space and Mars-like conditions. Extremists are organisms that can survive in conditions that are intolerable or even fatal to most forms of life.
Increased autonomy is critical for future missions that travel away from Earth and cannot rely on resupply missions. Microorganisms that tolerate extreme conditions have potential uses in life support systems for such missions, according to Daniela Pelli, a professor in the University of Rome Tor Vergata’s Department of Biology and an investigator at BOSS and BIOMEX. For example, cyanobacteria can use available resources to reform carbon (converting atmospheric carbon dioxide into carbohydrates) and produce oxygen.
During exposure on the space station, it dries Chroococcidiopsis The cells received a dose of ionizing radiation equivalent to a trip to Mars. Their response suggests that the bacteria can be transported to the planet and rehydrated on demand. The dried cells were also mixed with a simulator of Martian regolith or dust and received a dose of UV radiation corresponding to about 4 hours of exposure on the surface of Mars.
“The aim of this study was to investigate whether these cyanobacteria can repair DNA damage accumulated during travel to Mars and exposure to undiluted Martian conditions,” Bailey says.
recently published Results Suggest that they can: DNA sequencing of cells that were rehydrated after exposure did not show an increased rate of mutagenesis compared to controls grown under ground conditions. This finding increases the potential for this organism to be used to employ the resources available on site to support human settlement.
Further investigation using the EXPOSE-R-2 facility have found Signs of life in melanin-containing fungi after 16 months of space exposure. The innate pigment melanin appears to play a role in cellular resistance to extreme conditions, including radiation, and may have potential for use as radiation protection in future deep space missions. In the experiment, a thin layer of a single strain of the dyed fungi reduced radiation levels by approximately 2% and possibly by 5%.
In addition to fungi, the researchers used the ESA platform to expose the resting stages of about 40 species of multicellular animals and plants to space. EXPOSE-R IBMP Investigation. Results show up that many of these organisms have remained viable and even completed life and reproductive cycles for several generations, suggesting that future trips to other planets could take terrestrial life forms for use in ecological life support systems and to create artificial ecosystems.
As humans explore farther into space and stay there longer, testing on the space station’s exposure platforms helps ensure that the materials and systems they take with them are ready for flight.
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