Research into deflecting potentially world-destroying asteroids is apparently not a 'national priority' for the UK The European Space Agency (ESA) has let people know where €129.4m of work for its Hera mission will go. The UK is, unsurprisingly, not on the list. Hera, named for the Greek goddess of marriage, will follow NASA's Double Asteroid Redirect Test (DART) spacecraft to a rendezvous with the Didymos pair of Near-Earth asteroids. …
People, it's a good thing the Brits aren't interested.
Looking at the British Government's performance on Covid and Brexit etc, I would be deeply concerned if they had responsibility for anything at all in a project to defend the Earth from an asteroid impact.
You'd only want to give them stuff that you wanted royally arsed up. Although I suspect they would even manage to arse that up.
Here are some numbers.
Falcon Heavy - 63,000kg to LEO @ $150m
1 launch per month for 10 year = 7500 tonnes at $18bn (ish, bulk saving not applied)
With a 7500 tonne mass limit I think we could come up with a solution for deflecting quite a large asteroid.
Some asteroids are well-known, mapped and tracked. We could conceivably flag them as dangerous several orbits in advance of a possible collision. Years, decades even. Throw enough money at the problem, and we could probably manage to stick a multi-ton ion engine on it, and have it run continuously for, say, ten years. I can think of a few futuristic-but-not-implausible-for-the-near-future tech advances that could improve on this further.
My guts tell me that this should be enough to nudge a dangerous asteroid out of the way, provided that it's well-known and not too large, but in all honesty I can't be bothered to run the math now... sorry about that.
It will _never_ be possible. Just do the numbers . . . .
People who have done the numbers have concluded that collisions can be averted given sufficient warning, although it is more doubtful if the asteroid is ~10km or larger. The strategy is to deflect it to both miss the planet by a few Earth radii and to not enter a gravitational resonance region that means it will collide on a later pass (called a "keyhole").
One way is to speed it up on its descent towards perihelion - speeding up is less energetic than slowing it down. Ten years out, a velocity change of about 3.5 mm/s is needed.
Nuclear fireball icon, because that's one of the proposed ways of generating a lot of impulse for an achievable launch weight.
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"speeding up is less energetic than slowing it down"Well, this is obviously false. A 2kg object going at 1m/s has 1J of kinetic energy. To slow it by 1m/s requires removing 1J. To speed it up by 1m/s requires 3J, because the same object at 2m/s has 4J of kinetic energy.
My "speed it up on its descent towards perihelion" was the explanation. An object travelling in an elliptic orbit speeds up as it falls towards perihelion and slows down as it rises to aphelion. It is travelling at its fastest at perihelion and then starts slowing down as it starts to rise again. In classical mechanics, it is trading potential energy for kinetic energy as it falls, and kinetic energy for potential energy as it rises in the orbit.
Hence, if you displace an object in its orbit towards its perihelion then it will increase in speed because some of its gravitational potential energy is converted to kinetic energy, irrespective of any additional energy you have given it. Consequently for an object travelling in an elliptic orbit, it takes less energy to speed it up than to slow it down.
The effect of the impulse you provide will be both to displace the object, which will have that effect, and to add (in this case) energy from the orbit and so modify its path slightly.
Sunlight could be our friend here:
https://solarsystem.nasa.gov/resources/703/how-sunlight-pushes-asteroids/
If (admittedly a big if) we can find it early enough we could put reflective sheets on one side of the rotating body to alter the orbit using sunlight, which would then heat different ties of the asteroid differently. Of course we'd nee a great deal of reflective material and some way of tethering it to the surface.
OR we could use the reflective material to reflect the sun's rays onto one side of the asteroid, so it gets hotter, which might also work. we cannot 'stop' an asteroid, but, as has been stated, changing its orbit by a small amount might be enough to save life on Earth.
It will _never_ be possible. Just do the numbers
I did the numbers. If we can intercept an object 0.5AU away (which is certainly plausible) we need to deflect it by 0.002 degrees to change it from Earth-impacting to Earth-skimming. This is slightly simplified: the proper calculation might end up worse, say by an order of magnitude (it will be less), so say 0.02 degrees.
Yes, we can stop asteroids hitting Earth: we may not be able to stop donosaur-killer sized ones, we can certainly stop merely civilization-ending ones. We can very definitely stop country-killers.
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A UK Space Agency spokesperson said: "The UK made a record investment in European Space Agency programmes in November 2019, including £80m on space safety and security for missions on space weather and space debris. Our investment decisions are driven by our national priorities and commitment to delivering value for money."
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Just like the US Customs wanker grabbing earbuds the other day here: the second sentence could just as well be left off completely.
Even the prior sentence is full of smug boast. Is there some universal directive for American and British politicians and functionaries to always interpose self-congratulation and self-satisfaction into the simplest of announcements ?
Seriously.
S'like how now one is demanded to use self-laudatory phrasing discussing oneself on CVs etc., whereas in a more normal state people who spoke well of themselves were shunned. This is getting a serious problem and makes one feel one's living in the Soviet State.
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EDIT: add ref for the US Wanker:
https://www.theregister.com/2020/09/14/us_customs_earpods/
For those wondering, here is the ESA Funding Pie Chart.
The ESA is a strictly what-you-put-in-you-get-out organisation. There's no "winning" or "losing". If you put €100M in, they'll spend €100M in your country. Base membership contributions are based on GDP and then there are optional programmes that states can additionally sign up to (like Hera). Spend for optional projects only goes back to participating nations.
The UK currently contributes (and receives) ~9% of the "ESA budget from Member States" (including Switzerland & Canada).
France and Germany contribute 26.9% and 20.1% respectively.
So you would expect France and Germany to get twice as much spend as the UK (because they put twice as much in), even before they start soaking up money from the EU projects.
The EU then puts in about €1.53B for EU projects like Galileo and Copernicus. Spending for those projects has to go back to EU states, or participating non-EU states who have signed up to those projects (like Switzerland).
When the author states:
Bremen-based OHB took a substantial bite out of ESA's Copernicus award pie earlier this year while the UK, a major ESA contributor, did not fare so well
This is a bit misleading. Copernicus is an EU project delivered by ESA - not an "ESA project". Once we left the EU, we lost our entitlement to a slice of that €1.53Bn they drop in for Galileo/Copernicus/etc. We didn't "not fare well". It wasn't an open contest that we lost. We surrendered our entitlement by leaving the EU. If we were still in, a chunk of Copernicus would have had to come to us.
We didn't "not fare well". It wasn't an open contest that we lost. We surrendered our entitlement by leaving the EU.
Or as you say, it's just the way these 'workshare' deals go.. Although possibly pre-empting our departure from the EUroclub. So Germany contributes the most funding, Germany gets the most work. And then given the number of contributors, work is shared amongst the remainder leading to design by committee. Or just bloated committees.
So it might be better for the UK and the UK's space sector to look at international project proposals and partner with Japan, India etc instead. Or even the US, where universities do some interesting projects. There'll still be aspects of pork barrel politics, but maybe less than within the ESA.
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those animals with no "known" technological advancement.
All the smart ones built a giant flying saucer and took every bit of evidence with them. They pop back from time ton time.
The remaining ones had a huge international dance party using their telepathic powers to chat each other up while off their tits on mushrooms.
It's true unless you can prove it otherwise.
It is gravity and our lack of technology that stops us getting out.
A long long time ago, someone got drunk and mis-behaved with a time machine, and was marooned on Earth with the instruction to evolve into a more responsible life form.
Judging by the current state of the world, we have yet to complete our sentence. :o(
Is an underground hardened bunker that would (likely) survive an extinction level event.
Provided it doesn't get smacked point blank a la "Money Supermarket" as this would be most unfortunate.
Rumor has it that its in Cumbria but this is based on out of date information circa 1998.
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