Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Jupiter's moon Europa should be NASA's next target

20.02.2007
Jupiter's moon Europa should be NASA's next target, says ASU researcher

As NASA develops its next "flagship" mission to the outer solar system, Jupiter's enigmatic moon Europa should be the target, says Arizona State University professor Ronald Greeley. Although Europa lies five times farther from the Sun than Earth, he notes it may offer a home for life.

Greeley, a Regents' Professor, heads the Planetary Geology Group in ASU's School of Earth and Space Exploration. He is presenting the Europa proposal today (Feb. 18) at the annual meeting of the American Association for the Advancement of Science in San Francisco.

"Europa is unique in our solar system," says Greeley. "It's a rocky object a little smaller than our Moon, and it's covered with a layer of water 100 miles deep." This holds more water than all the oceans on Earth, he explains. Greeley adds that Europa also has the two other basic ingredients of life -- organic chemistry and a source of energy.

Scientists have identified four candidate worlds beyond Earth that might contain life, either now or in the past, Greeley says. These four are Mars, Saturn's moons Titan and Enceladus, and Jupiter's moon Europa.

Mars is the target of numerous ongoing missions, and NASA's Cassini spacecraft is studying both Titan and Enceladus at present. Cassini's results, however, show that Titan and Enceladus have temperatures hundreds of degrees Fahrenheit below zero and may not hold any liquid water.

NASA's Galileo mission surveyed Europa in the late 1990s. Greeley notes the mission found that Europa's surface ice was mixed with organic minerals that came up from the solid rocky part of the moon or were deposited by meteorite and comet impacts at the surface. Yet Galileo's results raised more questions than answers.

"We know Europa's surface is frozen," Greeley says. "But we don't know if it's frozen all the way down, or if there's an ocean under an ice shell."

The ice thickness is a key question, notes Greeley.

"Ultimately, we want to get down through that ice shell and into the ocean where any action is," he says. "So it matters whether the ice is 10 yards thick, or 10 miles or more. The data we have today will never answer that question."

Europa's place in the Jovian system, however, provides a possible means of measuring the ice shell's thickness. As Europa circles Jupiter every 3.6 days, it orbits in lockstep with two other moons, Ganymede and Callisto. The gravity of these bodies, plus Jupiter itself, raises tides in Europa that heat it by friction.

"Geophysical models show that if the ice goes all the way down, the amount of tidal flexing will be small, only a few feet or so," Greeley explains. "But if the ice shell is thin, say 30 feet thick, the tidal flexing could range 130 feet." What's needed, Greeley adds, is an instrument that can measure the flexing on a continuing basis.

To do that, he says, requires the spacecraft to orbit Europa while it measures the surface with a high-precision altimeter. It might be possible, Greeley notes, to measure the flexing from orbit around Ganymede, the next moon out from Europa. A Ganymede orbit would ease the task for spacecraft and instrument designers, he says, "because the radiation environment at Europa's orbit is extremely harsh." Calculations show radiation levels are high enough to damage instruments in a few months.

Mission details still need to be developed, Greeley notes, along with basic specifications for instruments and performance. He is working with Robert Pappalardo, an ASU graduate now at the Jet Propulsion Laboratory, to define more carefully the Europa orbiter mission. They expect to finish their work by the end of this summer.

The U.S. National Academy of Sciences published a report in 2003 summarizing what planetary scientists felt were the highest priority missions for the decade ahead. A Europa geophysical mission stood at the top of the list.

"In the minds of many researchers," says Greeley, "Europa is of primary importance."

Skip Derra | EurekAlert!
Further information:
http://www.asu.edu
http://www.asu.edu/news/forthemedia/20070214_Europa.htm

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>