Is A Human Space Flight Compromise Emerging? (STS Extension/SD HLV etc)

[yg1968]

I am not convinced that the HLV needs to be human-rated. In other words, I would use commercial crew as space taxis as Augustine has suggested.

But never mind my question, I have answered it myself. If you have a domestic RD180 engine, you might as well use these engines to replace the boosters (as is suggested in this article).
http://www.spacedaily.com/news/rocketscience-04k.html

Oh - are you suggesting Atlas V CCBs to replace the SRBs while using SSME/RS-25e on the core as is being discussed on the "AJAX" thread (http://forum.nasaspaceflight.com/index.php?topic=22122.0)?
Or are you suggesting keeping the SRBs and converting the 8.4m core to kerolox and RD180?

As a political compromise, I was suggesting keeping the SRBs and converting the 8.4m core to kerolox with a domestic RD180. I am not an engineer. So I don't even know if what I am suggesting is even possible. I was trying to think of a way for a rocket to be somewhat Constellation derived but yet still fund a domestic RD-180.

But I guess that the plan in the other thread makes more sense as a political compromise. 

[sdsds]

I'm having a big problem with this Human Rated argument. There is a difference between Factor of Safety during design and demonstrated reliability.

Yes, and NASA has recently begun to acknowledge that there are multiple mechanisms by which a vehicle can be certified for crewed flight.  Demonstrated reliability can't be ignored!

The thing with EELV's is you don't have to pay for the infrastructure maintenance or development and you get plenty of free test launches.

Yes, and ULA continue to make this point because ... it's a good one!

What NASA needs to do is find ways that its involvement in EELV will be seen positively by the other big customer, USAF.  There are some EELV improvements USAF would want.  Can NASA involvement help with any of those?

I think the answer is, "Yes."  First, NASA could develop a payload for a Delta IV-Heavy mission, preferably with RS-68A.  USAF requires assured access to EELV-Heavy capability, but it costs quite a bit so the Heavy flight rate has been low.  Even just one NASA mission that imposed no onerous requirements (i.e. no crew) would help.

On a related note, NASA could help USAF by moving Atlas V closer to fielding a Heavy variant.  A NASA vehicle that used Atlas first stage boosters with the RD-180 throttled in the way they would need to be throttled on an Atlas V Heavy mission reduces risk associated with AV-H deployment.  There's been some discussion of an "AJAX" vehicle that would provide this benefit.

In summary:  NASA should strive to be a good partner to USAF in the EELV program, because those launch systems are currently under-utilized and under-developed.

[clongton]

I'm having a big problem with this Human Rated argument.

There's a *lot* more to human rating than just structurally designed to a 1.4 FoS. Human rating involves, at least for the engines, the ability to tell the flight avionics that it is about to experience a failure *before* it actually does so that the LAS can abort the crew spacecraft. The RS-68 does not have this capability. In addition there needs to be redundancy in all the valves and actuators so that if one doesn't function correctly the other one can be engaged to execute the valve's or actuator's function before an abort can be triggered. The RS-68 does not have this capability either. It was designed for cost, not safety. It was designed to function as is and if there's a problem the launch vehicle either blows up or goes in the drink; period. Human rating this engine involves a total redesign from the inside out. And that's just the engine. There's much more.

[alexw]

I'm having a big problem with this Human Rated argument.

There's a *lot* more to human rating than just structurally designed to a 1.4 FoS. Human rating involves, at least for the engines, the ability to tell the flight avionics that it is about to experience a failure *before* it actually does so that the LAS can abort the crew spacecraft. The RS-68 does not have this capability. In addition there needs to be redundancy in all the valves and actuators so that if one doesn't function correctly the other one can be engaged to execute the valve's or actuator's function before an abort can be triggered. The RS-68 does not have this capability either. It was designed for cost, not safety. It was designed to function as is and if there's a problem the launch vehicle either blows up or goes in the drink; period. Human rating this engine involves a total redesign from the inside out. And that's just the engine. There's much more.

   Chuck, FWIW, ULA's own paper "Atlas and Delta Capabilities to Launch Crew to Low Earth Orbit" (aka "Human Rating Atlas V and Delta IV"), paints a less dramatic picture. According to them, the emergency detection system is envisioned to be basically the same between Atlas V and Delta IV, the RS-68A upgrades don't sound that terrible (depending on whether the 1.4FS is insisted upon, or not), and the overall timespan is estimated to be 4.5 years (instead of 3.5 years for Atlas V, much of which seems to be the 4-year lead time for RS-68(A) from contract to delivery).

     "Human rating the Delta is a relatively modest activity, with the addition of an Emergency Detection System, an array of relatively small redundancy and safety upgrades, both in the vehicle and the engines that are almost trivial compared to the original development of the Delta IV."

Do you think that ULA has got it factually wrong here, or is painting a highly misleading picture?
   -Alex

[FinalFrontier]

You're right. We should stick to EELVs, because we know they work!

They aren't human rated. Bad argument.

I'm having a big problem with this Human Rated argument. There is a difference between Factor of Safety during design and demonstrated reliability. Let's say that ARES I was built to 1.4 and the Delta IV wasn't. Right now the Delta IV Core stage has had 19 successful flights. If there was only 2 test flights of ARES I I would still rather fly on a Delta IV.

The thing with EELV's is you don't have to pay for the infrastructure maintenance or development and you get plenty of free test launches. Any NASA owned rocket will never have enough money to launch often. Plus when the DOD decides to upgrade you get it for free.

Atlas V requires a simply sensor package addition. Thats it.

[FinalFrontier]

I am not convinced that the HLV needs to be human-rated. In other words, I would use commercial crew as space taxis as Augustine has suggested.

But never mind my question, I have answered it myself. If you have a domestic RD180 engine, you might as well use these engines to replace the boosters (as is suggested in this article).
http://www.spacedaily.com/news/rocketscience-04k.html

Oh - are you suggesting Atlas V CCBs to replace the SRBs while using SSME/RS-25e on the core as is being discussed on the "AJAX" thread (http://forum.nasaspaceflight.com/index.php?topic=22122.0)?
Or are you suggesting keeping the SRBs and converting the 8.4m core to kerolox and RD180?

As a political compromise, I was suggesting keeping the SRBs and converting the 8.4m core to kerolox with a domestic RD180. I am not an engineer. So I don't even know if what I am suggesting is even possible. I was trying to think of a way for a rocket to be somewhat Constellation derived but yet still fund a domestic RD-180.

But I guess that the plan in the other thread makes more sense as a political compromise. 

Would have to be RS84 not RD180. RD180 doesnt have needed thrust. Makes more sense to stick to the Hydrolox SDHLV core (cause we already got the parts) and exchange the boosters (see the AJAX thread).

[clongton]

I'm having a big problem with this Human Rated argument.

There's a *lot* more to human rating than just structurally designed to a 1.4 FoS. Human rating involves, at least for the engines, the ability to tell the flight avionics that it is about to experience a failure *before* it actually does so that the LAS can abort the crew spacecraft. The RS-68 does not have this capability. In addition there needs to be redundancy in all the valves and actuators so that if one doesn't function correctly the other one can be engaged to execute the valve's or actuator's function before an abort can be triggered. The RS-68 does not have this capability either. It was designed for cost, not safety. It was designed to function as is and if there's a problem the launch vehicle either blows up or goes in the drink; period. Human rating this engine involves a total redesign from the inside out. And that's just the engine. There's much more.

   Chuck, FWIW, ULA's own paper "Atlas and Delta Capabilities to Launch Crew to Low Earth Orbit" (aka "Human Rating Atlas V and Delta IV"), paints a less dramatic picture. According to them, the emergency detection system is envisioned to be basically the same between Atlas V and Delta IV, the RS-68A upgrades don't sound that terrible (depending on whether the 1.4FS is insisted upon, or not), and the overall timespan is estimated to be 4.5 years (instead of 3.5 years for Atlas V, much of which seems to be the 4-year lead time for RS-68(A) from contract to delivery).

     "Human rating the Delta is a relatively modest activity, with the addition of an Emergency Detection System, an array of relatively small redundancy and safety upgrades, both in the vehicle and the engines that are almost trivial compared to the original development of the Delta IV."

Do you think that ULA has got it factually wrong here, or is painting a highly misleading picture?
   -Alex

They are lumping the RD-180 (Atlas) and the RS-68 (Delta) conversationally together and speaking generically. Like all commercial concerns they paint the best picture they can, which is the RD-180, and let the reader make the leap themselves. It's called plausible deniability.

What I said about the RS-68 absolutely applies. The RS-68A is not human ratable without a major redesign. We (DIRECT) invested a *lot* of time and effort researching this very issue because we intended to do that engine development work and fly the Jupiter using the RS-68HR (DIRECT v2.0). But back then we actually had the time in the CxP schedule to do that and still beat Ares-I/V to the moon. So make no mistake – the RS-68A is not a human ratable engine. To make it so requires a major engine redesign effort from the inside out. Not much of the original engine configuration will remain. THAT is why the Air Force does not want to proceed with that and also why they have no problem human rating the RD-180, which requires only the addition of a sensor package to communicate with the flight avionics.

[alexw]

Do you think that ULA has got it factually wrong here, or is painting a highly misleading picture?

They are lumping the RD-180 (Atlas) and the RS-68 (Delta) conversationally together and speaking generically. Like all commercial concerns they paint the best picture they can, which is the RD-180, and let the reader make the leap themselves. It's called plausible deniability.

     Chuck, I'm looking at section "VII. Delta Human Rating" (page 9), which is specifically about Delta IV and RS-68(A). And the sentence I quoted above (in the third paragraph of the conclusion) is also specifically about Delta IV. What 'lumping'?

What I said about the RS-68 absolutely applies. The RS-68A is not human ratable without a major redesign. We (DIRECT) invested a *lot* of time and effort researching this very issue because we intended to do that engine development work and fly the Jupiter using the RS-68HR (DIRECT v2.0). But back then we actually had the time in the CxP schedule to do that and still beat Ares-I/V to the moon. So make no mistake – the RS-68A is not a human ratable engine. To make it so requires a major engine redesign effort from the inside out. Not much of the original engine configuration will remain.

    On page 9, under RS-68A upgrades, they mention: ECU Upgrade,  Startup H2 Mitigation (duct / start sequence), Added Potentiometer, and Pneumatic Valve Backup.  They go on to mention "Delta IV avionics and ordnance systems are already single fault tolerant, so a few modifications are required to patch single point failure “holes”", and "Pneumatics mechanical redundancy is also quite easy, with Atlas design approaches, and legacy hardware from Delta and Atlas existing. The booster hydraulics TVC system could require a more extensive redesign, which should be traded against the merits of retaining the flight proven mechanically non- redundant system."
    And, again, they conclude with: "Human rating the Delta is a relatively modest activity, with the addition of an Emergency Detection System, an array of relatively small redundancy and safety upgrades, both in the vehicle and the engines that are almost trivial compared to the original development of the Delta IV."

    Chuck, I hear what you're saying, but this paper is not giving the impression that RS-68 has to be practically thrown away and done over again. Do you believe that the ULA document is factually wrong?
   -Alex