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Comment by sandworm101 | Hacker News Reader

And where is the evidence that this is actually debris, space junk, and not rock or other "natural" material? NASA projects this idea that space is clean, that the only stuff in orbit is what we put there. That is simply incorrect. Literal tons of material falls onto earth from space each day. Virtually none of it is tracked. Calling any impact the result of "debris" requires some evidence or logic to explain the source.

edit: 2019 paper listing over 1400 detected impact sites on ISS. https://www.hou.usra.edu/meetings/orbitaldebris2019/orbital2...

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I don't think the term "space debris" is only applied to man-made space debris. Yes, there are rocks and other stuff out there, and those are just as dangerous as the man-made debris. AFAIK both types fall under the term space debris.

Of course, the fact that there's more and more space debris is quite clearly linked to everything we launch.

Really? I havent seen that math. For that to be true, the number of collisions would have to be rising faster than the rate at which we put stuff up there. Natural sources would cause a steady increase (more stuff launched, more exposed to natural impacts) whereas not-natural junk impacts should increase at a rate higher than exposure (compound increased exposure with increased risk from more objects). All i have seen are studies saying that the number of impacts is increasing, not that they are accellerating faster than launch rates.

No math is involved, only common sense : there's a certain amount of natural space debris surrounding planet earth. This amount has reached a steady state over the past few millions or billions of years. Over the past few decades we've started launching stuff into orbit. Some of that stuff explodes. Hence, there is now more debris surrounding planet earth.

Whether or not the amount of extra space debris has already caused an increase in collisions is a different matter, for which some statistics would be required. But that wasn't the point I was making.

In fact, it's quite the opposite of the point I was making : something has hit the ISS, and whether it's man-made or natural is (AFAIK) not specified at this time.

Something hits the ISS almost every day. This collision gets noticed because the hole it left is larger than average, but if you look close enough the ISS is covered in tiny impact damages.

This paper (2019) lists over 1400 impact sites on the ISS, and that is only the ones that have been discovered. https://www.hou.usra.edu/meetings/orbitaldebris2019/orbital2...

> there's a certain amount of natural space debris surrounding planet earth. This amount has reached a steady state over the past few millions or billions of years.

For what it is worth, I would question this assumption. Why would the amount of natural space debris around earth be at a steady state? Meteor showers [1] are one example of how the amount of space debris is not at a steady state.

[1] Meteor Showers: https://en.wikipedia.org/wiki/Meteor_shower

See Kessler syndrome (https://en.wikipedia.org/wiki/Kessler_syndrome).

This is somewhat correct. "Space debris" does include both human and natural debris. Since most natural debris orbits the sun and most human debris orbits the earth, Nasa uses the term "orbital debris" to refer to human caused debris.[0]

The difference in location means that while more natural debris enters earth's atmosphere, that doesn't mean that chances of colliding with natural debris is commensurately high. Orbital debris spends much more time near earth before it burns up, so has much higher collision chances per object that burns up.

In fact, the chance of collision with natural debris vs orbital debris will be very dependent on the specific orbit you are discussing as orbital debris is not evenly distributed.[1]

I higly doubt that there isn't a significant range of orbits where the risk of damage from orbital debris exceeds the risk from natural debris.

Edit: added citations

[0] https://www.nasa.gov/mission_pages/station/news/orbital_debr...

[1] https://www.nasa.gov/news/debris_faq.html

The technical term is "micrometeoroids and orbital debris" (MMOD). (https://www.nasa.gov/centers/wstf/site_tour/remote_hypervelo...)

Does it matter? If you're upset about the specific language used in the article, I'm sure there's ways of letting them know that doesn't involve a comment section of reasonably intelligent people.

Yes because this is part of a narrative re space debris. Lots of people are looking into debris/junk removal. Those projects are being given serious funding. If the impact risk from natural objects far outweighs the risk from space junk, those projects are pointless. We should then focus on hardening spacecraft against inevitable collision rather than attempting to remove existing debris. The debate is relevant to which risk mitigation strategy is most effective.

Most orbital junk flies between 7-800km above Earth and the vast majority is lower than 2,000km.

The orbital graveyard is 35,000km. Assuming you are right and our biggest concern is regular space rocks, then why are these areas of especially high concern?

If you saying that the distribution of space rocks should be constantly high like what we see in our rings of trash. But it's not. Earth practically has rings that we can detect. Where did all that material come from? Why is the density of space trash detectably higher the closer to earth you get?

Before you say gravity, remember that these things are in stable orbit. Wandering space rocks have a very low chance of achieving that without intervention.

Distribution may be homogenous but velocity is not. The natural rocks near earth are much faster and therefore more dangerous. They are falling towards earth, picking up velocity as they dip into our gravity well.

Distribution of space debris is not homogeneous at all.

The natural background of rocks/dust should be evenly distributed, with exceptions for things like comet tails.

> should be evenly distributed

This is definitely not true. I don't know why you would expect a 3+ body gravity system would result in an even distribution of natural debris.

It depends on scale. Certainly there are areas of our solar system with greater or lesser densities, but those differences are vast. There should be no appreciable difference in density across a few hundred kilometers.

That is very different from your intial statement, doesn't backup your original point, and is only true if you include an additional list of exceptions (such as plantary rings and lagrange points).

I simply don't see any facts to backup your thesis that natural debris are a greater risk than orbital debris to spacecraft in earth orbit (esp the lower orbits).

35 years ago we used to draw solutions in school about how to clean up space junk. They had us convinced space would be unusable in a few years if nothing was done.

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