In the year 2016, India came up with its very first navigation satellite which was named as Indian Regional Navigation Satellite System (IRNSS-1A). Later, it was discovered that, the satellite had issues with rubidium atomic clock. After two of the atomic clocks got failed, ISRO faced loss and lost the deal.
Since the design and components were foreign for the ISRO team, the atomic clocks proved to be a fail and could not be repaired by the team.
Since then, nine out of the 21 clocks faced the failure mechanism. This served as a major setback in satellite launching. Resultantly, India’s plans for regional GPS seemed like a failed attempt, just because of non-stop failures of the atomic clocks.
As a result, ISRO decided to make its own atomic clocks. This indigenous plan will provide ISRO a complete control over its satellite launch mission.
“We are in the process of getting approval [from the government] for at least another four IRNSS satellites,” ISRO Chairman K. Sivan mentioned.
Also, Tapan Misra, Director of Space Applications Centre (SAC), Ahmedabad, mentioned that “SAC has developed an indigenous atomic clock, and this clock is currently undergoing a series of qualification tests. Once it successfully clears all tests, the desi atomic clock will be used in an experimental navigation satellite to test its accuracy and durability in space.”
Another question that sprouts a curiosity is that if atomic clocks are hard to make and can easily breakdowns, why do engineers insist on them? Can’t a regular quality wristwatch do the job?
Here is a simple answer, ‘No’.
This is because:
Regular watches run on an error gap of 10-20 seconds in a month. On the other hand, atomic clocks are more accurate and run on an error of 1 second in 100 million years which is just negligible.
This makes a huge difference as GPS receiver lacks on accurate time signals as the time signals vary from GPS satellite. This information is used to calculate the exact position on earth. If the clock differs even a little, the person may miss the next left turn by 100 meters.
Hence, the atomic clock makes the mission a lot more important than we can imagine.
On contrary to an earlier time, when we kept the time track by looking at the sky, these days, we do that by into the atoms.
Atomic Clock works on Electron Transmission Concept
Atomic clocks work accurately by deriving the time from cesium (Cs) and rubidium (Rb) atoms. The atoms of these two elements hop among two atomic states.
In a nutshell, when atom slides from high energy to lower energy state, energy is emitted. The amount of energy spilled is the amount of light it produces. Atomic clock works by calculating the frequency of this emitted light. This procedure works in a clock, because the difference in energy is always constant. For caesium element, almost 9,19,26,31,770 frequency makes 1 second. Atomic clock measures this frequency to keep up with the time and gives the highest amount of accuracy.
SAC director also mentioned that “With the development of the desi atomic clock, ISRO has become one of the few space organizations in the world that have gained the capability to develop this highly sophisticated technology. We don’t know the design and technology of the imported atomic clock. But the desi clock has been developed based on our designs and specifications. This clock is as good as the imported one. We are hopeful that it will easily work for more than five years.”