Subject: Space Technology

Why in the news?

• The Bengaluru-based Indian Institute of Astrophysics (IIA) captured the moon passing in front of Antares, a bright red star.
• Moon occasionally occults bright stars such as Antares and planets as it orbits the Earth once a month.

About Antares (Jyeshtha)

• Antares is a red supergiant star also called ‘Alpha Scorpii,’ located in the constellation of Scorpius.
• It is visible in the southern sky during the summer months in the northern hemisphere.
• It is often referred to as the “heart of the scorpion” due to its location within the Scorpius constellation and its striking red color.
• It is a massive star, with a diameter estimated to be around 700 times that of the Sun.
• It has a relatively low surface temperature compared to other stars, which gives it its distinctive red color.
• The distance to Antares from Earth is approximately 550 light-years, making it one of the closest red supergiant stars to our solar system.

What is Occultation? An occultation is a total or a partial cut-off of the light of a celestial body due to its passage behind another body. The finest example of an occultation is the solar eclipse. Strictly speaking, it is not an eclipse, but a lunar occultation of the sun.

 

PYQ: [2012] A person stood alone in a desert on a dark night and wanted to reach his village, which was situated 5 km East of the point where he was standing. He had no instruments to find the direction, but he located the pole-star. The most convenient way now to reach his village is to walk in the _______. (a) Direction facing the pole-star (b) Direction opposite to the pole-star (c) Direction keeping the pole-star to his left (d) Direction keeping the pole-star to his right

Why in the news?

NASA has launched its Advanced Composite Solar Sail System (ACS3) spacecraft that uses sunlight for propulsion from New Zealand into space.

About Advanced Composite Solar Sail System (ACS3) Project

• The spacecraft is slated to orbit 1,000 kilometers above Earth, deploying an 80-square-meter solar sail approximately 25 minutes after liftoff.
• It harnesses sunlight as a renewable propulsion source, marking a novel advancement in space exploration.
• It uses a compact CubeSat, similar in size to an oven, which facilitates propulsion by capturing solar particle energy.
• Operational Phases:
• The initial flight phase spans two months and involves subsystems checkout and solar sail deployment.
• A series of pointing maneuvers will showcase orbit raising and lowering, validating the effectiveness of sunlight pressure on the sail.

The Technology Behind: Solar Sailing

• Solar sails typically consist of lightweight, reflective materials such as Mylar or aluminized Kapton, which are deployed in space to capture sunlight.
• The sail is often configured as a large, thin membrane with a large surface area to maximize the amount of sunlight it can intercept.
• When sunlight reflects off a shiny solar sail, some of its momentum is transferred, giving the sail a small push.

Solar sailing offers several advantages over traditional propulsion methods, including:

1. Efficiency: Solar sailing does not require onboard fuel, making it a highly efficient and sustainable propulsion method for long-duration missions.
2. Continuous thrust: Unlike chemical rockets, which provide brief bursts of acceleration, solar sails can provide continuous thrust as long as they are exposed to sunlight.
3. Maneuverability: Solar sails can change their trajectory by adjusting the orientation of the sail relative to the direction of incoming sunlight. This allows for precise navigation and maneuvering in space.
4. Interstellar travel: Solar sailing has the potential to enable interstellar missions by gradually accelerating spacecraft to very high velocities over time, allowing them to explore distant star systems.

 

PYQ: [2016] What is ‘Greased Lightning-10 (GL-10)’, recently in the news? (a) Electric plane tested by NASA (b) Solar-powered two-seater aircraft designed by Japan (c) Space observatory launched by China (d) Reusable rocket designed by ISRO

Why in the news?

India and the US have decided to reactivate the Indian Ocean Observing System (IndOOS).

What is IndOOS?

• Established in 2006, the Indian Ocean Observing System (IndOOS) comprises moored buoys strategically placed across the Indian Ocean.
• It consists of a network of 36 moored buoys in the high seas to collect high-resolution ocean and atmospheric data for weather forecasts.
• These buoys measure various parameters like seawater temperature, salinity, ocean currents, atmospheric humidity, and wind speed.
• IndOOS originally focused on understanding and predicting the monsoon.
• It now aids in climate modelling under changing climatic conditions and predicts extreme weather events such as floods, droughts, and cyclones.

Objectives of IndOOS include:

1. The primary objective of IndOOS is to provide continuous and high-quality oceanographic and meteorological data to support informed decision-making and improve scientific understanding of weather and climate.
2. It aims to foster partnerships among Indian Ocean countries and beyond to enhance long-term monitoring and forecasting capabilities.

Need for IndOOS

• The Indian Ocean region, home to nearly one-third of the global population, faces significant vulnerabilities due to climate change and extreme weather events.
• Fisheries and rain-dependent agriculture in these regions are heavily influenced by the monsoon, making accurate weather forecasts crucial for mitigating potential damage to crops and livelihoods.
• The Indian Ocean’s influence extends beyond its boundaries, redistributing heat across the planet and modulating the climate in the Pacific, North Atlantic and Mediterranean Sea.

Observing Networks under IndOOS

• The framework for IndOOS comprises five observing networks:

1. Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA)
2. Profiling floats (part of the global Argo array)
3. Surface drifters (Global Drifter Program, GDP)
4. Repeat temperature lines (eXpendable Bathy Thermograph (XBT) network)
5. Tide gauges

• These networks are complemented by satellite observations of surface wind, sea level, temperature, salinity, rainfall, and ocean color.

Partnerships and Support:

• IndOOS originated from discussions among scientists during the First International Conference on the Ocean Observing System for Climate (OceanObs) in 1999.
• An implementation plan for IndOOS was developed by the Indian Ocean Panel, established under the Climate and Ocean Variability, Predictability, and Change (CLIVAR) and Intergovernmental Oceanographic Commission – Global Ocean Observing System (IOC-GOOS) programs.

Why in the news?

• The White House directed NASA to establish a time standard for the Moon, named Coordinated Lunar Time (LTC) by the end of 2026.
• This move aims to facilitate coordination among international bodies and private companies operating on the lunar surface.

Timekeeping on the Moon

• The Moon has its own day and night cycle, which lasts about 29.5 Earth days.
• Currently, the time on the Moon is measured using Coordinated Universal Time (UTC), which is the same timekeeping system used on the Earth.
• However, because the Moon’s day is much longer than Earth’s day, it would be difficult to use UTC for day-to-day activities on the Moon.

Coordinated Universal Time (UTC) UTC is a time standard introduced on January 1, 1960. It is based on International Atomic Time (TAI), which is maintained by atomic clocks around the world. It is the primary time standard used by many countries, international organizations, and scientific research institutions. It is expressed as a 24-hour clock and is used to indicate the time offset from Coordinated Universal Time (UTC+0). Time zones are defined as an offset from UTC, with some time zones being ahead of UTC (UTC+1, UTC+2, etc.) and others being behind UTC (UTC-1, UTC-2, etc.). It is adjusted periodically to account for changes in the Earth’s rotation, which can cause variations in the length of a day. These adjustments are made through the addition of leap seconds to UTC, which help to keep the time standard synchronized with the Earth’s rotation.

Need for a Lunar Time Standard

1. Earth’s Time Standard:

• Earth’s time standard is primarily based on Coordinated Universal Time (UTC), set by the International Bureau of Weights and Measures in Paris, France.
• UTC is determined by a weighted average of over 400 atomic clocks worldwide, providing a universally agreed-upon standard for time measurement.

2. Challenges with Earth’s Time Standard on the Moon:

• Time on the Moon differs from Earth due to factors like gravity and the Moon’s rotation.
• Time on the Moon ticks slightly faster due to lower gravity (about 56 microseconds every day) as per Einstein’s Theory of General Relativity.

Establishing a Lunar Time Standard:

1. Technical Considerations:

• LTC cannot be based on UTC due to the time differences between Earth and the Moon.
• Current lunar missions operate on independent timescales linked to UTC, but this approach becomes challenging with multiple space crafts on the Moon.

2. Deployment of Atomic Clocks:

• Like on Earth, atomic clocks can be deployed on the lunar surface to establish a time standard.
• A 2023 report suggests placing at least three atomic clocks on the Moon’s surface, accounting for variations in lunar rotation and local gravity.

3. Synthesizing Time Measurements:

• Atomic clocks placed at different lunar locations will tick at the Moon’s natural pace.
• Output from these clocks will be combined using algorithms to generate a unified time standard for the Moon, tied back to UTC for Earth operations.

Earth’s Latitudinal Variations on Time On Earth, atomic clocks placed at different latitudes experience variations in time due to differences in rotational speed of Earth. Earth rotates faster at the Equator compared to the poles, resulting in different time measurements.

Benefits offered by Lunar Time

• Having a lunar time zone would also make it easier for scientists and researchers to conduct experiments and collect data on the Moon.
• It would also help to prevent confusion and errors that could arise from using different timekeeping systems on Earth and the Moon.

PYQ: [2015] Tides occur in the oceans and seas due to which among the following? 1. The gravitational force of the Sun 2. The gravitational force of the Moon 3. The centrifugal force of the Earth Select the correct option using the code given below: (a) 1 Only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Why in the news?

• The Indian Space Research Organisation (ISRO) has said its PSLV-C58/XPoSat mission has practically left zero debris in earth’s orbit.

About PSLV Orbital Experimental Module-3 (POEM-3)

• Launched on January 1, 2024, POEM-3 utilized the spent PS4 stage of the PSLV-C58 vehicle, which initially launched XPoSat.
• It is a three-axis-altitude controlled platform with power generation and tele-command & telemetry capabilities, for supporting Payloads.
• The XPoSat mission aimed to leave no debris in space, demonstrating ISRO’s commitment to responsible space practices.
• Upon deployment into its orbit at 650 km, POEM-3 was maneuvered to a 350 km circular orbit to minimize orbit decay time after the experiment’s completion.
• After completing 400 orbits, POEM-3 re-entered Earth’s atmosphere after 73 days in space.

Significance of this achievement

• With the rise in the number of satellites in orbit around the earth, space debris has become a pressing issue.
• Space debris in the low earth orbit (LEO) mainly comprises pieces of spacecraft, rockets, and defunct satellites, and the fragments of objects that have deteriorated explosively as a result of anti-satellite missile tests.
• This debris often flies around at high speeds of up to 27,000 kilometres per hour.
• Due to their sheer volume and momentum, they pose a risk to several space assets.

Threats posed by Space Debris

• Space debris also leads to two major risks:

1. It creates unusable regions of the orbit due to excessive debris, and
2. Leads to the ‘Kessler syndrome’ – creation of more debris due to cascading collisions resulting from one collision.

Various Initiatives to mitigate the Space Debris Issue

	Description
Project NETRA	ISRO initiative for early warning system in space to detect debris and hazards to the Indian satellites. It can spot, track and catalogue objects as small as 10 cm, up to a range of 3,400 km and equal to a space orbit of around 2,000 km.
Space Debris Mitigation Guidelines	Established in 2002 by the Inter-Agency Space Debris Coordination Committee (IADC) and endorsed by the United Nations in 2007.
Zero Debris Charter by ESA	Adopted by the European Space Agency (ESA) with the goal of achieving zero space debris by 2030.
NASA’s Orbital Debris Program	NASA’s initiative since 1979, focusing on reducing orbital debris creation, tracking existing debris, and exploring debris removal technologies.
Space Force Tracking System	Implemented by the U.S. Space Force to monitor space debris and assess collision risks in low Earth orbit (LEO).
Chinese Debris Removal Initiatives	China’s efforts include deploying spacecraft for debris removal with innovative technologies like solar sails.
Japanese CRD2 Demonstration	Partnership between Japan’s Aerospace Exploration Agency (JAXA) and Astroscale to develop debris removal technologies.

 

Practice MCQ: ISRO’s PSLV Orbital Experimental Module-3 (POEM-3) recently re-entered Earth’s Orbit. What is so significant about this re-entry? (a) It practically left zero debris in earth’s orbit. (b) It facilitated groundbreaking research on the effects of microgravity on biological organisms. (c) It paved the way for the development of reusable spacecraft technology, reducing the cost of future space missions. (d) None of these.

Why in the news?

• The “Mother of Dragons” comet, officially named Comet 12P/Pons-Brooks, is making a rare appearance in the Northern Hemisphere skies.
• This Halley-type comet, completing its orbit every 71 years, has emerged marking its first sighting since 1954.

What is a Comet?   A comet is a celestial object composed primarily of ice, dust, and rocky particles that orbit the Sun in elongated, elliptical paths. These icy bodies originate from the outer regions of the solar system, specifically from two regions: the Kuiper Belt and the Oort Cloud. Comets are often referred to as “dirty snowballs” or “icy dirtballs” due to their composition. Halley’s Comet is a short-period comet visible from Earth every 75–79 years. It was last seen in Earth’s skies in 1986 and was met in space by an international fleet of spacecraft. It will return in 2061 on its regular journey around the Sun.

 

About Mother of Dragons Comet

• It is named by the European Space Agency (ESA).
• The comet’s name is inspired by its link to the annual “kappa-Draconids” meteor shower, active from November 29 to December 13 each year.
• It has a width of 17 km. the comet features an elliptical orbit adorned with a mysterious spiral of luminous light enveloping its icy nucleus.
• It is comprised of ice, dust, rock, and diatomic carbon molecules.
• It dissipates a radiant emerald hue when illuminated by the sun, captivating observers with its bright green appearance.

Display Features of the Comet

• Renowned for its cryovolcanic eruptions, the comet periodically ejects material from its icy core into space, resulting in breath-taking luminosity.
• Its most recent eruption in July 2023, after 69 years, earned it the moniker “devil comet” due to its dramatic outburst, resembling horns likely caused by internal features.

PYQ: 2014: What is a coma, in the content of astronomy? (a) Bright half of material on the comet (b) Long tail of dust (c) Two asteroids orbiting each other (d) Two planets orbiting each other   Practice MCQ: With reference to the “Mother of Dragons” Comet, consider the following statements: 1.    It is named by the NASA. 2.    It is comprised of ice, dust, rock, and diatomic carbon molecules. 3.    It makes appearances after every 10 years. How many of the above statements is/are correct? (a) One (b) Two (c) Three (d) None