Planetary Probes: When it Has to be In-Situ Anthony Colaprete NASA Ames Research Center 10 th Annual International Planetary Probe Workshop June 17, 2013 Planetary Probes: When Less is More

What is a Planetary Probe? Planetary “probes” come in all shapes and sizes: Atmospheric entry probes, landers, rovers, orbiters, balloons, airplanes Common feature: in-situ Some questions required measurements that are in-situ Potentially limiting the total data and/or the “breadth” of observation Often very complex (read: “expensive”) to get “a lot” on an in-situ probe They have to compete with a perception that more is better A missions duration or number of terabytes often used as measure of intrinsic value Sometimes more data is better, e.g., increasing SNR, more complete spatial or temporal coverage, etc. All against a backdrop of dwindling opportunities and resources

Examples of when in-situ measurements are unique and critical Atmospheres Concentrations of key species, e.g., Nobel gasses Ratios of stable isotopes, e.g., those in the Martian (MAVEN and Curiosity), Venus, Titan and in the Saturn atmosphere Dynamics, e.g, atmospheric structure, stability and winds in the Venus, Mars, Titan and Saturn Surface and Subsurface Specific elemental composition at small scales Soil/regolith processing for composition or other parameter Micro-scale morphologies Sub-surface access; volatiles, environment (thermal state) Geophysical parameters: seismometery and geotechnical measures

How do we adapt our thinking of planetary probes to changing resource profiles? To be acceptable (i.e., selected) in-situ probes must align with: Be more affordable – Both monetarily and in terms of engineering metrics (mass, power, etc.) Use new techniques, designs, and architectures – Make them applicable to a range of parent architectures; take advantage of multitude of launch opportunities Unique and critical measurements – Worth the headache of not making the measurement remotely

From D. Bearden, The Aerospace Corporation KISS Keep the Science Focused

Once the focused goals are set….stay disciplined!

The key science objectives that would be addressed by a Saturn Probe mission include: – Origin and Evolution – Saturn atmospheric elemental ratios relative to hydrogen (C, S, N, O, He, Ne, Ar, Kr, Xe) and key isotopic ratios (e.g., D/H, 15N/14N, 3He/4He and other noble gas isotopes), He relative to solar, Jupiter. – Planetary Processes – Global circulation, dynamics, meteorology. Winds (Doppler and cloud track), interior processes (by measuring disequilibrium species, such as PH3, CO, AsH3, GeH4, SiH4). [P, C] Ref: Atreya, S. K. et al., (2006) Multiprobe exploration of the giant planets – Shallow probes, Proc. International Planetary Probes Workshop, Anavyssos, Ref: David Atkinson NASA – Cassini: PIA03560: A Gallery of Views of Saturn's Deep Clouds 7 An example of how focusing the science can “enable” a probe mission: Saturn Probes

Probe Size and Data Rate Drive Architecture Data Telecom Antenna Size and Type # and Type of Instruments A high-level view to illustrate how two key parameters drive design to the same conclusion Descent vs Com. Power Size Mass LV Cost # of Probes Galileo-Type Probes 8

An alternate Architecture would start with the most focused payload possible For example, to address the critical questions regarding composition, the most important instruments are: Neutral Mass Spectrometer (NMS) or Gas Chromatograph Mass Spectrometer (GCMS) Atmosphere Structure Instrument (ASI) Accepting just these two measurement/instrument types would approximately halve the data, mass, and power requirements of the payload This assumes no improvements over Galileo instrumentation, which is an incorrect assumption Significant savings can be realized in reduced mass instrumentation, in particular in the area of the NMS/GCMS The lower mass, power and data rate can result in a smaller probe Assuming a payload mass fraction of approximately 10% the probe mass, a kg probe is a reasonable goal Alternate Architectures 9

Example of Alternate Architecture Trade Space Focused Payload Probe Size/Mass Instruments on Probe and Probelet Relay Options Descent Depth Probelet Drop Depth Wind Shear Frequency vs Antenna Reqs. Look Angles Water Constraint Data Rate Structure Measurements A fresh look, beginning with a highly focused measurement set, greatly opens otherwise closed trade space 10

JPL cubesat transponder LMRST antenna NanoSpace MEMS propulsion module Aerojet 1U Champs MIT Space Propulsion Lab/Paulo Lozano Cubesat reaction wheels (Sinclair Interplanetary) NLAS 6U dispenser Shrinking the Probe: Technologies looking for a home? While we can build all sorts of nano-scale probes, are they capable enough to address important questions in a meaningful way? Strengths in their small “footprint”: more opportunities to fly more payloads more often Need to take care to align with the “Unique and critical science”

MicroProbe Examples Microprobes defined here as kg Include cubesat technologies and architectures Concepts floating about include entry vehicles, aero- platforms, landers, rovers, spacecraft (orbiting, flyby, or rendezvous, comm-relay) Payload mass typically 1-10 kg Sufficient to include instrument capable of of critical measurement(s) Newer technologies allow for very capable propulsion These Microprobes have the potential to extend deep-space access to low-cost research One example is the Planetary Hitch Hiker (PHH), a low-cost rideshare platform for exploring Near-Earth Asteroids (NEAs)

Initial mW Generator Fits at the core of the Baseline Science Station Cubesat Compatible Spine (Science Station Baseline) Small entry probes have potential to open up a new means of exploring Mars, Venus, and other planetary bodies with atmospheres With small payloads entry probes can be scaled down considerably (2x-3x scaling) In the low end of the Microprobe size class (~10 kg) with half the mass being for the payload Micro-Entry Probes Examples From Marc Murbach For Example: Mars MET Stations

Commercial Partnerships, COTS Products, and Secondaries Increased commercial access to space is accelerating commercial product lines, everything from components to complete spacecraft Many smaller commercial companies eager to work with NASA or other agencies and larger business to provide or develop instruments, components and systems A few examples: Using commercial product line, partnered with NASA to develop a flight version:  LCROSS Ultraviolet spectrometer done in <9 months  RESOLVE NIR spectrometer, done in <1 year One of the largest financial commitments is the launch vehicle Every kg of lift capacity should be taken advantage of Opportunities for micro-probes LADEE UVS

Closing Thoughts Past Probe Missions: 1978 (PV), 1995 (GL), 2000(DS2), 2004(HUY) With this trend might have expected the next probe mission in ~2012 But what opportunities? Decadal Survey called out Venus and Saturn Probe missions Numerous Discovery class concepts Very competitive, risk adverse Need to be ready with Strong Concepts and New Ideas: Starts with focus, unique science goals  Minimize complexity Take advantage of smaller systems and components Build commercial / government alliances A secondary on every launch!

Thank you!