A science transmitting question

[RonnieThePotato]

This is my first time playing career mode, and I'm wondering if I bring two of the same experiment and transmit both, will I get the same amount of science that I would get if I recovered one experiment. Or would I have to send another mission to recover the other half of the science. I'm planning a lunar fly by and I just need to know.

[bewing]

You never get as much science through transmission as you do through recovery -- except for EVA reports and Crew reports. For those, you get full credit on the first transmission. For some others, each additional experiment that you get back to KSC (no matter how) will give you an incrementally smaller boost. Generally, it's worth transmitting one copy of the experiment (then resetting the experiment, if necessary) and then redoing the experiment and recovering that second copy of it.

[WanderingKid]

There are pros to bringing along multiple copies of the same experiment, even on a simple flyby (but only two).  If you don't have a scientist on board who can grab the data and reset the experiment (Materials Bay and Goo) bringing along one for both high and low space flight can let you get a larger science recovery then doing both in the same biome. 

For example, the Goo Bay gets 10 units of science per experiment (leaving out biome multipliers here).  Maximum value per biome is 13.  Transmission efficiency is 30%.  So, to expand on what Bewing said above, transmitting 30% of 10 (3 units) and then resetting the experiment with a scientist and recovering it will max out that biome in a single pass, bringing you up to 13 units.  Mat Bay is similar.

However, if you don't have a scientist to reset the experiment, you'll need two goos to get the full 13 units of science from the biome.  Better, though, would be to use those two goos to get 10 from high, and 10 from low, and get 20 total science from the trip, instead of 13.  To get full science without a scientist to reset, you'd need 4 goo canisters, 2 for each biome, for a total of 26.  Usually not worth the weight.

[Foxster]

9 hours ago, RonnieThePotato said:

This is my first time playing career mode, and I'm wondering if I bring two of the same experiment and transmit both, will I get the same amount of science that I would get if I recovered one experiment. Or would I have to send another mission to recover the other half of the science. I'm planning a lunar fly by and I just need to know.

Nope. The second transmission gets much less science than the first. Combined they yield less than recovery of the experiment. 

About the most you can suck out of a biome is to do all the experiments and transmit them, do them all again and transmit again, do them a third time and recover them.

The first transmission will yield another 5% science compared to recovery alone and the second transmission will give another 1% i.e. not really worth the bother. Whether you consider the extra cost/bother of making the craft capable of transmitting results (power generation, battery, aerial, relay) worthwhile is up to you. 

Whatever you decide, I strongly suggest using the mod "ForScience!". It runs any available experiments for you, resetting them as required if you have a scientist onboard. It won't cheat your way to more science than is available manually but it will ensure you get any science that is available without all the tedious clicking.