India’s first Sun observatory launched

GS Paper - 3 (Space Technology)

The Indian Space Research Organisation (ISRO) launched Aditya L-1, its first space-based mission to study the Sun, from the Satish Dhawan Space Centre in Sriharikota on 2 September 2023. The lift-off took place barely 10 days after ISRO became the first space agency to soft-land a spacecraft near the Moon’s South Pole.

How did the Aditya L-1 go into space?

• The solar probe was carried into space by the Polar Satellite Launch Vehicle (PSLV) in ‘XL’ configuration. PSLV is one of the most reliable and versatile workhorse rockets of ISRO.
• Previous missions like Chandrayaan-1 in 2008 and Mangalyaan in 2013 were also launched using PSLV. The rocket is most powerful in the ‘XL’ configuration as it is equipped with six extended strap-on boosters — they are larger than the boosters of other configurations and, therefore, can carry heavier payloads.
• PSLV-XL can lift 1,750 kg of payloads to the sun-synchronous polar orbit (spacecraft here are synchronised to always be in the same ‘fixed’ position relative to the Sun), and much more — 3,800 kg — to a lower Earth orbit (normally located at an altitude of less than 1,000 km but could be as low as 160 km above the planet). As Aditya L-1 weighs 1,472 kg, it was launched aboard PSLV.
• Notably, Chandrayaan-3 took off aboard LVM3, the most powerful rocket of ISRO, because it was more than two times heavier than the solar probe.

What is the Aditya L-1 mission?

• The PSLV will initially place the Aditya L-1 in a lower Earth orbit. Subsequently, the orbit as well as the velocity of the spacecraft around the Earth will be increased using onboard propulsion till it is slingshot towards the Sun.
• The spacecraft will finally be stationed in a halo orbit around the Lagrange point 1 (L1) of the Sun-Earth system (more on this later), which is about 1.5 million km from the Earth.
• Named after the rising Sun, the Aditya L-1 will cover its journey to the L1 point in about four months. The spacecraft will carry seven payloads to observe solar activities for five years.

What are the objectives of the Aditya L-1?

• The mission’s main objective is to expand our knowledge of the Sun, and how its radiation, heat, flow of particles, and magnetic fields affect us.
• To study the upper atmospheric layers of the Sun called chromosphere and corona. While the corona is the outermost layer, the chromosphere is just below it.
• To examine coronal mass ejections (CMEs), which are large expulsions of plasma and magnetic fields from the Sun’s corona
• To analyse the corona’s magnetic field and the driver of the space weather
• To understand why the Sun’s not-so-bright corona is a million degree Celsius hot when the temperature on the surface of the Sun is just about 5,500 degree Celsius
• To help scientists know the reasons behind the acceleration of particles on the Sun, which leads to the solar wind — the constant flow of particles from the Sun.

What are the payloads?

• There are essentially seven payloads on the Aditya L-1. The main one is the Visible Emission Line Coronagraph (VLEC) to study the solar corona from the lowermost part upwards.
• The Solar Ultraviolet Imaging Telescope (SUIT) will capture the UV image of the solar photosphere and chromosphere. It will examine the variation in light energy emitted.
• Meanwhile, the Solar Low Energy X-ray Spectrometer (SoLEXS) and High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) will analyse X-ray flares.
• The Aditya Solar wind Particle Experiment (ASPEX) and Plasma Analyser Package for Aditya (PAPA) have been built to study the solar wind and energetic ions.

What are the Lagrange points?

• There are five Lagrange points, L1 to L5, between any two-celestial body systems. At these positions, the gravitational pull of the celestial bodies equals the centripetal force required to keep a smaller third body in orbit. In simpler words, the forces acting on the third body cancel each other out.
• The points can be used as ‘parking spots’ for spacecraft in space to remain in a fixed position with minimal fuel consumption.
• They have been named after Italian-French mathematician Joseph-Louis Lagrange (1736-1813), who was the first one to find the positions.
• So, between the Earth and the Sun, a satellite can occupy any of five Lagrangian points. “Of the five Lagrange points, three are unstable and two are stable.
• The unstable Lagrange points – labelled L1, L2, and L3 – lie along the line connecting the two large masses. The stable Lagrange points – labelled L4 and L5 – form the apex of two equilateral triangles.
• The L4 and L5 are also called Trojan points and celestial bodies like asteroids are found here.

Largest indigenously developed N-plant starts ops

GS Paper - 3 (Energy)

The third unit of the indigenously developed 700-megawatt electric (MWe) nuclear power reactor at the Kakrapar Atomic Power Project (KAPP3) in Gujarat has commenced operations at full capacity. This comes a little over three years since the unit achieved its ‘first criticality’ – a technical term that signifies the initiation of a controlled, but sustained nuclear fission reaction – in July 2020. On 30 June this year, the unit had started commercial operations.

More about the News

• In India’s civilian nuclear programme, this is seen as a landmark event, given that KAPP-3 is the country’s first 700 MWe unit and the biggest indigenously developed variant of the Pressurised Heavy Water Reactor (PHWR).
• The PHWRs, which use natural uranium as fuel and heavy water as moderator, constitute the mainstay of India’s nuclear power fleet.
• Till now, the biggest reactor of indigenous design was the 540 MWe PHWR, two of which have been deployed in Tarapur, Maharashtra.
• For India, the operationalisation of its first 700MWe reactor is a significant scale up in technology, both in terms of the optimisation of its PHWR design — the new 700MWe unit addresses the excess thermal margins and also marks an improvement in the economies-of-scale, without significant design changes to the 540 MWe reactor.

Flashback

• As India works to ramp up its existing nuclear power capacity of 7,480 MWe to 22,480 MWe by 2031, the 700MWe capacity would constitute the biggest component of this expansion plan. Currently, nuclear power capacity constitutes around 2 per cent of the total installed capacity of 4,17,668 MW (May 31).
• Significantly, as India’s civilian nuclear sector gears up to its next frontier — building a 900 MWe Pressurised Water Reactors (PWRs) of indigenous design – the experience of executing the larger 700MWe reactor design would come in handy, especially with respect to the improved capability of making large-size pressure vessels, alongside India’s own isotope enrichment plants being developed to supply a part of the required enriched uranium fuel to power these new generation reactors over the next decade or so, according to DAE officials.
• The first ‘pour of concrete’ for laying the foundation of KAPP-3 happened in November 2010 and this unit was originally expected to be commissioned in 2015.

Navy's stealth frigate Mahendragiri launched

GS Paper - 3 (Defence)

The seventh stealth frigate, under the Indian Navy's Project 17 A, Mahendragiri, was launched on 1 September 2023. Built at Mazagon Dock Shipbuilders Ltd (MDL), the vessel was developed as part of the push towards the Aatmnirbhar Bharat idea.

More about the frigate

• Mahendragiri, a technologically advanced warship stands as a symbol of India's determination to embrace its rich naval heritage, while propelling itself towards a future of indigenous defence capabilities.
• Mahendragiri, named after a mountain peak in Eastern Ghats located in the state of Odisha, is the seventh ship of the Project 17A Frigates.
• These warships are follow-ons of the Project 17 Class Frigates (Shivalik Class), with improved stealth features, advanced weapons and sensors, and platform management systems.