Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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First flyby of a pristine comet

PI: Tilak Hewagama

Lead Institution: University of Maryland

PSDS3 meeting – LPSC – March 18, 2018

Primitive Object Volatile Explorer (PrOVE) – Waypoints and Opportunistic Deep Space 

Missions to Comets
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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• A new or long period comet flyby will 

yield unprecedented science. 

- New comet missions: limited time 

to develop/launch a spacecraft after 

discovery.

- Periodic comet missions: potentially 

involves mission risk with launch 

platform delays.

• Solution: Waypoints in space. 

• CubeSats/SmallSats are a cost efficient 

pathway for parking a spacecraft 

pending a new comet.

• PrOVE payload goal is to acquire 8-m 

spatial resolution images of nucleus, 

volatile inventory and temperatures of a 

new or periodic comet. 

Primitive Object Volatile Explorer (PrOVE) – Waypoints and Opportunistic Deep Space 

Missions to Comets
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Background

Compact 2-12 μm camera

Morehead State Univ

bus

ersity 6U 

History:

UMD/GSFC/MSU/CUA/JPL team proposed Primitive Object Volatile 

Explorer (PrOVE) to the SIMPLEx-1 program. 

• Mission was to a volatile rich Jupiter-family comet 46P/Wirtanen

with an ecliptic plane crossing within 0.09 AU of Earth.

• Launch platform delays were an identified risk.

• Spacecraft and Propulsion were not investigated for more

remote missions.

PSDS3 award allowed the opportunity 

to: 

• Study waypoints

• Investigate Cruise and Ops for highinclination, high-energy new 

comets

• Spacecraft systems 

Identify Waypoints

Solution:

• Retire risk associated 

with launch platform 

delays – investigate 

Waypoints in space.

• Change science scope 

to observing a new 

comet
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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York University

M. Daly

INO (Canada)

Infrared Multispectral Camera

(Volatiles & Thermal)

University of Maryland

T. Hewagama (PI) 

J. Bauer

L. Feaga 

J. Sunshine

T. Livengood

GSFC

S. Aslam

D. Folta

T. Hurford

M. Mumma

C. Nixon

G. Villanueva

Catholic University of America

N. Gorius

Morehead State University

B. Malphrus

A. Zucherman

JPL

P. Clark

Subsystems

Management

Science - Volatiles

Science – Imaging

Science - Thermal

Payload 1 - Infrared Camera

Payload 2 - Visible Camera

Spacecraft

Systems

Radiation

Thermal

Navigation

Communications

Data, PDS

MSSS 

Visible Camera

PrOVE Partners
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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 Are among the most enigmatic and spectacular objects in the sky

 indelibly recorded throughout human history

 Formed at the beginning of the 

Solar System (4.6 billion years ago)

 record conditions, compositional variability,

and processes in the protoplanetary disk

 preserve record of volatiles in the 

early solar nebula

 building blocks of the planets

 bearers of volatiles to inner solar system

 “Stored” in outer Solar System freezer

 relatively unchanged since formation

 Contain dust, organics, and ices 

 contribute ingredients for life to Earth

 Potentially hazardous to life on Earth

Why Study Comets?

Bayeux Tapestry: Battle Hastings 1066

Comet Lovejoy, Dec 2011

Image Credit: HST Comet Team & NASA

Shoemaker-Levy 9, 1994

When beggars die, there are no comets seen....

Calpurnia in Shakespeare’s Julius Caesar
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Types of Comets

• Short period (Jupiter-family)

– Orbit between Jupiter and the Sun

– Disturbed by the gravity of the planets

– Spacecraft have imaged 5

• Halley type (every 50-200 years)

– Orbit between Pluto and the Sun

– Spacecraft have imaged 1

• Long period (>> 200 years)

– “New” and “young” come from the Oort 

cloud when disturbed by a passing star

– None observed up close

67P/C-G

(Rosetta)

5 km

These are the only 

cometary nuclei that 

we have images of.

Potential for high science return
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Why Waypoints

New comets:

Hale-Bopp discovery was 2 years prior to perihelion.

Many long-period comets are discovered with even shorter times. 

Proposed solution:

Park a spacecraft in space. 

Statistics of Oort cloud comets:

Statistics over past 10 years indicate 1 detected every 2 years. Hughes (2001) estimates the historical long-period 

comet flux as ~1 per year. 

Close flyby to study nucleus of a long-period comet:

Surface maps of ~8-m resolution and volatile inventory will yield compelling scientific results. 

Insufficient lead time 

for a mission

Technology advances in CubeSats/SmallSats enable 

cost-efficient opportunities

Spacecraft lifetime of ~4 years

CubeSat/SmallSat missions can risk close flyby 

operations

The PSDS3 effort showed that a mission to a new comet is 

within contemporary CubeSat/SmallSat technology!
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Mission Concept and Science Deliverables

Science Objectives:

PrOVE will perform a close flyby of a new or Jupiter-family comet

e

d

y

w

h

y

near perihelion when surface processes and volatile activity ar

maximum, to probe the origin of the nucleus and the formation an

evolution of our Solar System.

• Investigate morphological and chemical heterogeneity of nucleus b

quantifying surface fine structure and volatile species abundances, and ho

these depend on solar insolation;

• Map surface relief and spatial distribution of volatiles, especially CO2 (whic

cannot be measured from ground based telescopes), and determine an

variations;

• Determine the frequency and distribution of outbursts.

CHNOPS
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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nd Life

Science Objectives Investigations Measurement Products Result Requirements

SO1 Determine Measure dayside Surface Maps of the Surface relief and 

Determine surface surface fine surface reflected surface thermal models of 

st a

morphology and structure and reflectance at broadband topography and comet response 

thermal structure thermophysical high spatial visible at <8-m temperature in to insolation and 

 Plane

properties of the resolution, and pixel resolution the inner coma its relationship to 

Blocks for

near nucleus thermal inertia and thermal active outburst 

inner coma of the inner emission regions 

coma measured from 

observations of 7-10 μm and 8-

surface thermal 14 μm 

n Buildi g

emission

SO2 Determine the Determine the Maps of the Inner coma maps Information about 

as

Determine the distribution of relative comet nucleus of compositions the relative 

coma chemical volatiles within abundances of and coma at of CO2. CO, abundances of 

s Bodie

composition, and the coma CO2, CO, various spatial organics and H2O CO2, CO, organics 

variations in the organics and resolutions and H2O within 

ve

spatial distribution H2O within the the target 

of CO2, CO, and coma and active 

Primiti

organics with outbursts

respect to H2O

of 

SO3 Map the comet’s Maps of the Maps of the Maps of the Information on 

Role 

Determine the coma region to comet’s coma comet coma comet nucleus the number of 

frequency and detect locations region regions and coma at outburst events 

Understand the 

distribution of and number of allowing the various spatial observed and the 

outburst as outburst events ejected resolutions source locations 

measured by local material to be for this events 

enhancements and detected from the comet 

the endogenic nucleus 

mechanism that 

drives these events

Science Traceability Matrix
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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PrOVE can address Priority Comet Science!

Ideal Criteria:

Flyby of a dynamically new (Oort cloud) or long period comet. Identify a waypoint/parking orbit in space, 

launch from an arbitrary platform and disposal above Earth’s gravity well, navigate to waypoint with onboard propulsion, indefinite residence with minimal station keeping, design a cruise trajectory to a newly 

acquired target or a known long period comet, navigate to a new target with on-board propulsion, flyby 

encounter with 5m optimum spatial resolution (visible imaging).

Minimum Criteria:

Flyby of a Jupiter Family comet and Near-Earth comet (q<1.3 AU, P<200 years). 

SKG: https://www.nasa.gov/exploration/library/skg.html

SBAG report on venues/contexts for addressing SKGs “Space-based robotic missions which can be 

telescopic or precursor mission to a small body target” includes high priority for NEO albedos, size, 

rotation state, dust environment, resource identification. 
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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• Low inclination comet apparition

Comet ID Inclination Perihelion passage (ET) Orbit Class

C/2017 T1 (Heinze) 96.96 2018-Feb-21.5 PAR

C/2015 E61-B(PANSTARR) 6.35 2017-May-09.9 HYP

C/2017 E1 (Borisov) 14.55 2017-Apr-10.1 HYP

C/2016 U1 (NEOWISE) 46.43 2017-Jan-14.0 HYP

C/2013 X1 (PANSTARRS) 163.23 2016-Apr-20.7 HYP

C/2013 US10 (Catalina) 148.88 2015-Nov-15.7 HYP

C/2015 G2 (MASTER) 147.56 2015-May-23.8 HYP

C/2013 A1 (SidingSpri) 129.03 2014-Oct-25.2 HYP

C/2012 K1 (PANSTARRS) 142.43 2014-Aug-27.7 HYP

C/2014 C2 (STEREO) 135.5 2014-Feb-18.2 PAR

C/2012 S1 (ISON) 62.4 2013-Nov-28.8 HYP

C/2012 T5 (Bressi) 72.1 2013-Feb-24.1 HYP

C/2011 U3 (PANSTARRS) 116.78 2012-Jun-03.9 HYP

C/2012 E2 (SWAN) 144.24 2012-Mar-15.0 PAR

C/2012 C2 (Bruenjes) 162.79 2012-Mar-12.6 HYP

C/2011 Q2 (McNaught) 36.87 2012-Jan-19.8 HYP

C/2010 X1 (Elenin) 1.84 2011-Sep-10.7 HYP

C/2011 M1 (LINEAR) 70.18 2011-Sep-07.6 HYP

C/2009 R1 (McNaught) 77.03 2010-Jul-02.7 HYP

C/2010 J4 (WISE) 162.3 2010-May-03.2 PAR

C/2008 T2 (Cardinal) 56.3 2009-Jun-13.2 HYP

C/2009 G1 (STEREO) 108.32 2009-Apr-16.6 PAR

C/2008 A1 (McNaught) 82.55 2008-Sep-29.1 HYP

C/2007 W1 (Boattini) 9.89 2008-Jun-24.9 HYP

C/2008 J4 (McNaught) 87.37 2008-Jun-19.1 HYP

C/2007 F1 (LONEOS) 116.08 2007-Oct-28.8 HYP

C/2006 VZ13 (LINEAR) 134.79 2007-Aug-10.9 HYP

C/2007 P1 (McNaught) 119.21 2007-Apr-03.2 PAR

interval ~2.5 years

Recent Comets listed on JPL/SBDB as Hyperbolic/Parabolic 

H/P comets close to Earth

• 28 in 10 years, MOID<0.6 AU

• 21 in 10 years, MOID<0.4 AU

• ~2 comets/year

High perihelion velocity is 

important!

• Can we reach high-inclination 

comets?
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Waypoint examples examined in PSDS3

Sun-Earth 

Libration 

orbit

Other 

Libration orbit 

examples

Sun-Earth L1/L2 are good solutions

Station keeping is minimal
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Payloads

Infrared Imager/radiometer Visible Imager

ComCAM: IR microbolometer (with TEC) 

has broad spectral response (1-100 μm) 

which includes science requirements of 2-

5 μm for molecular species and 8-12 μm 

for thermal. 

• 384x288 pixels

•IFOV = 120 m @300 km

• 1.2 kg, 2.5 W

VisCAM: High spatial resolution mapping of 

a Jupiter-family comet surface is optimum. 

Mapping of a new comet would be 

unprecedented. 

• 2592x1944 pixels

•IFOV= 8 m @ 300 km

• 0.4 kg, -30C<Toper<40C

• 2.5 W imaging, 1.3 W idle

Based on 

TAGCAMS 

instrument on 

OSIRIS—Rex +

Compact 2-12 μm camera
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Spacecraft Concept

ABC/ESPA Bus Assembly

Stowed volume ~100-U

Low mass

PSDS3 study at Wallops Flight Facility, including GSFC engineers
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Conclusions

• Methodology has the best chance to produce 

ground breaking science by visiting a new comet

• Mission is within current technological 

capabilities

• Spacecraft bus: ~100 U

• Developed ConOps for operations at comet

• Mission time ~4 years from waypoint residency 

to data telemetry
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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Thank you!

We gratefully acknowledge

• Support of the PSDS3 program

• NASA Goddard Space Flight Center • 

NASA Wallops Flight Facility
Planetary Science Deep Space SmallSat Studies (PSDS3) 

Primitive Object Volatile Explorer (PrOVE)

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