[AR] Re: SSTO
- From: Craig Fink <webegood@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sun, 11 Feb 2018 14:13:18 -0600
On Sat, Feb 10, 2018 at 2:46 PM, William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
Today, I would want to carefully understand two technologies: very low
power thrusting during entry to provide a stand-off gas blanket (and
specially the mass of propellant required)
I too have been thinking about this one for a while, and seems to me to be
the way to go. If done right, I would think the mass penalty would be
minimal. But first, the vacuum engine bell has an expansion ratio that is
too large to operate deep in the atmosphere, but it will run just fine
without it's nozzle extension.
One solution fits
https://i.stack.imgur.com/uKx53.jpg
So, the extension needs to be replaced with a variable nozzle extension
similar to a jet, but designed for a rocket and able to open much wider
(even reversing) for the heat shield mode. The weight of the much heavier
variable nozzle extension could be mitigated by removing the engine gimbals
and traditional TVC and using the variable nozzle extension for ascent,
entry and atmospheric flight TVC. Increasing the expansion ratio of the
variable nozzle increase ascent performance, while providing additional
"wake shielding" of the tanks. The second stage could then land on the
engine to nozzle extension joint, so landing gear would not be required.
The "stand-off gas blanket" or film cooling of the variable nozzle
extension would be minimal for parts that are all ready built from high
temperature materials. I would think this type of entry would favor a short
high gee entry of a longer lifting low gee entry. The CG of the second
stage is at or near the engine resulting in a dynamically stable entry and
atmospheric flight. Plus, assent, entry and landing forces are all in the
same direction, the structure was built to handle load in the +X direction.
--
Craig Fink
WeBeGood@xxxxxxxxx
Other related posts:
