Wednesday, 31 December 2014

"ATTEMPT NO LANDING THERE" --New NASA Mission to Europa will Ignore Arthur C Clarke's Warning (2014 Most Popular)


NASA is ignoring Arthur C Clarke's warning to avoid exploring Juipter's moon, Europa. In 2010: Odyssey Two, a 1982 the science fiction novel by Arthur C. Clarke, the Earth mission returns to the Jupiter system to explore beneath the ice of Europa, nine years after the failure of the Discovery One mission. As Jupiter is about to transform into a new star, Lucifer, David Bowman returns to Discovery to give HAL a last order to carry out. HAL begins repeatedly broadcasting the message: ALL THESE WORLDS ARE YOURS EXCEPT EUROPA ATTEMPT NO LANDING THERE. The space agency has announced funding early development of an unusual mission to Europa as it looks toward future space exploration of planets and moons that may contain both water and extraterrestrial life.

The Europa mission proposal aims to create a gravitational map of the moon’s icy surface that many researchers suspect hides an alien ocean beneath. That map would then allow the mission’s “mothership” — a cubesat the size of several Rubik’s cubes stuck together — to deploy possibly hundreds of tiny chipsats to regions of Europa’s surface where liquid water is coming out.


The “two missions in one” concept — using cheap, expendable chipsats that represent tiny spacecraft-on-a-chip systems — could allow the mission to react quickly to new events happening on Europa’s surface, unlike more expensive missions sent to the moon and Mars in the past that just carried one large lander or robotic rover.


Based on new evidence from Europa, astronomers hypothesize that chloride salts bubble up from the icy moon’s global liquid ocean and reach the frozen surface where they are bombarded with sulfur from volcanoes on Jupiter’s innermost large moon Io. The new findings propose answers to questions that have been debated since the days of NASA’s Voyager and Galileo missions. The illustration of Europa avove (foreground), Jupiter (right) and Io (middle) is an artist’s concept.

“Let’s say we go to Europa, measure the moon’s gravity using the spacecraft’s quantum inertial sensors, and we find a cool new place with liquid water coming out of surface or near surface,” said Brett Streetman, principal investigator at the Draper Laboratory in Cambridge, Mass. “Instead of waiting for a new mission to be funded so we can bring a robotic lander the next time, now we can respond to things happening on the planet and send chipsats down right away.”

NASA’s Innovative Advanced Concepts (NIAC) Program recently awarded $100,000 to the Draper Laboratory, a not-for-profit research and development laboratory, to work out the concept for how such a mission could explore Europa and other moons or planets on the fly.

Each chipsat may only carry a few sensors capable of detecting the presence of certain chemical elements, but the lack of moving parts means the chipsats have a good chance of surviving impact upon landing on Europa’s surface.

Streetman and John West, program manager at the Draper Laboratory, have been refining the chipsat idea alongside Mason Peck, a mechanical and aerospace professor at Cornell University and former chief technologist for NASA. Draper Laboratory has also been developing a new gravitational sensor that could create a density map of Europa which would reveal the moon’s internal structure and differentiate icy or liquid parts of the moon based on their density. NASA previously used a similar gravitational sensor concept in its GRAIL mission that involved looking at the moon’s gravitational effects on the distance between twin spacecraft orbiting as a pair.

But instead of using two spacecraft, the Draper Laboratory developed cold atom sensing as a technology capable of acting as a gravitational sensor. Cold atom sensing uses a combination of magnets and laser beams to trap atoms and then measure the effect of gravity on the atom’s positions.

“We have a tabletop model working in the lab, but to my knowledge no one has deployed this technology in any field use that we know of,” West said.

This reprojection of the official USGS Europa basemap is centered at the estimated source region for potential plumes that might have been detected using the Hubble Space Telescope. The view is centered at -65 degrees latitude, 183 degrees longitude. (Credit: NASA/JPL-Caltech/SETI Institute)


Such technology could fit within a spacecraft made of several cubesats — small cubic satellites about 4 inches long on each side. The Draper Laboratory team estimates that their Europa mission mothership could range in size from three to six cubesats.

Most cubesats launch as low-cost missions that piggyback on the rocket rides of bigger missions. But the proposed Europa mission would likely need its own dedicated rocket to launch it on the proper trajectory to reach Jupiter’s moon. Still, Draper Laboratory hopes that using low-cost cubesats could make for a cheaper space mission than past planetary missions costing hundreds of millions or billions of dollars.

If Draper Laboratory can come up with a feasible mission proposal, the researchers could also apply for a second phase of NIAC funding from NASA worth about $400,000. The lab does not plan to produce spacecraft hardware during this first phase, but it does already have sample devices and prototypes for both the chipsats and the gravitational sensor.

Streetman and West chose Europa as their proposed destination because the icy moon has long intrigued researchers with the possibility of liquid water lurking beneath the frozen surface. They hope their miniaturized mission’s flexibility will speed up the process of surveying and then exploring the moon’s mysteries sometime in the next decade or two.

“Every time we go there we find cool stuff we didn’t expect to find,” Streetman said. “And we always leave with more questions than answers.”

This proposal isn’t the only idea to consider smaller robotic explorers for Europa. Another concept from NASA’s Jet Propulsion Laboratory in California and Uppsala University in Sweden suggested using a small robotic submarine the size of two soda cans to look for signs of alien life in Europa’s ocean.

Over the centuries, Europa, has provided an abundance of mysteries. These culminated in what may have been a literal explosion in December 2012, when a cloud of water vapor was seen 20 miles over its south pole. This eruption was tiny on the cosmic scale, but enormous in its importance to astrobiology.

Outside of Earth, Europa may be the most hospitable home for life inside the Solar System. Four billion years of tidal heating and a liquid ocean may have given rise to something we can identify as life. A man-made satellite in the Jovian system could potentially capture traces of that life in the water vapor shooting from Europa’s surface. Yet, in spite of the exciting science, a dedicated mission to Jupiter hasn’t launched in a generation.

Though Europa was discovered more than 400 years ago, it wasn’t until deep space satellites came along that we had our first good look at one of the most luminous objects in the Solar System. Between 1973 and 1993, eight satellites flew past Europa. Each dispelled some of the uncertainties surrounding this mysterious body orbiting 390.4 million miles (628.3 million kilometers) away.

The first arrived in 1973. The Pioneer 10 satellite sent back the first close-up photograph of that bright moon. Europa reflects back into space 64 percent of the light that falls on its surface. By contrast, Earth’s light reflectivity, or albedo, is 33 percent. Venus’ is 76 percent. In other words, Europa’s brightness falls somewhere between Earth’s liquid oceans and Venus’ constant cloud cover.

But what creates the brightness? With the Sun 2,000 times further away, Europa probably isn’t covered in liquid water the way that the Earth is. As for clouds, Europa is slightly smaller than our Moon. It lacks the gravity to maintain a substantial atmosphere. A planet coated in solid ice would explain Pioneer’s observations, but it doesn't account for one big effect: Jupiter’s tidal force. Europa’s proximity to Jupiter means that it might very well be heated from the inside out, melting some of the ice at least near the center.

Shortly before the arrival of the next satellite into the Jovian system, another suggestion was made: Europa might have three layers. In this model, the innermost core would be silica. The outermost core would be ice. The pressure of being slung around Jupiter every 3.5 days might generate enough tidal heating to maintain a liquid ocean in between. If this model were true, even though the third layer is solid, Jupiter’s tidal forces might be strong enough to crack the ice shell covering of Europa as it moves rapidly around the gas giant.

Thanks to Pioneer, Voyager and Galileo, we had learned more in three decades than in the preceding five centuries. The brightness of the ice was known to be the result of continual surface renewal. The enormous cracks, sometimes referred to as “flexi”, appear to originate when the solid ice shell flexes as Jupiter pulls on Europa. In a nod towards the three-layer-model, Galileo’s measurements also indicated that a large, salt water ocean might well exist beneath the ice shell. While all this was being discovered half a billion miles away, things were being uncovered in our own backyard that made the possibility of Europa’s oceans even more exciting.

In 1977, hydrothermal vents teeming with life were discovered deep within Earth’s oceans. This was the first proof that life could thrive in the absence of light, using heat as a source of chemical power. This led to the current understanding that life can prosper as long as there is heat and water. With a probable ocean and definite heat source, Europa suddenly became a leading candidate in the search for habitability.

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