Science Requirements Flowdown : Impacts on the Capabilities of Small* Satellites

1. Science Requirements Flowdown : Impacts on the Capabilities of Small* Satellites * ~1-30 kg David Klumpar Montana State UniversitySpace Science and Engineering Laboratory May 16, 2007

2. Three Messages • Impact of Requirements flowdown • Nanosats (1-30 kg) have “taken off” • CubeSats (1-3 kg): An introduction and a potential role in space weather science and in training the next generation workforce NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

3. Who, What, Where, When?….Lots of questions Cost? Complexity? Mission Requirements Science Requirements Engineering Requirements Mass? Size? NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

4. This satellite is just small enough to allow its sensor to see the distant universe Q: What is the appropriate size for a satellite A: No larger than necessary This satellite is just big enough to allow its sensor to measurethe radiation belts

5. This satellite carries a 6 g energetic particle sensor: It - masses 1 kg - generates 1.5 w O.A. - size is 10 cm - passive magnetic ACS - TM rate 1200 bps This satellite carries a 1.5 kg energetic particle sensor suite: It - masses 30 kg - generates 8 w O.A. - size is 47 cm - active magnetic ACS - TM rate 9600 bps NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

6. Mission/Science Requirements that drive the S/C Bus • Power --> are body mount solar arrays sufficient? … articulated extensible arrays are major cost driver • Attitude Control: is active 3-axis pointing required? • Attitude Determination --> Pointing knowledge • Transceiver link margin/Telemetry Rate Chose the simplest instruments and concept of operations that close the mission requirement. NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

7. Historical Trends: Nanosatellite (<20 kg) Launch Log 1990-1999: 14 2000-2006: 50 Four Nanosatellites scheduled for launch 12/06 on STS-116 and Minotaur NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

8. Specific Recent Nanosat Sciencecraft -1 ST-5 3 x 25 kg (US) Technologyvalidation and geospace science (2006) Quakesat 4.5 kg (US) -- ULF Earthquake Precursor signals (2003) FalconSat-2 19.5 kg (US A.F. Academy): Ionospheric plasma (2006-FTO) Munin (Sweden) 5.5 kg AuroralPhysics (2000) NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

9. Specific Recent Nanosat Sciencecraft -2 GeneSat-1 -- 4 kg NASA-AmesBiological sciences investigation (12/2006) SNAP-1 (UK) 6.5 kg Surrey Satellite Technologies. Demonstrated rendezvous and formation flying (2000). NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

10. CubeSat-101 The CubeSat ICD NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

11. “1U” 10 cm 30 cm “3U” What is a CubeSat? • The basic 1U CubeSat (rules of thumb): • 10x10x10 cm cube • Mass < 1 kg • Power: about 2 w orbit avg • Available payload volume: 300-500 cm3 • 1U, 2U, 3U constitute present systems with space heritage (P-Pod launch deployer) “2U” NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

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15. Baikonur Cosmodrome Delivery to Launch - 15 days July 9, 2006 July 12, 2006 July 26, 2006 NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

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17. Specific Recent CubeSat-class Sciencecraft July 2006 Cluster Launch: A single rocket carrying 18 satellites (unrelated) was to place payloads in LEO. Fourteen were nanosatellites from 1 - 2 kg each. Four of these were ScienceCraft nanosatellites built by U.S. universities.MEROPE -- 1 kg Trapped Radiation Variations(2006-FTO)MONTANA STATE UNIVERSITYION -- 2 kg Mesospheric Airglow (2006-FTO)UNIVERSITY OF ILLINOISIce Cube (-1, -2) 1 kg ea Ionospheric Scintillations (2006-FTO)CORNELL NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

18. CubeSats Rule!!??? • NO !! Definitely not appropriate for most missions. • Why not? • Limited resources • Power • Volume • Telemetry • Yet the concept has legs: • - Small carriers for small low-power, simple sensors • Deployed as an array as space weather monitors • Non-intrusive launch as secondary payloads • And…. It is a model that is scalable NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

19. Space Weather System Concept Approach: Large numbers of small low-cost satellites will make simultaneous coordinated multi-point measurements throughout appropriately-sized regions of Geospace carrying thoughtfully selected operational-grade instruments. Hypothesis: Nanosatellite technologies are sufficiently advanced to enable low-cost, low-mass constellation class satellites carrying operational instruments for space weather. Enablers: Advances in microelectronics, microthrusters, MEMs sensor devices, low-power electronics, high-efficiency solar cells, & microminiaturization have enabled satellites with mass fractions of 80-90% (payload mass/total mass) leading to the concept of: The “ScienceCraft”: An instrument(s) containing the satellite rather than a satellite bus carrying instruments. NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

20. Characteristics of an Operational Space Wx System-1 • The concept model has the following characteristics: • the recognition that operational space weather data will be provided from a distributed array of autonomous measuring stations many of which will be in space (with the largest number in LEO) • the stations are designed for, and built in, a production environment • the unit cost of the hardware is minimized by: • employing relatively simple sensors (sufficient to meet the measurement requirements with no unnecessary frills) • limiting the sensor complement to those that provide only the essential measurements • single string, simple support system for the sensors (i.e., the s/c bus) NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

21. Characteristics of an Operational Space Wx System-2 • the lifetime system costs overall are minimized by: • designing the system to be tolerant of unit failures • using the aforementioned production run philosophy on the hardware component • automating data flow from sensor-to-enduser (minimizing operations manpower) • launch costs for the LEO assets are minimumized by launching large numbers of stations on two or three single small launch vehicles (cluster launches) Robust system design: Acceptance of risk that some fraction of the individual stations will fail at no impact to system performance NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

22. Summary – Three Messages • Impact of Requirements flowdown • The mission goal sets the science requirements • Science requirements drive the engineering implementation • Nanosats (1-20 kg) have “taken off” • 14 launched 1990-1999 • 50 launched 2000-2006 • Jan-April 2007, setting a new record? • CubeSats (1-3 kg) may have a role • Ease of integration (sats --> dispenser --> launcher) • Low-risk as secondaries (containment, inert at launch) • Flexibility to accommodate on virtually any launcher • Standard interface minimizes NRE • Science -- you decide • IMHO, 70 1 kg nanosats carrying simple sensors deployed simultaneously in LEO make a compelling mission for operational space weather NSF Small Satellite Workshop - May 15-17, 2007 Klumpar