Planetary Defense and Offense

Last week, NASA launched the first spacecraft intended to deflect an asteroid.  The asteroid in question is 6 million miles away, but the goal of the Double Asteroid Redirection Test (DART) mission is to push the asteroid and see what happens to its trajectory.  The goal is not so much to focus on the small number of large asteroids that could wipe out much of life on the planet, which are well catalogued and characterised, but rather the next tier of asteroids that would ‘only’ wipe out a city, but which are much less well catalogued.

Asteroids are not the only danger.  Space junk had already been a problem and has grown to the point that serious concerns have even been raised that there could be a reinforcing feedback process leading to a ‘runaway cascade of fragments’ which would make near-earth space unusable. Add to these concerns intervention in space that does not always have such benign motives. The previous week, Russia had riled up the wider space community by using an anti-satellite weapon (granted, on its own old satellite) that created an enormous amount of debris (see some visualisations of its impact).  The debris created problems for many national and private actors including SpaceX’s Starlink internet system and even posed a danger to the astronauts (from the US, Germany and Russia) on the International Space Station not just at the time but have posed a continued danger to spacewalks even weeks later.  These types of anti-satellite tests (which have been conducted by all major powers) even led the US Pentagon to propose a moratorium on further anti-satellite tests.  Ironically, in 2008, Russia and China proposed an international treaty banning anti-satellite weapons coincident with the US launching the first major anti-satellite weapon.

We have discussed some challenging topics that arguably need to be addressed here on Earth — Should it be easier or harder to regulate space?

Even from these three examples (space junk, anti-satellite weapons, planetary defenses) we can see that different solutions might follow.  Picking one or more of these examples, which is the best approach to addressing these challenges? How important is international cooperation and how effective is it likely to be? What role is there for private actors?