India's Department of Space, through the Indian Space Research Organisation (ISRO), is advancing plans for its inaugural quantum communication satellite as part of the National Quantum Mission (NQM). 

his initiative aligns with the mission's goal to establish satellite-based secure quantum communications over distances up to 2000 kilometres within the country. The project builds on ground-based demonstrations and aims to deliver un-hackable data links critical for national security.

The NQM, approved in April 2023 with a budget of ₹6,003.65 crore spanning 2023-24 to 2030-31, prioritises quantum technologies including communication. Satellite-based quantum key distribution (QKD) forms a core deliverable, enabling long-distance secure links resistant to quantum computing threats. ISRO collaborates with institutions like the Raman Research Institute (RRI) on this front, with funding exceeding ₹15 crore since 2017.

A dedicated satellite named SAQTI—Secured Applications using Quantum and optical Technologies by ISRO—represents the flagship effort. Anticipated for launch around 2025-2026, SAQTI will demonstrate space-based QKD, extending trials from ground distances of 300 metres to orbital operations. This timeline fits the user's 4-5 year horizon from late 2025, potentially slipping to 2027-2030 amid development complexities.

Quantum communication leverages principles like entanglement and superposition for QKD, generating encryption keys that detect eavesdropping instantly. Unlike classical methods vulnerable to quantum attacks, such as those from future computers breaking RSA algorithms, QKD ensures information-theoretic security. India's free-space trials, including over 1 km by DRDO and IIT Delhi in 2025, validate atmospheric feasibility at rates of 240 bits/s.

ISRO's roadmap includes SAQTI alongside missions like TDS-01 for quantum payload tests, targeting 2000 km links. Complementary efforts involve post-quantum cryptography (PQC) satellites via private partnerships, such as Space TS and Synergy Quantum, focusing on encrypted systems and ground infrastructure. These aim for sovereign resilience against quantum cyber threats by early 2030.

Groundwork includes a 100 km fibre QKD link in 2022 and 500 km networks in 2025 by QNu Labs and the Indian Army. Multi-core fibre trials by C-DOT and STL integrate quantum keys with classical data over 100 km. Such advancements pave the way for hybrid networks blending terrestrial and satellite QKD.

The Department of Space oversees ISRO's role within NQM's Thematic Hubs, particularly IIT Madras for quantum communication. Private sector involvement, including startups like QNu Labs, accelerates commercialisation with products like QRNG Tropos. International benchmarks, such as China's Micius satellite since 2016, underscore urgency, yet India's indigenous push emphasises self-reliance.

Challenges persist in scaling from labs to orbit, including atmospheric turbulence mitigation and qubit stability. Policy priorities call for public-private partnerships, PQC standardisation, and talent development via B.Tech/M.Tech curricula. By 2030-2031, operational quantum satellite networks could secure defence, finance, and governance amid global quantum races.

Strategic implications extend to geopolitical edges, safeguarding military C4ISR against decryption risks. NQM's hubs at IISc, IITs Madras, Bombay, and Delhi foster 152 researchers across 43 institutions. Supported startups, now eight strong, target global competitiveness, aligning with NITI Aayog's 2035 vision for quantum self-reliance.

Launch vehicles like PSLV, potentially industry-built by 2026, will deploy these payloads from Satish Dhawan Space Centre. Integration with Gaganyaan and Oceansat schedules signals a busy 2026, blending human spaceflight with quantum demos. Success hinges on indigenisation, from photon sources to atomic clocks for precision navigation.

India's quantum satellite odyssey positions the nation among leaders like the US and Europe by decade's end. Free-space optics from sites like Hanle Observatory in Ladakh offer optimal conditions. This endeavour not only fortifies digital sovereignty but catalyses economic growth through quantum tech ecosystems.

Agencies

​