Lukaszenko

Is there any difference between pumping "uphill" and pumping to the bottom, but against the pressure of the "hill"?

I also played an earlier version in Ironman mode, and I concur that it gives you more enjoyment from the game. Makes you be VERY careful about how (or if) you aerobrake and how much extra fuel you bring, makes you more meticulous when it comes to testing, especially manned, and gives you reason to build in escape systems....all just like in real space programs. Lately though there was too much dancing around with all the shifting variables in the game, so I reverted to quicksave/ load mode. Even in Ironman though I recommend saving often, in the very likely case that you lose the mission because of a bug.

It's also empty, with all the heavy bits at the bottom. The middle just has to support its own weight. I doubt that it can do this trick fully loaded.

Same here. I know exactly how you feel. Except I actually thought I was exactly on time. Planned my whole day around it I know there'll be more, but this was the first of its kind. It's just not the same...

I just came in to watch the 11:00 launch....and I see this booster on the ship already? Howtf did I miss this piece of history

Isn't this the first time the Dragon is flying since then?

The trick is that you DON'T start at an Earth-like orbit around the Sun. You start in LEO. If you then just barely escape the Earth, and then make another burn to go to Mars (as opposed to burning directly to a Mars transfer from LEO) the difference will be much larger. As others have said, it takes a lot of energy to climb out of the Earth's gravity well, and it takes a lot of energy to go to Mars. Due to Oberth, you can almost buy one and get one free. If you go even further, the discounts really start to stack up.

Acceleration denotes how fast velocity is changing. It doesn’t actually say how MUCH it changes, which is exactly what delta V specifies, while conversely not actually caring about how fast it does it. So no, they are not the same thing. Equating delta V to acceleration would be akin to equating distance to velocity. Yeah you need one to do the other, but they are different concepts. You don’t have to drive 100 miles, for example, in order to drive 100 mph.

As others have mentioned, don't forget that the sun also orbits the earth. Once you understand that, the rest of your question is also answered.

I'm ok with letting it burn up. That's how space works. I mean, it would definitely be cool to keep it around as a showpiece, but if every space mission designer had to contend with "maybe we can bring it back to put in a museum?", or some variation thereof, that would be a hell of a hurdle to jump over. I mean where do we draw the line? Should we bring back the Apollo hardware? The Mars rovers? The Voyagers? If you can do it cheaply and easily, fine, but don't spend other space missions' budgets just so we can sit back and fan our vanity.

Project HARP fired 180 kg to an altitude of 180 km...so apparently the whole atmospheric drag/ heating thing can be worked around, at least to a degree.

Successful or not, the reason they are done is because until that point nobody knows for sure, no matter how much money was spent on simulations. And that's what I was responding to, the claim that a prototype isn't built until 100% confident. And also to the claim that aerospace companies don't blow stuff up. They do. There is NEVER 100% confident, even after simulations AND tests. They do software, they do wind tunnels, they do stress, they do certification, they do actual missions, they do actual missions with people...and yet excrements still breaks and things explode and people die. Likewise, if a broken wing can be called a successful test, then so can a broken rocket and a hole in a barge, depending what exactly SpaceX was trying to get out of it. I'd also venture to say that the total cost of this particular test was orders of magnitude less than an engine blade-out test.

Right. My point was that not everything can be simulated in a computer. Even something as simple and well understood as a ring around a fan blade. Or even a cantilevered beam:

I'm no SpaceX, but is a hole in a barge really worth worrying about if it gives you critical test data from a 10s of millions of dollars orbital rocket booster? There's only so much a simulator does and can show you. And yes, even Airbus and Boeing DO blow stuff up to see if it works. Only difference here is that SpaceX was going to lose the extremely expensive piece of equipment anyway.

It gets exponentially more effective the faster you go.

They were applauding in the hosted webcast right after the video cut off...

Perhaps SES is irritated that SpaceX is constantly delaying launches, or perhaps they are happy that their cargo is being handled with such extreme care. I suspect, particularly in the world of rocket launches, that it’s the latter. What’s a couple days, especially when their launch has already been delayed by months, and yet SpaceX is forgoing reusability to make up for it. I know it’s not a good comparison, but this forum has been waiting patiently for what seems like close to a year of delayed launches (1.1) as well, and the general consensus seems to be “take your time, to make it right”.

Supposedly this will get fixed in 1.1. If it ever comes

What's up with this 1:4x? Edit: Wait...did I just rewatch the old launch? Ha...I thought they aborted the launch AGAIN at the exact same time

October Sky?

Ferrfluid seals are pretty cool. I've seen demonstrations of them at work. Basically a magnetic oily substance that's held in place with magnets. Doesn't wear because it's oil, doesn't leak because it's liquid and hence no gaps, doesn't have friction because it's oil. Problem solved. https://www.youtube.com/watch?v=jQj0C44H3ys

As everyone is saying, if you throw a rock faster straight up, it goes higher up. At the top, it's velocity is the lowest (zero, in fact, if you throw it straight up). Ok, so a satellite goes faster sideways, not up. Imagine a swing then. In order to higher, you push yourself harder at the bottom, sideways. The swing rope then curves your sideways path and converts it into height. So sideways speed and height are interconnected, and affect each other. In the case of a satellite, gravity acts like the swing rope to curve your path. It's still not a perfect analogy because the path of a swing is usually fixed, so the faster you go the harder the rope pulls on you to curve your path. Gravity doesn't fix the path, but the force is fixed. The point is that sideways and up/ down are still interconnected. I recommend playing around with some gravity simulators online, such as: http://waowen.screaming.net/revision/force&motion/ncananim.htm

AND on top of everything, what do you get back with the 2nd stage? 1 engine, as opposed to the first stage's 9 engines.

....or players who would rather focus on design. I don't consider SpaceX, ULA, or whoever else to be "cheating".

I don't know. But I'm saying that, judging from the landing video, this was not a (or the) problem.