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by jsprogrammer 3865 days ago
That still has nothing to do with orbit, making Elon's tweet(s) a non-sequitor.

Edit: I see the Musk posse has arrived at this comment.

2 comments

When stories with titles like "Your Move, SpaceX: Blue Origin Just Secretly Landed a Reusable Rocket"[0], "Blue Origin Beats SpaceX In Landing Reusable Rocket"[1], "Move over SpaceX! Jeff Bezos' Blue Origin successfully lands a reusable rocket in Texas beating Elon Musk's firm to it"[2], are the main articles about it for me on google news, I can understand how he might feel the need to make the point to the general public that they've not achieved the feat SpaceX is attempting.

[0] - http://motherboard.vice.com/en_uk/read/your-move-spacex-blue... [1] - http://www.popsci.com/blue-origin-beats-spacex-in-landing-re... [2] - http://www.dailymail.co.uk/sciencetech/article-3331885/Move-...

The TV News re-served the 'first time ever' speech tonight. I sighed.
Through all the ads on those sites, I still saw nothing about orbit.

The reusable part of a Falcon (assuming it actually lands undamaged)[0] doesn't go into orbit either.

Edit: Stay classy HN.

[0] "I don't expect the Falcon 9 to have a reusable upper stage" http://shitelonsays.com/transcript/elon-musk-at-mits-aeroast...

You're missing the point. The media is basically doing an apples/apples comparison with BO and SpaceX. The tweet was necessary to point out that they're not competing in the same space.
You are focusing on the word 'orbit' and not the overall meaning. The forest for the trees. You are being downvoted for arguing about something completely pointless.
If my comments are pointless arguing, so are Elon's.

Worse, Elon's are just factually incorrect (e.g. "The energy needed is the square, i.e. 9 units for space and 900 for orbit.") [and, yet, it remains, uncontested, at the top of this thread].

>It is, however, important to clear up the difference between "space" and "orbit", as described well by https://what-if.xkcd.com/58/

is a non-sequitor because no one seems to have confused space and orbit. Additionally, the comparable part of SpaceX's machines (the first stage of the Falcon 9) doesn't go into orbit (it is supposed to land not far from the launch site and does not loop around the Earth to do it).

What is the import of "orbit"? Elon is the one that brought the word into the conversation, not me.

>You are focusing on the word 'orbit' and not the overall meaning.

Then, please, what is the overall meaning of those tweets?

Everyone else has already told you, but I'll tell you again. The media is saying Elon was just beat at his own game. Elon tweeted to point out that it's a horrible comparison, what he's been trying to do is much harder.

End of story. If you can't see that, I don't care any more. I was just trying to help.

>The media is saying Elon was just beat at his own game.

The media is not a single, conscious entity. Some Gizmodo blog may have claimed as such, but I think you'll have a very hard time producing any other person who would claim that what a Gizmodo blog says is what the entire media is saying.

>Elon tweeted to point out that it's a horrible comparison

Not really. There are comparables: stick goes up, stick goes down without crashing.

Elon only appears to have made a non-sequitor argument (unless someone shows where the media made the claim that space and orbit were the same thing).

Ultimately, this is probably a defect of Twitter's character limit. It is extremely difficult to put a fully reasoned argument into a single tweet.

Regarding the factually incorrect bit, could you elaborate? I was under the impression that the energy required was proportional to the square of the velocity, so a 10x increase in velocity (from ~Mach 3 to ~Mach 30) would result in a 100x increase in energy required, which seems to be what he's saying.

Is my understanding inaccurate?

Energy is proportional to the square of the velocity, but the fuel required to reach a given delta-V scales exponentially.
Well, if you take the sentence:

>The energy needed is the square, i.e. 9 units for space and 900 for orbit.

at face value. It is either claiming that 9^2 = 900 or, it either mistated the units for space or mistated the units for orbit. This is incorrect.

If you take into account the context of the prior sentence:

>Getting to space needs ~Mach 3, but GTO orbit requires ~Mach 30.

you can probably work out 3^2 = 9 and 30^2 = 900. However, as InclinedPlane said, that's only in an idealized number, in reality, you must expend even more energy than that to achieve Mach 30 from the surface of the Earth.

We can check back to the prior contexts:

>Congrats to Jeff Bezos and the BO team for achieving VTOL on their booster

>It is, however, important to clear up the difference between "space" and "orbit", as described well by https://what-if.xkcd.com/58/

To be short: you'd need to find where Jeff Bezos or the BO team claimed anything about "orbit".

Since others have already given up on this conversation, I probably will too.

Here's the thing. SpaceX already landed a rocket. Lots of people have landed lots of things. So saying Blue Origin beat SpaceX to something, you have to be more specific about what that something was. SpaceX isn't even trying to land a tiny test rocket (which they already have), they're trying to land real full size rockets on real launches that go to orbit. It's a huge difference.

In other words, nobody said "orbit". But they did say Blue Origin beat SpaceX, which doesn't make any sense.

>Here's the thing. SpaceX already landed a rocket.

Right, which is why this entire thread is so confusing.

>In other words, nobody said "orbit".

Exactly. This makes the tweet a non-sequitor.

>But they did say Blue Origin beat SpaceX, which doesn't make any sense.

Yes, anyone who said that is incorrect. However, Elon did not directly address those people (at least not in these tweets).