Indian Satellites and NavIC: Series, Firsts and MCQs
Exam notes on Indian satellites and NavIC: Aryabhata, APPLE, INSAT, GSAT, IRS, Kalpana-1, Astrosat, Aditya-L1 and the seven-satellite NavIC constellation.
By GK24 Editorial Team· Published · 4 min read
Satellites are the part of the space programme that pays for itself: they carry telephone calls and television, photograph crops and floods, warn of cyclones and now tell a fisherman where he is. Questions from this chapter are of two kinds, the firsts with their years and the NavIC system with its numbers. Both are collected below.
The first Indian satellites
Aryabhata, India's first satellite, was launched on 19 April 1975 by a Soviet launch vehicle and was built to study X-ray astronomy and the ionosphere. Bhaskara-1 followed in 1979 as the first experimental earth observation satellite. In 1980 Rohini RS-1 became the first satellite placed in orbit by an Indian vehicle, SLV-3. APPLE, the Ariane Passenger Payload Experiment, was launched in 1981 on a European Ariane rocket and was India's first experimental communication satellite; it is remembered in photographs for being moved on a bullock cart at the test site.
The families of satellites
| Series | Purpose | Point to remember |
|---|---|---|
| INSAT and GSAT | Communication and broadcasting | Geostationary orbit, controlled from Hassan |
| IRS, Resourcesat, Oceansat | Earth observation | IRS-1A in 1988 was the first operational remote sensing satellite |
| Cartosat | Mapping and cartography | High resolution imagery for urban and land use maps |
| RISAT | Radar imaging | Sees through cloud and works at night |
| INSAT-3D and Kalpana-1 | Meteorology | Kalpana-1, 2002, first exclusively meteorological satellite |
| IRNSS and NVS | Navigation | The NavIC constellation |
Three single satellites are asked by name. EDUSAT, launched in 2004, was the first Indian satellite meant only for education and classroom broadcasting. Kalpana-1 of 2002 was renamed in memory of the astronaut Kalpana Chawla and was the first satellite devoted only to meteorology. Astrosat, launched on 28 September 2015, was India's first dedicated multi-wavelength space observatory, able to study a source in the ultraviolet, the visible and the X-ray bands at the same time.
Science missions
Chandrayaan-1 reached the moon in 2008 and its impact probe helped confirm water molecules there. The Mars Orbiter Mission, launched in November 2013, entered Mars orbit in September 2014 and made India the first country to succeed at Mars on its first attempt. Chandrayaan-2 followed in 2019 and Chandrayaan-3 landed near the lunar south pole in August 2023. Aditya-L1, India's first solar observatory, was launched on 2 September 2023 and placed in a halo orbit around the first Lagrange point, about 1.5 million kilometres from the earth, from where it can watch the sun without eclipse. XPoSat, launched on 1 January 2024, studies the polarisation of X-rays from cosmic sources.
NavIC, India's own navigation system
The Indian Regional Navigation Satellite System was renamed NavIC, short for Navigation with Indian Constellation, in 2016. It was built because a country cannot depend on another nation's system for military and civil navigation.
- Constellation: designed as seven satellites, three in geostationary orbit and four in geosynchronous orbits inclined to the equator.
- Coverage: India and a region extending about 1,500 km beyond its boundary, which is why it is called a regional and not a global system.
- Services: the Standard Positioning Service, open to all users, and the Restricted Service, an encrypted service for authorised users.
- Accuracy: better than 20 metres over the Indian landmass, with timing accuracy better than 50 nanoseconds.
- Signals: transmitted in the L5 and S bands, unlike the L band alone used by most global systems.
The first satellite of the series, IRNSS-1A, went up on 1 July 2013, and IRNSS-1G in April 2016 completed the set of seven, the occasion on which the system received the name NavIC. Every IRNSS satellite was launched by the PSLV-XL. IRNSS-1H was lost in 2017 when the heat shield of the rocket failed to separate, and IRNSS-1I was launched in 2018 to fill the gap. The second-generation series began with NVS-01, launched by GSLV-F12 in May 2023, which carried an indigenous rubidium atomic clock and added a civil signal in the L1 band so that ordinary phones and chips can use NavIC more easily. NavIC is used for road and marine navigation, fleet and vehicle tracking, fishermen safety alerts, disaster warning and precise timing.
GAGAN and the other systems
GAGAN, the GPS Aided GEO Augmented Navigation system, is a joint project of ISRO and the Airports Authority of India. It does not replace satellite navigation but corrects it, giving aircraft the accuracy needed to approach and land. The world's other systems are worth learning as pairs: GPS of the United States, GLONASS of Russia, Galileo of the European Union, BeiDou of China and QZSS of Japan, of which QZSS and NavIC are regional while the rest are global.
Exam Point of View
Most marks here come from firsts and full forms. Learn the chain 1975 Aryabhata, 1979 Bhaskara-1, 1980 Rohini, 1981 APPLE, 1988 IRS-1A, and the single-purpose satellites Kalpana-1, EDUSAT and Astrosat with their years. On NavIC the four favourite facts are the full form, the seven satellites split three and four, the roughly 1,500 km coverage beyond the border and the two services. Distinguish NavIC from GAGAN, which only augments signals for aviation, and remember that NavIC is regional while GPS, GLONASS, Galileo and BeiDou are global. Common traps are giving Aryabhata an Indian launch vehicle, calling NavIC a global system, and attributing GAGAN to the Indian Air Force instead of the Airports Authority of India.
Important Facts
| India's first satellite | Aryabhata, 19 April 1975, on a Soviet launch vehicle |
|---|---|
| First satellite launched by an Indian vehicle | Rohini RS-1, 18 July 1980, by SLV-3 |
| First experimental communication satellite | APPLE, 1981, launched by Ariane |
| First operational remote sensing satellite | IRS-1A, 1988 |
| First exclusively meteorological satellite | Kalpana-1, 2002, named after Kalpana Chawla |
| First satellite for education | EDUSAT, 2004 |
| First multi-wavelength space observatory | Astrosat, 28 September 2015 |
| First solar observatory | Aditya-L1, launched 2 September 2023, at the first Lagrange point |
| NavIC full form | Navigation with Indian Constellation; earlier IRNSS |
| NavIC constellation | Seven satellites: three geostationary, four in inclined geosynchronous orbits |
| NavIC coverage | India and about 1,500 km beyond its boundary |
| NavIC services | Standard Positioning Service and encrypted Restricted Service |
| NavIC accuracy | Better than 20 metres over the Indian landmass |
| First NavIC satellite | IRNSS-1A, 1 July 2013, by PSLV-XL |
| GAGAN | GPS Aided GEO Augmented Navigation, by ISRO with the Airports Authority of India |
Practice MCQs on this topic
Which was India's first satellite and in which year was it launched?
- A.Rohini, 1980
- B.Aryabhata, 1975
- C.Bhaskara-1, 1979
- D.APPLE, 1981
Show answer
It was launched on 19 April 1975 by a Soviet launch vehicle, since India had no vehicle of its own at the time, and it carried experiments in X-ray astronomy, solar physics and the ionosphere.
Read the full explanation →What does NavIC stand for?
- A.Navigation with Indian Constellation
- B.National Voyage and Indian Communication
- C.Navigation Indian Coordinates
- D.Navigational Information Centre
Show answer
The name was given in 2016 to the Indian Regional Navigation Satellite System, IRNSS, when the seventh satellite of the constellation was placed in orbit, and the word navik also carries the sense of a sailor or navigator, which is why it was chosen.
Read the full explanation →The NavIC constellation was designed with how many satellites?
- A.Four
- B.Seven
- C.Nine
- D.Twenty-four
Show answer
The system was designed as a constellation of seven satellites, three of them in geostationary orbit and four in geosynchronous orbits inclined to the equatorial plane, a small number being enough because the service area is regional and not global.
Read the full explanation →Which was India's first satellite dedicated exclusively to meteorology?
- A.INSAT-1B
- B.Kalpana-1
- C.Bhaskara-2
- D.Oceansat-1
Show answer
Launched in 2002 as METSAT, it was the first Indian satellite built only for weather work, and it was renamed Kalpana-1 in memory of Kalpana Chawla, the India-born astronaut who died in the Columbia accident of 2003.
Read the full explanation →Astrosat, launched in September 2015, was India's first satellite of which kind?
- A.Radar imaging satellite
- B.Dedicated multi-wavelength space observatory
- C.Navigation satellite
- D.Educational satellite
Show answer
Astrosat was launched on 28 September 2015 by a PSLV and carries instruments that observe the same cosmic source in the ultraviolet, the visible and the X-ray bands at the same time, which is what multi-wavelength means and what makes the mission unusual among space telescopes of its size.
Read the full explanation →India's solar mission Aditya-L1 has been placed in a halo orbit around which point?
- A.The second Lagrange point, L2
- B.The first Lagrange point, L1
- C.A polar orbit around the sun
- D.A geostationary orbit around the earth
Show answer
A Lagrange point is a place where the gravitational pulls of the two bodies and the orbital motion balance, so a spacecraft can stay there with very little fuel, and from L1 the sun can be watched continuously without eclipse or occultation.
Read the full explanation →Which was India's first operational remote sensing satellite?
- A.Bhaskara-1
- B.IRS-1A
- C.Cartosat-1
- D.RISAT-1
Show answer
The correct answer is B, IRS-1A, launched in 1988, which began the Indian Remote Sensing series and was the first such satellite whose data was used routinely for crop assessment, forest mapping, water resources and land use rather than only for experiment.
Read the full explanation →The satellite navigation system BeiDou belongs to which country?
- A.Japan
- B.Russia
- C.China
- D.European Union
Show answer
BeiDou is the Chinese global navigation satellite system, built in phases and now offering worldwide coverage, and the name is the Chinese term for the constellation of the Big Dipper.
Read the full explanation →GAGAN, the satellite based augmentation system, is a joint project of ISRO and which organisation?
- A.Indian Air Force
- B.Airports Authority of India
- C.Indian Meteorological Department
- D.Directorate General of Shipping
Show answer
GAGAN stands for GPS Aided GEO Augmented Navigation and was developed by ISRO together with the Airports Authority so that civil aircraft in Indian airspace get position information accurate and reliable enough for approach and landing.
Read the full explanation →APPLE, India's first experimental communication satellite, was launched in 1981 by which launch vehicle?
- A.SLV-3 of India
- B.A Soviet launch vehicle
- C.The European Ariane rocket
- D.A United States Space Shuttle
Show answer
The full name of the satellite, Ariane Passenger Payload Experiment, contains the answer, since it flew as a passenger on an Ariane launch in 1981 to test the building of a geostationary communication satellite in India.
Read the full explanation →Frequently Asked Questions
What is the full form of NavIC?
Navigation with Indian Constellation. It is the name given in 2016 to the Indian Regional Navigation Satellite System, IRNSS, when the seventh satellite of the constellation was placed in orbit.
How many satellites does the NavIC constellation have and in which orbits?
It is designed as a constellation of seven satellites, three of them in geostationary orbit and four in geosynchronous orbits inclined to the equatorial plane. The inclined satellites trace a figure over the Indian region and improve coverage at higher latitudes.
Why is NavIC called a regional system?
Because it is designed to serve India and an area extending about 1,500 km beyond its boundary rather than the whole earth. GPS, GLONASS, Galileo and BeiDou are global systems; NavIC and Japan's QZSS are regional.
Which was India's first satellite and who launched it?
Aryabhata, launched on 19 April 1975 by a Soviet launch vehicle from Kapustin Yar, since India then had no launch vehicle of its own. It was named after the ancient Indian mathematician and astronomer and carried experiments in X-ray astronomy.
What is the difference between NavIC and GAGAN?
NavIC is a navigation system with satellites of its own that give position and time. GAGAN is an augmentation system: it does not provide the basic signal but corrects the signals of existing satellites so that aircraft get the accuracy and reliability that landing requires. GAGAN is run by ISRO with the Airports Authority of India.
Where is Aditya-L1 placed and why?
In a halo orbit around the first Lagrange point of the sun and the earth, roughly 1.5 million kilometres from the earth in the direction of the sun. From there the spacecraft can observe the sun continuously without being blocked by eclipses or by the earth.
Sources
- Indian Space Research Organisation: satellites and navigation programmes — ISRO
- Annual Report of the Department of Space — Department of Space, Government of India
