Getting probes to other planets?

[Xuixien]

Hey guys,

So I've pretty much mastered getting into LKO, changing my orbit, going to the Mun/Minmus, landing, returning, putting satellites into orbit around Mun/Minmus, intercepting asteroids, etc - pretty much at the point where I don't even need MechJeb anymore.

So now I want to start sending probes to other planets. My problem is getting enough DeltaV into a high enough orbit (1 million km) in order to timewarp for my transplanetary burn. Anyone got any ideas for this?

I've got a really cool probe idea I want to try - I really want to land this thing, it's kinda cool. I could always hyper edit it, but it's not as fun.

Edited October 3, 2015 by Xuixien

[Harry Rhodan]

So now I want to start sending probes to other planets. My problem is getting enough DeltaV into a high enough orbit (1 million km) in order to timewarp for my transplanetary burn. Anyone got any ideas for this?

Change to another craft or timewarp in the tracking station.

[Xuixien]

Change to another craft or timewarp in the tracking station.

Well neither of this help me get more DeltaV into orbit, but I think the solution may be ion engines (well, argon engines from a mod).

[RCgothic]

It's not difficult to give a small probe an insane amount of dv. What's the payload?

[Slam_Jones]

Ion engines have insanely high ISP but very low thrust. It's a good option if you don't mind babysitting your burns on 4x timewarp for 10 minutes

LV-N nuclear engines are also very efficient, but provide more power. They're also heavier, so really better suited for larger ships.

For a probe, though, an Ion engine is probably the best way to go. I recommend a mod like MechJeb or KER that will display your delta-V, if you don't have one already.

[Harry Rhodan]

Well neither of this help me get more DeltaV into orbit, but I think the solution may be ion engines (well, argon engines from a mod).

It does because you don't need to get into an extremely high orbit for an interplanetary burn. A burn near to the gravity well (LKO) is more efficient than one far from it.

[Razgriz1]

My problem is getting enough DeltaV into a high enough orbit (1 million km) in order to timewarp for my transplanetary burn.

Time warp while still on the launch pad (or the tracking station!) instead of in a parking orbit. This way, you can launch into LKO and then from there do an interplanetary burn, saving a large amount of DeltaV.

[Mastikator]

It only takes about 1100-1200 delta-v to get to Duna and 600 more to slow down if you do a good hoffman transfer. The problem is time and the more you wait the more you have to spend on both ends.

Landing on Duna is pretty easy too, use drogue chutes and regular chutes to slow down. The atmosphere is low enough that vacuum thrusters are still good (poodle/terrier) but high enough that parachutes can still be used. Landing a probe onto the surface of Duna is worth considering if you're going there, perhaps a satelite plus a lander probe. They don't have to be big.

Edited October 2, 2015 by Mastikator
more science

[mattssheep4]

A probe core, an FL-T400 tank, and an LV-909 can get you out to Jool easily once you get them into LKO. If you want something to return, you'll need a bit more though.

[ForScience6686]

I'm just starting to dabble in this myself. I would suggest your parking orbit be around 100km, you're wasting a lot of fuel parking way out there. Nukes have been my go to engine, but I have also used the poodle and 909. Just built a ship with over 6k dv and 4 nukes as I don't want to spend all day burning. It carries 9 probes, each one self de orbits, lands with parachute and packed with all the science goodies.

I had to pack extra dv as I'm not launching at the best times, but the transfer ship has enough to hit almost every planet if launched at the right time. I would recommend learning the rocket equation to calculate your dv before launch. This has drastically improved my missions and confidence.

What's the size of your payload? That will help determine what engines you can use.

[xebx]

An Okto probe Core and FL-T800 tank + LV 909 Terrier, you can have 4000 m/s to 6500 m/s deltaV for your probe. It's enough for all planets/moons.

(use fuel lines from the lateral jettisonable tanks to the center tank)

Ion engines are very good if you want very high deltaV (up to 20000 or 35000 m/s for fast travel for example), but they will have a lower thrust than LFO, so you need more planning of burn duration, timings etc.

Edited October 2, 2015 by xebx

[Xuixien]

This is what I came up with. Managed to do an Ike flyby.

Still a lot bigger than I wanted, but that's what I get for going with Argon Engines and not Ions. Ions would have been longer burns, though.

Thanks everyone for the help. Will be retrying this over and over to see just how small I can get the service stage.

[xebx]

Argon engines are Ion engines, just slightly different from Xenon.

For shorter burn duration add more engine (you will have less deltaV but still high)

Congrats for your first interplanetary probe.