Come to think of it Mr Musk,

 

you don't need to send anyone down.

 

 

Just ready-made blocks will suffice.

 

Question is, how to get them fit.

 

 

 

A probe has to be dropped down to map the area.

 

This will serve two purpose,

 

 

to flatten out, to level the ground.

 

and to map the area is exact number/coordinates.

 

 

 

 

So if a sensor is attached to the cube,

 

it would know precisely where and which direction

 

the cube is allocated.

 

 

 

Then drop this down to that location,

 

without having to 'see'.

 

 

Rather it will be shown digitally, on screen.

 

As simulation (calculation) of numbers.

 

 

Whether the sensor will be able to handle the pressure of the water,

 

if allocated inside the middle of the cement, without breaking.

 

 

 

And sending signals 3000 meters above the surface, no idea.

 

 

Maybe it can be part of the rope instead.

 

The rope itself being electrical conduit -

 

and having integrated positioning system....