Seventy-Six Seconds

Forty thousand objects we can track

Surveillance networks follow about 40,000 objects in orbit. Only around 11,000 of them are working satellites; the rest are dead spacecraft, spent rocket stages and fragments.

The dangerous part is the part we can’t see

For every object big enough to track, ESA’s models estimate dozens more large enough to disable a satellite, and thousands of paint-fleck-sized bullets.

Segment widths are schematic (ordered, not to scale). Counts for untracked sizes are ESA MASTER model estimates, not direct observations.

Dodging, doubling

Starlink’s avoidance manoeuvres per six-month reporting period have risen roughly eightfold in three years as the fleet, and everything around it, has grown.

Each point = six-month period ending on the date shown. SpaceX manoeuvres when collision odds exceed ~3 in 10 million, far stricter than the common 1-in-10,000 industry threshold, so counts reflect caution as well as crowding.

How junk makes more junk

A single collision or weapons test can add thousands of trackable fragments at once — the chain reaction known as Kessler syndrome.

Tracked fragments (≳10 cm) catalogued after each event. Each also produced far more untracked pieces — an estimated 150,000+ from Fengyun-1C alone.

Altitude decides the sentence

Thin air slowly drags debris down. Low junk falls within a year or so; junk a few hundred kilometres higher can outlast every civilisation so far.

Approximate, illustrative lifetimes: real values swing widely with solar activity and an object’s mass-to-area ratio (e.g. 3 months to 8+ years at 400 km).

What a near-miss costs

Orbital speeds turn a bolt into a bomb, and even the crewed station has to get out of the way.

Why it matters, and what helps

The dodging works, until it doesn’t. Every swerve is a collision that didn’t happen. But fragments don’t steer, and ESA warns that debris would keep growing even if launches stopped tomorrow.