Month: October 2019

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  Over three weeks in April and May of 2019, NASA's Lander Vision System flew 17 flights attached to the front of a helicopter. [credit: Pursuit Aviation ]

If all goes well, the Mars 2020 mission will launch toward the Red Planet next July. Then, after a six-month cruise to Mars, a lander carrying a 1-ton rover will detach from the spacecraft and attempt to make a soft landing in an ancient lake bed named Jezero Crater.

Most likely, it will all go well despite the enormous challenge of safely sending spacecraft to Mars. Historically, about 50% of missions have failed. But NASA has gotten pretty good at this stuff, and there's a reason for that. The agency works really hard at getting all of the details right.

Probably the most challenging part of the Mars 2020 mission involves putting the rover on the ground. It is true that NASA performed pretty much the same landing profile in August 2012 with the similarly sized Curiosity rover. However, there is one key difference—whereas Curiosity sought a safe landing site in the relatively smooth terrain of Gale Crater, the Mars 2020 mission will land in a more sporty location with boulders and other hazards.

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  The many, many parts of the Galaxy Fold.

The Samsung Galaxy Fold finally launched in the US on Friday after a five-month delay, and with retail units out in the wild, the phone has reappeared on iFixit's teardown bench.

iFixit previously tore down the Galaxy Fold back in April, before the phone was even technically released, having somehow acquired a recalled unit. iFixit really explored the device, providing details about why the phones were dying early and suggesting solutions for Samsung. Samsung did not take kindly to its design failures being laid bare before the Internet, and it went after iFixit's supplier, forcing the site to remove the teardown. The original teardown from April is still up on Archive.org, though, and can now be freely compared to this new Galaxy Fold teardown after five months of reworking back at Samsung HQ.

First, the Galaxy Fold has gained some weight. During the original launch in April, the device was specced at 263g, but now the device is 276g. A good bet for where that extra 13 grams of weight came from was in Samsung's description of the Fold redesign, which included "additional metal layers" under the display. iFixit writes that this is actually a flexible, "chainmail armor" that now lives immediately under the display.

Enlarge (credit: World Meterological Organization)

Huge numbers of people depend on water drawn from the ground, especially in drier regions, but these water resources are being steadily depleted. Less water in the ground doesn't just mean less water for us—it also means less water to flow into the rivers and streams that support freshwater ecosystems.

These dwindling supplies are set to have a devastating impact. A paper in Nature this week takes a close look at the use of groundwater around the world, estimating the point at which it becomes unsustainable. The news is dire: in many places, we're already there, and for many more, the limit will be hit within the next thirty years.

A delicate balance

Groundwater "is the world's largest freshwater resource," write hydrologist Inge de Graaf and her colleagues. It's used heavily in agriculture, which means it's important for food security, and it plays a particularly crucial role for people in arid areas or during droughts.