NEW DELHI — India is set to launch a rocket carrying the indigenously built Radar Imaging Satellite (Risat-1) on April 26, according to a senior official of the Indian Space Research Organization (ISRO).

“India’s very own Polar Satellite Launch Vehicle [PSLV-C19] will inject the 1,858-kilogram Risat-1 satellite into an orbit of 480 kilometers [300 mi.] altitude at an inclination of 97.552 degrees,” the official says.

“The satellite will be put in its final orbital configuration at 536-km altitude using thrusters onboard the satellite.”

The Launch Authorization Board at the Satish Dhawan Space Center, Sriharikota, has cleared the launch of the PSLV-C19/Risat-1 mission at 5:47 a.m. IST on April 26, the official says. The 71-hr. countdown began at 6:47 a.m. local time on April 23.

During the countdown, the liquid-propellant second stage and fourth stage of the launch vehicle will be fueled. Besides that, mandatory checks on the launch vehicle and spacecraft will also be carried out. Batteries also will be charged and propellant tanks pressurized.

Risat-1, with a lifespan of five years, is to be used for disaster prediction and agriculture forestry, and its high-resolution pictures and microwave imaging could also be used for defense purposes.

India has the largest constellation of remote sensing satellites in the world, providing imagery in a variety of spatial resolutions, from roughly one meter to 500 meters, and is a major player in selling such data on the global market.

India’s 11 remote-sensing satellites are TES, Resourcesat 1, Cartosat 1, 2, 2A and 2B, IMS 1, Risat-2, Oceansat 2, Resourcesat-2, and Megha-Tropiques.

In 2009, ISRO launched the 300-kg Risat-2 with an Israeli-built synthetic aperture radar, enabling Earth observation in all-weather, day/night conditions.

The rocket that will put Risat-1 into space will be the upgraded four-stage PSLV variant called PSLV-XL, which will weigh 320 tons at liftoff. ISRO used the PSLV-XL for its moon mission (Chandrayaan-1) in 2008 and for launching its communication satellite GSAT-12 in 2011.