On Tue, Aug 15, 2017 at 06:35:24PM +1000, Tim wrote:

> I'm certain that a ship could hover instead of setting down, in a way
> that addresses all the safety concerns in this thread and so on.  I
> just don't see yet what advantages that would offer.
>

Agreed, hovering isn't hard. We've been doing it with ships and boats
on Earth since ~ TL3. It's a solved problem.

And I see a potentially big disadvantage. The energy cost for a ship
to hover in the manner is:

     Energy = (m) * (g) * (h)

Where:

     m -- Mass of the ship.

     g -- Local acceleration due to gravity.

     h -- Distance from the surface (?) to the CG of the ship.

This energy gets paid for no matter how the ship "lands". If it's on
landing gear then the real landing gear is acting like a spring and
storing the energy from the compression force between the ship's CG
and the ground underneath it. Or, if it's hovering in this way it burns
fuel. How fast, I don't know [1]. But, burning fuel creates heat because
our power plant is entropic and that heat is gonna have to be carried
away by radiation and convection with the local atmosphere.

Looks like a starship operator has a choice here not of: "wear and
tear" vs. "no wear and tear", but rather of what wears out, the big
hunks of metal that are the landing struts, or the: fusion plant, heat
dissipation, and contra-grav circuits.

----------------------------------------

[1] I'm at work but I'll do a back of the envelope calculation when I
get home.

--
Chris

      __o          "All I was trying to do was get home from work."
    _`\<,_           -Rosa Parks
___(*)/_(*)____.___o____..___..o...________ooO..._____________________
Christopher Sean Hilton                    [chris/at/vindaloo/dot/com]