Reliability of University-Class Spacecraft:
A Statistical Look
Michael SwartwoutSaint Louis University
NASA Academy of Aerospace Quality Mini-Workshop
Cape Canaveral, FL22 March 2012
SwartwoutReliability of University-Class Spacecraft
“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!
SwartwoutReliability of University-Class Spacecraft
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Spacecraft On Rockets
The NumbersGrowth!• 10th: 1994 (13 years)• 50th: 2003 (9 years)• 100th: 2008 (5 years)• 150th: 2012 (4 years)Is “steady state” 8 or 15
(or 25?)
SwartwoutReliability of University-Class Spacecraft
Mission Lifetime
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Not yet
> 3 yrs
1-3 yrs
0-1 yr
S/C Failure
Launch failure
SwartwoutReliability of University-Class Spacecraft
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*
What Doesn’t Break?• Structures• Thermal*• Commercial
Electronics in Radiation Environment*
32 of 120 orbited spacecraft “failed”
Perhaps we should worry more about system-level functional testing and less (?) about the space environment…
Lifetimereduction
SwartwoutReliability of University-Class Spacecraft
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Independent
Flagship
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
SwartwoutReliability of University-Class Spacecraft
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)
– Build CubeSats and, if sustained, it’s a series of E-class CubeSats
SwartwoutReliability of University-Class Spacecraft
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Repeat Independents
Singleton Independents
Repeat Flags
Singleton Flags
Repeat Business: Encouraging Trends!
Flagship Schools• 29 schools built 67 spacecraft
(47%)• 8 schools built 46 spacecraft• 5 have graduatedIndependent 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
SwartwoutReliability of University-Class Spacecraft
Beyond the Beep?
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Science
Technology Demo
Communications
No External Payload
SwartwoutReliability of University-Class Spacecraft
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)
SwartwoutReliability of University-Class Spacecraft
Here Come the CubeSats (and Friends)
85 CubeSats in 12 years79 in the “CubeSat Era” (2003-
now)30 Manifested for 2012
(or is it 50?)
2012
SwartwoutReliability of University-Class Spacecraft
Not as International as You’d Think (yet)
SwartwoutReliability of University-Class Spacecraft
CubeSat by Developer
SwartwoutReliability of University-Class Spacecraft
Beepsat = No Mission (except beeping)
SwartwoutReliability of University-Class Spacecraft
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!
SwartwoutReliability of University-Class Spacecraft
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-Workshop
Cape Canaveral, FL22 March 2012
SwartwoutReliability of University-Class Spacecraft
It’s Not Just CubeSats! [Okay, it’s mostly CubeSats]
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Manifested >40 kg
Manifested 10-40 kg
Manifested < 10 kg