CHENNAI/NEW DELHI: Soon after Indian Space Research Organisation (Isro) chairman K Sivan reiterated on Saturday that Chandrayaan-2 was 98% success (citing the orbiter), some senior scientists have challenged the claim, one of them posting on social media his thoughts on leadership and rocket science.A senior space scientist said such claims “without any deep introspection make us a laughing stock in front of the world”. Isro sources said Vikram, the Chandrayaan-2 lander, probably crashed at great speed and was lost forever. Moon landing was the stated highpoint of the mission.The talking point on Sunday was a social media post by Tapan Misra , adviser to the Isro chairman, who took a dig at Sivan’s leadership without naming him. “Leaders inspire, they do not manage,” wrote Misra, who was moved out of the post of director of Space Applications Centre , Ahmedabad, after Sivan took over as Isro chairman.“When you see a sudden spurt in emphasis on adhering to rules, sudden increase in paperwork, frequent meetings, winding discussions, you surely know leadership is becoming a rare material in your institution. Institutions do not evolve with time as they stop innovating. Ultimately, they become living fossils, footnotes in history,” read the post.A space scientist with expertise in moon missions told TOI on condition of anonymity there were technical mistakes in the mission. “Had Isro gone with a single thruster rather than five thrusters, the technology would have been simpler and easier to handle. This is a conventional configuration being followed across the world.”