| Manufacturer | ISRO |
|---|---|
| Country of origin | India |
| Operator | ISRO |
| Applications | Data transmission |
| Specifications | |
| Bus | I-2K[1] |
| Launch mass | Less than 3,000 kilograms (6,600 lb) |
| Regime | Geostationary |
| Production | |
| Status | Planned |
| Maiden launch | IDRSS-1 2025-26[2] (planned) |
Indian Data Relay Satellite System orIDRSS is a planned Indianconstellation ofInter-satellite communications satellites. It is planned to initially comprise two satellites, CMS-04 (formerly IDRSS-1) & IDRSS-2 ingeostationary orbit. It will facilitate relay of information between various Indian spacecraft, in-flight launch vehicle monitoring and assist theIndian Human Spaceflight Programme.[3][4]
A Data Relay Satellite System (DRSS) facilitates continuous real-time communication betweenLow Earth orbit bound spacecraft to theground station as well as inter-satellite communication. Such a satellite in geostationary orbit can track a low altitude spacecraft up to almost half of its orbit.
India operates one of world's largestremote sensing satellites systems. Visibility of these satellites is not more than 10–15 minutes in a day and sometimes even lower. The IDRSS satellites, one opposite to each half of earth inGEO, can see about 80 per cent of the area where Indian remote sensing satellites are orbiting, hence enhancing visibility range and data transfer rates of satellites. IDRSS can also monitor a launch vehicle from the time it lifts off from the launch pad. Satellites will hereby also reduce dependency on ground stations. Implementation of the system will be essential for trackingGaganyaan,India's future crewed spacecraft.
The main objectives of IDRSS are:
IDRSS satellites would be based on 2,000 kg class, I-2K extended bus and will be compatible for launch onboard GSLV Mk-II Launch Vehicle.[5]
The deployable antenna system will interface with the satellite by means of a deployable, pointing and tracking mechanism along with a S band rotary joint.[5] Satellites might carryoptical communication payload for increased data security and high transfer rates.[6][predatory publication]
| Satellite | Int. Sat. ID | NORAD ID | Launch Date | Launch Vehicle | Orbit | Status | Remarks |
|---|---|---|---|---|---|---|---|
| CMS-04 (IDRSS-1) | TBD | TBD | 2025-26[7] | GSLV[8] | GSO | Planned | |
| IDRSS-2 | TBD | TBD | 2025-26[7] | GSLV[8] | GSO | Planned |
IDRSS was approved by theGovernment of India and had funds allocated inbudget of 2019-20.[9] CMS-04 would be the first spacecraft in the IDRSS constellation,[3][10] and its launch is currently scheduled for 2025-26.[7]