Space Exploration

 Lecture 12 Space Exploration(Part-1) 

Space and Earth Orbits

Karman line- Boundary separating Earth's atmosphere and outer space. It lies above 100 Km of mean sea level. 

Orbit- Curved trajectory of an object around a star or planet. 

Earth orbits

1. Low Earth orbit (LEO)- Altitudes up to 2,000 km
2. Medium Earth orbit(MEO)- Altitude from 2,000 km to below geosynchronous orbit 
3. Geosynchronous orbit(GSO)- Orbit with an orbital period of Earth's rotation i.e. 23 hours 56 minutes and 4 seconds(one sidereal day). 
4. Geostationary orbit(GEO)- A circular geosynchronous orbit in the plane of the Earth's equator with an altitude of approximately 36000 km. The object placed in geostationary orbit maintains the same position relative to the Earth's surface.
5. Geostationary Transfer orbit(GTO)- Transfer orbits are a special kind of transit orbit used to send object from one orbit to another. 
6. High Earth orbit(HEO)- Altitudes above 36,000 Km
7. Polar orbit- Satellites in polar orbits travel from north to south rather than from west to east, passing roughly over Earth's poles. Polar orbits are LEO with altitude range between 200 to 1000 km.
8. Sun synchronous orbit- A kind of polar orbit. Satellites in SSO travel over the polar regions and are synchronous with the Sun.

Lagrange points- Point where the gravitational fields of Earth and the Sun cancel out each other in such a way that spacecraft orbiting at that point remain stable. 

Space Exploration

• 1957- USSR sent the Sputnik 1 satellite
• 1959- Luna 2 of USSR became the first probe to land on moon
• 1961- Yuri Gagarin(USSR) became the first person to visit space via Vostok 1 spaceflight
• 1965- First spacewalk by Alexei Leonov(USSR) under Voskhod 2 mission. 
• 1969- Neil Armstrong(USA) became the first human landed on moon under Apollo 11 mission. 
• 1970- Lunar soils were brought back to Earth by Luna 16(USSR) and Apollo 13(US) 
• 1971- Salyut 1(USSR) became the world's first space station. 
• 1986- Mir(USSR) became the first modular space station assembled in space to orbit low earth orbit
• 1989- Galileo(NASA) was launched to study Jupiter. 
• 1997- Cassini Huygens(NASA+ ESA) was launched. Cassini- Saturn orbiter, Huygens- Titan lander
• 1998- International Space Station(ISS) assembled by the collaboration of five space agencies- NASA(US), Roscosmos(Russia), ESA(Europe), JAXA(Japan), and CSA(Canada) to orbit in low earth orbit
• 2003- Hayabusa a robotic spacecraft was developed by JAXA to return a sample of material from an asteroid named 25143 Itokawa to Earth.
• 2004- MESSENGER mission(operated 2011-2015) was launched by NASA to study mercury
• 2011- Juno(NASA) was launched to study Jupiter
• 2012- Voyager 1(NASA) became the first spacecraft to left solar system and reach interstellar space. 
• 2018- Parker Solar Probe launched by NASA to study corona of the sun
• 2019- China's Chang-e 4 was the first space object to land far side of moon
• 2024- China's Chang-e 6 was the first space object to bring lunar soil of far side of moon

Space Exploration by ISRO

• 1962- Indian National Committee for Space Research(INCOSPAR) formed by the Department of Atomic Energy and Thumba Equatorial Rocket Launching Station(TERLS) was established at Tumba, Thiruvananthapuram(Kerala). 
• 1963- First sounding rocket launched from TERLS
• 1969- Indian Space Research Organisation(ISRO) formed under Department of Atomic Energy 
• 1972- Space Commission and Department of Space was established(ISRO brought under DOS). 
• 1975- First Indian Satellite Aryabhata launched from USSR
• 1979- Bhaskara I satellite launched from USSR. Satellite launch vehicle(SLV-3) test failed.
• 1980- Second Experimental launch of SLV-3(Succeeded), Rohini satellite- first satellite successfully launched by India. 
• 1984- Rakesh Sharma became the first Indian to go into space under Indo Soviet manned space mission. 
• 1987- First developmental launch of Augumented Satellite Launch Vehicle(ASLV- failed). 
• 1993- Developmental launch of Polar Satellite Launch Vehicle(PSLV- failed) 
• 1994- Second developmental launch of PSLV succeeded
• 2001- The first developmental launch of Geosynchronous Satellite Launch Vehicle(GSLV- failed) 
• 2003- GSLV successfully launched the satellite
• 2008- PSLV successfully launches CHANDRAYAAN-1 from Sriharikota(October 22, 2008).
• 2013- Mars Orbiter Mission(Mangalyaan), first interplanetary mission of ISRO launched by PSLV. ISRO became the fourth space agency to successfully launch a spacecraft into Mars orbit and first to successfully launch Mars orbiter in maiden flight. 
• 2019- Chandrayaan 2 mission with a lander named Vikram and a rover named Pragyan. Launched by GSLV. The soft landing of Vikram lander failed. 
• 2023- Chandrayaan 3 mission -It made ISRO the first space agency to soft-land on the lunar surface's south pole. 
• 2023- Aditya L1 mission launched using PSLV to orbit sun at Lagrange point L1. 

Crashed site of chandrayaan 2- Tiranga

Landing site of chandrayaan 3- Shiv Shakti

23 August- National Space Day to celebrate the successful landing of Vikram lander(Chandrayaan 3 Mission) 

Launch Vehicle Developed by ISRO

SLV(Satellite Launch Vehicle)- India's first experimental satellite launch vehicle.

It was a four-stage(all solid) vehicle with launch capacity of 40 kg payloads into Low Earth Orbit (LEO). It successfully launched rohini satellite into low earth orbit. 

ASLV(Augmented Satellite Launch Vehicle)- SLV 3 was followed by ASLV that remain in operation until the 1990s and retired after the launch of PSLV. It was a five-stage(all solid) vehicle with payload capacity of 150 kg(400 km circular orbits) .

Active launch vehicle of ISRO

Reusable launch vehicle- Parts that can be recovered and reflown, while carrying payloads from the surface to outer space. Additional avionics and propellant, making them heavier than their expendable counterparts but reuseability reduces launch cost significantly. 

Hybrid Rocket System- Oxidizer(Liquid State) + Fuel(Solid State) 

RHUMI-1 - India's first reusable hybrid rocket developed by Space Zone India(Private company) 

Space Project of ISRO

NavIC- Indian Regional Navigation Satellite System(IRNSS) also know as NavIC (Navigation with Indian Constellation) is a regional satellite navigation system of 7 satellite(3 Geostationary + 4 Geosynchronous satellite). It covers India and a region extending 1,500 km around it. 

NISAR- NASA ISRO Synthetic Aperture Radar(NISAR) mission is a joint project between NASA and ISRO to co-develop and launch a dual frequency synthetic aperture radar on an Earth observation satellite in sun synchronous orbit. L band radar by NASA and S band radar by ISRO. 

GAGANYAN- Human spaceflight mission capable of launching crew of 3 members to an orbit of 400 km for a 3 days mission and bring them back safely to earth, by landing in Indian sea waters. The astronauts chosen for this mission are from the Indian Air Force named Prashanth Balakrishnan Nair, Ajit Krishnan, Angad Pratap and Shubhanshu Shukla. All 4 took training in Russia. 

Vyommitra(space friend)- Female humanoid that will be sent into space prior to human spaceflight of Gaganyan mission

Axiom Mission(NASA)- 4 astronauts will be sent to ISS including 2 Indian named Shubhanshu Shukla and Prasanth Balakrishnan Nair(both are part of India's Gaganyaan Mission) 

Project NETRA(Network for space object Tracking and Analysis)- An early warning system in space to detect debris and other hazards to Indian satellites.

BHUVAN- Indian web based utility which allows users to explore a set of geographic content prepared by the Indian Space Research Organisation. 

Mission Shakti- Joint programme of the DRDO and ISRO in which an anti-satellite weapon was launched and targeted an Indian satellite(decommissioned). Mission Shakti was carried out from DRDO’s testing range in Odisha’s Balasore. 

India became the 4th country to have such capability after US, Russia and China.

Table of Contents                                                 Lecture 13