In News:

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.

Key Highlights:

• Mission Objective:The mission will study the Sun’s outermost and hottest atmosphere, the solar corona. The mission will also demonstrate the first-ever precision formation flying with two satellites working in tandem.
• Satellite Formation:Proba-3 consists of two satellites that will fly together, maintaining a fixed formation to study the Sun's corona.

What is Proba-3?

• Proba-3 is a solar mission developed by ESA, with an estimated cost of 200 million euros. The mission involves launching two satellites that will separate after launch, but fly in precise formation. The satellites will create a solar coronagraph, which blocks the Sun’s bright light to observe the solar corona, the Sun’s outermost atmosphere.
• Orbit: Proba-3 will orbit in a highly elliptical path (600 x 60,530 km) with an orbital period of 19.7 hours.
• Mission Duration: The expected mission life is two years.

What will Proba-3 Study?

The Sun's corona is extremely hot (up to 2 million degrees Fahrenheit), making it difficult to observe with conventional instruments. However, studying the corona is essential because it generates space weather phenomena such as solar storms and solar winds, which can impact satellite communications, navigation systems, and power grids on Earth.

Proba-3 will use three main instruments for its mission:

• ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun):This coronagraph will observe the Sun’s outer and inner corona, similar to how the corona is visible during a solar eclipse. It features a 1.4-meter occulting disk to block the Sun’s light and facilitate close-up observations.
• DARA (Digital Absolute Radiometer):This instrument will measure the Sun’s total energy output (total solar irradiance).
• 3DEES (3D Energetic Electron Spectrometer):It will study electron fluxes as they pass through Earth's radiation belts, providing valuable data on space weather.

Why is Proba-3 Unique?

• Proba-3 is designed to mimic a natural solar eclipse, allowing continuous study of the Sun’s corona. Typically, solar scientists observe the corona for only about 10 minutes during an eclipse, occurring around 1.5 times a year. Proba-3 will provide up to six hours of data per day, equivalent to 50 eclipse events annually.
• The two satellites will maintain a precise formation, with one acting as an occulting spacecraft to cast a shadow, while the other (the coronagraph) stays in the shadow and observes the Sun’s corona. They will be positioned 150 meters apart, maintaining their formation autonomously.
• This artificial eclipse will enable scientists to study the corona and its less-understood features more effectively.

In News:

Europe's Proba-3 mission to arrive in India for launch aboard PSLV-XL by ISRO

Key Highlights:

• Objective: The Proba-3 mission, led by the European Space Agency (ESA), aims to observe the Sun’s corona by creating an artificial solar eclipse. This will allow continuous observation of the Sun’s faint outer atmosphere, which is typically only visible during a natural solar eclipse.
• Key Features:
  • Artificial Solar Eclipse: The two spacecraft will fly in formation to maintain a shadow between them, enabling the uninterrupted observation of the solar corona.
  • Formation Flying: The satellites must maintain a precise formation with an accuracy of one millimetre, equivalent to the thickness of a fingernail.

Mission Details

• Launch Date: Scheduled for December 4, 2024.
• Launch Location: Satish Dhawan Space Centre near Chennai, India.
• Launch Vehicle: The PSLV-XL rocket developed by ISRO will be used for the launch.
• Spacecraft Mass: The combined mass of the two spacecraft is 550 kg.
• Orbit: The spacecraft will be placed in a highly elliptical orbit with a maximum altitude of 60,000 km to facilitate the precise formation flying.
  • This high altitude minimizes Earth’s gravitational pull and reduces the amount of propellant required to maintain their positions during the mission.

Mission Significance

• Solar Observation: The primary objective is to observe the Sun’s corona, which has been challenging to study due to its faintness. The artificial eclipse will allow continuous data collection on solar activity.
• Formation Flying: This technology will allow the two satellites to maintain autonomous flight with millimetre-level precision, which is a significant advancement in satellite formation control.
• Six-Hour Observation Windows: Each formation flying session will last for up to six hours, during which the satellites will observe the Sun's corona.

Technological and Scientific Contributions

• ASPIICS Instrument: The ASPIICS (AStronomical PIcture Camera for the Intense Corona of the Sun) will be the mission's primary instrument, developed by the Royal Observatory of Belgium. It will provide crucial data on solar activity and space weather.
• International Collaboration: The mission is a collaborative effort involving 14 ESA member states and various organizations across Europe.
• Mission Control: The mission will be managed from the ESA’s European Space Operations Centre (ESOC) in Belgium, with significant pre-launch training and preparations already underway.

ISRO's Role and Historical Context

• Launch by ISRO: The Proba-3 mission will be ISRO’s first launch for ESA since 2001, marking an important milestone in India-Europe space cooperation.
• PSLV-XL Rocket: ISRO’s PSLV-XL rocket is known for its reliability and capability in deploying satellites into precise orbits. It is well-suited to carry the 550 kg Proba-3 duo into a highly elliptical orbit for the mission.