Kosmos 482: questions around a failed 1972 Venera lander still orbiting Earth

Wild coincidence or destiny?

I’m in the space industry. I’ve wanted to visit NZ for ever. Here now, finally. 3 days ago I toured the Ashburton museum and saw this ball.

Now this gets posted on HN which I’ve been ignoring for the last year.

That article mentions them dangling a wrist watch over the space ball to see if it was radioactive. How would this work?

NZ is home to other mysterious balls:

https://en.wikipedia.org/wiki/Moeraki_Boulders

Think of a very very elliptical orbit, one that's nearly a line and consider what happens when you take a bit of energy off the orbiting object. At perigee, when the energy is almost entirely kinetic, you're mostly just changing the velocity, rather than altitude of the object. At apogee, when the energy is almost entirely potential, it's the other way round - the change is almost entirely one of altitude. This is further stretched by the much more 'visible' effect of potential energy changes on altitude than of kinetic energy changes on velocity.

the atmospheric drag at perigee happens perpendicular to the object speed, which is tangential to the gravity field, so the object doesn't get shifts on it's vertical speed, only it's energy, having less to convert in potential energy (i.e. apogee height)

in the thereabout of perigee you have two arms, one inbound and one outbound. the horizontal component of the drag for both is all in the direction against the travel and slow the craft without changing the vertical component of its speed

the vertical component of the drag (for as long as the craft has the energy to get's outside of the dense atmosphere) kind of cancels out, as the drag force inbound pushes against your down velocity vector and the drag force outbound pushes against your up velocity vector.

there is however a small energy loss due to the fact that the journey trough the atmosphere isn't perfectly simmetrical, since you're losing speed along all the way, the inbound leg is shorter than the outbound leg, causing the vertical component of the drag going outside to slightly exceed the component of the vertical drag coming in - so your perigee does change little by litte due this (and other more nuanced effects, but we're painting with a large brush here) - this asymmetry gets stronger the more you stay in the atmosphere and the furthest you dip in the dense area, until you ultimately don't have the energy to escape anymore.

the fact that the atmosphere isn't on/off like that but has a long boundary layer stretching far from the dense parts kinda complicates things a little more, because drag is applied the whole circle, but not by that much.

The rule of thumb you can use to make this intuitive:

A change in velocity at a certain point x on an orbit will change the entire orbit, except that orbit will still continue to go through that one point x.

So slowing down at perigee will not alter the perigee. (It is actually the most delta-v efficient way to lower the apogee.)

That is about it.

Kosmos 954 crashed in northern Canada with parts of the nuclear reactor still intact. The Soviets did eventually pay part of the bill Canada issued for the clean-up operation. It's the only claim so far made under the Space Liability Convention. [1] And yes, I believe the Russian Federation did inherit liability for orbiting Soviet space junk.

https://en.wikipedia.org/wiki/Space_Liability_Convention

https://en.wikipedia.org/wiki/Outer_Space_Treaty says they inherited the USSR’s entry into the “Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies”, which, among others, states states shall be liable for damage caused by their space objects, so they should fess up.

Depending on where it falls, in today’s political climate, they might say it’s part of a special military operation against nazis, though.

It seems unlikely that terminal velocity of a bullet would be terribly dangerous.

The lander mass is around 1000 lb, so picture the results of dropping a grand piano off a skyscraper.

Depending on how it's modeled, 2024 to 2027 (with earlier being higher likelihood), or 2023 to 2025. No way to predict location but it'll be somewhere between 52°N and 52°S.

I doubt that it's predictable that far out. Perhaps a particular band of land, but not some specific area.

The distribution of people is not uniform over the potential impact area, which is, as you mention yourself, not the whole surface of the earth. The error bars on this are too huge even by napkin standards, for this to work as an estimate.

That's an English billion (10^12), given that there are a million square metres to the square km?

Mind you, I wouldn't want to be standing within 18m of where it lands, so either definition of "billion" does make sense.

That's assuming it comes straight down. Given that most people are somewhere around one to two metres tall, if it came in at a shallow angle it could ruin hundreds of people's day.

Orbital inclination is 52°. That leaves about 400 million km^2.

You’re off by a few orders of magnitude.

Would we be able to shoot it down before it hits anything?

The movie came out 15 years later and I doubt anyone remembered or knew about titanium balls falling on New Zealand. Spaceballs was always meant to be a direct parody of Star Wars.

I remember from that time people were more freaked out about Skylab falling down to earth--there were novelty t-shirts with a big target and "Skylab target" printed on them, all the late night TV hosts joked about it, etc. Skylab falling back to earth was a big event: https://www.youtube.com/watch?v=zoVXuKQ__0s

Pretty sure it’s just because the word balls is funny.

52 degrees pretty well lines up with Russia's southern border. Virtually no overlap.