Lakshya UPPSC PT 2022 – Science & Technology Lecture -2 – Complete One Year Current Affairs

GSAT 7B

In March 2022, the Defence Acquisition Council approved Acceptance of Necessity (AoN) for Capital Acquisition proposals of Armed Forces which includes a long-awaited dedicated military communication satellite GSAT-7B.
GSAT-7B Satellite will enhance operational preparedness of the Armed Forces and boost its communication capabilities. After GSAT-7B, India army will have its dedicated “Eye in the sky”.
Till date, the Indian Army has been dependent on GSAT-7A and other satellites.

Lets Deconstruct

What is GSAT-7 Series?
How are GSAT’s launched?
Other Defence Satellites?

GSAT-7

GSAT-7 (Rukmini)
- The satellite was launched early on 30 August 2013 atop an Ariane 5 ECA rocket from Kourou, French Guiana.
- GSAT-7 is a the multi-band communication satellite named Rukmini which carries the payloads in UHF, C band and Ku band.
- It is the first dedicated military communication satellite built by ISRO to provide services to Indian Navy.
- Rukmini will provide networking capabilities to various Indian Naval assets. During Theater-level Readiness and Operational Exercise (Tropex) in the Bay of Bengal in 2014, Rukmini was able to network about 60 ships and 75 aircraft seamlessly.
Note: Indian Navy has already approached ISRO for launching of the replacement satellite since the lifespan of this satellite is expected to get over in the coming few years. This satellite would be called GSAT-7R and is projected to cost ₹1,589 crores.

Bands for Communication

GSAT-7A

GSAT-7A (Angry Bird)
- ISRO launched a second satellite, GSAT-7A for Indian Air Force on 19 December 2018 on its Geosynchronous Satellite Launch Vehicle (GSLV-F11).
- GSAT-7A allows IAF to interlink different ground radar stations, ground airbase, aircraft to aircraft Real-time Control System, Airborne early warning and control (AWACS) aircraft such as Beriev A-50 Phalcon and DRDO AEW&CS.
- The GSAT-7A, with a mission life of 8 years, is also equipped with the payload of 10 Ku band transponders.
Note: Apart from GSAT, Indian defence forces also uses Electromagnetic Intelligence Gathering Satellite (EMISAT) & RISAT 2BR1 synthetic aperture radar imaging satellite

How do we send a satellite in Space?

Satellite launcher

GSLV (Geosynchronous Satellite launch Vehicle) uses a three stage launching system.

First Stage: Solid stage which provides lift off to the rocket.
Second Stage: Liquid Stage or semi cryogenic stage.
Third Stage: Cryogenic stage.

Note: Initial stage also include strap on boosters which continuously detach after use.

Cryogenic Stage

Rocket engine needs enormous amount of thrust to escape Earth’s gravitational pull.
The fuel used in launch vehicles is Hydrogen and Oxygen (Oxidiser) which produces good thrust but in gaseous form they require a bigger fuel chamber.
Bigger fuel chamber means bigger size & larger weight of rocket which means lower payload eventually..!!
To solve this problem, hydrogen and oxygen in their liquid form or in a cryogenic form are carried. Cryogenic form reduces volume of propellent, increases density & provides more thrust in less burning time.
The engines which used fuel in this form are called Cryogenic engine.

What is Cryogenics?

In physics, cryogenics is the production and behaviour of materials at very low temperatures.
In general, a universal definition of “cryogenics” and “cryogenic” is anything which is below the threshold of 120 K (or –153 °C) so that we can distinguish this from the conventional refrigeration.

PSLV

Polar Satellite Launch Vehicle (PSLV) was the third generation launch vehicle of India after SLV & ASLV.
PSLV was the first Indian launch vehicle to be equipped with liquid stages. Since its first launch in 1994, PSLV emerged as the reliable and versatile workhorse launch vehicle of India.
Between 1994-2017, PSLV launched 39 consecutively successful missions. PSLV evolved through different variants like PSLV-CA, PSLV-DL, PSLV-QL & PSLV-XL. PSLV-XL had a Payload capability of 1523 Kg till 600km.

GSLV

Geosynchronous Satellite Launch Vehicle is the largest launch vehicle in India.
It is a fourth generation launch vehicle with indigenously developed cryogenic Upper Stage (CUS). It has evolved through variants like Mark I, II & III (Still in testing).
Infact, GSLV Mk III has been chosen to launch Chandrayaan-3.
GSLV Mk III is designed to carry 4000 kg payload into Geosynchronous or about 10000 kg to Low Earth Orbit (LEO).

Chandrayaan – 3

Recently, ISRO gave an insight into its preparation of its stated plans to execute the Chandrayaan-3 mission in August 2022.
The Chandrayaan-3 mission is a follow-up of Chandrayaan-2 of July 2019, which aimed to land a rover on the lunar South Pole.

Chandrayaan

Chandrayaan-1 was India’s first mission to the moon. Chandrayaan-1 was launched by India’s Polar Satellite launch Vehicle, PSLV-C11 on October 22, 2008 from Satish Dhawan Space Centre SHAR, Sriharikota, India. The spacecraft made more than 3400 orbits around the moon. Chandrayaan-1 was operational for 312 days till August 29, 2009.
Chandrayaan-2 is a follow-on mission to the Chandrayaan-1 Mission launched on 22 July 2019. Chandryaan-2 comprised of an Orbiter, Lander (Vikram) and Rover (Pragyaan). The Orbiter would watch the moon from a 100-km orbit. It was sent aboard the country’s most powerful geosynchronous launch vehicle, the GSLV-Mk 3.
The Lander Vikram, instead of a controlled landing, ended up crash-landing and prevented rover Pragyaan from successfully travelling on the surface of the moon.

Chandrayaan – 3

The Chandrayaan 3 mission will launch from the Satish Dhawan Space Center atop a Geosynchronous Satellite Launch Vehicle Mark III rocket.
The Chandrayaan-3 mission is a follow-up of Chandrayaan-2 of July 2019. Chandrayaan 3 is aiming for the same landing site in the moon’s south polar region that Vikram targeted in 2019.
If all goes well, India would become the fourth country to successfully soft-land on the moon, after the United States, Russia and China, although none of those countries has yet landed at the ice-rich south pole.

Why South Pole?

PYQs

With reference to India’s satellite launch vehicles, consider the following statements: (UPSC CSE Prelims 2018)
(1) PSLVs launch satellites useful for Earth resources monitoring whereas GSLVs are designed mainly to launch communication satellites.
(2) Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth.
(3) GSLV Mk III is a four-staged launch vehicle with the first and third stages using solid rocket motors; and the second and fourth stages using liquid rocket engines.
Which of the statements given above is/are correct.?
(a) 1 only
(b) 2 and 3
(c) 1 and 2
(d) 3 only

PYQs

In which of the following activities are Indian Remote Sensing (IRS) satellites used? (UPSC CSE 2015)
(1) Assessment of crop productivity
(2) Locating ground water resources
(3) Mineral exploration
(4) Telecommunications
(5) Traffic studies
Select the correct answer using the code given below

a) 1, 2 and 3 only
b) 4 and 5 only
c) 1 and 2 only
d) 1, 2, 3, 4 and 5

PYQs

With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements :
(1) IRNSS has three satellites in geostationary and four satellites in geosynchronous orbits.
(2) IRNSS covers entire India and about 5500 sq. km beyond its borders.
(3) India will have its own satellite navigation system with full global coverage by the middle of 2019.
Which of the statements given above is/are correct?
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) None