Sultan Al Neyadi's return to Earth: Is ocean or land more comfortable for touchdowns?

The Emirati astronaut will splash down off the coast of Florida aboard a SpaceX capsule on Monday

Lift-off from Nasa's Kennedy Space Centre in Cape Canaveral, Florida, early on March 2, 2023. AFP

The crew-6 board the Dragon spacecraft to take them to the International Space Station. Photo: Nasa screengrab

Sultan Al Neyadi's first A Call with Space video chat with the public, held at Dubai Opera on March 21. Pawan Singh / The National

Dr Al Neyadi captured an image of his hometown of Umm Ghafa in Al Ain on April 12. Photo: Sultan Al Neyadi / X

This photo from space shows The Palm Jumeirah, Jebel Ali Industrial area and residential areas in Dubai. Photo: Sultan Al Neyadi / X

Dr Al Neyadi on March 4, a day after arriving on the ISS. Photo: MBRSC

Dr Al Neyadi takes a selfie from inside the ISS. Photo: Sultan Al Neyadi / X

The eye of Cyclone Biparjoy in footage captured by the UAE astronaut on June 13. Photo: Sultan Al Neyadi

Holding small tomatoes grown on the ISS. Photo: Nasa

Dr Al Neyadi in front of the ISS cupola on March 14. Photo: Nasa

The astronaut captured a massive sandstorm sweeping across the Sahara on March 30. Photo: Sultan Al Neyadi

On April 28 he became the first Arab to perform a spacewalk. Photo: Sultan Al Neyadi / X

He captured a stunning image of the Eye of Sahara - a geological structure made up of ancient rocks - from the ISS on May 4. Sultan Al Neyadi / X

Speaking to students at UAE University in Al Ain on a live call from the ISS on May 23. Ryan Lim / The National

An image of the UAE and Oman taken by the Emirati astronaut on May 24. Photo: Sultan Al Neyadi / X

Sultan Al Neyadi called Sheikh Mohammed bin Rashid, Vice President and Ruler of Dubai, from the ISS on July 3. Photo: Dubai Media Office

Capsules returning astronauts to Earth have been landing on the ground or splashing down on water for decades.

Russians and the Chinese have relied on land touchdowns, while Americans have mostly used the sea.

UAE astronaut Sultan Al Neyadi and his three colleagues will be departing the International Space Station aboard a SpaceX Dragon capsule on Sunday, which will splash down off the coast of Florida on Monday, at 8.07am, UAE time.

Hazza Al Mansouri, the first Emirati astronaut in space, landed on flat ground in the steppes of Kazakhstan aboard Russia’s Soyuz spacecraft in 2019.

'Felt like a head-on collision'

Both methods have proven reliable, with numerous missions touching down safely on either land or water.

Earth's atmosphere helps slow down a spacecraft, with parachutes used to further decelerate

The Dragon capsule uses Draco parachutes after re-entering to decrease its speed even more, then releases larger parachutes for an ocean landing.

A Russian Soyuz carrying UAE astronaut Hazza Al Mansouri and two others lands in Kazakhstan on October 3, 2019. AFP

Russia's Soyuz also uses parachutes but also activates a braking system before touchdown to reduce impact.

Italian astronaut Paolo Nespoli flew to the ISS in 2011 and landed back in Kazakhstan.

"The soft-landing is not really soft," he said in an interview with the European Space Agency in 2013.

"You prepare for it by putting your arms against your body, not talking and being as inside your seat as you can.

"You're waiting for this soft-landing to happen, which for me felt like a head-on collision.

"When it happened, everything shook and then silence. Then I looked at my crew members and said 'welcome back to Earth'."

A SpaceX Dragon capsule splashes down in the Gulf of Mexico in May 2022. AP

'Water felt a bit softer than land'

American astronauts have been landing in the sea since the days of the Mercury, Gemini and Apollo capsules.

Like a plane, the Space Shuttle used to land on a runway.

Now, Nasa is using Elon Musk's SpaceX rockets and capsules to take astronauts to and from Earth, and eventually will be using Boeing Starliner capsules once they are ready for commercial operations.

Sea landings are slightly more comfortable because water provides an extra cushion to the capsule, reducing the need for additional braking.

US astronaut Shannon Walker said in 2021: "Landing in the water was interesting because none of us really knew what to expect but I would say from my standpoint it felt a little bit softer than landing on land.

"You spend less time under a parachute on the Dragon than you do under the Soyuz."