yurivonkerbin

Sorry, just to clarify; the 2,279 m/s is the minimum Orbital Delta V I would need to get into orbit (minus corrections for grav, atmo, sidereal), regardless of engine type. The RT-10 is just the first solid booster available so I naturally thought of using it. I suppose if the RT-10 only burns for 28 of the 43 seconds I need than it's giving me (4137 m/s / 43 * 28 =) 2,413.25 m/s, which is 58% of total m/s I require. However, if it makes more sense to use the T-30 with a stack of tanks, I will rework my calculations on design to use that. I suppose the T-30 is also better given the ability to throttle and cut-off a liquid engine as well. Thanks for the advice.

Oh wow, I was really off, wasn't I? Thanks for the link; I will take a browse through it and see what I can discern.

Okay, progress so far: Using good ol' fashioned pencil, paper and scientific calculator, I have so far determined that I need a Delta V of approximately 4136 m/s minimum to reach Kerbin Orbit. This is based on the total of the following (with numbers rounded up to the nearest m/s); - 2,279 m/s gross Delta V for orbit operations (before corrections of atmo, grav, safety) - 422 m/s for gravitational drag - 610 m/s for atmospheric drag (standard addition for Earth's atmo drag, according to sources) - 1,000 m/s safety margin - Minus 175 m/s sidereal rotation of Kerbin for a due east launch direction This roughly corresponds with the 4,500 m/s approx figure on the wiki, so I seem to have worked that out okay. My next problem is getting the thing into orbit in terms of fuel; - In my calculations, the RT-10 that I was planning to use as my launch stage (I am using the career mode and want to use only the parts I have available as I progress with research) has a thrust of 250,000 newtons and my current craft weight (RT-10 included) is coming out at 4,648kg. This results in an acceleration of 53.79 m/s (roughly 5.5 gees) based on the formula Acceleration = Thrust / Craft Mass. - This gives me a take-off duration of approximately 43 seconds based on the formula Take off Duration = Delta V for Orbit (m/s) / Craft Acceleration (m/s) based on the power of the RT-10 and the assumption that I use the Gross Delta V (2,279) in this calculation, not the total Delta V with all the grav, atmo and safety corrections. - However, the RT-10 empties the tank in approximately 28 seconds, leaving me 15 seconds short of the required burn time that (if I have worked this out correctly) I require at that engine thrust to get into orbit. So, do I therefore need a second stage? This is obviously going to increase the weight of the craft so I will have to do some re-calculation, but would I be looking at needing an upper stage based on a Liquid Fuel Engine (I believe the LV-T30 is available as a default part at the start of the career mode)? I really appreciate all the help so far on this; I was never really any good at maths when I was at school - despised it, in fact - but KSP has actually got me interested in having a go at learning and working this out for myself, so it's rather important to me to be able to calculate the majority of this to get a real sense of achievement for my first orbital accomplishment. Many thanks, fellow Kerbanauts!

Gotcha, I'll edit my calculator. Okay, so I need to pitch east on an orbit over Kerbin and subtract the surface velocity from the Delta V I need. The surface velocity; would that be the Sidereal Rotational Velocity listed on the Kerbin wiki page? Okay, so I have to add 2000 m/s to my final Delta V to take account of Gravity and Atmospheric losses. How is that actually worked out? I.e., how would I work that out if I was taking off from another planet with an atmosphere but different qualities of that atmosphere to Kerbin? Many thanks; I appreciate all of the assistance so far.

Ah, so the Planetary Radius should be the Orbital Radius I am aiming for?

Hi all, I'm working out some of the basic calculations for a ground-to-orbit insertion for Kerbin as one of my first challenges in KSP and I appear to be getting something wrong. Currently I am using the following calculation from the normally very useful 'Atomic Rocket' page on designing realistic space vehicles in science fiction: ÃŽâ€vo = sqrt[ (G * Pm) / Pr ] where: ÃŽâ€vo = deltaV to lift off into orbit or land on a planet from orbit (m/s) G = 0.00000000006673 or 6.673e-11 (gravitational constant) Pm = planet's mass (kg) Pr = planet's radius (m) sqrt[x] = square root of x Now, the KSP wiki says you need a Delta V of 4500 m/s for a stable orbit (mentioned on the Kerbin entry in paragraph 3) so I wanted to see if I could work it out myself and thus be satisfied my maths was correct. I worked it out by hand initially and was a little puzzled that I seemed to be coming out at a figure only around half of the 4.5km/s mentioned above. So I put together an Excel spreadsheet. As you can see below, the planetary mass and planetary radius are taken from the Kerbin entry on the wiki, and the gravitational constant is what I understand to be the standard one used in RL and in KSP; EDIT: Please note that 'Gm/Pr' should read 'GPM/Pr' to confirm where that calculation comes from. As you can see, my final calculation is still coming out only around half of the 4,500 m/s Delta V mentioned on the KSP wiki. Can anyone suggest what I'm doing wrong here? Many thanks for the assistance, I'd really like to be able to work this out.

Hi there, Just head about KSP through the grapevine and downloaded it the other day; absolutely hooked. So far I've only killed one astronaut whilst fiddling around in the demo, so finger's crossed for future survival rates! Have previously had some limited spaceflight simulator experience on the Orbiter simulator, but I very much enjoy the slightly more humorous slant of KSP, plus the ability to build your own spacecraft - I mean, how cool is that? So yeah, looking forward to getting to grips with the game in the future and interacting with the community, asking questions, sharing victories and disasters, etc. See you all in space!