Tag: space

[unable to retrieve full-text content]A partial solar eclipse occurred on Sept. 13, 2015. See photos from the event by skywatchers in South Africa and a satellite in space.

Jon Adams’ Web comic, “Chief O’Brien,” follows the exploits of Star Trek: The Next Generation’s Chief O’Brien, responsible for beaming crewmembers on and off of the ship. A new graphic novel delves into O’Brien’s day-to-day life. Credit: Jon Adams

While fans of “Star Trek” love to talk about “away missions” to the surface, a new Kickstarter campaign asks you to consider the lonely crewmember left behind who must beam the crew to and from the planet.

Chief O’Brien, played by Colm Meaney in “Star Trek: The Next Generation” (TNG) and “Star Trek: Deep Space Nine”, was responsible for the crew’s Transporter needs, and he seemed to spend most of his time in the TV series standing on the TNG transporter room, waiting for instructions. After running a parody Web comic on the topic called “Chief O’Brien At Work” since 2014, author Jon Adams is creating a graphic novel based on the Chief’s workday in the “Star Trek” universe.

“If you’ve ever felt the existential angst of a worthless job, step aside, because someone else feels it even more so, and his name is Chief O’Brien,” the Kickstarter crowdfunding page reads. “Watch him stand alone for hours on end, hoping today will be the day he finally gets to transport someone somewhere.” [Star Trek: The Art of Juan Ortiz’ (Gallery)]

The Web comic has already garnered the attention of “Star Trek” stars Wil Wheaton (from “TNG”) and Jeri Ryan (“Star Trek: Voyager”), who each shared it with fans on Tumblr and Google+, respectively.

Meaney has also seen a copy of the comic at least once, according to a picture on the Kickstarter page. A fan printed out one of the strips for Meaney to sign at a comic convention.

With eight days to go in the crowdfunding campaign, the book has more than doubled its initial $15,000 goal (reaching $36,675 as of this post). The softcover book will be 128 pages long and will include brand-new comics — including “scenes outside of the transporter room,” the Kickstarter page promises.

Jon Adams’ Web comic, “Chief O’Brien,” follows the exploit of the titular Star Trek: The Next Generation character.
Credit: Jon Adams

Adams is also the author of a comic called “Truth Serum,” which was nominated for two Eisner awards given for achievement in American comic books. He has written cartoon shorts for MTV and designed several books, including “Cyborg 009” and “The Joyners in 3D.”

You can contribute to the Kickstarter campaign here: 
https://www.kickstarter.com/projects/1439753165/chief-obrien-at-work-graphic-novel

Follow Elizabeth Howell @howellspace, or Space.com @Spacedotcom. We’re also on Facebook and Google+. Original article on Space.com.

This composite image of Jupiter’s moons Io (top right) and Europa shows three volcanic plumes on Io’s surface, the largest 190 miles (300 kilometers) high. Two smaller plumes are also visible on the edge of the disk and along the illuminated border. Credit: NASA/JHU Applied Physics Laboratory/Southwest Research Institute

Something strange is happening on Io: The Jupiter moon’s vigorous volcanoes are mysteriously offset from where scientists expected, and its underground magma oceans may be the cause.

A new model suggests that worlds caught in an intense push and pull of gravity, like the volcanic moon Io, are likely to have below-ground oceans of magma or water that stick around for a long time — in the water’s case, providing a potential hotspot for the development of life.

“This is the first time the amount and distribution of heat produced by fluid tides in a subterranean magma ocean on Io has been studied in detail,” Robert Tyler, the lead author of the new research from the University of Maryland, College Park and NASA’s Goddard Space Flight Center, said in a statement. “We found that the pattern of tidal heating predicted by our fluid-tide model is able to produce the surface heat patterns that are actually observed on Io.” [More Photos of Io: Jupiter’s Volcanic Moon]

Fiery Io

Jupiter’s moon Io is the most volcanically active body in the solar system. Its hundreds of volcanoes are caused by heat coming from the gravitational push and pull between Jupiter and the nearby moon Europa. The coming and going of Europa as it orbits, and Jupiter’s steady influence, pulls Io into an oval orbit and flexes it, creating heat inside the moon due to friction.

Earlier models of the process envisioned a solid, claylike Io changing shape under the gravitational influence, but they had a strange flaw: the volcanoes were predicted to form over the spots with the greatest internal heating, but on the real Io the volcanoes form much farther east. When the discrepancy was published, in 2013, the researchers wrote that the moon might be rotating faster than expected or have a spongy magma ocean.

“It’s hard to explain the regular pattern we see in so many volcanoes, all shifting in the same direction, using just our classical solid-body tidal heating models,” Wade Henning, a co-author on the study and also from University of Maryland and NASA Goddard, said in the statement.

Half the story

This new model, published by a team including the lead author of the 2013 paper, considers the added effects of an ocean layer below the surface of the moon formed with a mixture of molten and solid rock. The molten rock would swirl and rub against the solid rock under gravity’s influence and generate additional heat, the researchers said.

The combination of these fluid effects, plus the flexing solid material, could explain the observed volcano patterns.

“The fluid tidal heating component of a hybrid model best explains the equatorial preference of volcanic activity and the eastward shift in volcano concentrations, while simultaneous solid-body tidal heating in the deep-mantle could explain the existence of volcanoes at high latitudes,” Henning said. “Both solid and fluid tidal activity generate conditions that favor each other’s existence, such that previous studies might have only been half the story for Io.”

Implications for life on moons

While an underground magma ocean is certainly inhospitable, other moons in the solar system have liquid water seas below the surface, like icy Europa and Saturn’s moon Enceladus, which are considered possible habitats for life. This new model suggests that liquid oceans might stick around for longer and also be more common beneath tidally stressed satellite surfaces. With energy sources and raw materials available, a long-lasting liquid water ocean could be a good place for life to develop.

Such oceans could begin to resonate with the push and pull of gravity, generating heat through tidal flow and lasting for a long time, said Christopher Hamilton, a co-author on the study from the University of Arizona, Tucson. “Therefore the mystery may be not how such subsurface oceans could survive, but how they could perish,” he said. “Consequently, subsurface oceans within Io and other satellites could be even more common than what we’ve been able to observe so far.”

The research was detailed in June in the Astrophysical Journal Supplement Series.

Email Sarah Lewin at slewin@space.com or follow her @SarahExplains. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Artist’s concept of a robot-run space transportation hub at geosynchronous orbit, about 22,370 miles (36,000 kilometers) from Earth. Credit: DARPA

The future of spaceflight involves building, refueling and repairing spacecraft in a depot far from Earth, all without the aid of human hands, officials with the United States military say.  

The Defense Advanced Research Projects Agency (DARPA) is developing a highly capable robotic arm that could make such a space “transportation hub” possible in the relatively near future, said former NASA astronaut Pam Melroy, deputy director of DARPA’s Tactical Technology Office.

“We think that these capabilities — space capabilities — are not just about a single monolithic satellite with a few capabilities, but instead about a vibrant, robust ecosystem that involves transportation, repair, refueling, upgrading, [and] in situ construction,” Melroy said Thursday (Sept. 10) at DARPA’s “Wait, What? A Future Technology Forum” in St. Louis. [Incredible Technology: Space Travel and Exploration]

“Look at the great seafaring port cities in the world for inspiration, and imagine a port of call at 36,000 kilometers,” she added.

Thirty-six thousand kilometers (22,370 miles) is the distance from Earth at which satellites fly in geosynchronous orbit, or “GEO” for short. Spacecraft at GEO — which include most operational telecommunications satellites — complete one lap in the same amount of time it takes Earth to rotate once on its axis, and therefore appear to “hover” over one spot on the planet all the time.

It makes much more sense to build a transformative transportation hub at GEO than at low-Earth orbit (LEO), which lies at an altitude between 186 miles and 373 miles (300 to 600 km), Melroy said.

For one thing, orbital velocity at GEO is lower, reducing the risk of serious collisions with space junk. GEO is also a much more stable orbit, because satellites located there are not nearly as affected by atmospheric drag. Whereas spacecraft at LEO (such as the International Space Station) will fall back to Earth within 25 years or so unless orbit-boosting maneuvers are performed, objects at GEO will stay put on their own for up to 1 million years, Melroy said.

“We think this sounds like a really interesting place to put infrastructure, because it’s such a stable place,” she said.

Radiation levels so far from Earth — GEO lies about 10 percent of the way from Earth to the moon — are too high for astronauts to tolerate safely over long durations, so this future facility would be run by robots, Melroy added.

The key to making all of this happen therefore lies in advanced space robotics — “robotic arms very much like the one that was used to build the International Space Station, but with greater levels of automation and safety,” Melroy said.

“DARPA is building just such a robotic arm,” she added. “We think this is a critical capability to building a transportation hub that allows transporation to and from the Earth’s surface, from low-Earth orbit to GEO, and even beyond Earth orbit.”

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

Xtronaut, which comes with everything you see here, aims to teach gamers seven and up about the technical and political hurdles involved with exploring the solar system. And also to raise an education and public outreach budget for NASA’s Osiris-Rex asteroid sample return mission. Credit: Dante Lauretta

WASHINGTON — The head of NASA’s Osiris-Rex asteroid sample-return probe plans to crowdfund a public outreach budget for the mission on Kickstarter by selling a card game in which players compete to build their own space missions.

The game, Xtronaut, was designed by Dante Lauretta, a University of Arizona Tucson professor and principal investigator for Osiris-Rex: A roughly $1 billion NASA New Frontiers mission set to launch in September 2016 and return an asteroid sample to Earth in 2023.

NASA missions historically reserved a slice of their budgets for education and public outreach, or EPO: Essentially, promoting the mission to the public through experts directly involved with the program. However, Osiris-Rex’s EPO budget got deleted in 2013 as part of a broader federal policy change initiated that year to consolidate U.S. education spending within the Department of Education.

“This happened right as we were going through our confirmation review — where our baseline budget is set,” Lauretta wrote in a Sept. 8 email. “Since this policy was in effect, the agency made the decision to remove EPO as an element of the mission.”

Osiris-Rex lost its EPO funding despite the fact that Congress has never gone along with the administration’s proposal to move EPO money for NASA science missions out of the agency, agency spokesman Dwayne Brown confirmed Sept. 8. Reports attached to omnibus spending bills that funded the government in 2014 and 2015 directed NASA to reserve a small slice of the roughly $5 billion approved for the agency’s Science Mission Directorate for EPO, including some $40 million this year.

The Xtronaut Kickstarter campaign launched Sept. 12 and run for 30 days. The minimum contribution is $5 and Lauretta wants to raise at least $15,000. Stretch goals run through $75,000 and mostly unlock expansions to the 90-card deck that comes with the base game.

In the game, players compete to become the first to earn 100 points by launching robotic spacecraft to various solar system destinations. Players can impede one another with so-called “action cards” that simulate the various political pitfalls NASA missions often confront as they strive to get off the ground.

To crank out early versions of the game for play testing, Lauretta founded Xtronaut Enterprises with Michael Lyon, a venture capitalist who has also invested in the piloted Lynx suborbital spaceplane under construction at XCOR Enterprises in Mojave, California. Xtronaut Enterprises also got financial contributions from the aspirant asteroid mining outfit Planetary Resources, Redmond, Washington, and cable and internet giant Cox Communications of Atlanta, Lauretta wrote in his email. He declined to quantify the total investment to date.

Xtronaut includes many of the real-life perils of space-mission development.
Credit: Dante Lauretta

According to the Xtronaut Kickstarter page, United Launch Alliance of Denver also backed the project. Osiris-Rex will launch on Atlas 5 from Cape Canaveral Air Force Station in Florida.

Xtronaut wouldn’t be the first card game based on a NASA mission. The team behind the Fermi Gamma-ray Space Telescope, which launched in 2008, created the Fermi Race Card Game. As with Xtronaut, Fermi Race pits players against one another in a competition to build a spacecraft bedeviled by political and technical snafus, and the occasional bit of bad luck.

To learn more about the Xtronaut game, or to contribute, visit: 
https://www.kickstarter.com/projects/827615927/xtronaut-the-game-of-solar-system-exploration

This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.

Artist’s view of two Galileo satellites released into orbit. – See more at: http://spacenews.com/soyuz-rocket-places-pair-of-galileo-satellites-into-orbit/#sthash.5eHgPHZH.dpuf Credit: ESA

PARIS — A Europeanized Russian Soyuz rocket equipped with a Fregat upper stage on Sept. 11 successfully placed two European Galileo positioning, navigation and timing satellites into medium-Earth orbit, with two more scheduled for launch in December aboard a Soyuz.

The Sept. 10 launch from Europe’s Guiana Space Center on the northeast coast of South America and subsequent Sept. 11 release into orbit brings to 10 the number of Galileo navigation satellites deployed, with 20 more to go to complete the system by 2020. Assuming the December launch occurs as scheduled, the Galileo system will have 12 functioning spacecraft in orbit by early 2016.

The European Space Agency, which is managing Galileo’s development on behalf of the European Commission, plans to launch four more Galileo satellites in late 2016 aboard a heavy-lift Ariane 5 rocket once a purpose-built adapter carrying the four Galileo spacecraft has been validated. Work on the adapter is scheduled for completion by next spring.

In a press briefing before the launch, ESA Navigation Director Didier Faivre said OHB SE of Bremen, Germany, which is building 22 Galileo satellites, has demonstrated its ability to deliver satellites at the forecast rate.

A Europeanized Soyuz lifted off Sept. 10, placing two Galileo satellites in orbit early Sept. 11.
Credit: ESA

The Ariane 5 launch in 2016 will be the sole Galileo launch that year. In 2017, one Ariane 5 and one Europeanized Soyuz will carry a total of six Galileo satellites. In 2018, the last of the current batch of OHB-built satellites will launch aboard the third and final Ariane 5 rocket contracted for the work.

With four in-orbit-validation (IOV) satellites also in orbit, and despite the fact that one cannot fully function because of a power glitch, ESA and the European Commission will have 26 satellites at their disposal by 2018.

Paul Flament, a Galileo manager at the European Commission, told the briefing that the commission expects to be ordering at least four more satellites in the coming months, in time to have them launched an in service by 2020.

“Mathematically, an order of four satellites would be enough” to complete the 30-satellite constellation, Flament said. “But there is a problem with one of the IOV so we may want to order more than four. I cannot give you a precise figure yet.”

Apparently still undecided is whether the commission will order four more spacecraft from OHB, which would reduce the cost of the new contract, or will open a fresh competition likely to include Airbus Defence and Space and Thales Alenia Space in the bidding process.

European government and industry officials have said they may wish to use the next Galileo satellite order as a way of introducing elements of a second-generation system. Doing so would also make it more likely that OHB will have competition in future Galileo satellite orders. Dual sourcing of suppliers is a European Commission goal.

Faivre and Javier Benedicto, ESA’s Galileo project manager, said during the briefing that the two Galileo satellites launched into a bad orbit following a defect in the Soyuz rocket’s Fregat upper stage have been maneuvered into a position that allows their use in the overall Galileo constellation.

A relatively modest adjustment to the Galileo ground network will be needed to accommodate the unplanned orbit, but otherwise the satellites will be able to provide the planned navigation and search-and-rescue signals.

As a result of the August problem, the European Commission decided that, starting with the most recent launch, it will insure the launch of all future Galileo satellites. It is rare, although not unprecedented, for governments to insure their space launches.

The Sept. 11 launch placed the two Galileo satellites into a near-circular orbit with an altitude of 29,930 kilometers — the satellites will be lowered into their final operating orbit in the coming days — and an inclination of 57.4 degrees relative to the equator.

Faivre said each OHB satellite now being launched cost about 40 million euros ($44 million), with the Soyuz rocket costing ESA about 80 million euros.

This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.

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This mosaic of the new high-resolution Pluto images shows 1,000 miles (1,600 km) of the dwarf planet’s surface, as taken from 50,000 miles (80,000 km) away during New Horizons’ closest approach. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

NASA’s New Horizons spacecraft beamed home incredible new images of Pluto, scientists found a giant buried ice sheet on Mars and Elon Musk chatted with Stephen Colbert about the future of spaceflight. Here are Space.com’s top stories of the week. 

Pluto in breathtaking new detail

Supersharp new images just received from NASA’s New Horizons spacecraft show a stunning variety of complicated surface features on Pluto. [Full Story: New Photos of Pluto Show a World More Complex and Beautiful Than Ever]

Huge ice sheet found on Mars

A giant slab of ice as big as California and Texas combined lurks just beneath the surface of Mars between its equator and north pole, researchers say. [Full Story: Gigantic Ice Slab Found on Mars Just Below the Planet’s Surface]

Elon Musk chats with Stephen Colbert

Elon Musk appeared on “The Late Show with Stephen Colbert” Wednesday night (Sept. 9) to talk about dropping nuclear bombs on Mars, the future of rocket travel and a creepy, snakelike robot for electric-car owners. [Full Story: Stephen Colbert Says Elon Musk Is Either a Supervillain or a Superhero] 

NASA still considering lander for Europa mission

NASA’s upcoming mission to Europa will primarily be a flyby affair, but it may also include a small lander that touches down on the potentially life-harboring Jupiter moon. [Full Story: NASA’s Europa Mission May Land on Ocean-Harboring Moon] 

NASA developing ‘hedgehog’ robot for comet, asteroid exploration

Researchers tested two “hedgehog” robot prototypes this summer to get an idea of the machines’ potential to explore space locations inaccessible to conventional rovers. [Full Story: Hopping ‘Hedgehog’ Robot Could Explore Comets and Asteroids] 

Is this how we’ll get samples back from Mars?

A mission that uses SpaceX’s Dragon capsule to help bring chunks of Mars rock back to Earth for analysis could launch as early as 2022, scientists say. [Full Story: ‘Red Dragon’ Mars Sample-Return Mission Could Launch by 2022] 

Stunning view of alien planets being born

When an image of the extrasolar system HL Tau was unveiled last year, it sparked controversy over whether or not grooves in the disk of dust surrounding the star could be explained by the presence of newly formed giant planets. Now, a new paper suggests that the orbit of those planets could serve to stabilize rather than eject one another, as had originally been suggested. That means this image is the first time scientists have observed a forming planetary system, and a tightly packed one at that. [Full Story: First Image of Planet Birth Shows Tightly Packed Worlds] 

A look inside SpaceX’s astronaut taxi

SpaceX has thrown open the hatch to its Crew Dragon spacecraft, revealing a sleek black and white interior for the capsule it is building to fly astronauts to the International Space Station and other destinations. [Full Story: Step Inside Crew Dragon: SpaceX Reveals Interior of Crewed Space Capsule] 

Surprise! Mercury spinning faster than thought

New research shows that Mercury completes one rotation on its axis roughly 9 seconds more quickly than scientists previously charted — and that information will help scientists understand more about the planet’s molten core. [Full Story: Mercury’s Speedy Spin Hints at Planet’s Insides]

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

A partial solar eclipse will darken the skies above southern Africa early Sunday (Sept. 13), and the entire world can watch the spectacle live online.

This NASA graphic shows the path of visibility for the partial solar eclipse of Sept. 13, 2015. The eclipse will be visible from parts of southern Africa, as well as Antarctica.
Credit: NASA/Fred Espenak

Sunday’s eclipse will be visible to observers throughout South Africa, as well as people in the southern parts of Mozambique, Zambia, Zimbabwe and Madagascar. But wherever you are, you can view the eclipse live thanks to a free webcast hosted by the Slooh Community Observatory. The Slooh show begins at 12:30 a.m. EDT (0430 GMT) Sunday and can be viewed live on Slooh.com along with the observatory’s archive of night sky webcasts. It will run through 5 a.m. EDT (0900 GMT), with the time of maximum eclipse expected at 3 a.m. EDT (0700 GMT). 

You can also watch the solar eclipse live on Space.com, courtesy of Slooh. The webcast will feature Slooh astronomer Bob Berman and solar researcher Lucie Green. [Solar Eclipses: An Observer’s Guide (Infographic)]

The best time for Sunday’s partial solar eclipse comes at 2:54 a.m. EDT (0654 GMT), when the moon will cover 79 percent of the sun’s diameter as seen from one spot in Antarctica. But viewers in populated areas won’t see such a dramatic effect. For example, NASA eclipse expert Fred Espenak calculates that, above the South African city of Cape Town, the moon will blot out a maximum of 30 percent of the solar disk.

In Cape Town, incidentally, the eclipse will begin as the sun and moon are rising at 6:49 a.m. local time (12:49 a.m. EDT; 0449 GMT), reach its maximum extent at 7:43 a.m. local time and end at 8:49 a.m. For more information about timing in other parts of Africa, consult Espenak’s eclipse site.  

Warning: Never look directly at the sun without adequate eye protection, even during an eclipse; serious and permanent eye damage can result. You can buy special solar filters, or a No. 14 welder’s glass, which is available from welding shops. Alternatively, you can view solar eclipses indirectly by building a simple pinhole camera.

Solar eclipses occur when the Earth, moon and sun align, with the moon in the middle. When Earth’s satellite blocks out the entire solar disk, a total eclipse results; when the moon just takes out a bite, it’s a partial solar eclipse.

That total solar eclipses can occur at all is a strange accident of cosmic geometry. The sun is about 400 times wider than the moon, but it’s also 400 times farther from Earth, so the two objects are roughly the same size in Earth’s sky.

While partial solar eclipses are interesting events, total eclipses are more exciting both visually and scientifically, experts say.

“During a total solar eclipse, the moon is a near-perfect fit for the sun’s disk, so almost all of the corona is visible,” Jack Ireland, a solar physicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement.

The corona is the sun’s thin atmosphere, which is ordinarily tough to observe because it gets lost in the overwhelming glare coming from the solar surface.

A total solar eclipse will be visible to many skywatchers in the United States on Aug. 21, 2017. The “path of totality” on that day will be a band about 100 miles (160 kilometers) wide that stretches diagonally across the country from Nashville, Tennessee, to Salem, Oregon.

The August 2017 solar eclipse will mark the first time a total solar eclipse has been visible from the contiguous United States since February 1979, NASA officials said.

A total lunar eclipse will follow Sunday’s event by two weeks. On Sept. 27, the moon will pass completely into Earth’s shadow, in a spectacle visible to observers throughout North America, South America, Europe, Africa and the Middle East.

This event will occur when the full moon is closest to Earth in its elliptical path around the planet, so the occurrence has been dubbed a “supermoon total lunar eclipse.”

Editor’s note: If you capture a photo of the partially eclipsed sun or any other sky sight, you can send images and comments for possible use in a future story or gallery to managing editor Tariq Malik at: spacephotos@space.com.

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

Artist’s concept illustrating an icy planet-forming disk around the star TW Hydrae, located about 175 light-years away in the constellation Hydra. Astronomers found huge stores of cool water vapor (illustrated in blue) in the frigid outer regions of the star system, where comets will take shape. Credit: NASA/JPL-Caltech

This article was originally published on The Conversation. The publication contributed this article to Space.com‘s Expert Voices: Op-Ed & Insights.

Science fiction movies about aliens threatening the Earth routinely ascribe them the motive of coming here to steal our resources, most often our water. This is ill thought-out, as water is actually extremely common. Any civilization coming to our solar system in need of water (either to drink or to make rocket fuel) would be foolish to plunge all the way inwards to the Earth, from where they’d have to haul their booty back against the pull of the sun’s gravity.

Until recently, we believed that the Earth was the only body in the solar system that had water in liquid form. While it is true that the Earth is the only place where liquid water is stable at the surface, there’s ice almost everywhere. Many scientists also infer that liquid water may exist beneath the surfaces on several bodies.

But where in the solar system are we likely to find it and in what form? Could we ever get to it and, if so, would we be able to drink it?

Comets and the Kuiper belt

If you are interested in finding places were extraterrestrial microbial life might occur, then you should look for liquid water, or at least “warm” ice within a few degrees of melting. Those places are widespread, if you are prepared to look below the surface of cold bodies or around the edges of patches of permanent shade on hot bodies.

Frozen water can be found everywhere in the Solar System, from the Oort Cloud to Mercury (except on Venus).
Credit: NASA / JPL-Caltech

Furthest from the sun is the Oort Cloud, a region where most comets spend most of their time some 10,000 times further from the Sun than the Earth is. They are mostly water-ice, with traces of various carbon and nitrogen compounds. Because of those you wouldn’t want to drink comet water neat, but there is probably about five Earth-masses of water out there. We can’t be sure, because only the comets that stray close to the sun can be directly studied.

That’s mostly water jetting off the nucleus of comet 67P/Churyumov-Gerasimenko on 30 July 2015 as the comet drew closer to the Sun.
Credit: ESA/Rosetta/NAVCAM

Most comets are less than about 10 km across, and out in the Oort Cloud they are separated by vast distances, so if you wanted to harvest a lot of water it might be worth travelling inwards as far as the Kuiper Belt about forty times further from the sun than the Earth is.

Could Pluto hide liquid water far beneath its surface?
Credit: NASA / JPL-Caltech

Here there are bodies up to just over 2000 km in diameter, like Pluto. These are mostly water-ice surrounding rocky cores, but ices made of more volatile substances may coat their surfaces. A few may even have oceans of liquid water tens or hundreds of kilometres below their surfaces.

The giant planets

Neptune, Uranus, Saturn and Jupiter are the giants of the solar system. Deep inside, and confined by very high pressure, each of these is believed to contain several Earth-masses of water, sandwiched between its rocky core and its outer layers of hydrogen and helium gas.

Europa, a 3130 km diameter moon of Jupiter. There is almost certainly a global ocean of salty water between the surface ice and the rocky interior.
Credit: NASA/JPL-Caltech/SETI Institute

There is no feasible way to get at that water, but the giant planets each have numerous moons that are made mostly of ice. Far from the sun, the ice contains methane, ammonia and carbon monoxide as well as water. However, at the distance of Jupiter from the sun, only five times further out than the Earth, it was too hot for the more volatile ices to condense, resulting in relatively pure water ice.

There is compelling evidence that several icy moons have internal oceans. The best places to look for life are where the ocean overlies warm rock. This may be the case inside Europa (Jupiter) and Enceladus (Saturn), but chemical reactions with the rock would make the liquid water salty, so not good to drink.

The rocky planets

Closer to the sun, Mars, Earth, Venus and Mercury are in a region that was too hot for ice to condense when the solar system was forming. Consequently the planets are mostly rock, which can condense at higher temperatures than ice. The only water on the rocky planets was either trapped inside minerals and then sweated out from the interior, or was added at the surface by impacting comets.

Mars probably once had at least as much water proportional to its rock as the Earth has, but it is a smaller body with weaker gravity and no magnetic field, allowing most of its water to have been lost to space. However, water certainly flowed on Mars’s surface in the past and there are intriguing signs of water seeping downslope to form gulleys even today. However, in order to survive as a liquid this would probably have to be very salty indeed.

We know for sure that there is water-ice in the polar caps too, but neither setting seems hospitable to life. However, if you took the right kind of terrestrial microbes to the right places on Mars, they might be able to scratch a living. What we are less sure of is whether microbes have already made the trip between planets, hitch hiking on meteorites.

Whereas Mars is too cold, Venus has been too hot for liquid water for most of its history. However, there are water droplets high in its atmosphere. This is not worth collecting as a resource, and a very long shot as a means of supporting microscopic airborne life.

Mercury’s north polar region. The yellow areas are in permanent shadow.
Credit: ASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory

The last place you might expect to find water is Mercury, because it is mostly far too hot. However, there are craters near the poles onto whose floors the sun never shines. The presence of water-ice in these regions, delivered by impacting comets, has been demonstrated be several techniques and cannot be doubted.

Similarly “cold-trapped” water-ice has also been found inside polar craters on the Moon. This may be one of the first solar system resources that we, rather than visiting aliens, exploit as we leave our home world and make our way into space.

David Rothery, Professor of Planetary Geosciences, The Open University

This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives). Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google +. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com.