Thanks to Frank Morring’s Facebook post I see a video of the Spacex vertical landing flight.  While there is a lot of risk in this road to reusable launchers I see an unexpected advantage.  When retro rockets are firing, the first stage seems to be in an envelope of flame.  In actuality it is probably tucked in  an umbrella of cool provided by the shock wave of the rocket plume.  A capsule usually uses a flat heat shield to form a shock wave that better shields the sides of the capsule while taking the brunt of the heating head on.  The retro-rocket uses no shield, and suffers no direct contact with the reentry plasma.  This reminds me of Navy torpedoes that use super-cavitation.  They blow bubbles out the front that lubricates their underwater flow and allows huge velocity gains.

Perhaps we should be looking at both solutions.  Wings are reliable, but require a lot of heavy shielding to protect an orbiter in reentry.  A mild retro rocket system might induce just enough laminar flow to reduce thermal loads while also reducing forward velocity.  Now I know I want to have my cake and eat it too, but will we find a good tool here?  We may reach a balance that could survive a partial system failure without total disaster.  Retro failure might damage thermal shields without total mission loss.  Foreign object damage might not be as destructive in a laminar cooling flow.

Such a cooling flow notion was proposed many years back by an unlikely rocket guy.  Dr. James Victor Hugo Hill offered the Space Kitten as a kit plane you can build at home.  One ideas was to introduce a cooling gas across the leading edges of the vehicle.  Unfortunately (?) Dr. Hill passed away before this could take flight.   As one of his disillusioned early supporters I know there were many unresolved design ideas in the plan but this one might be vindicated some day.  Keep an eye on the crazy “rocket scientists” out there because some one has to be the first one dumb enough to try an idea before it can fly.




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