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Nasa Moon rocket core leaves for testing – BBC News

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The first core stage for Nasa’s “mega-rocket”, the SLS, has left its factory in New Orleans for crucial tests to assess its readiness for launch.

The Space Launch System (SLS) is a critical part of the space agency’s Artemis programme, which aims to return Americans to the Moon by 2024.

The core stage is the centrepiece of the new rocket and will undergo comprehensive testing in Mississippi.

On Wednesday, it was placed on a barge which will sail it to its destination.

The rocket, which will be taller than a 30-storey building, is being built for Nasa by Boeing.

Nasa deputy administrator Jim Morhard attended the roll-out of the rocket stage from the Michoud Assembly Facility (Maf) in New Orleans where it was built.

He said it represented “an exciting leap forward in the Artemis program as Nasa teams make progress toward the launch pad”.

The rocket programme, which was announced in 2010, has been hit by delays and cost overruns.

Some in the space community believe it would be better to launch deep space missions on commercial rockets. But supporters of the programme say that Nasa needs its own heavy-lift launch capability.

After roll-out from the Maf, the core was loaded on to Nasa’s Pegasus barge to travel by water to the Stennis Space Center near Bay St Louis in Mississippi.

The test campaign at Stennis is called the “Green Run”, and will involve operating all the core stage systems simultaneously for the first time.

This will see the four powerful RS-25 engines fired for about eight minutes (or perhaps a little less), and throttled at different settings. This will mimic the levels of thrust needed during launch.

The SLS core stage contains two propellant tanks – one to hold liquid oxygen and another for liquid hydrogen. Together, they hold a combined 733,000 gallons (2.7 million litres) of propellant to power the engines.

The SLS was designed to re-use technology originally developed for the space shuttle programme, which ran from 1981-2011.

The RS-25 thrusters are the same ones that powered the orbiter, and the SLS core stage is based on the external tank that fed the shuttle engines with propellant (albeit with significant modifications).

Two solid rocket boosters (SRBs) – similar to those that helped launch the shuttle – will sit either side of the SLS core.

The rocket will provide the power required to send the Orion spacecraft – Nasa’s next-generation crew vehicle – on its way to the Moon. The rocket’s maiden launch (Artemis-1) is expected to occur some time in 2021.

Last year, John Shannon, who has been Boeing’s head of the SLS programme since 2015, told me: “I suspect that once SLS is in the national capability, there won’t be a need for another heavy-lift vehicle like it for many years. So this is really a once-in-a-generation opportunity.”

The core is the largest stage Nasa has ever had built at the Louisiana factory, including the Saturn V rocket stages for the Apollo programme.

“This is a historic moment for Nasa’s Artemis programme and a proud time for the… team as the first flight article leaves the factory floor,” said Julie Bassler, the Nasa SLS Stages manager.

Meanwhile, Nasa and its partners have completed production of the Orion spacecraft for the first Artemis mission. It is currently undergoing final testing at the Plum Brook Station in Ohio.

For the Artemis-1 mission, Orion will be sent on a loop around the Moon to test the hardware in deep space. The spacecraft will carry no crew.

The first mission to carry crew will be Artemis-2, which should send four astronauts on a lunar flyby.

Artemis-3, which is being targeted for 2024, will see a man and a woman land at the lunar south pole – the first time astronauts will have travelled to the lunar surface since 1972.

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Australian Yarrabubba meteor crater is 2.229 billion years old – SlashGear

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Scientists say that the Earth has about 190 major meteor craters on its surface. Despite having so many impact craters, scientists only know the age of a few of them. A team of scientists recently studied the Yarrabubba meteor crater in Australia and were able to determine that the crater was 2.229 billion years old.

That makes it the oldest crater currently known. It took the crown of the oldest crater from the Vredefort Dome crater in South Africa with scientists saying the Australian crater is 200 million years older. Scientists are studying crater and trying to date them in an attempt to see what sort of role they played in the environmental development of the planet.

Scientists are trying to determine how a meteor impact might relate to the formation of the continents. Science also wants to know when meteor impacts declined to the point where life could emerge. The Australian crater the team studied is in a very remote part of Western Australia and is believed to have been 70km across. It’s so old that it doesn’t look much like an impact crater.

It’s major features have been weathered away by wind, rain, and other forces leaving only overgrown rocky outcrops according to the team. The weathered remains prevented scientists from dating it with the most common form of crater dating using what’s called a “melt sheet.”

The team instead searched for rocks that could be used to date the events. The specific type of rock has the minerals zircon and monazite inside that contain uranium and lead. The ratio of those can be used to determine the age of the rock. Crystals melted by the impact were used to date the crater.

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Study reveals unexpected rise in potent greenhouse gas – Space Daily

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Scientists had expected the levels of HFC-23, a type of hydrofluorocarbon and a potent greenhouse gas, to drop in the latest global survey of greenhouse gas emissions. Instead, atmospheric concentrations of HFC-23 are rising.

HFC-23 is the byproduct of the production of HCFC-22, another hydrofluorocarbon that is commonly used in cooling systems in developing economies. India and China are two of the largest emitters of HFC-23, but in 2015, the two nations promised to rapidly reduce their HFC-23 emissions.

After making the pledge, officials in China and India reported tremendous progress with their HFC-23 abatement program, with the expectation that HFC-23 emissions would drop to nearly zero by 2017.

A new study, published Tuesday in the journal Nature Communications, suggests the opposite has happened.

Authors of the new study assumed China and India’s reported progress was real, and would lead to reduced concentration of HFC-23 in the atmosphere.

“We had no particular reason to distrust the reports. We were motivated to write the paper because the reported reductions were so dramatic,” study co-author Matthew Rigby, an atmospheric chemist at the University of Bristol in Britain, told UPI in an email. “Based on the reported values, we were expecting to see global atmospheric concentrations stabilize, following decades of growth. So it was a surprise to see them continue to grow, and in fact, grow at a faster rate than ever before.”

Rigby is a member of the Advanced Global Atmospheric Gases Experiment, UGAGE, which measure greenhouse gas concentrations in the atmosphere at test sites around the globe.

The latest findings revealed a significant global rise in HFC-23 in 2017, but the data doesn’t pinpoint the exact source of the increase. Rigby and his colleagues acknowledged that their study doesn’t prove China and India failed to execute their HFC-23 abatement programs.

“From our analysis, we cannot definitively say that China and India have not achieved their reported emission reductions,” lead study author Kieran Stanley, a post-doctoral researcher at the Goethe University Frankfurt in Germany, told UPI. “However, seeing as China and India account for 75 percent of the total global HCFC-22 production in 2017, it is highly likely that China’s reported emissions reductions haven’t taken place.”

Because India’s HCFC-22 production accounts for just 7 percent of global production, it’s harder to guess how much progress the country has made in its efforts to reduce HFC-23 emissions.

According to Stanley, had China and India truly made the emissions reduction progress they reported, that would mean large amounts of illegal, unreported HCFC-22 were manufactured in 2017. If that had happened, Stanley said the hydrocarbon’s price should have dropped. It didn’t.

After the ozone-eating gases, chlorofluorocarbons, or CFCs, were banned by the Montreal Protocol, most industries adopted a variety of alternative gases — hydrofluorocarbons. While most of theses gases are less harmful to the ozone layer, some feature a greenhouse gas effect.

In 2016, parties to the Montreal Protocol signed the Kigali Amendment, aiming to reduce the warming impact of HFCs.

HFC-23’s greenhouse gas effect is particularly potent. Just 1 metric ton of HFC-23 is equivalent to the greenhouse gas effect of 12,000 metric tons of carbon dioxide.

This isn’t the first time scientists have found concentrations of a gas regulated by the Montreal Protocol and its amendments. In 2018, scientists found evidence of a dramatic rise in the ozone-eating gas CFC-11. Investigations revealed China’s foam industry as the primary driver of the emissions increase.

“These two findings do suggest that monitoring of the chemical industry may need to be improved in China,” Rigby said. “In light of the finding of new emissions of CFC-11 from China, the government has announced additional monitoring initiatives focused on ozone depleting substances. Hopefully, they will also be able to look into these continuing emissions of the greenhouse gas, HFC-23.”

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TECH SPACE
Scientists film chemical bond making, breaking

Washington DC (UPI) Jan 17, 2020

Everything depends on chemical bonds. Without chemical bonds, everything would fall apart. And yet, scientists don’t entirely understand how chemical bonding works.
Now, for the first time, scientists have filmed chemical bond making and breaking in action. The breakthrough – described this week in the journal Science Advances – promises to offer scientists new insights into this fundamental atomic phenomenon.
The main reason chemical bonding isn’t well understood is that the processes … read more


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Earth's oldest asteroid impact 'may have ended ice age' – BBC News

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Scientists have identified the world’s oldest asteroid crater in Australia, adding it may explain how the planet was lifted from an ice age.

The asteroid hit Yarrabubba in Western Australia about 2.2 billion years ago – making the crater about half the age of Earth, researchers say.

Their conclusion was reached by testing minerals found in rocks at the site.

The scientists say the find is exciting because it could account for a warming event during that era.

The Curtin University research was published in the journal Nature Communications on Wednesday.

How did they date it?

The crater was discovered in the dry outback in 1979, but geologists had not previously tested how old it was.

Due to billions of years of erosion, the crater is not visible to the eye. Scientists mapped scars in the area’s magnetic field to determine its 70km (43 miles) diameter.

“The landscape is actually very flat because it’s so old, but the rocks there are distinctive,” researcher Prof Chris Kirkland told the BBC.

To determine when the asteroid hit Earth, the team examined tiny zircon and monazite crystals in the rocks. They were “shocked” in the strike and now can be read like “tree rings”, Prof Kirkland said.

These crystals hold tiny amounts of uranium. Because uranium decays into lead at a consistent pace, the researchers were able to calculate how much time had passed.

It is at least 200 million years older than the next most ancient impact structure – the Vredefort Dome in South Africa.

“We were interested in the area because the Western Australian landscape is very old but we didn’t expected [the crater] to be as old as this,” Prof Kirkland said.

“It’s absolutely possible that there’s an older crater out there just waiting to be discovered, but the difficulty is in finding the crust before it erodes and you lose that early Earth history”.

Could it have ended an ice age?

The timing of the impact could also explain why the world warmed around this time, according to the researchers.

Scientists believe the planet was previously in one of its “Snowball Earth” periods, when it was largely covered in ice. At some point, the ice sheets melted and the planet began to rapidly warm.

“The age of the [crater] corresponds pretty precisely with the end of a potential global glacial period,” Prof Kirkland said.

“So the impact may have had significant changes to our planetary climate.”

Using computer modelling, the team calculated that the asteroid struck a kilometres-thick ice sheet covering the Earth. The event would have released huge volumes of water vapour, a greenhouse gas, into the atmosphere.

This could have helped the planet’s warming during the Proterozoic era – a stage when oxygen had just appeared in the atmosphere and complex life had not yet formed.

“Obviously we were very excited just with the age itself,” Prof Kirkland said. “But placing that right with the context of Earth’s other events makes it become really very interesting.”

There is not enough modelling from the time to comprehensively test the theory, but “the rocks tell a story about the massive impact into the planet”.

Another theory for the warming event is that volcanic eruptions may have pushed carbon dioxide into the atmosphere.

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