Most of the diverse elements in the Universe come from supernovae. We are, quite literally, made of the dust of those long-dead stars and other astrophysical processes. But the details of how it all comes about are something astronomers strive to understand. How do the various isotopes produced by supernovae drive the evolution of planetary systems? Of the various types of supernovae, which play the largest role in creating the elemental abundances we see today? One way astronomers can study these questions is to look at presolar grains. These are dust grains formed long before the formation of the Sun. Some of them were cast out of older systems as a star fired up its nuclear furnace and cleared its system of dust. Others formed from the remnants of supernovae and stellar collisions. Regardless of its origin, each presolar grain has a unique isotopic fingerprint that tells us its story. For decades, we could only study presolar grains found in meteorites, but missions such as Stardust have captured particles from comets, giving us a richer source for study. Observations from radio telescopes such as ALMA allow astronomers to look at the isotope ratios of these grains at their point of origin. We can now study presolar grains both in the lab and in space. A new study compares the two, focusing on the role of supernovae. Pair of presolar grains from the Murchison meteorite. Credit: Argonne National Laboratory, Department of Energy What they found was that the physical gathering of presolar grains will be crucial to understanding their origins. For example, Type II supernovae, also known as [core-collapse supernovae,](https://briankoberlein.com/post/supernovas-tale/) are known to produce Titanium-44, which is an unstable isotope. Through decay processes, this can create an excess of Calcium-44 in presolar grains. But grains cast off from young star systems also have a Calcium-44 excess. In the first case, the grains form with titanium, which then decays to calcium, while in the second case, the grains form with calcium directly. We can’t distinguish between the two just by looking at the isotope ratios. Instead, we have to look at the specific distribution of Calcium-44 within the grain. The team found that using nanoscale secondary ion mass spectrometry (NanoSIMS) they could distinguish the origin of grains found in meteorites. Similar complexities are seen with isotopes of silicon and chromium. Overall, the study proves that we will need much more study to tease apart the origins of the presolar grains we gather. But as we better understand the grains we gather here on Earth, they should help us unravel a deeper understanding of how elements are forged in the nuclear furnaces of large stars. Reference: Liu, Nan, et al. “Presolar grains as probes of supernova nucleosynthesis.” arXiv preprint arXiv:2410.19254 (2024). The post Learning More About Supernovae Through Stardust appeared first on Universe Today.

While new rockets and human missions to the Moon are in the press, NASA is quietly thinking through the nuts and bolts of a long-term presence on the Moon. They have already released two white papers about the lunar logistics they’ll require in the future and are now requesting proposals from companies to supply some serious cargo transportation. But this isn’t just for space transport; NASA is also looking for ground transportation on the Moon that can move cargo weighing as much as 2,000 to 6,000 kg (4,400 to 13,000 pounds.) In a recent press release, NASA asked U.S. industry to submit proposals for logistics ideas and solutions to help the agency land and move cargo on the lunar surface during the upcoming Artemis missions. “NASA relies on collaborations from diverse partners to develop its exploration architecture,” said Nujoud Merancy, deputy associate administrator, strategy and architecture in the Exploration Systems Development Mission Directorate at NASA Headquarters in Washington. “Studies like this allow the agency to leverage the incredible expertise in the commercial aerospace community.” In the two white papers, NASA outlined the “gaps” they have lunar logistics and mobility as part of its Moon to Mars architecture.  In the first paper, “Lunar Logistics Drivers, Needs,” NASA said that as the Artemis missions and goals are conceptualized and planned, it is imperative to accurately predict logistics and resupply needs, not only for mission goals but for the very important need of keeping the humans alive and healthy. They need to have a good plan and the ability to transport landed cargo and exploration items from where they are delivered to where they are used. Graph showing approximate logistics item needs for representative lunar surface missions. Credit: NASA. “The total amount of logistics items required to keep the crew alive and healthy, to maintain systems, and to perform productive science and utilization can be relatively large,” the authors wrote. “It can also heavily influence the design of the architecture and exploration missions. The architecture must therefore be based on comprehensive, accurate estimates of logistics item needs and include assessment of a suitable logistics sub-architectures to deliver those needs.” How to provide various things like food, water, air, spare parts, and other similar products required to sustain life, as well as maintain all the various systems and structures are key to having productive science and utilization activities. NASA also expects they will need to move all these supplies around on the Moon, including to the lunar South Pole where they plan to send crews in the future. The paper outlines the importance of accurately predicting logistics resupply needs, as they can heavily influence the overall architecture and design of exploration missions. An artist’s conception shows NASA’s generic concept for the Lunar Terrain Vehicle. (NASA Illustration) NASA’ said their current planned lunar mobility elements, such as the Lunar Terrain Vehicle and Pressurized Rover, have a capability limit of about 1,760 pounds (800 kilograms) and will primarily be used to transport astronauts around the lunar surface. However, future missions could include a need to move cargo totaling around 4,400 to 13,000 pounds (2,000 to 6,000 kg). That’s why NASA wants input from companies who have experience in this area. But to be able to move cargo around to various places on the Moon, NASA first needs to get the supplies to the lunar surface. The second white paper, “Lunar Surface Cargo,” looks at the lunar surface cargo delivery needs, compares those needs with current cargo lander capabilities, and outlines considerations for fulfilling this capability gap. NASA said that access to a diverse fleet of cargo landers would empower a larger lunar exploration footprint, and that a combination of international partnerships and U.S. industry-provided landers could supply the concepts and capabilities to meet this need. “Given diverse cargo needs of varying size, mass, delivery cadence, and operational needs, a diverse portfolio of cargo lander capabilities will be necessary to achieve NASA’s Moon to Mars Objectives,” the paper says. “Encouraging the development of varied cargo lander concepts and capabilities will be key to establishing a long-term lunar presence for science and exploration.” Planned and potential cargo to the lunar surface. Credit: NASA While the request for proposals doesn’t explicitly seek new concepts for landing vehicles, it does ask for integrated assessments of logistics that can include transportation elements. “We’re looking for industry to offer creative insights that can inform our logistics and mobility strategy,” said Brooke Thornton, industry engagement lead for NASA’s Strategy and Architecture Office. “Ultimately, we’re hoping to grow our awareness of the unique capabilities that are or could become a part of the commercial lunar marketplace.” Got ideas? Check out NASA’s Request for Proposals. The post NASA Wants to Move Heavy Cargo on the Moon appeared first on Universe Today.

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