PnDB

Are you having difficulty landing in general, or just on Mun? If you're having difficulty landing on Mun and you've not landed anywhere else, you might want to practice landing on Minmus. The lower gravity is much more forgiving of errors, giving you more time to understand what types of maneuvers are needed to get on the ground in one piece.

Thanks, Padishar, for pointing out the "Atmosphere" button! I figured it had to be somehwere, I just couldn't find the darn thing!

First off, welcome back! Things have changed a bit since the transition to 1.0 and beyond. Launch methods that worked pre-1.0 don't necessarily work the same now. Landwalker, can you provide us an example of a rocket design that you use, and can you also describe how you currently launch it into orbit? We might be able to better determine how to help you with that information. Also, if you have not paid a visit to the Kerbal Space Program Wiki, you might want to take a look. Yes, some of the pages/tutorials on there are outdated, but the general concepts covering some of the things you want to do still apply... especially those things that don't involve atmospheres such as going places outside of Kerbin's sphere of influence. I have found Kerbal Engineer Redux to be incredibly helpful for understanding thrust to weight and delta-V. Definitely make use of its displays when designing rockets and when piloting them. Delta-V (dV), thrust to weight (TWR), and specific impulse (Isp) are all interrelated. I tend to think of them as follows: Delta-V: How much you can change your rocket's velocity (not necessarily just it's speed, as velocity is a combination of both speed and direction). A rocket with greater dV can do more "stuff". Thrust to weight: How quickly you can apply some of your delta-V. A rocket with a higher TWR can change its orbit more quickly. Specific impulse: Bang you get for your buck... how efficiently you burn fuel to apply your delta-V. A rocket with a higher Isp can do "stuff" with less fuel. To get into orbit around Kerbin, you need a rocket with on the order of 3500 dV. Add a bit more for piloting errors, and you end up around 4000 dV to get to low Kerbin orbit (LKO). As your piloting skills improve, this number will decrease a bit. If you're using a lot more dV than that to get into orbit, then you need to examine with a critical eye how you pilot yourself into orbit. "But how do I calculate my dV?" Well, you can look at the Tsiolkovsky Rocket Equation and crunch some numbers (I would recommend doing this a couple of times by hand to fully understand what's going on), or you could one of the game modes to compute it for you. MechJeb and Kerbal Engineer Redux come to mind. If you want to do something once you're in orbit, you will need more than 3500 dV. There are a number of dV maps available that tell you how much additional dV you need to get from one celestial body to another. For example, to go from LKO to a low Munar orbit, you will need around 1170 dV. This is in addition to what you used to launch yourself into LKO originally. When you plan to modify your orbit by placing a maneuver node, a bar appears next to your navball telling you how much dV that maneuver will cost. I have a contract satellite rocket with a dV of around 6500 that I use to complete pretty much any "position a satellite" contract that is around Kerbin, Mun, or Minmus. In some cases, I can complete two or more contracts with the same satellite. I also have in orbit around Kerbin, just waiting for a good transfer window for Duna/Ike. "How do I design a rocket that has more dV?" dV is related to the Isp of the current rocket stage and the current wet and dry masses of the rocket (wet mass is the rocket's mass including whatever fuel it currently has in it, dry mass is a rocket's mass excluding the current stage's fuel). So to end up with a higher dV you need to use an engine with a higher Isp, or make the ratio of wet mass to dry mass larger. Also important is TWR. If your thrust is less than your rocket's weight, you are not going into space today. In the Vehicle Assembly Building, each rocket engine lists its thrust at sea level on Kerbin (ASL) and in space (Vac.). When designing a rocket to get off the launchpad, use the ASL thrust values to determine TWR (Kerbal Engineer Redux appears to compute TWR using the Vac. number instead for some reason... maybe I missed a setting somewhere). The engine thrust values are listed in kilonewtons (kN). To compute your TWR, you need the weight of your rocket in the same units of kN. To obtain this, take your rocket's mass in metric tons and multiply it by the gravity of the celestial body you're on (9.81 kN/ton for Kerbin, I believe). Then simply divide the rocket's thrust by its weight, and you have TWR. If it's greater than 1.0, you can get off the launchpad. During launch you are fighting two things -- gravity and air resistance. The less time you spend getting to orbit, the better... you use less dV to gravity on your way up if you go quickly. "So why not just make my TWR something like 10.0 then?" Well, there's that other thing -- air resistance -- that you need to worry about. Air resistance increases as your speed increases, and (generally speaking... others will correct me, I'm sure) does so roughly as the the square of the speed increase... double your speed, and air resistance goes up by a factor of 4. A TWR of 10.0 would get you to supersonic speed before you reach 1000m off the launchpad, and you will experience a very strong drag force as a result. You end up using dV to fight the air resistance. As you ascend through the atmosphere, the air density decreases and so does the air resistance; getting out of the lower atmosphere before really piling on the speed helps. So you end up with a balancing act... you want to get to orbit quickly so that you don't use up too much dV fighting gravity, but you also don't want to get moving so quickly that you use up too much dV fighting air resistance. Tweaking your TWR up or down affects where you are in this balancing act. Try this experiment: Build a very simple rocket... a Mk1 Command Pod with a Mk16 Parachute on top, powered by an RT-5 "Flea" Solid Rocket Booster. In the Vehicle Assembly Building, right-click on the booster and set the thrust limiter to some value. Go and launch this test rocket straight up and see how high it goes. Then change the thrust limiter to some other value and repeat the test. You will find that you can get vastly different maximum altitudes, depending on what you set the thrust limiter to. You are effectively dialing up and down the rocket's TWR. Note that the rocket's dV remains constant at 650 m/s, no matter what you set the TWR to. When I did this experiment, I got the following results Limiter 100%, TWR 8.70, dV 650 m/s, 4457 m max altitude Limiter 10%, TWR 0.87, dV 650 m/s, 895 m max altitude Limiter 25%, TWR 2.17, dV 650 m/s, 5595 m max altitude With the thrust limiter set at 100%, I observed supersonic shockwave effects on the rocket before it even reached 1000 m. "Why did you end up with nearly 900 m for a max altitude when the launch TWR was less than 1.0? Shouldn't it have stayed on the launchpad?" Well, it did... for quite a while. As the solid fuel burned off, the rocket got lighter and lighter, and eventually the TWR climbed above 1.0, and up we went! Of course, around 2/3 of the fuel was burned sitting on the pad, fighting gravity and losing. It turned out that for this rocket, a launch TWR of 2.17 (thrust limiter at 25%) provided the greatest max altitude. Setting the thrust limiter even 0.5% on either side of 25% resulted in lower max altitudes. All three of these cases used the same 650 m/s dV, but the 2.17 TWR case found the minimum amount of dV lost fighting gravity and air resistance for that test rocket. TWR values higher than this ended up losing more dV fighting increased air resistance, while lower TWR values lost more dV fighting gravity. Different rocket designs will have different optimal TWR values for getting up out of the atmosphere and into orbit. There is no single perfect TWR number. For example, while the test rocket above liked a TWR of 2.17, my standard LKO tourist rocket would flip around backwards mid-flight if I tried to give it that TWR. It prefers a launch TWR around 1.35. People frequently toss around values between 1.2 and 2.0. Testing is the key here. Also worth noting is that your TWR constantly changes during your ascent, as you are burning fuel and thus losing mass. What started off as a TWR of 1.4 may well end up as a TWR of 3.0 by the time the fuel runs out unless you adjust the throttle somewhere along the way. Don't let your TWR get too high until you are out of the thicker parts of the atmosphere, or else you will end up going too fast and air resistance will teach you a lesson. So getting to orbit is a matter of sufficient dV and a TWR that gets you to orbit quickly, but doesn't go so fast that you lose a lot of dV moving air out of your way. Then all you need to do is follow a nice ascent profile (piloting skills). The ascent profile gets you up and out of the lower atmosphere promptly, so that you can start going faster, sooner. A nice ascent profile starts off vertical and ends with the rocket in orbit, travelling horizontally, all in one continuous smooth turn. As with TWR, different rockets will require different ascent profiles to maximize efficiency. Some are better off beginning the turn very early, while others need to go straight up a little longer before turning. It has a lot to do with the distribution of mass and drag sources on your rocket. Others have already posted a common ascent profile that works for lots of rocket designs (straight up to around 100 m/s velocity, then turn 5-10 degrees off vertical, and continue turning further and further, aiming for 45 degrees at about 15000 m altitude). By about 50-60 km you should be nearly horizontal, putting all your dV into increasing your orbital speed (going sideways rather than going up). Hope that helps a bit.

Janica Kerman got to take a trip around Kerbin with Jeb. "Hey guys! Yep, it's me, Jan, just back from the most... awesome... day... ever! I got to go on a trip around Kerbin with none other than Jebediah himself! How cool is that! Check it out! When we got back to KSC, I got to meet Valentina too! I told her when I grow up I want to be just like her and go into space!"

For simpler 3D printed parts (Pi housings, mounts for electronics, etc, even clockwork mechanisms), it's really a matter of personal preference; just about any of the freeware 3D modeling packages will do what you want. I would go ahead and start with Sketchup and see how far you can push things in terms of design. If you find you can't get something to work in Sketchup, see if Blender can do it instead. For particularly complicated objects, I've been using Rhinoceros v5 as my modeling package of choice. The downside is that Rhino costs dollars. Blender just couldn't handle the design of a 3D printable aircraft wing with internal trusswork, servo mounts, spar tubes and cable routing; Rhino didn't even break a sweat. I'm sure something like SolidWorks or Catia would have done equally well or far better, but at much higher price points.

Sorry to stray off topic, but I just read an article earlier today about a company that is now marketing a pair of glasses that help people with certain types of color blindness see a greater range of color. The glasses use spectral notch filters to selectively block the red/green overlap region, which is where many color blind people have difficulties. Pretty cool concept, though the glasses were a bit pricey. I believe the company was called EnChroma.

Northlight provided a very nice treatment of how to use the rocket equation to compute deltaV. As you use it, you may find that repeatedly computing deltaV by hand gets a bit tedious once you've got the hang of doing it. If so, there are at least a few mods to the game that automatically compute deltaV while you are constructing your rocket in the VAB, and also show you how much deltaV you have remaining during flight. MechJeb and Kerbal Engineer Redux are the first that come to mind. Also worth noting is that the rocket equation can get a bit complicated if you have a rocket which uses two or more different engines/boosters at the same time, especially if they burn out at different times during flight. It's not so much that it's harder to compute, it's just that you need to keep track of more things in your equations, and thus it becomes prone to error.

The C70 Mini MAK is primarily a spotting scope and should work nicely for daytime viewing of birds and other wildlife. For night viewing, it should work reasonably well for viewing stars and planets. Viewing diffuse sources like nebulae might be problematic due to the smaller aperture, though you should get decent results if you keep the magnification below about 20x. The ability to use other 1.25" eyepieces with it is a nice feature, as you can swap out the zoom eyepiece for a nice fixed-focal-length one optimized for whatever you want to view. For wide-field viewing, you would want something along the lines of a nice 35mm Plossl or if your wallet can stand it a 35mm ultrawide eyepiece. For basic planetary viewing with this Mini MAK you would want a 5mm or 10mm Orthoscopic eyepeice. Then you can fill in the middle with a 16mm eyepiece at some point, should the need arise. Nice thing about 1.25" eyepieces is that you can almost always use them on a future scope if you decide you want something different. And then there's filters to screw into the eyepieces to enhance contrast of particular planetary features, etc... you can get poor pretty fast if you go all-in on astro-viewing.

A couple: First, this link -- http://www.phys.ufl.edu/~det/phy2060/heavyboots.html Second, this...

You, sir, are a madman! Many points for style!

Please Squad, add more types of Kraken! We can then try to collect them all!

Stock install -- develops video issues (incorrect or blinking textures) after a couple of hours of play, and then freezes shortly thereafter when switching between crafts and/or KSC. If I don't quit soon enough, it freezes while trying to quit. Lightly modded install (KER and ScanSat) -- Same behavior as the stock install.

Jeb made it back into the command pod with 0.02 units of fuel left in his eva jetpack.

We saw the launch of IkeSat 1, a mapping/science satellite headed for Duna/Ike to fulfill a couple of contracts.

Strangely enough, deploying the chutes requires zero power. Also, the stack decoupler worked fine. We were completely out of power well before we crossed Mun's orbit, so I'm sure there was nothing left. I have visions of Jeb in the command pod with a hammer, hitting those explosive decoupling bolts and then reaching for the "Pull to Release" handle for the chutes.

AlexinTokyo, Steelsunoa, I think that's probably what happened. I did check the 2Hot thermometer at one point, and it must have been constantly displaying the temperature for the rest of the flight. I'm going to mark this one as Answered. Thanks guys.

Keldrek, I don't think the command pod by itself uses power. When I checked the various components on the craft by right clicking on them, nothing appeared powered up. Tsotha, I am certain that the SAS was off. I rarely use SAS unless I am landing or doing some other type of complex maneuver. Otherwise, I just let things drift. Alex, you might be on to something. What would it look like if I toggled the display of, say, the thermometer? Would there be some HUD that pops up, similar to how ScanSat shows the mini-map? I can't say I saw a display, though if it were small and off in a corner of the screen, then I suppose I could have missed it.

Greetings fellow Kerbonauts! Jeb was on his way to Minmus today to collect some ground samples and see once and for all if that little moon was in fact made of mint ice cream. Near the end of his transfer orbit, Jeb noticed that he has less electric power than he expected, and it was draining at a rate of less than 0.01 units per second. Seeing as the wonderful engineers back in the VAB saw fit not to include any solar panels on his craft ("we couldn't include any more parts!" they claimed), Jeb grumbled and continued with his mission, fully expecting to spend a little longer than planned on the surface of Minmus. After a significanly abbreviated visit to the surface, Jeb packed up his ground samples, stowed his EVA reports, and blasted back into space, hoping he could get home. Power continued to drain at an gradually increasing rate, now slightly more than 0.01 units per second. Burning to escape Minmus' SOI, Jeb realized he woud not have any power left for his next maneuver to return to Kerbin. As soon as his escape burn was completed, Jeb used what little power remained to aim himself in what he thought would be roughly retrograde once he left Minmus' SOI, and hoped the engines would still fire when he needed them. By a stroke of luck, he was pointed in nearly the right direction, completed a hard retrograde burn which would bring him into Kerbin's atmosphere on his return orbit. Jeb decided there would be a few... discussions... between him, Gene, and the engineers about this rocket design. So folks, I have no idea what would cause a 0.01 unit per second drain on power. I was not using SAS, the reaction wheels were idle. There was no power drain early in the mission unless I was making a maneuver. Any ideas as to what might be the culprit? The transfer rocket was very simple: Chute Command pod Decoupler FL-T800 tank LV-909 engine 2Hot thermometer Presmat barometer Kerbal Engineer Redux parts Do the science instruments drain continuous power, even if they are not being used? Jeb didn't get a chance to use either one on his quick trip to the surface. I don't recall seeing any power requirements for the science instruments or the KER parts. Thoughts?

Does Jeb have enough dV to make a safe Munar landing? Suicide burn in his EVA jetpack? Even if it didn't work, it would be a heck of a remembrance story for the folks back at KSC.

I sent a scansat probe to Minmus once, and planned to make an inclination change during transfer to come into a near-polar orbit, reaching Minmus close to its ascending node. Things were going fine until it was time for an inclination change, at which point I noticed I had no control over the probe. My solar panels were pointed toward Kerbol, but I had no power. Turns out I had been flying in the shadow of the Mun for a while, and my transfer orbit happened to line the probe up with the Mun rather nicely. I was surprised how long it took to get out of the Mun's shadow and get some power back. No worries, though, as I still had plenty of time later in the transfer to make adjustments to come in near-polar around Minmus. I have also self-shadowed all my solar panels before while in orbit around the Mun, pointing directly away from Kerbol. I had to wait until slightly later in the Mun's orbit to get a little bit of power and change my probe's orientation. Modified the probe design so that won't happen again.

I inadvertantly accepted a Kerbal rescue contract while I was in the same situation as you... no maneuver nodes. Here is what I did. The stranded Kerbal was in an orbit with Ap ~180km and Pe ~120km and slightly inclined (I missed the inclined part until mid-mission) I built a rocket with enough delta-V to get into orbit, do a bit of maneuvering, and have enough left to de-orbit. I also made sure there was space on board for an extra Kerbal... double-stacked command pods! 1. I launched and circularized into an 85km orbit. The Kerbal was significantly ahead of me in his orbit. Since I was lower than him, I just waited a few orbits to close the distance. 2. I then brought my Ap up to nearly 180 km, leaving my Pe around 85 km. I was still behind the Kerbal, so the low Pe still allowed me to catch up, albeit somewhat more slowly. 3. When I was getting "close enough", I brought my Pe up to nearly 120 km (still less than the Kerbal's Pe, though) to creep up on him. 4. At this point, I realized that his orbit was slightly inclined to mine, which explained why he kept flying north and south of me. 5. I matched inclination and matched his Ap and Pe as best as I could, and when he got within about 10 km of me, I selected him as the target. Now the navball displayed my velocity relative to the Kerbal. 6. I burned prograde/retrograde/norma/antinormal as needed to reduce our relative velocities. When our relative velocity was only a few m/s, I aimed toward the target and burned to close at about 10-20 m/s. 7. When the Kerbal came to within 2 km of me, I turned away from him and burned to drop our relative velocity, making adjustments for any lateral motion at the same time. 8. I then switched to the Kerbal using the [ and ] keys, activated his EVA jetpack using the R key, and then thrusted toward the rescue vessel. 9. I had to go back and forth between the Kerbal and the rescue vessel a couple of times to tweak our relative velocities and positions, and I also rolled the vessel to aim the hatch in the direction of the Kerbal for an easy ladder grab. 10. Once the Kerbal was safely onboard, I just pointed retrograde and burned for re-entry. It took about 2 hours of real time, and about 2 days of game time to complete the contract.

Thanks for the welcome! From reading the boards, it looks like there are many people here who are willing advise when folks run into difficulty. Maybe one day I will "grow up" to be one of them.

Wonderful story! I stayed up until 2 a.m. last night reading it, and I only got through the first 50 chapters or so. Spent another hour or so reading the final bits. Can't wait until the epilogue!

Greetings everyone. I had heard about KSP several times in the past, and each time I had forgotten about it before I could get around to downloading the demo. Well, that all changed about a week and a half ago when I finally remembered what had so often been forgotten. Wow. This is too much fun! I am now the proud owner of the full version of KSP, and have been playing in career mode. I've not yet made it beyond an orbit around Kerbin -- still doing bits of science, testing parts, etc. -- but it has been a blast so far. And then there was the rescue mission that I mis-clicked and accepted. Poor Enson Kerman decided to take a joyride in a rocket, and is now floating in orbit with no way home. Hmm... okay, Mission Control has been upgraded to level 2, but we don't have enough funds to upgrade the tracking station. Guess no maneuver nodes for this rescue. Just enough science to get the 909 engine and the BACC booster... can we make this work? Parachute, two command pods, a T400 tank, and a 909 engine for the rescue module. Decoupler, two T400s, and a T30 engine for the mid stage. Decoupler and a BACC booster for the initial lift. Liftoff! Man, this thing flies like a cow, really hard to turn at 10km, but we did manage to get into a nice circular orbit with plenty of fuel to spare in the rescue module. It took a little while, but we finally approximated poor Enson's slightly eccentric, slightly inclined orbit, crept up on him, and T+2 days later, Enson was able to EVA to the spare command pod we brought along and hitch a ride home... all without being able to place maneuver nodes. Jeb, our pilot extraordinaire, was doing a lot of math on his fingers that day. Splashed down in the ocean just east of KSC with about 2 units of electricity and almost zero fuel left. We were descending fast, even with the chute open at 500m, so Jeb burned up almost all the fuel in the last 100m or so, going for a soft landing to recover the engine and fuel tank. A slight bounce on splashdown, but everyone's home safe and sound. Way to go, Jeb! So many future plans, and so little time to actually spend playing, but it's going to be one heck of a ride!