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Nasa's new 'megarocket' set for critical tests – BBC News

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.css-1ecljvk-StyledFigureCopyrightposition:absolute;bottom:0;right:0;background:#3F3F42;color:#EEEEEE;padding:0.25rem 0.5rem;text-transform:uppercase;NASA

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.css-14iz86j-BoldTextfont-weight:bold;Nasa has been developing a “megarocket” to send humans to the Moon and, eventually, Mars. The last critical tests of the giant launcher’s core section are expected to take place within the next few weeks. Sometimes compared to the iconic Saturn V, can the Space Launch System (SLS) help capture the excitement of lunar exploration for a new generation?

In southern Mississippi, near the border with Louisiana, engineers have been putting a remarkable piece of hardware through its paces.

A giant orange cylinder is suspended on an equally imposing steel structure called the B-2 test stand on the grounds of Stennis Space Center, a Nasa test facility outside the city of Bay St Louis.

Measuring 65m (212ft) from top to bottom – longer than the Statue of Liberty – the cylinder represents the core of a space vehicle more powerful than anything the world has seen since the 1960s.

It’s called the Space Launch System (SLS) and it consists of the liquid-fuelled core stage – with four powerful RS-25 engines at its base – and two solid fuel boosters which are strapped to the sides.

The fully assembled vehicle provides the massive thrust force necessary to blast astronauts off the Earth and hurl them towards the Moon. Under Nasa’s Artemis programme, the next man and the first woman will be despatched to the lunar surface in 2024. It will be the first crewed landing on Earth’s only natural satellite since Apollo 17 in 1972.

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  • Nasa Moon rocket core leaves for testing
  • Artemis: To the Moon and Beyond

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SLS graphic

It may use technology developed for the space shuttle, but in many ways, the SLS is a modern heir to the Saturn V, the gigantic rocket that lofted the Apollo lunar missions.

After a decade of development, the SLS is now approaching a critical stage. A year-long programme of testing for the core stage is coming to an end. Called the Green Run, it’s designed to iron out any issues before the rocket’s maiden flight, scheduled for November 2021.

On 12 January this year, the first SLS core stage was shipped to Stennis on a barge from the New Orleans factory where it was assembled. It was then lifted by cranes and installed in a vertical position on the B-2 test stand.

Ryan McKibben, SLS Green Run test conductor at Stennis Space Center, told BBC News: “When you actually see the real deal, with the real avionics, the real tanks – the liquid hydrogen tank which holds 500,000 gallons and the liquid oxygen tank with over 200,000 gallons – it is an incredible vehicle.”

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SLS

NASA

The Green Run is split into eight parts – or test cases. Since the beginning of the year, engineers from Nasa and Boeing, the rocket’s prime contractor, have been working through these individual tests. They have included powering up the avionics (flight electronics), evaluating the performance of different systems and components, and simulating problems.

“We’re very fortunate to be able to put it through its paces: power it up, do leak checks, even pressurise some systems,” says Ryan McKibben.

“One of the test cases, test case five, we ended up gimballing the engines – that’s when we move them around hydraulically so that you can do course corrections during flight. It’s been a lot of fun.”

During its first mission next year, known as Artemis-1, the SLS will launch an uncrewed Orion capsule on a loop around the Moon. It will allow Nasa to evaluate the capsule before astronauts are allowed on.

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Core stage

NASA

The remaining two core stage tests are crucial. Number seven, known as the wet dress rehearsal (WDR) involves a full loading of the core stage tanks with liquid hydrogen (LH2) – the rocket’s fuel – and liquid oxygen (LOX), which makes the fuel burn. Together, these are known as propellants.

A waterway snakes through the grounds of Stennis Space Center, linking it to the nearby Pearl River. This allows heavy equipment and hardware to be shipped between different Nasa sites. A total of six barges carrying LH2 and LOX will be docked near the B-2 test stand during the wet dress rehearsal.

The cold (cryogenic) propellants will be piped from these barges to the core stage tanks. This is relatively easy with hydrogen – a very light gas, but oxygen is heavy, and has to be pumped.

The loading will take place over about six-and-a-half hours. After the tanks are full, they will be continually topped up, because the propellants are at temperatures of several hundreds of degrees below zero and boil off over time.

Engineers will gather data and compare it against mathematical models to check that the entire system behaves as expected.

The Stennis teams will simulate a launch countdown during the WDR, taking things up to the T-minus (time remaining) 33 seconds mark.

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Workers inside the SLS hydrogen tank use a technique called friction stir welding to plug holes

NASA / Michoud / Steve Seipel

“We’ll spend about two weeks looking at the data to make sure all the systems behaved as expected,” John Shannon, vice president and SLS programme manager at Boeing, told journalists last month.

“We’ll go out and inspect the vehicle, make sure there are no surprises.”

The eighth and final test, called the engine “hotfire”, will pick up from the 33-second mark. With the core stage anchored to the stand, the hotfire will see its four powerful RS-25 engines fired together for the first time.

“It’s a full duration burn – that’s what we’re targeting,” said Mr McKibben. “It’s exciting to light more than one off at the same time… We haven’t done that for close to 40 years at the site.”

Aside from the engineering data it will generate, the test will demonstrate the awesome power of the SLS.

The engines – the same ones that powered the now-retired space shuttle orbiter – will generate a whopping 1.6 million pounds of thrust. That’s roughly the same as six 747 airliners at full power.

Although the propellants are at hundred of degrees below freezing when they’re fed to the RS-25 engines, the exhaust that emerges is 3,315C (6,000F) – hot enough to boil iron.

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“We fire down into a bucket that has a lot of water going into it. The water keeps it from burning straight through the test stand,” said Ryan McKibben.

Hundreds of thousands of gallons of water are directed into the flame bucket to cool the exhaust. In addition, tens of thousands of gallons will be used to create a water “curtain” around the engines to suppress the noise generated when they fire for 8.5 minutes.

This is done to protect the core stage from vibrations while it is anchored to the stand.

“We are definitely excited, because you don’t get to try out a new space vehicle very often,” says McKibben.

Engineers have recently been troubleshooting an issue with a pre-valve, which supplies liquid hydrogen fuel to the RS-25 engines. But Mr McKibben says this is “something we’re more than capable of handling”.

The testing has largely proceeded smoothly, but there was a five-week stop due to Covid-19. In addition, work at the site also had to be shut down six times due to tropical weather, given the particularly active hurricane season.

SLS leaves the launchpad

NASA

Originally scheduled to take place in early to mid-November, the wet dress rehearsal and hotfire are now expected to take place with the next six to three weeks.

Teams are conscious of meeting a January timeline for delivering the core stage to Kennedy Space Center in Florida, where it will undergo final processing and preparations for launch in November 2021.

McKibben says he believes teams can still meet this schedule, but adds that it depends on how the core performs during WDR.

The SLS has long been a lightning rod for those who would prefer Nasa to hand over more of its activities to commercial companies, and those who believe the government rocket, designed specifically to carry humans and based on proven technology, is the best option for deep space exploration.

The SLS will have cost more than $17bn by the end of this year, but without significant modifications, no existing commercial rocket can send Orion, astronauts and heavy cargo to the Moon in one go.

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Saturn V

NASA

There is no clear sign as yet of the direction in which a Joe Biden administration might take the human spaceflight programme.

The Artemis effort enjoys bipartisan support. But some Capitol Hill lawmakers may not necessarily be as wedded to the timeline, announced last year by Mike Pence, of landing humans on the Moon by 2024.

There’s no doubt that the Moon programme has recaptured some of the excitement of the Apollo era. Mr McKibben says he is in awe of what the Saturn V engineers did back in the 1960s. It’s not lost on him that the B-2 test stand was built to test the five engines of the Saturn’s first stage.

Going mobile with his laptop, Mr McKibben shows me a car he owns: a navy Dodge Dart from 1969 – the year Neil and Buzz touched down in the Sea of Tranquility.

“It’s something an old test guy that would have been testing the Saturn V would have driven,” he tells me.

“I’m kind of a nostalgic person.”

Follow Paul on Twitter.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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