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Comment Re: Note that what's large... (Score 4, Informative) 69

Venus has multiple "tropopauses" and "stratospheres", depending on how you define them. The atmosphere is like a layer cake with multiple convection zones (like Earth's troposphere) separated by areas of dynamic stability (like Earth's stratosphere). And again, ~50-70km is an awfullly long way from the surface, and surface winds are weak. But, there's a lot about Venus that we don't understand.

Comment test run (Score 1) 172

Which manufacturing capacity does ISIS have left? Which engineers have not yet run away from the sinking ship?

Someone is using ISIS as a test run for their latest toy, and it's not the Russians (they would test by themselves). Expect the US or some of its allies to use weaponized small drones in the next war against the next terrorists, the result of "years of military research".

Comment Note that what's large... (Score 3, Informative) 69

.... is the size, not the intensity. The air moves only slightly faster or slower than the surrounding atmosphere as one passes through the wave.

They weren't expected on Venus, though. Venus's surface is dozens of kilometers down, thick and "soupy" there, transitioning to thinner layers above. It was surprising to see that surface features that far away, in a fluid that can compress, would still make clear phenomena like gravity waves in the high atmosphere.

Comment Re:Only a fraction of US munitions... (Score 1, Informative) 172

Our Nobel Peace Prize President dropped 26,000 bombs (real bombs, not little hand grenades)

Probably a lot more than that. You're not understanding the usefulness of air strikes on this sort of combatant.

on various brown people

Right, right. It's because of their skin pigment! For reference, resorting to lazy race baiting doesn't really win arguments (see the most recent election results as an example)

(even though we are not at war).

Yes, I can see you're having some trouble grasping current events. Please don't do anything dangerous to other people in the future. Like, voting.

Comment Re:Top priority? Always? (Score 1) 140

If your companies top priority is to keep data secure, they how/why did you get hacked. They always say that, but clearly that is not the Top Priority

I see you're doing your part by not using dangerous apostrophes where they are needed!

Implicit in any company's statement that security is their top priority is the large bundle of compromises that don't go away whether or not that is your top priority. They could make the data perfectly secure by disconnecting the servers and putting them in a bank vault. They could make sure the data can't be breached by simply destroying all of it. See?

Security can be your Top Priority, but it has to be done in the context of things like still making it available to users across the internet. Doing it while not going bankrupt. Making the service competitively priced so that it can actually be afforded and put to work.

They could have said that the system could only be used on equipment they ship to their clients, connected to the back end through a hardware-based dedicated VPN with biometrics, dongles, and constant nagging by three-factor comms surrounding every time someone hits the enter key ... and of course nobody could or would want to use the system or pay the monthly fee needed to keep something like that alive.

They may very well put security at a higher priority than chipping away at a long list of UX updates, performance under load, documentation, multi-language support, and a thousand other things. Doesn't mean that doing so means they'll be perfect in their security results. Ever run a business like that? No? Give it a whirl. Make security your top priority, and then start paying attention to what that decision means in real life - including in your ability to get and retain customers during that balancing act.

Comment Am I the only one... (Score 5, Interesting) 128

.... who can't help but cheer at my screen when they nail one of those landings? Now I finally understand how sports fans feel when they watch a game and do the same thing ;)

One thing nobody can deny about them is optimism. ;) Seriously, their IPS numbers are, pardon the pun, out of this world. $200k per booster launch. $500k per tanker launch. I mean, really? Good luck with that. No, seriously, good luck with that; I won't be expecting anything close to that, but please by all means prove me wrong ;) ITS would be a great system to have, I've been playing around with some Venus trajectories with it recently. Looks like it can do a low-energy transit with nearly 300 tonnes of payload from LEO and back again with the same, over 400 if starting at a high orbit - but from an economics perspective the high energy transfers actually make more sense.

I noticed a lot of people were confused about why Musk wanted the trips to be so short and was willing to sacrifice so much payload to do so - many assumed it had to do with radiation or something. But the issue is, when your craft costs so much but your launch costs are cheap, you can't have it spending all of its time drifting in deep space, you need to get it back for a new mission as soon as possible. There's a balancing point, in that if you try to go too fast, you reduce useful payload below the point of making up for it with going faster - but a minimum energy trajectory is just not optimal when the ratio between launch costs and transit vehicle cost is so extreme. I come up with the same thing from Venus as they were getting for Mars, although for the Venus case you end up aerobraking to a highly elliptical orbit rather than to the surface for ISRU refill (you need ISRU, but for the ascent stages, so it's not realistic to do so for the return stage in the nearer term). So for Venus they get no refill like on Mars, but they also don't have to do a powered landing nor do an ascent on return - it's six of one, half a dozen of the other. Both are quite accessible with it.

Comment Re:Great strides (Score 1) 128

It depends what you mean by "refurbishing"; each element is different.

The solid rocket boosters, for example, suffered a hard impact into salt water. They then had to be fished out of the water. And of course you don't just "refill" a SRB, they have to be taken apart and recast, then put back together.

The ET is disposable, and had to be rebuilt from scratch.

The orbiter was legitimately reusable, but with design flaws.

I don't blame the shuttle program - they were sort of pigeonholed into this dead end by circumstances. The concept came about during the heyday of the Apollo Programme, when NASA budgets were serious. It was supposed to be a much more reusable, much more maintainable, and somewhat smaller system. It was supposed to then have a huge flight rate supporting all of these big projects that were on NASA's docket, including a permanent moon base and a huge manned orbital station dwarfing ISS, which was supposed to replace Skylab.

But of course, Vietnam and the realities of having soundly trounced the USSR in the space race led to their budgets being slashed, which pushed the program into ever more untenable positions until it was nothing more than a jobs programme. Forget full flyback reusability of all parts. Forget the titanium frame for the shuttle, which would have let it run hot and thus not required so sensitive of a TPS. Go begging for money and be forced to modify the design to meet Air Force requirements, pushing you into an inferior design position. On and on.

If I'd fault them for anything, it'd be for going straight for a full reusable workhorse rather than a small-scale pilot programme first. But those were the days of optimism. Optimism which only recently seems to start being regained.

Either way, the Falcon boosters are a very different beast. A vertical soft landing is hugely different from the SRBs, yet the thermal issues are far easier than with the Shuttle. And the Merlins were designed from the start under the principle of preventing the need for a full teardown. That doesn't mean that they will be cheap to reuse. But it does mean that they have the possibility of it.

I do think SpaceX had a rather clever strategy, in that while their goal was reusable, they made a rocket that in the process was cheap as a disposable. So they could get volume and flight history while working on getting the kinks out. They may have flown too close to the sun with the densified propellants and (externally) unlined COPVs, but obviously, with a company like this, their whole existence is to push the envelope.

Comment Re: Awesome (Score 3, Insightful) 128

Most of Europe agrees with you. And even the US agrees with you up through high school plus with various forms of assistance for college, including state-subsidies, particularly for state colleges, and federal subsidies (direct subsidies, tax credits, and tax breaks), roughly $80B/year each. Pell grants alone cost the government $35B.

Comment Re:Huge numbers! (Score 1) 269

What? Tens of millions of people routinely bitch, in public with their names attached, about every possible person, agency, posture, act, policy and purpose of government across the spectrum from the local PTA to city, county, state, federal, and international governance. There is nothing "brave" about parroting a lazy meme about freeing Snowden from prosecution for some very cut and dry real crimes. Your sense of drama is wildly disconnected from reality. Show me a single person, ever, who has been put into any sort of legal jeopardy for saying out loud, "Snowden should be pardoned." A single example. Specifically.

Comment Re:This will never happen, even if I want it to. (Score 0) 269

I imagine that by this point they have already extracted every bit of intel from him that they can hope to get, which means his greatest value is as a symbol of the double standard of the US government. Keeping him from leaving would just mean losing what little moral high ground they have managed to claim.

Comment Re:No Gut no Glory (Score 1) 67

To be clear:

  * Getting the failure rate down in the lower tenths of a percent or better is what they need to be able to ~10x their launch rate and still be economically viable, since a pad explosion will leave them stuck for just as long and scare off just as high a percentage of their customers whether they're launching 12 a year or 120.
  * SpaceX wants to have reliability like airplanes, and has talked about this frequently.
  * What they want to achieve, and what they need to achieve, are not the same thing. They do not need to achieve airplane-like reliability for the Falcon 9 to be viable.
  * That said, if they ever want to achieve their ultimate IPT plans, they absolutely will need airplane-like reliability. Because they're calling for ~1000 launches per booster on that thing with a turnaround cost of ~200k. They really cannot have anything go wrong with it.

Comment Re:No Gut no Glory (Score 1) 67

It most certainly would be extreme reliability by the standards of the launch industry. The only ones that have better reliability than that that don't have nearly a statistically significant enough number of launches under their belt to assert that. Aka, "they haven't had a failure yet but nowhere near the several hundred launches required to assert a lower fraction of a percent or better failure rate".

We're not talking about airplane reliability here, we're talking about economics (the title of the article is "SpaceX Accident Cost it Hundreds of Millions"). Airplane-like reliability is for the future. We're living in the present.

All COPVs use an inner liner. The problem with SpaceX's COPVs is that they have no outer liner to separate the carbon fibre from the LOX. Outer liners are optional. SpaceX didn't use one. They lost a rocket because of it. They're going to keep trying doing without one. I really hope it doesn't cost them another. CF and LOX aren't fast friends.

Comment Re:Permission? (Score 1) 60

It's hard enough to find affordable LOX dewars. Seems like little ones cost about as much as big SUV-sized tanks. Everyone has LN2 dewars for sale, but you don't put LOX in a LN2 dewar as a general rule unless you're absolutely positive it has no organics (and preferably no silicone) in it, or certain metals. Otherwise it can get a bit... "explodey". The simpler, all-stainless LN2 dewars usually don't have lids, which with LOX would be just plain stupid. You can find used LOX converters online for very cheap, but they generally only will take LOX in, you can only get GOX out.

What I'm saying is if anyone happens to run into an affordable LOX dewar, drop me a line.... ;)

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