On October 11, 2018, a Russian Soyuz rocket was launched from Kazakhstan with a two-member crew.
The rocket was intended to be sent to fix a small problem with the International Space Station. However, after just 90 seconds, the unexpected happened.
Somehow, the booster rocket failed, and a capsule with the crew was forced to eject and return to the surface through ballistic reentry. Fortunately, the crew of astronaut and cosmonaut survived, but future flights have been suspended for the time being.
What Are Booster Rockets?
Booster rockets are fuel boosters that help the spacecrafts escape Earth’s orbit.
During the first stage of takeoff, the boosters provides fuel to initially propel the rocket upward into the sky. Once the booster rockets exhaust their fuel supply, they separate from the carrier rocket. Then, the booster opens up a parachute and comes splashing into the ocean if everything goes to plan. Unfortunately, booster failures have occurred several times in the past; for instance, the Challenger exploded due to holes in the boosters.
These booster rockets were the reason why the Soyuz MS-10 launch failed. After running out of fuel, the boosters failed to detach properly, forcing the crew onboard to eject.
Ideally, the crew would separate the capsule they are in from the rocket, and use another smaller rocket to steer themselves back to Earth. That was not the case for Soyuz, as it was forced to return to the Earth in a ballistic descent.
What Is Ballistic Descent?
The Soyuz capsule fell down to the surface at a rather steep angle. The crew onboard experienced a G-force (gravitational force) that is estimated to be 10 times the amount people standing on Earth feel!
Ballistic descent uses the atmospheric drag to slow down the spacecraft - in other words, the atmospheric air resistance pushes up against the falling rocket. Normally, astronauts would only go through this steep and short journey when they reenter the Earth’s atmosphere from space. For a gentler landing, the crew members could have used controlled descent to slow down the capsule at a more gradual angle over a longer period of time. Unfortunately, they were not able to and had to use ballistic descent to land.
Nevertheless, the capsule landed, and the crew was rescued unharmed. The incident will definitely impact future space decisions such as checking future flights and fixing the International Space Station.
Sources: Space.com, Newscientist, NASA, popsci, rferl, Wikipedia