4 Reasons Why Space Probes Enter the Atmosphere or Land

by Carson

Some space probes enter the atmosphere, impact, or land on a celestial object. Here are 4 legitimate reasons and how to allow a spacecraft to survive landing or atmospheric entry.

1. Returning Crew to Earth

The most apparent reason to land a space probe is to get the astronauts unstuck. After all, they need to go back to Earth after a long voyage into outer space! If astronauts stay in space forever, they will feel extremely isolated, and the lack of gravity will cause problems in their bodies.

While being the most necessary one, it’s the one that requires the most precision. For a robotic mission, any mistake during atmospheric reentry or landing will only doom the robot. However, the same thing on a manned mission can signal the death of all crew members inside the capsule.

2. Landing Robots for Exploration

Other than landing humans, space agencies land robots, too. They can provide much value to space exploration and can reach territory that humans can’t.

Robots have instruments that must survive the landing, so they need a lot of protection. It doesn’t matter if the spaceship is dead after touchdown as long as the crew members are alive. It’s pointless for a space capsule to carry instruments that can be used after returning to Earth. However, the robots need certain sensors to investigate the environment around it and unlock mysteries.

3. Preventing Contamination of Moons

This is quite interesting: Both the Galileo spacecraft and the Cassini spacecraft has plunged into the atmosphere of the planet it’s exploring.

Some of Jupiter and Saturn’s moons have the potential for life, which is a key part of future space exploration. No one wants life on these natural satellites to be life brought from our planet, right? That would create huge disappointment and possibly the loss of an entire moon as the base to explore the Solar System’s origins.

Why don’t we leave it in an orbit that doesn’t touch its satellites? Well, it’s hard to predict that in the long run. There are many uncertainties in the orbit of a spacecraft, such as gravity assists from the planet’s moons. What’s worse, the space probe won’t be able to maneuver itself to another orbit once it has run out of fuel. That means the orbit cannot be modified artificially.

Therefore, it’s better to let the spacecraft burn up in the atmosphere when it reaches the end of its mission rather than letting it drift in an orbit that can potentially collide with the planet’s precious moons. On the other hand, they can collect valuable data of the planet’s atmosphere, which can be more accurate than ever before.

4. Reducing Space Debris

Last but not least, another reason for an atmospheric reentry or landing is to reduce space debris. Imagine that all of the defunct satellites are still in orbit around Earth! The place will be more and more crowded as more satellites launches until space travel becomes impossible.

Therefore, we need to get rid of the satellites at the end of its mission. We can use the remaining fuel to put it into a heliocentric orbit. However, this is not quite viable as they can return to Earth soon. For instance, an “asteroid” discovered in 2020, which orbited Earth temporarily, turned out to be a Centaur upper stage in the 1960s.

If we want to get rid of it altogether, we need to burn it up in the atmosphere. This is not applicable for rocket stages as they are large enough to survive the atmospheric entry. So, only satellites which still have some fuel left apply in this situation.

How do Space Probes Enter the Atmosphere Safely?

Well, this process varies depending on the purpose of the atmospheric entry. If you want to throw away the spacecraft, the probe does not need a heat shield. Just insert that entire probe into the atmosphere, and it’ll burn up (unless it’s large enough or has a heat shield).

However, you have to get into the atmosphere. In that case, the spacecraft needs to fire its engines to lower its orbit until its periapsis reaches the atmosphere or below the planet’s surface.

If you want the space probe to land safely after entering the atmosphere, it’s pretty hard. Firstly, the spacecraft needs a heat shield to compensate for the heat on atmospheric entry. It’s moving so fast that the friction heats up the capsule to thousands of degrees.

After that, you need a parachute to slow down the descent. However, if the atmosphere is too thin like Mars, it also needs rockets to further decelerate the lander until it touches down at a slow pace so that it doesn’t damage the space probe.


Here are 4 reasons why space probes enter the atmosphere and how to do so correctly. Can you think of any other reasons? Let us know in the comments.

References and Credits

  1. (2019, May 8). 5 Hazards of Human Spaceflight. Retrieved March 30, 2021, from https://www.nasa.gov/hrp/5-hazards-of-human-spaceflight
  2. Fedor Kossakovski. (2017, September 13). Analysis: Why NASA’s Cassini probe had to be destroyed. Retrieved March 30, 2021, from https://www.pbs.org/newshour/science/analysis-nasas-cassini-probe-must-destroyed
  3. Primal Space. (2021, February 19). The Mysterious Return Of NASA’s Centaur Rocket – YouTube. Retrieved March 31, 2021, from https://www.youtube.com/watch?v=NLKvK_S5StE

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