Rendering showing the location and size of water vapor plumes coming from Europa's south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne
It was about this time last year that Europa really began to excite us again. Following a sci-fi movie about the Jupiter moon, astronomers using the Hubble Space Telescope announced they had found possible water vapor near the icy moon — maybe from geysers erupting from its icy surface. (That is, if the finding was not due to signal noise, which researchers acknowledged at the time.)
As NASA ramped up (distant) plans to get close to Europa again, scientists began plumbing data from the Cassini spacecraft to see if its glance at the moon circa 2001 revealed anything. Turns out that the spacecraft didn’t see any sign of a plume. Which leads to the greater question, what is happening?
Now scientists are scurrying for a second look. Hubble is in the midst of a six-month search of the moon (from afar) to see if any more of the plumes are showing up. Now the theory is that the plumes, if they do exist, would be intermittent — at least, that’s according to the team looking at data from Cassini’s ultraviolet imaging spectograph (UVIS).
Europa (bottom left) in orbit around its planet, Jupiter, as spotted from the Cassini spacecraft in 2000. Credit: NASA/JPL/University of Arizona
“It is certainly still possible that plume activity occurs, but that it is infrequent or the plumes are smaller than we see at Enceladus,” stated co-author Amanda Hendrix, a Cassini UVIS team member with the Planetary Science Institute in Pasadena. “If eruptive activity was occurring at the time of Cassini’s flyby, it was at a level too low to be detectable by UVIS.”
This finding was part of a greater set of observations showing that it’s not really Europa that is contributing plasma (superheated gas) to space — it’s the ultra-volcanic moon Io. And Europa itself is sending out 40 times less oxygen than previously believed to the area surrounding the moon.
“A downward revision in the amount of oxygen Europa pumps into the environment around Jupiter would make it less likely that the moon is regularly venting plumes of water vapor high into orbit, especially at the time the data was acquired,” NASA stated. This would stand in contrast to, say, Saturn’s Enceladus — which Cassini has seen sending plumes high above the moon’s surface.
The findings were presented at the American Geophysical Union meeting earlier this month and also published in the Astrophysical Journal. The research was led by Don Shemansky, a Cassini UVIS team member with Space Environment Technologies.
Now in its seventh year of compilation and the second year running on Universe Today, we’re proud to feature our list of astronomical happenings for the coming year. Print it, bookmark it, hang it on your fridge or observatory wall. Not only is this the yearly article that we jokingly refer to as the “blog post it takes us six months to write,” but we like to think of it as unique, a mix of the mandatory, the predictable and the bizarre. It’s not a 10 ten listicle, and not a full-fledged almanac, but something in between.
A rundown of astronomy for 2015: There’s lots of astronomical action to look forward to in the coming year. 2015 features the minimum number of eclipses that can occur, two lunars and two solars. The Moon also reaches its minimum standstill this coming year, as its orbit runs shallow relative to the celestial equator. The Moon will also occult all naked eye planets except Saturn in 2015, and will occult the bright star Aldebaran 13 times — once during every lunation in 2015. And speaking of Saturn, the rings of the distant planet are tilted an average of 24 degrees and opening to our line of sight in 2015 as they head towards their widest in 2018.
Finally, solar activity is trending downwards in 2015 after passing the sputtering 2014 maximum for solar cycle #24 as we now head towards a solar minimum around 2020.
Our best bets: Don’t miss these fine celestial spectacles coming to a sky near YOU next year:
– The two final total lunar eclipses in the ongoing tetrad, one on April 4th and September 28th.
– The only total solar eclipse of 2015 on March 20th, crossing the high Arctic.
– A fine dusk pairing of the bright planets Jupiter and Venus on July 1st.
– Possible wildcard outbursts from the Alpha Monocerotid and Taurid meteors, and a favorable New Moon near the peak of the August Perseids.
– Possible naked eye appearances by comet Q2 Lovejoy opening 2015 and comet US10 Catalina later in the year.
– The occultation of a naked eye star for Miami by an asteroid on September 3rd.
– A series of fine occultations by the Moon of bright star Aldebaran worldwide.
The rules: The comprehensive list that follows has been lovingly distilled down to the top 101 astronomical events for 2015 worldwide. Some, such as lunar eclipses, are visible to a wide swath of humanity, while others, such as many of the asteroid occultations or the sole total solar eclipse of 2015 happen over remote locales. We whittled the list down to a “Top 101” using the following criterion:
Meteor showers: Must have a predicted ZHR greater than 10.
Conjunctions: Must be closer than one degree.
Asteroid occultations: Must have a probability ranking better than 90 and occult a star brighter than magnitude +8.
Comets: Must reach a predicted brightness greater than magnitude +10. But remember: comets don’t always read prognostications such as this, and may over or under perform at whim… and the next big one could come by at any time!
Times quoted are geocentric unless otherwise noted, and are quoted in Universal Time in a 24- hour clock format.
These events are meant to merely whet the appetite. Expect ‘em to be expounded on fully by Universe Today as they approach. We linked to the events listed where possible, and provided a handy list of resources that we routinely consult at the end of the article.
Got it? Good… then without further fanfare, here’s the top 101 astronomical events for 2015 in chronological order:
The path of Comet Q2 Lovejoy from January 1st to January 31st. Created using Starry Night Education software.
29- The Moon occults Aldebaran at ~17:31 UT for the Arctic, marking the first of 13 occultations of the star by the Moon in 2015.
The view at 6:40 UT on January 24th, as 3 of Jupiter’s moons cast shadows on to the Jovian cloud tops simultaneously. Created using Starry Night Education software.
February
01- Venus passes 0.8 degrees south of Neptune at ~17:00 UT.
05- Earth crosses through Jupiter’s equatorial plane, marking the middle of occultation and eclipse season for the Galilean moons.
06- Jupiter reaches opposition at ~18:00 UT.
18- A “Black Moon” occurs, in the sense of the third New Moon in a season with four.
22- Venus passes 0.4 degrees south of Mars at 5:00 UT.
24- Mercury reaches greatest morning elongation at 26.7 degrees west of the Sun at 19:00 UT.
21- Io and Ganymede both cast shadows on Jupiter from 00:04 to 00:33 UT.
21- Callisto and Europa both cast shadows on Jupiter from 13:26 to 13:59 UT.
23- Saturn reaches opposition at ~1:00 UT.
24- Asteroid 1669 Dagmar occults the +1st magnitude star Regulus at ~16:47 UT for the Arabian peninsula,
the brightest star occulted by an asteroid for 2015.
28- Ganymede and Io both cast shadows on Jupiter from 02:01 to 04:18 UT.
30- Comet 19P/Borrelly may reach binocular visibility.
June
01- The International Space Station reaches full illumination as the June solstice nears, resulting in multiple nightly passes favoring northern hemisphere observers.
04- Io and Ganymede both cast shadows on Jupiter from 4:54 to 6:13 UT.
05- Venus reaches greatest eastern (dusk) elongation for 2015, 45 degrees from the Sun at 16:00 UT.
10- Asteroid 424 Gratia occults a +6.1 magnitude star at ~15:10 UT for northwestern Australia.
13- The Perseid meteors peak from 06:30 to 09:00 UT, with a maximum predicted ZHR of 100 favoring North America.
19- Mars crosses the Beehive Cluster M44.
28- Asteroid 16 Psyche occults a +6.4 magnitude star at ~9:49 UT for Bolivia and Peru.
29- Supermoon 1 of 3 for 2015: The Moon reaches Full at 18:38 UT, 20 hours from perigee.
The path of the Moon through the Earth’s shadow on September 28th. Credit: Fred Espenak/NASA/GSFC
September
01- Neptune reaches opposition at ~3:00 UT.
03- Asteroid 112 Iphigenia occults a +3rd magnitude star for Mexico and Miami at ~9:20 UT. This is the brightest star occulted by an asteroid in 2015 for North America.
02- Geostationary satellite and SDO eclipse season begins as we approach the September equinox.
04- Mercury reaches its greatest elongation for 2015, at 27 degrees east of the Sun at 8:00 UT in the dusk skies.
05- The Moon occults Aldebaran for northeastern North America at ~5:38 UT.
13- “Shallow point” (also known as the minor lunar standstill) occurs over the next lunation, as the Moon’s orbit reaches a shallow minimum of 18.1 degrees inclination with respect to the celestial equator… the path of the Moon now begins to widen towards 2025.
13- A partial solar eclipse occurs, centered on 6:55 UT crossing Africa and the Indian Ocean.
25- Mars passes 0.8 degrees from Regulus at ~4:00 UT.
28- A total lunar eclipse occurs centered on 2:48 UT, visible from the Pacific, the Americas and eastern Europe.
28- Supermoon 2 of 3 for 2015: The Moon reaches Full at 2:52 UT, approximately an hour from perigee. This marks the closest Full Moon of the year.
The path of the September 3rd occultation of a +3rd magnitude star by an asteroid over central Mexico and the Florida Keys. Credit: IOTA/Steve Preston.
The Moon occults Aldebaran: the visibility footprint for North America. The dashed line denotes the area in which the event occurs during the daytime. Credit: Occult 4.1.0.11.
November
01- Io and Ganymede both cast shadows on Jupiter from 17:36 to 17:47 UT.
02- Venus passes 0.7 degrees south of Mars at 00:30 UT.
12- Will the 7 year “Taurid fireball meteor shower” produce?
18- The Leonid meteor shower peaks at 04:00 UT, with an estimated ZHR of 15 favoring Europe.
22- Are we in for a once per decade Alpha Monocerotids outburst? The 2015 peak arrives at 4:25 UT, favoring Europe… with a max ZHR = 400+ possible.
The daytime occultation of Venus by the Moon over North America on December 7th.Credit: Occult 4.1.0.11.
December
01- The International Space Station reaches full illumination as the December solstice nears, resulting in multiple nightly passes favoring the southern hemisphere.
04- Mercury occults the +3.3 magnitude star Theta Ophiuchi for South Africa at 16:16 UT prior to dusk.
06- The Moon occults Mars for central Africa at ~2:42 UT.
07- The Moon occults Venus in the daytime for North America at ~16:55 UT.
14- The Geminid meteor shower peaks at 18:00 UT, with a ZHR=120 favoring NE Asia.
This is a type of shrimp that lives in hydrothermal vents (areas of hot water) in the Caribbean. NASA is studying Rimicaris hybisae and other "extreme shrimp" to learn more about lifeforms that could survive on other worlds. Credit: Chris German, WHOI/NSF, NASA/ROV Jason C: 2012 Woods
For all of the talk about aliens that we see in science fiction, the reality is in our Solar System, any extraterrestrial life is likely to be microbial. The lucky thing for us is there are an abundance of places that we can search for them — not least Europa, an icy moon of Jupiter believed to harbor a global ocean and that NASA wants to visit fairly soon. What lurks in those waters?
To gain a better understanding of the extremes of life, scientists regularly look at bacteria and other lifeforms here on Earth that can make their living in hazardous spots. One recent line of research involves shrimp that live in almost the same area as bacteria that survive in vents of up to 750 degrees Fahrenheit (400 degrees Celsius) — way beyond the boiling point, but still hospitable to life.
Far from sunlight, the bacteria receive their energy from chemical combinations (specifically, hydrogen sulfide). While the shrimp certainly don’t live in these hostile areas, they perch just at the edge — about an inch away. The shrimp feed on the bacteria, which in turn feed on the hydrogen sulfide (which is toxic to larger organisms if there is enough of it.) Oh, and by the way, some of the shrimps are likely cannibals!
One species called Rimicaris hybisae, according to the evidence, likely feeds on each other. This happens in areas where the bacteria are not as abundant and the organisms need to find some food to survive. To be sure, nobody saw the shrimps munching on each other, but scientists did find small crustaceans inside them — and there are few other types of crustaceans in the area.
But how likely, really, are these organisms on Europa? Bacteria might be plausible, but something larger and more complicated? The researchers say this all depends on how much energy the ecosystems have to offer. And in order to see up close, we’d have to get underwater somehow and do some exploring.
In a recent Universe Today interview with Mike Brown, a professor of planetary science at the California Institute of Technology, the renowned dwarf-planet hunter talked about how a submarine could do some neat work.
“In the proposed missions that I’ve heard, and in the only one that seems semi-viable, you land on the surface with basically a big nuclear pile, and you melt your way down through the ice and eventually you get down into the water,” he said. “Then you set your robotic submarine free and it goes around and swims with the big Europa whales.” You can see the rest of that interview here.
The puzzling, fascinating surface of Jupiter’s icy moon Europa looms large in this newly-reprocessed color view, made from images taken by NASA’s Galileo spacecraft in the late 1990s. Image credit: NASA/JPL-Caltech/SETI Institute
A montage of images taken of Jupiter and its moon Io (foreground) by the New Horizons mission in 2007. Jupiter is shown in infrared wavelengths while Io is close to true-color. On top of Io is an eruption from the volcano Tvashtar. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
New Horizons, you gotta wake up this weekend. There’s so much work ahead of you when you reach Pluto next year! The spacecraft has been sleeping quietly for weeks in its last great hibernation before the dwarf planet close encounter in July. On Saturday (Dec. 6), the NASA craft will open its eyes and begin preparations for that flyby.
How cool will those closeups of Pluto and its moons look? A hint comes from a swing New Horizons took by Jupiter in 2007 en route. It caught a huge volcanic plume erupting off of the moon Io, picked up new details in Jupiter’s atmosphere and gave scientists a close-up of a mysterious “Little Red Spot.” Get a taste of the fun seven years ago in the gallery below.
An eruption from the Tvashtar volcano on Io, Jupiter’s moon, in several different wavelength images taken by the New Horizons spacecraft in 2007. The left image from the Long Range Reconnaissance Imager (LORRI) shows lava glowing in the night. At top right, the Multispectral Visible Imaging Camera (MVIC) spotted sulfur and sulfor dioxide deposits on the sunny side of Io. The remaining image from the Linear Etalon Imaging Spectral Array (LEISA) shows volcanic hotspots on Io’s surface. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstituteJupiter’s “Little Red Spot” seen by the New Horizons spacecraft in 2007. The spot turned red in 2005 for reasons scientists were then unsure of, but speculated it could be due to stuff from inside the atmosphere being stirred up by a storm surge. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstituteA “family portrait” of the four Galilean satellites around Jupiter taken by the New Horizons spacecraft and released in 2007. From left, the montage includes Io, Europa, Ganymede and Callisto. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstituteA composite of Jupiter’s bands (and atmospheric structures) taken in several images by the New Horizons Multispectral Visual Imaging Camera, showing differences due to sunlight and wind. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstituteIn February and March 2007, a huge plume erupted from the Tvashtar volcano on Jupiter’s moon Io. The image sequence taken by New Horizons showed the largest such explosion then viewed by a spacecraft — even accounting for the Galileo spacecraft that examined Io between 1996 and 2001. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstituteThe New Horizons flyby of Io in 2007 (right) revealed a changing feature on the surface of the Jupiter moon since Galileo’s image of 1999 (left.) Inside the circle, a new volcanic eruption spewed material; other pictures showed this region was still active. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Artist's impression of the Jupiter Icy Moons Explorer (JUICE) near Jupiter and one of its moons, Europa. Credit: ESA/AOES
It takes years of painstaking work to get a spacecraft off the ground. So when you have a spacecraft like JUICE (the Jupiter Icy Moons Explorer) set to launch in 2022, you need to back up about a decade to get things figured out. How will the spacecraft get there? What science instruments will it carry? What will the spacecraft look like and what systems will support its work?
JUICE just hit another milestone in its development a few days ago, when the European Space Agency gave the go-ahead for the “implementation phase” — the part where the spacecraft design begins to take shape. The major goal of the mission will be to better understand those moons around Jupiter that could be host to life.
The spacecraft will reach Jupiter’s system in 2030 and begin with observations of the mighty planet — the biggest in our Solar System — to learn more about the gas giant’s atmosphere, faint rings and magnetic environment. It also will be responsible for teaching us more about Europa (an icy world that could host a global ocean) and Callisto (a moon pockmarked with the most craters of anything in the Solar System.)
Its major departure from past missions, though, will come when JUICE enters orbit around Ganymede. This will the first time any spacecraft has circled an icy moon repeatedly; past views of the moon have only come through flybys by the passing-through spacecraft (such as Pioneer and Voyager) and the Galileo mission, which stuck around Jupiter’s system in the 1990s and early 2000s.
Ganymede Credit: NASA
With Ganymede, another moon thought to host a global ocean, JUICE will examine its surface and insides. What makes the moon unique in our neighborhood is its ability to create its own magnetic field, which creates interesting effects when it interacts with Jupiter’s intense magnetic environment.
“Jupiter’s diverse Galilean moons – volcanic Io, icy Europa and rock-ice Ganymede and Callisto – make the Jovian system a miniature Solar System in its own right,” the European Space Agency stated when the mission was selected in 2012.
“With Europa, Ganymede and Callisto all thought to host internal oceans, the mission will study the moons as potential habitats for life, addressing two key themes of cosmic vision: what are the conditions for planet formation and the emergence of life, and how does the Solar System work?”
Europa. CThe cracked, icy surface of Europa. The smoothness of the surface has led many scientists to conclude that oceans exist beneath it. Credit: NASA/JPLredit: NASA
Europa, Jupiter’s sixth-closest moon, has long been a source of fascination and wonder for astronomers. Not only is it unique amongst its Jovian peers for having a smooth, ice-covered surface, but it is believed that warm, ocean waters exist beneath that crust – which also makes it a strong candidate for extra-terrestrial life.
And now, combining a mosaic of color images with modern image processing techniques, NASA has produced a new version of what is perhaps the best view of Europa yet. And it is quite simply the closest approximation to what the human eye would see, and the next best thing to seeing it up close.
The high-resolution color image, which shows the largest portion of the moon’s surface, was made from images taken by NASA’s Galileo probe. Using the Solid-State Imaging (SSI) experiment, the craft captured these images during it’s first and fourteenth orbit through the Jupiter system, in 1995 and 1998 respectively.
The view was previously released as a mosaic with lower resolution and strongly enhanced color (as seen on the JPL’s website). To create this new version, the images were assembled into a realistic color view of the surface that approximates how Europa would appear to the human eye.
This newly-reprocessed color view of Europa was made from images taken by NASA’s Galileo spacecraft in the late 1990s. Image credit: NASA/JPL-Caltech/SETI Institute
As shown above, the new image shows the stunning diversity of Europa’s surface geology. Long, linear cracks and ridges crisscross the surface, interrupted by regions of disrupted terrain where the surface ice crust has been broken up and re-frozen into new patterns.
Images taken through near-infrared, green, and violet filters have been combined to produce this view. The images have been corrected for light scattered outside of the image to provide a color correction that is calibrated by wavelength. Gaps in the images have been filled with simulated color based on the color of nearby surface areas with similar terrain types.
These color variations across the surface are associated with differences in geologic feature type and location. For example, areas that appear blue or white contain relatively pure water ice, while reddish and brownish areas include non-ice components in higher concentrations.
The polar regions, visible at the left and right of this view, are noticeably bluer than the more equatorial latitudes, which look more white. This color variation is thought to be due to differences in ice grain size in the two locations.
Artist’s concept of the Galileo space probe passing through the Jupiter system. Credit: NASA
This view of Europa stands out as the color view that shows the largest portion of the moon’s surface at the highest resolution. An earlier, lower-resolution version of the view, published in 2001, featured colors that had been strongly enhanced. Space imaging enthusiasts have produced their own versions of the view using the publicly available data, but NASA has not previously issued its own rendition using near-natural color.
The image also features many long, curving, and linear fractures in the moon’s bright ice shell. Scientists are eager to learn if the reddish-brown fractures, and other markings spattered across the surface, contain clues about the geological history of Europa and the chemistry of the global ocean that is thought to exist beneath the ice.
This is of particular interest to scientists since this supposed ocean is the most promising place in our Solar System, beyond Earth, to look for present-day environments that are suitable for life. The Galileo mission found strong evidence that a subsurface ocean of salty water is in contact with a rocky seafloor. The cycling of material between the ocean and ice shell could potentially provide sources of chemical energy that could sustain simple life forms.
Future missions to Europa, which could involve anything from landers to space penetrators, may finally answer the question of whether or not life exists beyond our small, blue planet. Picturing this world in all of its icy glory is another small step along that path.
In addition to the newly processed image, JPL has released a new video that explains why this likely ocean world is a high priority for future exploration:
Artist's conception of CubeSats near Europa (left) and Jupiter. Credit: NASA/JPL
When you’ve got a $2 billion mission concept to head to Europa, it’s likely a good idea to pack as much science on this mission as possible. That’s the thinking that NASA had as it invited 10 universities to send their ideas for CubeSats — tiny satellites — that would accompany the Europa Clipper mission to the Jupiter system.
Europa Clipper is only on the drawing board right now and not fully funded, and should not be confused with the lower-cost $1 billion Europa mission that NASA proposed earlier this year (also not fully funded). But however NASA gets there, the agency is hoping to learn if the moon could be a good spot for life.
Each university is being awarded up to $25,000 to develop their ideas further, and they will have until next summer to work on them. Investigations include searching the surface for future landing sites, or examining Europan properties such as gravity, its atmosphere, magnetic fields or radiation.
Two reddish spots (Thera and Thrace) stick out on this image of Europa taken by the Galileo orbit in the 1990s. NASA says they display “enigmatic terrain.” Credit: NASA/JPL/University of Arizona
“Using CubeSats for planetary exploration is just now becoming possible, so we want to explore how a future mission to Europa might take advantage of them,” said Barry Goldstein, pre-project manager for the Europa Clipper mission concept, in a press release.
If Europa Clipper flies, it would do at least 45 flybys at altitudes between 16 miles and 1,700 miles (25 kilometers and 2,700 kilometers.) Part of its expense comes from the long distance, and also from all the radiation shielding the spacecraft would need as it orbits immense Jupiter.
Science instruments are still being figured out, but some ideas include radar (to look under Europa’s crust), an infrared spectrometer (to see what is on the ice), a camera to image the surface and a spectrometer to look at the moon’s thin atmosphere.
While there are no Europa missions officially booked now, NASA does have an active spacecraft called Juno that will arrive at Jupiter in July 2016.
Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC
TORONTO, CANADA – Could NASA’s new rocket bring a probe to sample the geysers of Saturn’s moon Enceladus, or ferry human explorers to the surface of Mars? Representatives of contractor Boeing think so.
They’ve put together some ideas for sending their Space Launch System to these far-flung destinations, which they presented at the International Astronautical Congress today (Oct. 1).
Bear in mind that the SLS hasn’t yet flown — it’s slated for 2018 if funding lasts and the schedule holds — and the destinations below are just in the conceptual stage. The gallery below summarizes some of the destinations SLS could visit. For more information, check out this brochure by Boeing.
Enceladus
Artist’s conception of the Cassini spacecraft flying amid geysers on Enceladus, a moon of Saturn. Credit: Karl Kofoed / NASA
The icy moon of Saturn is known as a hotspot for geysers; earlier this year, scientists found 101 gushers using data from the prolific Cassini probe. Using the SLS could bring a satellite there in four years, as opposed to about seven with rockets on the market today, according to Boeing. It also could carry a heavier spacecraft.
Europa
Artist’s conception of Europa’s surface, backdropped by planet Jupiter. Credit: NASA/JPL-Caltech
Europa is known to have a subterranean ocean, and it also is capable of spewing water plumes — as researchers using the Hubble Space Telescope discovered earlier this year. The SLS could get to Europa a lot faster than a launch with an Atlas, according to Boeing — it would only take two years to fly there directly as opposed to more than six years with the Atlas, which would need to fly by Venus first to pick up some speed.
Trojan asteroids
Artist’s diagram of Jupiter and some Trojan asteroids nearby the gas giant. Credit: NASA/JPL-Caltech
Trailing before and after Jupiter are more than a million asteroids that are called Trojans. This means any probe in the area would have no lack of targets to study, providing it had enough fuel on board. A mission profile from Boeing suggests the SLS could bring a spacecraft out there that could swing by a target at least half a dozen times.
Mars
Artist’s impression of astronauts exploring Mars. Credit: NASA/Pat Rawlings, SAIC
One of the largest challenges of getting to Mars is figuring out how to send all the life-support equipment and food that humans require — on top of the humans themselves! Since SLS is a heavy-lift rocket, Boeing is trying to position its rocket as the ideal one to get humans to Mars. But it remains to be seen what concept works best to get people out there.
The Moon
Artist’s impression of astronauts on the moon. This image was used to illustrate a landing concept of NASA’s now defunct Constellation program. Credit: John Frassanito and Associates / NASA
Boeing has an idea to bring a lander down to the Moon that could then lift off multiple times in search of other destinations. Such a concept would require a hefty amount of fuel and equipment. If it works, Boeing says the SLS could assist with plans for lunar mining and other exploration ideas.
Reprocessed Galileo image of Europa's frozen surface by Ted Stryk (NASA/JPL/Ted Stryk)
Mysteries abound on icy Europa, that cold moon of Jupiter. Even years after the Galileo spacecraft finished its mission in the Jovian system, scientists are still trying to figure out the nature of the cracks on Europa’s surface. In an exciting find, one new paper suggests that at least part of the terrain could be due to plate tectonics.
If proven, this would be the first time that plate tectonics have been strongly suggested as a process working beyond Earth. On our home planet, scientists believe that this process, which happens as plates of Earth’s crust move, is responsible for creating mountains and volcanoes and earthquakes.
So why do they think this process is happening on Europa? The short answer is, weird terrain. For example, Scientists have seen evidence of what is called extension, which happens when the surface expands and then stuff from the layers below fills in the gap. But there were pieces of that understanding missing until now, the team says.
“We have been puzzled for years as to how all this new terrain could be formed, but we couldn’t figure out how it was accommodated,” stated Louise Prockter, a planetary scientist at Johns Hopkins University Applied Physics Laboratory who co-authored the study. “We finally think we’ve found the answer.”
An illustration of how subducting tectonic plates might work on Jupiter’s moon, Europa. This would bring the moon’s estimated 10-20 mile (20-30 kilometer) ice shell into the warmer insides of the moon. Credit: Noah Kroese, I.NK
Despite being pretty confident about the extension, scientists were unable to account for how all the new material arrived.
What the team did was try to model how Europa’s surface looked before how all the cracks appeared, and discovered that 7,700 square miles (20,000 square kilometers) couldn’t be accounted for in the high northern latitudes.
Looking more closely, they found ice volcanoes that they believe was on a surface plate, and missing mountains in what is thought to be a subduction zone. This suggests that stuff from the surface gets pushed underneath — not crushed into each other.
Rendering showing the location and size of water vapor plumes coming from Europa’s south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne
“Europa may be more Earth-like than we imagined, if it has a global plate tectonic system,” stated Simon Kattenhorn of the University of Idaho, Moscow, who led the study.
“Not only does this discovery make it one of the most geologically interesting bodies in the solar system, it also implies two-way communication between the exterior and interior — a way to move material from the surface into the ocean — a process which has significant implications for Europa’s potential as a habitable world.”
A "colorized" image of Europa from NASA's Galileo spacecraft, whose mission ended in 2003. The whiteish areas are believed to be pure water ice. Credit: NASA/JPL-Caltech/SETI Institute
What lies beneath the cracked, thick ice on the surface of Europa? NASA is hoping to fly a mission to the Jupiter moon in the coming years to see if it is indeed a promising site for life. If this concept is approved in the budget, think of the mission as a recce: NASA will either orbit the moon, or do several flybys on it, to scout the surface for science and potential landing sites.
NASA just announced its desire to have science instruments proposed for the mission. Of the submitted list, 20 proposals will be selected in a year’s time, when selectees will have $25 million to do a more advanced concept study.
“The possibility of life on Europa is a motivating force for scientists and engineers around the world,” stated John Grunsfeld, associate administrator for NASA’s science mission directorate. “This solicitation will select instruments which may provide a big leap in our search to answer the question: are we alone in the universe?”
The Europa mission is not a guarantee, and it’s unclear just how much money will be allocated to it in the long run. (NASA has requested $15 million in fiscal 2015 for the mission). The mission is also subject to budgetary approvals from Congress. If it passes all obstacles, it would fly sometime in the 2020s, according to information released with the budget earlier this year.
Reprocessed Galileo image of Europa’s frozen surface by Ted Stryk (NASA/JPL/Ted Stryk)
In April, NASA sent out a request for information to interested potential participants on the mission itself, which it plans to cost less than $1 billion (excluding launch costs).
“Recent NASA studies have focused on an orbiter mission concept and a multiple flyby mission concept as the most compelling and feasible,” the agency stated.
Besides its desire to look for landing sites, NASA said the instruments should also be targeted to meet the National Resource Council’s (NRC) Planetary Decadal Survey’s desires for science on Europa. In NASA’s words, these are what those objectives are:
Rendering showing the location and size of water vapor plumes coming from Europa’s south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne
Characterize the extent of the ocean and its relation to the deeper interior;
Characterize the ice shell and any subsurface water, including their heterogeneity, and the nature of surface-ice-ocean exchange;
Determine global surface, compositions and chemistry, especially as related to habitability;
Understand the formation of surface features, including sites of recent or current activity, identify and characterize candidate sites for future detailed exploration;
Understand Europa’s space environment and interaction with the magnetosphere.
Any instruments must meet NASA’s landing scout goal or the NRC goals, the agency said. The instruments also must be highly protected against the harsh radiation in the area, and also meet planetary protection requirements to ensure no extraterrestrial life is contaminated with our own.
