Well your science level should eliminate the need to actual visit nearby planets to scout them. Even our current level of technology allows astronomers to find distant planets calculate their size, mass, and their atmospheric composition, and make predictions on other features like that planet is a gas giant, that one is a mineral planet, that one could be made of diamond. If you can travel across interstellar space in reasonable time then you should have at least enough physics knowledge to identify what will be there when you arrive. Alien hyperspace radio signals would let you know that it was occupied.

You could have a send probe button. Essentially you paid small cost to send a scout drone to a system and it will provide a full account of all planets. Thus eliminating the need for scouts instead you pay the cost directly for each system you want to know about. The same approach could also be used to recon enemy worlds later on in the game.

On the flip side why not make explorer class ships super expensive? An explorer class ship would be one the biggest ships in your fleet able to operate far beyond your normal range with no support requirements. You might only build a couple of explorer class ships in a game. There purpose is to explore deep space and build new warp gates to add to your hyperspace network. They can travel in deep space and are not limited to normal travel lanes. As such isolated system off the normal travel lanes can only be reached and added to your empire by sending an explorer class ship there to build gate. They also can't be included in any fleets as other ships are unable to operate in places the explorers travel.

You could have a send probe button. Essentially you paid small cost to send a scout drone to a system and it will provide a full account of all planets. Thus eliminating the need for scouts instead you pay the cost directly for each system you want to know about. The same approach could also be used to recon enemy worlds later on in the game.

On the flip side why not make explorer class ships super expensive? An explorer class ship would be one the biggest ships in your fleet able to operate far beyond your normal range with no support requirements. You might only build a couple of explorer class ships in a game. There purpose is to explore deep space and build new warp gates to add to your hyperspace network. They can travel in deep space and are not limited to normal travel lanes. As such isolated system off the normal travel lanes can only be reached and added to your empire by sending an explorer class ship there to build gate. They also can't be included in any fleets as other ships are unable to operate in places the explorers travel.

Yes, players do wreak the most elegant design solutions :D Those bastards! :D

BTW, I love the "send probe button", it's so... cute and easy and elegant :D Only if I knew how to use it with regual fleets (that HAVE TO have an option to explore since they are physically entering the orbit of a planet).

Yes. Except one little "problem" The player can just send regular fleet there So, scouting can't be more expensive that using regular fleet (or no one will use that option).
Yes, players do wreak the most elegant design solutions Those bastards!

What I was thinking is that you have either or a combination of range and travel lanes. So your maximum fleet range is say 10 light years you can't send a ship beyond that unless you improve your fuel tech or build a colony which would then provide a 10 light year range around itself(standard 4x stuff) An explorer ship though has range of 10 or 20 times your maximum range. You can send one to investigate and chart worlds 200 light years a way and if they find a interesting planet you could plan your expansion to reach that world or invest in building a two way warp gate connecting that distant world to the warp gate network. Once in place you or any other race can reach your homeworld from that planet or any other planet in gate system. So you better make sure its not within range of any brain parasite planets if you can't guard the entrance.

BTW, I love the "send probe button", it's so... cute and easy and elegant Only if I knew how to use it with regual fleets (that HAVE TO have an option to explore since they are physically entering the orbit of a planet).

Glad you like it. What about not letting them explore? If a ship has a science lab it can survey any planet in a system for free or even does it automatically when it arrives. But fleets without science labs are simply unequipped to survey planets, and you can't colonize an unsurveyed planet. After all anything could be down there.

An explorer ship though has range of 10 or 20 times your maximum range. You can send one to investigate and chart worlds 200 light years a way and if they find a interesting planet you could plan your expansion to reach that world or invest in building a two way warp gate connecting that distant world to the warp gate network. Once in place you or any other race can reach your homeworld from that planet or any other planet in gate system. So you better make sure its not within range of any brain parasite planets if you can't guard the entrance.

But fleets without science labs are simply unequipped to survey planets, and you can't colonize an unsurveyed planet.

The primary feature is that you move ships/fleets between systems/planets. And when they enter such system you get some information (planet size, enemies, warp paths/lines). And... we can't remove this feature :) It would be confusing and annoying (like "no ship can enter a system that was not surveyed").

Plus, once you have the fleet/ship dragged to the system/planet, do you really want to click some button to make additional survey of the planet? I would not :D I feel, while I really like the "send probe button", I would not enjoy it as a player (first my fleet was moved there and now I have to probe the planet? it's basicly double work!)

I don't know, I'm kind of sceptical if there is an answer/solution to my question :)

The primary feature is that you move ships/fleets between systems/planets. And when they enter such system you get some information (planet size, enemies, warp paths/lines).

Why do you need to send a fleet there? Why not just give all that to player for free for all system in range?

Sending fleets to find out what's nearby is so 1492. :)

If the player can reach a star then they should know basic planet info, if any enemies have claimed part of the system, and what space lanes connect to it with out the need to send a scout ship. You might not know about the deadly space monster currently living there, or that there are ruins on the third moon of one of the planets, or if any planets are suitable for colonization but that's what probes are for.

Warpgates are really game changing. I don't think I would implement warpgates just so exploration can work Besides... in practice, wouldn't you rather colonize rich nearby planets? Proximity is proximity, you already have to defend the part of space near your homeworld (via invasion from nearby races that do not require any warpgate). As a player, I think distant colonization is a suicide (it's not about travel, it's about more hostile races you will be neighbouring).

It depends on your game set up. If stars are clustered into groups with large distances between clusters then Explorer class ships would act as a bridge allowing you to reach the nearby clusters which would otherwise be impossible without significantly upgrading your fuel technology.

Also explorers would be important if habitable worlds are uncommon or rare. At the start of the game you might only be able to colonize 1-5% of planets in the galaxy. On the rest the best you could do is build an outpost. In that way finding worlds to expand to is part of the early game challenge. There might only be one planet in range you can expand to from your homeworld there might not be any.

This also adds an interesting dynamic if different alien races have different habit requirements. Human's might by only able to colonize earth like planets at the start. But the Egon's can colonize Jupiter, Neptune, and Uranus, do you let them form colonies on otherwise worthless worlds to you? Do you place tariffs on them? Exchange cultures, share technology, enslave them with your fleet.

I don't have much to add, but do want to respond to one point:

What makes exploration in non-space games interesting? ...

Yeah, I think expolration is not fun in itself.

On this I strongly disagree: while I'm not sure about the fun of exploration in space games, I love exploration in other types of game: new vistas to see, new environments to explore and navigate and new discoveries to be made.

To give an example, while I was at university one little pass-time that I had was exploring some of the campus buildings that I didn't usually have much cause to go into. I loved seeing the various odd layouts, discovering what was to be found where, and so on.

I won't say that enjoyment of exploration is universal, simply because I doubt that there is a great proportion of experiences that do have a truly universal response, but I do think that for a significant number of people--myself included--exploration in and of itself can be a lot of fun.

Hmm... Thinking about that, perhaps a "black map" scenario might be better for exploration of star systems than the "fully revealed" options that have been suggested, with undiscovered planets and their potential resources and dangers being amongst the risks and rewards of exploration. It would probably also help if space weren't as... well... empty as it can seem, in order to encourage thoughts like "I wonder what's over that hill", or "what's that odd thing over there"--perhaps odd sensor readings might provike that sense of curiosity: "Commander, we're picking up anomalous neutrino bursts in that dead system over there! Should we investigate? It could be precursor technology activating--or it could be the local space monsters preparing for their next meal..." However, as has been pointed out, a black map might call for some serious handwaving in order to explain just why the map is black.

Sending fleets to find out what's nearby is so 1492.

Why not just give all that to player for free for all system in range?

You are to see all planet types, routes/space lanes, fleets present, allegiance of all planets/systems in scanning range of your colonies & outposts (and maybe in scanning range of fleets too). It also updates as long as within range (what if you lose a colony?)

But I have some problem with "range", I mean the fleet range. I was hoping for a mechanic where you are free to roam the galaxy far away from your colonies... So range would make no sense here. Ideas?

There would be also a second step, the "survey". Sending a team on the planet to dig around (to find artifacts, examine plants & animals, minerals survey, etc). You are not able to colonize a planet unless it was surveyed.

Let's say you have one imperial survey team only, normally they go around randomly (nearest planets first), unless you give a specific order "survey this planet".

And/or make 3 levels of survey (Basic (allows colonization, access to common minerals), Detailed (chance for artifacts and rare minerals), Thorough (shows everything))?

while I was at university one little pass-time that I had was exploring some of the campus buildings

Let me guess, you didn't have to build and manage small scout ships every turn to do so It's a different experience

True, but the question was of what made exploration fun in non-space games, and your answer seemed to be a statement that exploration wasn't fun in general; it was that latter, general statement that I was answering. :P

(Although it is amusing to imagine gathering first-year students to go out and explore for me, bringing back reports of their wanderings, and what hazards--angry lecturers, eldritch floorplans, and so on--they encountered on the way. Of course, not all return; and there are some places from which none return, leaving the question of whether to go oneself, or leave that place to whatever dark deadliness claimed so many first-years... ;P