wumpus

[edit: after testing this after Slashy's note, I should point out that while SRBs are great, I have to recommend liquid engines on top of SRBs even for suborbital launches. Re-entry [even going up] is just too dangerous for SRBs alone.] Note that the lowest level SRBs (flea and hammer) are fairly useless. The next two (thumper and kicker) can really supply the delta-v you need to get into space. By carefully mixing a thumper and LV-909 (terrier) you can send a kerbal into orbit (a 48-7S works much better, but isn't typically available for that first launch). Such rockets are wildly cheaper than the LV-T30 based machines. When you unlock kickers, you will likely no longer be interested in thumpers, but sometimes they are good for boosting small satellites into low orbits (along with 48-7S for circularization). A good thread for hints on kickers :http://forum.kerbalspaceprogram.com/index.php?/topic/122488-rules-of-thumb-for-building-cheap-and-cheerful-rockets/ Careful use of SRBs can leave you with a ton of funds that splurging on LV-T30 (don't forget the LV-T45: vectoring is often your friend, especially on unkerballed missions) might have eaten up.

If you go to the Smithsonian, when you walk in, SpaceShip 1 is to your right and the X-15 is out of sight*, but slightly to your left (and above) and near the escalators. But IRL spaceplanes only just touch space (yay!), not go into orbit. * or not (while the layout is pretty clear in my mind, I'm not sure what's blocked). Usually the other stuff in the entryway commands your attention and you see the X-15 when walking by it on the second floor.

There are two problems with airlaunch with unmodded KSP: First, once you leave the "physics bubble", you aircraft is deleted. Your launch vehicle either becomes a spaceplane or becomes single-use. Most kerbalnauts prefer to make their spaceplanes SSTO the payload as well. Note that there is a great mod for this (which might not work with 1.0.5 or be updated): http://kerbal.curseforge.com/projects/fmrs-v1-0-01 Second, all the air-breathing engines in KSP are OP. If you really want understand the issues with air-launches, you will likely need realism overhaul (and the mod listed above to reuse your airplane). If you don't want *any* mods, there is a quick and dirty way to get around this: build a first stage with solid rocket boosters that will burn with lots of thrust and a short burn time. You are looking for less than 500m/s of delta-v (less than 250 if you don't have drogues or otherwise want to make things easy on yourself). The trick involves the much larger "physics bubble" of 1.0.5 (or thereabouts) compared to earlier editions. WARNING: I am still working on this idea. Its more a side project that hit me when learning about the physics bubble change. NOTE: the following has NOTHING to do with air launch (aside from reusing the booster that eats most of the atmospheric drag), and has everything to do with not paying for the last (well first, but we build rockets back to front for a reason) 200-500m/s needed for orbit. Step 1: add a solid stage that will provide no more than ~500m/s of delta-v and will get there well before 10,000m. Step 2: slow the thing down. This could mean strapping flea rockets upside down to reverse thrust (and will be needed for extreme attempts at this). Add drogue chutes. These will slow down your booster and survive at 500m/s. Note that if you use flea rockets you are likely going to require "upside down" fins (but presumably the COM will be well above them. Put fins on the first stage and make sure they are below the COM as well). Step 3: make sure your chutes survive [UNTESTED]. Set the "partial deploy" altitude as low as possible. You need the drogue to slow the thing down to 250m/s or the main chute will not survive. You also need the chute to go fast enough toward the ground to get there before the main rocket goes over 22km. This means more aggressive rockets have to stage well before 10km. Step 4: Make sure all stages (decoupler, retrorockets, drogue, chute) fire at once (you lose control of it after you stage it). If you are using landing gear, deploy that first (it probably won't make a difference if you deploy it on the pad). Note that there are two options. Pad landing and sea landing. Pad landing is straight up and requires gear, but give 100% returns. Sea landing allows a pitchover (gravity turn) and puts you on course for the next stage. I'd recommend the sea landing, especially if you are trying for higher speeds (which will have less control. Note that horizontal distance counts, so don't lose your rocket because it is 10km up but 20km down stream... Finally, don't be afraid to make both stage-0 and stage-1 solid rockets. They might not be the most efficient by mass, but they are often wildly more efficient by price (especially stage-1 which isn't coming back). This doesn't impart enough delta-v to support the "don't lift solid rockets into space" rules. Liquid might work best, or solid might work best.

But it's nowhere near the massive scaling (or more likely complete irrelevance of earlier work) for SSTO.

Oddly enough, my experiences with adjusting rockets left me with the amounts of delta-v left [note these TWRs are limited in the VAB and flown pegged at the new limited "max"]. TWR - deltaV leftover in orbit. 1.25 - 123 m/s 1.51 - 287 m/s 1.67 - 294 m/s 1.75 - 304 m/s 2.00 - 308 m/s 2.27 - 305 m/s One thing that must be noticed is that this involves a rocket *capable* of leaving the pad at 2.27g. It obviously makes more sense to use a lighter engine that will only produce ~1.75g (or less), if such an engine is available. It just makes no sense to throttle down a rocket that makes less than 2.0g for any reason other than ease of rocket control: Throttling down will simply cause higher aero losses. Note that I've had "kicker" SRBs explode at roughly this [initial] acceleration (>2.1g), so be careful. It also isn't terribly significant as you are burning ~3000m/s to get there, so these vary just a few tenths of a percent of efficiency (while the control issues can be significant: I couldn't use mechjeb for launches to get this data).

I'm pretty sure it is an XBox1 (or a PS4, most of the difference is in the clock rates and GPU). Only specially sourced mobile processors have less CPU grunt than one of these. You might get away with less GPU specs (especially if you play less than at 1080 resolution). I'm reasonably certain the minimum [GPU] specs won't go up and you could just change the settings to match the old game. I was planning on upgrading the whole rig for Occulus Rift, but with the pricing shock and wondering how it will compare to value's system (and possible others), it looks like it can wait. Note that the clear winner for KSP<1.1 is probably an overclocked Pentium G3258 (newegg has them for $70), especially for the price. With 1.1, it should be able to stick any parallel threads on the second processor. Don't expect machines with 4-8 threads to magically have less limits than the lowly 1.1 (it is rare that limiting factors scale linearly).

My feeling was that many people pointed to the cancellation of this program as a step backward into space. What I see is a study in things that might matter for NASA (odd, because it seems to be a DoD program) while kicking the main point (SSTO) down the road. As far as its cancellation killing a "viable spacecraft", that appears to be mostly wishful thinking. Regardless of the SSTO mission, going up ~10,000ft (~3,000m) seems little more than what the LEM trainer could do. In hindsight, it looks like the ideal "lego block" to build an orbital vehicle (mostly just because that's what I've seen recently work, which doesn't mean as much compared to working from first principles). Just scale one (or more) rockets vastly up to make a first stage (that could land on its own) and land the upper stage as well*. On the other hand, I'm pretty sure that plenty of early shuttle ideas did the same. The big advantage "multiple DC-ns" would have over "multiple X-33" would be mounting. I suspect this advantage might be far big enough for the DC-n to be clearly superior (but it looks like NASA really, really, liked spaceships that looked the "Buck Rodgers" of 1970s TV [looked like airplanes, and landed like airplanes] and not like the "Buck Rogers" of early movies [that looked like V-2s and landed tail first]). * well, with the type of money Congress is giving the SLS. Not with the amount of money DC-X got (which was small enough to be under Congressional scrutiny).

You might want to tell Elon Musk that. While the Merlin engine is relatively light (less than 1 ton), reports vary on how much fuel reserve is maintained for return, but it is somewhere between 30 and 60 tons. If there was no need for return, and spacex was willing to design yet another rocket engine, they could afford to build an engine heavier by a factor of 4 to 10 times heavier (the upper stage can't afford to be heavy). Of course, the dead weight is displacing fuel you could have (for an equal TWR), so there are real issues with the delta-v, but it is surprising just how little it matters (compared to upper stages where any dead weight kills you. Just look at the rocket equation and it's obvious ("dry weight"="dry weight + all upper stages") In Harvester's initial description of KSP to the Orbiter forums, he was trying to figure out ways to reduce the issues of orbital mechanics for game players. While he did find one way to make it easier (make the planet *much* smaller, which made all the rocket parts less than authentic), most of the lessons are pretty close [unfortunately, apropos to this thread, airbreathers are so inaccurate to not worth mentioning any experiences in this forum, SRBs are pretty poorly modeled as well. And don't ask about throttling]. But the lessons of the rocket equation are pretty good, and the issue with engine weights flow directly from the rocket equation.

Two issues: first if you want hypergolics as a primary fuel then you are committing to *many* heavy launches carrying nothing but hydrazine and equally nasty stuff. If I lived in Florida I wouldn't accept such launches (and not living there I would agree with the Floridians). Other issue: Boiloff. First, while I don't really expect zero-boiloff to work for LH, LOX really ought to work. The James Webb space telescope will use zero-boiloff helium cooling, that ought to prove that it can be done for helium. Oxygen should be a walk in the park next to helium. Pretty much any non-ultra-toxic non-cryogenic would have even worse ISPs (shuttle SRBs had 240 second ISPs, I'd expect that hybrid (rubberish/NO2) would be even worse). Solid motors would probably require hypergolics for correction burns, but hopefully not enough for an ecological catastrophe. I'd favor hybrids left in place by ion propulsion. LH/LOX might work. And I suspect that if it worked, LH4C/LOX wouldn't be significantly more difficult.

I've heard a bunch of comments about DC-X, poked through the wiki, and have to ask. What was the point? If the point was simply doing basic [rocket] science, then I will simply admit that it did well, and its ideas are bearing fruit. But it also looks like it was a plan for a real spaceship (presumably a shuttle replacement that we desperately need right now), and I don't think it had a prayer of becoming such. The real killer is that (at least the wiki claims) that it was supposed to have been a SSTO vehicle. This has been gone over a few times in this forum, and it just wouldn't work. The wiki also claimed that it was more an operations project than a technology one (great for NASA, it only took 3 flight controllers). This makes it clear that there was no real effort to make a "zero dry weight" vehicle needed for SSTO. On the other hand, that doesn't mean that somebody could have pointed out the obvious "why not make a bigger DC-X as a first stage". This is pretty much half the concept behind the Falcon (they had a budget of $100M, no real need to get all the way to orbit, and mostly the electronics SpaceX has*). Of course, if NASA (and congress) had committed to a shuttle replacement, they presumably could have coughed up the funding and the smarts to build an orbital DC-X. I'm just wondering if there was any idea behind a multiple-stage DC-n or other feasible means to orbit. Because there was no apparent reason to expect a SSTO to possibly work. * less than you would think. Mostly because latency can't get all that much lower while computing a bunch of [unscheduled] things is *much* faster. Rocket science mostly cares about the latency and getting the answers on time.

One thing I've learned from KSP is that engine weight for the lowest stages is surprisingly irrelevant. The complexity will probably keep this idea on the drawing board for a long, long, time. I expect it will take a real attempt to colonize space or other need for *lots* of lifters to get to the point that fuel efficient rockets matter. I'm also wondering if you could get just the same effect with a cheap SRB? Note that while KSP may have exponentially increased my understanding of orbital mechanics, I think it has increased my ignorance of SRBs (hint, they don't appear to be *anything* like KSP SRBs). My guess is that you might be able to get away with a single stage SRB, with high thrust and a short burn (removing the O-ring issues that doomed Challenger, and lowering transportation issues). Connecting it to the rocket might be a hoot (presumably some sturdy thing that would make sure all the thrust was evenly centered across the cross-section of the rocket). SRBs might not be cheap, but the NRE needed to make your aerospike would be astronomical.

I've been mucking about in KSP wondering if the new physics bubble and wondering if it would "feel" similar to this engine. Er, what? KSP recently enlarged the physics bubble in the atmosphere. It looks like you can recover an unmodded stage 1 as long as it goes under 500m/s (I might have this wrong, a lot depends on mucking with deployment altitudes of chutes. The 500m/s limit comes from the limit of a drogue chute) and lands before the rocket hits 20,000m. Since Kerbin has a delta-v requirement to LKO of ~3000 and Earth has a delta-v requirement of ~9000m/s to LEO, a KSP first stage that stops at 500m/s (500m/s delta-v plus most of your gravity losses) would correspond to about 1500m/s on Earth (about mach 5). While I'd expect such a beast to go quite a bit faster (don't ask me how to survive the compressive heating, I just launch kerbals), that isn't far off what you might expect. [Please ignore that a lot of such first stages are going to be SRBs or other high-thrust engines, if only to get to the correct speed at a low enough altitude to land before the physics bubble deletes them. The effect to the rest of the rocket was supposed to be similar, not the actual air-breathing stage.] Such an engine could certainly save a lot of fuel. Could it ever be cost effective? Even with the number of launches of the delta family? Can't tell you that. But trying out low-delta-v "free recovery" systems like this at least gives you an idea of what such a boost saves you.

It is even worse. According to relativity, suggesting a FTL solution to a space battle is *exactly* like saying "go back in time and shoot him before he shot at you". If you can avoid that (or work out a reason why it is acceptable), you are well on your way to a theory of everything that includes FTL. I've always liked that Star Trek included both FTL and causality violations from the start. I'm sure it was unintentional, but it at least gave them options of steering to harder science fiction.

The easiest way to tell (assuming it can stand on its own) is to put it on the launchpad. Click "control from here" on all the command modules (assuming there are more than one). If at any time you see "brown side up" (instead of blue), on the navball that control module is inverted. This also works for capsules that are angled around (I did this once for a science rover and it had to be steered "sideways").

I know there were claims (from the Smithsonian exhibit where I saw it) that the X-31 was unstable due to putting the control surfaces in front of the wings (canards), and it was only kept stable by 3 computers on board. Presumably the Rutan Varieze (that now is exhibited in the Uvar-Hazy center) was buried too deep and nobody noticed that it used its canards as controls (without computers). My guess is that the aero model still isn't "good enough" and that we typically design unstable aircraft just to get sufficient control. No idea how different "sufficient control" is in real life vs. KSP (third person makes flying harder).

I started a couple of months before .25, but played a lot of .18 (the old demo) over this Christmas holiday. Now that was pure kerbalness. No big rockets, just keep cranking up the asparagus level until you have plenty of delta-v for the Mun (note: not having Kerbal Engineer was *not* an improvement. Squad should include delta-v). I like 1.0.5 more, but the joy of pure kerbalness is something you need to go back to, when you are worried about contracts and leveling your kerbals, and stupid science bases*. * don't ask about the sunk time in stupid science bases. Just don't.

Have you unlocked the science? I have similar issues (and took a kerbal vacation due to spending way too much time recovering rockets when I didn't need the money). Look for science missions and unlock science - note: don't worry about contract rewards for science. They aren't enough to bother with while "soil sample" is great for science. Just don't get bogged down training your kerbals to be scientists before launching your science base. I've wasted more time getting that "science base" ready without a single direct launch that you wouldn't imagine... The game is "build, dream, fly". I'm pretty sure "contract complete" isn't in that movie at all, even if they make a remake.

That is bizarre. Did one fail tests at the last minute, of they just couldn't come up with a way to package 11 birds? I'm sure that space-x would be happy with a little more fuel for the return. I really doubt they planned on shipping ballast when they designed the satellites and mission, but I wonder when it changed.

If you like playing this way, you might want to look at [warning - from 1993] "Buzz Aldrin's Race Into Space". This stuck to only running the space program. After the company went bust, the program was open sourced (I don't think Dr. Adlrin's name was included). [warning: sourceforge is a site that attempts to inflict malware. You have been warned]. http://sourceforge.net/projects/raceintospace/

There is nothing interchangeable about delta-V and TWR. First of all, TWR only applies when you are in a gravity field and fighting against it (just thrusting prograde/retrograde won't change anything). Use TMR in such rants. Obviously, a full "Voyager" probe (with full capture everywhere) would be painful with even the low TMR you would get with a 10-20km/s delta-v (asparagus plenty of NERVs, please) (better yet, refuel on the way back from Moho). For absolute theoretical flights, it would be presumably for interstellar flight. You would have to make sure your craft could handle 4x physics time acceleration and let the thing burn overnight. Unfortunately, I couldn't find a mod with interstellar objects to discover, and at .0002C your craft isn't going to get anywhere (interstellar) fast. One thing that *does* matter with high deltaVs and low TMR, you won't get anywhere near that "official" delta-v that kerbal engineer lists. You can only kick in perigee until you hit escape velocity, then you are ejected out of the SOI, and you can't make your burns long enough to matter at such wimpy TMRs. Your best bet is calculating delta-v manually, or possibly using Gilly or something as "location".

That is assuming a satellite designer doesn't have a wish list of features and power levels a mile long that isn't brutally cut down by the realities of fitting in a specific payload. I'd be shocked silly if a few more tons of "stuff" (solar arrays, heat fins, whatever) that cranked up just the communications power a few more dB wouldn't be worth the millions needed to go from a Falcon9 to a Falcon-Heavy, assuming the Heavyweight was in the range of "typical" GTO launches. This hardly implies that such a market is all that elastic (I'm sure plenty of those with working satellites just want copies of known good satellites), but I also can't believe you couldn't build a more capable 20 ton satellite cheaper than you could build a 4.5 ton satellite. Judging by the prices quoted to make those things, I'd expect they are on the cutting edge (or I'm wrong and that *all* the money goes on "absolutely sure to work" and they are far more conservatively designed than you could imagine. Markets and designing for the customers needs make for weird situations.)

Oddly enough, I think this was only added in 1.0.5 (or 1.0.4) when Squad added "basic fins" to tech level 0. These parts *aren't* mil-spec/NASA-spec grade, they are good enough for "launch anything" and "wheezy jets" missions (ok, I like to use them on real missions. But if something explodes I don't have to look to see what it was).

Note that hitchhiker modules are fairly quickly obsoleted by either mark1 or mark2 crew cabins. Mark1 take two modules to hold 4 crew, but are lighter and vastly stronger (the mark1 modules are wildly cheaper. Mark2 are similar in cost, lighter and vastly stronger) . The only real downside is that 1.25m parts make the whole rocket more flimsy. I'm not quite certain when you get each item on the tech tree, but you should be pretty far along before you start carrying groups of 4 kerbals at a time.

Depends on what antimatter you make. I think the only antimatter containment I've heard of (except that it was years ago, don't know if anybody still cares to work on it) was a bunch of positrons in a cyclotron-type structure. They were held traveling in a ring. Presumably as long as you kept them in their ring (and don't touch *anything*) they would keep going. Things might be easiest if you could make anti-iron and hold it in place magnetically, but I don't think anybody can make much beyond positrons.

Solid rockets might not be that odd (the most primitive gunpowder types have existed for centuries). Also remember that the capsules need only survive re-entry into a planet with ~3km/s delta-v to LKO not ~9km/s to LEO. Also, I don't think a kerbal year is that long: Kerbin's rotation is a bit faster. If you want things to prepare, download and install the realism overhaul set of mods. It will just work. Otherwise just set the date at sometime in the 1950s and don't sweat the speed you advance at (it will match history about as well as the tiny ultra-dense planets match our solar system and kerbals match human biology).