NSF Small Satellite Workshop - May 15-17,2007 Science Requirements Flowdown : Impacts on the Capabilities of Small* Satellites David Klumpar Montana State University Space Science and Engineering Laboratory May 16, 2007 * ~1-30 kg

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

NSF Small Satellite Workshop - May 15-17,2007 Q: What is the appropriate size for a satellite A: No larger than necessary This satellite is just small enough to allow its sensor to see the distant universe This satellite is just big enough to allow its sensor to measure the radiation belts

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

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

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

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

NSF Small Satellite Workshop - May 15-17, 2007 Klumpar 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: cm 3 1U, 2U, 3U constitute present systems with space heritage (P-Pod launch deployer) “2U” “3U” 30 cm “1U” 10 cm

NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

Delivery to Launch - 15 days July 9, 2006 Baikonur Cosmodrome July 12, 2006 July 26, 2006

NSF Small Satellite Workshop - May 15-17, 2007 Klumpar

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

NSF Small Satellite Workshop - May 15-17, 2007 Klumpar 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 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 % (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 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 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 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 –50 launched –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