Subject: Space Technology

Introduction

• Juno, a spacecraft launched by NASA in 2011, embarked on a mission to unravel the secrets of Jupiter and its moons.
• En route to Jupiter, Juno encountered fast-moving dust particles, resulting in significant damage to its solar panels.

About NASA’s Juno Mission

Dusts in Interplanetary Space

• Calculating Dust Flux: Scientists harnessed Juno’s data to estimate the flux of dust particles encountered between 1 and 5 Astronomical Units (AU), shedding light on the density and distribution of interplanetary dust.
• Exploring Dust Sources: Analysis suggested Mars’s moons, Deimos and Phobos, as potential sources of interplanetary dust, offering tantalizing clues to unraveling the enigmatic origins of these celestial particles.

How Martian Moons, Deimos and Phobos produce this Dust?

• Micrometeorite Impacts: Micrometeorites, tiny yet potent dust particles, bombard Mars’s moons, creating ephemeral clouds of dust upon impact due to the absence of atmospheres.
• Escape into Space: Deimos and Phobos, characterized by low gravity, facilitate the escape of dust particles into space, contributing to the formation of a dusty ring around Mars.

Insights from Observations

• Gravitational Dynamics: This models incorporated gravitational effects, lunar shapes, and dust particle velocities, offering a comprehensive understanding of the dust dynamics within the Martian system.
• Validation through Future Missions: Prospective missions to Deimos and Phobos hold the promise of validating the recent findings, shedding further light on the dusty realms of these enigmatic moons.

Introduction

• Rotating black holes, also known as Kerr black holes, possess a fascinating region called the ergosphere, which sets them apart from their non-rotating counterparts.

Formation of Black Holes

• Origin: Black holes are born from massive stars that exhaust their nuclear fuel and undergo a supernova explosion. The remaining core collapses under its own gravitational force, forming a black hole.
• Gravitational Singularity: At the core of a black hole lies a gravitational singularity, a point where the laws of general relativity cease to provide accurate predictions.
• Event Horizon: Surrounding the singularity is the event horizon, a boundary beyond which nothing, not even light, can escape. It acts as a point of no return for anything entering it.

What is Ergosphere?

• Ergosphere Description: Beyond the event horizon, rotating black holes feature another unique region known as the ergosphere. This region extends further out from the singularity, creating an additional sphere around the black hole.
• Name Origins: The term ‘ergosphere’ finds its roots in the Greek word ‘ergon,’ which means ‘work.’ It earned this name due to the intriguing possibility it offers – the extraction of matter and energy from this region.

Characteristics of the Ergosphere

• Intriguing Property: Unlike the event horizon, objects can enter the ergosphere and potentially escape from it, provided they move at speeds less than that of light.
• Acceleration Potential: Some scientists have explored the idea of sending objects into the ergosphere to leverage their unique characteristics. Objects within the ergosphere can gain energy and momentum, effectively “borrowing” some of the black hole’s angular momentum.

Introduction

• In the field of astronomy, astronomers sometimes stumble upon celestial objects that leave them scratching their heads.
• In a recent study published in Science, a discovery was reported that is likely to get scientists talking and asking questions.

Neutron Stars: Exceptionally Dense

• Incredibly Dense Objects: Neutron stars are some of the densest things in the universe. They’re as compact as an atomic nucleus but as big as a city, pushing our understanding of super-dense matter to the limit.
• A Weighty Matter: The heavier a neutron star is, the more likely it is to eventually collapse and become something even denser, like a black hole.

Puzzling the Boundary

• A Cosmic Mystery: To understand what happens when neutron stars turn into black holes, objects that are in-between need to be found. These objects also need to be studied very carefully over a long time.
• A New Discovery: A cosmic system has been found in the NGC 1851 star cluster that doesn’t fit neatly into the categories of neutron stars or black holes.

NGC 1851E: The Revelation

• Seeing Something New: Inside NGC 1851, a pair of stars has been spotted that provides fresh insights into the extreme matter in the universe. This system has a millisecond pulsar, a fast-spinning neutron star that sends out beams of radio light, and a massive, dark companion that can’t be seen at any wavelength of light.
• The Pulsar’s Role: Millisecond pulsars are like cosmic clocks. They spin steadily, and any changes in their spin can tell important things about what’s around them.

Unveiling the Weight of Secrets

• Very Precise Measurements: The MeerKAT radio telescope in South Africa was used to closely watch the NGC 1851E system.
• What Was Found: Observations allowed figuring out exactly how the two objects move around each other and how heavy they are together. The system’s mass is almost four times that of the Sun, and the invisible companion is denser than a regular star but not as heavy as a black hole.
• A Strange Mass Gap: The companion’s mass falls in a range that’s puzzling to scientists, between the heaviest neutron stars and the lightest black holes. Understanding objects in this range is a big mystery in astrophysics.

A Stellar Dance: Cosmic Partnerships

• A Fascinating Idea: One intriguing possibility is that a pulsar is circling around what’s left after two neutron stars collided, something made possible because there are many stars packed closely together in NGC 1851.
• Starry Dance Floor: In this crowded group of stars, they twirl around each other, changing partners as they go. If two neutron stars get too close, they collide, creating a black hole. This black hole can then disturb the dance of other stars in the cluster.
• Still Many Questions: The work isn’t finished. Research is continuing to figure out exactly what the companion is. Is it the lightest black hole, the heaviest neutron star, or something completely different?
• Exploring New Frontiers: When at the border between neutron stars and black holes, there’s a chance of discovering completely new types of objects.

Introduction

• In 1967 a group of astronomers at the University of Cambridge stumbled upon a celestial mystery that would unravel the secrets of neutron stars.
• Jocelyn Bell Burnell and Antony Hewish observed periodic signals emanating from the depths of space, eventually discovering the first pulsar, PSR B1919+21.

Pulsars and Neutron Stars

• The Birth of a Pulsar: PSR B1919+21 initially puzzled scientists, who considered various explanations, even the possibility of signals from extraterrestrial life.
• Neutron Stars: Neutron stars are born from the remnants of massive stars that didn’t become black holes. They are incredibly dense and primarily made up of neutrons.

Behind the Radiation: Lighthouse Effect

• Radiation Beams: Pulsars emit focused beams of radio waves, similar to a lighthouse’s rotating light.
• Rotation Slowdown: Neutron stars gradually slow down their rotation, and this process generates the pulsar’s radio signals.

The Mystery of Glitches

• Sudden Speed-Ups: In 1969, scientists noticed unexpected and brief increases in the rotation speed of pulsars, known as “glitches.”
• Unsolved Riddle: Even after more than four decades of study, the cause of these glitches remains a mystery, although scientists have developed some ideas.
• Common Occurrence: Around 700 glitches have been observed in more than 3,000 pulsars.

Clues in the Rotation

• Post-Glitch Behavior: During a glitch, the pulsar’s rotation rate temporarily increases before gradually returning to its previous speed.
• Sign of Internal Changes: The slow post-glitch recovery suggests that the neutrons inside the star behave like a special kind of fluid, called a superfluid, with very low friction.
• Superfluids and Vortices: Superfluids, like the one inside a neutron star, exhibit vortex behavior, which is like tiny whirlpools.

The Glitch Mechanism

• Neutron Star Structure: Neutron stars have a solid outer layer with superfluid patches and a core primarily made of superfluid.
• Vortex Pinning: Vortices within the superfluid like to stick to the crust or solid parts of the star, which keeps the superfluid rotating.
• How Glitches Happen: As the star loses energy over time, the crust slows down, but the pinned vortices stay at their original speed. When the difference becomes too great, the vortices are released, transferring energy from the superfluid to the crust, causing a glitch in the pulsar’s rotation.

Introduction

• NASA’s Mars helicopter, Ingenuity, recently regained contact with Earth after a brief communication lapse during its 72nd flight on the Red Planet.
• This remarkable solar-powered robotic chopper has accomplished groundbreaking feats in extraterrestrial aviation, making history with its powered, controlled flight on Mars.

About Ingenuity 

• Inaugural Flight: Ingenuity landed on Mars on February 18, 2021, alongside the Perseverance Rover. On April 19 of the same year, it achieved the first powered extraterrestrial flight in human history.
• Launch and Deployment: NASA launched a spacecraft on July 30, 2020, carrying the Perseverance rover with Ingenuity attached. The helicopter was deployed on the Martian surface on April 4, 2021, after reaching a suitable “airfield” location.
• Experimental Purpose: Ingenuity’s primary mission was experimental, aiming to test powered, controlled flight on another celestial body.
• Historic Flight: During its maiden flight, Ingenuity hovered, covered the same spot, and remained airborne for an impressive 39.1 seconds, establishing a historic milestone.

Challenges and Impressive Records

• Vast Distances: Despite the relatively short flight duration, Mars’ distance of over 225 million kilometres from Earth results in signal delays of 5 to 20 minutes.
• Harsh Martian Conditions: Ingenuity must endure Mars’ challenging conditions, including low atmospheric density, “continent-sized” dust storms, and various hazards.

Significance of Mars Flight

• Historical Milestone: On April 19, 2021, Ingenuity’s inaugural flight marked two significant achievements. Firstly, it was the first aircraft to fly on another planet. Secondly, it operated in Mars’ thin atmosphere, unsuitable for conventional flight.
• Challenges of Martian Flight: Ingenuity’s flight on Mars was challenging due to the planet’s lower gravity, one-third that of Earth’s, and its extremely thin atmosphere with just 1% of Earth’s surface pressure.
• Autonomous Operation: Ingenuity is an autonomous aircraft, piloted by onboard guidance, navigation, and control systems, running algorithms developed by NASA’s Jet Propulsion Laboratory. Perseverance serves as a crucial link between the chopper and Earth.

Evolving Mission Role

• Scouting and Exploration: Initially designed for a limited number of flights, Ingenuity’s role evolved as scientists began to use it for scouting. It aided Perseverance in exploring Martian terrain efficiently, avoiding unexceptional rocks and enhancing mission productivity.
• Impressive Flight Record: Before the recent communication lapse, Ingenuity completed 72 flights, accumulating more than 128 minutes of flight time and covering a total distance of 17.7 kilometers, as recorded in the mission’s flight log.

Introduction

• India’s Department of Science and Technology (DST) has shown a renewed interest in the global scientific endeavor, the Thirty Meter Telescope (TMT) project, as evidenced by their recent visit to Mauna Kea in Hawai’i.
• This visit marks a significant step in addressing the challenges faced by this ambitious astronomical project.

Overview of the TMT Project

• Project Description: The TMT is envisioned as a 30-metre diameter primary-mirror optical and infrared telescope, designed for deep space observations.
• International Collaboration: It is a joint venture involving the U.S., Japan, China, Canada, and India, with India’s participation approved by the Union Cabinet in 2014.

Key facts related to TMT

• Its 30m diameter prime-mirror will allow it to observe wavelengths ranging from ultraviolet to mid-infrared with up to 80 times more sensitivity of today’s largest telescopes.
• It can deliver images at infrared wavelengths more than 12 times sharper than the famed Hubble Space Telescope and 4 times sharper than James Webb Space Telescope (JSWT).

Challenges and Controversies

• Location Issues: Mauna Kea, the proposed site for the TMT, is an inactive volcano considered sacred by local communities. The site has faced opposition due to its cultural and religious significance.
• Legal Hurdles: The Supreme Court of Hawaii invalidated the construction permits in 2015, although they were later restored in 2018. Despite this, local opposition has continued to impede construction.

Alternate Site Consideration

• Plan B: The Observatorio del Roque de los Muchachos (ORM) on La Palma in Spain’s Canary Islands is being considered as an alternative site for the TMT.
• India’s Stance: As per statements made in 2020, India prefers moving the project to an alternate site, subject to the availability of necessary permits and procedures.

India’s Role and Contribution

• Major Contributor: India is expected to play a significant role in the TMT project, contributing hardware, instrumentation, and software worth $200 million.
• Mirror Production: Of the 492 required mirrors, India will contribute 83, showcasing its capabilities in precision engineering and technology.

Current Status and Future Prospects

• Ongoing Discussions: Efforts are being made to reach a consensus that respects the concerns of the local people in Hawai’i.
• Progress in Component Development: Despite the delay in construction, significant advancements have been made in developing essential components for the TMT.
• Decision Timeline: A firm decision on the project’s site is anticipated within the next two years, as per Annapurni Subramaniam, director of the Indian Institute of Astrophysics (IIAP).

Introduction

• In a significant scientific breakthrough, Japanese scientists discovered an ultra-high-energy cosmic ray in May 2021, which he named ‘Amaterasu’ after the Japanese sun goddess.

Discovery of Amaterasu

• Event Identification: Dr. Toshihiro Fujii, an astronomer at Osaka Metropolitan University, discovered the cosmic ray named Amaterasu.
• Measurement: Amaterasu had an energy of 240 exa-electron-volt (EeV), an extremely high level.
• Comparison with Man-Made Accelerators: This energy is about 40 million times higher than that of protons accelerated by the Large Hadron Collider (LHC).

Mystery of Amaterasu’s Origin

• Unusual Origin: Amaterasu appears to have originated from an empty part of the universe.
• Dr. Fujii’s Theories: Possible explanations include an unidentified source, interaction with a strong magnetic field, or the need for new physics models.
• Previous Records: The “Oh My God” particle, detected in 1991 with an energy of 320 EeV, remains the most energetic cosmic ray recorded.

Nature and Impact of Cosmic Rays

• Composition: Cosmic rays are streams of energetic particles, including protons and alpha particles, originating from outer space and the sun.
• Interaction with Earth: Most cosmic rays lose their energy in Earth’s atmosphere, preventing harmful high-intensity rays from reaching the surface.
• Historical Significance: Studies of cosmic rays since the 1930s have led to the discovery of many subatomic particles, although their sources and high energy remain a mystery.

Types and Origins of Cosmic Rays

• Galactic Cosmic Rays (GCR): Originating from beyond our solar system, possibly from supernovae.
• Solar Cosmic Rays: Emitted by the sun, primarily in solar flares, consisting mainly of protons.
• Composition Analysis: Studies show a helium-to-hydrogen nuclei mass ratio in cosmic rays similar to the early universe’s composition.

Implications of High-Energy Cosmic Rays

• Ultra-high-energy cosmic Rays (UHECRs): These are extragalactic particles with energies exceeding 1 EeV.
• Limitations in Space Travel: UHECRs with more than 60 EeV energy face suppression due to interaction with cosmic microwave background (CMB) radiation, limiting their travel distance to 50-100 megaparsecs.

Introduction

• A private US company launched a spacecraft carrying NASA instruments, aiming to be the first US spacecraft to land on the Moon in over 50 years.
• This mission is a key component of NASA’s Commercial Lunar Payload Services, integrating private sector capabilities into the Artemis Program.

About Commercial Lunar Payload Services (CLPS) Initiative

• NASA’s collaboration with the private sector under the CLPS initiative involves at least 14 companies contracted to deliver payloads to the Moon.
• This partnership aims to develop a market and technology ecosystem in the private space industry for lunar exploration.
• The mission features the Peregrine lander and the Vulcan rocket, both developed by private US space companies.

Objectives and Payloads

• NASA’s Five Payloads: The Peregrine lander carries five NASA payloads designed for various exploratory tasks, including water detection.
• Laser Retroreflector Array: One payload, designed for precision distance measurements, will be permanently deployed on the Moon’s surface.
• Duration of Activity: Other payloads are expected to remain active for ten days post-landing.

Historical Context: Return to the Moon

• Last US Moon Landing: The last US spacecraft landed on the Moon during the Apollo 17 mission in December 1972.
• Renewed Lunar Interest: The US reignited its lunar exploration efforts in the 1990s and formally committed to return in 2018.
• Artemis Program Goals: NASA’s Artemis Program aims to establish a permanent base on the Moon, facilitating longer human and robotic stays for extensive exploration and scientific research.

Back2Basics: NASA’s Artemis Mission