BENGALURU: The Indian Space Research Organisation ( Isro ), on Monday said that spacecraft parameters of Chandrayaan-2 were normal after the agency completed the third orbit-raising manoeuvre.

A successful operation that saw the onboard propulsion system burn for a little more than 16 minutes, put Chandrayaan-2 into an elliptical orbit of 276kmX71,792km, around Earth.

The space agency will perform another orbit-raising manoeuvre on August 2.

As first reported by TOI, the orbiter of Chandrayaan-2, going by its performance and parameters as on Saturday, was all set for an additional year around Moon .

The orbiter was packed with 1,697kg of propellant at the time of the launch, and it has already expended about 130kg of it for the two manoeuvres Isro conducted on July 24 and 26. As on July 28, the orbiter had more than 1,500kg of propellant remaining. Another operation on July 29 was expected to use up another 131kg of fuel.

A scientist said that a better-than-textbook launch has given the agency advantage of about 40-odd-kg of fuel. Besides, another scientist said: “Even as per the initial plan we had, additional fuel was budgeted keeping in mind some emergencies. But going by present estimates and calculations, we will have more fuel than it is needed to orbit for a year.”

Sivan had earlier said that all the manoeuvres until the separation of Vikram, the lander, will be fuelled by the propellants on the orbiter. This means that there are nine more manoeuvres before the separation, during which many more kilograms of fuel will be used up.

According to Isro’s present estimation, at the end of all Earth-bound and lunar-bound manoeuvres, the orbiter should be left with at least 290.2kg of fuel when it is in the 100kmX100km orbit around Moon (see graphic).

“This will be more than enough for it to go around Moon for two years as there will be no more big manoeuvres required,” the first scientist said. Another scientist said that the only manoeuvres after reaching the desired lunar orbit, if at all, would be minor ones.

“But, given that Moon’s gravity is not uniform unlike Earth, the orbiter needs to be kept in the correct orbit, which will require periodic intervention. If left unattended, the closest point to Moon could become very narrow. These manoeuvres will use up some fuel,” the scientist explained.

All the scientists emphasised that they could only confirm the exact number of additional days the orbiter could have around Moon once the lunarcraft is settled into an orbit there. “Chandrayaan-2 is expected to be inserted into the lunar orbit on August 20, and we can assess how long it would last once it is there and we know exactly how much fuel is left,” one of them said.



In Video: Chandrayaan 2 now three steps closer to the Moon, tweets ISRO