I thought I also read something about kerosene leaving some sort of residue in the plumbing, turbopumps, etc. For a disposable it just doesn't matter, but for a reusable it means extra maintenance. The other thing was Zubrin suggesting that methane/oxygen was relatively easy to generate on Mars, for a return flight. Since Musk probably isn't planning on returning, that would be for a Mars space program.
Since you sound familiar with this stuff, I'm wondering about Falcon Heavy. I've seen that it's moving to methane/oxygen propellents. My understanding has been that kerosene/oxygen were generally best for a first stage, and hydrogen/oxygen is best for an upper stage where specific impulse is more important than tank size.
With methan/oxygen it seems obvious that they'd like to run the engine on mars-native fuel. But I also get the impression that kerosene/oxygen might not be the best thing for reusability because it gums up the works, and methane/oxygen would be better.
So I see three factor here - Earth launch, reuse, and Mars launch. Do you have any feel for this tradeoff set?
Your statement should apply equally to pedestrians and cyclists. However, pedestrians aren't the ones arguing that they'd be safer walking down the middle of the road than on the sidewalk.
Neither cyclists nor pedestrians travel down the middle of the road.
Because most pedestrians that are hit by an automobile are not on the sidewalk, they're in the road.
As I said, only a small fraction of cyclists are hit while traveling down the road not near an intersection.
At an intersection, by definition, YOU'RE IN THE ROAD, whether you had been on a sidewalk or not. Now read that last sentence again, because you seem to be incapable of understanding that simple geometric fact.
The issue is that motorists rarely look for objects moving faster than 0.5mph coming from a sidewalk. Maybe instead of making cyclists stop and dismount at every goddamned driveway as you want, we should address the original source of the risk and institute a nationwide comprehensive 15 mph speed limit.
I never suggested they didn't get killed by cars all the time. I said they manage to handle intersections just fine. That is, with an acceptable surivaval rate.
Where did you come up with that idea? Pedestrians are routinely killed at intersections, coming from sidewalks. Where do you get the idea that that's acceptable?
I don't hear nearly as much whining from pedestrians rights groups as I do from cyclists rights groups, so I assume that pedestrians have greater success in intersections than cyclists do. Of course, it's possible that cyclists are more whiney. Could go either way.
Maybe they're whiny because they hear unsubstantiated crap like this all the time from ill-informed people like you.
I must have skimmed TFA too fast. So this appears to be for the capsule, not the launcher? I thought there was a launcher competition going too, and that was going to be bigger than Atlas 5 or Delta IV.
Somehow pedestrians manage to handle intersections just fine, all while staying on sidewalks and crosswalks. Perhaps if navigating intersections is too challenging on a bicycle, one might dismount and walk the bike cross?
Pedestrians get killed by cars all the time. Please stop talking out of your ass.
"Safe" and "Exciting" have a different meaning in this context. Realize that Falcon 9 has already flown several times, and though plagued with the delays that plague pretty much all launches, has a good track record which will presumably continue through its use in a manned launch. The "Exciting" choice sounds about as "Safe" as it gets in rocketry, to me.
The Boeing design is new, though presumably using tried and true components from a tried and true design. There will no doubt be unmanned test launches, but the first men on top will still be sitting on a rocket with far less launch history than the Falcon 9. The "Safe" choice sounds just a bit more "Exciting" this way.
Disclaimer - TFA doesn't say if this is for Falcon 9 or Falcon Heavy. Falcon Heavy is all-new, with only the company track record behind it. That puts SpaceX and Boeing on a more even footing, with Boeing having a longer track record and SpaceX having done more launches recently.
OTOH, I seriously doubt that the head of Boeing plans on going through a Boeing launch personally. The head of SpaceX does.
Seriously... If we really want to foster a private space industry, both companies need to be kept moving forward. At this stage of the game, the contract needs to be split in order to improve the viability of both efforts. Cutthroat cost competition can happen later.
Yet only something like 5% of bike injuries involve being rear-ended by cars on roads.
Almost all other cases would involve intersections of some sort, where being on the sidewalk doesn't help or is counterproductive. You're still vulnerable to the high-speed cars while crossing roads, and you're more likely to collide because they're not looking at where you're coming from.
Of course, but that's "sunk cost" in a manner of speaking, available under no better terms to SpaceX than to any other US-based company.
However given that basis, typical contract projects are then paid for by the government, on top of "historical knowledge." SpaceX used the historical knowledge, as others do, but then paid for their additional development themselves.
They no longer provide MBTF metrics for consumer (Deskstar) class drives but the uncorrectable error rate on Ultrastars is an order of magnitude higher than the others, which is a common distinction between consumer and enterprise-grade drives.
If we could only arrange for every segment of every bike trip to enjoy a 3% downhill grade, a stiff tail wind, 40 degF dewpoint and partly cloudy skies, then almost nobody would even bother to buy a car.
You are not kept away from cars on a sidewalk.
Since drivers rarely look for traffic on sidewalks as they go in and out of driveways and side streets, you run a high risk of getting run over at every curb cut. At least when you're on the road, drivers usually see you when they bother to glance up from their cellphones.
SpaceX did the development themselves, from what I understand. They're now doing fixed-cost government contracts, unlike the rest of the space industry in the U.S.
My beef is with the way it seems that most US companies are there to make money, and see their products as a way to do so. I'd rather see them be there to build their products, and see money as a way to keep making those products.
For the car analogy, assuming support for both ways would properly continue, would you rather by a car built by a car geek, or buy a car built by a money geek?
Wow, this is really fascinating!
One set of systemd advocates suggests that the Unix Way is obsolete, holding Linux back, and is overdue to be discarded.
Now another systemd advocate suggests that systemd is fulfilling the Unix Way better than SysV Init.
I will say now, as I said months ago, that systemd would be much less controversial if it had been packaged differently. I'm not the only one making that statement, and yet for all of its claimed modularity at compile time, systemd is still one package.
"Here's something to think about: How come you never see a headline like `Psychic Wins Lottery.'" -- Comedian Jay Leno
