BioSentinel: Monitoring DNA Damage Beyond Low Earth Orbit on a 6U Nanosatellite

Brian Lewis Systems Engineer NASA Ames Research Center BioSentinel

Mission Goals and Objectives • Conduct life science studies relevant to human exploration – 1st biological study beyond LEO in over 40 years – BioSentinel uses DNA double strand break frequencies to calibrate radiation damage in space – Validate biological radiation damage models in space – Demonstrate “biosentinel” science concept • Design payload with sensors for multiple environments – BioSensor, LET Spectrometer, TID Dosimeter – Secondary payload on Space Launch System (SLS) EM-1 in late 2017 – Instrument on ISS at similar time to EM-1 launch – Ground controls in lab and at radiation beam facilities

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BioSentinel

BioSentinel Science Concept

• Quantify DNA damage from space radiation environment – Space environment cannot be reproduced on earth – Omnidirectional, continuous, low flux with varying particle types – Health risk for humans spending long durations beyond LEO – Radiation flux can spike 1000x during a solar particle event (SPE) • Correlate biologic response with TID and LET data – BioSensor payload uses engineered S. cerevisiae – Measures rate of double strand breaks (DSBs) in DNA – LET spectrometer measures particle energy and count – TID dosimeter measures integrated deposited energy • Yeast assay uses microfluidic arrays to monitor for DSBs – Three strains of S. cerevisiae, two controls and an engineered strain – Wet and activate multiple sets of microwells over mission lifetime – DSB and associated repair enable cell growth and division of the engineered “biosentinel” strain – Activate reserve wells in event of an SPE 3 BioSentinel

Launch Mission Orbit • Freeflyer launched as a BioSentinel secondary payload on EM-1 Orbit – Exploration Mission 1: 1st flight of NASA’s Space Launch System • Final orbit of secondaries to be determined • Will likely be Earth-interior, heliocentric orbit • Far outside the LEOs typically occupied by CubeSats – Range to Earth of 0.73 AU at 18 months A representative orbit that Artist’s rendering – Far outside the protective shield BioSentinel might occupy of the Space of Earth’s magnetosphere Launch System

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Payloads and Data Products • 3 color optical system per

~2x106 ~2x102 well No cells cells/well cells/well • Colorimetric and optical no gamma density assay • 25Gy Pressure, RH and temp Prototype Fluidic Card sensors in payload volume SC medium 50Gy (viability) • Selective downlink of

100Gy spectrometer data • Active monitoring of LET ~180Gy and TID to trigger SPE

no gamma response

LET Spectrometer Chip 25Gy

SC-LEU 50Gy medium

100Gy

~180Gy

3 days at 23°C Teledyne dosimeter Typical LET Spectrometer Frame 5 BioSentinel Spacecraft Design

Transponder Avionics Propulsion System Payload Batteries

Star Tracker PharmaSat carried a microwell and fluidics system similar to that which will be used in Deployable Solar Arrays BioSentinel

• Extend ARC biological nanosats to 6U form factor – Port application-based LADEE flight software to capable, reliable avionics – Support autonomous guidance, navigation, attitude control, and propulsion – Generate sufficient power for transponder over long link distances 6

BioSentinel Electrical Power Propulsion • Deployable solar arrays • Required for detumble after deployment – 31 W generated at end of life • Required for momentum management • 3s2p Li-Ion Battery pack • Evaluating cold gas and electric – 5100 mA-hr capacity propulsion systems

Body Rates 8 x 6 y z

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0 deg/sec -2

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-8 0 50 100 150 200 250 300 350 400 450 500 time (sec)

7 Detumble controller simulation BioSentinel Guidance, Navigation and Control • GNC Functions – Detumble – Pointing for communications, power generation, and safe mode – Autonomous momentum management • 3 axis controlled system – Reaction wheels and star tracker for nominal operations – Sun sensors and inertial measurement unit for contingencies

Angular Attitude Error 70 unfiltered EKF 60

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30 error (arcsec) error 20 GN&C Development Testbed

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0 Simulated Controller Performance 0 5 10 15 20 25 30 8 time (min) BioSentinel Communications • X-Band Coherent Transponder – Command and Telemetry – Ranging and Nav Support Achievable Downlink Data Rate During Mission – 100 – 4000 bps telemetry 9 8 • 20 dB medium-gain antenna and 6 dB 7 low gain antenna 6 6dB link margin • Deep Space Network 34m ground 5 3dB link margin station 4 • 2 – 8 hours aperture time per week 3 2 1

0 Possible Data Rate [kb/s] Rate Data Possible 100 200 300 400 500 600 Mission Elapsed Time (Days)

9 BioSentinel Structures / Thermal • 6U volume nanosatellite Spacecraft Internal Temperatures • BioSensor payload maintained at 1 atm pressure • Payload cold biased to 4 C for yeast viability • Active microfluidic “tile” maintained at 23 °C for growth

Payload Thermal Variability

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BioSentinel (Potential) Firsts and Challenges • 1st NASA biology studies beyond LEO in 4 decades – Enabling comparison across multiple radiation & gravitation environments • 1st 6U CubeSat to fly beyond LEO – Challenges for communications and attitude control – Collaboration with sister missions reduces risk • 1st CubeSat to combine a biology science payload with capable C&DH and FSW – Payload includes autonomous measurement response to SPEs Affiliations : NASA ARC, NASA JSC, NASA GRC, Loma Linda U. Med. Center, Univ. Saskatchewan Support : NASA Human Exploration and Operations Mission Directorate (HEOMD) Advanced Exploration Systems Division – Jitendra Joshi, Jason Crusan Program Execs. 11