Question of the Day – Proba 3 mission
QOTD March 10,2026
With reference to the PSLV‑C59/PROBA‑3 Mission, consider the following statements:
- The mission involves launching two satellites of the European Space Agency to demonstrate precise formation flying in space.
- The satellites were launched into a highly elliptical Earth orbit using the Polar Satellite Launch Vehicle (PSLV).
- The mission aims to study the Sun’s corona by creating an artificial eclipse using two spacecraft.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation:
Statement 1-Correct
PROBA-3 is an In-Orbit Demonstration mission of ESA consisting of two spacecraft designed to demonstrate highly precise formation flying technology in space.
Statement 2-Correct
The mission was launched on 5 December 2024 using the PSLV-C59 rocket from the Satish Dhawan Space Centre, placing the satellites into a highly elliptical orbit around Earth.
Statement 3-Correct
The two spacecraft — Occulter Spacecraft and Coronagraph Spacecraft — fly about 150 meters apart to simulate a solar eclipse, allowing scientists to study the Sun’s corona for long durations.
Why in news–
The PSLV‑C59/PROBA‑3 Mission is in the news because the Indian Space Research Organisation successfully launched the PROBA‑3 Mission of the European Space Agency using the Polar Satellite Launch Vehicle (PSLV) from the Satish Dhawan Space Centre in December 2024. The mission carries two satellites that will fly in extremely precise formation in space to simulate a solar eclipse and enable long-duration observation of the Sun’s corona. This mission is significant because it demonstrates advanced formation-flying technology and highlights growing international collaboration in space missions, with India providing the launch services for a major European scientific experiment.
News-https://www.isro.gov.in/PSLV_C59_PROBA-3_Mission.html
There are more questions from this topic that you should practice to make your concepts stronger.
Practice Questions (PQ)
PQ1. With reference to the Polar Satellite Launch Vehicle (PSLV), consider the following statements:
- PSLV is a four-stage launch vehicle using both solid and liquid propellants.
- It is capable of launching satellites into multiple orbits in a single mission.
- PSLV is primarily designed only for Geostationary Transfer Orbit (GTO) missions.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (a)1 and 2 only
Explanation
Statement 1-Correct
PSLV is a four-stage launch vehicle with alternating solid and liquid propellant stages.
Statement 2-Correct
PSLV can launch multiple satellites and place them in different orbits during the same mission.
Statement 3-Incorrect
PSLV mainly launches satellites into Polar Sun-synchronous orbit and Low Earth Orbit, not primarily for GTO missions.
PQ2. With reference to the PROBA‑3 Mission, consider the following statements:
- The mission consists of two spacecraft called the Occulter Spacecraft and Coronagraph Spacecraft.
- The spacecraft operate in formation to block sunlight and observe the solar corona.
- The mission is operated entirely by the Indian Space Research Organisation.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (a)1 and 2 only
Explanation:
Statement 1-Correct
PROBA-3 consists of two spacecraft — Occulter Spacecraft (OSC) and Coronagraph Spacecraft (CSC).
Statement 2-Correct
They fly in formation so that one spacecraft blocks sunlight, enabling the other to observe the Sun’s corona.
Statement 3-Incorrect
The mission belongs to the European Space Agency, while ISRO provided the launch vehicle.
PQ3.Consider the following pairs:
| Mission | Space Agency |
|---|---|
| 1. PROBA-3 | European Space Agency |
| 2. Aditya-L1 | Indian Space Research Organisation |
| 3. Solar Orbiter | NASA |
How many of the above pairs are correctly matched?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (b) Only two
Explanation:
Pair 1-Correct
PROBA-3 is a mission of the European Space Agency.
Pair 2-Correct
Aditya‑L1 is India’s first dedicated solar mission by Indian Space Research Organisation.
Pair 3-Incorrect
Solar Orbiter is a joint mission of ESA and NASA, not NASA alone.
Previous Year Question (UPSC Prelims)
With reference to the Polar Satellite Launch Vehicle (PSLV), consider the following statements:
- PSLV is designed mainly to deliver satellites into Sun-synchronous orbit.
- PSLV can launch multiple satellites in a single launch.
- PSLV is capable of placing satellites into Geosynchronous orbit.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Statement 1-Correct
PSLV was originally developed to launch satellites into Sun-synchronous polar orbit, commonly used for Earth observation satellites.
Statement 2-Correct
PSLV has demonstrated the capability to launch many satellites in a single mission (e.g., record launch of 104 satellites in 2017).
Statement 3-Correct
Although primarily used for polar missions, PSLV can also place satellites into Geosynchronous Transfer Orbit (GTO) for certain missions.
