sevenperforce

Funny how that works.

IIRC the fuel-rich start of the SSME is much less severe than the RS-68's.

Not entirely. You can send a lone Kerbal ahead to Minmus, mine a bunch of ore, and then launch your landing party to meet him low Eve orbit and do the refining there. If your contingency lander has chutes, then you can program them to open at a particular altitude, stage them, then deorbit the lander with a piloted vehicle and let the contingency lander land itself.

The fuel-rich start is a big part. It's also generally a bare-bones rocket engine; it doesn't have very robust subsystems and can't take much variation. The whole vehicle is generally single-fault or no-fault tolerant, whereas human-rating requires a blend of single-fault and double-fault tolerance. The engine controller is not terribly reliable, the engine itself is built with low structural margins, and fault detection (a critical element in human-rating because faults trigger aborts) is insufficiently redundant. NASA estimated that the each engine would need to have 86 kg of additional structural margin and parts. Here's NASA's report on human-rating the RS-68.

Delta IV cannot be man-rated. The RS-68s would have to be completely redesigned to meet NASA's criteria.

Different feed path from the tanks.

I think that the perigee of the target was low enough to enable fairly rapid deorbit, but the collision would have been violent enough to kick up the apogee of some of the debris. The debris will still deorbit in a matter of months, but until then it will cross the ISS's orbit and will vary considerably.

The challenge is now live! Thanks again to everyone who participated in the commentary and discussion of the mission. Re-read the rules carefully; I have tweaked a few parameters to enable some more creativity around mission planning. Good luck to all!

Let me just say I absolutely love the use of antennae for strutting on this. Very smooth work. And those foreplane elevators are perfect.

New Dunning after the first aircraft-to-carrier landing.

Bridenstine may be politically-motivated but I trust that if he states a bare fact, it's true. The idea of a 4" chunk of space debris catapulted up above the ISS orbit is terrifying. Impact with an object that large would shred an entire module in an instant. You need less than 30 m/s of dV to kick a piece of debris's apogee up to 400 km from a 300-km orbit. Kill vehicle impactor speed (relative) was probably well over 3 km/s. Really, really stupid.

I love how many updates we get.

And it may introduce more drag losses on ascent, which would have to be factored in. Regardless, those are whopping margins if Orion really does carry over 1.8 km/s. I have also seen non-NASA estimates that place Orion's dV at less than 1.4 km/s, at which point it makes a little more sense to demur.

You're right; I finally watched it in full. It's odd because I have FH+Orion completing lunar injection and return with nearly 700 m/s to spare: I mean, they're the rocket scientists, not me. Maybe Orion mass growth has cut back its onboard dV, or maybe they want bigger margins? But still, -74 m/s seems like a small difference between FHe and SLS. In any case, the fact that Bridenstine admits FHB5e can put ICPS+Orion+ESM into the same orbit as the SLS core and boosters really calls into question why we need the SLS core and boosters.

Some things never die.

EM-1 was planned to be a flyby only, so it wouldn't need fuel for orbit. And I believe it would have enough for a DRO anyway.

FH can send Orion to TLI without ICPS if Orion uses its own engine for the end of the burn.

I see where you're going with this.

Is that an image of FH from last year? I thought the new FH would have Block 5 legs.

If you want to use Hyperedit to launch from an altitude over 45 degrees, or simply launch directly into a Woomerang-accessible orbit from the KSC (per @Laie's idea), then that's fine. As long as your launch vehicle deposits your payload into an orbit inclined to 45 degrees (or more) then you earn Tilt-A-Whirl. There could be a mission configuration where you send a fifth poor bloke ahead of all the others, to Gilly, and have him mine there before you launch the four who will ultimately land. I will mess around a little with the rules to add for some leeway in these areas...keep an eye out. I don't want to ban the inflatable airlock just because some people don't have MH; if I did, I might also have to ban the Mastodon because it's great for large Eve lifters, and from there I'd just be banning the whole MH expansion. What if we say that the airlock can be used off-planet (to satisfy Room to Move) but that for atmospheric ascent or descent you still need an actual capsule if you don't want to use command seats? This would temper the advantage somewhat and is also fairly realistic, since the original inflatable airlock was intended for use only in orbit. Regarding clipping: I'm not too worried about it, honestly. If you're clipping for structural or aesthetic reasons, or to squeeze something just 2% more closely, it's no big deal. Just don't abuse it. If you find yourself cramming 43 Oscar-Bs into a small fairing or clipping engines wholly inside other engines, that's a bit much. I'll update the rule to clarify. It will still have some dependence on the honor system but will narrow the field a little.

Was reading up a little on carrier landings, prompted by the "747 carrier" thread, and found an article about a time they test-landed a freaking C-130 on a carrier. But of course that is an edge case. The biggest aircraft ever landed operationally on carriers is the C-2 Greyhound, with a max loaded weight of 22.4 tonnes. It occurred to me...an empty F9B5 stage is estimated at 22.5 tonnes. It has control surfaces, and AoA, and flies through the atmosphere before landing. If you think about it, then, that gives Of Course I Still Love You and Just Read The Instructions the auspicious honor of accepting the largest operational aircraft landings of any aircraft carriers in history.

Indeed, that is the goal. I tried to make the bonuses as balanced as possible based on my own mostly-heuristic experience with Eve. Pro Pilot is not intended to punish ISRU so much as it is intended to push users toward an Apollo architecture, to encourage people to send an additional Kerbal to hang out in Eve orbit. It also makes it challenging to do any orbital assembly beyond LKO because you need a pilot on both craft, potentially. Express Service is a more straightforward dig against ISRU than Pro Pilot. I don't see ISRU as such a huge advantage myself. A very small lifter with command seats has a pretty small payload and the total mass can be quite small if you aren't trying to get Beach Bum. At that scale the mass of an ISRU drill and converter and radiators and ore tanks and power might be a wash. Will fix. Simply because of the bulkiness of the airlock when inflated, I think it can be treated as habitable space, unless anyone argues otherwise.

Combining a Mk1 crew cabin with a single Mk2 command pod is 2.56 tonnes; you can drive it down to 2.32 tonnes if you stack two lander cans in place of the command pod. If you remove monoprop from the command pods you'll drive down mass further. Four seats, four kerbals (which add non-negligible mass in a seat), and a fairing mount is at least 0.64 tonnes plus the mass of the fairing itself. Battery and reaction wheels, which provide for you, add more mass. So it's definitely a disadvantage but not an insurmountable one. It would be to your advantage to incorporate that bonus with other bonuses to boost your score.

No stress -- this is why I opened it up to a development/comment phase before launching! I removed the command seat rule from Keiger Kounter, making it easier to earn that particular bonus. Note that Room to Move only requires extra cargo space during long cruises. Whether ISRU is used or not, the mass of the assembled stack will likely be dominated by the Eve ascent vehicle, since that's what needs to have the most impulse, and you don't need to triple up cargo pods in the ascent vehicle (at least, unless you are trying to combine Room to Move with Utter Insanity, which I do not recommend). So adding extra crew space to the return vehicle has very little impact on total stack mass.

Edited accordingly.