Chinese rocket tumbling uncontrolled back to Earth

A large segment of a Chinese rocket is expected to make an uncontrolled re-entry into the Earth’s atmosphere on the weekend, but Beijing has downplayed fears and said there is a very low risk of any damage.

A Long March-5B rocket launched the first module of China’s new space station into Earth’s orbit on April 29. Its 18-tonne main segment is now in freefall and experts have said it is difficult to say precisely where and when it will re-enter the atmosphere.

Re-entry is expected to be around 2300 GMT on Saturday, according to the Pentagon, with a window of nine hours either side.

Chinese authorities have said most of the rocket components would likely be destroyed on re-entry.

“The probability of causing harm… on the ground is extremely low,” Chinese foreign ministry spokesman Wang Wenbin told reporters on Friday.

Although there has been fevered speculation over exactly where the rocket—or parts of it—will land, there is a good chance any debris that does not burn up will just splash down into the ocean, given that the planet is 70 percent water.

“We’re hopeful that it will land in a place where it won’t harm anyone,” said Pentagon spokesman Mike Howard.

Howard said the United States was tracking the rocket segment but “its exact entry point into the Earth’s atmosphere cannot be pinpointed until within hours of its re-entry”.

Defense Secretary Lloyd Austin earlier said that the US military had no plans to shoot it down, and suggested that China had been negligent in letting it fall out of orbit.

“Given the size of the object, there will necessarily be big pieces left over,” said Florent Delefie, an astronomer at the Paris-PSL Observatory.

“The chances of debris landing on an inhabited zone are tiny, probably one in a million.”

In 2020, debris from another Long March rocket fell on villages in the Ivory Coast, causing structural damage but no injuries or deaths.

Jonathan McDowell, an astrophysicist at the Harvard–Smithsonian Center for Astrophysics, said that although there was no need to worry “too much”, the rocket’s design needed a re-think to stop such a scenario happening again.

“There is a real chance of damage to whatever it hits and the outside chance of a casualty,” he said.

“Having a ton of metal shards flying into the Earth at hundreds of kilometres per hour is not good practice, and China should redesign the Long-March 5B missions to avoid this.”

Sources: Phys.org

Lawrence Krauss on the Universe

“… the fact that the universe itself may have no purpose doesn’t affect our purpose, in fact it’s the incredible height of solipsism to assume that without us the universe doesn’t matter, and that if the universe is purposeless we don’t matter. We make our own purpose, and it seems to me life is more precious because it’s temporary and accidental, and we should take advantage of that. And we have evolved brains and that allows us to ask questions not just about how the universe works but how we should behave.”

~ Lawrence Krauss, (born May 27, 1954) is an American-Canadian theoretical physicist and cosmologist who is Foundation Professor of the School of Earth and Space Exploration at Arizona State University, and director of its Origins Project.

#FavoriteQuotes #LawrenceKrauss #Science

NASA Chooses SpaceX to Return Humans to the Moon

NASA has selected SpaceX to land the first astronauts on the surface of the Moon since 1972, the agency said Friday, in a huge victory for Elon Musk’s company.

The contract, worth $2.9 billion, involves the prototype Starship spacecraft that is being tested at SpaceX’s south Texas facility.

“Today I’m very excited, and we are all very excited to announce that we have awarded SpaceX to continue the development of our integrated human landing system,” said Lisa Watson-Morgan, NASA’s Human Landing System program manager.

SpaceX beats out Jeff Bezos’ Blue Origin and defense contractor Dynetics to be the sole provider for the system, a surprising break from the past when NASA has chosen multiple companies in case one fails.

Industry analysts said the decision underscores the company, founded by Musk in 2002 with the goal of colonizing Mars, as NASA’s most trusted private sector partner. 

Last year, SpaceX became the first private firm to successfully send a crew to the International Space Station, restoring American capacity to accomplish the feat for the first time since the Shuttle program ended.

For its Moon lander bid, SpaceX put forward its reusable Starship spacecraft, which is designed to carry large crews and cargo for deep space voyages, and land upright both on Earth and other celestial bodies.

Prototypes of the vessel are currently being put through their paces at the company’s south Texas facility, though all four versions that have so far attempted test flights have exploded.

Under the Artemis program to return humans to the Moon, NASA wants to use the Space Launch System rocket to launch four astronauts on board an Orion crew capsule, which will then dock with a lunar space station called Gateway.

Starship will be waiting to receive two crew members for the final leg of the journey to the surface of the Moon. 

The idea is for Gateway to be the go-between but for the initial mission Orion might dock directly with Starship, Watson-Morgan said.

The astronauts would then spend a week on the Moon before boarding Starship to return to lunar orbit, then take Orion back to Earth.

Separately, SpaceX has plans to combine the Starship spaceship with its own Super Heavy rocket, to make a combined vessel that will tower 394 feet (120 meters) tall and be the most powerful launch vehicle ever deployed.

Humanity last stepped foot on the Moon in 1972 during the Apollo program.

NASA wants to go back and establish a sustainable presence, complete with a lunar space station, in order to test new technologies that will pave the way for a crewed mission to Mars. 

Sources: Phys.org

NASA Mars Helicopter

The helicopter that NASA has placed on Mars could make its first flight over the Red Planet within days after a successful initial test of its rotors, the US space agency said Friday.

The current plan for the first-ever attempt at powered, controlled flight on another planet is for the four-pound (1.8 kilogram) helicopter, dubbed the Ingenuity, to take off from Mars’ Jezero Crater on Sunday at 10:54 pm US eastern time (0254 GMT Monday) and hover 10 feet (3 meters) above the surface for a half-minute, NASA said.

“The helicopter is good, it’s looking healthy,” said Tim Canham, Ingenuity operations lead, in a press conference.

“Last night, we did our 50 RPM spin, where we spun the blades very slowly and carefully,” he said.

The plan for Sunday is to have it rise, flying only vertically, hover and rotate for 30 seconds to take a picture of the Perseverance rover, which touched down on Mars on February 18 with the helicopter attached to its underside.

Then the Ingenuity will be lowered back down onto the surface.

The flight will be autonomous, pre-programmed into the aircraft because of the 15 minutes it takes for signals to travel from Earth to Mars, and also due to the demanding environment of the distant planet.

“Mars is hard not only when you land, but when you try to take off from it and fly around, too,”said MiMi Aung, Ingenuity project manager.

She explained that the planet has significantly less gravity than Earth, but less than one percent the pressure of Earth’s atmosphere at the surface.

The makes it necessary for the Ingenuity to be able to spin its rotor blades much faster than a helicopter on Earth in order to fly.

“Put those things together, and you have a vehicle that demands every input be right,” said Aung.

NASA captured the test of the rotors in a short video shot from the rover just a few meters away, showing what looks like a small drone.

Aung said a second test would be conducted today, with the rotors running at high speed.

“The only uncertainty remains the actual environment of Mars,” she said, mentioning possible winds. 

NASA calls the unprecedented helicopter operation highly risky, but says it could reap invaluable data about the conditions on Mars. 

NASA plans up to five flights, each successively more difficult, in a period of a month.

Source: Phys.org

Southern Ellipse

AM 0644-741, a ring galaxy in Volans

AM 0644-741 (sometimes called The Southern Ellipse) is a ring galaxy, approximately 300 million light-years away in the direction of the southern constellation Volans. It is receding from us at about 6600 km/sec.

The yellowish off-center nucleus was once the center of a normal spiral galaxy and the overlapping/double ring of brilliant blue star clusters, which currently surrounds the center, is some 150,000 light-year in diameter, making it larger than our Milky Way Galaxy.

Ring galaxies are formed when an intruder galaxy plunges directly through the disk of a target galaxy. In the case of AM 0644-741, the galaxy that pierced through the ring galaxy is out of the image but visible in larger-field images.

The collision creates a shock wave that causes the gas and dust to rush outward, somewhat like ripples in a pond after a large rock has been thrown in. As the shock ring plows outward, gas and dust clouds collide, are compressed and then collapse gravitationally to form an abundance of new stars in a ring around the outside.

The rampant star formation explains why the ring is so blue: it is continuously forming massive, young, hot stars, which are blue in color. Another sign of robust star formation is the pink regions along the ring. These are rarefied clouds of glowing hydrogen gas that is fluorescing as it is bombarded with strong ultraviolet light from the blue stars.

Anyone who lives on planets embedded in the ring would be treated to a view of a brilliant band of blue stars arching across the heavens. The view would be relatively short-lived because theoretical studies indicate that the blue ring will not continue to expand forever. After about 300 million years, it will reach a maximum radius, and then begin to disintegrate.

This image is taken by the Hubble Space Telescope.
Image Credit: NASA, ESA, and The Hubble Heritage Team (AURA/STScI)

InSight Detects Two Quakes

NASA’s InSight lander has detected two strong, clear quakes originating in a location of Mars called Cerberus Fossae—the same place where two strong quakes were seen earlier in the mission. The new quakes have magnitudes of 3.3 and 3.1; the previous quakes were magnitude 3.6 and 3.5. InSight has recorded over 500 quakes to date, but because of their clear signals, these are four of the best quake records for probing the interior of the planet.

Studying marsquakes is one way the InSight science team seeks to develop a better understanding of Mars’ mantle and core. The planet doesn’t have tectonic plates like Earth, but it does have volcanically active regions that can cause rumbles. The March 7 and March 18 quakes add weight to the idea that Cerberus Fossae is a center of seismic activity.

“Over the course of the mission, we’ve seen two different types of marsquakes: one that is more ‘Moon-like’ and the other, more ‘Earth-like,'” said Taichi Kawamura of France’s Institut de Physique du Globe de Paris, which helped provide InSight’s seismometer and distributes its data along with the Swiss research university ETH Zurich. Earthquake waves travel more directly through the planet, while those of moonquakes tend to be very scattered; marsquakes fall somewhere in between. “Interestingly,” Kawamura continued, “all four of these larger quakes, which come from Cerberus Fossae, are ‘Earth-like.'”

The new quakes have something else in common with InSight’s previous top seismic events, which occurred almost a full Martian year (two Earth years) ago: They occurred in the Martian northern summer. Scientists had predicted this would again be an ideal time to listen for quakes because winds would become calmer. The seismometer, called the Seismic Experiment for Interior Structure (SEIS), is sensitive enough that, even while it is covered by a dome-shaped shield to block it from wind and keep it from getting too cold, wind still causes enough vibration to obscure some marsquakes. During the past northern winter season, InSight couldn’t detect any quakes at all.

“It’s wonderful to once again observe marsquakes after a long period of recording wind noise,” said John Clinton, a seismologist who leads InSight’s Marsquake Service at ETH Zurich. “One Martian year on, we are now much faster at characterizing seismic activity on the Red Planet.”

Sources: Phys.org