Armchair Rocket Scientist

Pics would still be helpful, and possibly a flight log saying what failed first. Also try launching the same vehicle again with the same flight profile and seeing if it still fails. One possibility: as a rocket burns fuel, it gets lighter and its TWR increases. Real rockets often throttle down (or, in the case of multi-engine rockets like the Saturn V and Falcon 9, shut down some of their engines) close to stage burnout to prevent the acceleration getting high enough to cause structural failure. It's possible that this happened to your rocket.

Nope. Real nuclear-thermal rockets don't need oxidizer (although some designs can increase their thrust at the expense of Isp by inject oxidizer into the exhaust).

I see people crashing rockets on purpose for extra science.

Scramjets have gotten a vehicle pretty much built around the scramjets to just under mach 10, but that was with a B-52 to carry the thing and a rocket to get it up to hypersonic speeds so the scramjets would function. IIRC scramjets have a horrible TWR, so building a scramjet-powered vehicle that can cope with the weight and drag of rocket engines and fuel for the final ascent to orbit would be very difficult. If you want it to be reusable you need a heatshield which can withstand reentry from orbit, not just whatever speed the jets get it up to. If you want an SSTO you also have to carry some combination of ramjets, turbojets, or even more rocket fuel for takeoff and acceleration to mach 5 or so. So far, scramjets are hard enough to make work at all, let alone as a viable launch vehicle. Currently, technologies like pre-cooled jet engines (e.g. SABREs) and pulsedet engines getting a plane from zero to mach 5 with one set of airbreathing engines seems much more feasible than getting it to mach 10 on three.

Really, it's "only" the equivalent of 9 ram air intakes, since the radial intakes have a bit less surface area. Anyway, with that many intakes a turbojet + 2 48-7Ss could do the same thing for less weight

Partly. When you try to pitch up, your control surfaces are applying a downward force on your aircraft's tail, making the craft pivot around the axis of the wheels. The center of mass is on the other side of the wheels, exerting a downward force on the aircraft's nose. To pitch up, the torque from the control surfaces must exceed the torque from the aircraft's weight. Moving the wheels closer to the CoM and farther from the control surfaces makes the torque from the weight smaller and the torque from the control surfaces bigger, making it easier to lift the nose. However, if it's TOO close to the CoM, there is a risk of tailstrikes. You still have some room to move the wings back until the back of the root edge is flush with the back of the rocket fuel tanks. You can also replace your large control surfaces with 3 small ones, giving you extra pitch authority. I replicated your design with these modifications, but they move the CoL too far back. The plane takes off with ease, but has trouble keeping the nose up. Fortunately, a pair of structural wings mounted just forward of the others will improve that. This is true, but your wheels look far enough apart that if you aren't flipping out and crashing on the runway you should be fine.

There are some ideas on similar stuff in this thread: http://forum.kerbalspaceprogram.com/threads/56136-Rewriting-the-on-Rails-code Suggestions include: "don't unload craft with deployed parachutes at all" and "use an extremely simplified aerodynamic model to predict approximately where and how fast it will land" @Deathsoul097: The "probability of recovery" part sounds a bit too much like random failures. However, the cost of recovery being affected by the biome a craft lands in could work pretty well.

Hmm... this is sort of like an autopilot, which the What Not to Suggest list says the devs will not put in the game. Until 0.23 came out, I'd have said "Nah, not gonna happen." However, the RAPIER engine has automatic mode switching, which I don't see being any different than auto-shutdown for jets. By the way, Mechjeb has a "prevent flameouts" feature which auto-throttles jets. If the throttle starts decreasing of its own accord, you can shut down your jets.

The RAPIER has higher ISP than the LV-N in jet mode. So does every other jet engine. In rocket mode it's heavier than an LV-T45, with less thrust and lower ISP. Basically, the only application of the RAPIER is SSTOs, and even then its usefulness compared to a combination of turbojets and rocket engines is questionable. SSTOs designed for interplanetary flight without refueling tend to use LV-Ns for their transfer burns. A RAPIER might be useful for a Laythe lander, though.

As mentioned, all the wings in KSP are basically symmetrical airfoils, meaning that they produce no lift at 0 angle of attack. Real aircraft almost always use asymmetric airfoils for the main wings, but may use symmetrical airfoils for the control surfaces. They also typically have the front control surface at a higher angle of attack for stability reasons. The devs do have valid reasons for using symmetrical airfoils in KSP. A given part might be a main wing, a horizontal or vertical stabilizer, or rocket fin. In addition, wings may be mounted backwards (which would cause an asymmetric airfoil to produce negative lift). For an aircraft with a single vertical stabilizer, an asymmetric airfoil would produce sideways lift, making the plane difficult or impossible to control. If used as fins placed around a rocket with rotational symmetry, the lift produced would cause the rocket to roll - okay for spin-stabilized rockets, not okay for trying to do a gravity turn. Giving wings tweakable airfoil shapes could fix this in theory, but this would require a proper aerodynamic model and still be relatively hard to implement. Don't worry about that. Even flying at a 15 degree AoA, only about 3.4% of your thrust is "lost." You get a vertical thrust of 26% of the total thrust, but unless you have small wings and a really high TWR this is probably outweighed by aerodynamic lift.

At the moment, parts are not damaged or destroyed by aerodynamic forces (with the exception of solar panels). If/when a better aerodynamic model and reentry heating are implemented, the lander cans will likely be much more fragile than the capsules or cockpits.

When I saw the "Reindeer Replacements" bonus, my first thought was: "Nine Mainsails." My second thought was: "That's a great idea, I should build this." So here's Santa's new ride. A cluster of nine Mainsails, fueled by nearly 800 tons of holiday cheer. Its ambitious goal? Deliver 16 presents to the Big Pink Men who built the canals on Duna. Scientists say those canals were actually cobwebs on the telescope lens, which they forgot to clean, but who cares! Each present includes two mystery goo canisters for SCIENCE!tm, communications antennae, and a structural fuselage packed full of snacks and board games. Oh yeah, and parachutes. Total mass is 1.01 tons. And now, the mission highlights: To summarize: 16 presents (x20 to Duna)(+2 at night)(+5 Reindeer Replacements) = 327 presents delivered. Total is now 480 presents.

This is correct. FAR reduces the dV requirement to reach orbit from about 4.5 km/s to 3.5 km/s, which is pretty significant. On the other hand, the improved drag model can cause rockets to tumble out of control if you turn them too abruptly; this is worst with large or otherwise awkward ships. Stock rockets can easily reach orbit with 2 stages, and rocket-only SSTOS are possible at the expense of a very small payload fraction. KW rocketry doesn't change this. However, it includes 3.75m parts, which should make it possible to launch heavy payloads into orbit with a slightly smaller part count. In general, there are two types of mods for KSP: "new stuff" mods like KW rocketry or B9, which don't significantly affect the difficulty of the games, and "realism" mods like Deadly Reentry, FAR, or Realistic Solar System, which almost always make the game harder. In your case, I'd recommend you download a mod which tells you how much dV your vehicle has. Mechjeb and Kerbal Engineering Redux are the most popular. These don't save you any fuel, but they make it more likely that you'll pack enough for your mission. The only way to really "save" fuel in KSP is to fly as efficiently as possible. There are many tutorials on this out there. Mechjeb may also be helpful. The autopilot features aren't always the most efficient, but it's incredibly useful for tasks such as fine-tuning an aerobrake (landing guidance) and automatically throttling engines to keep you at terminal velocity or prevent asymmetric flameouts.

Actually, I think it's 0 presents due to the single-stage rule being violated.

Hmm... are sepatrons activated in the same stage as the decoupler, deorbiting the presents, allowed?

Just a clarification on one of the rules: If I drop a present from orbit, but focus on the present throughout reentry and landing, is it legal? Also, can presents have any onboard guidance and propulsion, e.g. RCS and a probe core for precision deorbiting?

Hmm... I'm guessing that the picture you have is of the rocket in 0.23. Mechjeb says you have a dV of 7073 m/s. The following dV maps: http://i.imgur.com/NKZhU57.png http://wiki.kerbalspaceprogram.com/w/images/7/73/KerbinDeltaVMap.png give requirements of 7110 and 7140 m/s for a Mun landing and return. Now, most dV maps include a safety factor, so that ship MIGHT pull off the mission if flown absolutely perfectly. However, I don't think the maps account for the time when your engines are running in atmosphere and have lower ISP. Also, your ship has no parachute, so you'd have to do a powered landing on Kerbin, which is at least another 100 m/s (atmospheric) with a suicide burn. Long story short, I don't think that ship can land on the Mun and return safely. What is the calculated dV from .21? Is it different?

Cockpit + rapier + 2 ram air intakes = 2060 m/s at over 30 km (with manual mode switching and engine throttled down to prevent flameouts). The plane had around 800 m/s once in a 100 km orbit... and a 4:1 TWR. Admittedly, I could probably have done the same thing with a turbojet and 2 48-7S engines. I can see these getting a lot of use on "rocket-style" SSTOs, but a spaceplane has no need for that much thrust outside the atmosphere. The Aeris 4A has about half as much thrust in rocket mode as jet mode, and there are people out there using RCS, nuclear engines, or ion engines as their entire "non-airbreathing" power source.

So far, the Surveyor program has sent probes into orbit around both of Kerbin's moons and all the inner planets. Kerbin's nearest neighbors have attracted the most scientific interest; Duna with its red, dusty, yet strangely Kerbin-like surface, and Eve with its thick, cloudy atmosphere and alien seas. The orbiters have already provided a treasure trove of data - for instance, Eve's seas are a mixture of hydrocarbons similar to rocket fuel, and definitely not drinkable - but sometimes nothing beats actually being there. As a result, Kerbal scientists developed the ADAM program. Its goal: to reach the surface of Eve. Two identical probes were built, each equipped with a variety of scientific instruments and extensively tested to make sure they could withstand the harsh conditions on Eve's surface (in a related story, Bob swears his hairdryer was stolen by someone in a lab coat. Bill and Jeb insist he simply lost it). The two probes were launched only hours apart, with ADAM 2 being wheeled out to the launch pad as soon as the concrete cooled. Both used an Athos launch vehicle, but with the SRBs replaced by two aerospike-powered boosters (no fuel crossfeed though: the Athos core stage lacks the necessary hardware). However, ADAM 2 actually beat its twin to Eve by several days - much to the relief of KSC staff, who were not looking forward to landing two probes at the same time. After performing a final correction burn to place its projected landing site in Eve's oceans, ADAM 2 jettisoned its interplanetary cruise stage and plunged into Eve's atmosphere. Even during the fiery reentry, the probe was collecting data, analyzing the plume of ionized gases surrounding the vehicle. Once slowed down sufficiently, it jettisoned the scorched remnants of its ablative heat shield, deployed its parachute, and came in for a gentle splashdown. ADAM 1's initial trajectory would have landed it in the ocean as well, but with ADAM 2's successful splashdown it instead put itself into a high orbit which would bring it down over land. Unfortunately, during the procedure a faulty command pointed the probe's solar panels away from the sun. By the time the mistake was realized, its batteries had died. Luckily, as it entered Eve's upper atmosphere aerodynamic forces forced it into a heatshield-first orientation and ripped away the cruise stage. A few minutes later, the little probe touched down safely on a hillside in Eve's highlands. Both probes are currently still operational, as is Surveyor Eve, which now acts as a data relay for them in addition to its primary mission. Next stop: Duna!

Launch Systems All the launch vehicles used by AASEA are based on the same basic concept: a fully reusable two stage rocket capable of reaching LKO and beyond. Any SRBs used separate only a few kilometers up and are recovered near KSC, while the first stage travels far out over the ocean. The second stage contains the "brains" of the vehicle, and can operate in space for several days thanks to its onboard solar panels. The heat shield is only rated for reentry from LKO, but by aerobraking to said orbit before its final reentry, the stage can fly as far out as the orbit of Minmus and safely return. Athos: The Athos is the smallest launch vehicle commonly used by AASEA, but has all the features and capabilities of its larger siblings. Its capacity to LKO is 1 ton. While small, this is enough to send probes as far away as Eve and Duna. Porthos: Porthos is the newest of the three launchers. It was developed to fill the gap in payload capacity between the Athos and Aramis. Much of its hardware is borrowed from its siblings, including 4 LVT-45 engines from Athos and two SRBs from Aramis. Aramis: With a capacity of up to 16 tons to LKO, depending on how many SRBs are used, Aramis is current AASEA's heaviest launch vehicle. Among other payloads, it has launched large communications satellites to KSO and Molniya orbits, and space station modules into LKO. For even larger payloads, an "Aramis Heavy" variant is being developed with two additional first stage cores cross-feeding fuel to the central one, providing a capacity of 27 tons to LKO.

Greetings, KSP Forums. The purpose of this thread is to create a public archive of the various missions and projects of the Armchair Aeronautics Space and Explosions Agency (AASEA). Our goals are as follows: 1. Be mostly realistic for serious missions. This means no sending kerbals on 5-year flights in a command seat or similar shenanigans. If roleplaying conflicts with the game mechanics, roleplaying wins. 2. Don't kill kerbals for no reason. This means sending probes to unknown destinations first, and no one-way trips. 3. Use reusable vehicles where possible. Mods used include: Mechjeb, Procedural Fairings, Procedural Wings, B9 Aerospace, and some edited config files.

For cosmetic reasons: I wanted it to look like a real GPS satellite. (They also weigh about the same adjusted for scale: real GPS satellites are a bit heavier than a Mercury spacecraft, my KPS satellites are a bit heavier than a MKI capsule).

All right, let's clear this up: Yes, planets can have retrograde rotation. Venus and Pluto both rotate the "wrong way." In both cases, the backwards rotation may have been caused by a collision. Moons can have retrograde orbits, though probably only if they are captured bodies. While many moons in are solar system are in retrograde orbits, all of them except Triton are tiny and very far from their parents. Also note that Triton's orbit is unstable; tidal drag will cause it to spiral in and collide with/break up inside the roche limit of Neptune in about a billion years. There are also a few planets with retrograde orbits, including http://en.wikipedia.org/wiki/WASP-17b. A binary protostar has also been found with part of the protoplanetary disc rotating in the opposite direction of the other part: http://en.wikipedia.org/wiki/IRAS_16293-2422

I happen to have done this before. Basically, build your launcher with all your satellites on it like so: Either launch to an LKO parking orbit and then burn to Kerbosynchronous Transfer Orbit, or launch directly to KTO. In either case, your apokee should be almost exactly 2868.75 km (the height of the final synchronous orbit). Next comes the tricky part. At apokee, you need to burn prograde until your orbital period is a particular integer ratio of the final orbital period. For example, the rocket in my picture is carrying 4 satellites, which are put 90 degrees apart. In my case, my orbital period was 3 hours (for a semisynchronous orbit), but for KSO your final orbital period will be exactly 6 hours. If I'm in an orbit with a period of 3/4 of that, or 4:30, and I release a satellite at apokee which instantly circularizes, then at my next apokee the satellite will have only orbited 270 degrees, leaving me 90 degrees ahead of it, perfect for releasing my second satellite. Alternately, I could make my orbital period 5:15, and release a satellite every two orbits. The closer you make your orbital periods, the longer it will take to release all your satellites, but the less dV they will need to circularize their orbits. KSP's map screen doesn't show you your orbital period. I strongly recommend using Mechjeb, Kerbal Flight Engineer, or another mod that gives you detailed orbital data. Alternately, given a desired apoapse and orbital period, you can calculate the desired periapse manually. Even with Mechjeb, you won't be able to get the satellites' orbits perfectly synchronized, and they will eventually drift out of alignment. Real satellites drift out of alignment too (though due to orbital perturbations and not floating point rounding errors), but they generally have someone watching them and sending commands for station-keeping burns etc. However, this is not how most KSP players like to spend their time. Instead, I recommend editing the save file after you get them in approximately the right orbit, and not touching them after that.

Not the most explosion-worthy, but I feel it's worthy of this thread. While testing whether my Iris launcher could deliver an Eve probe to a Kerbin escape trajectory, I placed the vehicle too low in the VAB. As a result, when the rocket took off, the main engine was left sitting on the pad. Needless to say, it did not go to space that day. Since the 20 ton rocket's only attitude control was now the built-in reaction wheels of two probe cores, I assumed it would imitate this year's Proton crash, but incredible it continued upward, straight as an arrow. The mission was "only a simulation" anyway, but out of curiosity I decided to see if I could save the rocket. Unfortunately, only when all the parachutes were fully deployed did I have the presence of mind to take a screenshot. Sadly, with full fuel tanks the first stage's parachutes were unable to slow it down to a safe speed, and the second stage crash-landed due to pilot error.