NewSpace India Limited: the commercial arm of ISRO, a wholly owned company under the Department of Space

NewSpace India Limited (NSIL), incorporated on 6 March 2019 (under the Companies Act, 2013) is a wholly owned Government of India company, under the administrative control of Department of Space (DOS). It is the commercial arm of Indian Space Research Organisation (ISRO).
Its primary stated responsibility is enabling Indian industries to take up high technology space related activities, and it is also responsible for the promotion and commercial exploitation of the products and services emanating from the Indian space programme.
The company's major business areas are the production of Polar Satellite Launch Vehicle (PSLV) and Small Satellite Launch Vehicle (SSLV) through industry; the production and marketing of space-based services, including launch services and applications such as transponder leasing, remote sensing and mission support; the building of satellites, both communication and earth observation, as per user requirements; the transfer of technology developed by ISRO centres and units; the marketing of spin-off technologies; and consultancy services.
ISRO's own listing of its centres and units groups two central public sector enterprises under the Department of Space, Antrix Corporation Limited and NewSpace India Limited (NSIL), separately from IN-SPACe and from the autonomous bodies such as the Indian Institute of Space Science and Technology and the Physical Research Laboratory.
The company's registered address is at the ISRO HQ Campus, New BEL Road, Bengaluru.

Incorporated on: 6 March 2019 Incorporated under: Companies Act, 2013 Administrative control: Department of Space (DOS) Launch vehicles produced through industry: PSLV and SSLV
Why it matters for exams: Candidates routinely mix up the three space bodies set up outside ISRO's own centres. NSIL is a government company that sells and builds, Antrix is the older marketing company, and IN-SPACe is the authorising and supervising body, so knowing which is a company and which is not decides the answer.
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In plain words

NSIL NewSpace India Limited — A wholly government-owned company under the Department of Space that commercialises ISRO's products and services.

Transponder leasing Renting out capacity on a satellite's communication relay — A broadcaster or telecom operator pays to use part of a satellite already in orbit.