Isro launches EMISAT and 28 other satellites from US, Spain.

Isro has launched the EMISAT satellite along with 28 other satellites from other nations. The EMISAT will conduct space experiments.

Days after India tested its first anti-satellite missile, Indian Space Research Organization (ISRO) has fired off a new variant of its old workhorse, PSLV sending 29 satellites into three different orbits in space.

The Polar Satellite Launch Vehicle (PSLV) which is on its 47th flight took off from Satish Dhawan Space Centre, Sriharikota at 9:27 am, on Monday. The new variant uses four strap-on motors.

PSLV C45 carries 28 foreign satellites, 24 from United States which are mostly for earth observation, two from Lithuania and one each from Switzerland and Spain. All the foreign satellites would be injected into the low-earth orbit, at an altitude of 504 kms above the earth’s surface.

The primary satellite onboard is India’s EMISAT, an observation satellite which weighs 436 kgs and would measure the electromagnetic spectrum to help locate positions of enemy radars.

After removing the heat-shield at an altitude of 115 kms, the fourth-stage of rocket (PS4) would first inject EMISAT into an orbit of 749 km. It would then fire its engines twice and come down to an orbital of 504 kms where all the foreign satellites together weighing about 220 kg would be released.

The fourth stage would then eventually come down to 485 kms orbit, where it will act as an orbital platform for three other payloads - ISRO’s Automatic Identification System which would help in automatic identification of ships by capturing messages from ships and relaying them to ground stations.

The other two payloads include - an Automatic Packet Repeating System from Radio Amateur Satellite Corporation(AMSAT) to assist amateur radio operators in tracking and monitoring position data and an payload from Indian Institute of Space Science and technology (IIST) for study of structural and composition of ionosphere.

It is the first time that scientists have equipped the fourth stage with a solar panel so that it can sustain itself by generating electrical power in orbit.

The decision to use PS4 as an orbital platform was one of the several firsts marked by the space agency this year. Since, the fourth stage of the rocket becomes debris after it takes a satellite into its desired orbit, the idea was to innovatively use this wasted stage for payloads and conduct experiments in space.

It would also enable space researchers to study earth’s ionosphere in real time which can help in improving accuracy of satellite navigation signals.

The previous launches by ISRO this year include the imaging satellite Microsat-R for military purpose along with 1.2 kg Kalamsat in January onboard PSLV-C44.

In February, Isro launched India's communication satellite GSAT-31 from the European launch service provider Ariane from French Guiana.(Source:Livemint)