PRATUSH Radiometer to Probe the Dawn of the Cosmos

The PRATUSH radiometer is a new generation space payload intended to research the Cosmic Dawn, when the earliest stars and galaxies were born. Constructed around a small single-board computer (SBC), which is only a credit-card size, the system will work in lunar orbit to watch faint 21-cm hydrogen line signals lost in Earth-based interference.

Exploring the Cosmic Dawn

The Cosmic Dawn was the turning point of the Universe when the first stars caused hydrogen reionisation and caused the formation of cosmic structures. This makes direct evidence of this epoch very rare as the signals are very weak and can easily be buried by the radio noise of the earth.

Role and Design

PRATUSH will be run on the radio quiet far side of the moon where ionospheric distortion is nonexistent. It has an antenna, analog receiver, and a digital receiver built into its radiometer and controlled by an SBC. The two of them work together to capture and process subtle radio emission of neutral hydrogen within the initial Universe.

Master Controller

At its center is a single-board computer, at present comparable to a Raspberry Pi, that controls the antenna and FPGA chip. It logs, and calibrates and stores high-speed data streams. The next generation of space-qualified SBCs will be based on the commercial prototypes tested in a lab.

Technical Advances

• Low noise sensitivity: has been shown to be down to a few millikelvins.
• Lightweight, energy efficient design: Suited to space missions where power and mass are severely restricted.
• Scalable architecture: Software-hardware upgrades will provide even more accuracy in future missions.

Significance

PRATUSH represents a rapidly increasing trend towards miniaturised, cost effective instruments in space science. It would unlock the signals of the earliest epoch in the history of the Universe, and thus illuminate the formation of the first stars, galaxies, and potentially new physics. It is located on the far side of the Moon, and it shows that even small, high-performance systems can make big cosmological finds.