Knowledge Booster: NASA, Sunita Williams, SpaceX Return, and Gaganyaan

Why in the News?

• NASA astronaut Sunita Williams and Butch Wilmore returned to Earth after a prolonged stay on the International Space Station (ISS) due to propulsion issues with the Boeing Starliner spacecraft.

• Their return journey was aboard SpaceX’s Dragon spacecraft.

Key Takeaways

1. Starliner Spacecraft:

   • Boeing-built spacecraft designed to transport people to and from low-Earth orbit (LEO).

   • Developed in collaboration with NASA’s Commercial Crew Program.

   • Can accommodate up to seven passengers or a mix of crew and cargo for LEO missions.

   • Reusable up to 10 times with a six-month turnaround time.

   • Return journey to Earth was initially scheduled for June 26 but was postponed due to issues detected in some key mechanisms required for a safe flight.

2. SpaceX’s Crew Dragon:

   • Partially reusable variant of SpaceX’s Dragon 2 spacecraft.

   • Crew Dragon primarily transports astronauts to the ISS.

   • Cargo Dragon supplies cargo to the space station.

   • Crew Dragon’s first mission to the ISS took place in 2020, transporting four American and Japanese astronauts.

   • Consists of a reusable space capsule and an expandable trunk module.

   • Launched into space atop a Falcon 9 rocket and docks automatically to the ISS.

3. SpaceX’s Falcon 9:

   • A partially reusable rocket designed and manufactured by SpaceX.

   • Can transport crew and payloads to low Earth orbit (an altitude of 2000 km or less) and beyond.

   • Two-stage rocket:

     • First stage: Nine Merlin engines, aluminium-lithium alloy tanks containing liquid oxygen and rocket-grade kerosene propellant. Reusable and capable of vertical landing.

     • Second stage: Single Merlin engine.

4. Space Anaemia:

   • Condition observed in astronauts during and after extended space missions.

   • Primarily due to the body’s adaptation to the unique environment of space.

   • Microgravity leads to significant fluid shifts, impacting blood volume and red blood cell production.

   • Reduction in overall blood volume can result in lower red blood cell counts and decreased haemoglobin levels.

5. Impact of Space Travel on Astronauts:

   • Physiological changes due to prolonged exposure to microgravity, radiation, and isolation.

   • “Baby Feet”: Loss of calluses on the feet due to the absence of air and gravity, leading to thinner skin.

   • Bone Density Loss: Irreparable bone density loss due to the absence of gravity.

     • Weight-bearing bones become about one percent less dense for every month spent in space.

     • NASA states that for every month spent in space, the weight bearing bones of astronauts become about one percent less dense, if proper precautions are not taken.

   • Cosmic Radiation and DNA Damage: Increased exposure to cosmic rays and solar radiation, which can penetrate the body and damage cellular DNA. Microgravity compromises the body’s ability to repair damaged DNA.

India’s Gaganyaan Mission

1. Announcement: Announced in 2018.

2. Objective: Demonstrate human spaceflight capability by sending a crew of 3 members to a 400 km orbit for a 3-day mission and safely returning them to Earth by landing in the Indian sea waters.

3. Exclusive Club: Only the United States, Russia, and China have executed human spaceflight missions so far.

4. Challenges: Sending humans into space and bringing them back safely is more expensive and challenging than Mars and Moon missions.

5. ISRO Goals:

   • Short-term goal: Demonstrate human spaceflight to Low Earth Orbit.

   • Long-term goal: Lay the foundation for a ‘sustained Indian human space exploration programme’.