Jupiter showers its moon Europa with enough radiation to kill a human in just a few days. Europa must also contend with the massive planet’s powerful tidal forces. The moon literally creaks as Jupiter’s bulk rends its frozen surface in deep crevasses, pushing and pulling the ice upward and downward by tens of meters every few days. And with only a very tenuous atmosphere, it is so very cold: -210 degrees Celsius.
Yet as forbidding as Europa’s surface may be, just a few kilometers
below lies the largest ocean in the known Universe. It dwarfs any on
Earth, encircling the entire moon and plunging as far as 100 kilometers
deep. The tidal forces that wrench Europa's icy surface also tug on the
core of this ocean, dissipating heat and providing ample energy to warm
Outside of Earth, many astrobiologists say Europa’s vast, dark ocean
probably offers the best hope for finding life elsewhere in the Solar
System. For these scientists, Europa beckons like the sirens of a
NASA is very publicly planning a mission to Europa in the 2020s, one
that will soar over the intriguing moon dozens of times. Yet the reality
is more thrilling. Quietly, the same engineers who masterminded the
daring Curiosity landing on Mars in 2012 have been plotting how best to
drop a lander onto the nightmare glacier. In early November, they
presented their preliminary findings for a 230-kg lander to the one
person in the world who can, and who dearly wants to, make that happen.
“I told them to do whatever it takes,” said Representative John
Culberson after meeting with the NASA scientists. “All of humanity is
going to want to know what’s under the ice.”
A God-fearing, cowboy-boot wearing conservative Texas Republican,
Culberson is far from a household name. But as chairman of the House
Appropriations Subcommittee with oversight of NASA’s budget, he has the
final say on the agency’s budget in the House. As much as anything else
he has ever wanted in his life, Culberson yearns for NASA to land on
Europa. And with the federal purse in hand, he’s doing everything
possible to make it happen.
Culberson isn’t the first to fall under the moon’s spell. In Greek
mythology, Zeus, the Greek counterpart to the Roman god Jupiter,
abducted the Phoenician princess Europa and made her the queen of Crete.
The moon is named after her. In the seminal science fiction series Space Odyssey, novelist Arthur C. Clarke recognized Europa’s special place in the Solar System. At the end of the series’ second novel, 2010: Odyssey Two,
a ship sent to Jupiter appears to receive a message from aliens: “All
these worlds are yours except Europa. Attempt no landing there.”
Sorry HAL, we’re going. It’s difficult to imagine a more compelling
mission for NASA in the next 10 to 15 years than the exploration of
Europa. NASA touts its human “Journey to Mars,” but in reality the most
astronauts will accomplish by the mid-2020s is a repeat of the Apollo 8
flight around the Moon, which already happened in 1968. Likewise, while
Curiosity awed the world, it was the eighth probe NASA has successfully landed on Mars. Cold, dry, and probably lifeless today, Mars no longer seems all that exotic.
Europa, by contrast, is undiscovered country. NASA last visited the
Jupiter system in the 1990s and early 2000s with the Galileo spacecraft.
Galileo snapped images of Europa during 11 flybys, but everything about
those photos ended up limited. The best of those pictures had a
resolution of only about 10 meters per pixel. The spacecraft stored
those images on a tape recorder with a capacity of 114 megabytes, but a
flawed rewind mode hampered even that modest device. Additionally,
Galileo’s closest approach to Europa brought the probe only to within
about 200 km of the moon’s surface.
Despite all of this, Europa dazzled, and Galileo confirmed that a large
ocean must exist beneath the moon’s icy shell. The spacecraft’s
tantalizing findings left scientists grasping for more. During the most
recent “decadal survey” published in 2011, a document in which the
scientific community sets priorities for planetary explanation, a
mission to return a sample Martian soil and a Europa orbiter were rated
as the two highest priorities.
In the wake of the decadal survey, NASA administrator Charles Bolden was
asked about the possibility of a Europa mission during Congressional
hearings. All he would say is that he couldn’t do it. The agency, he
said, had enough on its plate. And it's true, NASA does have a lot to
do, and its budget has a lot of mouths to feed.
Culberson, at the time not yet the chairman but still a member of the
subcommittee, kept asking about Europa. If NASA could spend more than
$100 million annually on education, could it not at least begin spending
a few tens of millions of dollars to study a mission to the most
intriguing ocean in the Solar System? NASA was reluctant to take on a
new program that would ultimately cost billions, however.
Eventually Culberson stopped asking. As a member of the House
Appropriations Committee, he did what such members can do—he
appropriated. For the 2013 budget, he added $43 million to NASA’s budget
expressly for a Europa mission. Bolden didn’t want the money. So in
2014 Culberson gave him more, $80 million, directing NASA to work on
Europa. Finally, in its fiscal year 2015 budget request, NASA acquiesced
and created a Europa program. The president’s budget called for $15
million to begin preliminary studies. Culberson appropriated $100
million.Hey a new way to get money!!!!
It’s not clear why NASA ultimately embraced the Europa mission. Bolden,
appointed by a Democratic president, and Culberson, a staunch Republican
who regularly derides Obama, don’t have a good relationship. Perhaps
for NASA, Europa simply became irresistible after another key discovery
in late 2013.
That’s when NASA announced that the Hubble Space Telescope’s
spectrograph had observed a faint aurora near the moon’s south pole.
This aurora, astronomers concluded, was very likely caused by excited
oxygen and hydrogen atoms that Jupiter’s magnetic field had broken
How did that water get there? The obvious explanation was plumes of
water venting into space from Europa’s oceans. Intriguingly, active jets
were only observed when the moon was farthest from Jupiter in its
slightly eccentric, 3.5-day orbit. The researchers suspected that
Jupiter’s tidal forces would wrench the vents open at the furthest point
and then constrict the gaps closer in to the planet. For NASA, the
presence of plumes proved a game changer.
“When we had Galileo at Jupiter we didn’t look for plumes because we
didn’t know they were there,” Jim Green, a space physicist who oversees
NASA’s Planetary Sciences division, said in an interview. “They were
probably all over the place, and we probably missed opportunities all
over the place. We were just too ignorant to recognize the
Plumes of water vapor on Europa?Possible!!!!
Shortly after the Galileo probe’s demise in 2003, NASA’s next major
mission to the outer planets (the Cassini spacecraft) arrived in the
Saturn system. It carried a much more modern scientific payload, and
soon the probe found evidence of geysers on Enceladus, which rise
hundreds of kilometers into space because of the tiny moon’s slight
gravity. As Cassini flew through the plumes right over the vents, it
observed they were active along their entire length.
Such cracks on Europa might offer a window to the oceans below, and
Green seems as eager to peer into them as Culberson does. “This
mission,” he said enthusiastically, “is only getting better.”
Officially, Green says NASA hasn’t decided whether the Europa spacecraft
will carry a more expensive lander or some kind of suicide flyer that
will detach from the main vehicle, descend into an active crevasse, and
take data all the way down before being swallowed up by the moon’s icy
maw. A final decision should be made some time in 2016.
The man who could afford to pay for a more pricey lander has,
unofficially, already decided. After three years of tucking money into
NASA’s budget to pay for Europa studies, Culberson traveled to the hilly
Southern California campus of NASA's Jet Propulsion Laboratory (JPL) in
May of this year to see how those funds were being spent.
During two days of meetings hosted by Charles Elachi, the Lebanese-born
director of the laboratory, Culberson heard about the various programs
being undertaken at the storied facility. Founded by rocket scientists,
JPL has led or partially sponsored nearly every major robotic probe in
NASA’s history from America’s first satellite, Explorer 1, through the
Voyager probes, to Galileo, Cassini, and all of the Martian landers. And
although he nodded attentively during briefings on a number of topics,
what Culberson really wanted to hear about was progress being made on
the Europa mission, called a Clipper, because it will swoop into the
harsh radiation environment of Europa periodically before flying out to
more benign space to preserve its lifetime.
Eventually Elachi and his engineers came to the Clipper. During a
two-hour meeting, several engineers walked Culberson through the various
options a Europa spacecraft could employ to better understand the
nightmare glacier. The Clipper, for example, might deploy cubesats to
dip down near the planet and perhaps sample any plumes emanating from
its crevasses. It could drop a short-lived impactor or missile-like
penetrator that would strike the icy world at about 700km/h. It might
also deliver a 100 kg “rough lander” to strike the surface at about
35km/h and retain the capability to do some basic science.
Finally—but this would be expensive, the scientists warned, perhaps
adding as much as $1 billion to the mission’s cost—they discussed a
“soft lander” that would touch down at less than 5km/h. This lander
could bring a much more sophisticated scientific payload to the moon’s
surface, and it would offer the best chance of finding life.
For Culberson, it was an easy decision. Do the soft lander, he said. Why
traverse half of the Solar System if you’re not going to look for life?
He would find the money. He told the engineers to get to work on adding
a soft lander to the Clipper.
A couple of weeks later, at the end of May, NASA announced that it had
selected nine scientific instruments for its Europa mission. According
to the space agency’s news release, the solar-powered spacecraft would
launch in the 2020s and, after reaching the Jupiter system, fall into a
long, looping orbit around the gas giant. During a three-year period, it
would perform 45 flybys at altitudes ranging from 25 kilometers to
2,700 kilometers. The release made no mention of a lander, but it did
note the president’s budget for fiscal year 2016 had requested $30
million to continue developing the mission.
Meanwhile Culberson, energized after his discussions with JPL engineers,
went back to work in Washington DC. Elachi and the other lander experts
had told Culberson they would need more than $100 million during the
coming year to rapidly develop the lander concept in time to make the
Europa mission. Eventually, the House passed a budget for the 2016
fiscal year that included $140 million specifically for Europa.
Although the budget process stalled in the summer and fall months,
Congress and the White House recently struck a deal for the next two
budget years that allows for modest increases in discretionary spending,
including NASA’s budget. When that appropriation finally gets approved
later this year, will the $140 million for the Europa program be there?
During the first weekend in November, instead of returning to his home
in west Houston or attending a fundraiser, Culberson went back to JPL.
He’d given the engineers six months, and he was curious to learn about
their progress, however clandestine, with development of a lander.
Whenever he visits JPL, Culberson feels almost at home, even though many
of the scientists and engineers at the lab do not share his politics,
which veer toward the hard right wing of the political spectrum. Both
the Heritage Foundation and American Conservative Union rank him
comfortably above most Republicans in the House on their conservative
scorecards. But Culberson is as much defined by his politics as a
curiosity about the natural world. With science, he finds common cause
with the JPL engineers.
Culberson grew up in Houston, just down the road from Rice Stadium where
John F. Kennedy gave his famous “We choose to go to the Moon” speech in
1962. He was six years old at the time. Later he and his brother would
shoot off model rockets from Rice Stadium and pretend to be astronauts
in their backyard. The family vacationed in Florida twice to see Apollo
Politics ultimately called, and he ended up taking a Congressional seat
that covers much of the affluent western suburbs of Houston. His
district doesn’t include Johnson Space Center, but as a member of the
House Appropriations Committee, its leaders there look to him for
support. Yet they sometimes grumble that the Houston House member seems
more interested in JPL than his hometown space center.
During the November 2014 midterm elections, Culberson won his eighth
term in Congress, and, finally, seniority brought him to a cherished
chairmanship—not of the entire Appropriations Committee, but the
Commerce, Justice and Science Subcommittee that oversees NASA’s budget.
This gave him immense power to set priorities for the space agency.
Instead of trying to deliver pork for Johnson Space Center, he’s
continued to show more interest in planetary science.
These interests have brought him allies, including the decidedly
left-leaning Bill Nye, chief executive of The Planetary Society, a
nonprofit organization that promotes the exploration of space. The
organization has no qualms about working with Culberson, said Casey
Dreier, the Society’s director of advocacy. In fact, the society is
thrilled to have found an able champion in Congress for planetary
First, the bad news. Adding a lander to the Clipper will require
additional technical work and necessitate a launch delay until late
2023. At that time, the massive Space Launch System rocket NASA is
developing could deliver it to Jupiter in 4.6 years. Once there, the
lander would separate from the Clipper, parking in a low-radiation
The Clipper would then proceed to reconnoiter Europa, diving into the
harsh radiation environment to observe the moon and then zipping back
out into cleaner space to relay its data back to Earth. Over a
three-year period, the Clipper would image 95 percent of the world at
about 50 meters per pixel and three percent at a very high resolution of
0.5 meters per pixel. With this data, scientists could find a suitable
The JPL engineers have concluded the best way to deliver the lander to
Europa’s jagged surface is by way of a sky crane mechanism, like the one
successfully used in the last stage of Curiosity’s descent to the
surface of Mars. With four steerable engines and an autonomous system to
avoid hazards, the lander would be lowered to the moon’s surface by an
Although the SLS rocket has been designed to lift as much as 70 tons
into low-Earth orbit, it can only propel a small fraction of that across
the 800 million kilometers of space to Jupiter, and fuel and the
Clipper will consume most of that mass. The engineers have calculated
they can spare a total of about 510 kg for the sky crane and lander, and
of the 230 kg lander, about 20 to 30 kg can be given over to scientific
instruments. That may seem slight, but it’s equivalent to what the
Spirit and Opportunity rovers had to work with on Mars.
That payload would contain a mass spectrometer to identify any complex
biological molecules. The engineers are also trying to add a second type
of spectrometer, based on Raman scattering, to provide independent
confirmation of any significant findings. “Honestly,” Culberson said,
“if you’re going to go all that way to determine if there’s life on
another world, why wouldn’t you double-check it?”
To gather samples for the spectrometers, the lander will have a scooper
and sampling arm with at least one set of counter-rotating saw blades
that could penetrate to a depth of about 10 cm. At Europa’s low surface
temperatures, its ice is harder than steel.
To get the lander safe to the surface of Europa ,they will used the sky
crane like one they used to land the last mars rover!It just take some
Scientists will attempt to find this hardware a landing site near an
active crevasse. If the Hubble telescope data is correct, this would
offer a potential opening to the ocean far below. Ideally, if the lander
can be placed near a vent, it might sample spouts from the ocean below.
The engineers are also working through the feasibility of more exotic
options, such as bots that might detach from the lander and examine the
On Europa’s harsh surface, the battery-powered lander would have about a
10-day lifespan, although solar cells might extend that further. But
with dim sunlight and continual radiation, the lander’s functional time
would necessarily be short.
Unless they used RTGs! But this would add weight to the lander.
Finally, the JPL engineers are working on a “plume probe,” not as part
of the lander but which would detach from the Clipper and fly close to
the moon’s surface, perhaps 2 km or lower, to obtain samples and relay
that data back to the Clipper.
If all this sounds fantastical, well, consider the source. The engineers
and planetary scientists at JPL have a motto, Dare Mighty Things. The
very idea of landing on a creaking ice world nearly 1 billion kilometers
from Earth seems absurd. But there is a place in America where such
missions are considered and discussed with all due gravity. It’s in a
conference room at JPL known as “Left Field,” precisely because that’s
where crazy ideas come out of.
As to what the lander might ultimately discover, it is impossible to
say. That is the joy of science, delving into the unknown. The New
Horizons probe recently found unexpected wonders such as active geology
and ice volcanoes on Pluto, at the cold edge of the Solar System.
Imagine why lies in wait at Europa, a far more dynamic world capable of
One of the scientists in attendance at the November briefings with
Culberson was the physicist and five-time astronaut John Grunsfeld. He
was enthusiastic, Culberson recalled. “Grunsfeld said several times
during the briefing that if this mission is like others we’ve flown to
other mysterious worlds, Europa will prove far more interesting than we
can ever imagine.”
Grunsfeld is NASA’s associate administrator for the Science Mission
Directorate, which means he oversees all of the agency’s scientific
activities, including planetary science. His presence at those meetings
and enthusiasm for the mission signifies the space agency has finally
bought fully into Europa. And why wouldn’t it, Culberson mused. “I
cannot think of anything that would energize the public more than the
discovery of life on another world,” he said. “It would inspire the
public to support NASA even further.”
There are very few guarantees when it comes to spaceflight, and
especially so with NASA’s budget. The agency is bedeviled by a
year-to-year budgetary subsistence that makes long-term planning a
continuous waltz of uncertainty. But consider this: the US House is
solidly in Republican hands, and Culberson probably has more than five
years left in his post as subcommittee chairman. That gets the Europa
mission through 2020, to within three years of launch, by which point
NASA and the scientific community will be heavily invested in the
Over in the Senate, he has allies, too. Key Republican and Democratic
senators support development of the Space Launch System, which is so
expensive to build and fly that NASA’s human exploration program can’t
afford to build payloads for crewed missions. The big rocket needs
meaningful launches, and getting the Clipper to Jupiter fast would fit
snugly into its launch manifest. Even if the SLS rocket never flies,
private companies such as SpaceX and United Launch Alliance are building
smaller, but still capable, heavy-lift rockets that could get a lander
to Europa, albeit over a longer period of time.
Now that NASA has the will, a way can be found. And so humans will wake
the nightmare glacier, knowing not what secrets sleep within.
As you can tell there is far more water on these moon than the Earth.