New Delhi: NASA in the past week announced the crew that will fly aboard its Artemis II mission — a lunar mission that will pave the way for further deep space explorations.
Christina Koch, the first woman astronaut ever assigned to a lunar mission, and Victor Glover, who will be the first black astronaut to fly to the Moon, are part of the mission that takes humanity back to the Earth’s satellite, after a gap of 50 years. Reid Wiseman and Jeremy Hansen are the other two members.
The crew will lift off on the approximately 10-day mission from NASA’s Kennedy Space Center in Florida, aboard the foundational deep space rocket, the Space Launch System, and Orion spacecraft.
The mission will confirm all the spacecraft’s systems operate as designed with crew aboard in the actual environment of deep space. Over the course of about two days, the astronauts will check out Orion’s systems and perform a targeting demonstration test relatively close to the Earth before then beginning the trek toward the Moon.
Orion’s European-built service module will give the spacecraft the big push needed to break free from the Earth orbit and set course for the Moon. This trans-lunar injection burn will send the astronauts on an outbound trip of about four days, taking them around the far side of the Moon, where they will ultimately create a figure eight extending more than 230,000 miles from the Earth. At their maximum distance, the crew will fly about 6,400 miles beyond the Moon. During the approximate four-day return trip, the astronauts will continue to evaluate the spacecraft’s systems.
Instead of requiring propulsion on the return, this fuel-efficient trajectory harnesses the Earth-Moon gravity field, ensuring that — after its trip around the far side of the Moon — Orion will be pulled back naturally by the Earth’s gravity for the free return portion of the mission.
The crew will endure the high-speed, high-temperature reentry through the Earth’s atmosphere before splashing down in the Pacific Ocean off the coast of San Diego, where a recovery team of NASA and Department of Defense personnel will bring them back to shore. Read more
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Zircons may have preserved signatures of life from early Earth
Scientists from Germany’s Heidelberg University have succeeded in tracing a very old and rare remnant of earlier life on the Earth, trapped in the crystals of the mineral zircon.
Zircon crystals, like a time capsule, can preserve traces of life hundreds of millions of years old in the form of biogenic carbon.
According to the research team, their work opens up new possibilities for research into our planet’s early period for which neither fossils nor sediments have been preserved in original form.
Zircon mineral grains form from magma, i.e., melted rock, in an extremely hot and intrinsically hostile environment. Yet heated remnants of organisms were converted to carbon dioxide and methane and deposited as graphite in the mineral zircon at approximately 700°C.
The special isotopic signature of biogenic carbon remains largely preserved in most inclusions and leaves behind a kind of fingerprint of earlier life forms, according to the researchers.
Taking the measurements is extremely demanding, emphasise the researchers. First, intact graphite inclusions, some measuring just a few micrometers and thus a hundred times finer than a human hair, must be found and identified within zircon crystals.
To exclude contamination with carbon from the environment, non-destructive Raman microspectroscopy is used to examine the encapsulated inclusions in place in zircons.
Zircons are among the oldest minerals on the Earth, some older than four billion years. For the first hundred million years, these crystals represent the only known record holding information on very early conditions on the planet. Inclusions in these oldest zircons have already revealed that water and oceans existed on the Earth early on, as well as movements of the continental plates. Read more.
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Himalaya losing glaciers much faster than thought
The Himalayas may be losing its glaciers at a much faster pace than thought. Researchers now estimate a loss of meltwater equivalent in weight to 570 million elephants, or more than 1,000 times the total number of elephants living in the world.
Scientists from Scotland’s University of St Andrews found that the mass loss of lake-terminating glaciers in the Greater Himalayas has been significantly underestimated due to the inability of satellites to see glacier changes occurring underwater.
Published in Nature Geoscience, the new study by researchers including those from the Chinese Academy of Sciences, Graz University of Technology in Austria, and Carnegie Mellon University in the US, demonstrates that a previous assessment underestimated the total mass loss of lake-terminating glaciers in the Greater Himalayas by 6.5 per cent.
The most significant underestimation of 10 per cent occurred in the Central Himalayas, where glacial lake growth has been the most rapid. A particularly interesting case is Galong Co, a lake, in this region, with a high underestimation of 65 per cent.
This oversight was largely due to the limitations of satellite imaging in detecting underwater changes, which has led to a knowledge gap in our understanding of the full extent of glacier loss.
From 2000 to 2020, proglacial lakes in the region increased by 47 per cent in number, 33 per cent in area, and 42 per cent in volume. This expansion resulted in an estimated glacier mass loss of around 2.7 Gross tonnage (Gt), equivalent to the weight of 570 million elephants.
This loss was not considered by previous studies as the utilized satellite data can only measure the lake water surface, but not the ice underwater replaced by water.
The study also highlights the need to understand the mechanisms driving glacier mass loss and the underestimated mass loss of lake-terminating glaciers globally, which is estimated to be around 211.5 Gt, or roughly 12 per cent, between 2000 and 2020. Read more.
New method to print recyclable electronics ditches toxic chemicals
Scientists at the US’ Duke University have produced the world’s first fully recyclable printed electronics that replace the use of chemicals with water in the fabrication process. By bypassing the need for hazardous chemicals, the technology could pave the way to reduce the environmental footprint and human health risks.
One of the dominant challenges facing electronics manufacturers is successfully securing several layers of components on top of each other, which is crucial to making complex devices. Getting these layers to stick together can be a frustrating process, particularly for printed electronics.
In previous work, Aaron D. Franklin and his group demonstrated the first fully recyclable printed electronics. The devices used three carbon-based inks: semiconducting carbon nanotubes, conductive graphene and insulating nanocellulose. In trying to adapt the original process to only use water, the carbon nanotubes presented the largest challenge.
To make a water-based ink in which the carbon nanotubes don’t clump together and spread evenly on a surface, a surfactant similar to detergent is added. The resulting ink, however, does not create a layer of carbon nanotubes dense enough for a high current of electrons to travel across.
The team has now developed a cyclical process in which the device is rinsed with water, dried in relatively low heat and printed on again. When the amount of surfactant used in the ink is also tuned down, the researchers show that their inks and processes can create fully functional, fully recyclable, fully water-based transistors.
Compared to a resistor or capacitor, a transistor is a relatively complex computer component used in devices such as power control or logic circuits and sensors. Read more.
(Edited by Tony Rai)
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