What’s ISRO Up To? A Listicle

A view of ISRO’s GSLV-Mk III D2 mission carrying the GSAT 29 communication satellite, in Sriharikota, November 2018. Credit: PTI

The Indian Space Research Organisation (ISRO) released its 2021-2022 annual report on April 27. Here are some salient points from the report.

Past and future missions

Major science missions

Operating

1. AstroSat – a multi-frequency mission launched in September 2015, has completed seven years of operations, currently serving 1,530 users in 48 countries, has resulted in more than 600 papers and some important discoveries (including the characteristics of thermonuclear bursts on neutron stars).
2. Mars Orbiter Mission – ISRO’s first mission to another planet, launched in November 2013.
3. Chandrayaan 2 orbiter – launched in July 2019, second ISRO mission to the Moon; the lander crashed on the lunar surface instead of gently landing and was destroyed together with the rover; the lunar orbiter’s instruments have been studying the lunar surface as well as solar emissions.

Upcoming

1. Chandrayaan 3 – ISRO’s third mission to the Moon to demonstrate what Chandrayaan 2 couldn’t achieve (the lunar lander and rover technologies) with similar payloads; mission listed as being in “advanced stage of realisation”, expected launch in 2023
2. Aditya L1 – mission to study the Sun from the first Sun-Earth Lagrange point in space (1.5 million km away), seven instruments onboard will study the three layers of the Sun’s atmosphere and their effects on space weather, expected launch around October 2022.
3. XPoSat – space satellite designed to study X-ray emissions from objects in outer space, contains two instruments to record photons of two energy ranges (0.8-15 keV and 8-30 keV), expected launch later in 2022.

Gaganyaan – human spaceflight

1. First of two uncrewed test flights expected in mid-2022, in 170 x 408 km orbit.
2. GSLV Mk III structure redesigned to accommodate human occupants and associated safety requires.
3. Solid motor segments required for the two S200 strap-on boosters (which use solid fuel) ready ahead of testing for human spaceflight.
4. Three tests of second stage, powered by two Vikas engines (which use liquid fuel), completed.
5. Four short-duration and one long-duration test of the third stage, powered by the CE20 cryogenic engine, completed.

(Note: Major parts of a rocket that will carry humans for the first time will have to be tested again even if they have been tested before for non-human payloads.)

According to the report, the uprighting system has been tested for two configurations – 6º from the vertical and 170º from the vertical; the latter implies that the crew module will be stable even in a sideways configuration after it has descended into the water.

Note on budget:

Based on the programmatic requirements, the BE allocation was Rs 1,900 crore for the FY 2021-2022. However, [COVID-related] lockdown, disruptions in supply chain and provision for delivery date extension have resulted in the delay in delivery of hardware/components. Based on RE, the allocation was revised as Rs 1,400 crore. However, there is no impact with respect to realising the systems for meeting first unmanned mission… Based on third quarter review, RRE was defined as Rs 1,100 crore for FY 2021-2022. Expenditure as on December 31, 2021 is Rs 730.0 crore.

Other launch vehicles/technologies

1. Hypersonic Air-Breathing Vehicle – a vehicle with a scramjet engine with an objective to “demonstrate the accelerating flight of a hypersonic vehicle with scramjet engine power from Mach 6 to Mach 7 in 250 seconds at constant dynamic pressure”, with eventual use in a two-stage rocket, ignition system fuel injection struts ready, tests of thermal protection system underway.
2. Semicryogenic propulsion – ISRO is developing a 2,000-kN semi-cryogenic engine that will use liquid oxygen and Isrosene (propellant-grade kerosene) as propellants, such an engine will be required to develop heavy-lift launch vehicles (ability to lift at least 20 tonnes into low-Earth orbit), propellant tanks are ready and structural qualification tests are underway.
3. Reusable Launch Vehicle – design resembling the now-retired NASA Space Shuttle, technology demonstration test awaited in which the vehicle will be carried to an altitude of 5 km by a helicopter, from where the vehicle will descend and land autonomously in an air field, some tests have been performed to check landing gear, navigation and guidance controls.
4. Small Satellite Launch Vehicle – first static test conducted in March 2021 failed, second static test planned in 2022, first developmental flight expected in May 2022 and two more such flights later in the year.

10 major Earth-observation satellites in service

1. Resourcesat 1 – an advanced remote-sensing satellite launched in 2003, wasn’t listed as ‘in service’ in last year’s annual report but has been listed this year, reason for discrepancy not clear.
2. Resourcesat 2 and 2A – former a follow-up mission to Resourcesat 1 with similar features but advanced capability, also included an instrument from Canada to track ships on the high seas on the very-high frequency (VHF) band; latter launched in December 2016 as a follow-up.
3. Cartosat 2 – a steerable cartographic satellite launched in 2007. While the annual report lists it as ‘in service’, ISRO started deorbiting the satellite from March 2020, in line with the UN Office for Outer Space’s guidelines to mitigate orbital debris. The satellite is expected to descend slowly towards the ground and burn up in the next decade.
4. Cartosat 2A – a cartographic satellite with similar features as Carotsat 2, launched in April 2008 and eventually placed in a Sun-synchronous orbit.
5. RISAT 2, 2B and 2B-R1 – first: a satellite that uses a synthetic aperture radar to map features on the ground in day and night and in all seasons, useful for disaster management, launched in April 2009; second and third: follow-ups launched in May and December 2019.
6. Cartosat 2B and 3 – former launched in July 2012, a cartographic satellite with similar features as Cartosat 2A but is more steerable and can provide depth data as well (i.e. 3D ‘vision’); latter launched in November 2019, is more agile in orbit.
7. Megha-Tropiques – launched in October 2011, joitnly built by ISRO and its French counterpart, studied atmospheric convection and moisture over the tropics, not clear why ISRO has listed it as ‘in service’ since ISRO itself declared its ‘end of mission’ in April 2022.
8. Scatsat 1 – launched in September 2016, tracks and records wind data used to forecast weather, detect cyclones and in some other applications, listed as ‘in service’ but was decommissioned in February 2021 after a radio-frequency amplifier failed in an unfixable way.
9. EOS 1 – launched in November 2020, provides radar-imaging services in all weather conditions and in day and night, products used for applications related to land, water and environment management, part of the same ‘constellation’ of satellites as RISAT 2B and RISAT 2B-R1.
10. INSAT 3D and 3DR – former launched in July 2013, an advanced weather satellite, provides vertical temperature, humidity and ozone profiles in the atmosphere, includes a transponder for search and rescue operations; latter launched in September 2016 as a follow-up.

Communication satellites in service

1. GSAT 6, 8, 10, 11, 14, 15, 16, 17, 18, 19, 29, 30, 31
2. CMS 1 – launched in December 2020, provides C-band (4-8 GHz) services over the Indian mainland and the A&N and Lakshadweep islands.
3. South Asia Satellite – launched in May 2017, provides Ku-band (12-18 GHz) services over India, Afghanistan, Bangladesh, Bhutan, Maldives, Nepal and Sri Lanka.

5 major upcoming satellites

1. INS 2 and 2B – second generation nanosatellites (mass less than 10 kg), INS 2 will be a technology demonstrator and will carry a camera to measure the surface temperature of land and water bodies, INS 2B will carry a multispectral imager used to study forests, water bodies and snow-covered features.
2. GSAT 22-24 – three communications satellites with Ku band transponders for DTH services.
3. NISAR – a NASA-ISRO joint mission to study Earth’s biomass and frozen bodies (cryosphere), expected to be useful for climate studies.
4. HRSAT – a constellation of four satellites each with a panchromatic camera, a multispectral imager and a long-wave infrared camera, expected to be useful for urban planning, infrastructure development and disaster management.
5. EOS 4 and 6 – each with similar features as EOS 1 but with better capabilities in each iteration; GSLV F10 mission to launch EOS 3 satellite failed in August 2021 after leak in liquid hydrogen fuel tank.