Laboratory models suggest that stretching forces shaped Ganymede's surface

An image of a tabletop-size analogue model (left) shows details of fault systems created by extension that visually match an image by spacecraft Galileo of faulted terrain on Ganymede (right). 

Credit: Left Image: Courtesy of Southwest Research Institute; 

Right Image: Courtesy of NASA/JPL SSI

Processes that shaped the ridges and troughs on the surface of Jupiter's icy moon Ganymede are likely similar to tectonic processes seen on Earth, according to a team of researchers led by Southwest Research Institute (SwRI).

To arrive at this conclusion, the team subjected physical models made of clay to stretching forces that simulate tectonic action. The results were published in Geophysical Research Letters.

Physical analogue models simulate geologic structures in laboratory settings so that the developmental sequence of various phenomena can be studied as they occur.

The team, including researchers from SwRI, Wheaton College, NASA's Jet Propulsion Laboratory and NuStar Energy LP, created complex patterns of faults in their models, similar to the ridge and trough features seen in some regions of Ganymede.

The models consisted of a "wet clay cake" material possessing brittle characteristics to simulate how the icy moon's lithosphere, the outermost solid shell, responds to stresses by cracking.

The laboratory models suggest that characteristic patterns of ridges and troughs, called grooved terrain on Ganymede, result from its surface being stretched.

"The physical models showed a marked similarity to the surface features observed on Ganymede," said co-author Dr. Danielle Wyrick, a senior research scientist in the SwRI Space Science and Engineering Division.

"From the experiments, it appears that a process in which the crust breaks into separate blocks by large amounts of extension is the primary mechanism for creating these distinct features."

"Physical analogue modeling allows us to simulate the formation of complex three-dimensional geological structures on Ganymede, without actually going to Ganymede," said co-author Dr. David Ferrill, director of the Earth, Material and Planetary Sciences Department in the SwRI Geosciences and Engineering Division.

"These scaled models are able to reproduce the fine geometric details of geologic processes, such as faulting, and to develop and test hypotheses for landscape evolution on planetary bodies."

SwRI researchers previously have used physical analog models to examine the process by which pit crater chains, a series of linear pits, or depressions, develop on Mars, and how magma in the Martian subsurface deforms the surface of the Red Planet.

More information: The paper, "Physical models of grooved terrain tectonics on Ganymede," by D.W. Sims, D.Y. Wyrick, D.A. Ferrill, A.P. Morris, G.C. Collins, R.T. Pappalardo and S.L. Colton, was published by Geophysical Research Letters, 16 June 2014, Volume 41, Issue 11, pages 3774–3778, DOI: 10.1002/2014GL060359

NASA's Orion spacecraft proves sound under pressure

After a month of being poked, prodded and pressurized in ways that mimicked the stresses of spaceflight, NASA's Orion crew module successfully passed its static loads tests on Wednesday.

When Orion launches on Exploration Flight Test-1 (EFT-1), which is targeted for September 2014, it will travel farther from Earth than any spacecraft built for humans in more than 40 years.

The spacecraft will fly about 3,600 miles above Earth's surface and return at speeds of approximately 25,000 mph.

During the test, Orion will experience an array of stresses, or loads, including launch and reentry, the vacuum of space, and several dynamic events that will jettison hardware away from the spacecraft and deploy parachutes.



To ensure Orion will be ready for its flight test next year, engineers at NASA's Kennedy Space Center in Florida built a 20-foot-tall static loads test fixture for the crew module with hydraulic cylinders that slowly push or pull on the vehicle, depending on the type of load being simulated.

The fixture produced 110 percent of the load caused by eight different types of stress Orion will experience during EFT-1.

More than 1,600 strain gauges recorded how the vehicle responded. The loads ranged from as little as 14,000 pounds to as much as 240,000 pounds.

"The static loads campaign is our best method of testing to verify what works on paper will work in space," said Charlie Lundquist, NASA's Orion crew and service module manager at the agency's Johnson Space Center in Houston. "This is how we validate our design."

In addition to the various loads it sustained, the Orion crew module also was pressurized to simulate the effect of the vacuum in space.

This simulation allowed engineers to confirm it would hold its pressurization in a vacuum and verify repairs made to superficial cracks in the vehicle's rear bulkhead caused by previous pressure testing in November.

The November test revealed insufficient margin in an area of the bulkhead that was unable to withstand the stress of pressurization.

Armed with data from that test, engineers were able to reinforce the design to ensure structural integrity and validate the fix during this week's test.

To repair the cracks, engineers designed brackets that spread the stress of being pressurized to other areas of the module that are structurally stronger.

During these tests Orion was successfully pressurized to 110 percent of what it would experience in space, demonstrating it is capable of performing as necessary during EFT-1.

Space Suits: This Year's Look is Skinny

After saying goodbye to the space shuttle program, NASA decided to ditch its big, bulky space suits for something slimmer.

The new exhibit "Beyond Planet Earth: The Future of Space Exploration" at the American Museum of Natural History in New York showcases the next generation of spacesuit made from spandex, nylon and a new patented polymer.

The exhibit opens Saturday. The BioSuit uses elastic cords running though the clothing made of nylon-spandex, elastic or urethane-painted foam to cover the entire body.

The BioSuit also relies on mechanical pressure rather than pressurized gas to protect the astronaut. The patented polymer material in the space suit replaces the compressed air of older suits.

The space-age material is more lightweight and more maneuverable than traditional spacesuits, NASA officials said.

More importantly, a small tear in the suit would only affect one area and wouldn't cause a deadly decompression accident. The helmet would be the only part of the suit that would need to be pressurised.

Researchers at the Massachusetts Institute of Technology designed the BioSuit. Dava Newman, MIT professor of aeronautics and lead of the project, said the BioSuit was designed for astronauts working in planetary environments like those of the Moon or Mars where walking will be a key requirement.

"We really must design for greater mobility and enhanced human and robotic capability," Newman said. "It's a whole different ballgame when we go to the Moon or Mars, and we have to go back to walking and running or loping."

The MIT team has already made models of the suit that provide up to 30 kilopascals of pressure but they say it will take another 10 years of testing to produce a suit that could be used on actual space missions.

Superhard, amorphous diamond created

The Tiffany Yellow Diamond

An amorphous diamond, one that lacks the crystalline structure of diamond, but is every bit as hard, has been created by a Stanford-led team of researchers.

What good is an amorphous diamond?

“Sometimes amorphous forms of a material can have advantages over crystalline forms,” said Yu Lin, a Stanford graduate student involved in the research.

The biggest drawback with using diamond for purposes other than jewelry is that even though it is the hardest material known, its crystalline structure contains planes of weakness.

Those planes are what allow diamond cutters to cleave all the facets that help give a diamond its dazzle – they are actually breaking the gem along weak planes, not cutting it.

“With diamond, the strength depends on the direction a lot. It’s not a bad property, necessarily, but it is limiting,” said Wendy Mao, the Stanford mineral physicist who led the research. “But if diamond is amorphous, it may have the same strength in all directions.”

That uniform super-hardness, combined with the light weight that is characteristic of all forms of carbon, including the diamond, could open up exciting areas of application, such as cutting tools and wear-resistant parts for all kinds of transportation.

Other researchers have tried to create diamond-like amorphous carbon, but have only been able to make extremely thin films that contain impurities such as hydrogen and do not have completely diamond-like atomic bonds.

The amorphous diamond created by Mao and Lin can be made in thicker bulk forms, opening up more potential applications.

The researchers, seen here, created the new, super-hard form of carbon using a high-pressure device called a diamond anvil cell.

They did a series of experiments with tiny spheres of glassy carbon, an amorphous form of carbon which they compressed between the two diamond anvils.

The spheres were a few tens of micrometers (millionths of a meter) in diameter.

They slowly cranked up the pressure on the spheres. When the pressure exceeded 40 gigapascals, 400,000 times atmospheric pressure, the arrangement of the bonds between the carbon atoms in the glassy spheres had completely shifted to a form that endowed the spheres with diamond-like strength.

The researchers detected the shift in internal bonding by probing the spheres with X-rays.

They also did experiments in which a glassy sphere was simultaneously subjected to different pressures from different directions, to further assess the strength of the new form of carbon.

While the diamonds in the anvil pressed in on the sides of the sphere with a pressure of 60 gigapascals, about 600,000 times atmospheric pressure, the pressure on the tip of the sphere reached 130 gigapascals.

To read more go to the Stanford Univeristy News Site

See 10 Legendary Diamonds and their stories here

SpaceX Dragon lands in Florida

A history-making space capsule has landed at Cape Canaveral's museum.

The Dragon Capsule by SpaceX -- the first commercial enterprise to launch, fly, land and recover a spacecraft from Earth orbit -- is now on display at the Air Force Space and Missile History Center.

Flown on a SpaceX rocket last December and unveiled for the first time to the public on Friday, the capsule is the forerunner to a NASA demonstration flight slated for this fall.

"Dragon, the first commercially manufactured, human-rated transport vehicle, may serve as a critical asset in the country's next-generation manned space exploration initiatives," SpaceX said in a statement.

Dragon is a free-flying, reusable spacecraft being developed by SpaceX under NASA's Commercial Orbital Transportation Services (COTS) program. Initiated internally by SpaceX in 2005, the Dragon spacecraft is made up of a pressurized capsule and unpressurised trunk used for Earth to LEO transport of pressurised cargo, unpressurized cargo, and/or crew members.

The Dragon spacecraft is comprised of 3 main elements: the Nosecone, which protects the vessel and the docking adaptor during ascent; the Spacecraft, which houses the crew and/or pressurised cargo as well as the service section containing avionics, the RCS system, parachutes, and other support infrastructure; and the Trunk, which provides for the stowage of unpressurized cargo and will support Dragon’s solar arrays and thermal radiators.

Space Exploration Technologies Corporation - Dragon

Digital Signatures - Lily pads

Digital signatures

One way of obtaining proof of identity is to use digital pads that capture people's signatures.

These pads capture not only the shape of the mark, but also the speed at which it was written and the pressure applied at different points.

Songhua Xu at Zhejiang University, China, and colleagues at the University of Hong Kong have developed a way to digest that information into a digital "lily", to allow quick but robust comparisons.

(Image: Songhua Xu)