NASA's new mission to estimate impact of asteroids on Earth

NASA plans to launch a new mission in 2016 to find potentially hazardous asteroids and predict their impact threat to Earth.

NASA's OSIRIS-REx asteroid sample return mission will arrive at RQ36 in 2018 and orbit the asteroid until 2021. By communicating continuously with a spacecraft in orbit around RQ36, the team will get a much better idea of the asteroid's orbit.

"We expect OSIRIS-REx will enable us to make an estimate of the Yarkovsky force on RQ36 at least twice as precise as what's available now," says Jason Dworkin, OSIRIS-REx project scientist at NASA's Goddard Space Flight Center in Greenbelt.

The Yarkovsky effect happens simply because it takes time for things to heat up and cool down. Objects tend to be coldest just before dawn and warmest at mid-afternoon, after hours of illumination by the high Sun.

The team will use what it learns about the Yarkovsky effect on RQ36 to help estimate the effects on other asteroids, NASA said in a statement.

The key to all these strategies is to discover the asteroid well in advance of its impact date and attempt to deflect it early, according to Edward Beshore of the University of Arizona, Tucson, deputy principal investigator for OSIRIS-REx asteroid sample return mission.

One of the first things that would be done if an asteroid appeared to be on a collision course with Earth is to send a probe to the asteroid that might look very much like OSIRIS-REx, said Beshore.

OSIRIS-REx will determine if RQ36 is actually a rubble pile by orbiting it and revealing the subtle effects on the orbit from the gravity of any large and dense lumps within the asteroid.

A probe like OSIRIS-REx could map the internal structure of an asteroid this way, providing valuable information on where to target the deflection mechanism.

OSIRIS-REx will also determine the composition of RQ36 using remote measurements from both visible light and infrared spectrometers, and by collecting a sample of material from the asteroid's surface and returning it to Earth for study.

Since the Yarkovsky effect may vary depending on the type of material and its distribution, a probe with OSIRIS-REx's capability to map the surface composition will enable a more precise estimate of the effect on the asteroid's orbit.

The mission will also provide critical experience navigating around asteroids.

According to NASA's Near-Earth Object (NEO) programme, there are more than 1,300 "Potentially Hazardous Asteroids" (PHAs) ¿ objects at least 150 yards across with a very small chance of impacting us someday because their orbital paths take them close to Earth's orbit.

Source:http://www.indianexpress.com/news/nasas-new-mission-to-estimate-impact-of-asteroids-on-earth/1071471/0

ESA plans to build 3D printed Moon base

The European Space Agency (ESA) plans to set up a base on Moon by using a 3D printer to build it from lunar materials, scientists say.

Industrial partners including renowned architects Foster + Partners have joined with ESA to test the feasibility of 3D printing using lunar soil, the space agency said.

“Terrestrial 3D printing technology has produced entire structures. Our industrial team investigated if it could similarly be employed to build a lunar habitat,” said Laurent Pambaguian, who heads the project for ESA.

Foster + Partners devised a weight-bearing “catenary” dome design with a cellular structured wall to shield against micro-meteoroids and space radiation, incorporating a pressurised inflatable to shelter astronauts. A hollow closed-cell structure – reminiscent of bird bones – provides a good combination of strength and weight. The base’s design was guided in turn by the properties of 3D-printed lunar soil, with a 1.5 tonne building block produced as a demonstration.

“3D printing offers a potential means of facilitating lunar settlement with reduced logistics from Earth,” added Scott Hovland of ESA’s human spaceflight team.

“The new possibilities this work opens up can then be considered by international space agencies as part of the current development of a common exploration strategy.

“As a practice, we are used to designing for extreme climates on Earth and exploiting the environmental benefits of using local, sustainable materials,” said Xavier De Kestelier of Foster + Partners Specialist Modelling Group.

“Our lunar habitation follows a similar logic,” he said in a ESA Statement.

The UK’s Monolite supplied the D-Shape printer, with a mobile printing array of nozzles on a 6 m frame to spray a binding solution onto a sand-like building material.

3D “printouts” are built up layer by layer ¿ the company more typically uses its printer to create sculptures and is working on artificial coral reefs to help preserve beaches from energetic sea waves.

“First, we needed to mix the simulated lunar material with magnesium oxide. This turns it into “paper” we can print with,” said Monolite founder Enrico Dini.

“Then for our structural ‘ink’ we apply a binding salt which converts material to a stone-like solid.

“Our current printer builds at a rate of around 2 m per hour, while our next-generation design should attain 3.5 m per hour, completing an entire building in a week,” said Dini.

Source: http://www.indianexpress.com/news/esa-plans-to-build-3d-printed-moon-base/1067991/0

US satellite lost in failed launch from Pacific

Sea Launch AG says a US communications satellite was lost after a booster rocket carrying it into space failed shortly after its launch from a floating platform in the Pacific.

The company said in a statement today the Intelsat 27 satellite was lost 40 seconds after the launch due to the failure of the Zenit-3SL rocket. The Boeing. Co-built spacecraft was launched yesterday from the Odyssey ocean platform.

Sea Launch AG President Kjell Karlsen said the cause of the failure is unknown and the company is working to evaluate it.

An affiliate of Russia’s RKK Energia state-controlled rocket manufacturer owns 95 per cent of stock in Sea Launch,

with the remainder being held indirectly by Boeing Co. and Norwegian Aker ASA. The Zenit booster is manufactured by Ukraine’s Yuzhmash rocket plant.

Source: http://www.indianexpress.com/news/us-satellite-lost-in-failed-launch-from-pacific/1067974/

‘Ozone thinning has changed ocean circulation’

A hole in the Antarctic ozone layer has changed the way waters in the southern oceans mix, which scientists say could impact global climate change.

The situation has the potential to alter the amount of CO2 in the atmosphere, scientist say.

In a study, published in the journal Science, Darryn W Waugh and his team show that subtropical intermediate waters in the southern oceans have become “younger” as the upwelling, circumpolar waters have gotten “older” – changes that are consistent with the fact that surface winds have strengthened as the ozone layer has thinned.

“This may sound entirely academic, but believe me, it’s not,” said Waugh, of the Morton K Blaustein Department of Earth and Planetary Sciences at Johns Hopkins’ Krieger School of Arts and Sciences.

“This matters because the southern oceans play an important role in the uptake of heat and carbon dioxide, so any changes in southern ocean circulation have the potential to change the global climate,” Waugh said in a statement.

Researchers used measurements taken from the early 1990s to the mid-to-late 2000s of the amount of a chemical compound known as “chlorofluorocarbon-12,” or CFC-12, in the southern oceans.

CFC-12 was first produced commercially in the 1930s and its concentration in the atmosphere increased rapidly until the 1990s when it was phased out by the Montreal Protocol on substances that deplete the ozone layer.

Researchers were able to infer changes in how rapidly surface waters have mixed into the depths of the southern oceans.

Because they knew that concentrations of CFCs at the ocean surface increased in tandem with those in the atmosphere, they were able to surmise that the higher the concentration of CFC-12 deeper in the ocean, the more recently those waters were at the surface.

The inferred age changes – “younger” in the subtropics, “older” nearer the South Pole – are consistent with the observed intensification of surface westerly winds, which have occurred primarily because of the Antarctic ozone hole, suggesting that stratospheric ozone depletion is the primary cause of the changes in ocean ventilation.

Source: http://www.indianexpress.com/news/ozone-thinning-has-changed-ocean-circulation/1067962/0

Water flow on Mars suggests ancient life on planet

Narrow ridges found in Martian craters may actually be fossilised remnants of underground cracks through which water once flowed on the red planet, a new study claims.

Water flowing beneath the surface of ancient Mars suggests life may once have been possible on the Red planet, according to a new analysis by researchers from Brown University.

The study, published in the journal Geophysical Research Letters, bolsters the idea that the subsurface environment on Mars once had an active hydrology and could be a good place to search for evidence of past life.

The study conducted by Lee Saper and Jack Mustard suggest the ridges, many of them hundreds of meters in length and a few meters wide, had been noted in previous research, but how they had formed was not known.

Saper and Mustard thought they might once have been faults and fractures that formed underground when impact events rattled the planet's crust.

Water, if present in the subsurface, would have circulated through the cracks, slowly filling them in with mineral deposits, which would have been harder than the surrounding rocks. As those surrounding rocks eroded away over millions of years, the seams of mineral-hardened material would remain in place, forming the ridges seen today.

Using high-resolution images from NASA's Mars Reconnaissance Orbiter, the researchers noted the orientations of the ridges and composition of the surrounding rocks.

The orientation data is consistent with the idea that the ridges started out as fractures formed by impact events.

Importantly, researchers also found that the ridges exist exclusively in areas where the surrounding rock is rich in iron-magnesium clay, a mineral considered to be a telltale sign that water had once been present in the rocks.

"The association with these hydrated materials suggests there was a water source available. That water would have flowed along the path of least resistance, which in this case would have been these fracture conduits," Saper said.

As that water flowed, dissolved minerals would have been slowly deposited in the conduits, in much the same way mineral deposits can build up and eventually clog drain pipes.

The results suggest the ancient Martian subsurface had flowing water and may have been a habitable environment.

"This gives us a point of observation to say there was enough fracturing and fluid flow in the crust to sustain at least a regionally viable subsurface hydrology," Saper said.

Source: http://www.indianexpress.com/news/water-flow-on-mars-suggests-ancient-life-on-planet/1066850/0

NASA launches communication satellite

NASA today launched a new communication satellite to stay in touch with its space station astronauts and relay more Hubble telescope images.

An unmanned Atlas V rocket blasted into the starry night sky carrying the Tracking and Data Relay Satellite.

This is the 11th TDRS satellite to be launched by NASA. The space agency uses the orbiting network to communicate with astronauts living on the International Space Station.

The first TDRS spacecraft flew in 1983; it recently was retired along with No. 4. The second was lost aboard space shuttle Challenger in 1986; Monday marked the 27th anniversary of the launch disaster.

This newest third-generation TDRS carries the letter K designation. Once it begins working, it will become TDRS-11. It will take two weeks for the satellite to reach its intended 22,300-mile-high orbit. Testing will last a few months.

NASA estimates the satellite costs between USD 350 million and USD 400 million. Another TDRS spacecraft, L in the series, will be launched next year.

NASA wants at least seven TDRS satellites working in orbit at any one time. The one launched today will make eight.

Source: http://www.indianexpress.com/news/nasa-launches-communication-satellite/1067256/