Space to Learn

However, in the terminal stage, there was malfunctioning of a sensor, which led to the satellites being placed in an elliptical orbit instead of a 356 km, low-Earth, circular orbit. An elliptical orbit is defined by its long and short axes, just as a circle is defined by its radius. The short axis of the elliptical orbit achieved was small and the height the satellites were above the earth was only about 76 km. At this height, the atmospheric drag would hinder the progress of the satellite and if a huge thrust is not provided, the object would lose height and fall back to the earth, perhaps burning up; in any case it will be invariably lost to the control room. This is what happened to the two satellites being carried by the SSLV.

The SSLV has been promoted as the next workhorse rocket of ISRO after the Polar Satellite Launch Vehicle (PSLV). Measuring just two metres in diameter and with a height of 35 m, it is indeed smaller than the PSLV which has been used to place satellites of a wide range of masses. The fact that PSLV carries smaller satellites, too, is something of an overkill, and those with masses up to 500 kilograms can be sent up using the SSLV instead. The SSLV uses solid propellants and this is more economical and easier to handle than the liquid propellant stages of the PSLV. The SSLV has the flexibility to launch multiple satellites, and satellites can be launched on demand — as the rocket requires minimal launch infrastructure. All these features make it very attractive for commercial earth observation and communication. Strategically, too, it makes sense to separate the ranges of mass being carried. This time, however, success was not to be, and the 135 kg Earth Observation Satellite EOS-02 and the 8 kg nano satellite, AzaadiSAT, were both lost. What stood out in this episode was the direct communication of S. Somanath, Chairperson, ISRO, and making available the initial analysis quickly for the benefit of all concerned. It is well known that space agencies around the world invest in testing much more than India does. India’s approach, though seemingly economical, might extract a cost at some point. Success in such circumstances is remarkable; and failure a lesson that comes at a cost.