Group Captain Shubhanshu Shukla, the 39-year-old Indian Air Force pilot turned astronaut, reminisced on the launch in his first call from space. He has described the experience as “indescribable.” Astronaut Shukla and his team will perform scientific tasks for the next 14 days in the International Space Station (ISS). Mr Shukla also said, “I was not feeling well, and I was very sleepy when we were launched into the vacuum. Learning how to walk and eat in space like a child.” The #Ax4 crew—commander Peggy Whitson, @ISRO astronaut Shubhanshu Shukla, @ESA astronaut Sławosz Uznański-Wiśniewski, and mission specialist Tibor Kapu—emerges from the Dragon spacecraft and gets their first look at their home in low Earth orbit. pic.twitter.com/5q0RfoSv4G Effect of Spaceflight and Zero Gravity on Human Body NASA’s Human Research Program (HRP) has been researching the effects of space travel on the human body for over 50 years. Knowing how spaceflight affects people is important when astronauts travel from the low-Earth orbit of the International Space Station to deep space locations on and around the Moon and beyond. A Mars expedition will expose astronauts to three distinct gravitational conditions. Crews living and working on Mars will experience gravity that is about one-third that of Earth. Crews will be weightless for the six-month journey between the planets. Changing from one gravity field to another is more difficult than it seems. Space motion sickness affects several crew members, making it difficult for them to move, balance, coordinate their hand-eye and head-eye movements, and maintain spatial orientation. After returning home, personnel will eventually need to adjust to Earth’s gravity. According to NASA , weight-bearing bones lose between 1 per cent and 1.5 per cent of their mineral density each month while in space, yet the human body is not affected by Earth’s gravity. Rehabilitation may not fully restore bone loss after returning to Earth, but their risk of fracture is reduced. In addition, the fluids in the body move upward towards the head under microgravity, which could strain the eyes and impair eyesight. Crews may have a higher risk of kidney stones if prophylactic or countermeasures are not taken because of dehydration and increased calcium excretion from their bones. Spinal ultrasounds are used to track back pain, which some astronauts reported experiencing while in space. Bone density and muscle size are assessed for deterioration both before and following spaceflight using MRI and high-resolution imaging techniques. Periodically, crew members assess their fitness levels to assist researchers in better understanding how spaceflight can cause a deterioration in heart function. Moreover, astronauts lose muscle mass in microgravity more quickly than they would on Earth if they fail to adhere to a healthy diet and exercise regimen. Astronaut Shubhanshu Shukla and three other astronauts are on the Axiom Mission 4, which was launched from Florida. The space mission is scheduled to run for 14 days. Track Latest News Live on NDTV.com and get news updates from India and around the world