Author Topic: Ares I 1st stage replacement  (Read 125076 times)

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 12805
    • Space Launch Report
  • Liked: 3770
  • Likes Given: 740
Re: Ares I 1st stage replacement
« Reply #400 on: 12/01/2008 06:02 PM »
If you want my untrained opinion, I don't think that Ares-I looks particularly safe.  It is something to do with the lower stage being narrower than the upper stage.

If launch vehicle development depended on "looks", the space shuttle would never have been developed. 

The SRB is stronger and much heavier than the wider, lighter upper stage.  A flared transition is not the most efficient structure, but there is no reason it can't be made sufficiently rigid to do its job.

 - Ed Kyle
« Last Edit: 12/01/2008 06:02 PM by edkyle99 »

Offline guru

  • Full Member
  • ****
  • Posts: 483
  • Liked: 73
  • Likes Given: 33
Re: Ares I 1st stage replacement
« Reply #401 on: 12/01/2008 06:05 PM »
Guru, no offence was intended in my reply.  I was simply responding to your post by trying to offer additional points in favour of the scheme.  I certainly wasn't being critical of your thoughts in any way; I was just offering some observations.

Oh, none taken at all.  I was just clumsily trying to explain my earlier statements so that you would also know that I meant no offense.

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 7126
  • A spaceflight fan
  • London, UK
  • Liked: 646
  • Likes Given: 759
Re: Ares I 1st stage replacement
« Reply #402 on: 12/01/2008 06:19 PM »
If launch vehicle development depended on "looks", the space shuttle would never have been developed. 

I don't think that it should have, at least not in the configuration we have today.  However, that is completely off-topic so I won't go there. 

What I will say is that I would expect that the "narrower as you get lower" shape of the Ares-I probably imparts some drag penalties.
« Last Edit: 12/01/2008 06:20 PM by Ben the Space Brit »
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline Capt. Nemo

  • Member
  • Full Member
  • *
  • Posts: 143
  • USS Nautilus
  • New Jersey
  • Liked: 0
  • Likes Given: 0
Re: Ares I 1st stage replacement
« Reply #403 on: 12/15/2008 04:08 AM »
Question - Is it possible to make a Solid Rocket first stage for the Ares 1 that would be the same diameter or larger than the upper stage?

Assumed Answer - Yes, but it would be a whole different animal from the SRB that they have now. Along with other problems....

Comments?
"You can't declare yourself the boss of a chicken farm when you've only got one egg."  - Chinese saying

Offline Jorge

  • Senior Member
  • *****
  • Posts: 6180
  • Liked: 32
  • Likes Given: 0
Re: Ares I 1st stage replacement
« Reply #404 on: 12/15/2008 04:37 AM »
Question - Is it possible to make a Solid Rocket first stage for the Ares 1 that would be the same diameter or larger than the upper stage?

Yes, it is possible, in the loose sense that it doesn't violate the laws of physics.

The laws of economics and common sense, on the other hand...

Quote
Assumed Answer - Yes, but it would be a whole different animal from the SRB that they have now. Along with other problems....

Comments?

It would completely destroy the original rationale for an SRB-based first stage. That rationale is already in tatters; this would be the final straw.

It would no longer be rail-transportable and therefore would likely require a new factory.

It would likely strain the capacity of the VAB cranes.

It would definitely be ruinously expensive. It would make the current SRB look downright cheap.
JRF

Offline Khadgars

  • Full Member
  • ****
  • Posts: 1005
  • Long Beach, California
  • Liked: 203
  • Likes Given: 590
Re: Ares I 1st stage replacement
« Reply #405 on: 12/15/2008 08:58 AM »

*sighs* SO... do it the way they did on Saturn I-- the FIRST TIME J-2 was in development and not ready when the vehicle was-- develop an interim stage powered by RL-10's to do the job til the J-2 powered variant is ready... 
The S-IV stage was not "interim".  It was designed and developed to be an operational stage.  It would have flown on several Saturn variants (C-1, C-2, C-3, etc.).  It was bypassed by events when JFK decided to go to the Moon in a hurry.

Quote
That's why I get SO frustrated with all of this that I just disappear for days-- here we are 50 years later, with all the knowledge and technology and capabilities we have as the fruits of the labors done then, and less is possible NOW than was possible 50 years ago!  And yeah I know 'money was no object' and all of that, but if we haven't learned how to do something cheaper or better or faster in 50 years we just need to hang it up and call it a day... IMHO!  OL JR :) 

The glass is more than half full! 

The U.S. and Europe are operating robots on and around Mars.  Fifty years ago many maps of Mars still showed "canals".  Cassini is at Saturn.  Messenger is bound for Mercury.  New Horizons is Pluto-bound.  The U.S. and its international partners are operating a crewed space station in orbit - and have been for a decade now.  Fifty years ago such things were science fiction fantasy. 

The U.S. launch fleet now consists of multiple ELVs and Shuttle.  A brand new human launch system is being developed and at least two substantial commercial efforts are underway to develop two more launch vehicles and two more orbiting spacecraft to fly on them. 

In 1958, the U.S. "launch fleet"' consisted of Vanguard, Redstone/(Juno I), Jupiter(Juno 2), and Thor-Able.  One Atlas missile had been orbited as a stunt, with very little payload.  The most powerful of these could put about 50 kg into low Earth orbit - at enormous cost and with very low reliability.  No astronauts had yet flown.  Project Apollo, as we now know it, was still three years in the future.

 - Ed Kyle     

qft ;)

Offline Capt. Nemo

  • Member
  • Full Member
  • *
  • Posts: 143
  • USS Nautilus
  • New Jersey
  • Liked: 0
  • Likes Given: 0
Re: Ares I 1st stage replacement
« Reply #406 on: 12/21/2008 03:54 AM »
If the discussion is about kerosene engines for this hypothetical 1st stage replacement, then why not throw the RS-84 into the mix for contention? I know that it's development never got beyond the paper stage but they were planning on it having 1,000,000 pds. [email protected] sea level. (according to www.astronautix.com)  Stick four of those babies on the bottom of a first stage, and there ya go.   ;D
You would only need two engines like this.  See the first three or four pages of this thread for examples.  We called it "Ares IB". ;)
 - Ed Kyle

Ed, I did look back and saw that design. According to what figures I have (or I should say, Mark Wade has) the RS-68 has  less power than the RS-84. Using figures from his web site I figured -

RS-68 - 650,000 [email protected] 
* 2 =    1,300,000  " " " "
* 4 =    2,600,000 " " " " 

RS-84 - 1,000,000 [email protected]
*2  =     2,000,000 " " " "
*4  =     4,000,000 " " " "

5 Segment RSRM - 3,500,000 pds.thrust @S.L.

Now granted, the RS-84 hasn't been built yet. But my reasoning was that you would have to have as much or more thrust for a replacement than the RSRM provides in order for it to be acceptable.
     I'm only an amateur playing around on the computer though, so I know I've probably missed something. ( or a few somethings  :D ).
« Last Edit: 12/23/2008 05:22 AM by Capt. Nemo »
"You can't declare yourself the boss of a chicken farm when you've only got one egg."  - Chinese saying

Offline tnphysics

  • Regular
  • Full Member
  • ****
  • Posts: 1073
  • Liked: 0
  • Likes Given: 0
Re: Ares I 1st stage replacement
« Reply #407 on: 01/02/2009 12:54 AM »
Actually, you could use somewhat less thrust, as the Isp is higher.  Don't know how much less, though.

Offline luke strawwalker

  • Regular
  • Full Member
  • ****
  • Posts: 1032
  • Liked: 3
  • Likes Given: 0
Re: Ares I 1st stage replacment.
« Reply #408 on: 03/23/2010 11:57 PM »
If you're going to imagine a launch vehicle for the Orion based on Delta IV, then how about a D-IV core booster with 2 4 segment RSRM's and a J-2S upper stage? (something that looks similar to what the Titan looked like) The solids would give more than enough thrust to get a 25mT Orion into Orbit, wouldn't it? The J-2S development would probably be cheaper than J-2X which is basically a whole new engine.

(Unrelated question - Does anyone here know if the solid rockets used for ICBM's are segmented? I ask because they are, as far as i know, extremely reliable LV's.)

AFAIK there are NO segmented ICBM motors... they are typically spiral filament wound casings with a monolithic grain. 

The speed and lift requirements are substantially lower for ICBM's than orbital vehicles...

OL JR :)
NO plan IS the plan...

"His plan had no goals, no timeline, and no budgetary guidelines. Just maybe's, pretty speeches, and smokescreens."

Tags: