A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Policy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Senate Launch System continues to delay development



 
 
Thread Tools Display Modes
  #1  
Old August 2nd 19, 12:42 AM posted to sci.space.policy
Greg \(Strider\) Moore
external usenet poster
 
Posts: 752
Default Senate Launch System continues to delay development

https://arstechnica.com/science/2019...ellant-depots/

Basically, NASA is so invested in SLS they apparently don't want to develop
other tech.

I love the part about how Falcon 9 Heavy is mythical (at the time) while SLS
isn't...


  #2  
Old August 2nd 19, 01:30 AM posted to sci.space.policy
Alain Fournier[_3_]
external usenet poster
 
Posts: 548
Default Senate Launch System continues to delay development

On Aug/1/2019 Ã* 19:42, Greg (Strider) Moore wrote :
https://arstechnica.com/science/2019...ellant-depots/


Basically, NASA is so invested in SLS they apparently don't want to
develop other tech.

I love the part about how Falcon 9 Heavy is mythical (at the time) while
SLS isn't...


SLS isn't mythical. It is very real. It's a real boondoggle.


Alain Fournier
  #3  
Old August 2nd 19, 12:48 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Senate Launch System continues to delay development

In article ,
says...

https://arstechnica.com/science/2019...ellant-depots/

Basically, NASA is so invested in SLS they apparently don't want to develop
other tech.


Actually this isn't news about what is happening today. It is news
about what happened years ago when ULA published papers about propellant
depots and how they could develop that technology starting with flying
experiments on Centaur upper stages. This dovetailed nicely with all
their papers about ACES upper stages (reusable, so they would need to be
refueled).

Boeing was furious, at the time, and tried to get ULA's chief scientist
fired! But ULA's CEO, at the time (I don't believe it was Tory Bruno
back then) went to bat for him and he didn't lose his job. But he was
told to never talk about depots again!


Today, NASA signed an agreement with SpaceX to develop in space
refueling technology (presumably for Starship). That conversation on
Twitter is what spurred ULA's former chief scientist to Tweet about the
above.

I love the part about how Falcon 9 Heavy is mythical (at the time) while SLS
isn't...


Yeah, that was always disingenuous considering how much commonality
there is between the (then flying) Falcon 9 and the (then under
development) Falcon Heavy. SLS, by comparison, is pretty much all new
except for the SSMEs they took off of all of the orbiters that are in
museums.

Oh, and Ars Technica, and Eric Berger in particular, publish great
articles about "space". I like their online forums as well.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #5  
Old August 3rd 19, 05:58 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Senate Launch System continues to delay development

In article ,
says...

On 2019-08-02 07:48, Jeff Findley wrote:

Yeah, that was always disingenuous considering how much commonality
there is between the (then flying) Falcon 9 and the (then under
development) Falcon Heavy. SLS, by comparison, is pretty much all new
except for the SSMEs they took off of all of the orbiters that are in
museums.



Aren't the SRBs also derived from Shuttle ones?


They reuse the steel casings, but that's about it.

Or are they sufficiently
different in terms of the compound and the shape of it inside the
cylinders that they could be considered totally different?


They are essentially a completely new design. Different size (5
segments instead of 4), different propellant mixture, different
insulation, zero recovery hardware, and etc. In the first full scale
ground test of the 5 segment SRB, the nozzle literally blew to huge
pieces near the end of the burn (search for it on YouTube). If it were
so easy to make a 5 segment SRB, that nozzle wouldn't have fragged.
They also had problems with the new insulation in the design. These
things really aren't as easy as they seem.

So no, the shuttle SRBs are quite different and didn't really help
Northrup Grumman Innovation Systems (formerly Orbital ATK) create an SRB
that worked right the first time on the test stand.

Considering SLS uses conventional already developped tech, are there
really technical reasons why this thing can't fly yet? I get the
impression that this pork programmed is designed to last as long as they
possibly can to maintain jobs as long as tghey possibly can, so delays
benefit politicians.

They have tested the SSMes many times aready. Any indication that there
are problems with them with their new controllers? or are they ready for
flight and NASA just keeps testing them as a token "deliverable" to show
Congress ?




--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #6  
Old August 3rd 19, 06:05 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Senate Launch System continues to delay development

In article ,
says...
Considering SLS uses conventional already developped tech, are there
really technical reasons why this thing can't fly yet? I get the
impression that this pork programmed is designed to last as long as they
possibly can to maintain jobs as long as tghey possibly can, so delays
benefit politicians.

They have tested the SSMes many times aready. Any indication that there
are problems with them with their new controllers? or are they ready for
flight and NASA just keeps testing them as a token "deliverable" to show
Congress ?



Forgot to reply to the above (from JF).

Part of it is Boeing's incompetence due to the cost plus nature of the
contract. Part of it is that it's not really shuttle derived. Like I
said, the only things being reused are the SSMEs and those got new
engine controllers and are being used in expendable mode at a higher
thrust setting than they were used on shuttle missions.

All of the shuttle ET tooling was destroyed. The SLS core stage is
being built with all new tooling. And as I said in the last post, the 5
segment SRBs are really a new design that only shares the steel casings
with the shuttle's four segment SRB design. Everything else has been
redesigned for the larger size of the booster.

The Delta IV derived upper stage is the most ready to fly. After that,
the SSMEs are the most ready to fly out of the entire design, IMHO. I
don't think the SRB has been test fired again after the test that blew
the nozzle into chunks. The core stage has not been test fired yet.
That's the "Green Run" that's been talked about a lot in the space news
press.

Jeff

--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #7  
Old August 4th 19, 03:29 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Senate Launch System continues to delay development

In article ,
says...

On 2019-08-03 12:58, Jeff Findley wrote:

They are essentially a completely new design. Different size (5
segments instead of 4), different propellant mixture, different
insulation, zero recovery hardware, and etc. In the first full scale
ground test of the 5 segment SRB, the nozzle literally blew to huge
pieces



Thanks for the reality check. I had been aware only of vibration issues
dating bac from Ares.

Wouldn't having 3 o4 4 smaller SRBs have yielded fewer challenges in
terms of scaling them up while keeping roughly same thrust?


Doubtful. They wanted to stay with, roughly, the same structural layout
for connecting the SRBs to the tank. One big beam through the intertank
area (at the top of the SRBs) to transfer the thrust and help with
vibrations.

Are the SRBs what is currently holding back SLS? what other problems are
causing delays?


Not at all. The SRBs are lagging, but not as much as the rest of the
thing.

The long pole in the tent has always been the core stage being built by
Boeing. The Exploration Upper Stage, also being designed by Boeing, has
been placed on hold and rumor has it that NASA may try to cancel the
failing EUS contract and open it up for a competitive bid. The EUS is
needed for Block 1B and Block 2.

The interim upper stage of Block 1A is a slightly modified Delta IV
upper stage. It's undersized for SLS (hence the lower payload of Block
1A), but it's obviously "ready to fly" since it works just fine on Delta
IV.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #8  
Old August 4th 19, 03:35 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Senate Launch System continues to delay development

In article ,
says...

On 2019-08-03 13:05, Jeff Findley wrote:

said, the only things being reused are the SSMEs and those got new
engine controllers and are being used in expendable mode at a higher
thrust setting than they were used on shuttle missions.


Considering the number of times NASA has bragged about SSMEs engine
tests, are they really "expendanble" since they seem to be test fired
many times over the last few years?


They're being used on SLS in an expendable mode. That's a fact. The
RS-25E engines that will be "new builds" will almost certainly be test
fired before being used *once* on SLS in an expendable mode. No doubt
some tweaks to the design were made with that in mind.

All of the shuttle ET tooling was destroyed.


If there had been no political interference, when Constallation was
replaced with SLS, would the core still have been ET-like and sent to
Michoud for construction? aka: is the concept/design sound or did they
impose an ET-like design to help Michoud?


The destruction of the ET tooling dates back to the Ares I/Ares V days.
So if you want to blame someone, blame than NASA Administrator Mike
Griffin for that.

Without tooling and work for some time, I take it Michoud had to start
from scratch when it got contract for SLS main tank?


Pretty much. They bragged a lot about the new tooling and (new to
Michoud) friction stir welding, which they had a *lot* of problems with.

the nozzle into chunks. The core stage has not been test fired yet.


Physically, can they test fire the core stage standing up without 2
boosters attached?


Yes. That's the whole point of the "Green Run" tests. NASA did the
same with the Saturn V's first stage. This whole SLS program is being
run in a back to the 60s and 70s way, IMHO. Lots of tests at lots of
different sites, making sure the pork is spread around.

July 25, 2019
?Green Run? Test Will Pave the Way for Successful NASA Moon Missions
https://www.nasa.gov/exploration/sys...est-paves-way-
for-nasa-moon-missions.html

Jeff

--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
NASA Seeks Space Launch System Advanced Development Solutions Alan Erskine[_3_] Policy 10 March 28th 12 07:11 AM
The SLS (Senate Launch System) Hop Policy 0 March 19th 11 06:44 PM
Possible Shuttle launch delay Pat Flannery Policy 0 March 14th 10 03:50 PM
launch delay 24 hrs Jim Oberg Space Shuttle 4 August 6th 07 03:03 AM
Shapiro Delay and the Solar System Galactic Motion GSS Astronomy Misc 38 February 17th 07 08:11 PM


All times are GMT +1. The time now is 12:20 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.