[CENTRAAL] MARS - De Missies! Deel 10

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News | June 24, 2016
NASA Weighs Use of Rover to Image Potential Mars Water Sites



Ever since it was announced that there may be evidence of liquid water on present-day Mars, NASA scientists have wondered how best to further investigate these long, seasonally changing dark streaks in the hope of finding evidence of life -- past or present -- on the Red Planet.

"It's not as simple as driving a rover to a potential site and taking a scoop of soil," said Jim Green, NASA's director of planetary science. "Not only are these on steep slopes, we need to ensure that planetary protection concerns are met. In other words, how can we search for evidence of life without contaminating the sites with bugs from Earth?"

Pending approval of a mission extension, NASA's Curiosity Mars rover will continue to climb to progressively higher and younger strata on Mount Sharp, investigating how long the ancient, water-rich environments found so far persisted as Mars dried out. Reaching those destinations would bring the rover closer to locations where dark streaks are present on some slopes. On the way, the route would allow the one-ton rover to capture images of the potential water sites from miles away and see if any are the seasonally changing type.

The features of interest have been observed by NASA's High-Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter (MRO). They appear as dark lines that appear to ebb and flow over time. Planetary scientists think these gullies or recurring slope lineae (RSLs) may appear seasonally as a form of briny water at or near the surface of the Red Planet under warmer conditions.

There are two RSL candidates that may be within Curiosity's reach, on the side of the 3.1-mile-high (5-kilometer-high) Mount Sharp. The rover's Remote Micro-Imager (part of ChemCam) would be the main instrument for imaging the possible sites. The goal would be to study the regions over time to see if there are any changes and to rule out other causes for the changes, such as dry avalanches.

How close could the rover safely get to an RSL? "That's exactly the question that needs to be addressed early in the process," said Catharine Conley, NASA's planetary protection officer. "Kilometers away -- it's unlikely that it would be an issue. In terms of coming much closer, we need to understand well in advance the potential for Earth organisms to come off the rover, and that will tell us how far away the rover should stay."

Conley notes that while the Martian environment is considered harsh for many organisms, that's not necessarily the case for all of them -- particularly microbes that might be hiding within the nooks and crannies of a robotic explorer.

The darkish streaks are considered "special regions" on Mars, where extra precautions must be taken to prevent contamination because of the suspected presence of liquid water, considered a prerequisite for life.

The Mars Science Laboratory (MSL) spacecraft launched from Cape Canaveral, Florida, on Nov. 26, 2011, arriving on the Red Planet on Aug. 6. 2012. NASA's most ambitious Mars mission to date, its goal was to study the Martian environment and determine if Mars is, or was, suitable for life. A decision on the rover's potential extended mission is expected in the next several months.

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MarsCuriosity twitterde op zaterdag 25-06-2016 om 01:07:46 Possible liquid water sites on Mars? I might get to investigate two on the surface from afar https://t.co/p7HA7Pzl7V https://t.co/P4ZV1pqFGs reageer retweet

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Mars Used To Have Earth-Like Levels Of Atmospheric Oxygen

Mars may be a famously red, dusty, thinly insulated planet now, but once upon a time, billions of years ago, it almost certainly had huge seas of liquid water and a warmer climate, not unlike our own world. Now, thanks to another glorious find from the Curiosity rover, researchers can confirm that Mars was even more Earth-like than anyone had ever realized.

Using its ChemCam instrument, which probes the geochemistry of any rock samples it comes across, Curiosity has determined that there are extremely high levels of manganese oxide present in surface-level Martian rocks – at least within the Gale crater in which the little mechanical laboratory is based. In order to get such high quantities of this compound, a planet requires just one thing: plenty of free oxygen floating around the atmosphere.

This means that, when these rocks formed, Mars had an atmosphere somewhat like that of Earth’s. Although it’s difficult to determine precisely how much free oxygen there was from this preliminary data, we now know that it must have been somewhat similar conditions to those that existed between 2 and 2.5 billion years ago, when something called the Great Oxygenation Event (GOE) occurred.

The GOE was most likely caused by the appearance of photosynthesizing life, which slowly converted the carbon dioxide-rich atmosphere on Earth into oxygen. When the surface geology could not chemically react with and subsequently absorb any more free oxygen, the rest was left to build up in the atmosphere, and the world was oxygenated.

Manganese oxide simply cannot form without extremely high quantities of free oxygen in the atmosphere, as observed on our own world at the time of the GOE. This also means that there was abundant liquid water on the surface, which agrees with multiple previous studies.

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Op zaterdag 25 juni 2016 09:43 schreef Resistor het volgende:
http://www.jpl.nasa.gov/news/news.php?feature=6542

[..]

Normaal kom ik hier niet, maar ik zag toevallig

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MarsCuriosity twitterde op zaterdag 25-06-2016 om 01:07:46 Possible liquid water sites on Mars? I might get to investigate two on the surface from afar https://t.co/p7HA7Pzl7V https://t.co/P4ZV1pqFGs reageer retweet

en dacht dat dit wel interessant was.

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Op dinsdag 28 juni 2016 22:54 schreef Molurus het volgende:
Wow.. dit is best indrukwekkend als het klopt:

http://www.iflscience.com(...)-atmospheric-oxygen/

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Klinkt als een sterke indicatie dat er leven op Mars heeft bestaan.

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Op woensdag 29 juni 2016 23:23 schreef Kijkertje het volgende:

Final ground test of NASA's Space Launch System

NASA just tested the rocket booster that'll take us to Mars

Last trial before launch.

NASA just passed a huge milestone in its mission to Mars, after conducting the final ground test of one of the boosters that'll power the Space Launch System (SLS) to the Red Planet.

It's the last trial of the system's boosters before the 2018 unmanned launch of the Orion spacecraft, and, as you can see from the footage below, everything looked really good lighting up the middle of the desert.

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The discovery of manganese oxides in Martian rocks might tell us that the Red Planet was once more Earth-like than previously believed. A new paper in Geophysical Research Letters reveals that NASA's Curiosity rover observed high levels of manganese oxides in Martian rocks, which could indicate that higher levels of atmospheric oxygen once existed on our neighboring planet.

This hint of more oxygen in Mars' early atmosphere adds to other Curiosity findings - such as evidence of ancient lakes - revealing how Earth-like our neighboring planet once was.

"The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes," said Nina Lanza, a planetary scientist at Los Alamos National Laboratory and lead author on the study published in the American Geophysical Union's journal. "Now we're seeing manganese-oxides on Mars and wondering how the heck these could have formed."

Lanza uses the Los Alamos-developed ChemCam instrument that sits atop Curiosity to "zap" rocks on Mars and analyze their chemical make-up. This work stems from Los Alamos National Laboratory's experience building and operating more than 500 spacecraft instruments for national defense, giving the Laboratory the expertise needed to develop discovery-driven instruments like ChemCam. In less than four years since landing on Mars, ChemCam has analyzed roughly 1,500 rock and soil samples.

Microbes seem a far-fetched explanation for the manganese oxides at this point, said Lanza, but the idea that the Martian atmosphere contained more oxygen in the past than it does now seems possible.

"These high-manganese materials can't form without lots of liquid water and strongly oxidizing conditions," said Lanza "Here on Earth, we had lots of water but no widespread deposits of manganese oxides until after the oxygen levels in our atmosphere rose due to photosynthesizing microbes."

In the Earth's geological record, the appearance of high concentrations of manganese is an important marker of a major shift in our atmosphere's composition, from relatively low oxygen abundances to the oxygen-rich atmosphere we see today. The presence of the same types of materials on Mars suggests that something similar happened there. If that's the case, how was that oxygen-rich environment formed?

"One potential way that oxygen could have gotten into the Martian atmosphere is from the breakdown of water when Mars was losing its magnetic field," said Lanza.

"It's thought that at this time in Mars' history, water was much more abundant." Yet without a protective magnetic field to shield the surface from ionizing radiation, that radiation started splitting water molecules into hydrogen and oxygen. Because of Mars' relatively low gravity, it wasn't able to hold onto the very light hydrogen atoms, but the heavier oxygen atoms remained behind.

"Much of this oxygen went into the rocks, leading to the rusty red dust that covers the surface today. While Mars' famous red iron oxides require only a mildly oxidizing environment to form, manganese oxides require a strongly oxidizing environment. These results suggest that past conditions were far more oxidizing (oxygen-rich) than previously thought.

"It's hard to confirm whether this scenario for Martian atmospheric oxygen actually occurred," Lanza added. "But it's important to note that this idea represents a departure in our understanding for how planetary atmospheres might become oxygenated." So far, abundant atmospheric oxygen has been treated as a so-called biosignature, or a sign of existing life.

The next step in this work is for scientists to better understand the signatures of non-biogenic versus biogenic manganese, which is directly produced by microbes. If it's possible to distinguish between manganese oxides produced by life and those produced in a non-biological setting, that knowledge can be directly applied to Martian manganese observations to better understand their origin.

The high-manganese materials were found in mineral-filled cracks in sandstones in the Kimberley region of Gale crater, which the Curiosity rover has been exploring for the last four years. But that's not the only place on Mars that abundant manganese has been found.

The Opportunity rover, which has been exploring Mars since 2004, also recently discovered high-manganese deposits in its landing site thousands of miles from Curiosity, which supports the idea that the conditions needed to form these materials were present well beyond Gale crater.

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Op woensdag 12 oktober 2016 10:36 schreef k3vil het volgende:
Ik snap niet dat de maan een goede optie is.
Helium 3, dichtbij de aarde, maanzand is makkelijk te gebruiken voor het maken van beton..

Mars heeft dit allemaal niet. Vooral de afstand is ruk.

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Op woensdag 12 oktober 2016 10:36 schreef k3vil het volgende:
Ik snap niet dat de maan een goede optie is.
Helium 3, dichtbij de aarde, maanzand is makkelijk te gebruiken voor het maken van beton..

Mars heeft dit allemaal niet. Vooral de afstand is ruk.