It’ll take a bit of thrust to slow these speeders down. “The only good asteroid is the one that falls into the sun.”

Asteroid shock: NASA email reveals agency’s surprise at near-hit – ‘It slipped through’
AN ASTEROID large enough to devastate a city unexpectedly “slipped through” NASA’s defence net, internal space agency emails have revealed.

The asteroid, dubbed 2019 OK, brushed past our planet on July 25 but the rock was not spotted until it closed-in on Earth. NASA later confirmed the asteroid skimmed the planet from a dangerously close distance of just 40,400 miles – one-fifth of the distance to the Moon. A similar surprise in 2013 resulted in a rogue space rock inuring more than 1,000 people with shards from blown-out windows in Russia. Internal NASA emails obtained by BuzzFeed reveal the US space agency was completely caught off-guard by 2019 OK.

Cataloging and continuously updating the inventory is not a problem, even becoming easier day by day. Counting is what computers do best.

I don’t see evacuation as an investment in the future, it’s more like an escape from reality. Spaceflight is what is needed, with footprints on the threats. We need to go to all of them, we need to investigate all of them and we need to work “on” all of them.

Sounds like a new bureau for the Department of Defense, with UN involvement.

The solar system has a long history, and many of the potentially hazardous rocks flying around it have either already collided with some other planet (maybe even us!) or have been ejected out of the system altogether. Others have been kicked into high parabolic orbits that may not bring them back into the inner solar system for centuries. So the system appears to be pretty stable and safe. But every now and then, there is a gravitational encounter that alters an existing orbit, and that alteration may suddenly make it a threat, or direct it into yet another encounter that might make it a threat way down the line.

For example, a comet like Halley’s with a well charted orbit, one that has been observed passing into the inner solar system
numerous times in the past, may be approaching Neptune right now, having its orbit slightly altered so that it will eventually collide with the earth. That collision may not be on its next approach to us, but may be in the distant future, perhaps a dozen passes through our neighborhood later.

We would not see this comet as an immediate threat to us, but careful measurements of its orbital elements might alert us to the fact that its orbit has changed, however slightly, and we need to do a lot of number crunching to determine whether or not it will become a threat in the future. Fortunately, if we know well ahead of time a threat is coming, we have the ability to start working on an appropriate response to it. Knowing we are on a collision course with a nearby object is of little use to us unless it is a small object of limited destructive potential. Our only response would be to hurriedly evacuate those populated areas it was likely to affect.

Truly large objects, capable of planet-wide catastrophic damage, would require long periods of time and large technological investments to implement a defensive strategy (like nudging it into a safer orbit or destroying it). We’re talking planetary mobilization here, like fighting a World War or stopping climate change.

A truly effective planetary defense system would require a detailed inventory of every object orbiting the sun capable of both damaging the earth and potentially being able to hit it. And that catalog would need to be continuously updated. Although this survey would eliminate lots of objects as potential hazards, it would still leave many more that require further monitoring. To use a maritime example, we’re not charting reefs here, we’re tracking icebergs. The two tasks are related, but not identical.

The system described in this NASA proposal might be of use in the event a small collider was the threat, and there is nothing wrong with this, but we should also try to design this first step as one that can be economically scaled up to deal with the real planet busters and dinosaur killers that are lurking out there.

Increased vigilance over the orbiters will inevitably prove a worthy opponent for my planet-killer scenario.

Not tomorrow. Not in the next decade. By the time we get back into that shooting gallery, perhaps.

Also, its a whole different problem keeping an eye on solar system objects, which tend to stay close to the ecliptic and are all traveling in more or less the same direction at predictable speeds, than extrasolar objects which can come from any direction and have a much wider velocity distribution.,

Current theory has it that the Earth is made up of two distinct planets. Billions of years ago, Earth, at the time bit smaller than Mars, was struck by a rogue planet, also a bit smaller than Mars. Earth was liquefied in the impact, but had also suddenly become a lot bigger and the two cores joined. The splash from this event congealed into the Moon.

Rogue planet.

At the moment, the solar system is passing through a very thin vacuum, a sphere of clean space blown empty by a super nova from a few million years ago. It is believed this reprieve from rogue events may continue for the remainder of this century. What makes the rogue so dangerous is that it travels from outside the solar system on a direct trajectory. A sniper shot. There is no parabolic to it.

It’s huge. We see it, then we’re hit.

This is precisely the type of project that should be planned “for eternity”. The initial segments might be useful for limited objectives like evacuating cities before they are hit, but in the long term, we will need years or even decades to implement a full planetary defense. The initial investments should not be a one-shot deal, but the first installments of an ambitious and integrated system planned for the long run. We need to spot these guys many years before they hit us, not just a few months ahead of time.

In addition, such a system could monitor all those bodies that are not currently considered a threat and detect any changes in their orbits (caused by perturbations from other bodies) that might suddenly cause them to become a threat.

I envisage a suite of telescopes and radars coordinated by a permanent institute and dedicated staff, all feeding data to massive computers. Projections of potential encounters could be made decades ahead of time, and there would be plenty of time to be able to devise a planetary defense, whether it would be destroying the object, or perhaps nudging it into a safer orbit. This project would have the facilities to detect and map these bodies, and if necessary, communicate with other observatories to gather more specialized observations. This institute would publish bulletins which could then be scrutinized for potential collisions, and prioritize their risks. It would also act a clearing house for follow up and coordination of other observations collected at other observatories engaged in other types of research.

The solar system is a dynamic place, things are constantly changing and interacting. The good news is that we would have enough warning to do something about it. All the methods currently conceivable of protecting us from collisions are usually much easier if done years ahead of time, instead of rushed at the last minute. This facility could also be designed so that other types of research could be done there which could help defray its cost and extend its usefulness.

I don’t visualize a big telescope or radar, but several of them, with links to other, existing instruments and institutions, permanently funded for the long term. It would operate like NOAA, or the USCGS, or the Weather Service–except in space.