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This mini-workshop presentation examines the reliability of university-class spacecraft, with a focus on CubeSats, and highlights the challenges and successes in their design, fabrication, integration, and operations. The presentation also discusses the role of training in mission success and the need for external reviews and functional testing. Presented by Michael Swartwout from Saint Louis University at the NASA Academy of Aerospace Quality Mini-Workshop.
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Reliability of University-Class Spacecraft:A Statistical Look Michael SwartwoutSaint Louis University NASA Academy of Aerospace Quality Mini-WorkshopCape Canaveral, FL22 March 2012
“University-Class Satellite” • Working definition • Self-contained device with independent communications, command & control • Untrained personnel (i.e. students) have key roles in design, fabrication, integration and operations • Training is at least as important as the rest of the mission • Excluded (by definition) • Many, many satellites with strong university participation (especially as science PI) • Most Amateur satellites • Exclusion does not imply lack of educational value!
The Numbers • Growth! • 10th: 1994 (13 years) • 50th: 2003 (9 years) • 100th: 2008 (5 years) • 150th: 2012 (4 years) • Is “steady state” 8 or 15 (or 25?)
What Breaks? What Breaks? • Radiation: 1* • Launch interface: 1 • Launch thermal: 1 • ADCS: 2 • Mechanism: 3 • Communications: 5½ • CPU lockup: 2 • Power: 5½ • DOA: 11* 32 of 120 orbited spacecraft “failed” • What Doesn’t Break? • Structures • Thermal* • Commercial Electronics in Radiation Environment* Lifetime reduction Perhaps we should worry more about system-level functional testingand less (?) about the space environment…
It Helps to Be Somebody (but not as much, now) • Flagship School • Significant government sponsorship • Often a leading space education/technology program for that nation • Independent School • Self-funded or sponsored (at school’s initiative) • On their own for launches
To Grossly Oversimplify • Flagship schools • Build “real” missions that work (90% success) • Use CubeSats as stepping-stones • Sustain programs around a larger (20-100 kg) bus • Move up the “value chain” and out of the university class • Independent schools • Build one satellite that might work (58%), then fly no more (75% of schools) • BuildCubeSats and, if sustained, it’s a series ofE-class CubeSats
Repeat Business: Encouraging Trends! • Flagship Schools • 29 schools built 67 spacecraft (47%) • 8 schools built 46 spacecraft • 5 have graduated • Independent Schools • 54 schools built 76 satellites (53%) • 45 schools built 44 one-shot missions(but 23 launched in 2010-2011!) • 10 active, repeated-flight schools (up from 4 in 2009!) • 1 has graduated
Shortest-Ever Course on CubeSats • Twiggs (Stanford) and Puig-Suari (Cal Poly) defined a standard for carrying 10 cm, 1 kg cubes into space • [The real innovation was the P-POD] • Timeline • 1999 concept definition • 2003 first flight • 2010 70th flight • 2012 NASA selects 33 CubeSats to fly (backlog of 59)
Here Come the CubeSats (and Friends) 85 CubeSats in 12 years 79 in the “CubeSat Era” (2003-now) 30 Manifested for 2012 (or is it 50?) 2012
What happened? • Ten years of groundwork • Infrastructure and capabilities built up through the University Nanosat Program (AFOSR/AFRL) • Government/industry funding in CubeSat technologies (e.g., NRO/Colony) • Strategic government investment in university CubeSats • National Science Foundation (2008) • ESA Vega (2008) • NASA ELaNa (2010) • “Will this be on the final?”’ • NSF, ESA, NASA required missions • Suddenly, universities can find missions!
Conclusions & Recommendations • University-class spacecraft are real, in growing (ballooning) numbers • Thank you, NASA! • Thank you, AFRL! • A 25% failure rate isn’t great (but it’s better than 50%) • Flagships get all the breaks • Independents, well, break • Universities need help • External reviews • Emphasis on functional testing
Reliability of University-Class Spacecraft:A Statistical Look Michael SwartwoutSaint Louis University NASA Academy of Aerospace Quality Mini-WorkshopCape Canaveral, FL22 March 2012