AFTER more than a decade
in pursuit, clocking up 6.5 billion kilometres and five loops around the Sun,
the Rosetta spacecraft has closed in on its target, becoming the first in
history to go into orbit about a comet.
With a thrust of its engines, the
European spacecraft was kicked into the first leg of its triangular orbit about
the duck-shaped comet, although scientists had to wait a further 25 minutes —
the time taken for the probe’s faint signal to reach Earth — to learn that the
manoeuvre had been a success.The comet, called 67P/Churyumov-Gerasimenko, or “Chury”, lies 405 million km from Earth, between the orbits of Jupiter and Mars, and is rushing towards the inner solar system at nearly 55,000km/h.
The craft will now spiral inward towards Chury until it is less than a mile away and close enough to release a robotic lander that will float down on to the surface.
Jean-Jacques Dordain, director-general of the European Space Agency (ESA), said: “We are delighted to announce finally ‘we are here’. Europe’s Rosetta is now the first spacecraft in history to rendezvous with a comet, a major highlight in exploring our origins. The discoveries can begin.”
The mission will ultimately examine the chemical make-up of the comet in unprecedented detail and could reveal whether so-called dirty snowballs could have originally brought water and the basic building blocks of life to Earth billions of years ago.
The latest phase of the mission began in January, when the probe successfully “woke up” from a three-year period of hibernation, during which it was so far from the Sun that the little solar energy available was required to warm its internal computers. The coming months will hold further nailbiting moments for the scientists involved.
Much of the equipment aboard the lander has been in a dormant state during the 10-year journey and scientists say that it is impossible to be completely confident that each component will switch on again smoothly. These components include small harpoons that will tether the lander to the surface of the comet, to prevent it from bouncing off, and drills in its legs that will secure it firmly.
Richard Holdaway, director of Rutherford Appleton Laboratory Space, said: “It’s like an old car on a winter’s day. Most of the time it works, but occasionally it doesn’t. That’s the sort of uncertainty we’re dealing with.”
The latest close-up images hint at other challenges that will be faced, when Philae, the fridge-sized lander, is dropped on to the surface in November. The images reveal the comet is composed of two distinct segments joined by a “neck”, giving it a duck-like appearance, and it has a rugged surface littered with boulders and troughs. The next two months will be spent assessing the comet for potential landing sites.
Matt Taylor, ESA’s Rosetta project scientist, said: “Our first clear views of the comet have given us plenty to think about. Is this double-lobed structure built from two comets that came together in the solar system’s history, or is it one comet that has eroded dramatically and asymmetrically over time?”
It will not be until Philae touches down that scientists learn whether the surface is ice-hard or dusty.
“The landing is going to be pretty hairy,” Professor Holdaway said. “And the chance of missing it is finite, albeit very small.”
As the comet travels closer to the Sun, it is likely to become more active, warming up and releasing more dust and other compounds accumulated on its surface. Sensors on board Rosetta and Philae will analyse these, looking in particular for organic compounds that indicate that comets could have initially seeded Earth with the building blocks for life.
Ian Wright, professor of planetary sciences at The Open University in the UK, said: “We will be looking for evidence recorded in remnants of debris that survived the processes of planet formation. This is not merely a period of prehistory, but one that predates the origin of life itself. Our quest is to gain insights into this transitional era, which took place more than 4.5 billion years ago.”
By Hannah Devlin
With thanks to The Australian
From The Australian December 21st
AN Australian rock art study has been named one of the top 10 scientific breakthroughs of the year by the influential journal Science.
The study, published in October, revealed that hand stencils and animal paintings in a cave in the Indonesian island of Sulawesi were up to four times as old as previously thought.
“The discoveries suggest that humans in Asia were producing symbolic art as early as the first European cave painters,” said the American Association for the Advancement of Science, publisher of one of the world’s two most recognised journals.
It rated the achievement alongside pivotal studies in genetics, robotics, palaeontology and Alzheimer’s and diabetes research.
But the journal awarded top marks to the European Space Agency for landing a spacecraft on a comet.
The spacecraft Rosetta and its lander module Philae made major headlines in November when Philae touched down on the surface of the speeding comet. While the landing was rougher than expected, the data from the two space probes is already shedding new light on the formation and evolution of such comets.
“Philae’s landing was an amazing feat and got the world’s attention,” said Science news editor Tim Appenzeller. “But the whole Rosetta mission is the breakthrough. It’s giving scientists a ringside seat as a comet warms up, breathes and evolves.”
The European Space Agency's Rosetta spacecraft was launched in 2004, on a mission to meet up with a comet. It was partially powered down to save energy during the long voyage. Now, scientists can finally check in with Rosetta. Photo: ESA-C. Carreau/ATG medialab
Picture from The Australian below.
Rosetta Mission’s Probe Makes Historic Comet Landing
Landing site chosen.
Canadian firm playing big role in historic comet visit.
ROBOT probe Philae
bounced twice after its historic comet landing, probably ending up with one leg
dangling in space, in the shadow of a cliff that could prevent it fully charging
its battery, ground control says.
In the 24 hours since its
pioneering deep-space contact, the lab has sent home a slew of data and
photographs from the surface of comet 67P/Churyumov-Gerasimenko — though from a
mystery location thought to be hundreds of metres off target.Harpoons were meant to anchor Philae to the low-gravity comet 510 million kilometres from Earth and zipping towards the Sun at 18 kilometres per second.
The harpoons failed to deploy, but this has not prevented Philae sending information to Earth via its orbiting mothership, Rosetta.
“We have a better understanding of how we got there, but we still do not really know where,” lander manager Stephan Ulamec said in a press conference webcast live from European Space Agency (ESA) ground control in Darmstadt, Germany.
“We could be somewhere in the rim of this crater,” he added, pointing to a surface shot on which deep crevices lie in permanent, pitch-black shadows.
“We are not standing parallel to the surface,” said Ulamec — an evaluation gleaned from the angle of photographs Philae has sent to Rosetta to be relayed to Earth.
Eight of Philae’s 10 on-board science instruments and cameras have kicked into action as planned — a highlight achievement in the ESA’s flagship $1.95 billion project. The data from some of these washing machine-sized instruments revealed that the first bounce, “a huge leap” according to Ulamec, lasted about two hours and moved the probe a kilometre from its target site, followed by a second, smaller rebound.
There are fears that Philae may not be able to use the drill with which it was equipped to take sub-surface comet samples for chemical testing.
Mission scientist Jean-Pierre Bibring says Philae is almost vertical, with one foot probably in open space and two on the comet surface, while Philippe Gaudon of France’s CNES space agency earlier said the probe was “likely on a steep slope”.
Trying to activate the drill, or even the harpoons, without knowing the lander’s location and orientation could be dangerous. “We may just tip over our lander,” said Ulamec, adding Philae may not have enough power for a dedicated jump out of the hole in which it may sit.
The probe’s battery will only last about 60 hours, and given its awkward position, Philae is not getting enough sunlight for a full recharge, receiving only 1.5 hours per day instead of the six or seven required.
Wednesday’s elation at the landing signal from Philae after a seven-hour descent, soon turned to worry as fluctuations in the radio signal indicated the 100-kilogram lander may have lifted off again.
This was followed by a long silence until Thursday’s briefing, where ESA experts underlined the mission’s successes, including the first-ever pictures taken from the surface of a comet.
The Rosetta mission aims to unlock the secrets that comets, primordial clusters of ice and dust, are thought to hold about how the Solar System was formed about 4.6 billion years ago.
With thanks to The Australian
Rosetta Probe Philae Discovers Organic Molecules On Comet
THE probe that landed on
the surface of a comet has discovered organic molecules, the most rudimentary
building blocks of life, according to the German agency involved in the mission.
An instrument aboard the Philae
lander detected the molecules after “sniffing” the comet’s atmosphere. An
organic compound is one whose molecules contain the carbon atom, the basis of
life on earth.Scientists are analysing the data to see whether the organic compounds detected by Philae are simple ones — such as methane and methanol — or a more complex species such as amino acids, the building blocks for proteins.
A drill on Philae also obtained some material from the comet’s hard surface, but data about organic molecules from that experiment have yet to be fully analysed.
Comets contain some of the most pristine materials in the solar system, dating to about 4.5 billion years ago. Previous studies have suggested that comets forge organic material in their dusty atmospheres.
A study of the comet’s organic materials “will help us to understand whether organic molecules were brought by comets to the early earth,” which could have kickstarted life here, said Stephan Ulamec, the Philae lander manager and scientist at the German Aerospace Centre. The agency runs the lander control centre and oversaw the comet landing last Thursday.
Researchers had expected to find organic molecules on the comet, known as 67P/Churyumov-Gerasimenko. But thanks to the probe, they are for the first time able to conduct a direct search for organic molecules in both the comet’s gases and its surface material.
The data sent back by Philae, part of a European Space Agency mission. now will be checked against similar information already obtained by the orbiting Rosetta. In early August, when Rosetta was within 200km of the comet, one of its sensors was able to study the coma, or envelope of gases surrounding the comet’s nucleus.
Those early measurements detected water, carbon monoxide and carbon dioxide, which were likely to have been released from below the comet’s surface layer. It also found traces of ammonia, methane and methanol. In October, Rosetta scientists studying the coma said they had picked up traces of the organic compound formaldehyde as well as other molecules, including sulfur dioxide and hydrogen sulfide, which smells like rotten eggs.
An even bigger find would be the discovery of an amino acid on comet 67P. In 2009, a US spacecraft discovered the amino acid glycine on a comet. A similar find on 67P would bolster a view that life on earth was seeded by comets that brought organic compounds with them.
Although Philae’s primary battery ran out of power on Saturday (AEDT), scientists completed a manoeuvre that has positioned one of the probe’s larger solar panels more fully toward sunlight. It means that the probe may yet come to life next year or a bit earlier, as the comet heads closer to the sun.
“We are very confident that in coming months we’ll get more sun and power and Philae can be reactivated,” Dr Ulamec said.
From The Australian – November 18th
AN Australian rock art study has been named one of the top 10 scientific breakthroughs of the year by the influential journal Science.
The study, published in October, revealed that hand stencils and animal paintings in a cave in the Indonesian island of Sulawesi were up to four times as old as previously thought.
“The discoveries suggest that humans in Asia were producing symbolic art as early as the first European cave painters,” said the American Association for the Advancement of Science, publisher of one of the world’s two most recognised journals.
It rated the achievement alongside pivotal studies in genetics, robotics, palaeontology and Alzheimer’s and diabetes research.
But the journal awarded top marks to the European Space Agency for landing a spacecraft on a comet.
The spacecraft Rosetta and its lander module Philae made major headlines in November when Philae touched down on the surface of the speeding comet. While the landing was rougher than expected, the data from the two space probes is already shedding new light on the formation and evolution of such comets.
“Philae’s landing was an amazing feat and got the world’s attention,” said Science news editor Tim Appenzeller. “But the whole Rosetta mission is the breakthrough. It’s giving scientists a ringside seat as a comet warms up, breathes and evolves.”
From the Australian December 21st.
See also:
World’s Oldest Rock Art Found In Indonesia - Updated
Update June 15th, 2015
