A new crystalline form of water ice has been discovered in fleeting transitions between phases at high pressures.
It’s called Ice-VIIt, and it takes place as the substance slides between two already known, cubic arrangements of molecules. Although it’s unlikely Ice-VIIt would naturally appear on Earth’s surface, it could reveal more about how water behaves on massive alien worlds.
We might think it commonplace, but water is actually pretty weird compared to other liquids we know. The arrangement of molecules within water’s frozen form – ice – can vary significantly, depending on the conditions around it.
We know of at least 19 of these solid phases of ice, some of which occur naturally, some of which have only been seen in laboratory conditions.
The ice you see in the freezer, or falling from the sky as snowflakes or hailstones, is the most common natural ice on Earth. It is called Ice-I, with oxygen atoms arranged in a hexagonal grid. The structure is, however, geometrically frustrated, with the hydrogen atoms hanging about in a disorderly fashion.
When physicists cool Ice-I at various temperatures and apply different pressures to it, the hydrogen and oxygen atoms within can periodically reach different arrangements, sometimes even ordering themselves more neatly. These various forms of water ice are not always stable, but we can explore these in the lab to reveal their curious molecular structures.
Two of these phases that have cubic structures are Ice-VII, which has disordered hydrogen, and Ice-X, which is symmetric. These can be reached by subjecting ice to high pressures tens to hundreds of thousands greater than Earth’s atmospheric pressure at sea level, Ice-VII at even lower pressures than Ice-X.
To study the transitions between ice phases, a team of physicists led by Zach Grande of the University of Nevada, Las Vegas performed experiments on high pressure ice using a new technique to measure the properties of the ice as pressure was applied.
The researchers squeezed a sample of water in a diamond anvil, forcing it to freeze in a jumble of crystals. Lasers were used to then heat the sample, causing it to melt before re-freezing into what the researchers described as a powder-like collection of crystals.
By incrementally raising the pressure in the anvil, with periodic blasts from the laser, the researchers created Ice-VII, and observed the transition to Ice-X. In between, thanks to their new measurement technique, they also observed the new intermediate phase, Ice-VIIt.
In this phase, the cubic lattice of Ice-VII is stretched along one of its vectors so that the structure extends into a rectangular arrangement, with a cubic footprint, before settling into the symmetric, fully ordered cubic arrangement of Ice-X. This arrangement is known as tetragonal.
The team also showed that Ice-X can form at much lower pressures than previously thought. Ice-VII forms from approximately 3 gigapascals; that is, 30,000 atmospheric pressures. According to the team’s observations, the transition to Ice-VIIt occurs at around 5.1 gigapascals.
Previous reports have put the transition pressure for Ice-X between 40 and 120 gigapascals. However, Grande and his team observed the transition between Ice-VIIt and Ice-X occurring at around 30.9 gigapascals.
This, the team said, should help resolve the debate about the Ice-X transition pressure.
“Zach’s work has demonstrated that this transformation to an ionic state occurs at much, much lower pressures than ever thought before,” said physicist Ashkan Salamat of the University of Nevada, Las Vegas.
“It’s the missing piece, and the most precise measurements ever on water at these conditions.”
This, the team said, could have important implications for studying the interior conditions of other worlds. Water-rich planets outside the Solar System could, they said, have Ice-VIIt in abundance, even increasing the chance of conditions suitable for the emergence of life.
The team’s research has been published in Physical Review B.
After 45 years, NASA's Voyager 1 space probe encounters mystery issue – CP24 Toronto's Breaking News
(CNN) — The Voyager 1 probe is still exploring interstellar space 45 years after launching, but it has encountered an issue that mystifies the spacecraft’s team on Earth.
Voyager 1 continues to operate well, despite its advanced age and 14.5 billion-mile distance (23.3 billion kilometers) from Earth. And it can receive and execute commands sent from NASA, as well as gather and send back science data.
But the readouts from the attitude articulation and control system, which control the spacecraft’s orientation in space, don’t match up with what Voyager is actually doing. The attitude articulation and control system, or AACS, ensures that the probe’s high-gain antenna remains pointed at Earth so Voyager can send data back to NASA.
Due to Voyager’s interstellar location, it takes light 20 hours and 33 minutes to travel one way, so the call and response of one message between NASA and Voyager takes two days.
So far, the Voyager team believes the AACS is still working, but the instrument’s data readouts seem random or impossible. The system issue hasn’t triggered anything to put the spacecraft into “safe mode” so far. That’s when only essential operations occur so engineers can diagnose an issue that would put the spacecraft at risk.
And Voyager’s signal is as strong as ever, meaning the antenna is still pointed to Earth. The team is trying to determine if this incorrect data is coming directly from this instrument or if another system is causing it.
“Until the nature of the issue is better understood, the team cannot anticipate whether this might affect how long the spacecraft can collect and transmit science data,” according to a NASA release.
“A mystery like this is sort of par for the course at this stage of the Voyager mission,” said Suzanne Dodd, project manager for Voyager 1 and 2 at NASA’s Jet Propulsion Laboratory in Pasadena, California, in a statement.
“The spacecraft are both almost 45 years old, which is far beyond what the mission planners anticipated. We’re also in interstellar space — a high-radiation environment that no spacecraft have flown in before. So there are some big challenges for the engineering team. But I think if there’s a way to solve this issue with the AACS, our team will find it.”
If the team doesn’t determine the source of the issue, they may just adapt to it, Dodd said. Or if they can find it, the issue may be solved by making a software change or relying on a redundant hardware system.
Voyager has already relied on backup systems to last as long as it has. In 2017, the probe fired thrusters that were used during its initial planetary encounters during the 1970s — and they still worked after remaining unused for 37 years.
The aging probes produce very little power per year, so subsystems and heaters have been turned off over the years so that critical systems and science instruments can keep operating.
Voyager 2, a twin spacecraft, continues to operate well in interstellar space 12.1 billion miles (19.5 billion kilometers) from Earth. By comparison, Neptune, the farthest planet from Earth, is, at most, only 2.9 billion miles away. Both probes were launched in 1977 and have far exceeded their original purpose to fly by planets.
Now, they have become the only two spacecraft to gather data from interstellar space and provide insights about the heliosphere, or the bubble created by the sun that extends beyond the planets in our solar system.
Boeing's Starliner ready to launch to space station on 2nd test flight – CBC.ca
Boeing’s new Starliner capsule was set for launch on Thursday on a do-over uncrewed test flight to the International Space Station, aiming to deliver the company a much-needed success after two years of delays and costly engineering setbacks.
The gumdrop-shaped CST-100 Starliner was scheduled for liftoff at 6:54 p.m. ET from the Cape Canaveral Space Force Station in Florida, carried atop an Atlas V rocket furnished by the Boeing-Lockheed Martin joint venture United Launch Alliance (ULA).
ULA said Wednesday evening forecasts called for a 70 per cent chance of favourable weather conditions for an on-time launch.
If all goes as planned, the capsule will arrive at the space station about 24 hours later, docking with the research outpost orbiting some 400 kilometres above Earth at 7:10 p.m. ET on Friday.
The <a href=”https://twitter.com/BoeingSpace?ref_src=twsrc%5Etfw”>@BoeingSpace</a> <a href=”https://twitter.com/hashtag/Starliner?src=hash&ref_src=twsrc%5Etfw”>#Starliner</a> counts down to liftoff at 6:54pm ET today as the Exp 67 crew preps for its Friday arrival and keeps up human research. <a href=”https://t.co/PqF6Pkbf9Z”>https://t.co/PqF6Pkbf9Z</a>
The Boeing craft is to spend four to five days attached to the space station before undocking and flying back to Earth, with a parachute landing cushioned by airbags on the desert floor of White Sands, New Mexico.
A successful mission will move the long-delayed Starliner a major step closer to providing NASA with a second reliable means of ferrying astronauts to and from the International Space Station (ISS).
Since resuming crewed flights to orbit from American soil in 2020, nine years after the space shuttle program ended, the U.S. space agency has had to rely solely on the Falcon 9 rockets and Crew Dragon capsules flown by Elon Musk’s company SpaceX.
Payload and model passenger
The Starliner will not be flying to orbit empty. The capsule will carry a research mannequin to collect data on crew cabin conditions during the journey, plus 500 pounds of cargo for delivery to the space station’s crew — three NASA astronauts, a European Space Agency astronaut from Italy and three Russian cosmonauts.
Two of the U.S. astronauts will be tasked with boarding the capsule during Starliner’s stay to take measurements of its interior environment and unload the supplies.
Thursday’s launch marks a repeat of a 2019 test mission that failed to achieve a successful rendezvous with the space station because of a flight-software malfunction. Subsequent problems with Starliner’s propulsion system, supplied by Aerojet Rocketdyne, led Boeing to scrub an attempt to launch the capsule last summer.
The spacecraft remained grounded for nine more months while the two companies sparred over what caused its fuel valves to stick shut and which firm was responsible for fixing them.
Boeing says it has since resolved the glitch with a temporary workaround and plans to redesign the propulsion system’s fuel valves system after this week’s flight.
Starliner was developed with a $4.5 billion US fixed-price NASA contract to provide the U.S. space agency a second avenue to low-Earth orbit, along with SpaceX, and has proven costly to Boeing.
Delays and engineering setbacks with Starliner have led the aerospace giant to take $595 million US in charges since the capsule’s 2019 failure, even as the company strives to climb out of successive crises in its jetliner business and its space-defence unit.
If the second uncrewed trip to orbit succeeds, Starliner could fly its first team of astronauts in the fall, though NASA officials caution that time frame could get pushed back.
NASA astronauts Butch Wilmore and Mike Fincke had been designated to fly Starliner’s maiden crewed mission. But NASA officials, reluctant to tie down two astronauts to a flight whose launch date is uncertain, said Wednesday the mission could end up carrying at least two of any of the four astronauts now training to test-fly Starliner.
Dusty demise for NASA Mars lander in July; power dwindling – CGTN
A NASA spacecraft on Mars is headed for a dusty demise.
The InSight lander is losing power because of all the dust on its solar panels. NASA said Tuesday it will keep using the spacecraft’s seismometer to register marsquakes until the power peters out, likely in July. Then flight controllers will monitor InSight until the end of this year, before calling everything off.
“There really hasn’t been too much doom and gloom on the team. We’re really still focused on operating the spacecraft,” said Jet Propulsion Laboratory’s Bruce Banerdt, the principal scientist.
Since landing on Mars in 2018, InSight has detected more than 1,300 marsquakes; the biggest one, a magnitude 5, occurred two weeks ago.
It will be NASA’s second Mars lander lost to dust: A global dust storm took out Opportunity in 2018. In InSight’s case, it’s been a gradual gathering of dust, especially over the past year.
NASA’s two other functioning spacecraft on the Martian surface – rovers Curiosity and Perseverance – are still going strong thanks to nuclear power. The space agency may rethink solar power in the future for Mars, said planetary science director Lori Glaze, or at least experiment with new panel-clearing tech or aim for the less-stormy seasons.
InSight currently is generating one-tenth of the power from the sun that it did upon arrival. Deputy project manager Kathya Zamora Garcia said the lander initially had enough power to run an electric oven for one hour and 40 minutes; now it’s down to 10 minutes max.
The InSight team had anticipated this much dust buildup, but hoped a gust of wind or dust devil might clean off the solar panels. That has yet to happen, despite several thousand whirlwinds coming close.
“None of them have quite hit us dead-on yet enough to blow the dust off the panels,” Banerdt told reporters.
Another science instrument, dubbed the mole, was supposed to burrow 16 feet (5 meters) underground to measure the internal temperature of Mars. But the German digger never got deeper than a couple of feet (a half-meter) because of the unexpected composition of the red dirt, and it finally was declared dead at the beginning of last year.
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