Category: space.com

A spacecraft that launched in 1995 to study the sun has discovered its 3,000th comet, further bolstering its credentials as history’s greatest comet hunter.

The Solar and Heliospheric Observatory (SOHO), a joint effort of NASA and the European Space Agency (ESA), spotted comet number 3,000 on Sunday (Sept. 13). The landmark discovery was pulled out of SOHO’s database by Worachate Boonplod of Thailand, NASA officials said.

“I am very happy to be part of a great milestone for SOHO’s comet project,” Boonplod said in a statement. “I would like to thank SOHO, ESA and NASA for making this opportunity possible, including other fellow comet hunters who I have learned a lot from.” [Sungrazing Comets: How They Dive-Bomb the Sun (Infographic)]

Boonplod is one of many laypeople around the world who sift through SOHO’s data in search of comets. Indeed, 95 percent of the spacecraft’s comet discoveries have been made by such citizen scientists, NASA officials said.

The dot in the cross-hairs is the 3,000th comet discovered by the NASA/European Space Agency Solar and Heliospheric Observatory (SOHO), as seen on Sept. 14, 2015. The comet was spotted in SOHO data by Worachate Boonplod of Thailand.
Credit: ESA/NASA/SOHO

“The people who have found comets represent a very broad cross section, as the program is open to anyone who has interest,” solar scientist Karl Battams, of the Naval Research Laboratory in Washington, D.C., who has run the SOHO comet-sighting website since 2003, said in the same statement. “There are scientists, teachers, writers. We have even had two 13-year-olds.”

SOHO’s main tasks involve studying the stream of particles flowing from the sun, known as the solar wind, and tracking huge explosions of superheated solar plasma called coronal mass ejections (CMEs). CMEs that hit Earth can spawn powerful geomagnetic storms that can disrupt satellite communications and power grids, as well as supercharge the northern and southern lights.

But SOHO has also proven extremely proficient at discovering and tracking “sungrazing” comets, which veer close to the sun (and sometimes plunge into the star).

“SOHO has a view of about 12.5 million miles [20.1 million kilometers] beyond the sun,” said SOHO mission scientist Joe Gurman, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “So we expected it might from time to time see a bright comet near the sun. But nobody dreamed we’d approach 200 a year.”

Studying sungrazers can reveal insights about the solar system’s early days, because comets are relics from the planet-forming period 4.5 billion years ago, NASA officials said. And tracing their paths around and near the sun can help researchers learn more about the solar magnetic field and the solar wind.

Before SOHO’s launch two decades ago, just 12 comets had been discovered by spacecraft, and a mere 900 others had been found by ground-based instruments, officials said.

SOHO spotted its 1,000th comet in 2005 and number 2,000 in December 2010.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Actors Sebastian Stan and Mackenzie Davis from the movie “The Martian” take a spin in NASA’s Modular Robotic Vehicle, or MRV, at the Johnson Space Center in Houston, Texas. Credit: collectSPACE.com/Robert Z. Pearlman

HOUSTON — NASA rolled out the red carpet for two “Red Planet” movie actors on Tuesday (Sept. 15), sharing a behind-the-scenes look at the space agency’s real journey to Mars with the stars from “The Martian.”

Sebastian Stan and Mackenzie Davis visited the agency’s Johnson Space Center in Houston, where the actors met with their characters’ real-life counterparts, took a spin in a prototype rover and spoke with the astronauts aboard the International Space Station.

The day was capped by a preview screening of the Ridley Scott-directed film, which opens in theaters on Oct. 2. [‘The Martian’: An Epic Space Film in Pictures]

“I think you can go back and tell the other cast members that you got closer to Mars than any of them have done,” said Ellen Ochoa, a shuttle-era astronaut and the director of the Johnson Space Center, referencing Stan and Davis’ visit and a Martian meteorite brought out for display.

In the 20th Century Fox film, which is based on the book by author Andy Weir, Stan plays Chris Beck, an astronaut and flight surgeon on the fictional near-future NASA Ares III mission, which accidentally strands crew member Mark Watney (Matt Damon) on Mars. Davis plays Mindy Park, a satellite communications engineer who works at Johnson Space Center in mission control.

“I certainly wish we could have gotten here before we did the movie, just because I am now really excited to do a sequel,” quipped Stan.

The two actors were joined by Ochoa and astronauts Rex Walheim and Mike Hopkins, among others, as they toured through a training mockup of the space station, sat inside a development mockup of the Orion spacecraft designed to take astronauts to Mars, shook hands with Robonaut 2 and took a ride on the Space Exploration Vehicle (SEV), a concept for a planetary rover similar to one created for the film.

“This isn’t a movie set obviously, so this is very real,” Stan said, reflecting on what he saw during the tour. “We were very lucky to have sets that were detailed enough to get close enough to what we are seeing here so that we could have more to play off of, because in order to capture even an inkling of the reality of what the guys go through day in and day out in the space station, we would need to sort of match a little bit of the detail that is in there.”

From inside the real mission control, the cast members had the opportunity to chat with space station commander Scott Kelly and flight engineer Kjell Lindgren in Earth orbit. [Matt Damon – Making ‘The Martian’ Was Amazing (Exclusive Interview)]

“I will ask you guys a question we get asked a lot,” Davis poised. “Having read ‘The Martian,’ how well do you think you could survive by yourself on Mars if under the same circumstances?”

“I think one of the things that really appeals to me [about the book] is how technically accurate, even though it is set in the future, that it seems to really try to be,” Lindgren replied. “Frankly, I don’t know I would have the know-how to MacGyver all the systems [needed] to scrub carbon dioxide, create oxygen and do all of the things that the main character Watney does — but I think it does really speak to the mission and the astronauts that we will send to Mars.”

“On the space station, we have tremendous support from the ground,” he explained. “When we have that mission to Mars, the astronauts that go there are going to have to have that depth of knowledge and expertise to be able to fix systems, have somebody who is a physician, maybe, that can help if anybody gets ill. There is going to have to be a lot of cross-training and technical know-how.”

Kelly, who on Tuesday hit the halfway point for his nearly yearlong mission to collect medical data to support future missions to Mars, thanked “The Martian” co-stars for their call.

“Hope the movie does well and we look forward to seeing it up here, hopefully soon,” he said.

“The Martian” cast members join their real-life counterparts for a roundtable discussion at the Johnson Space Center. Left to right: actors Mackenzie Davis and Sebastian Stan, astronaut and JSC director Ellen Ochoa, astronaut Mike Hopkins, and space station flight controller Pooja Jesrani.
Credit: collectSPACE.com/Robert Z. Pearlman

As a memento of their visit, Ochoa presented Stan and Davis with small flags that had flown to space aboard one of her space shuttle missions.

“It is really hard to get over that leap between something that is beautifully designed as a [movie set] replica and somebody you are talking to and you are like, ‘Oh, you’ve actually seen Earth from outer space,’” commented Davis. “Nothing really compares to the real thing.”

See more photos from “The Martian” cast members tour of NASA’s Johnson Space Center at collectSPACE.com.

Follow collectSPACE.com on Facebook and on Twitter at @collectSPACE. Copyright 2015 collectSPACE.com. All rights reserved.

Nichelle Nichols, who played Lt. Uhura on “Star Trek,” received an award on Aug. 31 from the organization Shades of Blue for her work as a NASA astronaut recruiter. Credit: Stefan Petryszyn

DENVER — “Beyond and beyond and beyond,” sings Nichelle Nichols. The 82-year-old actress-singer’s voice sails over draped round tables and wafts through the crowd of black ties and floor-length evening gowns.  

Nichols’ voice hits the back of the hangar housing the Wings Over the Rockies Air & Space Museum. Even the airplanes suspended from the ceiling rafters feel the resonance.

“‘I think you’re going to be a singer,’ he would say,” says Nichols, re-enacting the dialog she used to have with her voice teacher, “and I said, ‘No, I’m going to the moon, and I’m going to be an astronaut.’ [Giant Leaps: Top Milestones of Human Spaceflight]

“He said, ‘Someday, our astronauts are going to go to the moon‘ and, ‘Sing it higher!’” Nichols is working her way up through the octaves again; “Beyond and beyond and beyond.”  

Nichols accepted the Ed Dwight Jr. award here on Aug. 29 at the Shades of Blue Gala — but not for her role on “Star Trek” as Lt. Uhura, fifth in command aboard the Starship USS Enterprise. Neither does the award have anything to do with smooching Captain James T. Kirk (played by William Shatner) in a 1968 “Star Trek” episode, in what is widely cited as one of the first interracial kisses in American television history.

Rather, Nichelle Nichols is receiving the Ed Dwight Jr. award for the role she played in the 1970s and 1980s — recruiting new NASA astronaut candidates, many of them women and minorities. (Ed Dwight Jr. was the first African-American to be trained as an astronaut. He was selected in 1961 but never reached space.) 

“There were 321 (American) astronauts,” Shades of Blue president and founder Willie Daniels explains. “Twenty of them were African-American. Because this day in the country we have so many issues around the country causing strife and stress, to be able to look up and have true heroes — that means a lot.” Twelve astronauts and a Tuskegee airman are being honored at this event.  

Actress Nichelle Nichols (black dress, center) and other attendees of the Shades of Blue gala, which was held Aug. 31, 2015, at the Wings Over the Rockies Air & Space Museum in Denver.
Credit: Stefan Petryszyn

Daniels, a captain for United Airlines, founded Shades of Blue in 1999 in an attempt to address shortages in the United States’ science, technology, engineering and mathematics (STEM) workforce. The organization runs aeronautics summer camps, fly-days and mentorship programs supporting students interested in pursuing aviation and aerospace careers. Shades of Blue currently has 2,000 students under its wing, ranging in age from kindergartners all the way to college kids. The goal is to reach 250,000 students by 2020.

“Last year, it was awesome,” says seventh-grader Lamir Brewster. “They had tours, showed us planes and their engines.” The aspiring pilot’s favorite part was “going up in a Cessna.” 

“When I was a kid, astronauts were [in] Flash Gordon comic books,” explains Guion Bluford Jr., who grew up in the 1940s and ’50s. “As a kid, I thought they’d never select me, so I went into aerospace.” Bluford became a colonel in the U.S. Air Force. Then Nichols recruited him for NASA’s space shuttle program, and he went on to earn the distinction of being the first African-American in space.

Seventh-grader Lamir Brewster, who aspires to be a pilot, attended the Shades of Blue gala on Aug. 31, 2015, at Denver’s Wings Over the Rockies Air & Space Museum in Denver.
Credit: Susanna Speier

“I’m a direct beneficiary of what they’ve done,” says NASA astronaut Victor Glover, gesturing to former shuttle astronauts Winston Scott, Stephanie Wilson and Joan Higginbotham. 

Glover, one of the original students to go through the Shades of Blue program, is wearing a ceremonial white Air Force jacket and a black bow tie. Slides of Mars, Uranus and nebulae are flashing on the large screen to the right of the stage. [Our Solar System: A Photo Tour of the Planets]

“I applied in 2007 for the 2009 class after test-pilot school, recalls Glover. “I was inspired by Pam Melroy, one of the few female shuttle commanders. Watching Pam Melroy speak was the professional ‘Wow, this is more than just a childhood fantasy; this is definitely something I want to see as part of my career’ moment.

“I looked at Winston and at [former shuttle commander and current NASA chief] Charlie Bolden,” Glover adds. “I’d read their biographies and saw they were doing similar things. I’ve been a fan of NASA and of astronauts since I was a kid. I didn’t realize how close I was, careerwise. Guys who had gotten there from the military — we had something in common. I have done the lion’s share of those things those guys had done to be eligible.”  

Glover applied in 2007 and wasn’t accepted. He applied again in 2009 and made it into the newest class of NASA astronaut candidates, which was selected in 2013. 

That class is composed of four men and four women.

“If I put that in front of anyone, they accept it today,” Glover explains. “It is exceptional, even though the country is half women. My daughters don’t see the exception. They just see that it’s right. But it is very special and hopefully will continue. We’ve got ethnic diversity, gender diversity, and it’s an exceptional class.”

“I was shyer than you when I was your age,” Janette Epps assures a young and noticeably star-struck girl. The girl is wearing a pale pink dress covered with black polka dots. She is holding a drawing of Lt. Uhura in her hand. 

Like Glover, Epps is in the current 2013 class, training to fly Russia’s Soyuz spacecraft and live and work aboard the International Space Station. She has a bachelor’s degree in physics, studied aerospace in graduate school and worked for the Ford Motor Company before moving on to the CIA. Astronaut Leland Melvin, also in attendance, encouraged her to apply to be an astronaut. Melvin himself was encouraged by Bolden to apply. 

“Everything is hard until you know it,” Epps tells the girl in the polka-dot dress. “This fighter pilot I know, he puked every time [he flew]. He puked every time! If you love it, you do it!”

Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Artist’s depiction of NASA’s Orion spacecraft mated to a European-built service module. Credit: NASA/Sierra Nevada Corp,

The first manned flight of NASA’s Orion spacecraft, which is being built to help humanity explore Mars and other distant destinations, may be delayed by two years, until 2023, agency officials announced today.

Orion’s first crewed sojourn, known as Exploration Mission 2 (EM-2), is officially targeted for launch in August 2021. But after conducting a thorough review of the Orion program last month, NASA is now acknowledging the possibility of a delay for EM-2, saying the liftoff will occur “no later than April 2023.”

Engineers and technicians are still working toward the August 2021 goal, but hitting that target is unlikely, said NASA Associate Administrator Robert Lightfoot. [The Orion Capsule: NASA’s Next Spaceship (Photos)]

“It’s not a very high confidence level, I’ll tell you that, because of the history — the things we see historically pop up,” Lightfoot told reporters during a teleconference today (Sept. 16). Such factors include complications arising from the reuse of equipment from flight to flight and software development, he added.

“We’re not seeing any issues in those areas, but we have to account for those, because we have a lot of runway in front of us,” Lightfoot said.

NASA is developing Orion, which can support a crew of four for up to 21 days, as well as a megarocket called the Space Launch System (SLS) to enable the crewed exploration of deep space. The capsule will get astronauts to space and back to Earth, and it will carry them on missions in Earth-moon space. (Long journeys, such as the trek to Mars, will feature habitat modules for crewmembers to live in.)

“Orion is a predominant, first key player in really allowing us to move human presence out of low Earth orbit,” said Bill Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Directorate.

Orion blasted off for the first time last December, riding a United Launch Alliance Delta IV Heavy rocket on a successful unmanned mission called Exploration Flight Test 1 (EFT-1). SLS won’t reach space until 2018, when it sends an uncrewed Orion winging around the moon on the weeklong Exploration Mission 1 (EM-1).

EM-2’s destination and duration aren’t finalized yet, but Orion will carry astronauts on the mission. Indeed, the main goals include making sure that the capsule’s crew systems are ready to perform in deep space. The next flight after that, Exploration Mission 3 (EM-3), could be pretty much an operational flight; it may send astronauts out to rendezvous with a chunk of a near-Earth asteroid that a robotic probe has delivered to lunar orbit. (NASA wants this asteroid visit to take place by 2025.)

A possible delay for EM-2 won’t necessarily affect the schedules for either EM-1 or EM-3, Lightfoot and Gerstenmaier said.

NASA will spend $6.77 billion to get Orion ready for EM-2, from October 2015 through the mission’s completion, Lightfoot said. A commitment of more funding could conceivably allow the agency to accelerate EM-2’s schedule, he added.

And some lawmakers would like more money for Orion and SLS — including Rep. Lamar Smith, R-Texas, chairman of the House of Representatives’ Science, Space, and Technology Committee.

“Once again, the Obama administration is choosing to delay deep-space exploration priorities such as Orion and the Space Launch System that will take U.S. astronauts to the moon, Mars and beyond,” Smith said in a statement today in response to news of the possible EM-2 delay.

“We must chart a compelling course for our nation’s space program so that we can continue to inspire future generations of scientists, engineers and explorers,” Smith said. “I urge this administration to follow the lead of the House Science, Space and Technology Committee’s NASA Authorization Act to fully fund NASA’s exploration programs.”

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Last week, NASA announced the top 30 finalists for their 3D-Printed Habitat Challenge.

The contest is meant to encourage innovation in the area of 3D-printing and to develop a shelter on Mars using local materials, such as Martian soil, or recycled materials from spacecraft.

Road Trip! 10 Tricked-Out Mobile Homes Rev Up

There are several cool designs, but one team from France either didn’t submit their design on time or weren’t invited. (Inhabitat and Fabulous both claim that only American teams were allowed to apply, but I found no mention of that in the rules.) [10 Ways 3D Printing Is Transforming Space Travel]

Nonetheless, the Sfero Bubble House design from Fabulous is compelling. (They named it Sfero by combining the words “Sphere,” “Iron” and “Water.”)

Construction of the habitat would be begin with a long pole that would drill into the ground and from which two robotic arms would extend. One arm would suck up and sort material from the surface, while the other one would use the material to construct a dome overhead.

Printed from Martian soil, the home is partially buried underground so that only the top floor is on the surface. In this space, the astronauts could maintain an indoor garden and workspace. The lower floors would be reserved for sleeping, with all floors connected by a spiral staircase.

Dream This Up: Structures Meld Art And Design

The structure’s exterior walls would be made of two shells sandwiching water melted from permafrost, which would serve as a radiation barrier.

The team recommends building the structure in the crater Gale, which is known to contain large deposits of iron.

via Inhabitat

This article was provided by Discovery News.

Blue Origin founder Jeff Bezos unveils the company’s plans to launch a fleet of reusable rockets and spacecraft from Cape Canaveral in Florida during a media event on Sept. 15, 2015. Credit: Blue Origin

Amazon.com founder and CEO Jeff Bezos isn’t the only billionaire who wants to put his stamp on spaceflight.

Bezos announced Tuesday (Sept. 15) that Blue Origin, the private spaceflight company he established in 2000, will manufacture and launch a fleet of reusable vehicles from Florida’s Cape Canaveral Air Force Station, with the first flights scheduled to begin by the end of the decade.

The news is creating quite a stir. But so are the activities of spaceflight companies headed by Elon Musk, Richard Branson and Paul Allen — all billionaires themselves. Here’s a brief rundown of how the megarich are helping shape the exploration and exploitation of space. [Watch Blue Origin Announce Its Florida Launch Plans]

Jeff Bezos: Blue Origin

Blue Origin is developing reusable rockets and spacecraft to launch astronauts to both suborbital and orbital space. Reusability could spur the next big leap in crewed space exploration by dramatically cutting the cost of flight, advocates of the technology say.

Blue Origin launched a successful test flight of its New Shepard suborbital vehicle this past April from a facility in West Texas, which will also host future launches of the craft. The company’s biconic orbital vehicle, by contrast, will lift off from Cape Canaveral, atop a new rocket that Jeff Bezos (who is worth $34.8 billion, according to a recent estimate by Forbes magazine) and his colleagues are calling “Very Big Brother.”  

Very Big Brother will launch and land vertically and reuse its first stage. The rocket will be powered by the new BE-4 engine, which Blue Origin is developing with launch provider United Launch Alliance (ULA). The BE-4 will also be incorporated into ULA’s reusable Vulcan rocket.

Elon Musk: SpaceX

PayPal co-founder Elon Musk (who has a net worth of $12 billion) set up SpaceX in 2002, with the explicit aim of helping humanity colonize Mars. Like Bezos, Musk is a big proponent of reusable rockets, saying a fully and rapidly reusable launch system could make a Red Planet settlement economically feasible.

So SpaceX is working hard to develop reusable rockets; the company has made two attempts to land the first stage of its Falcon 9 rocket on a drone ship in the Atlantic Ocean following cargo launches to the International Space Station. (SpaceX holds a $1.6 billion deal to fly at least 12 robotic resupply missions to the orbiting lab for NASA using the Falcon 9 and the company’s Dragon capsule.)

Both of these landing attempts, which occurred in January 2015 and April 2015, nearly succeeded; the Falcon 9’s first stage hit the ship on both occasions but toppled over and exploded. A June launch of a Falcon 9 rocket also exploded just after liftoff, with SpaceX has traced the failure to a faulty strut. The company plans to return to flight in the fall. [Watch SpaceX’s near-miss April 2015 rocket-landing attempt]

SpaceX also won a $2.6 billion NASA contract to fly astronauts to and from the space station using a crewed version of Dragon. The agency awarded Boeing $4.2 billion as well to finish developing its CST-100  capsule, which is now known as Starliner; NASA hopes that one or both private space taxis will be up and running by 2017.

SpaceX is also working on a powerful rocket called the Falcon Heavy, which will handle weighty payloads destined for Earth orbit and also send spacecraft toward Mars and other distant destinations. The Falcon Heavy’s maiden flight should take place in 2016, company representatives have said.

Richard Branson: Virgin Galactic

British entrepreneur Richard Branson ($4.8 billion) founded Virgin Galactic in 2004, with an eye toward creating a new tourism industry in suborbital space.

The company is developing a six-passenger vehicle called SpaceShipTwo, which will be lofted to an altitude of about 50,000 feet (15,000 meters) by a carrier aircraft known as WhiteKnightTwo. At that point, SpaceShipTwo will be dropped and turn on its rocket engine, blasting itself upward to suborbital space.

Customers will experience a few minutes of weightlessness and see Earth against the blackness of space before coming back down for a runway landing, Virgin Galactic representatives have said. A ticket to ride the space plane currently sells for $250,000.

SpaceShipTwo is in the test phase and experienced a tragic setback last year during the vehicle’s fourth rocket-powered flight. SpaceShipTwo broke apart in mid-air on Oct. 31, killing co-pilot Michael Alsbury and injuring pilot Peter Siebold. The accident occurred because Alsbury unlocked the space plane’s “feathering” re-entry system too soon, investigators with the National Transportation Safety Board have determined.

Paul Allen: Stratolaunch Systems

Paul Allen ($17.5 billion), who co-founded Microsoft with Bill Gates, is another billionaire with a longstanding interest in space. Allen helped bankroll SpaceShipOne, an experimental vehicle that won the $10 million Ansari X Prize in 2004 after getting to space and back twice within the span of five days.

SpaceShipOne, which became the basis for Virgin Galactic’s SpaceShipTwo, was designed by Scaled Composites, a California-based company led by famed aerospace engineer Burt Rutan. Allen and Rutan teamed up again in 2011 to form Stratolaunch Systems, which aims to launch satellites (and, eventually, crewed vehicles) beneath an enormous airplane — a setup designed to make spaceflight cheaper and more efficient.

That plane, in fact, will be the largest aircraft ever built, with a wingspan of 385 feet (117 meters), Stratolaunch representatives have said. The company aims to fly the huge plane for the first time in 2016.

Stratolaunch Systems is a subsidiary of Vulcan Aerospace, a company Allen unveiled in 2015. Vulcan Aerospace oversees the space projects of Vulcan, Inc., which Paul Allen founded with his sister Jody in 1986.

Asteroid mining, too

Billionaires are also making a splash by investing in, rather than creating, space companies.

For example, the asteroid-mining company Planetary Resources, which announced its existence in 2012, counts five billionaires among its investors — Google executives Larry Page ($29.7 billion) and Eric Schmidt ($9.1 billion), former Google board member K. Ram Shriram ($1.9 billion), real-estate developer Ross Perot, Jr. ($1.75 billion) and software architect Charles Simonyi ($1.4 billion).

Another Planetary Resources investor, filmmaker James Cameron, is worth about $700 million.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

The Cassini spacecraft’s close view of the southern terrain of Saturn’s moon Enceladus, which contains a massive global ocean under its surface, scientists recently confirmed. Credit: NASA/JPL-Caltech/Space Science Institute

Saturn’s moon Enceladus is an active water world with a global body of water sloshing around deep below its icy crust, scientists have confirmed.

Gorgeous geysers of water have been observed erupting from Enceladus’ surface, providing direct evidence of a reservoir of the life-giving liquid below the surface. But scientists were unsure if the satellite contained an entire ocean, or just a small body of water concentrated at its south pole.

The smoking gun is the very slight wobble that Enceladus displays as it orbits Saturn. This unsteady motion is effectively the result of water sloshing around inside Enceladus, and could not appear if the moon were made of ice all the way to its core. Instead, the moon must contain a complete ocean layer, according to new research that relied on more than seven years of images taken by NASA’s Cassini space probe. [Photos of Enceladus, Saturn’s Icy Moon]

“This was a hard problem that required years of observations, and calculations involving a diverse collection of disciplines, but we are confident we finally got it right,” Peter Thomas, lead author of the new work and a Cassini imaging team member at Cornell University, said in a statement from the Cassini imaging team.

Thomas and his colleagues studied images of Enceladus to precisely measure changes in its rotation, then ran several simulations to determine how the interior of the moon would affect those wobbles.

A slight wobble in Saturn’s moon Enceladus reveals that the world contains a global ocean beneath its icy crust. Some of this ocean spurts out into space from the southern polar region.
Credit: NASA/JPL-Caltech/SSI

Wobbly wet moon

Not long after NASA’s Cassini mission arrived at Saturn, it detected signs of icy plumes spurting from the southern hemisphere. Further observation suggested that the fractures at the south pole, dubbed “tiger stripes,” were the source of the geysers, allowing material from the interior to leak into space.

Originally, scientists thought only a small local sea existed beneath the icy crust, supplying the plumes with material. Gravitational mapping of the world collected during Cassini’s close passes suggested that the sea might be global, but could not be confirmed.

Following an independent line of research, Thomas and his team analyzed more than seven years of images of Enceladus, carefully mapping features on the moon across hundreds of images to measure changes in its rotation. They found that the tiny world has a small but measurable wobble as it orbits the ringed giant Saturn.

The team then ran several simulations to determine how the wobble would affect the moon if it had a variety of interiors, including one that was completely frozen. They found that the wobble was explained only if Enceladus contained a global ocean beneath its icy crust.

“If the surface and core were rigidly connected, the core would provide so much dead weight the wobble would be far smaller than we observe it to be,” co-author Matthew Tiscareno, a Cassini participating scientist at the SETI Institute in California, said in the same statement.

“This proves that there must be a global layer of liquid separating the surface from the core.”

The mystery of Enceladus’ ocean

How Enceladus could have maintained a liquid ocean for so long remains a mystery. Thomas and his colleagues suggested ideas for a future study that might help resolve the question, including the idea that tidal forces produced by the gravity of Saturn could generate more heat within the moon than previously anticipated.

“This is a major step beyond what we understood about this moon before, and it demonstrates the kind of deep-dive discoveries we can make with long-lived orbiter missions to other planets,” said co-author Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Colorado. Currently, NASA scientists are considering sending a spacecraft to Enceladus as early as 2021.

“Cassini has been exemplary in this regard,” Porco said.

The research was published online in the journal Icarus.

Follow Nola Taylor Redd on Twitter @NolaTRedd or Google+. Follow us @Spacedotcom, Facebookor Google+. Originally published on Space.com.