Dr. Vikram Sarabhai, widely regarded as the father of the Indian space program, was Dr. Kalam's mentor and guide at ISRO. Sarabhai recognized Kalam's potential and guided him in rocketry and space research. K. R. Narayanan was a future President, while Aryabhatta was an ancient mathematician. 'Avul' refers to Kalam's own family name, not his great grandfather.