PROBA - 3

1. Context

The Indian Space Research Organisation (ISRO) will launch the European Space Agency’s Proba-3 mission on its PSLV rocket to study the solar corona, the outermost and hottest part of the Sun’s atmosphere, from Sriharikota on December 4.

2. What is Proba-3?

Proba-3, developed at an estimated cost of 200 million euros, is anticipated to have a mission duration of two years. It will be launched into a highly elliptical orbit with dimensions of approximately 600 x 60,530 km and an orbital period of 19.7 hours.

The mission comprises two satellites that will be launched together. After separation, they will operate in tandem to function as a solar coronagraph. This instrument blocks the Sun's intense light, enabling observation of its surrounding atmosphere and celestial objects

3. What does Proba-3 Study?

Observing the Sun's corona, which can reach temperatures of up to 2 million degrees Fahrenheit, presents significant challenges for instruments. Nonetheless, studying the corona is crucial, as it is the origin of space weather phenomena like solar storms and solar winds. These events can disrupt satellite-based communication, navigation systems, and power grids on Earth.

To investigate these effects, Proba-3 is equipped with three advanced instruments:

Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun (ASPIICS): This coronagraph focuses on the Sun's outer and inner corona, typically visible during solar eclipses. It features a 1.4-meter occulting disk to block sunlight, enabling detailed observations of this region.
Digital Absolute Radiometer (DARA): This instrument continuously measures the Sun’s total energy output, known as total solar irradiance.
3D Energetic Electron Spectrometer (3DEES): Designed to measure electron fluxes in Earth's radiation belts, this instrument provides valuable data for understanding space weather

4. How is Proba-3 different from others?

The two satellites, the Occulter Spacecraft (200 kg) and the Coronagraph Spacecraft (340 kg), are designed to simulate a solar eclipse by precisely aligning in Earth's orbit. This alignment enables one satellite to cast a shadow onto the other, mimicking the natural conditions of an eclipse.
While a natural solar eclipse allows solar physicists to observe the Sun’s corona for approximately 10 minutes during an average of 1.5 eclipse events per year, Proba-3 will provide six hours of observation time, equivalent to 50 eclipse events annually. This extended observation period will significantly enhance the study of the Sun's corona.
Both satellites will continuously face the Sun and maintain a precise formation within a few millimetres. They will then separate to a distance of 150 metres for six-hour observation periods. In this arrangement, one satellite will serve as a telescope, positioned at the centre of the shadow cast by the other satellite, which blocks direct sunlight.
Through this stable and artificial eclipse created by the Occulter, the Sun’s intense light will be obscured, allowing the coronagraph to capture detailed images and facilitate in-depth studies of the solar corona’s lesser-known aspects. This entire process will rely on autonomous and precise flight formation

5. Benefits of Proba-3 to India

Proba-3 is recognized as a technology demonstration mission by the European Space Agency (ESA). The selection of ISRO to launch this mission highlights India’s dependable space launch infrastructure and advancing capabilities in the space sector. The mission's cost-effective launch further adds to its appeal.

Additionally, there is a significant likelihood that Indian solar physicists will gain exclusive access to data from Proba-3. Notably, some Indian researchers have collaborated with their Belgian counterparts in shaping the mission's scientific objectives

Source: Indianexpress

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PROBA - 3

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