What is the mood in the
Every space mission is a challenge, whether it is the launch of a rocket or a satellite operation in orbit. This, especially, is important because it is much more complex than anything we have undertaken so far. The Polar Satellite Launch Vehicle (PSLV) C25 is the 25th launch of the PSLV and in the XL configuration, this will be the fifth launch. Even then, the mission here is different in the sense that the satellite has to be injected into an elliptical orbit which calls for a unique trajectory and flight duration of nearly 43 minutes. That is one part. The second part is the 1,350-kg Mars Orbiter spacecraft which incorporates certain unique aspects into the Mars mission.
What are these unique
We are talking about a long voyage and the great distance between the ground station and the orbiter when it is in the orbit of Mars, which means there will be a communication delay to the extent of 4 minutes to 20 minutes one-way. So we have to incorporate a certain level of autonomy in the spacecraft for it to manage itself till the ground controllers are able to understand any problem in the components of the system and give the corrective commands. Then, our ability to compute the position of the spacecraft where it will be before the Martian orbit insertion in September 2014 while leaving the Earth orbit on November 30, 2013 itself. When you talk about any mission to Mars, it can be done only in opportune windows. So time is of the essence, but the most satisfying part of it is the ISRO team has made it, having been working on a 24/7 basis to realise this.
What have been some of the key challenges
The sphere of influence of Earth is generally understood because we had done this in Chandrayaan (the moon mission in 2008) . But at that time we went upto 400,000 km and in this case the sphere of influence of Earth is nearly 925,000 km. We are going then through a long phase of travel of nearly 780 million km during which the spacecraft is influenced by the Sun and all the planets. We have had to understand the influence of each of the planets. This is something new and complex. When it comes closer to Mars, called the sphere of influence of Mars which is nearly 600,000 km, there again we have to understand the influence of the Sun, Mars and the moons of Mars. We have benchmarked with calculations done by NASA which has had several missions to Mars. Now, wouldnt the Geosynchronous Satellite Launch Vehicle (GSLV) have been a better vehicle and why did we choose such as elliptical orbit There are two reasons. The GSLV certainly can put a heavier satellite into an elliptical orbit or this satellite into a larger orbit, which means the initial operations can be slightly shorter. But PSLV is a vehicle with proven reliability with 23 successful missions whereas, with the GSLV, our experience has been 50/50 in its 7 flights so far. But we have not reduced or removed any payload that was available. All the payloads that were made ready by our scientists have been used.
Were there only five instruments to start with
Only five were available and all of them have been taken. So nothing has been lost in terms of scientific instrumentation because we have gone for a PSLV. But we have a more reliable vehicle. And when we go for such a major mission, certainly a vehicle with better reliability is a prudent decision.
How will all this help ISRO with future missions
This is our first interplanetary probe. If this mission is successful, that means we have been able demonstrate the technological capability and make some contribution to science.
However, since this is a very complex mission, every days progress is an understanding. It can pave the way for another major mission to understand Mars in 2016, 2018 or 2020 which are the windows that are open with a good scientific objective. And Mars is certainly a planet which requires more understanding. Besides, many of the complex technologies that we have brought into the spacecraft systems are useful and certainly will find a place in the future satellites that we are going to build for communication and remote sensing and other applications. So this is the indirect advantage.