The isro will send up an unusually large number of 10 earth observation (EO) satellites during 2020-21, according to the latest annual report of the Indian Space Research Organisation.

On a quick look, such a preponderance of the EO launches is unprecedented and includes new categories such as the first Geo Imaging Satellite, GISAT-1.

In comparison, only three communication satellites — which is another major category in space infrastructure — and two navigation satellites are planned for the coming financial year starting April.

The annual plan mentions 36 missions, another high for a year: these include both satellites and their launchers.

The high number also stands out amidst the immediate two years before and after the plan. For the ongoing fiscal, ISRO had proposed launching six EO satellites, of which two are due to go. For 2021-22, the plan is to add eight EO satellites.

ISRO says 19 national EO satellites, 18 communication satellites and eight navigation satellites are in service, driving uses from broadcasting, telephony, Internet services, weather and agriculture-related forecasting, security, disaster-time rescue and relief and location-based services. Three of the communication satellites are dedicated for military communication and networking.

The other EO satellites include highly advanced radar imaging satellites RISAT-2BR2, RISAT- 1A and 2A (with high agility X-band synthetic aperture radar), Oceansat-3 and Resourcesat-3/3A & SA. Risat satellites with high-spatial resolution will provide all-weather, day and night imaging services from space. They will be good for space surveillance and will mainly be used by security forces.

In the ongoing fiscal 2019-20, 17 missions have been planned to be launched and up to six of them are due to be completed by March 31.

A budget of Rs 13,480 crore has been proposed for the next fiscal in the recent budget for the Department of Space. Of it, Rs 265 has been allocated under the Space Sciences category and Rs 750 crore under the Insat Satellite System category. Most of the EO satellites to be launched in 2020-21 will be funded from the money allocated under these two categories.

The EO sats are ostensibly for benign uses such as land and agriculture watch. But their images also have a very important use for the military, for keeping an eye on the borders. The satellites such as RISATs, which carry a synthetic aperture radar on them, provide all-weather, 24-hour information to security agencies.

Apart from GISAT-1 that is apparently fixed over the subcontinent at an orbit 36,000 km high, the space agency plans to launch a new series of high-resolution HRSATs as a threesome on a single PSLV launcher.

The upcoming EO satellites include radar imaging satellites RISAT-2BR2, RISAT- 1A and 2A; Oceansat-3 and Resourcesat-3/3S.

The RISAT-2BR2 will form a triad fleet with its predecessors RISAT-2B and RISAT-2B1, all going around 120 degrees apart. They will “increase the frequency of observation in the areas of interest to provide all-weather, day/night imaging services from space,” the report said.