Connect with us

Science

A 'dent' in Earth's magnetic field puzzles scientists – NBC News

Published

on


Scientists are keeping a close eye on a growing “dent” in Earth’s magnetic field over a swath of the Atlantic Ocean that stretches from South Africa westward into Brazil.

In this zone, known as the South Atlantic Anomaly, the magnetic field — the invisible shield that protects the planet from radiation and charged particles from the sun — is weaker than normal. Though it’s not thought to be dangerous to humans, experts say the weak spot could cause glitches or permanent damage to Earth-circling satellites that are exposed to energetic particles as they fly through the region.

“Those particles can wreak havoc on satellite instrumentation, so it’s good to track the South Atlantic Anomaly, and especially its changing shape, so that we can take preventative actions,” Terence Sabaka, a geophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said.

Scientists have known about the weak spot in Earth’s magnetic field for several decades, but new research suggests that the South Atlantic Anomaly is growing, spreading further west toward the Pacific Ocean, and is further weakening.

“Satellite measurements, as well as theoretical modeling, predict that the area will be larger in the next five years or longer, and the strength of the magnetic field in that area will be even lower,” Weijia Kuang, a geophysicist and mathematician at NASA Goddard’s Geodesy and Geophysics Laboratory, said.

July 16, 202000:44

Kuang added that the weak spot also appears to be splitting in two, though it’s not yet known what specifically is driving that process.

Earth’s magnetic field is generated by the constant motion of liquid metal in the planet’s iron-rich outer core, roughly 1,800 miles below the surface. As these molten deposits slosh around, they produce electric currents that power Earth’s magnetic field and effectively turn the planet into a giant bar magnet.

But the constant churning in the outer core means the magnetic field is tilted, which is why the magnetic poles aren’t perfectly aligned with Earth’s geographic North and South poles. These dynamics deep inside the planet also create fluctuations and instability in the magnetic field.

In general, the magnetic field is strongest at the poles and weaker at the equator, but more research is needed to understand the precise cause of the South Atlantic Anomaly.

“It’s like a weakness on top of a weakness,” Sabaka said, adding that although other spots exist where the magnetic field is less intense, the one over the Atlantic is by far the largest and most significant.

Sabaka and Kuang have been mapping the South Atlantic Anomaly, but more data will help them finesse their models and build more accurate forecasts of how the weak spot could change over time.

Kuang said these insights will not only help protect satellites and other spacecraft in orbit around Earth, but could also give scientists a better understanding of processes that have unfolded deep inside the planet over hundreds of thousands or millions of years.

“This provides a very, very important window for us to probe the interior properties of the Earth,” he said, “and to understand the Earth as a whole over its evolution.”

Let’s block ads! (Why?)



Source link

Continue Reading

Science

NASA lays out $28 billion plan to return astronauts to the moon in 2024 – Spaceflight Now

Published

on


Astronaut Harrison “Jack” Schmitt collects lunar rake samples from the moon on the Apollo 17 mission in December 1972. Credit: NASA

NASA officials released a nearly five-year, $28 billion plan Monday to return astronauts to the surface of the moon before the end of 2024, but the agency’s administrator said the “aggressive” timeline set by the Trump administration last year hinges on Congress approving $3.2 billion in the next few months to kick-start development of new human-rated lunar landers.

The plan unveiled Monday contained few new details not previously disclosed by NASA. It assumes crews will launch on NASA’s Space Launch System heavy-lift rocket, fly to the moon’s vicinity on an Orion capsule, then transfer into a commercially-developed lunar lander to ferry the astronauts to and from the lunar surface.

NASA released a new overview document Monday describing the agency’s approach to landing astronauts on the moon for the first time since the Apollo 17 mission in December 1972. The program, named Artemis, encompasses the SLS, Orion, Human Landing Systems, and the Gateway, a human-tended platform in lunar orbit that will eventually serve as a staging point for missions to the moon.

“NASA has all the key systems and contracts in place to ensure that we are meeting the president’s ambitious goal to return American astronauts to the moon for the first time since 1972,” said NASA Administrator Jim Bridenstine.

The Trump administration last year directed NASA to land the first woman and the next man on the moon by the end of 2024, moving up the space agency’s previous moon landing schedule by four years.

Bridenstine acknowledged the challenge of landing astronauts on the moon in four years. Three companies — Blue Origin, Dynetics and SpaceX — are developing human-rated lunar landers for NASA, which plans next year to select one or two of the lander teams to continue work on their spacecraft.

“There’s a number of different risks when you deal with human spaceflight,” Bridenstine said. “NASA is really really good at dealing with the technical risks.”

“The challenge that we have is the political risk — the programs that go too long, that cost too much, and that end up getting cast out later in the development program,” Bridenstine said, adding that programs that develop over longer schedules often end up with higher overall costs. “So to save money, and to reduce political risk, we want to go fast … 2024 is an aggressive timeline. Is it possible? Yes. Does everything have to go right? Yes.”

Artist’s concept of an Orion spacecraft at the moon. Credit: NASA

The Gateway is not required for the 2024 mission, which is designated Artemis 3. NASA decided earlier this year it would allow the companies developing human-rated lunar lander concepts to propose ways to transport astronauts from lunar orbit to the moon’s surface and back to the Orion spacecraft without using the Gateway, at least for the first landing on Artemis 3.

Bridenstine said Monday the Gateway is “critically important” for creating a “sustainable” lunar exploration program. It will allow lunar landers to be refueled and reused, and help NASA lead the establishment of a base camp on the moon, where engineers will develop the know-how to tap lunar resources like water ice to generate air, drinking water, and rocket fuel.

The Gateway will also have international contributions from Canada, Europe, and Japan.

The lessons learned will ultimately feed into planning a human expedition to Mars, according to NASA.

In the planning document released Monday, NASA outlined a two-step program to initially move fast to get astronauts to the moon by the end of 2024. Then NASA aims to develop an “Artemis Base Camp” by the end of the 2020s near the moon’s south pole, where crews will be able to live and work for months at a time.

The budget estimates in the planning document do not include developments focused on sustaining the lunar program, such as the Gateway station, surface habitats, and rovers.

That does not mean those programs will not be funded in the next year years, NASA said. The first two elements of the Gateway station remain scheduled to be launched together in 2023.

NASA projects the parts of the Artemis program required for the 2024 moon landing — known as Phase 1 — will cost $28 billion through fiscal year 2025, which begins Oct. 1, 2024.

That figure “represents the costs that are associated with the next four years in the Artemis program to land on the moon by 2024. so SLS funding, Orion funding, the Human Landing System, and of course the spacesuits, all of those things that are part of the Artemis program are included in that $28 billion.”

The Orion spacecraft has been in development since 2006 as part of NASA’s Constellation program initiated by the George W. Bush administration. After rising costs and delays, the Obama administration canceled the Constellation program in 2010, but the Orion spacecraft survived in NASA’s revamped deep space exploration program aimed at Mars.

The Space Launch System was announced in 2011 to loft the Orion spacecraft with crews on expeditions in deep space.

Both programs have suffered years of delays, but NASA says the first SLS/Orion test flight — named Artemis 1 — is scheduled for launch by November 2021. The first flight-ready SLS core stage will be test-fired in late October or early November at NASA’s Stennis Space Center in Mississippi, then delivered to the Kennedy Space Center for final assembly with its solid rocket boosters, cryogenic upper stage, and Orion spacecraft.

The segments of the SLS solid boosters, the rocket’s upper stage, and the Orion spacecraft have been completed and are awaiting arrival of the core stage before ground teams begin stacking the launcher inside the Vehicle Assembly Building at Kennedy.

The Artemis 1 mission will test out the Space Launch System and Orion spacecraft on a mission to orbit the moon and return to Earth. No astronauts will fly on Artemis 1.

“That mission will be over a month long, and it’ll be checking out all of the critical systems,” said Kathy Lueders, head of NASA’s human spaceflight directorate.

A mock-up of the Blue Origin-led human-rated lunar lander was recently delivered to NASA’s Johnson Space Center in Houston for simulations and testing. Credit: Blue Origin

Assuming Artemis 1 goes according to plan, the next SLS/Orion launch in 2023 will carry a crew on a 10-day mission around the moon, sending people farther from Earth than ever before.

NASA recently decided to add a rendezvous and proximity operations demonstration to the Artemis 2 flight plan. The astronauts on Artemis 2 will take manual control of their Orion spaceship and pilot the capsule back toward the SLS upper stage after separating from the rocket in a high-altitude orbit around Earth, before setting off on a trajectory toward the moon.

The astronauts will “assess Orion’s handling characteristics” during the manual piloting demo, which will stop short of an actual docking with the upper stage,” NASA officials wrote in the Artemis planning document released Monday The demonstration will “provide provide performance data and operational experience that cannot be readily gained on the ground in preparation for critical rendezvous, proximity operations, docking, as well as undocking operations” beginning on the Artemis 3 mission.

After looping around the moon on a “free return trajectory,” the Artemis 2 astronauts will return to Earth and ride their Orion capsule to a parachute-assisted splashdown at sea.

That will set the stage for Artemis 3, which will use a similar SLS/Orion vehicle to launch the astronauts to rendezvous with a human-rated lander pre-positioned near the moon after launch aboard a commercial rocket. After flying the Orion spacecraft to link up with the lander in a high-altitude lunar orbit, the astronauts will move into the descent vehicle for the final leg of the journey to the moon.

NASA officials anticipate the Artemis 3 crew will spend nearly a week on the lunar surface to conduct at least two, and perhaps four, moonwalk excursions. Then the astronauts will take off and head back to the Orion spacecraft to ferry them back to Earth.

In parallel with the SLS, Orion, and lander test flights, NASA engineers will demonstrate an upgraded spacesuit design on the International Space Station before it is used by astronauts on the lunar surface.

Bridenstine said Monday that NASA could select a “cadre” of astronauts to begin training for Artemis missions, but the agency has no immediate plans to do so. He added that the agency typically assigns space crews about two years before launch.

The NASA chief also said Monday that the Artemis 3 mission’s landing site remains near the moon’s south pole. In a meeting of lunar scientists last week, Bridenstine discussed a hypothetical scenario in which the Artemis 3 astronauts could return to one of the Apollo landing sites in the moon’s equatorial regions if NASA defers plans for a polar landing

“Right now, we have no plans for Artemis 3 for anything other than the south pole,” Bridenstine said Monday.

Scientists have discovered evidence for water ice harbored in permanently shadowed craters near the moon’s south pole, but no mission has landed there yet. NASA plans to send robotic precursors to the south pole region in the next few years, including a rover named VIPER that will attempt to study the ice deposits up close.

The core stage for NASA’s first Space Launch System heavy-lift rocket was hoisted into a vertical test stand in January at NASA’s Stennis Space Center in Mississippi for testing that will culminate in a hotfire of the rocket’s four main engines. Credit: NASA

The chances of achieving a lunar landing with astronauts in 2024 depend on winning support in Congress, and that support is not assured.

“The budget request that we have before the House and the Senate right now includes $3.2 billion for the Human Landing System,” Bridenstine said. “It is critically important that we get that $3.2 billion.”

A draft budget for NASA passed by the House in July would provide $628 million for lunar lander development in fiscal year 2021, which begins Oct. 1. The Senate has not drafted a NASA budget bill for the next fiscal year, and Congress is expected to pass a continuing resolution by the end of September to keep the government running through Election Day, after which lawmakers could pass a budget for the rest of fiscal year 2021.

The continuing resolution would fund government agencies at 2020 levels, and would not include money NASA says it needs for a Human Landing System.

“We need that $3.2 billion for the Human Landing System,” Bridenstine said. “I think that if we can have that done before Christmas, we’re still on track for a 2024 moon landing.”

If Congress passes a longer-term continuing resolution stretching into early next year, perhaps expiring in March, the longer wait for Human Landing System funds would make a 2024 moon landing more challenging, Bridenstine said. “I would argue that we’re still within the realm of possibility because we do have our work underway right now.”

“If we go beyond March and we still don’t have the Human Landing System funded, it becomes increasingly more difficult,” he said Monday in a conference call with reporters. “We want this to be a bipartisan effort, which we have had a lot of success in achieving. We would like to see the $3.2 billion for the Human Landing System funded at the earliest possible opportunity, and the best we can see that happening right now would be with an omnibus appropriations bill some time before the end of the year.”

More than $16 billion of the $28 billion NASA projects needing to make the Artemis 3 mission happen in 2024 will go toward developing a moon lander.

“If Congress doesn’t fund the moon landing program, then it won’t be achieved,” Bridenstine said later in his conference call with reporters Monday. “It’s really that simple. If they push the funding off, our goal would be to get to the moon at the earliest possible opportunity … If they keep delaying the funding, we will go to the moon at the earliest possible opportunity.”

Despite the funding uncertainty, Bridenstine said he is confident NASA will get the lunar lander money.

“I will tell you that there is broad consensus that it is time to go to the moon sustainably, and 2024 is achievable, and we’re working towards that,” he said. “When that omnibus appropriation is complete, I really believe there will be $3.2 billion for a Human Landing System. That could be at the end of the year, and it could be in March.”

Lueders said Monday that the lander teams led by Blue Origin, Dynetics and SpaceX are “hitting every single milestone” under contracts awarded by NASA in April. After advancing their designs and refining their plans, the teams will submit proposals to NASA again ahead of a decision by agency managers early next year on which lander concepts provide the best chance of achieving a crewed landing on the moon by the end of 2024.

NASA’s budget will be a key factor in determining whether the space agency has to pick one lunar lander team to go forward, or if NASA can afford to keep funding two concepts.

“We would really like to maintain competition,” Lueders said.

NASA has set up the HLS program as a public-private partnership, in which the government and companies share the cost of developing the landing vehicles.

Two of the lead contractors vying to build NASA’s first human-rated lunar lander in 50 years are Blue Origin and SpaceX, led by billionaires Jeff Bezos and Elon Musk. Bridenstine said companies could supply more private funding to make up for a potential shortfall in the NASA budget.

“We are getting our final proposals from the each of the (HLS) provides right now, and it would also be nice to look at different opportunities for different financing, and what that would mean for us,” Lueders said.

She said NASA officials will evaluate their options in the “February/March timeframe” of next year before finalizing the HLS procurement strategy.

SpaceX’s lander is a derivative of the Starship transportation system the company is privately developing. Blue Origin’s concept involves a descent element the company will build itself, along with a crew cabin from Lockheed Martin, and a propulsive transfer stage from Northrop Grumman.

“With a public-private partnership, the companies themselves could actually step up to the plate in a bigger way,” Bridenstine said. “That is something that needs to be seriously considered. Our goal is to create the plan that best optimizes our ability to land on the moon by 2024, but certainly if the money doesn’t materialize, could they do it with their own resources? I’ll leave it to them to make their own determination.”

Email the author.

Follow Stephen Clark on Twitter: @StephenClark1.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

New NASA images show 'fresh ice' forming on Saturn’s moon – Yahoo Canada Sports

Published

on


In these detailed infrared images of Saturn's icy moon Enceladus, reddish areas indicate fresh ice that has been deposited on the surface. Image Credit: NASA

View photos

In these detailed infrared images of Saturn’s icy moon Enceladus, reddish areas indicate fresh ice that has been deposited on the surface. (Nasa)
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Composite images captured by an orbiting Nasa spacecraft have offered hints that fresh ice is forming in several areas on Saturn’s mysterious moon Enceladus.” data-reactid=”32″>Composite images captured by an orbiting Nasa spacecraft have offered hints that fresh ice is forming in several areas on Saturn’s mysterious moon Enceladus.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="With Geyser-like plumes of ice erupting from the surface of the moon, scientists have suggested that life could lurk in its subsurface ocean.” data-reactid=”33″>With Geyser-like plumes of ice erupting from the surface of the moon, scientists have suggested that life could lurk in its subsurface ocean.

The data shows that fresh ice is forming not just near the plumes, but in other areas of the moon, which looks like a reflective, bright white snowball to the naked eye.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: Astronomers find closest black hole to Earth” data-reactid=”35″>Read more: Astronomers find closest black hole to Earth

Gabriel Tobie, VIMS scientist with the University of Nantes in France, said: “The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there.

“Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines.”

Close-Up Of Saturn Against Black BackgroundClose-Up Of Saturn Against Black Background

View photos

Nasa’s Cassini probe captured the data while orbiting Saturn. (Getty)

Enceladus’s ocean is likely heated and churned by hydrothermal vents like those on Earth’s ocean floors.

Some theories have suggested that such environments were where life first arose on Earth.

The researchers said that the same infrared features seen near the plumes also appear in the northern hemisphere.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: There might once have been life on the moon” data-reactid=”61″>Read more: There might once have been life on the moon

That tells scientists not only that the northern area is covered with fresh ice but that the same kind of geologic activity – a resurfacing of the landscape – has occurred in both hemispheres.

The resurfacing in the north may be due either to icy jets or to a more gradual movement of ice through fractures in the crust, from the subsurface ocean to the surface.

Managed by Nasa’s Jet Propulsion Laboratory in southern California, Cassini was an orbiter that observed Saturn for more than 13 years before exhausting its fuel supply. 

The mission plunged it into the planet’s atmosphere in September 2017.

While it still orbited Saturn, Cassini sampled a plume of material erupting from Enceladus’s surface, and analysis of the material suggested an environment where life could flourish inside the moon.

Researchers led by Lucas Fifer of the University of Washington found that the plumes are chemically different from the ocean beneath – changed by their 800mph eruption into space.

It means that the surface of the moon could be much more hospitable to life than previously believed.

Fifer said: “Those high levels of carbon dioxide also imply a lower and more Earth-like pH level in the ocean of Enceladus than previous studies have shown. This bodes well for possible life.

“Although there are exceptions, most life on Earth functions best living in or consuming water with near-neutral pH, so similar conditions on Enceladus could be encouraging.”

Let’s block ads! (Why?)



Source link

Continue Reading

Science

'Crazy year up north' as Arctic ice shrinks to near record-low – Al Jazeera English

Published

on


Ice in the Arctic Ocean melted to its second lowest level on record this year, scientists announced on Monday, in yet another sign of how global warming is rapidly transforming the polar region.

Satellites recorded this year’s sea ice minimum at 3.74 million square km on September 15, only the second time the ice has been measured below 4 million square km in 40 years of record keeping, according to researchers at the United States’s National Snow and Ice Data Center.

“It’s been a crazy year up north, with sea ice at a near-record low… heat waves in Siberia, and massive forest fires,” said Mark Serreze, director of the NSIDC.

“The year 2020 will stand as an exclamation point on the downward trend in Arctic sea ice extent. We are headed towards a seasonally ice-free Arctic Ocean, and this year is another nail in the coffin.”

This year’s melt is second only to 2012, when the ice shrank to 3.4 million square km following a late-season cyclonic storm.

Arctic sea ice reaches its low point in September and its high in March after the winter, and in the 1980s, the ice cover was about 2.7 million square km bigger than the current summer levels.

This year’s decline was especially fast between August 31 and September 5, because of pulses of warm air from a heat wave in Siberia, according to the NSIDC. The rate of ice loss during those six days was faster than during any other year on record.

Arctic Siberian town hit with record heatwave (2:53)

Temperatures in the Siberian Arctic were 8 to 10 degrees Celsius above normal for much of the year, and another team of scientists found in July that the Siberian heatwave would have been all but impossible without human-caused climate change.

Studies show that the warming of the Arctic and the melting of sea ice change weather further south, by altering the jet stream and other waves that move weather systems.

Intensifying warming

As the Arctic sea ice vanishes, it leaves patches of dark water open. Those dark waters absorb solar radiation rather than reflecting it back out of the atmosphere, a process that amplifies warming and helps to explain why Arctic temperatures have risen more than twice as fast as the rest of the world over the last 30 years.

The loss of sea ice also threatens Arctic wildlife, from polar bears and seals to plankton and algae, said Tom Foreman, a polar wildlife expert and Arctic guide.

“The numbers that we’re getting in terms of extent of sea ice decrease each year put us pretty much on red alert in terms of the level of worry that we have, our concern for the stability of this environment,” Foreman said.

The same warming that is opening summertime Arctic waters is also eating away at the ice sheets covering Arctic lands in Canada and Greenland. The faster those ice sheets melt into surrounding ocean, the faster sea levels will rise worldwide.

“The rapid disappearance of sea ice is a sobering indicator of how closely our planet is circling the drain,” Greenpeace Nordic Oceans campaigner Laura Meller said in a statement.

INSIDE STORY | Is the coronavirus pandemic a chance to tackle climate change? (24:56)

“Over the past decades we have lost two-thirds of the volume of the Arctic sea ice, and as the Arctic melts the ocean will absorb more heat and all of us will be more exposed to the devastating effects of climate breakdown,” she later told the AFP news agency from a ship on the edge of the sea ice.

“What we are seeing here in the Arctic is really the opening up of a new ocean on top of the world, which means that we need to be protecting the area.”

The 2015 landmark Paris climate deal enjoins nations to limit global temperature rises to “well below” two degrees Celsius through a rapid and sweeping reduction in greenhouse gas emissions.

But emissions have continued to rise despite the deal, and several analyses have warned that without a thoroughly re-tooled global economy prioritising green growth, the pollutions savings due to the COVID-19 pandemic will have an insignificant mitigating effect on climate change.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending