# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DXE1Rz4gLGa
- **Gondola URL:** https://gondola.cc/posts/64172359-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/4fcfad4439.jpg
- **Posted:** 2026-04-13T14:40:01.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

When astronauts return to Earth, they don’t simply “come down”—they slam into the atmosphere at orbital speeds of ~7.8 km/s (about 17,500 mph). At those velocities, air can’t move out of the way fast enough, so it compresses violently in front of the spacecraft.

That compression drives temperatures up to ~1,500–3,000°C around the vehicle. Contrary to popular belief, it’s not friction that causes most of the heating—it’s the formation of a superheated plasma sheath as atmospheric gases are compressed and ionized. This plasma glow is what you’re seeing during re-entry.

To survive this, spacecraft use thermal protection systems (TPS):
	•	Ablative heat shields (like those on Apollo capsules) that char, melt, and carry heat away
	•	Reusable tiles (like the Space Shuttle) that insulate against extreme temperatures
	•	Modern materials (like SpaceX Dragon’s PICA-X) designed for high efficiency and reusability

Astronauts also experience intense deceleration forces—up to ~3–5 g depending on the profile—as the spacecraft trades kinetic energy for heat and drag. Flight computers precisely control the angle of attack to avoid skipping off the atmosphere or burning up.

For a few minutes, communication with mission control can even drop out due to the ionized plasma blocking radio signals—known as a “blackout.”

Re-entry is one of the most dangerous phases of any mission: a balance between physics, materials science, and precision guidance.

What part of re-entry surprised you most? Comment below, and share this with someone who thinks it’s just “falling back to Earth.”

#STEM #SpaceScience #Astronauts #Physics #Aerospace

Sources: NASA (Thermal Protection Systems, Re-entry Physics), ESA (Atmospheric Entry), SpaceX (Dragon TPS materials)

## Stats

- **Views:** 4,951
- **Likes:** 253
- **Shares:** 0
- **Comments:** 19

## Tags

stem, astronauts, physics, spacescience, aerospace

---
Copyright (c) Gondola