Engine Question

[UberGamerKing]

Hey guys.

 

I have a spaceb station orbiting Kerbin at 150km. I want to send a shuttle to orbit the Mun, then head back.

I can have 2 engines, and I was thinking about the atomic ones, but they have really low thrust.

 

What would you recommend for a Kerbin escape and Mun orbit and return to Kerbin orbit.

I can refuel at the station, in case you were wondering.

[Aegolius13]

The Terrier is great for fairly small orbital shuttles.  It might actually be more fuel efficient than a nuke due to its lower mass.

If you want more thrust than a Terrier, the Poodle is about four times as powerful, and a bit more efficient.  But unless your shuttle is really big, the Poodle might be excessive.  You don't need all that much TWR once you've gotten to orbit.

[Guest]

Seconded. I use Terriers and Poodles unless there's a good reason to use something else (e.g. a design that requires radially-mounted engines, or a really small payload -- see below).

The nuclear engine is fantastic for big payloads and long distances (like sending a fully-stocked space station with lander and crew on an interplanetary mission), but for Mun/Minmus missions they're usually not worth it due to the mass and cost. Just use a Terrier or Poodle and pack a bit more fuel. (On interplanetary missions the TTW will be low, though, so your acceleration burn can easily last 15-20 minutes or so.)

Also, don't neglect the small engines: the much lower mass makes up for the somewhat lower efficiency if you're not going very far. I use Sparks for light local crewed missions and Ants for probes/satellites -- you'd be amazed at how far a minimal probe running on an Oscar and an Ant can go. I once used Sparks to return from Duna (I left my orbiter there and just flew the lander + extra crew module back).

[GoSlash27]

The Terrier and Poodle are more mass efficient for trips under 2km/sec and a whole lot cheaper as well.

Best,
-Slashy

[Warzouz]

LVN are useful for escape to Dres / Jool / Eeloo or Moho and/or big ships or when you need a lot of deltaV

[bewing]

It depends on if you are going to be reusing the ship. If all your spacecraft are use-once disposable things, then a cheap small engine is a good idea. If you are going to be reusing this thing dozens of times, then the efficiency of the nuke will easily pay for itself over time in fuel savings.