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For the nth time, it isn't a subjective judgment call about what is or isn't a planet. There's a definition. Look it up, apply it to the situation, and come to a conclusion.

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Get off your dusty old books dating from before relativity explained Mercury's recession, and just put a bit more faith in actually fact checking reliable sources directly yourself?

Also, please get off your high horse. When you come with such an agressive attitude, the impetus is on you to prove your point, instead of just doing nothing more useful than throwing the cheap blow of an Ad Hominem without any extra substance to it than that.

That 18 km/s figure comes from the Lunar and Planetary Institute.

https://www.psi.edu/epo/ktimpact/ktimpact.html says :

Asteroids hit Earth typically at high speeds of 16 to 32 km/sec

Some move way faster and those are the really most dangerous ones. The 18 km/s is just some average, the reality is of course a spectrum.

https://tech.hindustantimes.com/tech/news/asteroid-alert-130-foot-asteroid-hurtling-towards-earth-at-warp-speed-71673588818863.html

That one is said to move "at warp speed" but it is moving at about "only" 6 km/hour. STILL at about twice the size of dimorphos it remains a super dangerous potential extinction event.

Still, the overall logic remains true within an order of magnitude for more or less similarly sized, similar speed asteroids.

Keep on laughing your ass off and judging others while actually contributing absolutely nothing that would be actually useful to the discussion. Congratulations!

No I don't I never said or even implied it, it's you projecting something on me that just ain't there. I think you deeply misread me anbd my intent. Of course such an experiment is a vital one. But all media even NASA website definitely focus only on the half hour differential over the previous 11 hours orbit, and very hard to find data on the actual resulting delta V.

It is cherry picked information to make it seems as if it was a huge effect, but while it is indeed a huge accomplishment, in terms of actual delta V this is a tiny effect.

It is way too easy to just say "Go learn this!" in a condescending and dismissive way. While without correcting anything.

Well, I checked my numbers. Did you? I dare you to do the same computations yourself. And yeah when just trying to get a ball park figure, you are allowed to use simplified formulas, as long as they don't introduce "orders of magnitude" errors. No need to be a "scientist", kinetic energy formulas are simple.

And for tiny angles, sin (angle) is proportional to the angle.

Inverse proportional relationship: Mass <===> Resulting Delta V.

Inverse square proportional relationship: Speed <===> Kinetic energy ==> Resulting angle differential (for small angles) obtained from applying some force.

It's not rocket science. Orbital speed of dimorphos around it's primary is one thing, and it is super slow. Overall speed of a typical asteroid is over ten thousand times higher.

So with DART we got a resulting Delta V of 1 of a centimeter per second.

Over a year, that is approx less than 300 kilometers of deviation. This is only an order of magnitude value here as of couse orbital mechanics mean curved, not straight, trajectories. But the deviation remains a small one. The compounding effects won't magically stack up to somehow give superbly different total values for the final asteroid's position.

But here we want to deflect an asteroid so that it "misses Earth". This means we have to (at most) speed it up or slow it down or deviate it by approx 6500 kilometers (half the Earth's width). So you have to catch the asteroid really early on, or apply way more force than DART did, to succeed. Or preferably, both.

The media is all gloating about the "huge feat" without also talking about how you'd need scores and scores of DARTs to do the ACTUAL job of deviating an actual asteroid successfully, not just apply a super tiny actual delta V to it's orbital period. Something beyond our capabilities. "Just send a more massive DART that moves faster, and/or send a lot of DARTS", that means requiring a LOT more fuel.

We are still far from having a valid asteroid planetary shield defense. Very far. It doesn't take "top scientists" to see that, just checking the numbers at a very basic level and yet at a little bit more depth than just the surface evaluation of "Oh wow half an hour of an 11 orbit that is like about 1/20 of the job done!" when the ACTUAL job isn't changing a slow orbital speed by 1 centimeter per second, but changing a way faster collision vector speed by a whopping lot more.

DART is cool and all, but it fails to properly show how huge the task really is.

Over a small number of launches though. It's commonality with Delta IV Medium gives it some more credit, but generally speaking I'd rather fly on a rocket with 1 failure in 100 than 0 failures in 14, even though 99%<100%.

I used to make the point that Epsilon is also 100% reliable, but that since it only has 5 launches under it's belt that doesn't amount to much in practice.

I was quite vindicated when it recently failed on it's 6th launch, though also a little saddened that I'd no longer be able to use it as an example.

DC-X was a long way short of Falcon 9, or even New Shepard, and the full Delta Clipper would never have been a useful orbital launcher so long as they insisted on it being an SSTO.

SpaceX are still building Falcon boosters at a higher rate than Ariane are building Ariane stacks, despite reuse. Not to mention a lot more upper stages. Consider the following production figures:

Granted, Ariane 5 is heading towards retirement so they're winding production down, but historically it averaged about 6 per year during the 2010s, which is comparable to the rate SpaceX have built Falcon boosters at since reuse started becoming common practice circa 2018, and they show no signs of slowing given they built 7 last year and 3 in just the first two months of this year.

(Note: I'm using maiden launches as a proxy for production figures. Actual completion dates are likely some months earlier, but over a time period of 5+ years it averages out)

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Reuse doesn't necessarily have to reduce the number of rockets you have to build, that's stinkin thinkin.

It can instead allow you to build the same number of rockets but get a lot more launches done with those rockets - as evidenced by the Upper Stage figures for Falcon, which are 1:1 with the number of launches in a given year.

Consider also that SpaceX want to build Starship at a rate of one per month despite it being fully reusable.

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Bruh, go read up on orbital mechanics or something. You really think you know better than the scientists that worked on this mission?

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>Because it makes more money, or rather means Ariane needs less subsidies.

Your entire first argument was that Ariane6 is not an economic choice but a strategic one.

Now you argume that Ariane6 was designed to keep up with the market.

It's about as weird as the people who try to push the narratives that Musk must in no way be given any credit for anything good or impressive that the companies he's been in charge of for 2 decades do

Because we don't have fucking money anymore, France got one of the biggest debt in the world, so yes we are already struggling to fund our public services and army so wasting even more money on space stuff is dumb.

We should just kill the Ariane projects, we will never be on the same level than the USA and Asia in term of space capacities anymore so it's just better to close everything down and put the money somewhere else.

We know how to make planes, so we should just stay at this level rather than wasting billions in space.

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>If that is the case then why even develop Ariane6 as an expressed rival to the Falcon9 of 2017 instead of just subsidising Ariane5 indefinitely?

Because it makes more money, or rather means Ariane needs less subsidies.

And so? We are in 2023, the situation is quite different now.

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