DerekL1963

If this were true - then why does your first graph show a steady descent?

Not quite true. Solids can last a long time, but not indefinitely.

You can also use a Sandbox save and the Hyperedit mod and practice on Laythe itself. That's how I do all of my engineering development.

Yeah, so you did. I misread, mea culpa.

Relative to this case? Keeping their mouths shut and not releasing information related to the investigation.

Actually, the worst pre-Challenger failure occurred at temperatures well within the specified operating range. The cold contributed to the accident, but it did not cause the accident. That's why, in addition to joint heaters they added stiffening pins to the redesigned joint, because the basic problem was the joint opening up when the case pressurized at ignition.

The body of rotation form wasn't introduced for quieting. It was introduced for better underwater performance and to allow a single screw. The latter was particularly important for nuclear boats as the amount of power you can put into the screw without cavitation is more-or-less proportional to the area of the blades. Twin screw boats were limited in the size of the screw, and that sharply limited performance. In fact, the body of rotation hull introduced a new form of noise - blade rate, which arose from the interaction between the wake of the sail and the rotating propeller.

0.o It doesn't take any serious engineering and analysis chops to realize that throwing an uncontrolled Orbiter into the airstream at T+70 wouldn't be significantly different than doing so at T+73. (The Challenger wasn't destroyed due to explosive forces, as there was no explosion. It was ripped apart by aerodynamic forces when it ended up broadside to the airflow.) That's why NASA abandoned thrust termination in the first place - there was no practical way to provide a system that could maintain attitude control and thrust the Orbiter away from the stack. Let's just say that you should review the Wikipedia article on the Challenger accident and leave it at that.

Utter nonsense. There wouldn't have been thrust termination in the first place unless the Orbiter could power itself away from the stack and maintain control. Nope. There are no benign abort modes prior to SRB burnout. None, zero, zip, nada.

Avgas and commercial grade kerosene are mass produced in a competitive market. RP-1 is neither. It's a specialized product produced in (relatively) small quantities. NASA didn't seem to have a problem doing so. Thrust termination (for the Shuttle) was dropped because a propulsion system powerful enough to get the orbiter away from the stack was too heavy, not because of plume impingement.

Elon loves playing to the crowds. He's also obsessed with control his image and the spin. People with serious work to do, and used to cooperation from the manufacturers, are not at all amused by this behavior.

I should have realized years ago that it's much easier to build large space station mockups in the SPH rather than VAB.

No, I have not been avoiding your point, I have addressed it repeatedly. All you have done is insist that I have missed your point without once addressing the points I have raised. Precisely. And the same is true of every other form of transport that might be used to carry CT's exemplar.

I have never said otherwise. What I have pointed out is that niches (such as the CT machines CatastrophicFailure keeps harping on) don't drive industries and that they're a poor match for scheduled hub-to-hub transport. Hub-to-hub makes it's money by minimizing per-unit costs, by flying with seats and holds filled as near to capacity as possible on every flight.

No, I'm trying to explain to you how the shipping industry works - it's built on large volume and standardized handling, because that's where the money is. Not in edge cases. For BFR to be economical and competitive, it has to go where the volume and revenue is. Yep. That's the other stumbling block and the other reason that drives the industry to standardization and volume - driving down the other costs makes the premium more palatable.

That was supposed to say "gasoline"... meaning handling small quantities of familiar liquids isn't really relevant to handling industrial scale quantities. Shouldn't have been writing one reply while thinking about another. Yup. Had a friend in high school end up in the emergency room because trusted in the old saw that "diesel was relatively safe and hard to ignite". (Thankfully his eye healed.) I'd been using diesel to burn garbage on the farm, knew better, and backed way the hell away. I don't care what it is, if it's volatile and flammable I'm going to treat it with respect and caution. And folks handling it industrial quantities will too.

I never said there wasn't. What I was point out that you're missing the forest for the trees - your wife's particular situation is an edge case. Edge cases don't drive business cases. And irregular shipments of unusual size and weight aren't going to drive SpaceX's notional cargo business. What will drive that business is the same thing that drives every other cargo service - large volumes of cargo in standardized containers with minimal labor costs. Volumes sufficient to fill the hold every day, every flight. Or, to put it another way, there's a reason why your wife has to rent an entire truck for one cargo rather than simply putting it on a scheduled run. And it's not the size and weight - trucks routinely haul shipping containers and breakbulk loads far larger and far heavier.

0.o Kerosene is a highly volatile material than can be set off by a tiny spark. Worse yet, it's liquid and flows and can vaporize - and both can lead to ignition far from the actual storage location. Solids on the other hand, stay put and can't be ignited by a spark that isn't in contact with them. Kerosene seems safe and familiar because we fill our cars with it on daily basis, but handling it in industrial quantities can be quite a headache. (Ditto LOX, which is produced at a seperate plant and trucked to the launch site.) Setting aside that none of your post actually addressed costs... They don't have to be cheap - they only have to cheaper than the alternatives. That's why the Shuttle (which focused on up front costs and largely ignored operating costs) went with SRB's. That's why solids are popular for adding a little extra oomph off the pad or as the final stage.

That's your wife as an originator of a shipment, we're talking about SpaceX as the transport mode. I cannot emphasize this enough - the two are not the same thing. SpaceX's notional cargo business is going to be built around high volume hub-to-hub, with standardized containers and simplified straightforward handling - because that's where the money is. Filling the cargo hold day after day, every day, every flight. Because you can charge a premium for them, there's money to had in outsize and unusual services... but that's gravy rather than bread and butter.

And also can't take significant G forces I bet. And probably is shipped broken down into components anyhow as it has to fit through standard doors and down standard hallways and fit the load limits of standard elevators. And almost certainly very rarely has to be shipped now to some arbitrary distant destination. Here in 2018, no mode of transport makes its money on cargo of irregular sizes and wildly varying demand (either in time and in geography). Standardized sizes (of containers if nothing else), predictable demand, and steady schedules rule the roost - anything more is going to cost the big bucks.

It's a nailbiting ride to orbit (and must be done manually, MJ can't handle it), but orbit it does. Some fine tuning needed, but the basic concept works. As always, more info in the Airship Adventures thread (link in my .sig) for those interested.

It's a massive pain and a nail-biting ride to orbit... But orbit it does. Which means I've now tested (individually) each phase of the mission - launch, trans-Duna injection and cruise, Duna capture, and reentry and recovery to hullborn flight. Touching down on Duna... Not going so well. (Though I know what I did wrong there...) So, now for an integrated end-to-end test. Once that's successful, really the only thing standing in my way is Squad fixing the bugged landing gear so I can recover my crew. Some notes on performance: With 160 units of nuclear fuel onboard, she has approx 200 (Kerbin) days of flight endurance... I'll be bored of flying around Duna long before the powerplant dies. This is a SCANSat map of Duna, with terrain over 6km (for a safety factor) in white. With a service ceiling of 7-8km, over 90% of the planet's surface is accessible.

Superior by what measure? That's a serious question - because solid upper stages wouldn't be so common if they didn't offer advantages over liquids. Most noticeably, they're far simpler and hence more reliable.

No, it doesn't. Thrust takes time to decay. Completely false. You can blow the bottom off or blow open exhaust ports without destroying the entire stage. So, essentially, your entire position is based on two entirely mistaken beliefs. Yep. Every LES I've ever seen discussed is based around three standards: First, sufficient thrust to pull away from the booster even at maximum acceleration. Second, the capability to pitch over and pull clear of said booster even if it continues to thrust. Third the ability to clear the fireball and debris fields resulting from flight termination. You seriously think they don't carefully simulate launch escape situation for liquid boosters to ensure they meet the standards outlined above?

Canopus is correct, you cut the engines and fire the LES at practically the same time. (This is why LES have such murderously high t/w ratios and produce high G forces on the occupants.) Clearance is then a product of lower (and eventually zero) acceleration of the booster due to loss of thrust and acceleration (of the capsule) by the LES. As far as your statement goes, you're not thinking through the process - if you have adequate clearance, then by definition it's safe to fire the destruct system regardless of whether the booster is solid or liquid.