zeppelinmage

Tried designing a universal (~6km/s DV) lander... failed miserably. I think I need a new approach.

Exactly what I was looking for. Thank you!

A little background: I'm planning an interplanetary ship that'll be able to hit every body in the system. To test it out, I selected the Joolian system as it's first target. (Arguably, if I can hit everything there, I can hit everything everywhere. And coincidentally, be eligible for this challenge.) I've got a basic plan down in my head, I just need to see what I need to get it done. One of the problems I'm encountering is Laythe. I don't want to waste fuel doing a powered landing; I'd like to be able to parachute down. Now, my lander is going to be packing a lot of fuel weight, mainly because I plan to re-use it for every moon in the system (yes, even Tylo), refueling at the mothership. I'm worried that if I don't pack enough parachutes my lander will lithobrake too hard. I don't want to find that out the hard way once I get there. Thus my question... what's the weight limit on parachutes? Especially the Mk2-R Radial-Mount Parachute.

Part of my interplanetary mission includes a rover. So I slapped one together in like 30 minutes, just as an exercise. Sonbin and Bill couldn't help but try it out.

Had an Eve window open up, so I sent a probe out that way. And now I'm in the process of designing a manned interplanetary mission. One of those huge grand-tour type ships with landers and rovers and etc. Just have to start my back-of-envelope sketches and rough DV calculations. This is gonna take some homework to get right.

Well, I took a few days break from KSP... got a little burnt out. Today I loaded it back up. FFWD my Moho probe to it's correction burn... come to find out my orbital trajectory was going to miss it by quite a margin. Needed more than 7km/s to intercept. And my probe only had 2000. Fail. Oh well, kind of expected with my first interplanetary probe. My second mission was far more successful. Finally returned Bill home from a heliocentric orbit (after missing his burn point and slingshotting out of Kerbin SOI). He's very happy to be home, after 60 days chasing down the planet.

Yeah, I haven't been to Minmus in a while; since squeezing all the science out of it. After I posted, I recalled needing LESS fuel for a Minmus mission than a Mun mission. Either way, 9400 m/s wouldn't get me very far. Maybe a one-way to another planet, but certainly not round-trip.

Try fewer LV-T45s. I usually only connect 4 of them below my boosters (with ever-handy strut-clipping).

I'm also a bit of a n00b, but 9000 m/s isn't all that much. My Mun rockets usually end up in the 8000-9000 range, so this one would get me to Minmus. But I also design my rockets per stage... ie, a "lifter" stage, an "orbital/transfer" stage, then the "lander/return" stage. Just getting to orbit takes 4700-5000 m/s. Munar transfer is ~900, landing takes me almost 1000 (I do the same landing technique - bleed horizontal velocity to 0, then drop vertically), and returning back to Kerbin takes another 1000. IMO, the final delta-V matters far less than your individual stages and what they're designed to accomplish.

"14 km.", though most of it was via jetpack. Actual walking? Maybe a km or two. It was a month ago when I was still playing the Demo. Bill crash-landed on the Mun, so I sent Bob up with a rescue craft. The Rescue craft landed 14km away from him. So, instead of taking ages hoofing it, I used his jetpack. I was still rather new to all this, and ended up going quite fast over the ground. Probably on the order of 30-50m/s. Anyway, he got to the rescue craft quite quickly, and I tried to slow down for "landing"... To Bob's horror, Bill had a CFIT at a rather high rate of speed, less than a km from the lander. *poof*.

I finally unlocked the last of my Tech Tree. With 7 science left over.

Learning how to Plane. ...I think I might be going a bit fast. o.O

Rather graceful double recovery. Quite fitting after the fail-tastic Mun mission.

Oh, and that burn would take 6.624×1016 s, or two billion years!

My Jeb is currently in LKO manning a Duna Explorer waiting for his transfer window... in 220-odd days.

Even if it were possible in the realm of the game... Gilly is the smallest (lightest) body, at a whole 1.2420512×1014 t. To deorbit it at its slowest, that would take ~274 m/s of ÃŽâ€V. We'll use the motor with the largest Isp, the PB-ION, and assume we'll burn all of our fuel to perform the deorbit. ÃŽâ€V = Isp * g0 * ln (m0/mf) 274 = 4200 * 9.82 * ln (m0/1.2420512×1014) 274 = 41244 * ln (m0/1.2420512×1014) .007 = ln (m0/1.2420512×1014) 1.007 = m0/1.2420512×1014 1.250×1014 = m0 EDIT: Forgot to subtract. lol. Anyway, that's 794,880,000,000 t of fuel. Or, 159 trillion litres. Good luck assembling a rocket that large.

Built a rescue lander to rescue my stranded Kerbals. The mission was successful, insofar as I got the lander down within 5km of the crash site. I collected what SCIENCE I could, and hoofed it to the rescue. However, I cringed at the KER readouts. I had a whole 750 m/s of fuel left. >_< Apparently I burned through 1000 m/s just landing. I lifted off anyway, hoping against hope I could (LOL) have enough left over for a Kerbal return burn. Not so much. I got off the ground, circularized ~15km, and ran out of fuel. Now I have a Rescue for the Rescue in LKO about to rendezvous and get our intrepid heroes home. Even if it kills them.

After all that careful fuel planning... Teach me to try a night landing in a crater... without lights. >_< Though Sonbin and Jonwell seem overly pleased with the results. Now for the rescue mission for that juicy science!

Excellent, thanks! The first one is what I'm going for - at what point in my tank will I have exactly 1000m/s left. So, by conversion, that wold equate to 444L of total fuel, or 199.8L of the liquid portion. Yeah, the difference between "local" g and g0 is what confused me. I couldn't figure out if you used the g of your local body, or just 9.82ms-2. Local body made more sense (at the time) as I thought the force on the craft would change depending on what gravity you're fighting against. Rather than simply the force of the propellant out the back of the motor.

Balance, and fuel efficiency. I used to use 909s, but thought I'd try nukes this time around. And I can't fly a 2-motor ship stably, so I have to use 4. (In hindsight, I could have probably used 3...) But, I can't get the equation to behave. Basically, I'm trying to figure out how much fuel I need to keep in my tanks to be able to take off from the Mun and retrn to Kerbin. My math: ÃŽâ€V = Isp * g * ln(m0/mf) 1000 = 800 * 1.63 * ln(m0/16.36) 0.767 = ln(m0/16.36) e0.767 = m0/16.36 2.153 = m0/16.36 m0 = 16.36*2.153 m0 = 35.223 My ship is 22.36t and only has 6t of fuel on it. Kerbal Engineer says I currently have on the order of 2500m/s of ÃŽâ€V, so that doesn't match at all. If I add all the Isp together, that provides 3200s: ÃŽâ€V = Isp * g * ln(m0/mf) 1000 = 3200 * 1.63 * ln(m0/16.36) 0.192 = ln(m0/16.36) e0.192 = m0/16.36 1.211 = m0/16.36 m0 = 16.36*1.211 m0 = 19.817 Which comes out to 3.457t of fuel, or 691.467L (311L of liquid fuel). That makes a little more sense. Is that right?

EDIT: Crap, I chose the wrong numbers... stand by.

I have a lander in Munar orbit that has 4x nuke motors on. I need to calculate delta-V and burn time (specifically, the fuel mass required for a certain delta-V) for it. My question relates to how multiple motors work together. Do I add the Isp together? Average? Other? Fuel consumption would add, I would think?

History lesson from a meteorologist! Fahrenheit and Celsius scales were created independently in the 1700s, by dudes (shockingly) named Fahrenheit and Celsius. Fahrenheit built on a scale developed by Rømer, that had much smaller graduations between temperatures. (freezing point of brine = 0, human body temperature = 22). Fahrenheit multiplied them by a factor of four to increase the number of graduations and calibrated the focus temperatures (frozen brine, human body temperature) at 0 and 96, respectively. He also observed that the freezing point of pure water was 32, and the boiling point was at 212. (This will be important later.) Celsius based his scale entirely on pure water (instead of brine). Freezing point was 100, boiling point was 0. (I don't know why.) He had some scientific reasoning (p = RT) behind the scale, which is why it works so well with physics (and is the current SI unit). To make the scale more sane, the scale ended up reversing. As for the formula, that's pretty easy. It was derived later when scientists had a need to convert between the two scales. You'll notice the difference between freezing and boiling points of water for the Fahrenheit scale is 180. Divide that graduation by 100 for Celsius, and you get 1.8. Or, 9/5. So, to convert from Celsius to Fahrenheit, you multiply your Celsius number by 9/5 and add 32. You do the opposite for Fahrenheit (subtract 32 and multiply by 5/9).

The way I did a 6-ship kerbistationary constellation is this: 1) I launched one and set it at the desired altitude and period. 2) Launched my other 5 ships into circular orbits below the first. 3) I set the original satellite as my Target and used maneuver nodes to "aim" my satellite at its desired location. As I was still new to the game, I used a protractor for this, looking down on Kerbin. >_> Basically, since the target node will show you where the target will be, it's not too difficult to line them up at 60 degree intervals. 4) Circularize when you reach apoapsis with that satellite. 5) Use RCS (or ions) to fine-tune to your desired altitude and period (6h). That's without mods at all.

While building my station, I ran into a question. Namely, would a large mass (say, multiple orange tanks of fuel) unbalance a station in orbit? On either side of the refueling boom there are two packs of 5 jumbo orange tanks. All told, they'll hold 320t of fuel. The station itself is a whole 154t (dry). If I fill the tanks to capacity (they're currently empty), might it cause my station to become unbalanced? Also, if I fill the tanks non-symmetrically (say, fill the left before the right), might that cause issue? And finally, would the standard Clamp-o-Trons attaching them to the boom handle the mass? I suspect there shouldn't be any problems, but I want to be sure before I load them up.