Alternatives to the ESAS

[gladiator1332]

In both the CEV/CLV forum and the SDLV/CaLV forum I have seen many who oppose the current plan. I thought it would be interesting to have a thread for some alternative designs to be put foward. Whether they are Shuttle Derived, EELV derived, completly new, or reusable is up to you to decide.

While I do like the Stick design (if NASA can get it to work) I am willing to look into new designs as well. It should be interesting to see what we come up with.

[Jim]

EELV derivatives for CEV launcher and optimized (use the best components, not the ones that employ more people) SDLV for the HLLV

[gladiator1332]

My one look into a replacement for the Stick was a CaLV derived crew launch vehicle. Picture the first stage of the CaLV with an EDS, but no SRBs. This would save costs in development, as you really would only be building one vehicle, just with a Light and Heavy version.
Unfourtanatly, as they would say on Mythbusters, this plan was busted when kraisee ran some numbers:

kraisee - 17/4/2006  8:34 PM

Okay, Gladiator - I've run some numbers on that ET launcher.   It's basic at this stage still, but it's accurate enough to prove or disprove the concept.

I'm bumed.   I liked this idea of an ET-derived booster.   It "kinda" works, but has one very serious problem which appears to kill the idea stone cold.   Let me explain.

First, configurations...

You must have a second stage, One stage just doesn't work for the reasons I guessed at previously.   I tried configs of both four and five RS-68's on the main core.   4 RS-68's doesn't work at all.

I've used the standard configuration of hardware for the CaLV for all hardware calculations, minus the boosters of course.   The optimum condition is to put only about 800tons of propellant on board the main stage so it is not filled compared to full CaLV flights.   Just for comparison, Shuttle has about 730tons in the ET.   Then you put about 100-120 tons of propellant in a standard EDS stage.   Having an optimised upper stage based on the EDS improves things by less than 5mT of final payload, so I've ignored that option due to the massive duplication of costs required.

The first stage must be throttled down in the latter part of its flight to ensure you don't exceed 3g conditions.   Left alone it peaks around 4.2g!

I simply cut the throttles to 60% just as the stage reaches 3g around 190secs.   This cut could actually be achieved either by throttling all engines down to minimum flight-rated spec, or simply turning two of the five engines off early - kinda like the Saturn-V first stage did.   Doesn't really matter which way you do it, the result is the same.

However, the dynamic pressure this vehicle experiences is a total killer for this launcher.

Even throttling the 5 RS-68's down to 60% thrust between 50 and 120secs it suffers from a massive dynamic over-pressure problem peaking at 1,100lb/sq ft about 113 seconds into the flight.   As was just mentioned over on another thread, ~800lb/sq ft is the absolute max you should ever consider for a launcher, and you need to fly manned launchers noticably below that to give the escape system some "headroom" to operate in.

Just for comparison, CLV and CaLV have been designed to both operate below 600lb/sq ft.

So, ignoring that the thing would tear itself completely apart due to the pressure conditions, if it could fly an optimised flight profile, it can theoretically loft about 56mT to the ESAS reference orbit of 30x160nM, 28.5degree.

Mythbusters would probably declare this launcher "Busted", sorry.

Ross.

In the configuation that I proposed it, the launch vehicle was dead for safety reasons, it just would not get the crew up there in one piece. I am wondering if there is a way to make this launcher work. Wasn't there a rumour that the first stage diameter of the CaLV was increasing? How would this affect the numbers?

[gladiator1332]

Jim - 25/4/2006  9:44 PM

EELV derivatives for CEV launcher and optimized (use the best components, not the ones that employ more people) SDLV for the HLLV

The only problem I find with that plan is that I don't like the idea of developing two types of vehicles. If we go with an EELV for crew launch, why not just use a larger version of the same EELV for the cargo? There were studies to done to allow a derivative of the Delta IV to lift over 100 tons...use than for the CaLV and then something smaller in the Delta IV Growth plan for the CLV.

[Jim]

gladiator1332 - 25/4/2006  9:49 PM

Jim - 25/4/2006  9:44 PMEELV derivatives for CEV launcher and optimized (use the best components, not the ones that employ more people) SDLV for the HLLV

The only problem I find with that plan is that I don't like the idea of developing two types of vehicles. If we go with an EELV for crew launch, why not just use a larger version of the same EELV for the cargo? There were studies to done to allow a derivative of the Delta IV to lift over 100 tons...use than for the CaLV and then something smaller in the Delta IV Growth plan for the CLV.

The larger Delta IV's  are nowhere like the current vehicle.  They are not optimized for the mission, they are optimized to use Delta components

The EELV's are already developed, they just need tweeking.  Anyways, separate LV families allow for some robustness.  I am talking about both EELV's for CEV, and third family for CaLV

[gladiator1332]

And when you think about it, we already are creating two new vehicles for the current plan.

[Jim]

gladiator1332 - 25/4/2006  10:09 PMAnd when you think about it, we already are creating two new vehicles for the current plan.

J-2's, SRB's and avionics are common

[Kayla]

I placed this in another thread, but it really belongs here.


The key to allowing new launch technologies (such as “EELV’s”, low cost alternatives, RLV’s,…) and their promised cost reductions to make their way into exploration in the coming decades is to develop an exploration architecture that accommodates LV’s of just about any size.  Launching most of exploration in 1 large rocket (CaLV) is only one solution.  

80% or so (~140 mT out of ~175 mT IMLEO) of a given lunar mission is propellant.  The remaining hardware comes in chunks that are <15 mT.  This provides the ideal opportunity to purchase propellant on orbit as it is loaded into the EDS launched by who ever is the lowest cost provider.  If NASA were to guarantee that they would purchase 280 mT a year of propellant on orbit from the lowest cost provider (or a few providers) this would result in the space equivalent of a gold rush.  

EELV’s may provide the early launches of propellant, due to their head start.  Low cost, but conventional rockets might soon follow.  Assuming that their costs are lower than EELV’s they would supersede the EELV’s.  And heaven forbid, someone actually develops an RLV flying say 50 times/year with 6 mT/flight (choose whatever number you want) significantly cutting launch costs, they would come to dominate.  Regardless, NASA would have created the catalyst to spur innovation, resulting in a truly affordable, sustainable and extensible exploration program.

The architecture that NASA is currently pursuing:
1)   2014 ISS: CLV/CEV ($0.5B)
2)   2018 Moon: CLV/CEV ($0.5B)  + 1 X ($1B) CaLV ($1.5B launch cost)
3)   20?? Mars: CLV/CEV ($0.5B) + 4? X ($4B) CaLV’s ($4B launch cost)
locks us into the on-going high launch costs for the indefinite future.  If you disagree with the costs I used above, use your own, the intent is still the same.

Let’s develop an architecture that not only can take advantage of emerging technology, but encourages it!  Let MSFC truly put its fantastic talent to use developing an efficient orbital maneuvering vehicle to collect these containers of LO2 and LH2 and reliably deliver them to the EDS.  Let Glenn pursue robust cost effective cryo storage and transfer.  Let Johnson evolve the CEV/TEI into a truly robust, cost & weight effective crew transport.  Let KSC determine how to effectively process all of the mission hardware that will be enabled as launch costs go through the floor.  And some people believe that we are locked into SDLV to save jobs.  Exploration offers plenty of jobs, we just have to decide if the jobs will be in SDLV for ever more, or developing and implementing new capabilities.  

Let us start the lunar missions long before 2018! Let America (NASA in partnership with industry) lead a world team exploring beyond Earths vicinity while most of us are still young enough to experience it!  Let us enable a future where space tourism is a possibility.

[vt_hokie]

My near term solution for crew transport would look a lot like this:

http://www.nasaexplores.com/show2_5_8a.php?id=03-072&gl=58

And hey, since DARPA or some agency is still funding X-37, why not kill two birds with one stone and share the development costs?  An X-37 derived small crew transport could probably be launched by a Delta IV heavy, Atlas 5 heavy, Ariane V, etc.

Longer term, I think we need to pursue cutting edge research in scramjet propulsion and other new technologies, to the point where we actually start flying hardware and moving toward real breakthroughs in next generation operational vehicles.

I really think that if "Blackstar" is real and is in fact an orbital system, or even a very high speed sub-orbital system, it would be a travesty for the knowledge and experience gained to go to waste.  So, I hope that it emerges from the black world sooner rather than later.

[Jim]

vt_hokie - 26/4/2006  12:30 AMMy near term solution for crew transport would look a lot like this:http://www.nasaexplores.com/show2_5_8a.php?id=03-072&gl=58And hey, since DARPA or some agency is still funding X-37, why not kill two birds with one stone and share the development costs?  An X-37 derived small crew transport could probably be launched by a Delta IV heavy, Atlas 5 heavy, Ariane V, etc.Longer term, I think we need to pursue cutting edge research in scramjet propulsion and other new technologies, to the point where we actually start flying hardware and moving toward real breakthroughs in next generation operational vehicles.I really think that if "Blackstar" is real and is in fact an orbital system, or even a very high speed sub-orbital system, it would be a travesty for the knowledge and experience gained to go to waste.  So, I hope that it emerges from the black world sooner rather than later.

The current X-37 is only for landing tests.  The X-37 for space was hopeless, too many issues,  that is why the orbital version got cancelled.  Also launching winged vehicles on ELV's was turning out to be harder than thought.  The aeroloads imposed by the craft are way above what current LV are designed to.  Almost need a new design dedicated booster.  The X-37 orbital test was to get around it because it was in a fairing.The TPS and aeroshape of the X-37 is not proven.  It could be a dead end and where are you, then.RLV's, for the near term (20 years), is not going to be cost effective.  they might be cool, but Flight rates don't support the buying down the initial costs, and the fixed costs are still up there.  We still have 747's, B-52's, C-5's, Delta II's flying.  Old is not bad.  What needs to be done is reduce the number of people involved in processing LV's, that is where the money gets used up.

[vt_hokie]

The current X-37 is only for landing tests.  

True, but I assume that DARPA is still funding the drop tests because they see some potential long term benefit.

The X-37 for space was hopeless, too many issues,  that is why the orbital version got cancelled.

So, it has been cancelled?  That's too bad.  

Also launching winged vehicles on ELV's was turning out to be harder than thought.  The aeroloads imposed by the craft are way above what current LV are designed to.  Almost need a new design dedicated booster.

Bummer.  

The X-37 orbital test was to get around it because it was in a fairing.The TPS and aeroshape of the X-37 is not proven.  It could be a dead end and where are you, then.

Well, any new design is going to have issues.  But if you never try to tackle new challenges, then you never advance.  And where are you then?

RLV's, for the near term (20 years), is not going to be cost effective.  they might be cool, but Flight rates don't support the buying down the initial costs, and the fixed costs are still up there.  We still have 747's, B-52's, C-5's, Delta II's flying.  Old is not bad.  What needs to be done is reduce the number of people involved in processing LV's, that is where the money gets used up.

Seems like a Catch-22 situation then.  Flight rates won't increase until a more affordable means of transport is available.  You say we shouldn't worry about more affordable transport until flight rates increase.  I guess I'm more in the "build it and they will come" camp.  Imagine if we had something with the same fixed costs as the space shuttle, but capable of flying two dozen times a year instead of 3 or 4.  We'd have completed ISS years ago and would now be focused on research productivity aboard the station, not on just getting the darn thing finished.

[Jim]

RLV's and winged entry vehicles  vs ELV's and capsules are much like the SST vs std aircraft.   Elegance is not necessary We just need a less expensive and robust way to get a few people to and from space.The Shuttle is going the way of the Concorde.

[vt_hokie]

Well, from an enthusiast's point of view, I just cannot get excited over or inspired by capsules, just as I don't get too excited by 737's.  I'll always hold a special place in my heart for elegant vehicles like the Concorde and the Space Shuttle!  I hope that if I ever have children, they have something more than capsules and Mach 0.8 cattle herders to inspire them.

[Jim]

vt_hokie - 26/4/2006  7:38 AMWell, from an enthusiast's point of view, I just cannot get excited over or inspired by capsules, just as I don't get too excited by 737's.  I'll always hold a special place in my heart for elegant vehicles like the Concorde and the Space Shuttle!  I hope that if I ever have children, they have something more than capsules and Mach 0.8 cattle herders to inspire them.

The all mighty $ rulesBut it is not how you get there, it what you do when you get there.A vacation to Hawaii isn't the plane flight to and from there, it's the time you spend on the islands.F-1 racer looks better than a mini van, but what gets the kids to and from soccer practices.Shall I go on?

[vt_hokie]

I still maintain that reusable winged or lifting body space planes offer several inherent advantages over ballistic capsules.  So, I don't think the practicality argument is quite so clear cut.