The stunning $2.5 billion mission to land on ‘the most exciting object in the solar system’

Saturn’s sixth-largest moon Enceladus is the most exciting object in the solar system, according to some. It has a warm, salty ocean 12 miles/20 kilometers below its icy surface that appears potentially habitable.

Could Enceladus have some kind of extraterrestrial aquatic life that evolved entirely separately from life on Earth?

It is a matter of utmost importance in the planetary science and astrobiology communities. So much so that pressure is mounting for NASA to send a flagship mission to Enceladus to find out exactly what’s going on beneath the tiny moon’s icy crust.

It’s a matter currently under investigation as part of the Decadal Survey for Planetary Science and Astrobiology, a National Academy of Sciences report that will set NASA’s priorities for the next 10 years. It will be released on April 19, 2022.

Will the incredible mission “Orbilander” be on this list?

Orbilander, a concept for a NASA flagship mission costing about $3 billion, would see a single spacecraft first orbit and then land on Enceladus.

“Enceladus hosts the best characterized ocean in the solar system, second only to Earth’s,” said Shannon M. MacKenzie, planetary scientist in the Laboratory of Applied Physics at Johns Hopkins University and author of the Enceladus Orbilander Mission Concept. Enceladus has a heat source and liquid water, and we know these two things combine to create a fantastically fascinating variety of life on our planet. So why not on Enceladus? “There’s liquid water there and the chemical ingredients that we think biochemistry needs, but it’s very difficult to use the typical tools that a satellite would need to have to interrogate that ocean because it’s miles under ice.” lies,” said MacKenzie.

Oh yes, the ice cream.

Scientists have known Enceladus has a 30-kilometer-deep subterranean ocean since 2014, when data from NASA’s Cassini spacecraft showed the tiny moon has Yellowstone-style geysers erupting through cracks in the ice. “At the South Pole, you have these long rifts, 10 kilometers long, that have these individual jets that spew material out of the ocean into space,” MacKenzie said.

Scientists call them “tiger stripes” and they look like this:

These geysers theoretically allow a spacecraft to probe its subsurface ocean without actually having to walk through its icy crust.

“Cassini’s incredible images of Enceladus helped peel off the layers of what’s going on,” MacKenzie said. “We are now able to make really compelling arguments that Enceladus is a potentially habitable environment.”

This ocean is probably heated by the moon’s core; Keyword theories about hydrothermal vents – like those found on Earth – that could support life.

A recent study suggests that the subsurface ocean on Enceladus appears to be traversed by currents like those in Earth’s oceans. Another that it hosts ice quakes. There is also intriguing evidence of water-rock interactions at the bottom of the ocean.

“If I had to put my money on something in the solar system that would be a blast to get the information we need and say that life exists, it would be Enceladus,” said Dr. Jackie Faherty, Senior Scientist and Senior Education Manager jointly manages the Department of Astrophysics and the Department of Education at the American Museum of Natural History. “You don’t have to dig a hole—these geysers shoot up this material for a spacecraft to stick out its tongue to lick…Enceladus is the most exciting object in the solar system.”

But Orbilanders want land on Enceladus. “Orbilander will examine these plumes — actually ice particles in space that came out of these cracks — about twice a day for 200 days and then land,” MacKenzie said. “That’s because the biggest particles won’t make it up – they don’t have enough kinetic energy – so they fall back to the surface.”

In fact, landing on Enceladus will be easier than, say, on Mars because, being a much smaller body, there’s a lot less gravity – about a hundredth of Earth’s gravity.

The main problem with the Orbilander mission concept is that Enceladus is so tiny. It’s only 500 kilometers across – about one-seventh the size of our moon – so getting out of Saturn’s orbit and into orbit around Enceladus won’t be easy. “One option is to carry a lot of fuel, but that’s expensive,” MacKenzie said. In dollars, yes, but also in terms of mass – the bigger the spacecraft, the slower it will travel. “Another option is to take advantage of gravity assist and do a ‘lunar tour’ in the Saturn system,” MacKenzie said.

Any mission to Enceladus will not happen tomorrow, whatever the Decadal Survey recommends, which NASA is working on. The Orbilander concept calls for a 2038 launch and 2050 arrival to begin a 200-day orbit. After sampling the swaths for “life detection”, a suitable landing site can be found.

Is 2050 too far away to get excited about Enceladus? Maybe, but there are good reasons to wait until then. “Then the south pole of Enceladus will come into the southern summer, which means more of it will be illuminated as the mission progresses,” MacKenzie said.

Although it was Cassini who revealed its subsurface ocean, NASA’s Voyager images in the 1980s showed that Enceladus was both very bright and crater-free; Evidence that it was covered with highly reflective ice and that its surface is constantly being renewed. In short, Enceladus is geologically active – it’s warm and it’s wet… this is where life as we know it can exist.

Enceladus will always be a world of interest when searching for life beyond Earth. It is certainly only a matter of time now before NASA visits them.

I wish you clear skies and big eyes.

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