"Earth's ozone layer blocks the Sun's shortest wave radiation, called UV-C, which is so damaging to cells in high doses that it's a go-to sterilizer in hospitals," writes Slashdot reader sciencehabit. "UV-C is such a killer, in fact, that scientists have questioned whether life can survive on worlds that lack an ozone layer, such as Mars or distant exoplanets. "But research published this month in Astrobiology suggests one hardy lichen, a hybrid organism made of algae and fungi, may have cracked the UV-C code with a built-in sunscreen, despite never experiencing these rays in its long evolutionary history." Science magazine explains: When scientists brought a sample of the species, the common desert dweller Clavascidium lacinulatum, back to the lab, graduate student Tejinder Singh put the lichen through the wringer. First, Singh dehydrated the lichen, to make sure it couldn't grow back in real time and mask any UV damage. Then he placed the lichen a few centimeters under a UV lamp and blasted it with radiation. The lichen seemed just fine. So Singh purchased the most powerful UV-C lamp he could find online, capable of sending out 20 times more radiation than the amount expected on Mars. When he tested the lamp on the most radiation-resistant life form on Earth, the bacterium Deinococcus radiodurans, it died in less than a minute. After 3 months—likely the highest amount of UV-C radiation ever tested on an organism—Singh pulled the sample so he could finish his master's thesis in time. About half of the lichen's algal cells had survived. Then, when the team ground up and cultured part of the surviving lichen, about half of its algal cells sprouted new, green colonies after 2 weeks, showing it maintained the ability to reproduce. The species may provide a blueprint for surviving on Mars or exoplanets, which don't have an ozone layer to protect them.

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alternative_right shares a report from Phys.Org: Using conventional propulsion and low-energy trajectories, it takes six to nine months for crewed spacecraft to reach Mars. These durations complicate mission design and technology requirements and raise health and safety concerns since crews will be exposed to extended periods in microgravity and heightened exposure to cosmic radiation. Traditionally, mission designers have recommended nuclear-electric or nuclear-thermal propulsion (NEP/NTP), which could shorten trips to just 3 months. In a recent study, a UCSB physics researcher identified two trajectories that could reduce transits to Mars using the Starship to between 90 and 104 days. The study was authored by Jack Kingdon, a graduate student researcher in the Physics Department at the University of California, Santa Barbara (UCSB). He is also a member of the UCSB Weld Lab, an experimental ultracold atomic physics group that uses quantum degenerate gases to explore quantum mechanical phenomena. [...] As outlined on its website, conference presentations, and user manual, the SpaceX mission architecture consists of six Starships traveling to Mars. Four of these spacecraft will haul 400 metric tons (440 U.S. tons) of cargo while two will transport 200 passengers. Based on the Block 2 design, which has a 1,500 metric ton (1,650 U.S. ton) propellant capacity, the crewed Starships will require 15 tankers to fully refuel in low Earth orbit (LEO). The cargo ships would require only four, since they would be sent on longer low-energy trajectories. Once the flotilla arrives at Mars, the Starships will refuel using propellant created in situ using local carbon dioxide and water ice. When the return window approaches, one of the crew ships and 3-4 cargo ships will refuel and then launch into a low Mars orbit (LMO). The cargo ships will then transfer the majority of their propellant to the crew ship and return to the surface of Mars. The crew ship would then depart for Earth, and the process could be repeated for the other crew ship. Kingdon calculated multiple trajectories using a Lambert Solver, which produces the shortest elliptical arc in two-body problem equations (aka Lambert's problem). The first would depart Earth on April 30th, 2033, taking advantage of the 26-month periodic alignment between Earth and Mars. The transit would last 90 days, with the crew returning to Earth after another 90-day transit by July 2nd, 2035. The second would depart Earth on July 15th, 2035, and return to Earth after a 104-day transit on December 5th, 2037. As Kingdon explained, the former trajectory is the most likely to succeed: "The optimal trajectory is the 2033 trajectory -- it has the lowest fuel requirements for the fastest transit time. A note that may not be obvious to the layreader is that Starship can very easily reach Mars in ~3 months -- in fact, it can in any launch window, over a fairly wide range of trajectories. However, Starship may impact the Martian atmosphere too fast (although we do not know, and likely SpaceX don't either actually how fast Starship can hit the Martian atmosphere and survive). The trajectories discussed are ones that I am confident Starship will survive." The paper describing the work has been published in the journal Scientific Reports.

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President Trump's 2026 budget proposes over $1 billion for Mars exploration through a new Commercial Mars Payload Services Program, while simultaneously slashing NASA's overall budget by 25%. Phys.Org reports: Under the proposal, NASA would award contracts to companies developing spacesuits, communications systems and a human-rated landing vehicle to foster exploration of the Red Planet. Trump's proposed $18.8 billion NASA budget would cut the agency's funding by about 25% from the year before, with big hits to its science portfolio. The fleshed-out request on Friday builds upon a condensed budget proposal released earlier this month. "We must continue to be responsible stewards of taxpayer dollars," NASA Acting Administrator Janet Petro wrote in a letter included in the request. "That means making strategic decisions -- including scaling back or discontinuing ineffective efforts." The new Mars scheme is modeled after NASA's Commercial Lunar Payload Services program that has benefited Intuitive Machines LLC, Firefly Aerospace Inc. and Astrobotic Technology Inc., though it has achieved mixed results. According to the budget, the contract to land on Mars would build upon existing lander contracts. America's Next NASA Administrator Will Not Be Former SpaceX Astronaut Jared Isaacman

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For the first time, scientists have directly observed atmospheric sputtering in action on Mars -- an erosion process driven by solar wind ions that may have played a major role in the planet's atmospheric and water loss. ScienceAlert reports: The only spacecraft with the equipment and orbital configuration to make these observations is NASA's MAVEN. The researchers carefully pored over the data collected by the spacecraft since it arrived in Mars orbit in September 2014, looking to find simultaneous observations of the solar electric field and an upper atmosphere abundance of argon -- one of the sputtered particles, used as a tracer for the phenomenon. They found that, above an altitude of 350 kilometers (217 miles), argon densities vary depending on the orientation of the solar wind electric field, compared to argon densities at lower altitudes that remain consistent. The results showed that lighter isotopes of argon vary, leaving behind an excess of heavy argon -- a discrepancy that is best explained by active sputtering. This is supported by observations of a solar storm, the outflows of which arrived at Mars in January 2016. During this time, the evidence of sputtering became significantly more pronounced. Not only does this support the team's finding that argon density variations at high Martian altitudes are the result of sputtering, it demonstrates what conditions may have been like billions of years ago, when the Sun was younger and rowdier, undergoing more frequent storm activity. The findings have been published in the journal Science Advances.

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Evidence is mounting for "a vast reservoir of liquid water" on Mars, according to a new article by Australian National University professor Hrvoje TkalÄiÄ and geophysics associate professor Weijia Sun from the Chinese Academy of Geological Sciences, announcing their recently published paper. "Using seismic data from NASA's InSight mission, we uncovered evidence that the seismic waves slow down in a layer between 5.4 and 8 kilometres below the surface, which could be because of the presence of liquid water at these depths." Mars is covered in traces of ancient bodies of water. But the puzzle of exactly where it all went when the planet turned cold and dry has long intrigued scientists... Billions of years ago, during the Noachian and Hesperian periods (4.1 billion to 3 billion years ago), rivers carved valleys and lakes shimmered. As Mars' magnetic field faded and its atmosphere thinned, most surface water vanished. Some escaped to space, some froze in polar caps, and some was trapped in minerals, where it remains today. But evaporation, freezing and rocks can't quite account for all the water that must have covered Mars in the distant past. Calculations suggest the "missing" water is enough to cover the planet in an ocean at least 700 metres deep, and perhaps up to 900 metres deep. One hypothesis has been that the missing water seeped into the crust. Mars was heavily bombarded by meteorites during the Noachian period, which may have formed fractures that channelled water underground. Deep beneath the surface, warmer temperatures would keep the water in a liquid state — unlike the frozen layers nearer the surface. In 2018, NASA's InSight lander touched down on Mars to listen to the planet's interior with a super-sensitive seismometer. By studying a particular kind of vibration called "shear waves", we found a significant underground anomaly: a layer between 5.4 and 8 kilometres down where these vibrations move more slowly. This "low-velocity layer" is most likely highly porous rock filled with liquid water, like a saturated sponge. Something like Earth's aquifers, where groundwater seeps into rock pores. We calculated the "aquifer layer" on Mars could hold enough water to cover the planet in a global ocean 520-780m deep. InSight's seismometer captured vibrations between the crust of Mars and its lower layers from two meteorite impacts in 2021 and a Marsquake in 2022. "These signatures let us pinpoint boundaries where rock changes, revealing the water-soaked layer 5.4 to 8 kilometres deep." It's an exciting possibility. "Purified, it could provide drinking water, oxygen, or fuel for rockets." And since microbes thrives on earth in deep rocks filled with water, "Could similar life, perhaps relics of ancient Martian ecosystems, persist in these reservoirs?"

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