sevenperforce

Stock landing leg options really need an overhaul. They are so flimsy. I built my own pop-out Falcon 9 style landing legs the other day; they start folded, decouple and rotate down via action group when you hit G, and then lock into place. Fantastic impact resistance and no tipovers.

Make "Control From Here" apply to engines and to any stack decouplers, not just command units and ports. Make "Set as Target" apply to command units as well as docking ports. Make docking ports enable EVA.

Looking at this, it doesn't seem so: Looks like prograde/radial-in for initial entry, with a slow yaw to normal during ascent, then around to high AoA prograde during approach, followed by a pitchback to retrograde before main engines are ignited for the landing burn. Can't for the life of me figure out how it is supposed to work. The yaw maneuver looks like a controlled tailspin. It looks like they expect to do some kind of gliding pitch-up-to-stall to bleed off velocity, then drop through the stall (somehow), then pitch back. But with the heavy crew module up front and those winglets at the back, that thing should be a lawn dart. Maybe this is just the Mars entry version, where aerodynamic forces on approach are far lower, and they are doing something completely different at Earth EDL?

Random aside: does anyone have any idea how the proposed BFS is supposed to do the flip from prograde to retrograde for the landing burn? I've tried modeling it, and...yuck.

That's...crazy. Don't they already do this, essentially? They have a backup lifeboat on the ISS at all times, right? Though at present it's only the Soyuz....

Because at one time, it made sense to continue building SRBs and ETs, slap an interstage adapter on the top of the ET and a thrust frame on the bottom, and fly expendable. See DIRECT/Jupiter. "But Constellation!" they said. "But Altair!" And so THAT happened. Random: has an operational LAS ever been used for a cargo launch?

AFAIK, SpaceX has no plans to launch both crew and cargo on the same BFR flights, other than what can be flatpacked and accessible from the crew cabin. Admittedly, it doesn't make sense to send an LAS-equipped ship all the way to Mars. If you're on Mars, LAS doesn't help you much. If they ever launch people on the BFR, I would hope they build a short-duration crew-only version with a jettisonable crew cabin. Even if the upper stage engines can spool up and fire quickly enough to abort away from a first-stage RUD, this does nothing whatsoever to help in the event of an upper-stage malfunction. And yes, any such aux system will broadly impact payload capacity. But that's the price you pay for safety. I don't see blind criticism of the whole thing. I see a lot of people saying that the Shuttle should have been treated as an X project, with its lessons-learned integrated into a better system.

The last person who told me that I hadn't read the reports I'd read was a creationist. What, exactly, are you trying to prove here? While swinging wildly, the crippled SRB struck the right wing of the orbiter. We know it struck the right wing of the orbiter because the tiles recovered from the seafloor show the impact point. However, we also know that it did not rip the wing apart, because the right wing is visible in the footage, tumbling out of the smoke cloud. Did the SRB shear the wing off completely or simply weaken the structure so that it severed along the vehicle fuselage? We do not know. However, we do know this is the only place that the SRB struck the orbiter, and the subsequent destruction of the rest of the orbiter was due to aerodynamic forces, not due to direct impact by the SRB.

In theory, having a crew cabin which is an escape pod lifeboat with its own single-use ballistic-entry heat shield could obviate a large portion of the problem. Foam strikes could still result in LOV but they would have to strike the crew cabin directly in order to cause LOC...and at that point it would be a LOC during launch anyway.

Le sigh. The SRB clipped the orbiter wing. It dented the wing. Inertial and aerodynamic forces ripped the orbiter apart because it started tumbling, not because of impact damage. And all this misses @GoSlash27's point: if the crew is in on top of the rocket, a misbehaving SRB cannot hit them in the first place.

Speculative question: if the SRBs would have been given emergency blowout charges, to vent pressure and cut thrust (without a full FTS activation) in the event of an unrecoverable SRB problem, would it have even potentially helped Challenger? If the range safety officer had seen the right SRB's thrust dropping and gimbal correction exceeding recoverable limits, and pushed the button to blow out the pressure before the bearing strut failed, would that stack have maintained aerodynamic stability long enough for the orbiter to cut its engines and pull away gracefully? Seems unlikely, but at least it would have been a chance.

Word is they've already fixed the iffy launch clamp, and the last WDR saw full prop loading, so...ground ignition systems? Fuel pressures? It's anyone's guess.

If you don't want to put a door in your heat shield, then you can do an off-axis crew cabin with dorsal and ventral hatches. Internal hatch opens to internal crew passageway with airlock at cargo bay; external hatch available for docking or post-landing egress. Escape motors on either side of the crew cabin.

7 has been standard, it seems. You could get away with 4 or 5. Below that, and the per-seat launch cost goes through the roof.

Well, I was making it a LF abort system in stock. Making it smaller would not be a challenge. Cargo bay would typically be right under the crew compartment, for obvious reasons, but stock parts don't have a structural adapter for that. You do want a heat shield on the escape module, because Challenger. If the overall vehicle takes damage during ascent (or on orbit, due to meteoroid impact or whatever) that would render low-gee gliding re-entry risky, you ditch the orbiter and come in ballistic. Capsule heat shield is single-use. You can have a door through it to get to the airlock and cargo bay, if you like.

We may have to agree to disagree on this. Booster impact with the wing would be described as a structural impact force or a debris impact force. "Inertial forces" do not refer to impact. "Liberated RCS" did not blow anything up. The OMS/RCS propellant would not have been "liberated" until after the structural failures.

Err, no. "The destruction of the Orbiter occurred predominantly from aerodynamic and inertial forces that exceeded design limits." The RCS system ignition took place after the aerodynamic load caused structural failure in the orbiter which breached those tanks; it was not involved. No portion of the cabin showed damage from combustion products, flame, or debris; it merely ripped apart in the airstream. Virtually the entire cabin was recovered, and there was no positive indication that the cabin was breached prior to impact with the Atlantic. Depressurization or breach would have made it unlikely for the crew to take any action; the attempted activation of emergency oxygen was more likely the result of the impending vehicle destruction than a response to a depressurization event. If I was in the Shuttle and experienced it coming apart around me, I sure as hell wouldn't wait for the cabin to depressurize before grabbing for oxygen.

Not sure what he's angling at, either, but this is a good start to correct some common misconceptions: Liquid boosters can, at least, be throttled. One concern with adding a skin to prevent another Columbia was that then the skin could freeze, peel, and come off in even larger and more dangerous chunks. Liquid hydrogen is cold stuff.

Well, I hate to just come right out and disagree, but...I disagree. The orbiter was torqued to disintegration, not by the explosion, but by hitting an off-axis airstream that pushed it beyond its structural limits. The cabin did not disintegrate. The cabin was intact...and, potentially, not even breached...until impact with the Atlantic. Yes. SRBs were bad news. As I said before, if you'd replaced the SRBs with expendable dual-F-1 LFBs of equal size, the Shuttle would have had margins for days.

Bare tanks can be chuted down, but I doubt that leaves you with much payload other than the vehicle itself. Every tonne of engine you move from the orbiter to the drop tanks (making them boosters) is an extra tonne of payload to take into orbit. Of course, this only works if you go ahead and develop crossfeed...which, in real life, is much more complicated than just enabling the advanced gizmo in KSP. If you want to make it fully recoverable, there's a bit of a tradeoff; you can move engines to the drop tanks and allow them to land propulsively, increasing payload on the orbiter and saving the weight of chutes, or you can just chute the tanks, which hurts payload on the orbiter but means you don't have to reserve landing propellant. Thanks but no thanks, it does not meet any useful requirments. Wait, what? That architecture does everything the Shuttle could do, plus full recovery, 0-0 abort, and an independent crew capsule lifeboat.

If you wanted to build a reusable crew-and-cargo shuttle, today, it would probably come out looking something like this:

Chutes would have likely been far larger than the gigantic ones already on the SRBs.

"He flew that ship without wings all the way down."

This is so obvious.

It's one of my favorites in that sense, too. Super challenging to reproduce in KSP because of that. Unfortunately, ejection seats probably wouldn't have helped Challenger. Or any other RUD at any other part of the ascent. For one thing, the orbiter wasn't designed with a simple canopy that could be blown off for ejection. But, more to the point, any ejection during the SRB burn would have likely placed the ejected astronauts inside a field of burning solid-fuel particulates. No chute would survive that, let alone the astronauts themselves. Ejection after SRB burnout was too late, as they'd hit the atmosphere far too fast. Like a Falcon 9 first stage without an entry burn. The ET problem that destroyed Columbia was never actually fixed. They just basically hoped it wouldn't happen again.