In News:

Scientists at the Raman Research Institute (RRI), Bengaluru, with support from the Department of Science and Technology (DST) and collaboration with ISRO, have proposed a pioneering lunar mission called PRATUSH (Probing ReionizATion of the Universe using Signal from Hydrogen). This futuristic radiometer aims to detect faint 21-cm radio signals from hydrogen atoms, which hold imprints of the Cosmic Dawn—the epoch when the first stars and galaxies formed, fundamentally shaping the Universe.

The Science of the Cosmic Dawn

• The Cosmic Dawn marks the birth of the first stars and galaxies, initiating the reionization of the Universe.
• Detecting the 21-cm hydrogen signal is crucial to study this epoch, but the signal is extremely faint, buried under strong terrestrial radio interference.
• The far side of the Moon—a naturally radio-quiet zone—offers the ideal site for such observations, free from Earth’s radio noise and ionospheric distortions.

About PRATUSH Payload

• Type: Radiometer telescope for low-frequency radio astronomy.
• Orbit: Preferred circumlunar orbit around the far side of the Moon.
• Core Components:
  • Wideband frequency-independent antenna (30–250 MHz).
  • Self-calibratable analog receiver.
  • Digital correlator with 100 kHz spectral resolution.
• Mission Strategy:
  • Continuous observation of large sky regions.
  • Recording beam-averaged radio spectra at high spectral resolution.
  • Nominal lifetime: Two years, ensuring high signal-to-noise ratio with broad sky coverage.

Role of Single-Board Computer (SBC)

At the heart of PRATUSH lies a compact Single-Board Computer (SBC), initially modeled on a Raspberry Pi, designed to overcome stringent size, weight, and power (SWaP) constraints of space missions.

Functions of SBC:

• Master controller of the radiometer system.
• Coordinates antenna, analog receiver, and Field Programmable Gate Array (FPGA) for digital processing.
• Records, stores, and calibrates high-speed data streams.
• Performs preliminary data processing onboard.

Performance:

• Laboratory tests collected 352 hours of reference data, reducing receiver noise to just a few millikelvins, confirming its sensitivity to the Cosmic Dawn signal.
• Next-generation space-grade SBCs will replace commercial models for flight.

Significance of PRATUSH

• Scientific Breakthrough:
  • May unlock how the first stars sculpted the Universe.
  • Potential to discover new physics related to early cosmic evolution.
• Technological Innovation:
  • Demonstrates the effectiveness of low-power, miniaturized controllers in deep-space astronomy.
  • Showcases India’s ability to design low-mass, high-capability payloads.
• Strategic Value:
  • Strengthens India’s presence in lunar science and radio astronomy.
  • Enhances collaboration between RRI, DST, and ISRO.
• Global Impact:
  • Contributes to humanity’s collective effort to detect the Universe’s earliest signals.
  • Positions India as a frontrunner in next-generation space astrophysics.