Russian spacecraft expected to survive death plunge to Earth later this week

Sometime during the second week of May, a 53 year old Soviet era spacecraft — originally designed to land on Venus — is predicted to come crashing back to Earth. There's a good chance it won't entirely burn-up and the remains may make it all the way to the surface of our planet. Re-entry is currently forecasted for May 10th.

Kosmos 482 was launched from the former Soviet Union in 1972 on a course that was supposed to take it to Venus. But a failure of the upper-stage rocket booster left it in an elliptical orbit around the Earth, where it has remained for more than half a century. Over time, the orbit has decayed and now the defunct probe will return home.

Exactly when and where the impact will occur will not be known until just hours before it enters the Earth's atmosphere, but it will fall between 52 degrees north and 52 degrees south latitude, which covers an enormous proportion of the most densely inhabited parts of the world.

The part of the spacecraft expected to make it all the way to the ground is the half-ton spherical landing capsule which was designed to survive some of the harshest conditions in the solar system.

Venus is sometimes referred to as our sister planet because it is in some ways similar to the Earth: a rocky world about the same size and with a thick atmosphere covered in clouds.

But that is where the similarity ends. The surface of Venus is a planetary hellscape with a thick atmosphere made of carbon dioxide, dense clouds of sulphuric acid and temperatures at the surface above 460C. In other words, landing on Venus is like drifting down through battery acid, then touching ground hot enough to melt lead. The crushing atmospheric pressure may be 75 to 100 times greater than that on Earth.

Any spacecraft designed to land on Venus must be strong enough to survive that hellish environment. The Soviet Union is the only country to land on Venus with eight landers called the Venera missions.

These spacecraft were built like deep-sea submersibles, with thick spherical shells about a metre in diameter able to withstand the atmospheric pressure, protect against the corrosive atmosphere and provide cooling for the scientific instruments.

Venera 7 became the first spacecraft to transmit data from the surface of another planet when it touched down on the surface in 1970 despite a ripped parachute. It survived for 23 minutes before succumbing to those harrowing conditions. 

The longest time spent working on the surface was 127 minutes by Venera 13 which also sent back the first colour images of the scorched barren landscape under a brownish sky.

Kosmos 482 was also designed to survive plunging into the thick hot atmosphere of our sister planet, which is why it has a good chance of making it through Earth's much thinner and cooler air. 

Newly published images show an elongated structure that might be the landing capsule's exposed parachute. If that is the case, it'd likely burn up upon re-entry and have no effect on slowing the spacecraft down.

Even if the parachute hasn't deployed, experts think it's unlikely to do so on the way down because any instruments to measure altitude or pressure as well as triggering mechanisms to release the chute are expected to be long dead after more than 50 years in space. That means atmospheric drag would slow it down to about 240 km/hr all the way to the ground.  

If the capsule lands in water, which is the most likely scenario since most of the Earth's surface is ocean, it could remain intact. Whether it floats or not is uncertain.

We can hope it won't come down on a building or crowded street, but if it does, it would not be expected to cause a huge crater in the ground. If it doesn't completely burn up, it would be interesting to study the remains to get a glimpse into Soviet-era technology and see the effects of long exposure to materials in space.

When we get closer to its expected re-entry date and it looks like it could be coming down in your area, look for a bright streak in the sky, even visible during the day, then listen for the sound of a thumping crash, hopefully not too close to where you are standing.