The following baseline (1 through 19 below) is from the NASA Access to Space Study, Annual Recurring Cost backup.
All costs are in FY94 $M.
1) Total ET 372.4 2) Total SRM 404.2 3) Total SRB 152.0 4) Total Engine (Sustaining Eng'nrg) 125.3 5) Total Orbiter & GFE (JSC) 177.3 6) Total Orbiter Logistics & GSE (KSC) 174.0 7) Total Propellant (from Launch Ops- KSC) 16.5 8) Total Launch Operations (KSC) 619.4 9) Total Payload Operations (KSC) 35.7 10) Total Mission Operations (JSC) 292.6 11) Total Crew Operations (JSC) 50.7 12) Total Crew Training & Medical Ops (JSC) 21.2 13) Total Program Office/HQ 180.3 14) Total Institution 477.6 15) Total PMS 75.8 16) Total Network Support 72.3 17) Total Systems Engineering 128.4 18) Total STS Capability Development 672.5 19) Total Shuttle Prod. & Oper. Capability 925.2 -------------------------------------------------------------------- Total Space Transportation System $4973.4M
Now, assume a Tri-Propellant next generation Reusable Launch Vehicle (RLV). In particular reference RLV CONCEPT STUDY, TEAM REVIEW, MSFC, OCT 3-7, 1994, for information on the direction of the particular RLV concept discussed here as well as the Technology Summaries and Implementation Plans from the RLV Propulsion and Structures Synergy Teams and RLV program documents.
1) Total ET: $372.4M
Subtract: The whole amount. Use zero for the Tripropellant SSTO.
Rationale: The costs incurred here are primarily those of production for an expendable launch element. The remainder, although not specifically production, are directly caused by a need to support the main production component. For SSTO options it can be assumed the one time development and production of one or more vehicles is not accompanied by a constant yearly production of entirely new vehicles.
2) Total SRM: $404.2M
Subtract: The whole amount. Use zero for the Tripropellant SSTO.
Rationale: Same as for ET Total. Even though this element is semi-reusable and refurbished it is not an element likely to carry over in scope to an SSTO type vehicle.
Note: A 65Klb due east payload option in the MSFC RLV concept does look into SRB's for performance enhancement and a larger payload bay to capture the heavier payload needs and reduce the core vehicle size. If this is pursued, a sizable portion of the current costs, 404.2 for SRM and 152.0 for SRB, could easily carry over into the next generation vehicle. Also, launch site and non-launch site recurring costs would have to be adjusted upwards negating the deletion of this flight element.
3) Total SRB: $152.0M
Subtract: The whole amount. Use zero for the Tripropellant SSTO.
Rationale: Same as for ET Total. Even though this element is semi-reusable and refurbished it is not an element likely to carry over in scope to an SSTO type vehicle.
Note: See Total SRM.
4) Total Engine (Sustaining Engineering): $125.3M
Add: (7/3)*125.3=292.4. Given 3 SSME's with a demonstrated history versus the still in development 7 RD-704's for this concept it can reasonably be assumed a factor of 7/3 can be applied to this line item. This is very success oriented - disregarding the increased complexity associated with a 3rd and different fluid commodity added to system.
Rationale: No systems have been appreciably eliminated or integrated in the RD-704 versus an SSME. One system, POGO, presently not included, is not precluded by configurations being considered for an RD-704 system layout and a computerized POGO suppression system is being considered on the RLV TD+D list for MPS. GN2/GHe is required for IPS purge on both LOX and LH2 TP's. No work is planned deleted versus an SSME and some work is added such as installing the hypergolic starter cartridges. If engines are removed every flow actual work will again be added to, not subtracted (installing aft access kit, disassembling heat shielding, actual removal, breaking interfaces, inspecting interfaces, reassembling interfaces, leak checks of interfaces, etc...) The 7/3 assumption is likely extremely success oriented at this point based solely on the information available.
Also, the additional hardware (more TP's, high pressure valving, feeds, press, fluid and electrical interfaces, sensors, controller complexity) will again make this additional cost factor of 7/3 a success oriented number. It would likely be higher upon more detailed analysis. Gains due to common hardware (a non-linear relationship where the last engine costs much less than the first) are very likely not seen in this component which deals with sustaining engineering. As complexity and parts count (simulations, anomalies, inventory, refurb, spares, transportation) increase this component would also require an increase in expenditures.
5) Total Orbiter & GFE (JSC): $177.3M
Subtract: Use a corrected value of 96.5M.
Rationale: This is a very success oriented estimate. The increase in the number of systems for a tripropellant vehicle versus a bipropellant will likely increase this cost which is mostly the cost of sustaining engineering (108.3 out of 177.3) The addition of more potential leakage sources, an increase in the number of different fluids (no hypergols but added RP-1 and still have self contained smaller quantities of hypers) and the stand-alone nature of the MPS/engine (non-integration with OMS and an RCS which is RP/LOX) would likely make this number actually higher. The additional interfaces, components and onboard systems for a 3rd commodity as well as not having eliminated GHe or GN2 usage would likely make this value higher.
The deletion of the manned flight element will result in the deletion of this part (50.9) of the 177.3 total. Also, Orbiter/ET disconnects (7.7) would be deleted. The sustaining engineering portion (108.3) and the flight data support (10.4), would, however, arguably be increased in this line item and negated entirely by the additional complexity of a 3rd system for the tripropellant SSTO.
The deletion of ECLSS from the vehicle (unmanned) would have an impact on this cost component. Using a sustaining engineering of about 3/4 that of MPS for ECLSS but increasing the MPS by 1/3 for the added systems would give a gain of about 50% for a component that is estimated at 25%. The total gain is the 12.5%.
This results in a total value of: 177.3-50.9-7.7-(0.125)(177.3)=96.5M.
6) Total Orbiter Logistics & GSE (KSC): $174.0M
Subtract: Use a corrected value of 154.3M.
Rationale: This value is primarily spares, overhaul and repair, logistics and procurement manpower and tile spares and maintenance.
For an SSTO vehicle, assume for tile:
No damage caused by debris from other elements (ET or SRB.)
No ET/Orbiter doors (a tile interface.)
Use of the newer toughened ceramic coating on the tile (more robust.)
Waterproofing still required.
Increased surface area. TBD.
Based on this success oriented approach, reduce this number to 25% of present STS value. Vehicle engineering assessment is the more robust tile may not be as damage free as planned and that design solutions to areas such as doors and probes are TBD.
For the remaining (44.3, 64.6 and 33.1 and 5.7) for spares, overhaul and repair, logistics and procurement manpower, and GSE sustaining engineering respectively, the value will be held constant even though the increase in the system complexity bought about by a tripropellant option based on parts count alone would likely increase these numbers. A 1/3rd increase in parts count for a major system such as propulsion automatically adversely affects reliability.
This results in a final value of: 174-0.75(26.3)= 154.3M.
7) Total Propellant (from Launch Ops (KSC)): $16.5M
Same: Use the same number for Total Propellant (from Launch Ops- KSC)
Rationale: The total propellant load by weight will be close to that used presently (minus SRB's of course). Infrastructure costs and actual costs of the 3rd propellant would actually make this number higher elsewhere such as in facilities and manpower. Use of the same cost is a likely low estimate.
8) Total Launch Operations (KSC): $619.4M
Subtract: Use 535.6
Rationale: By line item as follows:
a) Orbiter Operations: Total is 132.4M.
ECLSS is deleted.
Tripropellant systems have been added (MPS feeds, press, valves, TVC, etc...) More engines.
Increase this cost by 25% given intensiveness associated with engines and MPS.
i.e. use 132.4+(0.25)(132.4)=165.5
b) SRB Operations: Total is 16.7M. Delete. See note for (2)SRM and (3)SRB
c) ET Operations: Total is 4.3M. Not deleted. Has been absorbed into the vehicle and a tank has been added along with the interfaces.
i.e. success oriented, use the same value.
d) Launch Operations: Total is 41.2M.
Assume a success oriented reduction here of 50% due to not having diverse elements to stack or integrate.
i.e. use (0.50)(41.2)=20.6
e) Payload Operations: Total is 11.4M.
Assume a success oriented reduction here of 50% given current course toward reducing this interfaces impact on the vehicle.
i.e. use (0.50)(11.4)=5.7
f) Systems Engineering: Total is 11.3M.
i.e. success oriented, use the same value.
g) Facility Operations and Maintenance: Total is 113.6M.
Current plans slate 1 turnaround bay for each vehicle and 1 maintenance bay (where more work is performed) and service/deservice bay for the fleet (1 vehicle or more...) Some current facilities would be mothballed (1 pad at 10M, the VAB at 4.3, the MLP's at 6.6, the OPF's at 5.0, the HMF at 1.4, Transporters at 1.6, the CLS's at 0.7, the RPSF at 0.7, SRB retrieval ships at 1.8) but new ones are added (erectors TBD, new bays TBD, new service bay TBD, new maintenance bay TBD, RP1 facilities at the pad.)
LES, facility systems, maintenance service contracts, inventory spares and repair and system equipment are also on this list.
Assume a success oriented reduction of 25% based solely on major facility shutdowns such as the VAB and hyper facilities. Given the current concept lack of definition as to direction here (weather or not a drastic launch site facility reduction is or is not a high priority goal) no more can reasonably be assumed.
Use (0.75)(113.6)=85.2.
h) LPS Instrumentation and Calibration: Total is 50.6M. Assume the use of up to date control systems (automation, monitoring, etc...) However, also assume that these commercial systems are improved upon as part of the development focus (to develop new technologies with application to the commercial sector, not just to use what the commercial sector already has.) Assume a success oriented 90% reduction here due to this increased ease of use.
Use (0.10)(50.6)=5.1
i) Modifications: Total is 13.9M.
Use the same value.
j) Technical Operations Support: Total is 113.1M.
Use the same value.
k) Program Operations Support: Total is 32.5M.
Use the same value.
l) Communications: Total is 19.7M.
Use the same value.
m) Base Operations Contract: Total is 20.8M.
Use the same value.
n) Launch Support Services: Total is 35.0M.
Origin is TBD. For now, use the same number.
o) Weather Support: Total is 2.9M.
Use the same number.
Sum of the above is: 535.6
9) Total Payload Operations (KSC): $35.7M
Subtract: Use a new gain for Total Payload Operations (KSC)
Rationale: Assume a technology hurdle is overcome and this is reduced by 95%. Use 0.05*35.7=1.8. Success oriented.
10) Total Mission Operations (JSC): $292.6M.
Subtract: Use a new gain for Total Mission Operations (JSC)
Rationale: Assume a major gain here due to consolidation - move to the launch site and an associated integration gain. Also, assume a major gain in automation. Use 25% of the present number.
This would be (0.25)(292.6)=73.1
11) Total Crew Operations (JSC): $50.7M.
Subtract: The whole amount.
Rationale: No crew.
12) Total Crew Training & Medical Ops (JSC): $21.2M.
Subtract: The whole amount.
Rationale: No crew.
13) Total Program Office HQ: $180.3M.
Same: Total Program Office/HQ.
Rationale: The complexity of the tripropellant option, lack of major system integration, added international interface, and general lack of difference versus the present STS reasonably leaves this at shuttle levels.
14) Total Institution: $477.6M.
Subtract: Use 404.2M.
Rationale: Assume integration of launch and mission functions cuts JSC institutional costs by 50%. This would be 477.6-0.50(146.9)=404.2. Also, other areas such as SSC costs are likely to increase. To even consider removing engines every flow or performing any intrusive work in the vehicle aft will quickly negate this gain.
15) Total PMS: $75.8M.
Subtract: Reduce this number by 25%.
Rationale: Assume efficiency gains due to overall federal workforce reductions which are current goals.
Use (0.75)(75.8)=56.85
16) Total Network Support: $72.3M.
Same: Use the same value.
Rationale: No information found indicates plans for deletion.
17) Total Systems Engineering: $128.4M.
Subtract: Use the same value.
Rationale: These areas are primarily programmatic and would reasonably remain at shuttle levels for a tripropellant design as per the MSFC concept.
18) Total STS Capability Development: $672.5M
Same: Use 672.5
Rationale: Ref. (19) below.
19) Total Shuttle Prod.+Oper. Capability: $925.2M
Same: Use 925.2
Rationale: No orbiters are presently in production yet capability development (new engines, turbopumps, glass cockpit, etc...mods) still draw this funding level for a mature system 13 years after 1st launch. Initial SSTO Tripropellant levels can reasonably be assumed to be as high given the combination of uncertainties with a tripropellant approach which is currently a paper engine (high programmatic risk) and the lack of benefit (toward enabling the goal of drastically reducing the cost of access to space) inherent in the design. Savings in SRB production of 52.8 should easily be outweighed by the additional engines on this concept.
Adding up the total costs...($M) 1) Total ET 0 2) Total SRM 0 3) Total SRB 0 4) Total Engine (Sustaining Eng'nrg) 292.4 5) Total SSTO Triprop. & GFE (JSC) 96.5 6) Total SSTO Triprop. Log. & GSE(KSC) 154.3 7) Total Propellant (from Launch Ops- KSC) 16.5 8) Total Launch Operations (KSC) 535.6 9) Total Payload Operations (KSC) 1.8 10) Total Mission Operations (KSC) 73.1 11) Total Crew Operations (JSC) 0 12) Total Crew Training & Medical Ops (JSC) 0 13) Total Program Office/HQ 180.3 14) Total Institution 404.2 15) Total PMS 56.85 16) Total Network Support 72.3 17) Total Systems Engineering 128.4 18) Total SSTO Triprop.Capability Development 672.5 19) Total SSTO Triprop. Prod. & Oper. Capability 925.2 -------------------------------------------------------------------- Total Next Generation RLV (if Tripropellant Concept) $3609.95M Note: Saved @$1363M.
As a final correction, subtract another 25% off this total to correct for STS budget decline in the next few years which in turn will create productivity increases passed along to this SSTO concept.
Final=(0.75)(3610)=$2708M. Refer to this as the "MT-option" for MSFC tripropellant.
IMPLICATIONS:
Now, recall that the STS budget requirements were based on a vehicle launching 7 times per year. This is roughly a productivity of 710M/per launch. For the SSTO triprop concept, given the increase in the propulsion system complexity and that this is a major component of launch site processing, a gain of no more than 33% on the productivity of any one vehicle (regardless of fleet size) would indicate that with these same resources the total gain for a similar size fleet of 4 would be about 2 to 3 launches. This brings the total to about 10 launches per year at 2708M or 270.8M/per launch, a 62% gain.
Is this still unacceptable? The payload cost must be added to this cost to determine a customer cost. It is highly unlikely that this value is low enough to bring about an expansion of space activity. It is likely costs would have to be significantly less than the above to bring about increased access to space, commercial ventures or otherwise.
There is a sensitivity to launch rate. If the rate is increased to double that with the present fleet (14 launches per year, assuming for this concept a configuration-unlikely increase in through-put at the launch site) the cost would still be 193.4M/per launch. Even a quadrupling to 28 launches (a useful number for congressional quoting but just a gedanken-fantasy for this concept) would be 96.7M/per launch. This is a success compared to STS - it's merely 13.6% of the current STS cost. Still, it may just as well be the 710M/launch of STS as far as all but the largest financial entities (government and mega-corps) are concerned. It is still a value unlikely to bring about routine, affordable access to space.
Reassessing the costs, the largest remaining drivers are:
Prod. & Oper. Capability 925.2 Capability Development 672.5 Launch Operations 535.6 Engine Sust.Eng'nrg 292.4 Institution 404.2 Program Office/HQ 180.3 Logistics/GSE 154.3 Total= $3164.5M or 88% of the total.
Consider the sensitivity of these simply to parts count. The first item, production and operating capability is driven primarily by engines, upgrades and spares. Launch operations is driven primarily by the manpower intensive nature of the vehicle test and checkout and subsequent need for spares. Engine sustaining engineering is driven by parts, subsystems and complexity. Create a system and someone will be assigned sustaining engineering. Institution is driven by the complexity of the vehicle. Logistics is driven by parts - again. Program office costs are driven by complexity again such as systems and programs for those systems. If launch costs can drive down capability development (primarily payloads) it will not be done simply by deleting expendable program elements but rather by a wholesale deletion of systems, sub-systems, and parts on the entire vehicle - especially on a main driver such as the propulsion system. Deletion of major integration tasks are just an enabling step toward a truly supportable design. Given current experience with the RLV effort and the notable "same old ways of doing business" it is likely the MT-option, if pursued, will lead to a cost scenario such as that previously outlined - optimistically. Certain assumptions (the elimination of JSC as launch control and no augmentation such as with SRB's or hybrids) are not discounted and would only make the costs escalate further. It would be very easy then to justify STS for an extended period of time rather than move on to a nexgen vehicle. Again, truly supportable designs will not come about simply with the deletion of integration tasks and marginal technology improvements, but rather through the wholesale deletion of systems, sub-systems and parts on the vehicle through a major assault on vehicle and programmatic complexity always with one single minded goal - affordability - not to preserve a space launch capability or capture existing market share, but rather, to create and grow new markets and possibilities that did not exist before.
Consider, however, a change in the MT-scenario assessed previously - it assumes a vehicle that would operate to replace STS. Is this an artificially limiting assumption?
ALTERNATE POSSIBILITIES:
If our goal is increased access to space, commercial and otherwise, because it has been made routine and affordable, then it is not this next generation vehicles goal to replace STS. Consider the following "growth" or G-scenario.
First, a separate program with much limited funding is formed. This avoids the carryover of unnecessary baggage from the current STS program. Current STS operations continue a drawdown cost wise driven by budget pressures. The new vehicle characteristics are such that: (a) TPS is robust and maintenance free requiring zero waterproofing or repair from flight to flight (b) Propulsion is highly integrated - perhaps 4 nozzles and combustion chambers fed by a 1:2 ratio of pump sets, LOX/LH2, to CC's (c) Much of MPS doubles as OMS at the hardware level (d) There is only one goal in this program - lower the cost of access to space. It is the only driver. Higher program risks are accepted pursuing technologies with high potential for benefit. Technical options that add systems and complexity are never considered except as last resorts after having pursued doing the job without those added systems or active components and proven the situation untenable. (e) Minimal if any infrastructure is the goal. Pursue this program away from existing infrastructure. Do not "maximize the use of existing facilities."
Perhaps this creates the possibility of demonstrating a quantum leap in a vehicle efficiency and effectiveness - even if just a one vehicle fleet. Development costs are then absorbed by the government venture (no chance of a reasonable return on investment in a short time frame) but only in the immediate confines of this particular government venture. Commercial activity would not have to repeat the development experience - technical surprises, failures, redirection inefficiencies - but rather, could proceed to leapfrog directly into a commercial operational environment. Competition could conceivably create a cascade effect, driving access costs even further down than in the government arena. Eventually, a program such as STS is replaced (terminated) not by a follow on program (except for a short time period perhaps) but by commercial contracts at a fraction of today's costs. As usual, custom, particular government needs may require an operation away from the commercial activity similar to the way the DOD still buys and uses unique transport aircraft but most traffic and growth is private and commercial. In turn, the sideline development effort is replaced (evolved) into the only major remaining part of the government enterprise, to develop new space vehicles and technologies - not to operate them, but in effect to build another even better version than that which sets off this chain of events.
CONCLUSIONS:
(1) SSTO "alone" will not drive down launch costs. This will only be done through a wholesale deletion of systems, sub-systems, and parts on the entire vehicle - especially on a main driver such as the propulsion system. Deletion of major integration tasks are just an enabling step toward a truly supportable design.
(2) The previous design paradigm will only be enabled by a redesign of "basic assumptions" such as (a) the goal of the next generation reusable launch vehicle and (b) the structure of the organizations tasked to reach this goal.
This has been a "gedanken" (thought) experiment to try to get a handle on the possibilities for the next generation vehicle. I hope you find this approach useful.
NOTE: Original as a note in response to a question...
Edgar Zapata
Return to KSC Next Gen Site
Edgar Zapata, NASA Kennedy Space Center
Shuttle Process Engineering Directorate, Fluid Systems Division