NASA satellite, Russian spacecraft crossed within 65 ft (20 m) of each other

Their movements are also very smooth and predictable. Probably more a "what if there's a slight disturbance" thing, or "this is within our measurement / prediction error range and they could collide"

Two problems are orbit determination accuracy (bottlenecked by the amount of ground stations and the low quality of public NORAD data) and prediction of perturbations (dominated by the atmosphere and space weather at low orbits). Both areas progressed greatly in the last decade, but still not enough.

Cars can maneuver much more readily, travel at much lower velocities, have road traction so aren't affected by their gravitational attraction to each other, and don't have a third axis of separation (altitude) to deal with, including changes in that axis due to micro-gravity and atmospheric fluctuations.

This makes long-term modelling of orbits/intersections very difficult, and the error bounds are much too large to give any reliable projections on the order of 5 metres. We would know that they came within 5 metres of each other when they come within 5 metres of each other; not long before.

also, in this case (as with all 'debris'), one of the vehicles is dead, so you can't do active ranging on it, just passive radar. Much less accurate. Active rangefinding is good to ~ meter accuracy at geosynch, passive radar is nowhere near that close. The two factors for how good your orbit fit are how good your range data is, and how frequently you get samples. To get accurate orbits, you need to look often, and there are lots of objects up there - way more than there are antennas on the ground keeping track of them.

Space weather and positional measurement accuracy limits how precisely you can predict your orbit, especially over longer time periods. Maneuvers use precious fuel. Not all objects can make maneuvers (debris). If there are two active sats, they have to coordinate as to not make it worse.

One of the challenges might also be distinguishing between debris and a concealed spy satellite.

Though it seems many actors are reluctant on implementing something to capture space debris as this could open the doors for capturing more then just debris (as in foreign spy satellites and the like).

That requires imaginative ideas for paying for such missions.

How about a nice directed energy tool to zap it out of orbit?

You could simply vaporise the smaller bits.

Not a nitpick and yes should be :-) I can't edit but Dang is always around...

At those kinds of speeds, the orbital paths have to be really improbably similar to not have "bullet" like destructive effects. The relative velocity will almost aways be in the same order of magnitude as the ground speed and definitely more than bullet speed which is super slow compared to the ground speed.

And calculating the collision speed is pretty complex while the ground speed is static so I can imagine the press just take that.

After all pretty much any speed will be destructive to a satellite that's not designed to be bumped around.

> It always irks me that discussion of space debris invariably talks about their high velocity relative to the ground, which is completely meaningless.

It's obviously an issue with point of view, but considering only relative velocity isn't also a solution.

If two spacecrafts are on a close approach trajectory, one of them might need to course correct to fix that. Changing the relative direction might allow them to avoid the collision, but will also change their orbit, leading to other problems down the road (e.g., out of wack apo/periapsis). Fixing the orbit after the close approach will also cost more fuel and/or angular momentum, which is in short supply on most spacecrafts.

I like to think about it like two nascar cars. Sure, if you are driving one, the other cars seem to be almost not moving from your seat, but the spectators see something completely different. Any small change (from the driver's view) in steering can have big effects overall.

> but it's misleading to label them as travelling at "17,500 mph (28,160 kph)"

Really is? Ground speed is still what I expect and want to read, relative speed to each other at time of rendezvous would also be nice sure.. still, I mean depending on vectors, it may be over- or underestimating almost the same.. and I claim ground speed is what most people would expect. As someone said, the chance that their rendezvous speed is magnitudes off is slim.

Orbital mechanics are difficult to understand unless you're a Ksp pro or some NASA dude that has played Ksp as a pro. The concept of "falling" while traveling at 28k kph is difficult for the public to understand as there is no frame of reference in everyday life. But everyone can understand that 28k kph is "really really fast!".

It is writing for the lowest common denominator which outside of scientific articles, is probably for the best. Imagine if every article had to re-state some even minor point about orbital mechanics. You'd lose too many people in the weeds.

tl;dr: People are ignorant/stupid/dumb/don't care. The author needs to write for that audience.

Eh, with these particular orbits (~600km, 74.1 and 82.5 deg) it's somewhat fair - high inclination LEO is always crowded and risky. With sun-synchronous orbits it's often even worse than "17,500mph" because the hit can come from almost any direction.

Compare this with the GEO, where everything is in one slow plane, the orbit is well-kept and dead stuff drifts away.

The vast majority of encounters are thousands of meters per second relative velocity. There is enough energy in this to smash a satellite pretty good, even if it encounters one of the thousands of pieces of relatively small debris.

If two objects have a close approach once today, this means they will likely have another in the future due to the nature of orbits.

The visualizations are done this way because there is no way to draw everything to scale and have them be visible.

Planes move slower and still have midair commissions.

Maybe the amount of press it gets is too high for you, but it is a real concern for satellite operators. The amount of media attention given to celebrities is the real problem.

That's still progress. My now automatic reaction in US reporting is "how much is that in football fields? Or perhaps libraries of congress?" /s?