Author Topic: What place do solid rocket fuels have in spaceflight?  (Read 6982 times)

Offline BringBackSuperHeavies!

  • Member
  • Posts: 16
  • Australia
  • Liked: 3
  • Likes Given: 12
I donít understand. I can see why people use solid Rocket motors for kick stages, but for any other application I donít think they have a proper place in spaceflight. No need to add six strap on solid boosters, just make a decent size liquid fueled rocket to carry big payloads. Liqiud rockets have more payload for their size, and liquid rocket arenít actually that much more expensive to launch or add than solid rockets, if at all. You spend several million dollars on some low ISP solid booster. Maybe just add some more cheap liqiud engines and that can give you better performance for your money (bang for your buck). Plus, you can barely even throttle the things and you canít stop them until they run out of fuel. Use a comparably priced liquid engine that has deep throttle capabilities (actually not all liquid engines can stop then restart)! Solid rockets just provide a service that liquids can provide for a similiar or even less price.
« Last Edit: 09/23/2023 09:51 pm by zubenelgenubi »

Offline laszlo

  • Full Member
  • ****
  • Posts: 904
  • Liked: 1211
  • Likes Given: 514
I donít understand. I can see why people use solid Rocket motors for kick stages, but for any other application I donít think they have a proper place in spaceflight. No need to add six strap on solid boosters, just make a decent size liquid fueled rocket to carry big payloads. Liqiud rockets have more payload for their size, and liquid rocket arenít actually that much more expensive to launch or add than solid rockets, if at all. You spend several million dollars on some low ISP solid booster. Maybe just add some more cheap liqiud engines and that can give you better performance for your money (bang for your buck). Plus, you can barely even throttle the things and you canít stop them until they run out of fuel. Use a comparably priced liquid engine that has deep throttle capabilities (actually not all liquid engines can stop then restart)! Solid rockets just provide a service that liquids can provide for a similiar or even less price.

They're easier to design, build and maintain- no separate tanks and plumbing for fuel and oxidizer. No leaks. No pumps. No drive systems for pumps. Ignition is a well-known process that works without ullage,  pressurization or additional ignition fluids. Once loaded they can stay ready to use for extended (months, years) periods of time. Can be shipped cross-country fully loaded. No boil-off. No spills. Generally less sensitive to mechanical impact. Fueling not a part of the launch procedure so faster launch times. No need to maintain a tank farm and plumbing. No line of hundreds of trucks to refill the tank farm.

Higher energy density than many liquid stages, not just because of propellant density, but also because of the space between the pipes.

Combustion has been being stopped with enough precision to accurately deliver nuclear warheads since the early 1960's. Energy management techniques allow rockets to steer to specific velocity/position goals.

High ISP doesn't necessarily make sense in all situations, especially first stage boosters. Higher bulk thrust, which is easier to accomplish with solids than liquids, is sometimes more important.

Yes, liquid-fueled boosters have their advantages, but so do solids. Which to use depends entirely on what the specific requirements are.



Offline deltaV

  • Senior Member
  • *****
  • Posts: 2111
  • Change in velocity
  • Liked: 575
  • Likes Given: 1898
Virtually all military rockets and missiles use solids, for good reasons such as solids always being ready to use. I'm guessing the defense contractors that often design orbital rockets have often used the tools they're familiar with and used solids even for use cases where a purely civilian designer would have been more likely to choose liquids. Also some orbital rockets are actually repurposed ICBMs in whole or in part.

It seems that solids can't compete with liquids in the new world of partial or full re-usability so if you wait a decade or so solids for orbital launch will probably be a niche player at most. (Except for uncompetitive launch vehicles that are kept alive for national security or political reasons, e.g. Ariane 6, SLS.)
« Last Edit: 09/23/2023 05:37 pm by deltaV »

Offline laszlo

  • Full Member
  • ****
  • Posts: 904
  • Liked: 1211
  • Likes Given: 514
Virtually all military rockets and missiles use solids, for good reasons such as solids always being ready to use. I'm guessing the defense contractors that often design orbital rockets have often used the tools they're familiar with and used solids even for use cases where a purely civilian designer would have been more likely to choose liquids. Also some orbital rockets are actually repurposed ICBMs in whole or in part.

It seems that solids can't compete with liquids in the new world of partial or full re-usability so if you wait a decade or so solids for orbital launch will probably be a niche player at most. (Except for uncompetitive launch vehicles that are kept alive for national security or political reasons, e.g. Ariane 6, SLS.)

It isn't just because old dogs can't learn new tricks. Solids are a cost-effective, proven and reliable technology that allows an incremental increase in thrust for an existing booster without having to worry about a lot of esoteric engineering or complicated GSE.

Offline BringBackSuperHeavies!

  • Member
  • Posts: 16
  • Australia
  • Liked: 3
  • Likes Given: 12
Re: What place do solid rocket fuels have in spaceflight?
« Reply #4 on: 09/23/2023 10:59 pm »
So liquids arenít proven either? Not everyone uses solids. Not just SpaceX (you think Elon and his team didnít do a detailed analysis of the trade offs?) but Russia, and ULA themselves. Solids are technically more reliable, but when it comes to abort scenarios they present a problem. Since a solid cannot be throttled much, this also presents something of a problem when trying to precise control a rocketís ascent. And liquid engines are pretty darn reliable anyway. The SpaceX Merlin and some other have had very high success rates. As for bulk thrust, kerosene and or/methane can provide high bulk thrust while not compromising as much on efficiency. Also the core stage is liquid anyway, and thatís still less reliable and more complex. Likely the use of solids is mostly because big ICBM makers had control over rocket designs.

Offline Vahe231991

  • Full Member
  • ****
  • Posts: 1689
  • 11 Canyon Terrace
  • Liked: 462
  • Likes Given: 199
Re: What place do solid rocket fuels have in spaceflight?
« Reply #5 on: 09/23/2023 11:51 pm »
I donít understand. I can see why people use solid Rocket motors for kick stages, but for any other application I donít think they have a proper place in spaceflight. No need to add six strap on solid boosters, just make a decent size liquid fueled rocket to carry big payloads. Liqiud rockets have more payload for their size, and liquid rocket arenít actually that much more expensive to launch or add than solid rockets, if at all. You spend several million dollars on some low ISP solid booster. Maybe just add some more cheap liqiud engines and that can give you better performance for your money (bang for your buck). Plus, you can barely even throttle the things and you canít stop them until they run out of fuel. Use a comparably priced liquid engine that has deep throttle capabilities (actually not all liquid engines can stop then restart)! Solid rockets just provide a service that liquids can provide for a similiar or even less price.
Solid fuels remain an appropriate propellant for rockets capable of launching small payloads to orbit, namely if three or more stages are used. The Minotaur rocket family uses solid fuels because it is derived from the Peacekeeper and Minuteman ICBMs, both of which were designed to use solid fuel propellant.
« Last Edit: 09/29/2023 03:38 pm by Vahe231991 »

Offline laszlo

  • Full Member
  • ****
  • Posts: 904
  • Liked: 1211
  • Likes Given: 514
Re: What place do solid rocket fuels have in spaceflight?
« Reply #6 on: 09/24/2023 11:09 am »
So liquids arenít proven either? Not everyone uses solids. Not just SpaceX (you think Elon and his team didnít do a detailed analysis of the trade offs?) but Russia, and ULA themselves. Solids are technically more reliable, but when it comes to abort scenarios they present a problem. Since a solid cannot be throttled much, this also presents something of a problem when trying to precise control a rocketís ascent. And liquid engines are pretty darn reliable anyway. The SpaceX Merlin and some other have had very high success rates. As for bulk thrust, kerosene and or/methane can provide high bulk thrust while not compromising as much on efficiency. Also the core stage is liquid anyway, and thatís still less reliable and more complex. Likely the use of solids is mostly because big ICBM makers had control over rocket designs.

No one said that liquids aren't proven or reliable, just that the engineering and construction is simpler for solids. If you believe that the best part is no part, then no tanks, no plumbing, no pumps, no fueling or draining systems, no ullage, no pressurization (autogenous or otherwise), etc. has some appeal.

Of course SpaceX did the trade studies and it's perfectly reasonable that they decided not to go with solids. They're aiming for a spacecraft that can be refueled on Mars and flown back to Earth. The infrastructure to make solid boosters is too complex for off-planet use for now. On the other hand, for launch providers who just need to add a few tons of thrust to an existing first stage, especially low launch rate expendables, solids are a valid solution.

ISP/efficiency is not the only criterion for an engine. It's actually less important than energy density and high thrust for first stages. And yes, it's completely possible to build a liquid fuel high thrust booster, but it takes a lot more effort than for solids. For example, the Space Shuttle SRB contract  was let in 1973, work started in 1974, the first test was in 1977 and first orbital flight in 1981. Methalox Raptor development seems to have started around 2013 and 10 years on there is yet to be a successful orbital flight, even though SpaceX is a new-space fail early and often company with 21st century computer tech while Thiokol was using slide rule-based waterfall methodologies on a government contract. Don't get me wrong - this does not indicate anything wrong with SpaceX. It just shows how much more complicated getting that kind of thrust efficiently from reusable liquid engines is compared to solid boosters. That's the answer to your original question of what place do solid rocket fuels have in spaceflight. Solids are simple and cheap compared to liquids. if you can live with the solid's disadvantages and you don't need liquid's advantages, they have a place. Each booster design doesn't have to be perfect, just get the job done.

The reason that SLS uses SRBs is because the Shuttle did. SLS is supposed to keep old Shuttle workers employed and old Shuttle contractors in business. (I'm not getting into whether that's a good thing or not, it has nothing to do with liquid vs. solid.) The reason that Shuttle had SRBs is because Congress and Nixon did not want to fund a fully-reusable liquid-fueled first stage. Switching to solids was supposed to save the equivalent of nearly $15 billion in today's money in development costs. Plus, with the solids being fully reusable the operating cost was supposed to be low, too. ICBM's had nothing to do with the SLS choice of SRBs vs. liquid boosters.

So again, I'm not arguing that solids are always a better choice. I'm just answering your original question of what place do solid rocket fuels have in spaceflight.

Offline spacenut

  • Senior Member
  • *****
  • Posts: 5180
  • East Alabama
  • Liked: 2587
  • Likes Given: 2895
Re: What place do solid rocket fuels have in spaceflight?
« Reply #7 on: 09/24/2023 11:21 am »
In the future, I think solids will go away, especially with all the reusable rockets coming on line.  There might still be some strap on monolithic solids to help boost rockets.  However, large solids like SLS will go away, probably within the next 10 years.  To expensive to keep throwing away.  Reuse is the future.  I think liquids will get things to and from orbit, then SEP, NEP, nuclear, or other propulsion will eventually be used in space only, with liquid shuttle rockets to and from the surface of planets and moons. 

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15355
    • Space Launch Report
  • Liked: 8496
  • Likes Given: 1348
Re: What place do solid rocket fuels have in spaceflight?
« Reply #8 on: 09/25/2023 12:51 pm »
Solids are technically more reliable, but when it comes to abort scenarios they present a problem. Since a solid cannot be throttled much, this also presents something of a problem when trying to precise control a rocketís ascent.
In nearly 260 Falcon 9 flights there has only been one serious ascent abort (to orbit), and that was a Merlin 1C-powered vehicle.   Solids do have "throttle" profiles built into their grains.  Shuttle and Artemis SRBs thrust decreases for Max-Q, for example, and thrust decreases toward the end of their burns.  Meanwhile, there has been at least research into active throttling methods for solid motors.  There are long proven ways to precisely terminate solid thrust.
Quote
And liquid engines are pretty darn reliable anyway. The SpaceX Merlin and some other have had very high success rates.
Merlin 1D is the most reliable high thrust liquid rocket engine ever.  It is a very special machine and I don't see it as an argument for the norm.   Other liquid vehicles have more problems.  Electron just had a failed Stage 2 engine start.  Astra Rocket, Terran 1, LauncherOne, etc., all suffered failures just this year or last, and so, notably, did Super Heavy/Starship.  Raptor has not shown an inclination toward Merlin 1D reliablity.  SH has yet to even complete a static firing with all engines burning.

 - Ed Kyle
« Last Edit: 09/25/2023 01:02 pm by edkyle99 »

Offline Barley

  • Full Member
  • ****
  • Posts: 1002
  • Liked: 669
  • Likes Given: 366
Re: What place do solid rocket fuels have in spaceflight?
« Reply #9 on: 09/25/2023 02:54 pm »
Merlin 1D is the most reliable high thrust liquid rocket engine ever.  It is a very special machine and I don't see it as an argument for the norm.
When people get to choose the best becomes the norm.  There's a reason you're not driving a model T.

Merlin is the norm.  It sets the bar.  If an alternative is not in the ball park it will be at best a political boondoggle while almost all launches use Merlin.



Online DanClemmensen

  • Senior Member
  • *****
  • Posts: 5357
  • Earth (currently)
  • Liked: 4196
  • Likes Given: 1694
Re: What place do solid rocket fuels have in spaceflight?
« Reply #10 on: 09/25/2023 03:17 pm »
Merlin 1D is the most reliable high thrust liquid rocket engine ever.  It is a very special machine and I don't see it as an argument for the norm.
When people get to choose the best becomes the norm.  There's a reason you're not driving a model T.

Merlin is the norm.  It sets the bar.  If an alternative is not in the ball park it will be at best a political boondoggle while almost all launches use Merlin.
In 2023, approximately 90% of the world's payload mass launched to orbit uses the Merlin.

Offline Vahe231991

  • Full Member
  • ****
  • Posts: 1689
  • 11 Canyon Terrace
  • Liked: 462
  • Likes Given: 199
Re: What place do solid rocket fuels have in spaceflight?
« Reply #11 on: 09/25/2023 04:27 pm »
Which solid rocket booster in the 1990s was used to assist space launch vehicles in carrying the most payload mass into orbit?

Offline gin455res

  • Full Member
  • ****
  • Posts: 510
  • bristol, uk
  • Liked: 42
  • Likes Given: 72
Re: What place do solid rocket fuels have in spaceflight?
« Reply #12 on: 09/25/2023 10:52 pm »
I donít understand. I can see why people use solid Rocket motors for kick stages, but for any other application I donít think they have a proper place in spaceflight. No need to add six strap on solid boosters, just make a decent size liquid fueled rocket to carry big payloads. Liqiud rockets have more payload for their size, and liquid rocket arenít actually that much more expensive to launch or add than solid rockets, if at all. You spend several million dollars on some low ISP solid booster. Maybe just add some more cheap liqiud engines and that can give you better performance for your money (bang for your buck). Plus, you can barely even throttle the things and you canít stop them until they run out of fuel. Use a comparably priced liquid engine that has deep throttle capabilities (actually not all liquid engines can stop then restart)! Solid rockets just provide a service that liquids can provide for a similiar or even less price.


How about as a second-stage in a semi-reusable 3 stage launcher with reusable booster and upper stages?


Booster and upper stage are rtls. 

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15355
    • Space Launch Report
  • Liked: 8496
  • Likes Given: 1348
Re: What place do solid rocket fuels have in spaceflight?
« Reply #13 on: 09/26/2023 02:17 am »
Merlin 1D is the most reliable high thrust liquid rocket engine ever.  It is a very special machine and I don't see it as an argument for the norm.
When people get to choose the best becomes the norm.  There's a reason you're not driving a model T.

Merlin is the norm.  It sets the bar.  If an alternative is not in the ball park it will be at best a political boondoggle while almost all launches use Merlin.
Merlin 1D is an ideal, but it is not the norm.  It is an outlier.  There have been 16 orbital launch failures world-wide since the start of 2022.  Only two of those were, or likely were, due to solid rocket problems.

 - Ed Kyle
« Last Edit: 09/26/2023 02:20 am by edkyle99 »

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 39255
  • Minnesota
  • Liked: 25206
  • Likes Given: 12104
Re: What place do solid rocket fuels have in spaceflight?
« Reply #14 on: 09/26/2023 02:22 am »
It's an outlier, except most launches in the world use Merlin 1D. ???
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline StormtrooperJoe

  • Member
  • Posts: 66
  • Liked: 97
  • Likes Given: 15
Re: What place do solid rocket fuels have in spaceflight?
« Reply #15 on: 09/26/2023 02:31 am »
 I mean ICBMs are spacecraft, albeit only for for a very short period of time. Solid fuels are perfect for storeable ready to use rockets which means they will continue to be used in weaponry. There might be some sort of niche for satellites that can be launched at a moment's notice for the military, but even then as Firefly recently showed that's not necessarily needed.

Offline Proponent

  • Senior Member
  • *****
  • Posts: 7272
  • Liked: 2779
  • Likes Given: 1461
Re: What place do solid rocket fuels have in spaceflight?
« Reply #16 on: 09/26/2023 11:54 am »
There have been 16 orbital launch failures world-wide since the start of 2022.  Only two of those were, or likely were, due to solid rocket problems.

Out of how many stages and boosters (SRBs or LRBs) of each type in total?

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15355
    • Space Launch Report
  • Liked: 8496
  • Likes Given: 1348
Re: What place do solid rocket fuels have in spaceflight?
« Reply #17 on: 09/26/2023 12:43 pm »
There have been 16 orbital launch failures world-wide since the start of 2022.  Only two of those were, or likely were, due to solid rocket problems.
Out of how many stages and boosters (SRBs or LRBs) of each type in total?
That answer will take some work, as there are many vehicles with both liquid and solid elements.  In terms of LVs that consist of a solid "core" stage, I roughly count 40 launches during 2022-23 so far, with four failures - but two of those failures involved liquid propellant systems (RCS or kick stages)!

 - Ed Kyle
« Last Edit: 09/26/2023 07:38 pm by edkyle99 »

Offline Barley

  • Full Member
  • ****
  • Posts: 1002
  • Liked: 669
  • Likes Given: 366
Re: What place do solid rocket fuels have in spaceflight?
« Reply #18 on: 09/26/2023 03:41 pm »
There have been 16 orbital launch failures world-wide since the start of 2022.  Only two of those were, or likely were, due to solid rocket problems.
Out of how many stages and boosters (SRBs or LRBs) of each type in total?
That answer will take some work, as there are many vehicles with both liquid and solid elements.  In terms of LVs that consist of a solid "core" stage, I roughly could 40 launches during 2022-23 so far, with four failures - but two of those failures involved liquid propellant systems (RCS or kick stages)!

 - Ed Kyle

The answer is largely irrelevant.  It is only relevant if you make two incorrect assumptions.

There is a whole unreasonable expectation that prototypes should never fail.  How many prototypes you blow up is really only relevant if you have a program like Apollo where all launches were essentially prototypes.  A production run in low single digits is not a production run.

The lower cutoff for obvious incompetence. At what point do you stop counting amateurs that fail to get to orbit because they got the delta-V requirement wrong by orders of magnitude?  The Duffus to Einstein ratio is always disturbingly large and the cutoff is always arbitrary.

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15355
    • Space Launch Report
  • Liked: 8496
  • Likes Given: 1348
Re: What place do solid rocket fuels have in spaceflight?
« Reply #19 on: 09/26/2023 07:49 pm »
The lower cutoff for obvious incompetence. At what point do you stop counting amateurs that fail to get to orbit because they got the delta-V requirement wrong by orders of magnitude?  The Duffus to Einstein ratio is always disturbingly large and the cutoff is always arbitrary.
In terms of the solid motor failures during 2022-23, there aren't any beginners involved.  One was the 22nd Arianespace Vega (a Vega-C).  The other was (apparently, not yet confirmed a solid motor failure) the 10th Ceres-1, the first failure of the type.

Among liquids, yes there is a tilt toward new or relatively new entries.  The list includes ZQ-2 Y1, a Firefly Alpha, two Rocket 3.3 vehicles, two North Korean Chollima 1's, and the inaugural Terran 1 and RS-1 flights.  But the list also includes the 41st Electron, the sixth and final LauncherOne, and the surprising veteran upper stage failure on the inaugural JAXA H-3. 

In addition, the mostly solid SQX-1 and Epsilon rockets both suffered liquid RCS system leaks, Epsilon on its sixth flight and SQX-1 on its fourth.

 - Ed Kyle

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37435
  • Cape Canaveral Spaceport
  • Liked: 21437
  • Likes Given: 428
Re: What place do solid rocket fuels have in spaceflight?
« Reply #20 on: 09/29/2023 12:55 am »
Likely the use of solids is mostly because big ICBM makers had control over rocket designs.

nope, that is not the reason.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37435
  • Cape Canaveral Spaceport
  • Liked: 21437
  • Likes Given: 428
Re: What place do solid rocket fuels have in spaceflight?
« Reply #21 on: 09/29/2023 01:01 am »
, and the Delta III had nine strap-on solid fuel rocket boosters because the greater payload mass of the Delta III to LEO and GTO compared to that of the Delta II necessitated the provision for a large number of SRBs to provide enough initial thrust for the Delta III.

Stop posting misinformation.  Do research and composition without using AI.   
Delta I/II used 9 solids for more than 200 of its launches.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37435
  • Cape Canaveral Spaceport
  • Liked: 21437
  • Likes Given: 428
Re: What place do solid rocket fuels have in spaceflight?
« Reply #22 on: 09/29/2023 01:05 am »
I donít understand. I can see why people use solid Rocket motors for kick stages, but for any other application I donít think they have a proper place in spaceflight.

wrong, they have a place just as much as cold gas thrusters, hypergolic propellants, LH2, H202, etc have a place.

Offline Vahe231991

  • Full Member
  • ****
  • Posts: 1689
  • 11 Canyon Terrace
  • Liked: 462
  • Likes Given: 199
Re: What place do solid rocket fuels have in spaceflight?
« Reply #23 on: 09/29/2023 03:47 pm »
, and the Delta III had nine strap-on solid fuel rocket boosters because the greater payload mass of the Delta III to LEO and GTO compared to that of the Delta II necessitated the provision for a large number of SRBs to provide enough initial thrust for the Delta III.

Stop posting misinformation.  Do research and composition without using AI.   
Delta I/II used 9 solids for more than 200 of its launches.
What was rationale for various numbers of Castor solid-fuel boosters being used on numerous pre-Delta II variants of the Delta rocket, namely the Delta 0100, Delta 1000, Delta 2000, and Delta 3000, even though multiple Castor SRBs offered added thrust for the Delta 0100, Delta 1000, Delta 2000, Delta 3000, and Delta II upon liftoff?

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15355
    • Space Launch Report
  • Liked: 8496
  • Likes Given: 1348
Re: What place do solid rocket fuels have in spaceflight?
« Reply #24 on: 09/29/2023 05:58 pm »
What was rationale for various numbers of Castor solid-fuel boosters being used on numerous pre-Delta II variants of the Delta rocket, namely the Delta 0100, Delta 1000, Delta 2000, and Delta 3000, even though multiple Castor SRBs offered added thrust for the Delta 0100, Delta 1000, Delta 2000, Delta 3000, and Delta II upon liftoff?
The launchers were tailored to their missions.  Payload mass and orbit determined the number of solids.  Only three solids were used at first.  Six and nine-solid variants arrived later.  RCA paid for development of the more powerful Castor 4 solid in order to launch its Satcom series to GTO, creating the Delta 3914 variant.  Meanwhile, NASA was still flying relatively light NOAA satellites to sun synchronous orbits, requiring only a Delta 2310.  Etc.

 - Ed Kyle

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37435
  • Cape Canaveral Spaceport
  • Liked: 21437
  • Likes Given: 428
Re: What place do solid rocket fuels have in spaceflight?
« Reply #25 on: 10/02/2023 01:02 am »

What was rationale for various numbers of Castor solid-fuel boosters being used on numerous pre-Delta II variants of the Delta rocket, namely the Delta 0100, Delta 1000, Delta 2000, and Delta 3000, even though multiple Castor SRBs offered added thrust for the Delta 0100, Delta 1000, Delta 2000, Delta 3000, and Delta II upon liftoff?

STOP USING AI.  Your own post answers your question.

What was
The rationale for various numbers of Castor solid-fuel boosters being used on numerous pre-Delta II variants of the Delta rocket , namely the Delta 0100, Delta 1000, Delta 2000, and Delta 3000, even though multiple Castor SRBs offered   is added thrust.  for the Delta 0100, Delta 1000, Delta 2000, Delta 3000, and Delta II upon liftoff?
« Last Edit: 10/02/2023 01:05 am by Jim »

 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1