ISRO’s Call for Scientific Proposals

Last Updated: April 3, 2026
Science & Technology- Prelims

Science & Technology- Prelims

Context

The Indian Space Research Organisation (ISRO) has issued its second Announcement of Opportunity (AO), inviting proposals from the Indian solar physics community for observation time on the Aditya-L1 mission. This initiative aims to enhance scientific utilization of the data collected by India’s first dedicated solar observatory.

Core Mission

Primary Objective: Aditya-L1 is India’s first dedicated space-based solar mission.
Operational Location: The spacecraft is positioned at the Sun-Earth L1 (Lagrange Point 1- 1.5 million km from Earth).
Observation Capabilities: It conducts continuous, uninterrupted observations of the Sun from its stable orbit at the L1 point.
Data Policy: Scientific data gathered from the mission is regularly released into the public domain for global scientific use.

Launch Details:

Launch Vehicle: PSLV-C57
Launch Date: 2 September 2023
Launch Site: Satish Dhawan Space Centre

Technical Significance of L1 (Lagrange Point 1)

Uninterrupted View: A major advantage of placing a satellite in a halo orbit around the L1 point is that it provides a continuous view of the Sun without any occultation or eclipses.
Real-time Monitoring: This position allows for real-time tracking of solar activities and their impact on space weather.

Payloads (Instruments)

VELC – Visible Emission Line Coronagraph (main payload)
SUIT – Solar Ultraviolet Imaging Telescope
ASPEX – Solar wind particle experiment
PAPA – Plasma Analyser
MAG – Magnetometer

Key Achievements

Successfully inserted into halo orbit around L1 (Jan 2024)
Continuous solar observation started

Key Solar Missions (Globally)

PUNCH (NASA): It uses four suitcase-sized satellites to image the sun’s inner corona, bridging the gap between the sun and Earth to understand the origins of solar flares.
Proba-3 (ESA): The European Space Agency’s Proba-3 is designed to study the solar corona and solar winds by creating a solar eclipse using two high-precision satellites.
Solar Polar Orbit Observatory (China/NSSC): Planned for 2029, this mission aims to provide high-inclination views of the sun, which is crucial for understanding its magnetic field structure.
Parker Solar Probe (NASA): Currently orbiting in the sun’s atmosphere to analyze its structure, launched in 2018.
Solar Orbiter (ESA/NASA): Active since 2020, capturing high-resolution images of the Sun’s polar regions.

Solar Missions Match

Match the following solar missions:

Mission	Agency
1. PUNCH	NASA
2. Proba-3	ESA
3. Solar Polar Orbit Observatory	China
4. Parker Solar Probe	ESA

Select the correct answer:

(a) 1, 2 and 3 only

(b) 1 and 4 only

(d) 1, 2, 3 and 4

Answer: A

Explanation:

No.	Mission	Agency	Status	Key Details
1	PUNCH	NASA	Correct	Stands for Polarimeter to Unify the Corona and Heliosphere. It is a NASA mission designed to image the outer corona of the Sun.
2	Proba-3	ESA	Correct	A European Space Agency (ESA) mission. It is the world’s first precision formation-flying mission, creating an artificial eclipse to study the Sun’s faint corona.
3	Solar Polar Orbit Observatory	China	Correct	A proposed mission by China aimed at orbiting the Sun’s poles to study solar magnetic fields and the solar cycle.
4	Parker Solar Probe	ESA	Incorrect	The Parker Solar Probe is a flagship NASA mission (not ESA). It is the first spacecraft to “touch” the Sun by flying through the solar corona.