Unveil Venus’ UV Absorber with CubeS

Mapping Spectrometer

Funded through the NASA Planetary Science

Deep Space Smallsats Program (PSDS3)

V. Cottini (UMD)

S. Aslam (NASA/GSFC)

N. Gorius (CUA)

T. Hewagama (UMD)

L. Glaze (NASA/GSFC)

N. Ignatiev (IKI RAN)

G. Piccioni (INAF‐IAPS)

E. D’Aversa (INAF‐IAPS)

Characterize Venus’ unknown UV absorber(s)

to understand the planet’s radiative and

thermal balance, and its upper clouds

dynamics and chemistry
PI: Valeria Cottini (UMCP, NASA‐GSFC)

Co‐Is: Shahid Aslam (NASA‐GSFC), Nicolas Gorius

(CUA, NASA‐GSFC), Tilak Hewagama (UMCP),

Giuseppe Piccioni (INAF‐IAPS, Italy)

Coll.: Lori Glaze (NASA‐GSFC), Nikolay Ignatiev(IKI RAN, Russia), Emiliano D’Aversa (INAF‐IAPS,

Italy)

Venus’ atmospheric composition, chemistry,dynamics and radiative transfer modeling:Cottini (Cottini et al. 2008, 2009, 2012, 2016),

Piccioni ‐ PI of ESA/VenusExpress VIRTIS instrument,Ignatiev ‐ CoI of ESA/VenusExpress VMC instrument,Hewagama, D’Aversa)

Mission and Instrum

Mission Planning La

the NASA Wallops FInstrument Design 

at Goddard, Aslam, Hewagama, Piccion

Design, fabrication operation of spect

for remote sensingAslam and Gorius

Venus mission formulation stuCottini, Glaze, P

Ignatiev
 ‐

Venus is an ideal target for SmallSats deep space exploration

• ~1/3 of low‐massstars have planetsin the Venus‐zone

(interior to HZ)

Credit: JAXA Akatsuky


–

• Venus is almostfeatureless in the visible

Credit: NASA Mariner 10

• Venus clouds reflect in the

visible most of the incoming

solar radiation (albedo ~75–90%)

• This absorbed energy is theprimary atmospheric engine of

Venus ‐ superrotation

~50% of the solar energy

received by Venus is absorbed in

the UV by a unidentified

absorbers in its top cloud layer

• In the UV dark and b

• Clouds top structure and UV

absorbers nature are key parameters

for understanding Venus’ atmospheric

dynamics and energy balance

We need a V

spectru
Mission Instrument Channel Spectral Ra

Pioneer Venus OUVS 110‐340 nm 

Venus Express VIRTIS (M Visible) 290‐1100 nVenus Express SPICAV (SUV) 110‐310 nm 

Venus Express VMC (UV) 345‐384 nm 

Akatsuki UVI 293‐365 nm HST STIS (low/med Res) 115‐555 nm 

Messenger MASCS VIS 300‐1000 nCUVE Spectrometer 200‐400 nm 

CUVE Imager 320‐570 nm 

Pioneer Venus not high

spectral resolution and noisy

(e.g., Stewart et al, 1979)

VMC on Venus Expressand Akatsuki gave us

amazing data/UVimages, not spectra

Hubble Space Telescope a

spectra (Jessup et al. 201able to acquire many moavoidance requirements. 

limited dataset/spatial c

VenuresoSPIC

Difficult to investigate

the UV absorber from

Earth’s surface due to

strong UV absorptionin Earth’s atmosphere CUVE can provide high resolution UV

spectrum of Venus, with large coverage

and imaging of cloud top structure
Known absorbers:

 SO2 varies from 0.1 to 1 ppm at the cloud top (Barker 1979, Conway et 

Stewart et al. 1979, Esposito et al. 1988, Bertaux et al. 1996 Marcq et a

 SO about 30% of SO2 (Na et al., 1990)

Other candidate species for the observed UV contrast features:

 Sulfur‐bearing species ‐ sulfur Sx, S8, S2O, OSSO – FeCl3 :

• Zasova 1981 proposes 1 % FeCl3 in 80% H2SO4 and Krasnopolsky (1986) fa

Recently:• Petrova, 2018, support ferried chloride through analysis of glory on Venu

• Messenger MASCS found best fit for S2O and OSSO (Perez‐Hoyos et al. 20

• Lab results fit Pioneer Venus data with OSSO (Wu et al. 2018)

• Carlson 2016 suggests cyclo‐octal S8 and polymeric sulfur Sx (>500 nm we 

discriminate it from FeCl3)

Other proposed absorbers: SCl2, Cl2 and many others (C3O2, CH2O, NOHSO4, 

NH3NO2, (NH4)2SO4, (NH4)S2O5, NH4Cl, Cl2, SCl2, HClO4) (e.g., Pollack et al., 19

al., 1981; Toon et al., 1982; Na and Esposito, 1997; Krasnopolsky 2006)
• Belyaev et al. are analyzing SPICAV and VIRTIS UV‐VIS data

• Petrova, E. et al., 2018. Glory on Venus and selection among the unknown 

Icarus, 306, p. 163‐170

• Pérez‐Hoyos, S. et al., 2018. Venus Upper Clouds and the UV Absorber From

MESSENGER/MASCS Observations. JGRE‐ Planets, 123, 1, pp. 145‐162

• Jessup, K.‐L. et al., 2017. Motivations for a Detailed In‐Situ Investigation of 

Absorber. VEXAG. LPI contribution and EPSC 2018.

• Marcq, E. et al., 2017. Reanalysis of the SPICAV‐UV nadir spectra on the da

SO2 , O3 and other UV absorbers. EPSC.

• Various papers of Lymaye of possible microorganism in Venus clouds and U

• Various papers of Berteaux, Petrova, Lee on UV albedo and cloud properti

Venus Express.

• Markiewicz W. et al., 2018. Aerosol properties in the upper clouds of Venu

observations by the Venus Monitoring Camera (Venus Express). Icarus, 299

• Frandsen, B. N. et al., 2016. Identification of OSSO as a near‐UV absorber 

atmosphere. GRL, 43, 21, pp. 11,146‐11,155.

• Markiewicz, W. et al., 2014. Glory on Venus cloud tops and the unknown U

Icarus, 234, p. 200‐203.
UV absor

and UV 

Venus’ 

its clou‐ drives 

radiativ‐ produ

feature‐ Still un

CUVE – Cubesat UV Experiment –on a polar orbit around Venus

Nadir Observation

Sun

UV a

Data Telemetry Push broom mapping

CUVE Payload‐ UV image spectrometer200 – 400 nm, 0.2 nm

spectral resolution‐ UV multispectral imager

320 – 570 nm

UV absorbeand atmos

Abundance 

SO2 and SO 
Imager Footprint@ 150,000 kmSpatial resolution:

5 km

Coverage: 40 deg lat‐lon

Spectro@ 150,0Spatial rCoverag
Nadir UV dayside is mostly solar light back‐scattered by atmospheric cloud particles.

=> information about scattering particles and gases encountered in the atmosphere by the scatteInhomogeneity in spatial and/or vertical distribution of the unknown absorber produces the fam

used also to study the dynamics of the clouds

SO2 mixing ratio present strong variations of orders of magnitude.

Min and max from Belyaev et al. (2017, Icarus 294, 58), and Vandaele et al. (2017, 295). SO ~ 0.2 

SO2 and also SO

bands between200 and 320 nm

Min (green) and max (black),

mean (red) expected SO2 and

SO abundances

CUVE high res image

spectrometer (200 –

400) nm in red

CUVE lower res

multispectral imager(320 – 570) nm in blue
• 1 unique 12U spacecraft

• Can be deployed from Geostationary Transfer Orbit (GTO)

• Other possible rideshare opportunities: LEO missions, Heliophys

New Frontiers

• Flexible launch date

• Spacecraft reach Venus using internal electrical propulsion syste

• At Venus, spacecraft will be placed in high altitude polar orbit

• Spacecraft establishes direct communication with DSN during cr

instrument check‐out, insertion, operations

• Mature TRL: Most component have high TRL (6‐8).

• Mission end: orbital decay into Venus (no planetary protection c
Venus high spectral resolution UV imaging spectroscopy

Broad spectral range (200 ‐ 570 nm) and high spectral resolution (0.2 n

UV spectrum of Venus

• The study of Venus is part of the three major classes of mission de

the 2014 NASA SMD Science Plan – 4.3 Planetary Science Divisio

“Inner planets: Earth’s Moon, Mars and its satellites, Venus, and 

“Explore and observe the objects in the solar system to understan

formed and evolve” or Objective 1.5 of the 2014 NASA Strategic Plan

• A UV investigation is also part of the Decadal Survey and the Venus 

Analysis Group (VEXAG I.b.1‐2, I.c.1‐2).

Nature of the UV Absorbers in its Atmosphere,

Venus Atmospheric Composition, Chemistry, Dynamics and Energy Bal
Acknowledgments:

NASA under the NASA Planetary Science Deep

Space Smallsats Program (PSDS3) supported the

research described in this report.
SCIENCE OBJECTIVES:

1) Nature of the "Unknown” UV‐absorber; 2) Abundances

and distributions of SO2 and SO at and above Venus’s cloud

tops and correlation with the UV absorber; 3) Atmosphericdynamics at the cloud tops, structure of upper clouds and

wind measurements from cloud‐tracking;PAYLOAD DESCRIPTION:Payload includes (2U, 2kg) • 200‐400 nm image spectrometer (0.2 nm res)

• 320‐600 nm multispectral imager (4 nm res)

TEAM MEMBERS/INSTITUTIONS:

Principal Investigator:Valeria Cottini (UMCP)Co‐Investigators:Shahid Aslam (NASA‐GSFC)Nicolas Gorius (CUA)Tilak Hewagama (UMCP)Giuseppe Piccioni (INAF‐IAPS, Italy)

Collaborators:Lori Glaze (NASA‐GSFC)Nikolay Ignatiev (IKI RAN, Russia)Emiliano D’Aversa (INAF‐IAPS, Italy)

MISSION OVERVIEW:Baseline Spacecraft Configuration • CUVE is a 12U high‐altitude orbiter in 

Venus• CUVE is a targeted mission, with a dedic

and a compact spacecraft bus capable of 

independently or as a ride‐share with anotor to a different target, in order to increase 

• It will perform Nadir dayside observations

• Schedule: early‐to‐mid 2020s