MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

Astronomy & Astrophysics 90 matter in the Universe. Using the redshifted hyperfine transition of neutral hydrogen as a tracer of these poorly understood cosmological epochs is one of the key science goals of the SKA (Probing the Cosmic Dawn). Ameasurement of the radio sky spectrum over 40 - 200MHz with radiometers and interferometers in the lunar farside is expected to provide a clean data set that can bolster confidence in foreground subtraction and systematics control of ground-based counterparts. Furthermore, dedicated experiments for detecting the signals from CD and EoR in the lunar farside are certain to yield groundbreaking results, solving the mysteries of what the first sources of radiation in the Universe were, when they formed, and how they ionised the Universe. With renewed interest in lunar exploration, these efforts of measuring the metre wavelength radio sky from the Moon are being looked upon favorably by space agencies all over the world. One experiment of note is the Netherlands- China Low Frequency Explorer (NCLE), that made measurements of the radio sky, in orbit around the Moon, in late 2019. NCLE operated over the 80 kHz - 80 MHz range. Several more experiments are expected to follow from countries around the world, in the form of lunar orbiters as well as interferometers deployed on the far side lunar surface. Of particular interest are the LuSEE, ROLSES and FARSIDE experiments from the United States, which are selected radio astronomy experiments that will operate on theMoon or in lunar orbit. In India, PRATUSH – Probing ReionizATion of the Universe using Signal fromHydrogen – is an experiment that has been proposed by researchers at the RRI. PRATUSH will be a custom designed, precision spectral-radiometer operating over 10-250 MHz, in orbit around the Moon. With a dedicated science goal of detecting the global (sky- averaged) signal from CD and EOR, it will make scientific measurements from the lunar far side and transmit data back to Earth when in the near side, thereby overcoming the limitations faced by ground based experiments on the Earth. With decades of experience in building ground-based precision radiometers, the group at RRI is now looking towards taking this expertise to the lunar farside. PRATUSH is currently in pre-project studies mode under an announcement of opportunity for astronomy payloads by ISRO (announced in 2018). The space-based radio astronomy era is blossoming. With concerted effort to explore these unchartered territories for scientific measurements, India can be at the forefront of the international radio-astronomy space-race in the modern era. 5.6.7 Space-Based SolarMissions The inter-disciplinary domains of solar astronomy, space weather and space sciences, collectively referred to as heliophysics, address the intersection of fundamental solar physics and translational research to characterize space weather and its impact on planets and our space-based technologies. Following the launch of India's first solar space mission Aditya-L1, the Indian heliophysics community has deliberated and converged upon a vision for solar and space weather observations from space that will complement and add to our (proposed) ground-based capabilities. Successful implementation of this vision over the course of next 15 years will place India at the forefront of space science and will enable India to generate indigenous data for observation, assessment and forecasting of the space environment. MEGA SCIENCE VISION-2035