Application of value-centric design to space architectures: The case of fractionated spacecraft

Space 2008 Conference

Volumn , Issue , 2008, Pages

  Brown, Owen ^a   Eremenko, Paul ^b  

^a DEFENSE ADVANCED RESEARCH PROJECTS AGENCY   (United States)

^b BOOZ ALLEN HAMILTON   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ARCHITECTURE; ORBITS;

ARCHITECTURAL SOLUTIONS; CLUSTER ORBITS; DESIGN METHODOLOGY; FRACTIONATED SPACECRAFT; GOVERNMENT PROCUREMENT; SPACE ARCHITECTURE; SPACECRAFT MODULES; VALUE PROPOSITION;

DESIGN;

EID: 78049524606     PISSN: None     EISSN: None     Source Type: Conference Proceeding    
DOI: 10.2514/6.2008-7869     Document Type: Conference Paper

References (35)

1. Brown, O. & Eremenko, P., "The Value Proposition for Fractionated Space Architectures," AIAA-2006- 7506, AIAA Space 2006, San Jose, CA (2006).
2. "DARPA Awards Contracts for Fractionated Spacecraft Program," Press Release, Defense Advanced Research Projects Agency, Feb. 26, 2008, available at http://www.darpa.mil/body/news/2008/F6.pdf.
3. Note that in light of the preceding discussion the notion of a single fractionated "spacecraft" can get fuzzy. We prefer to talk about systems rather than individual spacecraft. This is because a single set of infrastructure modules can support multiple payloads and multiple missions. Furthermore, these can change over time, merge with other clusters, and otherwise be reconfigured. Where a single spacecraft ends and another begins ceases to be a meaningful inquiry.
4. These arguments are also explored at length in Saleh, J., "Flawed Metrics: Satellite Cost per Transponder and Cost per Day," IEEE Transactions on Aerospace and Electronic Systems, Vol. 44, No. 1, pp. 147-156 (2008).
5. Wright, T.P., "Factors Affecting the Cost of Airplanes," Journal of Aeronautical Sciences, Vol. 3, No. 4, pp. 122-128 (1936).
6. The Iridium, Globalstar, and Orbcomm constellations are, perhaps, the highest-volume space systems to date. And while the learning curve effects there were significant, anecdotal evidence suggests that no fundamental transformation of Lockheed Martin's or Loral's production processes was warranted by quantities in the dozens.
7. One subject which we touched upon in the introduction, but have not explicitly enumerated in Table 1 or the subsequent discussion is that of amortizing costs of fractionated systems across multiple missions through shared infrastructure modules. This fundamentally alters the economics of space systems and makes it virtually impossible to compare fractionated to monolithic systems. For that reason, the subject warrants a separate discussion in a future essay and is not addressed in any detail here.
8. Though we certainly do not dispute that the addition of wireless links and other fractionation-related subsystems will introduce new failure modes into the analysis.
9. Taleb, N., The Black Swan: Impact of the Highly Improbable, Random House (2007).
10. Carlson, J.M. & Doyle, J., "Complexity and Robustness," Proceedings of the National Academy of Sciences, Vol. 99, Suppl. 1, pp. 2538-2545 (2002).
11. See, e.g., note 1.
12. See, e.g., Saleh, J. et al., "Flexibility and the Value of On-Orbit Servicing: New Customer-Centric Perspective," Journal of Spacecraft and Rockets, Vol. 40, No. 2, pp. 279-291 (2003);.
13. Nilchiani, R. & Hastings, D., "Measuring the Value of Flexibility in Space Systems: A Six-Element Framework," Systems Engineering, Vol. 10, No. 1, pp. 26-44 (2007).
14. Whether we treat the value and cost as discounted to the present is immaterial to our discussion here. A quantitative treatment would require the determination of an appropriate discount rate. Interestingly, while economically-savvy branches of the federal government routinely rely on Treasury Note rates for discounting future cash flows (see, e.g., Nussle, J., "2008 Discount Rates for OMB Circular No. A-94," OMB Memo M-08-08, White House Office of Management and Budget, Jan. 14, 2008), Congress and the Department of Defense use an effective discount rate of zero in procurement planning.
15. Note that this assumption lies in great contrast to some contemporary thought that small spacecraft can not provide capability on par with large ones." Here we suggest otherwise, i.e., that small spacecraft together can create value (based solely on static capability; irrespective of the flexibility and robustness that are the major focus of the rest of this essay) at least equal to that of large monoliths. Of course, we maintain that clever combinations of small spacecraft-what we call fractionated clusters-offer more value than traditional monoliths.
16. th AIAA Responsive Space Conference, Los Angeles, CA (2006).
17. Guikema, S. & Paté-Cornell, N., "Bayesian Analysis of Launch Vehicle Success Rates," Journal of Spacecraft and Rockets, Vol. 41, No. 1, pp. 93-102 (2004).
18. Arena, M. et al., "Historical Cost Growth of Completed Weapon System Programs," TR-343-AF, RAND Corporation, Santa Monica, CA (2006).
19. Sullivan, B. & Akin, D., "A Survey of Serviceable Spacecraft Failures," AIAA-2001-4540, AIAA Space 2001, Albuquerque, NM (2001).
20. Moore, G., "Cramming More Components onto Integrated Circuits," Electronics, Vol. 38, No. 8 (1965).
21. Unfortunately, it is difficult to develop design rules-of-thumb based on value that are useful at the subsystem or component level. While it may be easy to use rough relationships for estimating cost on the basis of size, weight, and power of subsystems and components (it scales roughly linearly or as a power law with an exponent that is not too far above 1.0), the relationship between value and most concrete design variables that are of interest during detailed design trades is obscure. Hence our focus on architectural design variables that have clear relationships to the lifecycle value streams.
22. The classic overview of multi-attribute utility theory and related techniques is Keeney, R. & Raiffa, H., Decisions with Multiple Objectives: Preferences and Value Trade-Offs, Cambridge University Press, Cambridge, UK (1993).
23. An excellent treatise on real options generally is Trigeorgis, L., Real Options: Managerial Flexibility and Strategy in Resource Allocation, MIT Press, Cambridge, MA (1996).
24. This idea is explored in greater depth in Brown, O., "Reducing Risk of Large Scale Space Systems Using a Modular Architecture," Space Systems Engineering & Risk Management Symposium, The Aerospace Corporation, Los Angeles, CA (2004).
25. An illustrative attempt at capturing the value of fractionated spacecraft in comparison to analogous monolithic systems using the lifecycle cost under uncertainty method is described in Brown, O. et al., "System Lifecycle Cost Under Uncertainty as a Design Metric Encompassing the Value of Architectural Flexibility," AIAA-2007-6023, AIAA Space 2007, Long Beach, CA (2007).
26. Adapted from Systems Engineering Fundamentals, Defense Acquisition University Press (2001).
27. Systems Engineering Fundamentals, Ibid. at p. 112.
28. So much so, in fact, that gross take-off weight for aircraft and launch mass for spacecraft is frequently a stakeholder-specified requirement-in stark violation of best systems engineering practices which seek to confine stakeholder requirements to architecture-independent mission performance attributes.
29. This is not to discount the importance of ensuring cost conformance with fiscal constraints. The overall cost contribution to net value can, of course, be an explicit output and parameter for the elimination of architectures that do not conform to budgetary limitations.
30. We are aware of the potential objection that this approach leaves open the possibility that a suboptimal design decision (from a net value perspective) would be made at a subsystem or component level since the traditional process would likely rely on cost or mass minimization. Short of turning the value tool into a complete multi-disciplinary optimization engine, we do not know of a practical solution to this problem. Our suggestion is that the key drivers of architectural flexibility and robustness be identified at the outset and included in the architectural design vector which the value methodology then optimizes at the outset of the systems engineering process.
31. Hitch, C. & McKean, R., The Economics of Defense in the Nuclear Age, RAND Corporation Report R-346, p. 175 (1960).
32. Hitch, C. & McKean, R., The Economics of Defense in the Nuclear Age, RAND Corporation Report R-346, (1960) Ibid. at p. 185.
33. Hitch, C., Decision-Making for Defense, University of California Press, p. 52 (1965).
34. In the past few decades, one of the much-touted reforms to the procurement process has been that of "best-value contracting," whereby more than just the cost of a system is considered. Specifically, the system that offers the "best value to the government" is selected. Unfortunately, value is defined purely as a function of cost, performance, quality, and schedule (and not other non-performance attributes of the architecture), and provides no method for weighting or otherwise combining these so-called key performance indicators (KPIs) into a single measure of value. Flexibility and robustness are ignored altogether, and the statutory requirement is only to provide a ranked list of these KPIs when used as source selection criteria (and not their actual weighting) in competitive procurements.
35. The performers for the preliminary design phase of the program include teams led by Orbital Sciences, Northrop Grumman, Lockheed Martin, and Boeing.