Jeff Findley wrote on Tue, 17 Apr 2018
19:59:06 -0400:

In article ,
says...

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.


Yes, working with NASA is a p.i.t.a. That service module is based off
the ESA ATV, which is flight proven. But NASA required a lot of changes
to make it "better". Unfortunately, "better" is the enemy of "good
enough".


So you want to blame NASA because ESA couldn't hit their schedule?
That's a bit of a stretch.


Considering the schedule for SLS/Orion, I'd think SpaceX could make
whatever modifications are necessary to make it work and it would still
be far cheaper than SLS/Orion.


Perhaps, but SpaceX would have to develop an actual Service Module
instead of a trunk. They need to at least triple the life support
capacity of the Dragon V2 and get a read engine and fuel on that
Service Module so they can actually do a TLI burn, pick up the piece
of the Gateway, and rendezvous and dock with the Gateway so they can
get it assembled. All that adds enough weight that it's probably at
(if not over) the edge of what Falcon Heavy can do.


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.

I've not seen that. It must be many, many years out.


Original schedule put it out in 2033 or so, but that was all
predicated on the completion of the Lunar Gateway. Since the Upper
Stage has slid, it's now probably out near 2040.


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.

I call b.s. The Deep Space Gateway missions all "co-manifest" a module
for DSG with an Orion. Split that into two, or more, Falcon Heavy
launches.


There's a reason they do that. Handwavium doesn't make that reason go
away. You'd have to do the rendezvous of the pieces at the Moon
because you don't have the grunt to do it in LEO and then go to the
Moon like what was done for Apollo. That means every load essentially
needs a 'service module' to get it into Lunar orbit and to rendezvous.
Yes, you can break the thing into 12,000,000 discrete parts and launch
them all separately, but it's hardly practical.


EOR was a thing long before LOR took over because it was seen as the way
to get to the moon faster in order to beat the "godless commies" to the
moon. There is zero reason we can't do EOR today with Falcon Heavy.


See above.


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.


So give it a more capable service module. Or, heaven forbid, launch
Orion on Falcon Heavy and a DSG module on another Falcon Heavy.


I don't think Falcon Heavy has enough grunt to get an Orion to TLI.
It's dubious if it has enough grunt to get a Dragon V2 with a
sufficiently capable Service Module to TLI.

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.


My biggest beef is with SLS. So launch Orion on Falcon Heavy. It's
already flown (a boilerplate) on Delta IV Heavy so the b.s. that only
SLS can launch it is quite strong smelling.


You can launch it but you can't get it to the Moon.

Start out looking at the masses. Orion plus Service Module is a
little over 26 tonnes at launch. That's a bit more than Falcon Heavy
can send to TLI. There are a couple of choices there. Orion carries
more fuel than it needs, so perhaps you could get within the TLI
capability of Falcon Heavy by dropping a few tonnes of fuel. More
likely, though, they're going to want to keep that as safety margin,
which brings us to the other possibility. Falcon Super Heavy.

Falcon Heavy can get Dragon V2 to TLI, but without an engine and
service module you don't have a way to actually burn into lunar orbit
or any stay time. The Super Dracos on Dragon V2 have more than enough
thrust, but not nearly enough fuel. You could probably get by with a
lighter Service Module on Dragon V2 and do something like use the
Service Module engine for insertion and rendezvous and the Super
Dracos for the return burn to Earth. That probably gets a Dragon V2
just inside Falcon Super Heavy capability. But if you launch Gateway
pieces on separate launches, you're going to need to do a lot more
maneuvering in lunar orbit, so that makes the Service Module heavier.

Then there's life support. Orion has 122+ man days of life support.
Dragon V2 has less than 50 man days of life support. The assembly
missions for the Lunar Gateway pretty much max out the Orion life
support capability, so Dragon V2 needs to nearly triple its current
capability.



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.


ULA isn't going to last much longer unless Vulcan/ACES comes very
quickly, is super cheap, and can do more than BFR and New Armstrong. I
personally think ULA is a "dead man walking". I doubt that NASA funding
technology demonstrators would keep them alive, unless those led to
something really groundbreaking. Possibly ACES derived fuel depots, but
ULA's Vulcan would be too expensive to fuel the thing in an affordable
way. Another possibility is an ACES derived lunar lander.


I think NASA and USAF will keep ULA running just fine. I think that's
a shame, but there you are.


But commercially? ULA's got nothing in the pipeline to keep it
financially viable in the commercial launch industry.


And yet they still get launches.

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.

Agreed. NASA ate that seed corn.


DCX showed so much promise. That's one I DO think NASA let die
because of Shuttle and ULA expendables.

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.

Agreed. Which is why I'd rather see NASA do commercial contracts for
HLV, "deep space" capsules, lunar landers, and etc. Every single one
with two or more providers.


They'll try to make the argument that that is too high risk and doing
two of everything is just too expensive. I think that's a hard case
for them to make, given history, so I generally agree with you. I'd
rather see them provide a list of requirements and then see what
people offer to build and what each costs. Perhaps do an internal
estimate of it done 'in house', as well. If nobody comes in low
enough, you don't do it. It makes NASA compete with commercial
vendors. You'd need an independent review team to review the
proposals and you'd need some way to enforce cost estimates.

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.

Sunk cost fallacy is strong with the Congresscritters. But eventually
reality will set in. 10x the cost with 1/10th the flight rate will
hopefully become obvious after a few years of BFR and New Armstrong
flying. Reusable launch vehicles are the wave of the future. It might
take 10 years or so, but with stubborn people like Musk and Bezos
leading the way, we'll eventually get there.


I wish I was that optimistic.


--
"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