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Comment "At an airport" meaning Class B airspace. (Score 4, Informative) 44

The subheading in the linked article ("It's the first waiver granted for flight in Class B airspace since the FAA came up with commercial drone rules.") makes sense, but the summary, title, and article are a bit wonky.

It's been perfectly legal for a certified commercial Remote Pilot to fly at an airport since Part 103 went into effect, but only in Class G airspace. Small airports with Class E Surface or Class D airspace would require a waiver, and waivers have been had for those for a while now. Larger airports with Class C airspace took longer before the FAA began processing (and approving) waivers, but there had not been any waivers of Class B airspace. This is the first.

Of course, you can only get a waiver under Part 103, so if you're a hobby pilot, the five-mile rule is in effect. For Part 103 Remote Pilots, on the other hand, it's all about airspace. (Most of the FAA Knowledge Exam is airspace and weather.)

Comment Re:All Electric? Cool! (Score 5, Informative) 130

Also, chemical propellant is "heavy", meaning it takes much more mass to get an equivalent kick. If you want real words, the Isp (specific impulse) is lower for chemical propellant engines than for ion engines. With all electric satellites, you can carry much less propellant, meaning you can have a satellite of comparable capability in much less mass. In the case of these two satellites, the Boeing BSS-702SP platform they're built on means you can fit two on a "normal" GTO launch. That basically halves your launch costs.

The tradeoffs are that while all electric propulsion is very "fuel efficient", the thrust of ion engines is a very small fraction of that of the more conventional chemical propellant engines, so instead of taking days to settle in to your final orbit, it can take weeks of slow orbit raising. This is a "cost" that may or may not be worth the trade. Also, since the 702SP satellites are launched in pairs, a launch failure could take out two birds with one... rocket. To give a bit of insurance against this, Eutelsat and ABS chose to split two rockets. They'd each fly one satellite per launch, meaning they only risked one of their two each flight in case of a Very Bad Day.

Comment Don't forget IBM PCjr! (Score 1) 183

I never had one, but a friend whose dad worked for IBM did, complete with a whole stack of sidecar expansions. It actually looked rather entertaining as wide as it ended up.

Admittedly, they stacked to the side and were only for expansion, but they did stack (or daisy chain, if you use more mellifluous terminology).

Comment Re:NoScript (Score 2) 307

QuickJava lets you add a simple button to enable/disable javascript (and Java, Flash, Silverlight, and more). It doesn't let you whitelist, as it's a set of simple toggles, but it's quite convenient.

I turned most of its buttons off, but the javascript one comes in quite handy, and I can keep flash completely disabled except in the rare cases I want it for something.

Comment Re:No KSP at SpaceX? (Score 1) 213

The SRBs from Shuttle launches were indeed reused... after a fashion. Each booster was four segments. After each flight and recovery, the boosters were disassembled and the segments renovated and reloaded. The segments were not kept together as a set, so each SRB used in a launch would have four segments each with their own history. (This was expressly noted on NASA TV during each launch, with comments about the oldest and newest segments on the flight and so on.)

As for SpaceX, early Falcon 9 flights had parachutes on the first stage, but the stages did not survive reentry (much less make it all the way to landing). Since you can not land anything large on Mars with parachutes, SpaceX would have eventually had to work on hypersonic retropropulsion, propulsive landings, and so on; they merely pivoted away from the parachute "dead end" and went straight to propulsive recovery with Falcon 9 v1.1.

Comment Re:Shooting themselves in the foot (Score 1) 229

"Our stores will transition to being galleries, where you can see the car and ask questions of our staff, but we will not be able to discuss price or complete a sale in the store. However, that can still be done at our Manhattan store just over the river in Chelsea or our King of Prussia store near Philadelphia."

Sales over the border? Already ready. Collecting tax revenue? If NJ is anything like my state, they'll collect that when you register the vehicle in NJ. The state isn't going to be out much money, but the dealers are protected by the politicians who get their campaign contributions, and neither has to give a hoot about inconveniencing the people. (The people inconvenienced weren't going to buy from the dealers, so no money lost there, and they aren't numerous enough to make a dent in the elections, so that's all fine and dandy, too.)

Comment Re:Won't they hit the ISS on a future orbit? (Score 5, Informative) 52

They're launched from the nadir side in a nadir-aft 45-degree direction to prevent collision with the ISS. That imparts a small negative delta-V (with insertion velocity between 1.1 and 1.7 m/s), so their orbit would begin just slightly below the ISS. Additionally, one of the requirements for CubeSats launched from J-SSOD is that they have a ballistic coefficient of 120 kg/m^2 or less. This means that their orbits will decay faster than the ISS orbit, precluding any potential for collisions over time.

(The life expectancy on orbit of a CubeSat launched from J-SSOD is something like 100-150 days, depending on orbital parameters as of deployment, solar activity, etc.)

Comment The first stage is suborbital. (Score 5, Interesting) 127

Heat shields are the efficient way to slow from orbital speeds for reentry (e.g. the Shuttle), but conveniently for recovery the first stage isn't orbital. Grasshopper is basically a modified Falcon 9 first stage, and the goal of the testing is recovery of the first stage of Falcon 9-R, which is much easier than reentry from orbit..

We're not talking single stage to orbit here, and recovery of the second stage would certainly involve a heat shield. The first stage is a different animal. SpaceX seems to be intending to use a boost-back trajectory concept. I look forward to seeing how that works. (The controlled water "landing" attempt will be something to see, too, of course.)

Comment Leatherman killed the tool market. (Score 5, Funny) 333

Leatherman killed the tool market when it came out. Why buy a single-purpose tool when you can get many more features for a little bit more money?

Sometimes having something that *doesn't* slice, dice, and julienne fries is the better choice. I mean, sure, I could do many small repairs using just a leatherman, but a nice set of wrenches and drivers makes working on my bike *much* nicer. Or how about crescent wrenches (or shifting spanners, as the case may be)? You can handle all variety of nuts, bolts, and fittings. SAE, metric, square, hex? All are open to you. Yet anyone who spends much time working on mechanical things knows that a crescent wrench, while convenient, is often vastly inferior to a good set of wrenches.

When I'm out on a ride, I carry a small multitool that *does* do a bunch of things in one small, inexpensive, unobtrusive package, just as when I'm out and about, I can get some reading done on my Nexus 7. The Nexus 7 is convenient, but if I ever broke my e-ink Kindle, I'd have a replacement ordered that very day. E-ink readers are basically designed to fill the niche of "electronic trade paperback for avid readers". They fill that niche exceedingly well, and avid readers are a renewable resource.

Comment Awkward... (Score 5, Interesting) 599

Actually, I was thinking more along the lines of the Hogfather (specifically from the movie).

While I enjoyed this first Hobbit movie, I found the Radagast scenes awkward (like an old family photo with too-large glasses and sisters with poofy bangs). Radagast and his bunny sled seemed too much like something right out of Discworld, which would be delightful except that combining Discworld and Middle Earth yields a very large impedance mismatch.

Comment Intentionally once for me. (Score 4, Interesting) 566

I can't speak for his experience, but I can tell my own story about being intentionally run down by a motor vehicle.

It was a dark and stormless night (hehe). To be specific, it was late on the Wednesday night before Thanksgiving, and I was riding across town to drop some goodies off at a friend's place. We have virtually no bike paths, and those we have tend not to be connected to anything, so it's all road riding here. The road was one of those five-lane jobs (two in each direction and a suicide left in the middle), and traffic was extremely sparse. (We're talking maybe half a dozen cars total at the busiest intersection along the route.)

When that light with maybe half a dozen vehicles turned green, I rode on and was passed by the cars that had been waiting. Not far down the road one of them, a pickup truck, moved into the suicide left lane as if he was going to turn into some apartments, but he didn't immediately complete the turn in spite of no oncoming traffic. As I approached (two lanes away, riding near the white stripe on the outside edge of the outside lane), all of the sudden I saw his white reverse lights come on. He floored it and cranked the wheel around, backing hard across both lanes in my direction and continuing all the way into a doctor's office parking lot.

Had I been expecting it, I could likely have quick-turned a bit harder to avoid the hit, but you don't expect someone to try to injure or kill you. So, my turn wasn't quite hard enough, and I went into the side of the pickup as my bike went down. The guy continued back, crushing my front wheel, then paused for a moment before peeling out and driving off. My reaction wasn't quick enough to avoid the assault, but it was just fast enough to let me escape with a broken bike and only minor injuries (scrapes and bruises, mainly).

So, a pickup truck stops in the middle of the road for no reason, waits for the bike, throws it into reverse, and floors it across both lanes and into a parking lot. Can't get much more blatant than that. Moments after the guy drove off, a car pulled into the parking lot to check how badly I was injured. He had seen the whole thing and was virtually dumbfounded. He had never seen something like that in his life, he said, although I'd hope most people would fall into that category. I got a very close and intimate look at the pickup truck (obviously). I had a witness who saw the whole thing. So, why didn't anything come of it? The guy had an illegally obscured license plate. Without being able to ID the vehicle, the police would be happy to take a statement from me, but that was the extent of it.

The vast majority of car/bike incidents I've had are simply oblivious drivers, e.g. passing too closely or returning to your lane before the back of their vehicle has passed you. Even antagonistic drivers are often so due to ignorance, e.g. "Get on the sidewalk!" (which is not only dangerous but also expressly against the law here). Still, every so often you get a psychopath. What can you do (other than mounting a few Go Pro cameras around your bike to gather and preserve evidence)?

Comment Re:A tsunami in deep water is a non-event. (Score 1) 332

You are correct. A ship can take much larger waves directly into the bow than it can take abeam. It's perfectly logical if you think about it. The bow is designed to plow into the water, so it'll deflect the wave energy better, and designers know storms will come, so they design to some extent or another for waves breaking over the bow. Waves running directly into the side have a large surface to work on.

Additionally, consider the simple geometry. A ship is going to be much more stable in the pitch axis (where it is a nice, long lever) than in the roll axis (where it's much closer to a round log). Tipping a ship end-over-end would require something more like a Michael Bay movie, while capsizing it by rolling it over requires much less force.

The images I've seen of this ship show something much more like a floating rig platform than a plain old large yacht. It has a long axis, but it's much wider than a "normal" ship. That being the case, it would have more stability in the long axis, but it should be stable enough in the short axis. You *could* just go ahead and build a platform instead of a ship, with deep ballasts well below wave action attached by legs to the main platform well above the waves, but that expense, inconvenience of access, and greatly reduced mobility is apparently undesirable.

Comment A tsunami in deep water is a non-event. (Score 2) 332

Off-shore in deep water, there is absolutely no danger whatsoever from a tsunami. A tsunami is only a problem as it reaches shore, as it's there that the very long period waves just keep coming and coming and piling up water. In deep water, there's just a very, very long swell of minuscule amplitude.

Storm waves are vastly more significant. Their period is short enough and their amplitude great enough to potentially cause significant damage to oceangoing vessels. Considering also the occasional rogue wave (a wave or short set of waves at several times the amplitude of the prevailing wave conditions at the time), and having lifeboat/evacuation drills every so often would be best practice. At least the area in question is outside the hurricane belt, so hurricane evacuations (such as those from Gulf of Mexico oil rigs) shouldn't be required.

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