Why did RP-1/H2O2 engines never took off?

[fredinno]

4 hours ago, wumpus said:

The linked article quotes a CASTOR 120 as being sold for  $17.5 million bucks for one (of four stages) and a ~1 ton payload.  Also both  rockets the linked article mentions (Orbiting carbon observatory and Glory) failed.  The H-IIA (based on the CASTOR) seems to be doing well, but I can't tell if it is manufactured by ATK(/Orbital) or Mitsubishi (the booster specific wiki is in Japanese).  (Vacuum) ISP is 280, but success is limited (note that one of the launches, the Glory IRC, failed due to rocket assembly issues and wasn't motor specific).

These really don't resemble KSP (cheap and inefficient) SRBs at all.

No, H-IIA SRBs are made by IHI Aerospace.

Quote

In 2006 Orbital Sciences Corporation agreed to pay $17.5 million for the Castor 120 motors used in the Taurus XL launch vehicles for the Orbiting Carbon Observatory and Glory satellites...

...which implies 2 for $17.5 million, or $8.75 million. Also, production rates are pretty low- though Castor 120 and 30 are also used for Athena, which was SUPPOSEDLY going to be revived by 2012. Any minute now....

 

Also, ATK makes CASTOR 30, which is a lot more successful in comparison, with no failures so far. ATK also proposed a Solid booster replacement for the RD-180 (which could also be used for Antares) http://www.americaspace.com/?p=68279

Also, ATK makes the STAR upper stage family of motors, and the Shuttle and Dark Knight Adavanced SLS SRBs.

 

[DBowman]

On 1/14/2016 at 7:31 AM, RuBisCO said:

Well that depends on what is used as inhibitors, but using Soyuz as a standard, it is claimed that its 6 months stand-by endurance is limited by decomposition of its H2O2 thruster for attitude control of the re-entry capsule. So as a OMS, H2O2 works fine as long as your not planning on staying up there for more than 6 months.

Also I learned that Soyuz main engine turbos are H2O2 driven.

Is there any way to 'stretch' it's longevity? or some simple way to manufacture H2O2 that you could use as a 'plug-in' to extend Soyuz useful life?

Edited January 16, 2016 by DBowman

[Kryten]

19 hours ago, fredinno said:

Well, it should be fine for most LEO applications- just makes it impossible to use as a CRV or emergency return vehicle of some sort. The Shuttle did fine with a much more limited lifespan.

That's not 'fine for most LEO applications', that's 'fine for a subset of crewed LEO applications'; a tiny niche. Even X-37 stays up too long for it to be a practical combination.

[fredinno]

4 hours ago, DBowman said:

Also I learned that Soyuz main engine turbos are H2O2 driven.

Is there any way to 'stretch' it's longevity? or some simple way to manufacture H2O2 that you could use as a 'plug-in' to extend Soyuz useful life?

Maybe a small reactor to turn H2O and O2 produced from H2O2 decay back into H2O2?

[GoSlash27]

 Well...

 As a civilian booster, a hypergolic engine's advantage is nil. All that's eliminated is an on board igniter, which isn't necessary. That ignition system is miniscule as far as overall cost, mass, and complexity.

Plus there's an added safety hazard of accidental ignition from leaks (and corrosion, which makes leaks more likely).

 Hypergolics really aren't worth the aggravation for an engine that only needs to be lit once.

Best,

-Slashy

[fredinno]

8 hours ago, GoSlash27 said:

 Well...

 As a civilian booster, a hypergolic engine's advantage is nil. All that's eliminated is an on board igniter, which isn't necessary. That ignition system is miniscule as far as overall cost, mass, and complexity.

Plus there's an added safety hazard of accidental ignition from leaks (and corrosion, which makes leaks more likely).

 Hypergolics really aren't worth the aggravation for an engine that only needs to be lit once.

Best,

-Slashy

That's why I proposed RP-1 H2O2, which is not toxic.

[DBowman]

On 1/16/2016 at 4:13 PM, fredinno said:

Maybe a small reactor to turn H2O and O2 produced from H2O2 decay back into H2O2?

aww - I was hoping for a model number ...