Jupiter's frozen moon Europa has a massive ocean below the surface that could potentially harbor life. To find out, NASA is in the early stages of building a robotic lander to explore the moon in the mid-2020s. Now though, Cardiff University researcher Daniel Hobley and colleagues suggest that touching down on Europa could be tricky due to fields of massive ice spikes jutting up as high as 50 feet. From Science
Such spikes are created on Earth in the frigid tropical peaks of the Andes Mountains, where they are called “penitentes,” for their resemblance to devout white-clad monks. First described by Charles Darwin, penitentes are sculpted by the sun in frozen regions that experience no melt; instead, the fixed patterns of light cause the ice to directly vaporize, amplifying minute surface variations that result in small hills and shadowed hollows. These dark hollows absorb more sunlight than the bright peaks around them, vaporizing down further in a feedback loop.
From the research paper in the scientific journal Nature:
We estimate that penitentes on Europa could reach 15 m in depth with a spacing of 7.5 m near the equator, on average, if they were to have developed across the interval permitted by Europa’s mean surface age. Although available images of Europa have insufficient resolution to detect surface roughness at the multi-metre scale, radar and thermal data are consistent with our interpretation. We suggest that penitentes could pose a hazard to a future lander on Europa.
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Astronomers working with the NASA Hubble Space Telescope have captured images of what might be water vapor plumes erupting from the surface of Jupiter's moon Europa. “This finding bolsters other Hubble observations suggesting the icy moon erupts with high altitude water vapor plumes,” reports NASA. “ The observation increases the possibility that missions to Europa may be able to sample Europa’s ocean without having to drill through miles of ice.”
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In the late 2020s, NASA plans to send a probe to Jupiter's moon Europa to determine if there's oceanic life beneath its crust. Before then, Draper Laboratory hopes that its novel sensor system of CubeSats, satellites smaller than a shoebox, and postage-stamp size sensors, called ChipSats, could be the basis of a complementary $10 million mission to inform the big 2020 effort, expected to cost $2 billion. Draper's idea is that CubeSats could be delivered to Europa's orbit to identify areas on the moon with the thinnest ice. As data comes in about what's below, the CubeSats would then dump hundreds of the tiny ChipSats onto the moon's surface. Those ChipSats would then identify the best location for the later NASA probe to penetrate the surface. (Insert requisite "2010: Odyssey Two" reference here.) From Draper Laboratory, developers of the system:
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Initial indications suggest that (ChipSats') small size and lack of moving parts may make them highly capable of surviving impact on a planetary surface without any dedicated protection system, (Draper researcher Brett) Streetman said. The low cost of ChipSats would enable scientists to use a large batch, reducing the consequences of losing some upon impact, he said.
Additionally, this capability could provide a quick-response solution for researchers who study events on Earth that are difficult to predict, and thus difficult to reach quickly with personnel and in-situ sensors, such as volcanic eruptions and algae blooms, said John West, who leads advanced concepts and technology development in Draper’s space systems group.
Researchers at the Universidad de Buenos Aires recreated conditions found on the surface of Jupiter's moon Europa in the lab, and then proved that some Earth organisms are capable of surviving in that extreme environment. At least, for three hours. It's one experiment in a growing body of work aimed at proving that Earth could seed other planets with life. Read the rest