LARES 'mirror ball' sat will test
Einstein's theory

For similar stories, visit the Solar System , Spaceflight and Cosmology Topic Guides You don't have to be big to challenge Einstein. A pocked ball just 36 centimetres wide is the latest space probe tasked with measuring general relativity, one of the cornerstones of modern physics. The Laser Relativity Satellite, or LARES, is a tungsten sphere with reflectors mounted in 92 holes punched into its surface. It is due to launch from Kourou, French Guiana, on a new Eu ropean Space Agency rocket called Vega, designed to cheaply launch payloads of less than 2500 kilograms. The launch window opens on 13 February. LARES's orbit will be tracked by bouncing ground-based lasers off the reflectors. General relativity states that gravity arises from the curvature of space and time. If this is true, Earth should drag space-time around with it as it spins, slightly perturbing the orbits of satellites. Though general relativity is the accepted theory of gravity, it might break down if measured with greater accuracy. The beleaguered Gravity Probe B satellite achieved an accuracy within 19 per cent of the expected orbit change; earlier satellites got within 10 per cent. Researchers hope to achieve 1 per cent with LARES, built by the Italian Space Agency.
Expect to see more launches from the Kourou spaceport, which is ESA-owned, in future. Vega is due to launch an experimental ESA craft in 2014 to test technologies – such as a heat shield – for a possible crewed mission. Vega could also launch small astronomy and climate satellites, says Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. One of the few other small launchers, McDowell says, is the troubled Taurus rocket, built by US-based Orbital Sciences Corporation. It has had two failed launches of climate satellites in recent years – NASA's Orbiting Carbon Observatory and Glory spacecraft. Vega will help make the European spaceport in Kourou a destination for all kinds of launches, since the powerful Ariane 5 and medium-class Soyuz also launch from there. "It's rounding out European space technology," McDowell says. "They can compete across the board."

Source: newscientist.com

Tiny volcanic moon controls
Jupiter's auroras

Sometimes the puppets control the puppeteer. It seems volcanic outbursts on Jupiter's moon Io control brilliant auroras on its parent planet. Auroras are shimmering curtains of light caused when charged particles slam into a planet's magnetic field. Earth's northern and southern lights are active only when the sun releases a big blob of charged plasma, as it did on 24 January. Jupiter has a permanent ring of auroral light surrounding each of its poles (see photo). Most of the charged particles responsible for the light have long been thought to originate from tiny, hyperactive Io, which burps out about a tonne of sulphur per second in its persistent, violent volcanic activity. However, the sun was thought to cause any variations in the rings via changes in the pressure of the solar wind. New observations suggest that Io can control these changes as well. "Variations we thought were connected to the sun we now see are connected to the volcanic activity," says Bertrand Bonfond of the University of Liège in Belgium.
Mega plume Bonfond and colleagues observed Jupiter and Io with the Hubble Space Telescope once a day between February and June 2007. In those five months, the team captured twice as much data as had been collected in the previous 10 years. "Never before did we have daily observations of the auroras," Bonfond says. "[Until then] we couldn't disentangle the day-by-day variations and the global trends." Over that time, Jupiter's constant auroral rings grew significantly, but it was not clear why. The solution came when NASA's New Horizons spacecraft flew by Jupiter in May 2007 on its way to Pluto. The probe snapped spectacular images of a volcanic plume hundreds of kilometres highMovie Camera erupting out of Io's surface. The influx of plasma from this huge eruption flooded Jupiter's magnetic field, widening the auroral rings. "The auroras are really responding to this increased amount of material coming out of Io," Bonfond says.
Margaret Kivelson of the University of California, Los Angeles, says the new paper shows that Io can control Jupiter's auroras over long timescales. However, she says the sun is still a player on timescales of a day or so. "This does not rule out contributions from the solar wind," she says. Team member Denis Grodent of the University of Liège agrees. "The question is certainly still open," he says. "The role of the solar wind is unclear, because of the lack of long-term observations." There are also other mysteries to be solved, like how the charged particles are accelerated along Jupiter's magnetic field lines. For answers, Bonfond looks to the Juno spacecraft that launched last August and will reach Jupiter in 2016. "For the first time we can analyse [the magnetic interactions] on another planet than the Earth," he says. "It will be a game-changer."
Source: newscientist.com

Private spacecraft move forward as Soyuz struggles

All eyes are on commercial space companies in the wake of the latest setback for Russia's space programme, which has delayed the launch of the next crew to the International Space Station. A recent flight of a private rocket bodes well for the fledgling industry, but the coming weeks should reveal whether the industry can really take off. Russia's space agency Roscosmos reported last week that the Soyuz capsule meant to take astronauts to the station on 30 March sprang a leak when the air pressure inside it was accidentally pumped too high during a test. Another Soyuz capsule is being prepared for launch in its place but will not be ready to fly until 15 May. It's just the latest in a string of problems for Russian space vehicles. In August, for example, an uncrewed Soyuz rocket crashed to Earth. That temporarily threw the space station's future into doubt because the same type of rocket is the only craft used to launch crews to the outpost. NASA says it remains confident in Roscosmos's ability to fly astronauts, but says the problems highlight the importance of developing other means of sending crews to the station. "The Soyuz is probably one of the most reliable systems out there, but when you have a spacecraft as significant as the ISS, it makes sense to get more than one capability to get humans [there]," Mike Suffredini, NASA's space station manager, said in a teleconference last week.
NASA has previously estimated that commercial space taxis could be ready to carry astronauts in 2017. But the date will depend partly on how much money NASA can spend to help private companies develop their vehicles. NASA received $406 million for this purpose in 2012, but had asked for $850 million. The White House will tip its hand about future spending priorities when it releases its proposed 2013 budget for federal agencies, including NASA, next Monday. The companies already receiving NASA funding are also set to show their stuff. California-based SpaceX has been working towards launching a space capsule called Dragon on a mission to dock with the station. That launch will likely occur in early April, Suffredini said. That Dragon capsule will be uncrewed, but SpaceX hopes to win a contract to fly astronauts to the station on later Dragon flights.

Orbital Sciences Corporation, based in Dulles, Virginia, which has a NASA contract to fly cargo to the station on a spacecraft called Cygnus, is farther from launch. It was scheduled to fly a demonstration mission to the station in April or May but will probably be delayed, Suffredini said: "We're working on a number of options with them" for later flight dates. However another private rocket company, Armadillo Aerospace, recently made its highest flight yet, flying its uncrewed STIG-A rocket just shy of the 100-kilometre boundary of space on 28 January. The company hopes to reach space for the first time by mid-2012, and aims to develop a more powerful launcher to fly people on suborbital trips. The recent flight "tested many of the core technologies needed for the proposed manned reusable suborbital vehicle", Neil Milburn of Armadillo said in a statement.

Source: newscientist.com

Spacecraft is first to bring asteroid dust to Earth

The troubled Hayabusa space probe has become the first spacecraft to bring material from an asteroid back to Earth, the Japanese Aerospace Exploration Agency (JAXA) has announced. Although Hayabusa's capsule was retrieved earlier this year, it wasn't clear whether the dust it contained came from the asteroid it landed on in 2005. Now an analysis by JAXA has shown that the dust's composition is extra-terrestrial, even containing a mineral not found on the Earth's surface. Further study may reveal what materials existed when the solar system formed, and give insights into how best to mitigate asteroid impacts based on new knowledge of their composition. "The science that we will obtain from these particles over the next few years will be invaluable," says Paul Abell of the NASA Johnson Space Center in Houston, Texas, who is a member of the Hayabusa Joint Science Team. "After all the hard work and the many years of patiently waiting, we now can say that we have returned samples from an asteroid to the Earth for the very first time," he says.
Hayabusa blasted off in 2003 with a clear mission: to collect samples from the asteroid Itokawa. But after several technical failures and a bumpy landing on the asteroid in 2005, when it was 300 million kilometres from Earth, there were fears Hayabusa might not make it back. Despite these hitches, Hayabusa was nursed back to life and released a capsule that landed safely in the Australian outback Movie Camerain June. It was still not clear, however, whether Hayabusa had actually managed to grab dust from the asteroid. Things looked promising in July, when JAXA confirmed that the capsule contained particles, but there was a possibility that these were contaminants from Earth.
Now, after analysing some 1500 particles using scanning electron microscopes, JAXA says that nearly all the material was extraterrestrial and originated in Itokawa. The relative abundances of elements and minerals in the dust – including olivine and plagioclase – are similar to what is seen in primitive meteorites and do not correspond to the make-up of any rock found on Earth's surface, JAXA reports. What's more, one mineral in the dust, troilite (an iron sulphide), is not present on the Earth's surface. "Everything points to a successful sample return from Itokawa," says Trevor Ireland, an earth chemist at the Australian National University in Canberra, who was involved in preliminary work on the dust sample. Over the next few years, the particles will be analysed further to see what they can reveal about asteroids, meteorites and the formation of the solar system. The particles from Itokawa may have retained minerals from the early solar system, unlike meteorites whose composition may have been altered by the high pressures and temperatures they encounter as they crash to Earth.

Source: newscientist.com

Astrophile: A-List black hole gets a face

Astrophile is our weekly column on curious cosmic objects, from the solar system to the far reaches of the multiverse
Object type: Black hole
Location: M87 galaxy, 50 million light years from Earth
Being photographed is pretty much a way of life for human celebrities. Not so astronomical ones. The most massive black hole ever measured, which lies at the heart of the galaxy M87, 50 million light years from Earth, is the closest thing we have to a celestial bigwig. Yet no picture of it, or any other black hole, has ever been snapped. That's not just a problem for fans lusting after a pin-up. Seeing the shadow of a black hole would provide the first direct evidence that these bizarre objects really do exist. What's more, looking at the way light bends around the edges of the shadow could also turn up deviations from Einstein's theory of general relativity, the reigning theory of gravity that some physicists want to replace. The trouble is not that black holes are invisible: as great absorbers of light, they should appear as a black spot when viewed against a bright background. Rather, all known black holes are too far away for ordinary telescopes to make out the shadow. However, plans are afoot to take a picture of a black hole using radio telescopes set far apart on Earth but which together act like a single huge telescope thousands of kilometres acrossMovie Camera. In the meantime, Jason Dexter of the University of California in Berkeley and colleagues have created the next best thing – the most realistic preview yet of what the black hole at the heart of M87 looks like. As well as putting a face on this A-list object, their simulations reveal details that suggest glimpsing M87's black hole for real may well be feasible.
The team simulated how matter and light behave near M87's black hole. Unlike previous efforts, their calculations fully incorporated general relativity and the effects of powerful magnetic fields near the black hole. They simulated the disc of gas and dust that is swirling around it as well as the powerful jet of electrically charged particles shooting into space from the black hole's vicinity. Both the disc and jet emit radio waves. But rather than travelling in straight lines, the radio waves are bent by the black hole's powerful gravity, which acts a little bit like a lens. This would radically distort the appearance of the disc and jet in radio images, the researchers found, smearing them to make a bright crescent surrounding the dark shadow of the black hole. In a real image, the existence of this shadow would provide direct evidence for an event horizon, the defining feature of a black hole. Once light, or anything else, passes inside this boundary, it can never escape.
The simulations suggest the black hole's shadow should be observable with telescopes that researchers are planning to link up for this purpose. The researchers concluded this from calculations of the shadow's size and the size of the smallest details discernable by such linked telescopes. With a mass that was recently revised upwards to 6.4 billion times that of the sun, M87's black hole seems like an ideal photographic target, because its shadow should look relatively large in the sky. Though the black hole at the heart of our own galaxy would appear slightly larger because it is so much closer, M87's position in the sky means it is easier to observe using some of the best radio telescopes. Its black hole could well be the first to be seen directly. These images will be the next best thing to actually travelling across the event horizon into a black hole – an experience that has been simulatedMovie Camera but will remain forever in the realms of science fiction.

Source: newscientist.com