1© The Aerospace Corporation, 2021

Space Scientific Instrument

Taxonomy (SSIT)

version 2.0

Nichols F. Brown

The Aerospace Corporation

2021 NASA Cost and Schedule Symposium

April 14, 2021

Approved for public release. OTR 2021-00458.

2

IntroductionSpace Scientific Instrument Taxonomy (SSIT)

Taxonomy to create a more uniform language for space instruments

Goal is to spread SSIT acceptance/use

• A scheme of classification, a taxonomy, intended to foster a common language

when classifying and describing space instruments

– developed to support tools and databases used in assessments for NASA SMD

– provides a basis for a relatively uniform and understood nomenclature

– simplifies cross-referencing and analogy selection for cost/schedule estimates

• Intended to be

– universal

• encompasses all space instrument types (historical or near future)

• provides greater detail and broader scope than previous instrument classifications

– compatible with other space instrument taxonomies

• aligns with verbiage and how experts think of the instruments they work with

• maps with cost models developed by multiple organizations (e.g. NICM, SICM)

• Version 2.0

• updated based on space community feedback to the initial SSIT released in 2018

• incorporates feedback received from cost/space community

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InspirationZoological Taxonomy

Lesson:

Taxonomies are not fixed and are refined over time

• The science of defining and classifying

biological organisms based on shared

characteristics

– Believe It or Not! - formerly the term “worm” or

“fish” could have been applied to the same animal

• Long history

– Some trace taxonomy back to Aristotle

– Modern taxonomy; Carolus Linnaeus (1735)

– Many iterations since

Source: © Encyclopedia Britannica 2018, https://www.britannica.com/topic/Homo-sapiens

Source: Wikipedia, https://en.wikipedia.org/wiki/Taxonomy_(biology)

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Space Scientific Instrument Taxonomy (SSIT)Organization of SSIT version 2.0

• Instruments are classified in a three-level hierarchy

– first based on phenomena being studied/measured

– then on similarity; stressing traits affecting an instrument’s complexity & cost/schedule

– each lower-level category is a subset of the one above

• Full taxonomy – 53 categories at lowest level available

– included support elements for practicality as still want data for cost estimates

– each category given an outline number for fast referencing

We will not be reviewing the whole taxonomy!!

1.1 Electric Field 4.1 Passive Optical 6.1 Scan Platform

1.1.1 Double Probe 4.1.1 Cryo-Cooled Passive Optical 6.2 Deployment Mechanism

1.1.2 Electron Drift 4.1.2 Optical Telescope Assembly 6.3 Robotic Arm

1.2 Magnetometer 4.1.3 Radiometer 6.4 Data Processing Unit

1.2.1 Fluxgate 4.1.4 Pyrheliometer 6.5 Cryogenic Systems

1.2.2. Search Coil 4.1.5 Film Camera 6.5.1 Cryogenic Radiator

1.2.3 Ionized Gas Vapor 4.1.6 Interferometer 6.5.2 Expendable Cryogen Cooler

1.2.4 Magnetoresistive 4.1.7 Single-Band Imager 6.5.3 Mechanical Cryocooler

2.1 Mass Spectrometer 4.1.8 Natural Color Imager 6.6 Accelerometer

2.1.1 Quadrupole MS 4.1.9 Multi-Spectral Imager/Spectrometer 6.7 Ultra Stable Oscillator

2.1.2 Time-of-Flight MS 4.1.10 Hyper-Spectral Imager/Spectrometer 6.8 Mirror Target

2.1.3 Sector Field MS 4.2 Active Optical 6.9 Positioning Receivers

2.1.4 Ion Cyclotron Resonance MS 4.2.1 Laser Ranging 7.1 Entry and Descent Sensor

2.2 Charge and X-ray Detector 4.2.2 Laser Velocimeter / Vibrometer 7.2 Meteorological Station

2.2.1 High Energy Particle Detector 4.2.3 Laser Imager 7.3 Sample Collector

2.2.2 Low Energy Particle Detector 4.2.4 Laser Scatterometer 7.4 Sample Analyzer

2.3 Plasma Instrument 5.1 Passive MW/RF 7.5 Seismographer

2.3.1 Plasma Probe 5.2 Active MW/RF 8.1 MW/RF Communications

2.3.2 Retarding Potential Analyzer 5.2.1 MW/RF Ranging 8.2 Laser Communications

2.3.3 Ion Drift Meter 5.2.2 MW/RF Imager 9 Other2.4 Dust Detector 5.2.3 MW/RF Scatterometer

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SSIT vs. SSIT version 2.0Listening to the Industry

Tapping into a broad set of expertise to

create greater community consensus

• Reorganization suggested by Joe

Mrozinski at JPL

– remove Flight vs. In-situ as the top

level of hierarchy

• Solicited industry feedback

– 2018 NASA Cost & Sch. Symposium

– Aerospace Corp. Workshop Series

– 2019 IEEE Aerospace Conference

• Space Community was Pro-Reorg

– Avoids repeated categories

• e.g. optical in both flight & in-situ

– Flight vs. In-situ instruments do tend

to be different; physics is the same

• Similar designs have similar

complexities irrelevant of location

1.1. Electric Field

1.1.1 Double Probe

1.1.2 Electron Drift

1.2. Magnetometer

1.2.1 Fluxgate

1.2.2. Search Coil

1.2.3 Ionized Gas Vapor

1.2.4 Magnetoresistive

2.1 Mass Spectrometer

2.1.1 Quadrupole MS

2.1.2 Time-of-Flight MS

2.1.3 Sector Field MS

2.1.4 Ion Cyclotron Resonance MS

2.2. Charge and X-ray Detector

2.2.1 High Energy Particle Detector

2.2.2 Low Energy Particle Detector

2.3. Plasma Instrument

2.3.1 Plasma Probe

2.3.2 Retarding Potential Analyzer

2.3.3 Ion Drift Meter

2.4. Dust Detector

3. XRT4.1. Passive Optical

4.1.1 Cryo-cooled Passive Optical

4.1.2 Optical Telescope Assembly

4.1.3 Radiometer

4.1.4 Pyrheliometer

4.1.5 Film Camera

4.1.6 Interferometer

4.1.7 Single-band Imager

4.1.8 Natural Color Imager

4.1.9 Multi-spectral Imager/Spectrometer

4.1.10 Hyper-spectral Imager/Spectrometer

4.2. Active Optical

4.2.1 Laser Ranging

4.2.2 Laser Velocimeter / Vibrometer

4.2.3 Laser Imager

4.2.4 Laser Scatterometer

5.1. Passive MW/RF

5.2. Active MW/RF

5.2.1 MW/RF Ranging

5.2.2 MW/RF Imager

5.2.3 MW/RF Scatterometer

6.1 Scan Platform

6.2 Deployment Mechanism

6.3 Robotic Arm

6.4 Data Processing Unit

6.5 Cryogenic Systems

6.5.1 Cryogenic Radiator

6.5.2 Expendable Cryogen Cooler

6.5.3 Mechanical Cryocooler

6.6 Accelerometer

6.7 Ultra Stable Oscillator

6.8 Mirror Target

6.9 Positioning Receivers

7.1 Entry and Descent Sensor

7.2 Meterological Station

7.3 Sample Collector

7.4 Sample Analyzer

7.5 Seismographer

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1.1. Electric Field

1.1.1 Double Probe

1.1.2 Electron Drift

1.2. Magnetometer

1.2.1 Fluxgate

1.2.2. Search Coil

1.2.3 Ionized Gas Vapor

1.2.4 Magnetoresistive

2.1 Mass Spectrometer

2.1.1 Quadrupole MS

2.1.2 Time-of-Flight MS

2.1.3 Sector Field MS

2.1.4 Ion Cyclotron Resonance MS

2.2. Charge and X-ray Detector

2.2.1 High Energy Particle Detector

2.2.2 Low Energy Particle Detector

2.3. Plasma Instrument

2.3.1 Plasma Probe

2.3.2 Retarding Potential Analyzer

2.3.3 Ion Drift Meter

2.4. Dust Detector

3. XRT4.1. Passive Optical

4.1.1 Cryo-cooled Passive Optical

4.1.2 Optical Telescope Assembly

4.1.3 Radiometer

4.1.4 Pyrheliometer

4.1.5 Film Camera

4.1.6 Interferometer

4.1.7 Single-band Imager

4.1.8 Natural Color Imager

4.1.9 Multi-spectral Imager/Spectrometer

4.1.10 Hyper-spectral Imager/Spectrometer

4.2. Active Optical

4.2.1 Laser Ranging

4.2.2 Laser Velocimeter / Vibrometer

4.2.3 Laser Imager

4.2.4 Laser Scatterometer

5.1. Passive MW/RF

5.2. Active MW/RF

5.2.1 MW/RF Ranging

5.2.2 MW/RF Imager

5.2.3 MW/RF Scatterometer

6.1 Scan Platform

6.2 Deployment Mechanism

6.3 Data Processing Unit

6.4 Cryogenic Systems

6.4.1 Cryogenic Radiator

6.4.2 Expendable Cryogen Cooler

6.4.3 Mechanical Cryocooler

6.5 Accelerometer

6.6 Ultra Stable Oscillator

6.7 Mirror Target

6.8 Positioning Receivers

7.1 Entry and Descent Sensor

7.2 Meterological Station

7.3 Arm/Boom

7.4 Sample Collector/Processor

7.5 Sample Analyzer

7.6 Passive Optical

7.7 Active Optical

7.8 Passive MW/RF

7.9 Active MW/RF

7.10 Seismographer

7.11 Mirror Target

7.12 Positioning Receivers

8.1 MW/RF Communications

8.2 Laser Communications

9. Other

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Version 2.0

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Space Scientific Instrument Taxonomy (SSIT)Documentation

SSIT documentation is authorized for public release and unlimited distribution

• Free electronic copies available

– download by NASA users through the One NASA Cost Engineering (ONCE) database

– by contacting Nick Brown (nichols.f.brown@aero.org)

• Full documentation available

– authorized for public release and unlimited distribution

– definition of basic instrument classification terms

– description for each category

• written to be understood by a general user with a

scientific or engineering background

• no need for in-depth expert knowledge or jargon

– examples of the types of instruments and

measurements typically associated with that category

– aliases or other common names for the same category

– decision trees to aid a user to determine category

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SSIT DocumentationExample Definition

Examples of typical

instruments & units

measured aid in

determination if your

instrument fits in category

Attempted to use most

commonly used term for

each category based on

literature search & SME

consultations. Aliases

listed help for determining

that two items are the

same by different names

Descriptions use simple,

concise language. Goal is

for anyone with a science

or engineering background

to be able to understand

Outlined documentation to

allow shorthand

referencing

8

SSIT DocumentationHelpful Materials

Glossary, diagrams, and decision trees are provided to aid common understanding;

particularly when we want to clarify boundaries between categories

9

ConclusionSpace Scientific Instrument Taxonomy (SSIT)

THANK YOU

• Space Scientific Instrument Taxonomy (SSIT) is a scheme of classification

providing structure for communicating the components, traits, and

commonalities among space science instruments (a.k.a. space payloads)

– Intended to foster a common language for space instruments

• Version 2.0 represents a collaborative effort ready for broader application

– Reorganized based on consultations with space scientific instrument experts from

across the industry – Thanks to all who contributed!

– Full documentation available and releasable to the public

• downloadable by NASA users through the ONCE database

• by contacting Nick Brown (nichols.f.brown@aero.org)

– NASA adoption has started with NICM and CADRe

• SSIT is intended to be an open collaboration that is improved, edited, and

reedited over time based on industry feedback

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Back-up

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Author Bio / Contact Information

Nichols Brownnichols.f.brown@aero.org

Mr. Brown is a cost/schedule analyst and systems engineer in the

Programmatic Assessments & Center of Excellence Department at The

Aerospace Corporation.

He first joined The Aerospace Corporation as an intern and became full-time

employee in 2006 working at the Space Architecture Department and then in

the Integrated Cost & Schedule Analysis Department where he was involved

in a wide range of space system and architecture analyses including systems

engineering, design, and programmatic assessments for civil and military

programs.

Prior to joining the Aerospace Corporation, Mr. Brown spent two years at

Northrop Grumman Mission Systems where he was part of their Future

Technical Leaders Program and was involved in intelligence community

programs, NPOESS and GPS.

Mr. Brown holds a BS in Aerospace Engineering from Boston University and

an MS in Aerospace Engineering from the Georgia Institute of Technology.