Isro performs orbit raising manoeuvre today

A day after successfully launching India’s Mars Orbiter spacecraft Mangalyaan, Isro officials are now waiting for the next crucial event – the orbit raising manoeuvre.

This will take place in the early hours of Thursday.

Isro officials said there would be five firings (or orbit raising manoeuvres) of the 440 Newton engine, which is on board the Mars Orbiter PSLV C25, to gradually increase its apogee – the point of greatest distance from the Earth in its orbit. The onboard motors will be fired for around 200 seconds to raise its orbit by around 4,120 km to 28,785 km.

“Today morning (on Wednesday) we carried out the rehearsal for the orbit raising activities without switching on the motor,” said an Isro official.

Since the launch, the control of the mission has been taken over by scientists at ISRO Telemetry, Tracking and Command Network (ISTRAC) at Bangalore.

“Every day and every thing is crucial in this mission,” said a spokesperson of the Isro.

On December 1, (at 12.42 a.m) the scientists would perform a trans-martian injection and the spacecraft would start its long and difficult voyage towards Mars for almost 300 days. The orbiter is expected to land on Martian surface on September 24, 2014.

Isro Chairman K Radhakrishnan said, “It has been a new and complex mission design to ensure that we would be able to move the Mars orbiter spacecraft from the orbit of Earth to the orbit of Mars with minimum energy.”

On September 24, 2014, the engine would again be fired to slowdown the spacecraft's velocity and it would be reoriented to enter the Mars’ orbit with a per-apsis of 365 km and an apo-apsis of 80,000 km.

Radhakrishnan said there are many firsts in this mission. For example, the spacecraft itself had an unusually long trajectory more than 43 minutes. Tracking was never before an exercise. In this mission, the spacecraft was tracked at Sriharikota, Port Blair, Biak (Indonesia) and by the two ships – Nalandana and Yamuna – belonging to Shipping Corporation of India.These are stationed in the Pacific Ocean to track the spacecraft.

Radhakrishnan said the launch was originally planned for October 28 but it was postponed by a week, because the two vessels could not reach their destinations on time. After its separation from the rocket, the spacecraft will be tracked by a network which are based in Bangalore, Goldstone (US), Madrid (Spain) and Canberra (Australia).

The deep-space networks of Isro and Nasa will keep an eye on the spacecraft once it leaves the Earth's influence on December 1.

“That will be another major challenge,” said the chairman, since the spacecraft would encounter new challenges in the form of pulls of planets and the Sun, besides solar radiation.

He said once in deep space, there will be a lag of 20 minutes between sending and receiving signals from the spacecraft and earth stations. To address this challenge, Isro has to rely on autonomy, instead of relying on ground commands.

On spending Rs 450 crore for Mars mission, Radhakrishnan said, “Science and technology are needed to uplift a country and it was proved in India that space touches every human being through communication, remote sensing and several other applications launched by Isro.”

“This mission will pave way for advancement in satellite technology that would feed into application technology development programme in the country,” he said.