Jeff Findley wrote on Tue, 17 Apr 2018
05:51:50 -0400:

In article ,
says...

JF Mezei wrote on Sun, 15 Apr 2018
20:35:30 -0400:

On 2018-04-14 20:52, Jeff Findley wrote:

I'm talking about today. SLS is bull$hit today. You don't allow
something this expensive and useless to keep on going due to decisions
made in the past based on assumptions that have changed.


But it can be argued that until SpaceX's manned Dragon flies
succesfully, it could be wise to continue NASA's manned rockets
development just in case. (what happens if Musk's business has to go
chapter 11, or some technical probvlem indefinitely delayed manned
Dragon etc etc.


You're confusing rockets with capsules. Manned Dragon and Orion don't
compete, since the purpose of one is LEO trips and that's only a
secondary mission for the other.


Dragon 2 has been designed to handle reentries from lunar missions.
Pretty much the same sort of reentry that Orion is designed to handle.
For now, SpaceX has canceled the commercial flight of people around the
moon (launched by Falcon Heavy), but I doubt it was due to any
deficiency in Dragon 2.

I don't see any fundamental reason Dragon 2 couldn't fulfill the crew
rotation role for Deep Space Gateway. I don't know about Boeing's
Starliner.


There are 'fundamental reasons' and then there are 'fundamental
reasons'. Dragon needs a much larger and more capable Service Module
if it's going to do that. Keep in mind that one of the big delays in
Orion is the late delivery of the European Service Module.




And if Dragon is to become real say by end of 2018, then continuing SLS
until end of 2018 isn't that big a deal in the grand schjeme of things
(where military spends 700 billion a year).


You're comparing apples (manned capsules) with aardvarks (launch
vehicles).


Currently the only manned missions planned for SLS/Orion are for Deep
Space Gateway.


There's a Mars orbital mission at the end of that pipeline.


Falcon Heavy/Dragon 2 could likely perform the same
missions.


Except it can't, for the same reason that SLS Block 1 can't. Falcon
Heavy is even shorter of cargo capacity than SLS Block 1 is.


Orion may be designed to be a one size fits all deep space
capsule, but its role on Deep Space Gateway is that of a crew taxi, just
like ISS. Deep Space Gateway will even have its own airlock module,
relieving Orion of the need to serve as one.


Actually my reading is that it's a bit more than that. It feels to me
like the Orion docking capability is how the pieces of the Gateway get
put together. And that brings us back to Dragon needing a more
capable Service Module and Falcon Heavy not having enough boost to do
the job.

Commercial launch vehicles are here and they're cheaper than ever.


Not manned ones. (not yet)


You're comparing apples (manned capsules) with aardvarks (launch
vehicles).


Then perhaps we should be comparing manned space transportation systems
to manned space transportation systems. Orion has no planned role
beyond manned taxi. The combination of Falcon Heavy/Dragon 2 looks like
it can do everything that SLS/Orion is required to do for Deep Space
Gateway.


Again, I think not. See above. Dragon doesn't have the life support
time to last for the early missions. Dragon/Falcon Heavy do not quite
have the capability to actually carry the pieces of the Gateway and
get them mated.



This is the classic spin-off argument. That's almost always bull$hit
too because the SLS program isn't doing much in the way of scientific
research,


No debate there. I was arguing that NASA direction should have been to
do massive R&D to develop new technooogies instead of being directed to
build a new rocket with technology choices imposed by politicians.


And just who picks the 'new technologies'?


NASA, as always. The aeronautical side is going to be flying a manned
low sonic boom demonstrator in upcoming years. It's the sort of thing
NASA has been doing for decades.


But they haven't been doing it in rocketry, where they have this
incestuous relationship with ULA. My suspicion is that NASA switching
to 'technology development' would just wind up being a subsidy to ULA
so that they wouldn't have to do it and 'outsiders' like SpaceX and
Blue Origin would get nothing useful to them.

But they'll still be dropping *all* of the SLS hardware in the ocean for
each and every flight. In a world where reusables are coming into their
own, that's just stupid.


At the time ARES/Orion were launched, it was decided expandable was
cheaper than re-usable. SpaceX proved that to be very wrong, but that
is only very recent.


Well, no, not so much.


Agreed. DC-X/XA was a very successful demonstrator. The fact that NASA
screwed the pooch on X-33 had everything to do with NASA picking the
worst of the three X-33 proposals and then mis-managing the program
until it finally died. Either of the other two proposals had a higher
chance of success. I'd have gone with the VTVL proposal since VTVL had
just been proven to be quite viable.

JF should note that DC-X/XA happened long before SpaceX was even an
idea, let alone a company.


Yeah. I was really disappointed when DCX didn't have a 'follow-on'
DCY.

For NASA, it is still better to have a bloody expensive SLS/Orion than
nothing (in case all other projects fail).


Except that NASA is more likely to fail (and cause others to fail by
expending preposterous amounts of money) than anyone else.


Agreed. SLS especially is an economic, technological, and programatic
disaster.


Orion isn't all that much better. It's had a lot longer to mature and
STILL is not ready.

I suspect that once commercial has manned programmes proven and running,
it will be the end of NASA trying to build rockets, and NASA's
involvement with rockets will be the same as it has for commercial
airplanes. Pure R&D.


I suspect you're wrong.


I think it will take both BFR and New Armstrong flying to finally kill
the pork laden monstrosity that is SLS. At least I hope so. We're not
going to need three heavy lifters and only one of those will be
completely expendable.


I wish I had your faith. I think there is so much money sunk in SLS
and it's so far along that it will continue until NASA decides to
develop yet another launch vehicle.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw