Saturn’s Moon Enceladus Shows More Signs It Could Support Alien Life

Saturn’s icy moon Enceladus is looking more and more like a habitable world.

The same sorts of chemical reactions that sustain life near deep-sea hydrothermal vents here on Earth could potentially be occurring within Enceladus’ subsurface ocean, a new study published today (April 13) in the journal Science suggests.

These reactions depend on the presence of molecular hydrogen (H2), which, the new study reports, is likely being produced continuously by reactions between hot water and rock deep down in Enceladus’ sea.

Related: Photos of Enceladus, Saturn’s Geyser-Blasting Moon

“The abundance of H2, along with previously observed carbonate species, suggests a state of chemical disequilibria in the Enceladus ocean that represents a chemical energy source capable of supporting life,” Jeffrey Seewald, of the Marine Chemistry and Geochemistry Department at the Woods Hole Oceanographic Institution in Massachusetts, wrote in an accompanying “Perspectives” piece in the same issue of Science. (Seewald was not involved in the new Enceladus study.)

A Geyser-Blasting Ocean World

The 313-mile-wide (504 kilometers) Enceladus is just Saturn’s sixth-largest moon, but the object has loomed large in the minds of astrobiologists since 2005.

In that year, NASA’s Saturn-orbiting Cassini spacecraft first spotted geysers of water ice erupting from “tiger stripe” fissures near Enceladus’ south pole. Scientists think these geysers are blasting material from a sizeable ocean buried beneath the satellite’s ice shell.

So, Enceladus has liquid water, one of the key ingredients required for life as we know it. (This ocean stays liquid because Saturn’s immense gravitational pull twists and stretches the moon, generating internal “tidal” heat.) And the new study suggests that the satellite possesses another key ingredient as well: an energy source.

 

A team of researchers led by Hunter Waite, of the Southwest Research Institute (SwRI) in San Antonio, analyzed observations made by Cassini during an October 2015 dive through Enceladus’ geyser plume.

This plunge was special in several ways. For one thing, it was Cassini’s deepest-ever dive through the plume; the probe got within a mere 30 miles (49 km) of Enceladus’ surface. In addition, Cassini’s Ion and Neutral Mass Spectrometer (INMS) instrument alternated between “open-source” and “closed-source” modes during the encounter, rather than sticking to closed source (the usual routine).

INMS is just 0.25 percent as sensitive in open-source mode as it is in closed-source mode, Waite and his colleagues wrote in the new Science paper. But open source has a key advantage: It minimizes artifacts that have complicated previous attempts to measure H2 levels in the plume.

With this analytical hurdle cleared, Waite and his team were able to calculate that H2 makes up between 0.4 percent and 1.4 percent of the volume of Enceladus’ geyser plume. Further calculations revealed that carbon dioxide (CO2) makes up an additional 0.3 percent to 0.8 percent of the plume’s volume.

Related: Inside Enceladus, Icy Moon of Saturn (Infographic)

The molecular hydrogen is most likely being produced continuously by reactions between hot water and rock in and around Enceladus’ core, Waite and his colleagues concluded. They considered other possible explanations and found them wanting. For example, neither Enceladus’ ocean nor its ice shell are viable long-term reservoirs for volatile H2, the authors wrote, and processes that disassociate H2 from water ice in the shell don’t seem capable of generating the volume measured in the plume.

The hydrothermal explanation is also consistent with a 2016 study by another research group, which concluded that tiny silica grains detected by Cassini could have been produced only in hot water at significant depths.

“The story seems to be fitting together,” Chris Glein of SwRI, a co-author of the new Science paper, told Space.com.

Deep-Sea Chemical Reactions

Earth’s deep-sea hydrothermal vents support rich communities of life, ecosystems powered by chemical energy rather than sunlight.

“Some of the most primitive metabolic pathways utilized by microbes in these environments involve the reduction of carbon dioxide (CO2) with H2 to form methane (CH4) by a process known as methanogenesis,” Seewald wrote.

The inferred presence of H2 and CO2 in Enceladus’ ocean therefore suggests that similar reactions could well be occurring deep beneath the moon’s icy shell. Indeed, the observed H2 levels indicate that a lot of chemical energy is potentially available in the ocean, Glein said.

“It’s quite a bit larger than the minimum energy required to support methanogenesis,” he said.

Glein stressed, however, that nobody knows whether such reactions are actually occurring on Enceladus.

“This is not a detection of life,” Glein said. “It increases the habitability, but I would never suggest that this makes Enceladus more or less likely to have life itself. I think the only way to answer that question is, we need data.”

Seewald also counseled caution on astrobiological interpretations. He noted, for example, that molecular hydrogen is rare in Earth’s seawater, because hungry microbes quickly gobble it up.

“Is the presence of H2 in the Enceladus ocean an indicator for the absence of life, or is it a reflection of the very different geochemical environment and associated ecosystems on Enceladus?” Seewald wrote. “We still have a long way to go in our understanding of processes regulating the exchange of mass and heat across geological interfaces that define the internal structure of Enceladus and other ice-covered planetary bodies.”

Originally published on Space.com.

Blue Origin makes historic reusable rocket landing in epic test flight

Go AMAZON Go !

The private spaceflight company Blue Origin just launched itself into the history books by successfully flying and landing a reusable rocket.

Powered by the company’s own BE-3 engine, the rocket kicked off the launchpad on Nov. 23 at 11:21 a.m. Central Time, carrying the New Shepard space vehicle. The stunning feat was captured in an amazing test flight video released by the company.

Shortly after liftoff, the rocket separated from the vehicle. In the past, a spent rocket would fall back to Earth like a stone, having completed its one and only flight.

But Blue Origin’s rocket didn’t fall aimlessly back to Earth; instead, it was guided toward a landing pad, where it re-ignited its engines, hovered briefly above the ground and finally touched down softly on the pad, remaining upright and intact. This soft landing means the rocket can be used for more flights, which Blue Origin and other companies have said will significantly drive down the cost of spaceflight. [See more photos of Blue Origin’s epic test flight]

No other agency or company has successfully landed a reusable rocket before.

“Rockets have always been expendable. Not anymore,” stated a blog post on the company’s website, written by founder Jeff Bezos, the billionaire who also founded Amazon.com. “Now safely tucked away at our launch site in West Texas is the rarest of beasts, a used rocket. This flight validates our vehicle architecture and design.”

Blue Origin’s New Shepard capsule reached a maximum altitude of 329,839 feet and a speed of Mach 3.72, meaning 3.72 times the speed of sound, or about 2,854 mph, according a press release.

The release also laid out the details of the rocket booster landing. The rocket’s physical design first helped it to glide back toward the launch pad. Closer to the ground, the vehicle’s eight “drag brakes” reduced its terminal speed to 387 mph. Additional fins on the outside of the vehicle “steered it through 119-mph high-altitude crosswinds to a location precisely aligned with and 5,000 feet above the landing pad,” the release stated.

Finally, the BE-3 engine re-ignited “to slow the booster as the landing gear deployed and the vehicle descended the last 100 feet at 4.4 mph to touch down on the pad.”

The New Shepard crew vehicle also landed safely, guided down to Earth by parachutes.

Blue Origin has been somewhat secretive about the progress of its spaceflight vehicles and rockets; the company typically doesn’t announce test flights until they are already completed. Blue Origin intends to use the New Shepard vehicle for suborbital space tourism and as a microgravity science laboratory. (Suborbital means the vehicle can fly only to a lower altitude than is necessary to start orbiting the Earth — it would have to travel higher, and faster, to reach altitudes achieved by orbiting satellites or the International Space Station, for example.)

The company is also working on an orbital vehicle, which has been nicknamed “Very Big Brother.”

“We are building Blue Origin to seed an enduring human presence in space, to help us move beyond this blue planet that is the origin of all we know,” Bezos wrote in the blog post. “We are pursuing this vision patiently, step by step. Our fantastic team in Kent [Washington], Van Horn [Texas] and Cape Canaveral [Florida] is working hard not just to build space vehicles, but to bring closer the day when millions of people can live and work in space.”

Blue Origin is not the only company pursuing a reusable rocket design. The private spaceflight company SpaceX, founded by another Internet billionaire, Elon Musk, has made two efforts to set down a rocket on a landing pad after flight. But both times, the rocket came in too hard and too fast, and crashed on the landing pad.

On Nov. 24, Musk tweeted, “Congrats to Jeff Bezos and the BO team for achieving VTOL [vertical takeoff and landing] on their booster.” But, in a second tweet, he said, “It is, however, important to clear up the difference between ‘space’ and ‘orbit,’ as described well by https://what-if.xkcd.com/58/.”

SpaceX is not building a suborbital vehicle like New Shepard. Musk’s company’s robotic Dragon cargo capsule has already flown supplies to the International Space Station, and SpaceX has been selected by NASA to build a crew vehicle that will take people to the orbiting laboratory.

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Incredible Cross-section of the Saturn V Moon Rocket

The Incredible Saturn V

One Giant Screwup for Mankind

Stan Lebar

WHEN THE EAGLE LUNAR MODULE TOUCHED DOWN ON JULY 20, 1969, all eyes were on astronaut Neil Armstrong. But Stan Lebar’s ass was on the line.

A young electrical engineer at Westinghouse, Lebar had been tasked with developing a camera that could capture the most memorable moment of the 20th century – the Apollo 11 moon landing. The goal of the mission wasn’t merely to get a man on the moon. It was to send back a live television feed so that everyone could see it – particularly the Soviets, who had initiated the space race in 1957 by launching Sputnik. If the feed failed, Lebar, the designated spokesperson for the video setup, would turn the camera on himself at Mission Control in Houston and apologize to more than half a billion TV viewers. “It was my responsibility,” he says. “I’d have to stand up and take the hit.”

Building a camera that could survive the crushing g forces of liftoff and then function in near-weightlessness on the moon was only part of the challenge for Lebar. The portion of the broadcast spectrum traditionally used for video was sending vital ship data to Earth, and there was no room left for the standard black-and-white video format of the era: 525 scan lines of data at 30 frames per second, transmitted at 4.5 MHz. So Lebar helped devise a smaller “oddball format” – 320 scan lines at 10 fps, transmitted at a meager 500 kHz. Tracking stations back on Earth would take this so-called slow-scan footage, convert it for TV broadcast, and beam it to Mission Control, which would send it out for the world to see.

And that was the easy part. To ensure a direct transmission signal from the moon, NASA had to maintain stations in three continents – two in Australia (the Honeysuckle Creek Tracking Station near Canberra and the Parkes Radio Observatory surrounded by sheep paddocks west of Sydney); one at the Goldstone Deep Space Communications Complex in the Mojave Desert of California; and one at the Madrid Manned Flight Tracking Site in Spain. As Armstrong suited up for his first moonwalk, Dick Nafzger, the 28-year-old coordinator of the tracking stations’ TV operations, was as nervous as Lebar. Nafzger was the guy at Mission Control charged with monitoring ground equipment and the conversion of the slow-scan footage to US broadcast standards. “We were all going to be involved in something of monumental historic importance,” he says.

When Armstrong opened the hatch on the lunar module, stepped out onto the moon, and uttered his famous words about mankind’s giant leap, the tracking stations with a direct line on the Apollo‘s signal were the ones in Australia. The 200-foot-diameter radio dish at the Parkes facility managed to withstand freak 70 mph gusts of wind and successfully captured the footage, which was converted and relayed to Houston. “When the door opened, I knew the camera was working,” Lebar says, “It was pure elation.”

The world watched in awe as Armstrong took his first steps, and the camera engineers at Mission Control started popping the champagne corks. Amid the celebration, though, Lebar scrutinized the video, and his joy vanished. He had known the converted footage wouldn’t be as good as a standard TV signal. But as Armstrong bounded through the Sea of Tranquility, the astronaut looked like a fuzzy gray blob wading through an inkwell. “We knew what that image should look like,” Lebar says, “and what I saw was nothing like what I’d simulated. We looked at each other and said, ‘What happened?'”

With the rush of history upon him, Lebar let the concern pass. “As much as we may have found it disturbing,” he says, “the public didn’t seem to mind. Everyone seemed happy to see the guy on the moon.” Lebar never even saw the raw transmission; only the few tracking-station engineers did. But as they converted the feed for Mission Control and the worldwide audience, they also recorded it onto huge reels of magnetic tape that were promptly sent to NASA to be filed for safekeeping.

Not long ago, Lebar learned why the footage had looked like mush: The transfer and broadcast had degraded the image badly, like a third-generation photocopy. “What the world saw was some bastardized thing,” says Lebar, now 81. “Posterity deserves more than that.” Good thing the engineers in Australia recorded the raw feed. Now Lebar and a crew of seasoned space cowboys are trying to get that original footage and show it to the world.

There is just one problem: NASA has lost the tapes.

EVERY YEAR, NASA buffs and vets of the Apollo 11 mission reunite for a picnic near Canberra at the site of the Honeysuckle Creek station, which was shuttered in 1981. Seventy-year-old Bill Wood, an engineer at Goldstone during the moonwalk, describes the event as “a bunch of old guys in hard hats looking at an antenna while local TV follows us around.” Sometimes, talk turns to the effort to persuade the Australian government to erect a fitting commemorative on the site. But mostly, they just chat and show off old pictures and memorabilia.

During the 2002 reunion, one of the retirees produced a souvenir he had rediscovered in his garage: a 14-inch reel of magnetic tape from the Apollo era. They passed it around, marveling at how big and clunky it was, and then went back to their barbecue. The next year, a couple of Honeysuckle Creek vets showed up with keepsakes even more impressive: still photos they had snapped of the monitors in the station showing the moonwalk. The images displayed the original slow-scan footage, not the version converted for television.

“When we saw them, we realized they were significantly better than what had been seen in Houston,” says Colin Mackellar, a local minister and self-described space nut. He was only 12 during the Apollo 11 mission, but watching it on TV shaped his life. When he’s not tending his flock at Greystanes Anglican Church, he’s updating his Web site, honeysucklecreek.net, a tribute to the tracking station and the radio wonks he idolized.

Wood dug through his files and found an old Polaroid that showed the slow-scan footage as it appeared on a monitor at Goldstone. Like the Honeysuckle Creek photos, it was of a much higher quality than anyone had imagined. Curious and perplexed, he was determined to figure out whether the raw images of the moonwalk really were more crisp than what the world had seen in 1969.

More info on Stan Lebar

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