Uv lunar observatory ana gomez castro

GOMEZ DE CASTRO GFE - ILOA - 2020 0
LUNAR UV OBSERVATORIES
THE CHALLENGES AND THE REWARDS
Prof. Ana I Gómez de Castro, JCUVA-AEGORA/Universidad Complutense de Madrid, Spain

THE MOON HAS NO ATMOSPHERE
ONLY PROBLEMS:
- Micrometeorites impact
(10-20 kTons/yr on the Lunar surface or
0.5 mg/m2/yrat <10 km/s>, mass: 0.1-10-6
mg)
- VERY EXPENSIVE !!!
WHY AN ULTRAVIOLET OBSERVATORY FROM THE MOON?
The resonance transitions of the most abundant species in Universe
The electronic transitions of the most abundant molecules
are in the Ultraviolet
Earth’s atmosphere blocks UV radiation forcing
UV astronomy to be Space astronomy

POTENTIAL SCIENCE FROM UV LUNAR OBSERVATORIES
INTERGALACTIC MEDIUM,
CHEMICAL EVOLUTION & STAR FORMATION FORMATION OF PLANETARY SYSTEMS

POTENTIAL SCIENCE FROM UV LUNAR OBSERVATORIES
EXOPLANETS EXOSPHERE’S AND PLANETARY WINDS
Figure 2: (a) synthetic spectra illustrating pO2-dependent absorption
by the O2-A band as a function of pO2. The UV O3 band is much mor
may also produce abiotic O2/O3 through the efficient
(Wordsworth & Pierrehumbert 2014). We do not dwell
because we acknowledge that single band ozone detect
insufficient information to claim a certain detection o
signature on a habitable zone exoplanet in the solar neig
compelling case for follow-up observations. Multiple dete
DETECTION OF BIOSIGNATURES
Figure 1: A schematic history of oxygen on Earth from Schwieterman et al. 2018b
0.1% PAL
doi:10.1038/nature14501
ud of hydrogen escaping the
xoplanet GJ 436b
Alain Lecavelier des Etangs3,4
, Guillaume He´brard3,4,5
, Ste´phane Udry1
,
, David K. Sing9
& Alfred Vidal-Madjar3,4
e frac-
ion1–6
.
, lead-
gun as
heres;
ilable.
t spec-
e star,
in the
et the
436b)
optical
ut two
proxi-
ferent
meris).
d by a
ms. We
ms per
e of a
would
, were
visit 2)
maging
ST). A
10 (ref.
rposes.
aneous
agged,
t over
m s21
, HI).
he star
it lasts
being
mission
rted in
ted by
giant
planet
(see Methods). Large variations are detected over a part of the
Lyman-a line at times corresponding to the optical transit, which
cannot be explained by any known instrumental effects. The most
notable absorption occurs in the blue wing of the line for radial
velocities between 2120 km s21
to 240 km s21
, ,2 h before the
optical mid-transit time (‘pre-transit’), during the optical transit
(‘in-transit’) and ,1 h after the optical mid-transit time and beyond
(‘post-transit’) in the three visits (Fig. 1 and Extended Data Fig. 1).
In-transit, over half the stellar disk (56.2 6 3.6%, 1s) is eclipsed
(Fig. 2a). This is far deeper than any ultraviolet transits of hot
Jupiters and significantly (,9s) deeper than the 22.9 6 3.9% (1s)
post-transit signal previously reported in visit 1 data6
. The ultraviolet
transit also starts much earlier (,2.7 h) than claimed previously; the
difference is mainly due to our finding of a pre-transit absorption
and updated transit ephemeris (see Methods). Visit 0 data17
acquired
,3 years before visit 1 and ,30h after transit show that the out-of-
transitvariabilityissmallcomparedwiththeblue-shiftedsignature.This
gives us confidence that the true out-of-transit baseline is measured in
–200 –100 0 100 200
Velocity (km s–1)
1,215.0 1,215.5 1,216.0 1,216.5
Wavelength (Å)
12
10
8
6
4
2
0
Flux(×10–14ergcm–2s–1Å–1)
–2
Figure 1 | Evolution of the hydrogen Lyman-a emission line of GJ 436. The
line has been averaged over out-of-transit (black), pre-transit (blue), in-transit
(green) and post-transit (red) observations from individual spectra (see
Extended Data Fig. 1). The 1s uncertainties have been propagated accordingly
from the errors calculated by the STIS data reduction pipeline. The line profile

AND OBSERVATION OF THE EARTH AS AN EXOPLANET
a=384,748 km, e= 0.05
Bow shock: 90,000 km
Magnetotail: 6,300,000 km
Earth aurora UV (POLAR/UVI) –
OI and FUV continuum (140-190 nm)
Earth’s exosphere from the LAICA instrument
in the PROCYON microspacecraft, JAXA

The Moon offers a stable dynamical anchorage and a vantage point for
observation of the Earth-Space interface at exospheric and magnetospheric scale
Energetic Neutral Atom (ENA) Observation
Image of the Earth magnetosphere at 30.4 nm (He II) obtained with
the EUV camera on Chang'e 3 [Source: Chinese Academy of Sciences].
OBSERVATION
THEORY

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
0
100
200
300
-2.5log(F/F0
)(mmag)
Proxima Cen
0 1 2 3 4 5 6
0
5
10
15
-2.5log(F/F0
)(mmag)
AU Mic
0 5 10 15
Time (h)
0
2
4
6
-2.5log(F/F0
)(mmag)
Sun - α Cen
Lyman – α predicted light curves
Theroretical light curves according
to the noise model and
observational configuration
described in
Gómez de Castro et al. 2018.
(no ISM absorption is considered)
SNR(Proxima Cen) = 11.7 obtained
with a 4 m telescope and time
binning of the photon counts of 2
minutes.
SNR(AU Mic) = 3.5 obtained with a
12 m telescope and time binning 4
minutes.
SNR(αCen) = 4.4 obtained with a 12
m telescope and time binning 10
minutes.
Gómez de Castro et al. 2018
… PROVIDING IMPORTANT CLUES FOR EXOPLANETARY INVESTIGATION

EarthASAP, an example
• Production of the first 3D map of the Earth exosphere from outside by
monitoring the Earth Lyα emission… fundamental data for exo-Earth research.
• Study the interaction between the Earth magnetosphere and the interplanetary
medium/solar wind.
• Monitoring geomagnetic phenomena on large scales through ENA with HeII.
• Systematic survey of the heliosphere in Lyα, investigating the distribution of
diffuse matter within the heliosphere and the IBEX ribbon.
• Monitoring of the water content and the space weather in the Moon poles
Gómez de Castro et al. 2019, JATIS
Ana I. Gómez de Castro, Leire Beitia-Antero, Carlos E. Miravet-Fuster, L. Tarabini,
Albert Tomás, Juan Carlos Vallejo, Ada Canet, Mikhail Sachkov, Shingo Kameda

• Lunar orbiter at 500 km above the surface in a
low eccentricity polar orbit. The orbital period is
2.64 hours. Orbital plane always contains the
Moon rotation axis and the center of the Earth.
• For each orbital period, a basic cycle will be
implemented consisting in surveying:
• 64 minutes the Earth exosphere,
• 12 minutes the South pole of the Moon,
• 64 minutes the heliosphere,
• 12 minutes the North pole of the Moon.
EarthASAP: the mission

LUNAR Science:
rocks hydration and dust clouds levitation mechanisms
Hendrix et al 2016

Monitoring the Heliosphere, minor bodies, comets
IBEX ribbon
Schwandron et al. 2014 Heliospheric Lyα emission from SOHO/SWAM
Kountrounpa et al. 2017
EarthASAP is designed to
grow on the experience
of SOHO/SWAN providing
higher angular resolution
(0.05o instead of 1o) and a
wide field of view to study
comets photoevaporation
process and the interaction
of the coma with the
heliospheric magnetic field.

• a UV telescope integrated inside a 8U cubesat
• to map the Earth’s exosphere and magnetosphere, the
heliosphere and the Lunar poles with a wide field imager
having a field of view of 20o × 30o with an angular resolution
of 3 arcmin.
• Detector: solar-blind MCP
• Filters set:
• Narrow band: Lyα, O I, CI, and He II lines.
• Broad band 115-175nm results directly from MCP solar
blind detector.
• BaF2 long pass filter. This filter prevents that photons
with wavelengths below 140 nm reach the detector; by
comparing the images obtained with this filter with those
obtained with the naked detector the reddening of the
radiation can be derived. If variations are detected, they
could indicate the presence of dust clouds (for instance
dust clouds levitating on the Lunar surface).
EarthASAP: the payload

Simulation of Earth image as seen with the design

Technological Challenges
1. Electronics & Systems for deep space.
2. Deployment in lunar orbit.
3. Navigation systems.
4. Communications.
Star tracker and on-board computer
Hyperion Technologies
Battery and telemetry unit
GOMSpace, Innovative solutions in Space
Ion thrusters for cubesat

• Data will be 4.2 MB images of 1024×1024 pixels
that will be pre-processed in orbit before being
transferred to the Lunar relay. On-board pre-
processing will include:
• subtraction of background parasite signal produce by
cosmic rays
• geometric correction of the data taking into account
the detector distortions and the variations in
projection angle.
• Protocols will be implemented to detect and
track transient events such as solar flares
reaching the Earth, solar storms and geo-
storms.
EarthASAP: data management
EarthASAP data relay Lunar Orbiter visibility

EarthASAP: some cubesat technology elements
8U cubesat structure
Innovative solutions in Space
4U for navigation components
Star tracker, reaction wheels and on-board computer
Hyperion Technologies
Solar panels, battery and telemetry unit
GOMSpace, Innovative solutions in Space

TO SUMMARIZE
vLunar observatories provide a unique opportunity
for UV astronomy
vThe Moon provides an advantageous location to
observe the Earth’s magnetosphere, exosphere and
direct interaction with the Solar Wind. The Moon
may become the baseline for Space weather
observatories.
vObservation of the Earth from the Moon provides
realistic data for the programs intended to detect
exo-Earths
vA simple mission such as EarthASAP could provide
crucial information for larger missions (i.e.
exoplanetary research) at a VERY LOW cost (20
Meuro versus 1.000 Meuro), increasing significantly
the scientific return
vA landed UV telescope within the ILOA will provide
data for a much longer time span.
GOMEZ DE CASTRO 17

Uv lunar observatory ana gomez castro

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