Landing a robotic probe on the surface of an icy moon can complicate the search for life. Therefore it is worth digging deeper.
The search for signs of life or its predecessors on the surface of the moon of Jupiter Europe may not be set at the very beginning. Therefore, many scientists suggest deepening.
The ocean, containing twice the amount of water than all the seas of the earth, is splashing under the 10-15-mile (15-25 km) ice crust. For this reason, astrobiologists believe that the moon is 1,900 miles (3,100 km) wide — one of the best contenders in the Solar System for extraterrestrial life.
In addition, the Hubble Space Telescope noticed the presence of plumes of water vapor flowing from the southern polar region. They suggest that this ocean material could fall back onto the ice surface.
This is a unique perspective for NASA, which is going to launch the device to Europe in the 2020s to detect chemical evidence of life support. NASA’s mission was limited to overflight, but the US Congress ordered the inclusion of a landing in the plan.
However, this complicates the task. Burning a low-thrust engine to slow the descent will “flood the soil with ammonia and this will greatly interfere with the work,” said Ralph Lorenz, a planetary scientist at the Johns Hopkins University of Maryland Applied Physics Laboratory.
This is inconvenient since there is nitrogen in ammonia. “Everything in our body contains nitrogen,” he says. “If you look for nitrogen in the atmosphere, then finding it in Europe will be a real bliss. But what to do with preliminary pollution, even if it is not very large? ”. If you use this method, then scientists will have to figure out whether the nitrogen was native to the planet, or whether we brought it there when landing.
In a study, Lorenz discovered that landing a 440-pound spacecraft on Europe would disrupt the state of the surface 30 feet (9 meters) around the landing module. He made this conclusion by analyzing images of previous impacts from landings on the earth Moon and Mars.
Scientists find it difficult to guess whether the device can move away from such a site. The Curiosity rover has wheels, so it drove off in 2012, but we have little information about the dangers of the surface of Europe.
“Hedges can lead to a tilting or it will just fall into the crevice,” said Lorenz. “We cannot rely on luck, otherwise we will throw out 1-2 billion dollars into emptiness.”
The problem of nitrogen pollution is much more complicated than on Mars or the Moon, because this satellite is colder. Its temperature does not rise above -260 degrees Fahrenheit (-160 centigrade). Under such conditions, ammonia is likely to be retained on the surface, which allows it to interact with other molecules and, possibly, create confusion in the observations.
Other researchers say surface samples are important, but more valuable specimens are hidden deeper. “We need to go below the surface,” said Britney Schmidt, a planetary scientist at the Institute of Technology.
Schmidt believes that you need to drill at least 4 inches (10 cm) to a place where there is no contaminated ice and cosmic radiation that destroys biogenic molecules. “If we drop 10 cm or a meter (3 feet), we’ll get an area that was not affected by the engine,” she says. “The deeper you dive, the more valuable the samples.”
The device does not just go look for ammonia or nitrogen. This emphasizes Peter Willis, a chemist at NASA's Jet Propulsion Laboratory in Pasadena, California.
The mission will take precautions to get directly into the ice. NASA plans to use the method of landing a celestial crane, which lowered Curiosity to Mars. Approaching the surface, the spacecraft will launch a thruster that allows it to hang in the air. At this time, he will lower the device to the surface with a cord.
In this case, “the device will fall, but we hope that the height will not be large,” - says Willis.
Restricting terrestrial organics will help NASA find extraterrestrial life, even if these organisms do not walk, but float.
“It’s too early to go fishing,” he says. “But there is hope of discovering the biogenic molecules necessary for life.”