What Planets can this ship reach and orbit?

[Stickyhammy]

The picture shows how much fuel and oxidizer I have. I don't use add-ons or mods so I don't have a fancy readout of delta V. In case your too busy admiring my primitive ship and or station, the basic stats are 4 full orange jumbo cans and 2 full huge fuel cans. It adds up to 24480 fuel and 29920 oxidizer. This fuel powers 4 skipper engines and one KR-2L. I want to shoot for a planet, any planet, thats not Kerbin, achieve a stable low orbit, and return to Kerbin with my veteran crew. I would hate to lose Jeb as he has landed 17 times on the Mun and Minmus. Can I reach any planets with this fuel load or is the ship too small?

Edited June 9, 2014 by Stickyhammy
Fixed main engine type

[Jimbimbibble]

Well, it's sure got time giddy-up! That ship is massive. You should be able to get to Duna or Eve and back no problem. I wouldn't be surprised if it can get to Jool too. Just make sure you aerobrake when you get there.

[iStickyDuck]

I would say the ship is plenty big enough, it's the engines that are your downfall. If you are in sandbox or have unlocked most of the tech tree, use the LV-N Atomic Rocket Motors for all interplanetary missions and use as few as possible to keep the efficiency high. If you have not unlocked those, go for engines with lower thrust than what seems to be 2 Skippers and one of the new 3m engines

Hope I helped!

[Hodo]

Really can't tell you, what is the d/v on that craft?

I suggest getting KER for the information, it will tell you the delta velocity for that vehicle which will give you a good idea how far it can go.

[UmbralRaptor]

I would suggest looking over some of the ÃŽâ€V maps.

For actually finding a craft's ÃŽâ€V, mass ratios are more important then raw propellant numbers: ÃŽâ€V = 9.82 * Isp * ln(Wet_Mass/Dry_Mass)

It looks like you're treating it as 2 stages, which makes things slightly more complicated, but given the initial mass (check the map screen) should be calculable.

Assuming that you're firing the KR-2L and Skippers separately:

[table=width: 500]

[tr]

[td]Stage[/td]

[td]Isp[/td]

[td]Wet Mass[/td]

[td]Dry Mass[/td]

[/tr]

[tr]

[td]4[/td]

[td]350 s[/td]

[td]See map screen[/td]

[td]Wet_Mass4 - 128[/td]

[/tr]

[tr]

[td]3[/td]

[td]380 s[/td]

[td]Wet_Mass4 - ~160.1[/td]

[td]Wet_Mass4 - ~304.1[/td]

[/tr]

[/table]

Edited June 9, 2014 by UmbralRaptor

[Stickyhammy]

Well, I used the big engine on the main rocket because I figured I would need to use its boost to reach orbit. Turns out I had enough fuel in my vegetable tanks to get to orbit and reach the fueling station. I have enough landings to use the nuclear engine but its thrust seems so small.

As for mods and such, I could get something that would tell me the mass of my ship and all that but it just feels like cheating. I learn better if I need to figure things out by myself, or at least learn with whatever stock information the game gives me. I have been looking at the solar system map for about 30 minuets trying to figure out how to reach Eeloo. Might as well go for the hardest one to orbit so everything else is a piece of cake.

I think its the wrong time of year to get to Eeloo as the planet is almost on the other side of the sun. All my manuver nodes try to crash me into the sun or simply vanish when i alter the thurst icons too much. Green, purple or blue, its all Greek to me and I never only understand English. Since I learn by failing I think i will just point my ship towards Eeloo and hit the gas. Whatever happens happens

[Tex]

As for where it'll reach, we can't say for sure without knowing the Delta-V of the ship. However, once you do, you can also find a nice Delta-V map and see where it'll take you yourself!

[allmhuran]

If you're willing to be patient and to look into gravity slingshots, be aware that if you can get to Eve, you can use Eve to get to anywhere else just about for free. And that ship can definitely get to Eve.

For example, to get to Jool you first head to from kerbin to Eve (~1000m/s). Use Eve to push your apoapsis up near Duna (adjusting for this trajectory shouldn't cost more than maybe 50 m/s). Then plan a slingshot off Kerbin (another couple of dozen m/s for this adjustment) and your apoapsis will be between Dres and Jool. From this point you can burn for Jool at a cost of a couple of hundred of m/s, or you can loop around for another Kerbin slingshot that will push your apoapsis up to Jool.

[Pecan]

As you will have read, you NEED to know the ship's deltaV in order to determine where it can go. If you think mods are cheating and like doing the maths yourself it's not too hard - UmbralRaptor gave you the equation. Once you have that figure this list is in order of deltaV requirement (m/s) from Kerbin LKO:

Mun 1,170

Minmus 1,430

Ike 1,550

Duna 1,700

Eve 2,880

Gilly 2,950

Dres 3,860

Tylo 3,860

Vall 3,890

Pol 4,040

Laythe 4,360

Eeloo 4,790

Jool 5,170

Bop 5,920

Moho 6,640

Kerbol 33,680

Eeloo, as you can see, is not the hardest - that's Moho, or the sun itself if you count that. NB: these figures ignore potential for aerobraking and the order is different if you also want to land.

ETA: Oh - and you need to know WHEN to go as well: alexmoon.github.io/ksp/

Edited June 9, 2014 by Pecan

[Stickyhammy]

Well, I dont like math so I went ahead and got mechjeb. Its file is called mechjeb2 but i suppose its the right one. Put the entire mechjeb2 folder into kerbal space program gamedata folder and started it. Its career mode so I need to figure out what else i need to do to get it load the parts for mechjeb to add to my ship in the hanger. I vote that kerbal space program should give you this information without mods.

Edit: Started a sandbox mode to make sure its installed and yes it works. Have the mechjeb pod. Good to know.

Edit: This seems annoying. I guess I need to start a new career game to get the science tree to include the mechjeb pod. No thanks. I will just copy over the ship design to sandbox and check it there.

Edited June 9, 2014 by Stickyhammy

[Hodo]

Well, I dont like math so I went ahead and got mechjeb. Its file is called mechjeb2 but i suppose its the right one. Put the entire mechjeb2 folder into kerbal space program gamedata folder and started it. Its career mode so I need to figure out what else i need to do to get it load the parts for mechjeb to add to my ship in the hanger. I vote that kerbal space program should give you this information without mods.

Edit: Started a sandbox mode to make sure its installed and yes it works. Have the mechjeb pod. Good to know.

You may want to purchase the part from the science facility. It should be there.

[Pecan]

...I vote that kerbal space program should give you this information without mods.

:-) So did 80% of the rest of us in a recent forum poll, since it's essential for mission planning and ship design. KSP does show you the ISP and thrust of engines in the parts catalogue - and the total (wet) mass, but not in the VAB/SPH. You have to click Launch then change to map mode (M) from the flight screen, then click the 'i' information button at the mid-right of the screen. You'd have to subtract the mass of fuel manually to get dry mass. Calculating the ship's TWR is pretty easy: total thrust/(total mass * 9.8) but that is much less important once in orbit.

Go to the R&D centre to activate the MJ parts; assuming you've already unlocked the node where it lives you'll have to 'buy' it (free) there.

If you don't have any luck with MJ or just feel bad about using a mod any spreadsheet program and most calculators will be able to do the deltaV calc for you. The trouble with that is that whenever you make any change in the VAB/SPH you have to update the input figures in the spreadsheet, or whatever.

Edited June 9, 2014 by Pecan

[Stickyhammy]

I have all but the very last 550 science things unlocked in the science tree but I couldn't find mechjeb pod in anything I already bought. Oh well.

On the plus side I did manage to cobble together the ship with a mechjeb pod, 4 skipper engines and the big main engine. Mechjeb is telling me I have 8215 delta V. If thats accurate on the ship in space then I should have enough to get anywhere, except the sun I hear that place isnt very nice to close visitors. Something about flaming Kerbals.

Edit: I do have the box and it tells me delta V in the current game I am using. 8215 is accurate enough. I guess my question is answered I do find it funny that with all my ascent stuff on the delta v is only 11k. Seems like I should have more but meh.

Edited June 9, 2014 by Stickyhammy

[cantab]

For calculating manually:

Open the map screen, hit backspace to focus on the current ship, then click the i on the right. Read off the full mass.

Subtract the mass of the fuel AND the oxidizer available to the current stage. It's 5 kilos per unit.

Plug the full and dry masses into the rocket equation.

I recommend using only the KR-2L for your interplanetary burns, it's a fair bit more efficient than the Skipper. To shut the skippers down just right-click them.

[Red Iron Crown]

Remember that you need about 4500 m/s of dV to get into orbit in the first place. 8215 will be tight for some destinations.

Edit: Also, in the future I will be citing this thread as proof that the lack of a stock dV calculator leads to MechJeb use.

Edited June 9, 2014 by Red Iron Crown

[Pecan]

Edit: Also, in the future I will be citing this thread as proof that the lack of a stock dV calculator leads to MechJeb use.

LOL. We should, perhaps, mention that KER and VOID are popular alternatives. To quote my tutorial campaign, "important and sometimes vital information you need for designing vehicles, such as TWR and deltaV stats. There is a lot of overlap in what these can display so you only need one of them, but you may prefer more. KER is the most popular, VOID (anecdotally) the most accurate and MJ the most flexible, being an autopilot should you wish to use it for that."

@ Stickyhammy: Remember those figures are one way! If you want to come back you'll need to double them - which would limit you to Pol at most. You can aerobrake around Kerbin though of course, so there is a saving to be made there. On the outward leg your only options for aerobraking are Duna and Eve, but you have so much deltaV you can do those easily without it anyway.

Edited June 9, 2014 by Pecan

[Stickyhammy]

@ Stickyhammy: Remember those figures are one way! If you want to come back you'll need to double them

Yes I realized that thanks Just de-orbited my clunker after putting the fuel back in the station. Going to redesign a ship with those nuclear engines and see if I can get over 10k at station. It must have been the ships mass that cut so much off my available delta V.

[Red Iron Crown]

On the outward leg your only options for aerobraking are Duna and Eve, but you have so much deltaV you can do those easily without it anyway.

Jool and Laythe, too.

[Stickyhammy]

If I can figure out how to get it to space I think this ship should do the trick to get orbit data from all the planets. Thanks for all the help Kerbal Space Engineers! Yes It should be "interplanetary". Thanks for noticing.

[Red Iron Crown]

That's a low TWR, be prepared for long burn times. Sometimes better to break it into multiple burns.

[cantab]

KER is the most popular, VOID (anecdotally) the most accurate and MJ the most flexible, being an autopilot should you wish to use it for that."

VOID now uses the same calculation library as engineer, so they should be the same. My thoughts on the three:

Engineer Redux: Probably best for building, and good for in-flight info.

Mechjeb: Goes beyond basic info with its assistance and autopilot tools. Good for building and for in-flight info, but the power brings with it complexity.

VOID: Best for in-flight info with its HUD, displaying the key info tidily either side of the altimeter. Best I think for career since the HUD includes the current biome and situation, relevant for science. Not good for building since it only shows a stage at a time.

[Red Iron Crown]

The mods aren't either-or, as well. I like Engineer for building but MechJeb for in-flight, so I use both.

[Stickyhammy]

That's a low TWR, be prepared for long burn times. Sometimes better to break it into multiple burns.

I did get the ship into orbit and refueled at the station. Now your saying I needed more engines? But its already in orbit... Oh well. Back to the drawing board. At least these launches don't yet cost me any cash.

[Red Iron Crown]

No, no, not a deal breaker, just something you have to take into consideration when planning your next maneuver.

Say you're going to Duna and need a burn of 1100m/s, at that acceleration it'll take a 7 or 8 minute burn to do it, which may be enough to get you in a bad part of the orbit to complete the burn. So it might be better to split it into two 4 minute burns.

Duna's a nearby planet, ones further away will require bigger burns and almost certainly benefit from splitting the burn up into smaller segments.

[michaelhester07]

3 hours of burn time in a vacuum. You won't realize how long that is until you need to burn 1800dv to get to duna and the burn time is 45 minutes... and you can only physics warp 4x to drop it down to 9 minutes IRL.

I'd make her a little bigger and have liquid rocket boosters to boost you into solar orbit. 12000 dV gets you anywhere though.