I understand this is a bit of a selfish request and entirely a matter of personal preference given my job, but I do wish you guys would talk a little bit more about up and coming companies in the Space industry so I'd know who to keep my eyes on. Not sure if the rest of readership would care but thought I'd throw the idea out there on the off chance others would also be interested.

I don't see any other newsletters / research articles out there that are anywhere near as knowledgeable and I expect more and more people to turn their attention to startups in this space (no pun intended..)

Anyway, thanks again for the incredibly high quality content!

Seems like a bigger threat to astronomy is clouds.

For the operational phase SpaceX added a sunshade which reflects light away from the Earth. This plus the higher orbit makes the satellites dim enough that they cannot be seen with the naked eye. This sunshade was designed with feedback from astronomers at the often mentioned LSST, which is the single telescope most affected by large satellite constellations. It will prevent artifacts from the imaging sensor's pixels becoming saturated, which is the main concern. The satellites will be visible to the telescope but can be filtered out with standard techniques already in use to filter out the thousands of other satellites already in orbit. See https://www.spacex.com/updates/starlink-update-04-28-2020/

See here: https://www.spacex.com/updates/starlink-update-04-28-2020/

What actually happens if they spot an asteroid with collision potential? Is there anything we can do about it?

If it's years or decades away, we could try.

(I know, it's not exactly that simple. But still.... ;) )

I would assume the "working out the international politics" part includes "a multinational effort among nuclear-armed countries that spot-checks the kill vehicles can actually do the thing claimed to do."

... but in terms of whether stopping is possible, I believe that depends on the amount of kinetic energy you can apply to it. I'd have to sit down and do some real math to determine the practical stopping power of a kill fleet, but to give a thumbnail comparison: each Starlink sat is about 500 lbs, which is about the weight of one B57 nuclear bomb, with a yield of 5-20kt. There are about 660 Starlinks in orbit now... A constellation of kill vehicles of the same size could have the ability to deliver an upper-bound of 13.2 megatons of explosive energy. According to one source (https://www.space.com/39971-asteroid-destruction-nuclear-bom...), 3 megatons should be sufficient (though the parameters for individual delivery of smaller payloads vs. one big nuke would of course be different).

This is, of course, all a terrible idea; nobody's gonna be comfortable with a mega-constellation of nukes in orbit.

> The scientists found that a 500-joule-per-gram laser blast was required to break apart a model space rock 0.3 inches to 0.4 inches in diameter (8 to 10 millimeters), if that blast were directed at a premade cavity in the "asteroid." Without the cavity, the necessary energy was about 650 joules per gram.