Quote from: envy887 on 01/02/2018 07:14 pmQuote from: edkyle99 on 01/02/2018 07:07 pmQuote from: envy887 on 01/02/2018 06:59 pmI think you're right. Although, that ACES has 68 t of hydrolox and 4x RL-10. If Centaur 5 has ~50 t and 2x RL-10 it will get more like 6.5 t to GTO without SRBs and about 13 t to GTO with 6x GEM-63XL, which would be enough to hit all the EELV reference payloads and orbits by my calcs.To meet the EELV requirements list, Vulcan needs to lift 8.165 t to a GTO that is about 1,800 m/s short of GEO or 6.577 tonnes to GEO. Those are the goals that I suspect Vulcan Centaur 5 is being designed to meet. - Ed Kyle6+ t to GEO is by far the harder of those two requirements, and the Vulcan core with a 50 t dual RL-10 upper stage and six GEM-63XL can most likely do it with plenty of margin. They will need the SRBs, but that's no issue for NSS launches.They can bring ACES in later and drop most (for GEO) or all (for GTO) of the SRBs for the same performance.Keep in mind that ULA considers the RL-10C series LRE's as the Vulcan Baseline for Centaur-5 and ACES. Keep in mind that they have not announced what will power these stages so really math needs to be done for not just RL-10 but also the LRE options.
Quote from: edkyle99 on 01/02/2018 07:07 pmQuote from: envy887 on 01/02/2018 06:59 pmI think you're right. Although, that ACES has 68 t of hydrolox and 4x RL-10. If Centaur 5 has ~50 t and 2x RL-10 it will get more like 6.5 t to GTO without SRBs and about 13 t to GTO with 6x GEM-63XL, which would be enough to hit all the EELV reference payloads and orbits by my calcs.To meet the EELV requirements list, Vulcan needs to lift 8.165 t to a GTO that is about 1,800 m/s short of GEO or 6.577 tonnes to GEO. Those are the goals that I suspect Vulcan Centaur 5 is being designed to meet. - Ed Kyle6+ t to GEO is by far the harder of those two requirements, and the Vulcan core with a 50 t dual RL-10 upper stage and six GEM-63XL can most likely do it with plenty of margin. They will need the SRBs, but that's no issue for NSS launches.They can bring ACES in later and drop most (for GEO) or all (for GTO) of the SRBs for the same performance.
Quote from: envy887 on 01/02/2018 06:59 pmI think you're right. Although, that ACES has 68 t of hydrolox and 4x RL-10. If Centaur 5 has ~50 t and 2x RL-10 it will get more like 6.5 t to GTO without SRBs and about 13 t to GTO with 6x GEM-63XL, which would be enough to hit all the EELV reference payloads and orbits by my calcs.To meet the EELV requirements list, Vulcan needs to lift 8.165 t to a GTO that is about 1,800 m/s short of GEO or 6.577 tonnes to GEO. Those are the goals that I suspect Vulcan Centaur 5 is being designed to meet. - Ed Kyle
I think you're right. Although, that ACES has 68 t of hydrolox and 4x RL-10. If Centaur 5 has ~50 t and 2x RL-10 it will get more like 6.5 t to GTO without SRBs and about 13 t to GTO with 6x GEM-63XL, which would be enough to hit all the EELV reference payloads and orbits by my calcs.
What are the other options? Vinci and BE-3U?
Quote from: envy887 on 01/02/2018 07:26 pmWhat are the other options? Vinci and BE-3U?I believe the BE-3U is the only other engine in the running based on statements by Tory Bruno given that XCOR has folded now. The only proposal I have heard regarding Vinci on an American rocket is for ATK's NGL (if they are looking at allies outside the US anyway not sure why the LE-5B-2 didn't make the cut).
That's the exact opposite of my recollection. The USAF study from the mid 2000s (from Barry Hellman IIRC) was showing that boostback actually made a lot of sense. I'm pretty sure I reviewed it on Selenian Boondocks under my Orbital Access Methodologies thread.http://selenianboondocks.com/2008/06/orbital-access-methodologies-part-v-boostback-tsto/
Given the uncertainties in the business case and the yet-to-be mitigated technology risks, it is premature for Air Force Space Command to program significant investments associated with the development of a RBS capability.
Quote from: Coastal Ron on 01/02/2018 06:05 pmNo, not NASA, Boeing. Boeing's customer is NASA, ULA's customer is Boeing. And Commercial Crew contracts would be considered "commercial" since they are not U.S. Government.Where the money comes from is what matters. The money is coming from the U.S. Government.
No, not NASA, Boeing. Boeing's customer is NASA, ULA's customer is Boeing. And Commercial Crew contracts would be considered "commercial" since they are not U.S. Government.
Same goes for launching Cygnus on Atlas V. To ULA those are pure commercial launches given that their customer is OrbitalATK, not NASA.Where the money ultimately comes from is of no importance. The contracting entity is however.
AFAICT, while all use the term "boostback" (or "rocketback"), all of the notional designs assume a winged first stage and horizontal landing; the SpaceX version of boosback with vertical landing was not considered.The last [3] presents the state of thinking as of 2010, at least as viewed through a more official or USAF lens (somewhere there is a more extensive companion document which I cannot locate at the moment). Among the findings:
Quote from: joek on 01/02/2018 10:44 pmAFAICT, while all use the term "boostback" (or "rocketback"), all of the notional designs assume a winged first stage and horizontal landing; the SpaceX version of boosback with vertical landing was not considered.The last [3] presents the state of thinking as of 2010, at least as viewed through a more official or USAF lens (somewhere there is a more extensive companion document which I cannot locate at the moment). Among the findings:Thanks for that. Note that the Devils all in the details, specifically the implicit assumptions about what they are talking about. Assumption. 1) Booster must return to launch site in order to give fast turnaround.In fact if you have enough of them in the pipeline for a projected launch rate that's not needed.Assumption 2) Booster will be so expensive you can't afford to have that sort of pipeline.And given the prices the USAF is used to paying they might be right. Assumption 3) Only an ORSC engine can has enough performance to do this.Since "this" is rocketback RTLS from Mach 5 (AFAIK the highest staging for F9 has been about M4. they may be right.No one seems to have considered "How about we put a landing barge 200Km down range and land the booster on that?"This is basically what happens when set so many pre conditions and constraints that you force a "shape" to the solution when the core requirement is "Build a system that allows us to launch 1 payload a day for X days." Still, nice to see an SEI report where the answer ends up being "Needs a SCramjet to make it work."
In 1998 a Japanese inventor (Yoshiyuki Ishijima) had his idea (landing a rocket on an ocean-going platform) published by the AIAA. Blue Origin later took that idea and patented it, only to have that patent over-thrown a year later.Why is it that the referenced reports from 2005 - 2010 completely overlooked an idea that had been published nearly a decade earlier?The answer is: lack of imagination.
Quote from: woods170 on 01/03/2018 06:16 amWhere the money ultimately comes from is of no importance. The contracting entity is however.We really are going to disagree on this one. Zuma is clearly a government funded enterprise, no matter that the money passes hands through a contractor or contractors. Same with commercial crew and commercial cargo and all of the ULA launch contracts for DoD and NASA. I suspect that by your definition all U.S. launches qualify as "commercial" at this time. But if the government didn't fund these endeavors, they would not happen.
Where the money ultimately comes from is of no importance. The contracting entity is however.
Quote from: edkyle99 on 01/02/2018 07:00 pmQuote from: Coastal Ron on 01/02/2018 06:05 pmBoeing's customer is NASA, ULA's customer is Boeing. And Commercial Crew contracts would be considered "commercial" since they are not U.S. Government.Where the money comes from is what matters. The money is coming from the U.S. Government.I disagree.For example: from the point of view of SpaceX the launch of Zuma is a commercial launch, albeit an unusual one. Their customer is not the government agency that operates Zuma, but Northrop Grumman. [Likewise Commercial Crew and Cygnus]Where the money ultimately comes from is of no importance. The contracting entity is however.
Quote from: Coastal Ron on 01/02/2018 06:05 pmBoeing's customer is NASA, ULA's customer is Boeing. And Commercial Crew contracts would be considered "commercial" since they are not U.S. Government.Where the money comes from is what matters. The money is coming from the U.S. Government.
Boeing's customer is NASA, ULA's customer is Boeing. And Commercial Crew contracts would be considered "commercial" since they are not U.S. Government.
The consensus among industry analysts seems to be that the government, through its direct and indirect procurement policies, provided an early and price-insensitive market that promoted movement along the learning curve and allowed the industry to decrease prices as it learned how to make its product.
Quote from: woods170 on 01/03/2018 06:16 amWhere the money ultimately comes from is of no importance. The contracting entity is however.Historians looking back at Government Support of the Semiconductor Industry: Diverse Approaches and Information Flows agree more with Ed hereQuoteThe consensus among industry analysts seems to be that the government, through its direct and indirect procurement policies, provided an early and price-insensitive market that promoted movement along the learning curve and allowed the industry to decrease prices as it learned how to make its product.This seems exactly what the process for Vulcan is hoped to be. The government, directly and indirectly, provides for a large fraction of initial business. Then after development, and the initial learning curve, the product can compete in the purely commercial market. This is not unique to Vulcan - SpaceX benefited in exactly the same way, by serving the government market to gain an initial foothold.
Historians looking back at Government Support of the Semiconductor Industry: Diverse Approaches and Information Flows agree more with Ed hereQuoteThe consensus among industry analysts seems to be that the government, through its direct and indirect procurement policies, provided an early and price-insensitive market that promoted movement along the learning curve and allowed the industry to decrease prices as it learned how to make its product.This seems exactly what the process for Vulcan is hoped to be. The government, directly and indirectly, provides for a large fraction of initial business. Then after development, and the initial learning curve, the product can compete in the purely commercial market. This is not unique to Vulcan - SpaceX benefited in exactly the same way, by serving the government market to gain an initial foothold.
Why is it that the referenced reports from 2005 - 2010 completely overlooked an idea that had been published nearly a decade earlier?
All that matters outside of policy is as woods170 says, the contract.
AFAICT, while all use the term "boostback" (or "rocketback"), all of the notional designs assume a winged first stage and horizontal landing; the SpaceX version of boosback with vertical landing was not considered.
Quote from: joek on 01/02/2018 10:44 pmAFAICT, while all use the term "boostback" (or "rocketback"), all of the notional designs assume a winged first stage and horizontal landing; the SpaceX version of boosback with vertical landing was not considered.I really don't think that was true. I know Masten and several others (including my blog posts) talked about rocket-based boostback with VTVL landing. SpaceX didn't invent something nobody had thought of, or nobody had thought was possible. They just were the first to reduce it to practice for an orbital launcher. That's a huge enough achievement that we don't need to oversell it by acting like no smart aerospace engineers existed before Elon Musk stepped onto the stage.And this is getting pretty far afield from ULA though--other than that I do agree with your preference for full-stage gas-and-go boostback VTVL recovery.~Jon
As John Simth 19 articulated... it went from: here's how you might do RTLS and why you might want to do it; to RTLS is a requirement; which then implies requirements X, Y and Z; etc., etc.In short, I would not criticize the lack of scope or imagination in those early papers; they were intentionally focused on the analysis of one solution. The lack of imagination and decrepitude was more broadly based and occurred later.