|Ambily Suresh, K. Nirmal and Ajin Prakash
Indian Institute of Astrophysics, India
Near space is the region of Earth's atmosphere that lies between 20 to 100 km above sea level, encompassing the stratosphere, mesosphere, and the lower thermosphere. Due to the major reduction in costs of all the involved components, from inexpensive latex balloons to easily available lightweight, compact and simple in operation micro-electromechanical (MEM) devices, small science instruments (such as telescopes/cameras) now can be flown onboard balloons or sounding rockets, to do serious science at low cost. These platforms are much cheaper than large-scale space missions and yet can yield substantial scientific output. We have initiated the High-Altitude Ballooning (HAB) programme at Indian Institute of Astrophysics (IIA) with the primary purpose of developing and flying low-cost scientific payloads on balloon-borne platforms; however, our instruments are versatile enough to operate on a range of near-space platforms, including cubesats, minisatellites, or even in space missions. A key requirement for HAB observations is the accurate and stable pointing platform, where the data can be stored for later retrieval or transmission. We have designed and manufactured a 2-axis light-weight, completely automated pointing and stabilization system to correct for payload random motions, where the crucial step is determination of the pointing direction, where the in-house developed attitude sensor provides the initial coarse pointing. For additional accuracy, we have developed a low-cost star tracker/sensor (StarSense) which comprises a Tessar lens focusing the light onto a radiation-hardened Star1000 C-MOS detector with a MIL-grade Spartan-6 FPGA readout. Development of the image-intensified UV detector on telescopic system for spectroscopic and imaging applications, using off-the-shelf MCPs, CMOS sensors and optics, to fly onboard the balloon or in space is also underway. Our other instruments include a compact all-spherical optical design ultraviolet (UV) space telescope to study bright objects in the near-UV domain that can be flown on a range of possible platforms such as high-altitude balloons, sounding rockets, LEO satellites, or space missions. A compact tunable spatial heterodyne spectrometer (TSHS) for remote sensing of extended targets including comets, interstellar medium, planetary atmospheres and heliosphere from space is also in development.