Why India’s Shubhanshu Shukla’s ISS Journey Takes 28 Hours? Know The Science Of Space Docking | India News

Indian Group Captain Shubhanshu Shukla underwent a historic mission to the International Space Station (ISS) as part of the Axiom Mission-4 (Ax-4). It Lifted-off from Kennedy Space Center in Florida on a SpaceX Falcon 9 rocket and Dragon spacecraft at 12:01 PM IST. Even though they are relatively near, Shubhanshu Shukla and his fellow crew members will need around 28 hours to arrive and dock the orbiting laboratory.

This longer trip is the result of a subtle interplay of technical and scientific parameters. The ISS orbits Earth at an altitude of about 400 kilometers (250 miles) in Low Earth Orbit, flying through space at a speed of 28,000 kilometers per hour (17,500 mph). Capturing such a high-speed target is a matter of precise orbital maneuvers.

Reasons For The 28-Hour Transit

Orbital Phasing Manoeuvres: The ISS maintains a specific orbit around Earth. After launch, the Dragon spacecraft must gradually adjust its own orbit to precisely match that of the ISS. This process, known as “phasing manoeuvres,” involves carefully balancing the spacecraft’s altitude and velocity through a series of thruster firings. The Dragon’s 16 Draco thrusters, each producing 90 pounds of force, are crucial for these adjustments.

Safety and Accuracy: Docking with ISS is a very complicated and sensitive operation. The spacecraft has to precisely coordinate its speed and position with the station so that a safe connection can be made. Any calculation error can prove disastrous. Thus, the Dragon slowly and cautiously approaches the ISS so that minute adjustments can be made. After the launch, another 1-2 hours are taken to stabilise the spacecraft and perform safety checks, such as checking air pressure and ensuring there are no leaks in the gases.

Dragon Spacecraft Design & Maturity: The SpaceX Dragon space vehicle is quite young, having made its first launch in 2012. As a contrast, Russia’s Soyuz spacecraft, which has been operational since the 1960s, takes only as little as 8 hours to travel to the ISS. The long history of Soyuz operations and improved mathematical models enable quicker transits. SpaceX is still refining its mathematical models for Dragon’s launch time and phasing manoeuvres, which adds to the longer transit time.

Launch Windows and Technical Delays: “Launch windows” are important in space missions – specific times in which a rocket has to be launched to effectively travel to its destination using the least amount of fuel. The Ax-4 mission has experienced several delays owing to reasons such as unfavorable weather conditions and technical complications (for example, a leak of liquid oxygen in the Falcon 9). The delays may make it even more difficult to execute the flight plan, possibly lengthening the transit time.

Staged Flight Profile: The Falcon 9 rocket flies in two stages. The first stage (booster), consisting of nine Merlin engines, boosts the spacecraft out of Earth’s atmosphere and then jettisons away to return for a vertical landing. The second stage (with one Merlin engine) then takes the Dragon into orbit. The staged process and duration needed to accomplish this proper orbital insertion also account for the longer travel time.

Journey Details

Launch: The Ax-4 mission blasted off today at 12:01 PM IST (2:31 AM EDT) from Kennedy Space Center, Florida.

Orbital Insertion: The Dragon spacecraft will insert itself into orbit within 15 minutes of launch. At this time, “Joy,” a little goose toy used as a zero-gravity indicator, will start floating.

Phasing Manoeuvres: In the 28 hours following this, the Dragon will gradually synchronise its orbit with that of the ISS with a sequence of gradual firings of small thrusters.

Docking: Docking to the ISS’s Harmony module (space-facing port) is predicted between 4:00 PM and 10:00 PM IST on June 26, 2025.

Safety Inspections & Boarding: After the docking, 1-2 hours will be spent on pressure equalization and leak inspections prior to the entry of Shubhanshu along with his crew into the ISS.

Shubhanshu Shukla’s Role

Group Captain Shubhanshu Shukla will be the pilot of the Ax-4 mission and will work in conjunction with Mission Commander Peggy Whitson. Among his duties, he will handle spacecraft operations, monitoring systems, and supporting scientific experiments. He will be aboard the ISS for 14 days, operating 7 Indian and 5 NASA-conceived experiments, and depicting Indian culture and yoga.

The multiple setbacks, originally scheduled for May 2025, highlight the enormous complexities and absolute priority of safety in space travel due to weather, technical malfunctions, and Russian segment ISS maintenance.