Geological survey ships

[Michael Sandy (OP)]

After watching a survey vessel surveying the outer Sol system asteroids I noticed that the time spent actually surveying was miniscule compared to the travel time.

So it hit me that the requirements of a Geo survey ship are very different whether they are surveying inner system terrestrial worlds from when they are survey smaller bodies.

For surveying planets and large collections of moons, you want ships that efficiently carry lots of sensors.

However, the outer system asteroid belts can take more time to survey than the entire rest of the system.  And for that job:

Rock Hopper class Science Vessel    1150 tons     95 Crew     295 BP      Signature 23-120
5217 km/s     Armour 1     Shields 0-0     Sensors 0/0/0/2     Damage Control 0-0
Supply 200  
Ion Engine PB-0 AR-0 (2)    Armour 0    Exp 5%

Advanced Geological Sensors (1)   2 Survey Points


will do the job as fast as:

Geo Survey Beagle class Science Vessel    2350 tons     205 Crew     699 BP      Signature 47-240
5106 km/s     Armour 1     Shields 0-0     Sensors 0/0/0/6     Damage Control 0-0
Supply 400  
Ion Engine PB-0 AR-0 (4)    Armour 0    Exp 5%

Advanced Geological Sensors (3)   6 Survey Points

or:
Geo Survey Viking class Science Vessel    3000 tons     260 Crew     910 BP      Signature 60-300
5000 km/s     Armour 1     Shields 0-0     Sensors 0/0/0/8     Damage Control 0-0
Supply 400  
Ion Engine PB-0 AR-0 (5)    Armour 0    Exp 5%

Advanced Geological Sensors (4)   8 Survey Points

can do the job.

Strategically, the larger survey vessels are more cost efficient in moving Survey Points long distance.  The Rock Hopper excels where the distance spent surveying is far greater than the distance getting to the system to be surveyed.

I like starting with Jump Efficiency 4 and size 60 Survey Jump Tenders with speed 5 kkm/s.

If you are starting with a system with an outer system asteroid belt, it is cost efficient to start with a mix of Rock Hoppers, which will have Default orders to survey the Asteroids, and larger survey ships which survey Planets and Moons only.

Later, if necessary, you can mothball the less efficient Rock Hoppers.  Of course, it is faster to unmothball the very small Rock Hoppers later.

[Michael Sandy (OP)]

After some experimenting, I have noticed a few things:

There are different things to optimize for in a survey.

With Geo survey vessels, if you do not watch them they will all head to the same closest planet and start survey its moons.  But efficiency for Geo survey is to have one survey ship survey an entire planet-moon system by itself, so there is no duplication of travel distance.

Same with warp point survey.  I have seen them get to the outer ring and the survey ships are leapfrogging each other.  You lose the savings of having multiple vessels because they increase their travel distance.

It is very simple to manage 2 ship warp surveys so that they do not overlaps.

But another efficiency concern is the ratio of travel time to survey time.  Ideally, you want the ship to be spending at least 30% of its in-system time surveying.  Preferably 50%.  A smaller ship with the same engines to instruments ratio will spend a larger percentage of time actually surveying.

The numbers I have been running suggest that there are serious efficiency points to both small survey ships and few survey ships per system.

If one pursues that path, you will have to have multiple survey operations going on at the same time, and need multiple survey tenders to check up on them.

There are some disadvantages of course.  Multiple concurrent things optimizes for the survey ships being active in surveying more of the time, but each survey takes longer.  And as the empire gets bigger the fact that each tender is minding survey operations in multiple systems means that they will be doing a lot of travelling between them, and there is the chance that you will miscalculate and have several survey vessels which are idle for a long time.

Also, while long surveys optimize for reducing the percentage of time spent travelling to new survey locations compared to surveying, a long survey also means a higher chance of ships suffering their last Engineering spare casualty with no tender to report it to.

There is, of course, a major exception to the small size ship paradigm.  If you have a +30  Survey officer, you want as big a ship as possible for them.  A 4 instrument ship with a +30 officer could be set the task of surveying the close together inner rings of Survey Points while 2 2 instrument ships surveyed the outer ring.

Or for Geo survey, you could have 1 ship rapidly survey a planet moon network and then move on, while Rock-Hoppers with 1 or 2 instruments surveyed the rest.

Note, I think that 1-instrument designs will be less practical in 0.5 because a 1-instrument ship with still have 6 HS budgeted for essential systems, and another 5 HS for armor. (crew, fuel, bridge, spares)  11 HS instead of the current 8 HS for that size ship.

Under 0.6, I think my survey tender will have 5 engines, size 60, have 5 fuel bunkers, escorting size 48 3-instrument survey ships that have 4 engines, same speed.  The 4 instrument survey ship with 5 engines comes in at 61 HS, unfortunately, so maybe a slightly larger tender is in order.

On a cost basis, engines start much cheaper than survey instruments, so I believe that survey ships should have more engines than survey instruments until the costs get closer.  As I said earlier, the greater percentage of time that a survey ship spends surveying, the better.  A higher speed means less time spent travelling, and more surveying.

[Michael Sandy (OP)]

I have been considering even higher engine/sensor ratios.  However, go that way and your survey tender has to get larger if it is going to keep up.

I have been running around with a survey fleet BP to survey tender BP ratio of about 7 to 1.  There have been some times that I got a bit jammed up due to lack of tender on scene, but it was pretty flexible.  I worry that with higher survey fleet speeds I'd need such large and expensive survey tenders that the survey cost to tender cost ratio means I can't have as many tenders as is convenient.

[Michael Sandy (OP)]

Because fuel consumption can now be tracked it is possible to calculate fairly quickly what percentage of time a survey ship is surveying, and what percentages of time moving.

I need to keep better track, but so far it seems that Grav Survey ships spend more time surveying, and Geo survey ships spend more time travelling.

Surveying styles can change over the game.

At the start of the game, all surveying assets are concentrated in one system.  This can be inefficient.  After the initial warp point survey, one option is to scatter survey assets through all the systems adjacent to the homeworld.  With several geo survey ships in one system you have to keep an eye on it so you don't have two or more geo survey ships going to the same planet moon group and then travelling again to both survey another planet moon group.  It would be more efficient if one survey ship surveys one planet moon group while another surveyed a planet moon group on the other side of the system or in another system.  Less duplication of travel distance.

But as survey fleets get further from the homeworld, they would get more separated in distance, so this scattered survey strategy would require more jump tenders than a more concentrated approach.

Also, while the scattered survey fleet is more economically efficient, it is horrible from military efficiency standpoint, as even putting decent sensors on each scattered survey ship will be expensive.  From a military standpoint, you would want at least two ships in any system that you have _any_ ships in, so that the distant one can detect and hopefully report back if something happens to the other one.

As engines get more powerful and more expensive, I expect survey ship sizes to creep up.  The key to survey ship efficiency is optimizing the ratio of time spent travelling to time spent surveying.  Not sure what the best ratio is, yet.