BENGALURU: As every science enthusiast and Indian celebrated the undocking of Dragon spacecraft Grace from the International Space Station (ISS) on Monday evening, experts and scientists from the Indian Space Research Organisation (ISRO) said the re-entry and a safe splashdown would be crucial.
“In space, the spacecraft is orbiting at speeds of 28,000 km/hour and is in zero- gravity, but when it has to start to descend, this speed will have to be reduced to 24 km/hour in less than an hour. This will be done gradually by firing thrusters in the opposite direction, which will act as brakes to reduce the speed. At this time, the spacecraft will be at an altitude of 70-80 km. The angle at which the spacecraft enters the atmosphere is vital,” explained an ISRO scientist.
The return is the opposite of the manner in which the spacecraft lifts off from Earth’s gravity. While leaving the Earth’s orbit, the friction is low, but while descending, the friction is high. The temperature of the spacecraft will increase to 1,500-2,000 degrees Celsius and at this time the heat thresholds will play a crucial role. There should not be any leaks in the spacecraft during angling, which is the most important to ensure the safety of all the astronauts, the scientist explained.
“The exercise to descend and reduce the speed will start at 2 pm. A few minutes before the splashdown in the Pacific Ocean, off California coast at 3pm, the drogue parachutes – which are smaller parachutes used to stabilize the space capsule tumbling towards Earth – will open, after which main parachutes will open to cushion the splashdown impact. At the atmospheric re-entry, a tentative angle of 40 degree is expected, however, it changes depending upon the location and other parameters,” explained an expert.
Experts explained that soon after a safe landing, the astronauts will be removed from the hatch side of the spacecraft and taken to the anchored ships for immediate medical attention. Their health parameters are examined by a team of highly trained medical experts, following which they are airlifted to their designated location of quarantine and medical attention.