Any tips for going interplanetary?

[farmerben]

These issues will be no brainers to experienced players, but I'm a newbie like you who just started landing on Duna and Eve a few weeks ago.  

Communications networks and electrical systems can be the Achilles heel of these missions.  Solar panels are much weaker on Duna.  The mid-tier dish antennas are not always good enough.  And communications can consume way more electric charge than I took into account.  

The science probes I sent to Duna and Eve were only partially successful.  I couldn't transmit all the science back without running out of charge.  The workaround was to transmit results one by one.   For example, right clicking the thermometer and transmitting just thermometer data was successful... then waiting for charge to build up and doing the barometer, etc.  The atmospheric spectrometer instrument seems to have the largest data packets and I simply could not transmit that with the amount of electric charge I had.

I've got a Jool flyby probe with plenty of power and some mid-tier dish antennas (the flip down ones).  The antennas are not good enough.  I've got plenty of comsats near Kerbin, so the issue is range not line of sight.

 

The solutions are fairly obvious.   Had I been going to minimus or to look for asteroids in solar orbit, the technology onboard was adequate.  Going to other planets requires a lot more communications power.  Hope this helps.

 

[Skystorm]

You could also consider producing fuel in-situ (on site) if you plan to do much biome hopping.  It would require a small drill, small ore tank, and the mini-isru.

[Snark]

14 hours ago, farmerben said:

Solar panels are much weaker on Duna.

Sure, though unless you're trying to do something that requires high power levels over an extended period of time (e.g. drilling, or MPL research), it just means it takes a little longer to recharge, is all.

14 hours ago, farmerben said:

The mid-tier dish antennas are not always good enough.

True, but on the other hand, if it's a crewed mission, it doesn't necessarily matter all that much if communications are always up.

14 hours ago, farmerben said:

And communications can consume way more electric charge than I took into account. 

Were you using the RA-2 antenna, by any chance?  Those things are freakishly inefficient-- they require way more electricity-per-science-transmitted than the other antennas that are weaker or stronger.  Not sure if that's intentional or an accidental design goof.  If it's intentional, it's not clear to me why that one antenna is worse.

When I say "worse", I mean way worse:

• 2.66x more than the HG-5
• 2x more than the RA-15
• 4x more than the DTS-M1
• 3.6x more than the HG-55.

It's just off the charts.  Moral of the story:  If you need to transmit science and are using RA-2 antennas, carry way more batteries.

 

14 hours ago, farmerben said:

The workaround was to transmit results one by one.

Well, sure.  And that worked, right?  So, no problem, then?

(That's my normal mode of operation.  After all, as long as I can transmit one result, I can transmit all of them.  And there's no point in lugging around more batteries than necessary, it's just dead weight.  So I generally design my probes by considering how much electricity I'll need to transmit one result, and that's how much battery storage I put on, with a bit of safety margin.)

14 hours ago, farmerben said:

The atmospheric spectrometer instrument seems to have the largest data packets and I simply could not transmit that with the amount of electric charge I had.

Yeah, that one's a real hog.  It's by far the thirstiest of the science instruments.  Power needs will vary depending on what antenna you're using, but in general best to have at least 1500-2000 EC storage on the craft if you need to transmit this.  (Or double that, if you're using the RA-2.)

14 hours ago, farmerben said:

I've got a Jool flyby probe with plenty of power and some mid-tier dish antennas (the flip down ones).  The antennas are not good enough.

Yeah, for Jool you'll want the longer-range antennas.

You can boost the range a bit by spamming multiple antennas, but that's subject to diminishing returns.  Can be useful, though.  For example, if you've got the RA-15, spamming 7 of them (e.g. one on top, and two rings of 3) will combine to a net antenna power of about 64G, which is respectable.  So even if I don't have the 100G antennas yet, I can make an antenna-spamming relay sat and lob it in the general direction of Jool (or wherever).  Doesn't even particularly need to intercept Jool.  Then I can send my actual exploration vessel and give it a more lightweight antenna, because it only needs to reach the relay sat and not all the way back to Kerbin.

5 hours ago, Skystorm said:

You could also consider producing fuel in-situ (on site) if you plan to do much biome hopping.  It would require a small drill, small ore tank, and the mini-isru.

Yep, that can come in handy.  Though if you're planning on mining fuel, I've found that Ike is much friendlier to that than Duna itself is.  Much less dV, much lower gravity.

[MDZhB]

Just figured that I would mention that your planets don't have to be aligned to go interplanetary. In fact, you may find it easier (but much less efficient) to leave Kerbin's SOI, then intercept your target planet just like you would a space station or other docking target. I usually match inclination, then set a maneuver node at the right place. It will almost certainly take a lot more fuel, but if you're like me and you overbuild your missions, it works pretty well and you can launch any time. I never liked going interplanetary because I didn't like judging the angles by eye, and I didn't want to feel like "cheating" by getting something like Kerbal Alarm Clock to do it for me. Now that I know you can do it another way, I send many more interplanetary missions.

Edited July 18, 2018 by MDZhB

[Skystorm]

@Snark  Ordinarily, I would agree with you.  However, since he's biome hopping, and therefore already on Duna, he is using what would otherwise be the fuel he needs to get back to orbit.  He doesn't really have a choice but to mine on Duna.  Plus it allows him to extend his biome hopping indefinitely until ready to leave.

However, he could definitely stop by Ike on the way back to top off his tanks.  Being on Ike at that point will also make the return to Kerbin cost less since he's already in a higher orbit with nearly full tanks once leaving Ike's SOI.