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India’s ambitious third Moon mission’s spacecraft Chandrayaan-3 on Monday underwent another manoeuvre, bringing it even closer to the Lunar surface, ISRO said.

The national space agency headquartered here said the spacecraft has now achieved a “near-circular orbit” around the moon.

Post its launch on July 14, Chandrayaan-3 entered into the lunar orbit on August 5, following which two orbit reduction manoeuvres were carried out on August 6 and 9.

“Orbit circularisation phase commences. Precise manoeuvre performed today has achieved a near-circular orbit of 150 km x 177 km,” ISRO said in a tweet.

The next operation is planned for August 16, around 8:30 am, it said.

As the mission progresses, a series of manoeuvres are being conducted by ISRO to gradually reduce Chandrayaan-3’s orbit and position it over the lunar poles.

According to ISRO sources, one more manoeuvre will be performed on the spacecraft on August 16 to reach 100 km orbit, following which the landing module, comprising the lander and rover will break away from the propulsion module.

After this, the lander is expected to undergo a “deboost” (the process of slowing down) and make a soft landing on the south polar region of the Moon on August 23.

Last week, ISRO Chairman S Somnath said the most critical part of the landing is the process of bringing the velocity of the lander from 30 km height to the final landing, and that the ability to transfer the spacecraft from horizontal to vertical direction is the “trick we have to play” here.

He said, “The velocity at the start of the landing process is almost 1.68 km per second, but this speed is horizontal to the surface of the moon. The Chandrayaan 3 here is tilted almost 90 degrees, it has to become vertical. So this whole process of turning from horizontal to vertical is a very interesting calculation mathematically. We have done a lot of simulations. It is here where we had the problem last time (Chandrayaan 2).” Further, it has to be ensured that fuel consumption is less, the distance calculation is correct, and all the algorithms are working properly.

“Extensive simulations have gone, guidance design has been changed, and a lot of algorithms have been put in place to make sure that in all these phases required dispersions are handled….to attempt to make a proper landing,” he said.

Over five moves in the three weeks since the July 14 launch, ISRO had lifted the Chandrayaan-3 spacecraft into orbits farther and farther away from the Earth. 

Then, on August 1 in a key manoeuvre — a slingshot move — the spacecraft was sent successfully towards the Moon from Earth’s orbit. Following this trans-lunar injection, the Chandrayaan-3 spacecraft escaped from orbiting the Earth and began following a path that would take it to the vicinity of the moon.

Chandrayaan-3 is a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface.

It comprises an indigenous propulsion module, a lander module, and a rover with the objective of developing and demonstrating new technologies required for inter-planetary missions.

The propulsion module will carry the lander and rover configuration till the 100 km lunar orbit. The propulsion module has a Spectropolarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and polarimetric measurements of Earth from the lunar orbit.

The mission objectives of Chandrayaan-3 are to demonstrate a safe and soft landing on the lunar surface, to demonstrate rover roving on the Moon, and to conduct in-situ scientific experiments.

The lander will have the capability to soft land at a specified lunar site and deploy the rover that will carry out in-situ chemical analysis of the Moon’s surface during the course of its mobility.

The lander and the rover have scientific payloads to carry out experiments on the lunar surface. 


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A Nearby Supernova May End Dark Matter Search, Claims New Study

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A Nearby Supernova May End Dark Matter Search, Claims New Study

The pursuit of understanding dark matter, which comprises 85 percent of the universe’s mass, could take a significant leap forward with a nearby supernova. Researchers at the University of California, Berkeley, led by Associate Professor of Physics Benjamin Safdi, have theorised that the elusive particle known as the axion might be detected within moments of gamma rays being emitted from such an event. Axions, predicted to emerge during the collapse of a massive star’s core into a neutron star, could transform into gamma rays in the presence of intense magnetic fields, offering a potential breakthrough in physics.

Potential Role of Gamma-Ray Telescopes

The study was published in Physical Review Letters and revealed that the gamma rays produced from axions could confirm the particle’s mass and properties if detected. The Fermi Gamma-ray Space Telescope, currently the only gamma-ray observatory in orbit, would need to be pointed directly at the supernova, with the likelihood of this alignment estimated at only 10 percent. A detection would revolutionise dark matter research, while the absence of gamma rays would constrain the range of axion masses, rendering many existing dark matter experiments redundant.

Challenges in Catching the Event

For detection, the supernova must occur within the Milky Way or its satellite galaxies—an event averaging once every few decades. The last such occurrence, supernova 1987A, lacked sensitive enough gamma-ray equipment. Safdi emphasised the need for preparedness, proposing a constellation of satellites, named GALAXIS, to ensure 24/7 sky coverage.

Axion’s Theoretical Importance

The axion, supported by theories like quantum chromodynamics (QCD) and string theory, bridges gaps in physics, potentially linking gravity with quantum mechanics. Unlike neutrinos, axions could convert into photons in strong magnetic fields, providing unique signals. Laboratory experiments like ABRACADABRA and ALPHA are also probing for axions, but their sensitivity is limited compared to the scenario of a nearby supernova. Safdi expressed urgency, noting that missing such an event could delay axion detection by decades, underscoring the high stakes of this astrophysical endeavour.

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Fastest-Moving Stars in the Galaxy May be Piloted by Aliens, New Study Suggests

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Fastest-Moving Stars in the Galaxy May be Piloted by Aliens, New Study Suggests

Intelligent extraterrestrial civilisations might be utilising stars as massive interstellar vehicles to explore the galaxy, according to a theory proposed by Clement Vidal, a philosopher at Vrije Universiteit Brussel in Belgium. His research suggests that alien species could potentially accelerate their binary star systems to traverse vast cosmic distances. While such a concept is purely hypothetical and unproven, Vidal’s recent paper, which has not undergone peer review, raises intriguing possibilities about advanced extraterrestrial engineering.

Concept of Moving Star Systems

The study was published in the Journal of the British Interplanetary Society. As per a report by LiveScience, the idea revolves around the notion that alien civilisations, instead of building spacecraft for interstellar travel, might manipulate entire star systems to travel across the galaxy. Vidal highlights binary star systems, particularly those involving neutron stars and smaller companion stars, as ideal candidates. Neutron stars, due to their immense gravitational energy, could serve as anchors for devices designed to propel the system by selectively ejecting stellar material.

Vidal explained in the paper that uneven heating or manipulation of magnetic fields on a star’s surface could cause it to eject material in one direction. This process would create a reactionary thrust, propelling the binary system in the opposite direction. The concept provides a way to travel while preserving planetary ecosystems, making it a theoretically viable method for species reliant on their home systems.

Known Examples with High Velocities

Astronomers have identified hypervelocity stars, such as the pulsars PSR J0610-2100 and PSR J2043+1711, which exhibit high accelerations. While their movements are believed to be natural phenomena, Vidal suggests they could be worth further investigation to rule out potential artificial influences.

This theory adds an unconventional angle to the search for intelligent life, expanding possibilities beyond traditional methods of exploration like searching for signals or probes. The research underscores the importance of considering advanced and unconventional methods aliens might employ to navigate the galaxy.

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Hubble Telescope Finds Unexpectedly Hot Accretion Disk in FU Orionis

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Hubble Telescope Finds Unexpectedly Hot Accretion Disk in FU Orionis

NASA’s Hubble Space Telescope has provided new insights into the young star FU Orionis, located in the constellation Orion. Observations have uncovered extreme temperatures in the inner region of its accretion disk, challenging current models of stellar accretion. Using Hubble’s Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph, astronomers captured far-ultraviolet and near-ultraviolet spectra, revealing the disk’s inner edge to be unexpectedly hot, with temperatures reaching 16,000 kelvins—almost three times the Sun’s surface temperature.

A Star’s Bright Outburst Explained

First observed in 1936, FU Orionis became a hundred times brighter in months and has remained a unique object of study. Unlike typical T Tauri stars, its accretion disk touches the stellar surface due to instabilities. These are caused by the disk’s large mass, interactions with companion stars, or material falling inwards. Lynne Hillenbrand, a co-author from Caltech, in a statement said that the ultraviolet brightness seen exceeded predictions, revealing a highly dynamic interface between the star and its disk.

Implications for Planet Formation

As per a report by NASA, the study holds significant implications for planetary systems forming around such stars. The report further quoted Adolfo Carvalho, lead author of the study, saying that while distant planets in the disk may experience altered chemical compositions due to outbursts, planets forming close to the star could face disruption or destruction. This revised model provides critical insights into the survival of rocky planets in young star systems, he further added.

Future Investigations on FU Orionis

The research team continues to examine spectral emission lines in the collected data, aiming to map gas movement in the star’s inner regions. Hillenbrand noted that FU Orionis offers a unique opportunity to study the mechanisms at play in eruptive young stars. These findings, published in The Astrophysical Journal Letters, showcase the ongoing value of Hubble’s ultraviolet capabilities in advancing stellar science.

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