Space debris re-entry and the meteor community

Credit: Me :D

Space debris re-entry and the meteor community

Daniel Kastinen Johan Kero Juha Vierinen Et al.

Credit: Me :D

Meteors and space objects

This is my topic at IRF

Meteors and meteoroids
Near-Earth objects and comets
Artificial resident space objects

I actually work around 50/50 on natural vs artificial objects

Because there is a lot of synergy

Meteors and space objects

Adjacent and slightly overlapping populations

Meteoroids

~10 - 72 km / s
$10^{-9}$ - $10^{2}$ g
Silicates and organics to iron
Deep trajectories
Majority of influx
Steady-ish population

Artificial space objects

~8 km / s
$10^{-1}$ - $10^{6}$ g
Batteries to alloys
Shallow trajectories
Still small influx
Massive changes ongoing

What is space debris?

2020 model distribution, Credit: ESA - Time to act

What is space debris?

ESA - Time to act

Launch vehicles/rocket bodies
Fragmented/destroyed spacecraft
Non-functional artificial objects
Ablated/lost debris (Paint flecks, nuts and bolts, ...)
Nuclear reactor cooling
...

Artificial space objects

From: ESA Space Environment Report 2025

Artificial space objects

From: ESA Space Environment Report 2025

Artificial space objects

Some back of the envelope mega-constellation calculations:

Starlink plan: 12 000 - 34 400 satellites in orbit
Design lifetime: 5 years
v1 ~260 kg, v2 mini ~800 kg
$\Rightarrow$ Launch rate / de-orbit rate =
= 2 400 - 6 900 satellites per year
= 1 900 - 5 500 tonnes per year
= 5 - 15 tonnes per day
Current numbers: ~8 000 satellites

Artificial space objects

Some back of the envelope mega-constellation calculations:

But how much gets injected into the atmosphere?

Anthropogenic input into atmosphere

From: Schulz, L., Glassmeier, K.-H., Advances in Space Research, 2021.

Artificial space objects

Anthropogenic input into atmosphere

From: Schulz, L., Glassmeier, K.-H., Advances in Space Research, 2021.

Artificial space objects

Anthropogenic input into atmosphere

They also estimated element-wise injection, have a look at their paper!

From: Schulz, L., Glassmeier, K.-H., Advances in Space Research, 2021.

Artificial space objects

We know why to care about satellites

Why care about space debris?

Artificial space objects

18 cm aluminium slab
1.7 g aluminium sphere
Impact velocity 6.8 km/s
Orbit velocity ~8 km/s
Typical collision velocity ~8-12 km/s

So even small objects are dangerous

Artificial space objects

So where do we stand?

Need more observations while in orbit and during re-entry
(current instruments have a hard time keeping up)
Need to observe smaller sizes
(current size limits are ~10 cm diameter)
Need to understand the atmospheric impact of re-entry
(e.g. Ozone impact, ablation physics)