[AR] Re: Weird question about SS-520
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Wed, 31 Aug 2022 02:53:16 -0400 (EDT)
On Wed, 31 Aug 2022, Aurthur Vimal wrote:
Why would a start up company go through heck of problem in developing a
liquid engine rather than try a solid rocket engine such as SSLV or SS
520 they both can put small sats in Orbit. Once they proved that they
could do it and have a source of launch income and then they could head
towards the Liquid. Am I missing something?
Unfortunately, the two solutions are not equivalent in important ways.
Notably, orbit injection by all-solid systems tends to be quite
inaccurate, which makes it unsuitable for a fair number of payloads.
There is also the question of who develops the *solids*. Yes, they too
need development, unless you are fortunate enough to find exactly what you
want in somebody's catalog, at a price you can afford. (Preferably in
*two* catalogs, from two different somebodies, so one motor supplier can't
just jack up his prices once you're committed... good luck on that.) They
are not as simple and straightforward as you might think; developing them
is expensive and takes specialized facilities.
Moreover, even with off-the-shelf motors, the corporate skills and
facilities needed for operations are somewhat different. So planning to
start with one and then switch to the other involves throwing away a
significant investment. There will be great temptation to postpone or
abandon that transition. Remember that the Shuttle SRBs were meant to be
only an interim booster technology, just to get things started until
something better could be developed...
That last is a particular problem if your long-term goals include
reusability and testability, which are what's needed to really bring costs
down and reliability up. You basically can't do that with solids.
The main reason why startup companies pursue liquids is that they don't
think solids lead anywhere that they want to go.
Henry
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