Henry;
All reasonable concerns although I would be inclined to take 800 seconds at
a 5:1 T/W, which was ground tested about half a century ago. I’m aware
that using modern design tools and materials an improvement of that T/W to
10:1 appears possible, thus offering double the performance of NERVA.
I’m also aware that better is the enemy of good enough...a constant problem
at a certain space agency, for example.
Bill
On Tue, Aug 27, 2019 at 12:44 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Fri, 23 Aug 2019, William Claybaugh wrote:
All of which can be avoided by building a conservative NTR of around 800
seconds Isp and testing it at around 1000 km altitude...
On Tue, 27 Aug 2019, Henry Spencer wrote:
This, alas, I lack confidence in...
Oops, forgot the P.S.: even assuming that this rash development strategy
works, there is still the question of whether Isp=800s is actually a
useful system, given a very heavy engine, the complications and mass
overheads of LH2, and high development and production costs. Is a stage
built using this engine really sufficiently better than an aggressive
chemical-rocket design to be worth the extra trouble and expense?
At 2000s, I could buy it; at 800s, I have real doubts.
Henry
