Why Ocean Landings are Vital for the Safe Return of Spacecraft ,Most US launch pads are on shore. (Think Cape Canaveral.) But have you ever wondered why, for more than a decade, spacecraft returned to water too?
Splashdown, the term for landing capsules or other spacecraft in a body of water using parachutes, was NASA’s preferred method before the invention of the space shuttle. Now, in the age that follows it, we may be reconsidering descents as the best way to bring astronauts home safely.
Here’s everything it includes.
Splashdown Mechanics: Aerbreaking
On re-entry, the spacecraft must slow down from an initial speed of somewhere around 17,000 miles per hour to… well, a speed that the astronauts on board could sustain when they hit the planet’s surface.
Nowadays, by the time a space capsule actually splashes into a body of water, it travels at a relatively leisurely speed of about 15 to 20 mph. To begin slowing things down, NASA is turning to a technique called air suspension. Basically, the spacecraft intentionally touches the upper atmosphere of the Earth, just enough to create friction.
The giant parachutes you might already associate with descents don’t actually come into play until the final leg of the flight—when the craft is less than 10,000 feet above the surface. If they are located too high in the atmosphere, the thin air creates problems.
Early mercury flights, after a successful ocean dive, a helicopter will attach a cable to the capsule and place it safe and sound on a nearby ship. Later, the capsules were equipped with a flotation collar; this helped prevent them from sinking while they waited for a crane to lift the ship and crew aboard.
The recovery craft for the Apollo 13 mission lifts the command module aboard the craft in 1970 (Credit: NASA/Public Domain)
Read more: How reentry heat helps spacecraft return to Earth
Pros of Splashdowns
All US space capsules before the reusable space shuttle – which landed on the runways as a commercial aircraft – chose to land rather than dry land.
On the one hand, this made sense: since the launch sites are coastal, the space capsules were already designed to survive a water emergency landing in the event of an accident during launch.
Plus, water makes for a much softer landing pad than… well, land. Parachutes alone would not be enough; while Russian and Chinese manned space capsules used heavy brake rockets to slow their final descent and return to dry land, NASA wanted to avoid all that extra weight.
And, of course, if you land in the ocean and find that your calculations are off by a few miles — don’t worry. There’s a lot of wiggle room.
It’s a much different story in the continental United States, which is dotted with canyons, towns and preserves even in the most remote deserts.
Cons of Splashdowns
On the downside, the empty, open ocean comes with its own problems. At one point, locating and securing the capsules after the crash required the coordinated efforts of multiple Navy ships—not to mention millions of dollars.
In 1962 for example Aurora 7 exceeded the intended landing area by a full 250 miles. Astronaut Scott Carpenter waited three hours in a life raft before, wet but happy, an HSS-2 helicopter picked him up.
Even when the landing site is correct, other things can still go wrong.
Both the Skylab 4 mission and the Apollo-Soyuz test project ended with capsized space capsules. Although the inflatable “righting spheres” eventually straightened the upside-down Apollo-Soyuz capsule, crew member Vance Brand actually passed out before doing so.
Perhaps the most dangerous aspect of falling in a flood, however, is the potential for flooding—and submergence. This was illustrated in 1961 when hatch of Liberty Bell 7 he breathed mysteriously prematurely and almost caused the drowning of astronaut Gus Grissom.
The capsule itself, a grim reminder of the event, remained under the Atlantic Ocean for 38 years.
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NASA Splashdowns today
The Orion spacecraft crashed into the Pacific Ocean on December 11, 2022 (Credit: NASA/Kim Shifflett)
The modern era of landings was ushered in by SpaceX—and, thankfully, today’s landings, such as the Orion landing, are far less risky than their predecessors.
On August 2, 2020, two NASA pilots boarded the SpaceX Dragon capsule back to Earth, landing about 40 miles off the coast of Pensacola, Florida. This marks the first NASA astronaut landing since Apollo-Soyuz test project 45 years ago; it was also the first ever manned spacecraft landing in the Gulf of Mexico.
Orion Splashdown
No crew Orion Scatteringthe finale of Artemis I flight test, was also a big success in late 2022. After a 25-day trip around the moon, the Orion capsule hit Earth’s atmosphere at nearly 25,000 mph and at scorching temperatures of nearly 5,000 degrees Fahrenheit—about half as hot as the surface of the sun. according to NASA.
However, using a new maneuver called an “entry jump” in which the capsule entered the upper atmosphere of the Earth not once, but twicethe parachute-clad Orion drifted toward the Pacific Ocean at a remarkable 20 miles per hour.
Now the preparation for Artemis II is in progress. The mission aims to put men on the moon for the first time since 1972 – and send them home with a splash. In February of this year, a recovery team including NASA divers began training to get the Orion capsule out of the water again.
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