DerekL1963

The rocket is two switches on the steering wheel - one to bring it to "idle" power, and a second to bring it to "full" power. (Plus assorted toggles on the control panel.) Since it use H2O2 as oxidiser, presumably the "idle" mode is to warm the cat pack and ignite the solid propellant before going full throttle. My guess is that this eases startup transients.

From the Launch Vehicle Options section of the Mission Design appendix: (Links added by me to link directly to the relevant performance data - especially as the FH's has changed over time.) "It should be noted that the Falcon Heavy could also be considered in this timeframe, however data available to the team at the time of mission analysis indicated its performance for the missions considered would be in the same range as the Delta IV Heavy".

Yes. The current contract is for a study, but they appear to be serious for the long term.

Essentially zero. Not impossible, but improbable as all [curse word].

Yeah, what DDE said. Your proposal isn't science, or even science fiction - it's fantasy. If you've started a model before running the numbers, you're far down the wrong path.

Again, Tater is spot on. SpaceX is planning on rapid turnaround (minimal maintenance), not high cadence.

Atlas-D used ground controlled radio guidance, subsequent versions used fully self contained inertial guidance systems. Neither Titan -I or -II used a star tracker. The first operational US strategic ballistic missile to use a star tracker was Trident-I. (Poseidon was slated to be upgraded to stellar-inertial guidance, but the program was cancelled by President Nixon (IIRC) because the increased accuracy was considered 'too provocative to the Soviets'.) While time varied between launching system, prep time (that time between receipt of the launch order and missile away) never appears to have exceeded an hour. (Down to 15 minutes in the later versions.) In the parlance of US strategic weapons 'Alert' means "ready to accept the launch order", not "ready to launch". While Atlas (and Titan-I) had a limited ability to hold between being prepared to launch and actually launching, that capability does not appear to have ever been used operationally. The concept was to proceed to directly to launch on receipt of the launch command.

A polar orbit (as specified in the article and the requirements) is very useful for various kinds of surveillance birds. Fast turnaround allowing the launch of many payloads (as specified in the article and the requirements) is very useful in the event of hostile action against orbital assets.

NO US ICBM (or IRBM, or SLBM) has ever flown 'that way' (simply point in the right direction and burn till fuel exhaustion). All of them have either used some form of thrust termination or flew a shaped trajectory that brings the point of exhaustion and the desired velocity to equality. (Trident -I and -II use a method known as "Generalized Energy Management Steering" to accomplish the latter.) Atlas flew on the sustainer until it was just short of the desired velocity, and the sustainer was shut down. (The high t/w ratio and the uncertainty of thrust decay of the big engines made it impossible to shut them down precisely on time with proper velocity with the technology of the day.) Those two itty-bitty LR-101 verniers (1000lb thrust) then propelled the vehicle to the desired final velocity, then they shut down and the warhead separated. All available information indicates that powered flight [for ICBM's] is over long before apoapsis. (Which makes sense - the earlier a velocity increment is applied to a RV, the bigger the difference at the end of the trajectory.)

Tired from setting up all day for an event this weekend, but Tater has it spot on. You have to balance the costs (mostly potential performance losses) against the benefits. People are pointing towards TMA-22's launch conditions, but don't mention schedule pressure... it had already been delayed two months, meaning TMA-02M was that much closer to it's "expiration date" (Soyuz only has a limited lifespan on-orbit). The delay of -22 also meant crew rotation was delayed. The Soviets and Russians have launched in some awful weather, but from the available evidence they don't make a habit of it.

Yup... And there are all but endless references in the model railroading community to scratchbuilding structures in H0 scale. Also, for furniture and details, check out the dollhouse community.

How does it balance on the provided stands? They strike me as kinda rickety for something so large and heavy.

This design has been around since at least the 1960's.

Honestly, if you're adding complexity (and cost!) to solve basic design problems (launch TWR)... That's pretty much a sign that you should ball up that design, throw it in the nearest receptacle, and start over fresh.

It's a winged rocket that flies a powered ballistic trajectory and subsequently lands via aerodynamics, it's not a winged air breather than flies an aerodynamic trajectory. Therefore it 'solves' most of the problems of air launches by not being an air launch in the first place. (Or, to put it another way - the problems of air launch comes from being limited to wingborne air breathing altitudes and speeds.) It also gives away the two advantages that air launch does have... First by requiring a dedicated vertical launch facility. Second by carrying a portion of the fuel in the wingborne portion of the platform, and not requiring oxidizer for the wingborne phase of the flight. (It's not even wingborne during that phase.) That being said... A 3,000 pound payload to polar orbit on a rocket "the size of a bizjet"? Seriously doubtful even without the dead weight of the wings.

If your flight rate is slower than your turnover rate - every flight is a first flight whether the booster is expendable or reusable.

Paper rockets are always cheaper than real rockets.

I said nothing of the sort, so don't put words in my mouth. All I did was point out that direct comparisons on the basis of cost (to quote you: "cost is everything"), is a deeply flawed approach. Not to mention, there's not many cases where a combination of 2-3 vehicles can accomplish a Shuttle mission. In part due to Soyuz's low passenger capacity (1, unless the Soyuz crew also undergoes cross training, which the Shuttle's crew didn't) and due to the weight penalties imposed by the need to supply those extra services for the payload that Shuttle does and expendables don't. Again, I'm not defending the Shuttle (it only sounds like it because I'm not hating on it or repeating the redonkulous notions that many space fans have), merely pointing out reality. Which is about the most irrelevant comparison ever - not only because raw volume is completely useless, but you've failed to account for the number of launches needed to launch all the stuff to fill that volume and make it useful. (Empty volume isn't of much use - whether it's your house or ISS, it's the stuff that makes it useful.) For reference, ISS weighs about five and half times what Skylab did, and you're not going to get that weight in three launches. You're right back to dozens of launches (just for the stuff). (And yes, Soyuz (or crewed Dragon) v. Shuttle is subcompact v. full size pickup truck - the cargo vehicles are light pickups at best.) I never said otherwise, I only pointed things that's are as true as the Law of Gravity. If you increase the number of launches, you increase the risk the program is exposed to. If you take the Shuttle out of the equation, then a lot of things get a lot more complicated. All of this is real world engineering, and it's not the one dimensional (usually cost) problem that folks keep trying to shoehorn it into.

Not really, no. Cost is only everything in the insanely disconnected from reality world that most space fans seem to inhabit. In the real world capability matters as much if not more than cost. Space fans blithely, routinely, and repeatedly root for a subcompact because it's cheaper than a full size pickup* - but out in the real world nobody sober and sane would confuse the two, let alone suggest that the former could do the latter's job. *And completely fail to consider the cost of replacing the capabilities... And there's a lot of capabilities to the Shuttle they never think of, like the ability to rendezvous, to support spacewalks, to provide power, attitude control, and other services that aren't going to be cheap to develop a replacement for. All of which will be thrown away at the end of the mission if the payload is launched on an expendable... And which also means you can't perform a straight $/kg comparison between Shuttle and (say) Proton because you have to account for those costs.

There's more to it than just ore%... The number and size of drills and the size of converter you have installed matters too. (And there can be 'holes' of low concentration even in high average concentration areas.) Pics of your craft will help us troubleshoot.

The current version (Soyuz MS) has only flown four missions... Well, two complete missions and two currently underway. You're probably thinking of Soyuz TMA-M, which flew twenty missions successfully (if you disregard the rumors from reliable sources about at least one hard landing and possibly one instance of the propulsion module failing to separate properly). But my basic point still stands, the safety and reliability record of Soyuz doesn't hold up that well once you stop with the emotional "safer than any other vehicle" and start looking at the numbers and actual events. And lurking behind many "safe" landings are numerous accidents that didn't cause any deaths... Soyuz is known to have started re-entry at least three times with the propulsion module still attached. Then there's the time they jettisoned the service module (containing all but a few hours of their life support) - and then their retrorockets failed. Soyuz TMA was infamous for having the guidance computer fail leading to a high-G ballistic re-entry. (Yeah, the backup system saved them - but if the primary keeps failing, you have a problem.) Then there's a number of loss-of-mission incidents where the crew returned to Earth early because they were unable to dock... Plus the two aborts. Soyuz's reputation rests mainly on being Not The Shuttle and on Shuttle detractors refusing to hold it to the same standards. (Making the overly generous presumption that they're even aware of it's history and flaws.) <Sorry for the late reply, I've been busy the past week.>

You're welcome, thanks for reading!

The one whose reliability is almost statistically almost indistinguishable from the Space Shuttle? The same one that aborted multiple flights because it couldn't dock? The same one whose guidance computer has a persistent habit of failing during re-entry resulting in the vehicle making a high-G ballistic re-entry? Seriously, the reliability of both Soyuz (the booster) and Soyuz (the capsule) is vastly overrated and it's reputation doesn't survive shifting from handwaving claims like "most reliable ever" to examining the actual numbers.

Thanks! I really need to get back to that and my planned 'round-the-world flight... But I got distracted by other stuff.