DerekL1963

Mass I suspect - on a per Kerbal basis, a command seat is extraordinarily light. That (significantly) reduces the challenge of the challenge.

Though there are other reasons I won't talk about, one of the key reasons an ICBM RV enters pointy-end-first is that retaining as much of it's speed as possible as low as possible makes it much harder to intercept. They have more heating than you might think because they fly a very high arc, the information released after a recent test of a Trident-II indicated that it reached "more than twice the height of the ISS". That being said, back to Gemini... I suspect that since the area of the flat nose was such a small portion of the total that there was no particular reason to make it pointier, and since it was carried all the way to orbit they didn't want to make it heavier either.

In short, we already knew that.

Um, the two are not related... because you have to exit the capsule before you can use the zipline in the first place.

In reality? It's the same reason that nuclear submarines (which 99% of the time operate in areas where the bottom is far below crush depth) have escape hatches, and provisions for a rescue submarine to latch on. They keep congresscritters, mommas, wives, and girlfriends happy. None of us were under any illusion as to their actual usefulness. If we couldn't reach the surface and stay there, it was game over.

0.o

Serious leakage of fuel or oxidiser, a pad infrastructure fire, etc... etc... Slow disasters or moderate emergencies are uncommon in rocketry, but not impossible. No. You subject the crew to some pretty high G's and a potentially fairly rough landing.

Indeed. While it quotes costs per pound... it fails to compare capabilities. Raw cost-to-orbit isn't everything.

Presuming you're seeing the color correctly, to me it appears much brighter and more orange. (Hence my question about reflecting the light from the exhaust - you can also see the lower body of the vehicle glowing... evaluating this is not as simple as it appears at first blush) And we're also presuming the camera captured the relative brightness correctly. (As a photographer, not something I'd bet the rent money on.) There's a reason why blacksmiths practice and practice and practice - and when judging the temperature is critical, they do it in a darkened room if at all possible.

Chicken-and-egg. You can't blimp in the heavy equipment until you've already prepared a graded field to blimp it into, which requires heavy equipment to prepare... (You also require either very low winds or a fairly hefty mooring system.) If it's grassy/tundra, you can bootstrap, but a forest or significantly rocky surface is an entirely different game. And if you can get heavy equipment in to clear the field for a blimp, that just chips away at the justification for using a blimp in the first place. That's the real problem with the niche market emerging... remote enough that it makes sense to blimp in/out, yet hospitable enough that you can bootstrap. That's not going to be a common combination.

True - but the color of the incandescence varies with temperature independent of the composition of the metal.

The transition from mask-to-atmosphere involves two transitions (light (interior of mask)->heavy (material of mask) and then heavy (material of mask)->light (open atmosphere)), you're only accounting for one. (Not that frequency changes at a phase transition AIUI.) The EAB's drew from the compressed air banks and served via a regulator at atmospheric pressure, the air banks were charged from the open atmosphere. So, long version short - bog standard air at local pressure. (The boat's interior pressure could vary, usually *up*, from sea level pressure.)

Glowing red-hot - or reflecting the red-orange light from the engine exhaust?

I found the opposite when wearing an EAB... Everyone's voices seemed higher pitched than normal.

You still need thermal protection on the rest of the stage to protect from radiant heat.

There's no particular need to, none of the game changes affect the concepts here.

The first two items aren't maintenance, they're provisioning. And last example only covers stuff on the outside to connect stuff. None of those cover major work on the vehicle's systems, especially on the interior. ISS maintenance to date has been limited to routine preventative maintenance and occasional corrective maintenance (in the form of replacing LRU's). It's never had even a minor refit let alone serious systems level work of the nature that a Mars craft (which must operate for the better part of a decade without abort or escape capability) will require. (Especially after it's second of third trip when much of the machinery will be ageing.) In fact, the plan is that when it requires such a level of maintenance it will simply be disposed of. (Presuming it already hasn't been disposed of.) And the Gateway at a minimum adds something a Mars craft will almost certainly not have - the ability to dock (or berth) the multiple spacecraft required to support all of that work. (ISS currently has a Soyuz and two Progress docked, not too long ago it had those plus a Dragon.)

Since the use of the Senate Launch System and Orion is essentially mandatory... I don't why anyone would expect anything else. Seriously, people don't seem to grasp that NASA is not an independent actor - and that they have to work within the bounds of reality (while the fevered imaginations of the space fanboy are completely free of limits, let alone requiring any connection to reality). If you don't have a station... where are your maintenance crews going to live and how will they be supported? Where will the required tools, parts, and supplies be stored? What will provide support services for the vehicle while various systems are shut down and opened up for maintenance? There's a reason why practically every vehicle of land, sea, or air (especially modern, higher tech vehicles) have developed specialized support infrastructure for major maintenance rather than relying on organic assets.

No, not wrong. Just a difference in testing philosophy. Plenty of successful Jool-5 runs have been made using your method.

Certainly the chemical reactions he plans of using have been around for years and have been well tested - at laboratory scale on a laboratory workbench. The hard, and expensive, part however still lies in the future... designing, building, and validating flight capable hardware. And when you dig into the Case For Mars, you repeatedly find the same thing - "technology" used as a buzzword and a smokescreen to obscure the fact that almost everything the plan relies on doesn't actually exist as anything remotely resembling functional hardware.

I found it simpler to just Hyperedit the lander into orbit around the target moon and perform the test there rather than faffing about with non-standard hardware in a different environment.

The only relevant question is a bottom line, apples-to-apples comparison - can the vehicle perform it's designed mission? A complete Shuttle stack consists of an Orbiter, an ET, and a pair of SRB's. The Shuttle throws aways the ET, without which it cannot perform it's mission. A complete F9 stack consists of a first stage and a second stage. The F9 throws away it's second stage, without which it cannot perform it's mission. The F9, when treated as a stack (exactly as you treat the Shuttle), is exactly the same as the Shuttle - it throws away parts without which it cannot complete it's designed mission. Whether or not it can fire it's engines is irrelevant. Whether or not it can SSTO (in which case it's neither recoverable nor capable of performing the same mission as the F9) is irrelevant.

Since without a second stage, you can't deliver a payload - and the whole point of the vehicle is to deliver a payload, I'd say that yes it *is* a vital part. Yet, you seem to find it perfectly acceptable to deny that Falcon 9 is only partly reusable.

There's no particular reason to do so... all you'd do is spend a bunch of money on fuel and labor without accomplishing anything. But you could if you wanted to. (Easier to just burn the dollar bills in a fireplace though.) SpaceX throws a vital component away every mission too - the second stage.

After the first decade, the SSME's weren't overhauled at all - just removed for inspection. By the mid 90's, they were only removed for inspection every third flight or so. By the early 00's, they were only removed 'for cause'.