Lunar Ultraviolet Cosmic Imager (LUCI) from Indian Institute of Astrophysics by Margarita Safonova

1. Prospect of UV observations
from the Moon: the journey of
LUCI
Margarita Safonova
Joice Mathew, Jayant Murthy, Binu Kumar, Ajin Prakash, Mayuresh
Sarpotdar, Ambily Suresh, Nirmal K, A.G. Sreejith, Noah Brosch, P U Kamath,
S Sriram
Indian Institute of Astrophysics, Bangalore, India.
Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, Austria.
The Wise Observatory and the Dept. of Physics and Astronomy, Tel Aviv University, Israel.
in collaboration with TeamIndus, Axiom Research Labs, Pvt. Ltd.

2. • “Space travel is utter bilge”, claimed Richard van
der Riet Woolley, on assuming the post of British
Astronomer Royal in 1956.
• Voiced on the eve of the Apollo 11 landing:
"from the point of view of astronomical discovery it
[the Moon landing] is not only bilge but a waste of
money" (Woolley 1969).
For every human endeavor, there are always people asking `WHY?’ Why going to
space, when we can observe safely from the ground? Why going to the Moon, when
we can observe cheaper from the near space?” This was then:
And this happening now: the referee of our latest paper on LUCI asked why do we
need to go to the Moon, why can’t we launch on the CubeSat, even on suborbital
flight? I wonder if Apollo astronauts were asked the same questions? I don’t know
what they would reply, but I can answer with two reasons:
1. It is a frontier;
2. We had an opportunity – and it was provided to us by the Team Indus.

3. Google Lunar X Prize
● Space competition organized by X PRIZE, and sponsored by Google, US$30
million for the winner.
● Privately funded space flight teams to be the first to land a privately funded
robotic spacecraft on the Moon.
● Travel 500 meters, and transmit back high-definition video and images.
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Credit: Google X Prize

4. TeamIndus mission
TeamIndus Lunar lander
Orbital profile of TeamIndus Moon mission
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(Credits: TeamIndus)

5. Moon has no dearth of scientific instruments ,
both on the surface and in orbit:
• Luna 1: instruments for studying the gases contained in interplanetary matter and the
corpuscular radiation of the Sun, equipment for measuring the Earth's magnetic field and
detecting the magnetic field of the Moon, if there is one, instruments for studying meteoric
particles, instruments for registering heavy nuclei in primary cosmic radiation, equipment for
registering the intensity of cosmic rays and the variations of this intensity, and for recording
photons in cosmic radiation.
• Luna 2: September 14, 1959: similar, plus scintillation counters, geiger counters, a
magnetometer, Cherenkov detectors, and micrometeorite detectors. Showed time variations
in the electron flux and energy spectrum in the Van Allen radiation belt.
• Luna 3: 7 Oct 1959: micrometeroid and cosmic ray detectors, first views of the far side of the
Moon.
• Luna 9: 3 February 1966: The radiation detector, the only scientific instrument on board,
measured a dosage of 30 millirads per day. The mission also determined that a spacecraft
would not sink into the lunar dust; that the ground could support a lander. Television camera
rotating mirror system provided a panoramic view of the nearby lunar surface.
• Luna 10: The lunar satellite instruments were able to measure the electrical, magnetic and
radiation fields in near-lunar space.
• Apollo missions of 1969-1972… Chandrayaan, etc…
However, they were all aimed at studying the
Moon/interplanetary space itself, rather than using it a basis
for space observations.

6. • No atmospheric related problems like opacity, thermal
conductivity, wind, seeing.
• Observations can be made continuously if you shield
telescope from the Sun, at least for 14 Earth days
• Lunar surface and low gravity offer a stable platform
• Slow sky rotation give long exposure time
• LEO is easier accessible for repairs
• Going to LEO is cheaper
• Radiation environment more benign
• Dust and micrometeorites
Pluses and minuses
The only telescope ever
repaired in space was Hubble
Doesn’t stop us from
sending deep space
telescopes: L1, L2, Spitzer,
RadioAstron, …
However, the ambitions were always for the large lunar telescopic
installations with 4-100 m mirrors, or total mass of 10-30 tons of radio
antennas, driven possibly by the fact that since we are going to the Moon
anyway, we can as well make it big!
All the Lunar Ranging
Retroreflectors, including
Lunokhod 2’s (1973!), are
still functioning on some
level.

7. http://www.sciencecartoonsplus.com/gallery/einstein/ein07.gif
Sidney Harris

8. UV from the Moon
• First astronomical UV observations from the Moon Apollo
16 team in 1972. 3” Schmidt telescope with FUV
camera/spectrograph. A total of 178 frames of film were
recorded on a film cartridge and returned to Earth for
analysis. Could see stars as faint as V magnitude 11.
• LUT - robotic 15-centimeter R-C NUV telescope with two
hyperbolic mirrors. Magnitude limit: AB 13.5
2017 news: it is the only science instrument on the lander
that is still operational, and could do that for 30 years more.

9. Science cases for the lunar UV telescope
● No atmosphere - transparent to UV
● Very small sidereal rate ~ 0.53’’/s (15”/s on Earth)
● Long integration time
● Transients: SNe, Novae, TDEs
● Variable stars, RRly
● Detection of NEO and PHA
● Hot stellar distribution in the Galactic disk
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Objects Amplitude Timescale
Binaries with compact objects > 1 magnitude several seconds to days
SNe, Novae 0.1-2 magnitude several days
TDEs 0.1-1 magnitude several months
M-Dwarf flares > 1 magnitude seconds to hours
Variable stars 0.1-1 magnitude minutes to 1 day
Sagiv et al. 2014

10. LUCI first incarnation -- Lunar FUV telescope
Aperture 30 cm
Optical design Ritchey-
Chrétien
Focal length 630 mm
FOV 30
Wavelength
range
130-180 nm
Detector XS anode MCP
Resolution 5’’
Power < 10 W
Weight 7.5 kg
Table: Specifications
Structural layout
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11. First LUCI incarnation – FUV telescope

12. Design constraints and considerations on the
instrument
• Weight should not be more than 1.3 kg
- Aperture diameter is limited
- Detector choice is limited
• Dimensions maximum values: 50 cm x 20 cm (L x D)
- Focal Length
• No moving parts associated with the instrument
- single pointing
It is the design concept that defined the science goals
• Observation in NUV wavelength band: 200-320 nm
• Imager: To study bright UV objects (limiting mag 12 AB)
• Transit telescope
• Incorporate mechanical constraints (weight & dimension)
• Availability of components (detector & optics)
• Space qualification requirements
• Time-bound development
• Low cost
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13. Instrument Overview
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Instrument Specifications
Telescope Cassegrain (All Spherical)
Field of View 0.46° x 0.34°
Aperture 8 cm
Focal length 80.69 cm
Detector UV-sensitive CCD
Sensor format 1360x1024 (HxW)
Pixel Scale 1.2”/pixel
Resolution 5”
Band of operation 200—320 nm
Weight ~1.2 kg
Dimension 45 cm x 15 cm (LxD)
Power < 5 W
Sun Avoidance angle 45°
Limiting Magnitude 12 with S/N: 3
LUCI cross section
Although all current UV space missions adopt an R-C telescope
design due to its compactness, one of the main concerns is
the aspheric optics which makes the optical system complex,
expensive and challenging for manufacturing and alignment.

14. Science Objectives
• Study bright objects (mag < 10) in the near-UV domain.
- OB associations, massive star formation regions and planetary nebulae
• Transients and variability (Cao et al. 2011)
- hot stars: binaries with compact
stars, M Dwarf flaring stars
• 60 square degree sky area can be
covered in one lunar day by LUCI
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LUCI detection limits for flares
Loci of LUCI pointing on a lunar day
Proxima Cen
e Eri
t Ceti

15. Second incarnation: Lunar Ultraviolet Cosmic Imager
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The inclination at 250 is to avoid Sun and horizon glow

16. Optical design and Structural layout
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Optical layout

17. Scattering
In the case of zenith pointing, the Sun is always more than 400 away from the pointing
direction. In case of 250 off-zenith, we are always away from the Sun behind the
structure. Scattering of sunlight from the lunar surface is less of a problem because of the
low albedo of the lunar surface in the UV (at least 3 times < Earth's) and the solar flux in
the UV spectral range is strongly reduced.
Scattering contribution in the instrument from:
- tube surface to the primary mirror
- primary mirror to secondary mirror
- secondary mirror to the detector plane
- baffle surfaces to the detector plane
CFRP telescope tube inside walls, mirror mounts
and baffles are black painted with Aeroglaze Z306
which supresses 95% of incident light.
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LUCI in MGKM lab class 1000 clean
room during ground calibrations

18. ● We employed baffles to prevent:
- light which has bypassed the optical system
- the outside field-of-view light reaching the image plane.
● Minimum baffle size to maximize the effective aperture.
Baffles
Calculated baffle parameters:
Primary baffle
➔ Length: 156.10 mm,
➔ Dia: 22.52 mm
Secondary baffle
➔ Length: 27.33 mm,
➔ Dia: 38.12 mm
Scattered light is suppressed
to the order of 10-14 for a
light source at 450 from the
optical axis of LUCI.
Point source
transmittanc
e (PST)

19. LUCI door mechanism
● HMP wire – high modulus
polyethylene) rope 0.28 mm
● Lid straps – beryllium copper
● CFRP – carbon-fibre reinforced
polymer
● Nichrome wire – NiCr alloy, 0.2 mm
Door open configuration

20. Structural and Modal analysis
To ensure the payload will withstand all launch load and landing vibrations
• Launch Loads: Lateral - 25g in all axes, Longitudinal - 25g in all axes
• Natural frequency of the system should be above 100 Hz
Static Analysis: To estimate the maximum stress experienced at static loads
Dynamic Analysis: To find natural frequency and different modes of the system
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Results:
Payload is able to withstand launch loads up to25g in all axes
Natural frequency is 202 Hz ( >100 Hz)
Mode
Frequency
(Hz)
Mode 1 202.35
Mode 2 275.46
Mode 3 513.45
1st mode 2nd mode 3rd mode

21. Thermal analysis
At night on the Moon, the temperature of a radiatively cooled structure goes down to
60 K; we however are not planning to operate at night because there will be no power.
During the daytime, the subsolar point can reach T ~350 K, with an average of 200 K.
However, thermal stresses in the telescope would be much reduced compared to a
space telescope as the Sun moves slowly on the lunar sky, and the illumination is
more or less uniform across the telescope structure, whereas a space telescope is
subject to a large temperature gradient. The lunar environment is thus strongly
favoured if we can provide suitable shielding.
Thermal analysis
Detector ambient temperature on-board the lander will be
maintained at 23+/-2°C by using an active thermal control
system, which consists of a closed-loop control system with
heaters, optical solar reflectors (OSR) and a thermistor. LUCI
will be covered with MLI to achieve the thermal insulation.

22. Detector and filter for LUCI
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Sensor Sony's ICX407BLA UV-
sensitive CCD
Filter UV Bandpass filter with
transmission 20%
Pixel Size μm 4.65x4.65 (HxW)
Total no. of pixels 1360x1024
Dark Noise 1e-/px/s
Readout Noise 7 e-
Full well capacity 14000 e-
Voltage 5 V
Power Consumption 2.5 W
Specifications

23. Detector electronics and interface
3 PCBS stacked one after other
To generate clocks, read the data, and
perform image processing tasks in real time
• Image Sensor PCB
UV-enhanced CCD Sony ICX 407BLA, timing
generator, power 0.9 W
• Voltage Regulator PCB, Power 0.1 W
• Image Processing FPGA PCB
- FPGA (Field Programmable Gate Array
(Spartan-6: XC6SLX150T), Flash, RAM Memories, Power: 1.5 W
DB-15 serial connector (15 pins) to communicate with the spacecraft bus.
Out of the 15 pins, 10 pins are dedicated for 10-bit data transfer. Two pins
for power supply (5 V, GND). Another two pins to interface thermal sensors
and one pin to communicate with the door opening mechanism.
Maximum data transfer possible from LUCI is 1 Kbps. Only 10x10 px windows
around point sources will be downlinked.
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24. LUCI assembly&calibration: infrastructure
Laboratory
- M.G.K. Menon Space lab (where UVIT payload has been assembled and tested)
- Class 1000 clean room facility
- Storage requirements: CVCM (Collective volatile cindensable materials)< 0.01%,
TML (Total mass loss) < 0.15, temperature range: 20-24°C, RH: ~50%
Sub-assemblies
1. Optical
- PM, SM, corrector lens, filter and detector
2. Mechanical
- Telescope tube, telescope interface flange, spider unit, CCD holder, filter
mount, baffles, CCD cover
Calibration Equipment
- Collimated UV light source, reference flat, flat mirror
- Zygo Interferometer, theodolite, NIST detector
- Mounting flanges, shims, target mount, pinholes, 3D-printed payload mounts
- Optical table
Contamination prevention
• IP cleaning
• Ultrasonic cleaning
• Baking
• Nitrogen PURGING
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25. UV Collimator
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UV Collimator block diagram
UV Collimator set-up
- Newtonian UV telescope built to provide
the collimated light to LUCI entrance
aperture.
- 5 micron pinhole
- Wavelength: 200 - 400 nm

26. Opto-mechanical alignment
Optical axis establishment
Opto-mechanical alignment in class 1000 clean room
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- Theodolite: Coarse alignment
- Zygo interferometer: Fine alignment

27. Opto-mechanical assembly: Interferometric alignment setup
Final optical alignment setup: block diagram
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28. Optical performance
Interferometric fringes after the alignment
EE plot: 80% EE within 4x4 pixels WFE map: 0.053 um
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29. Filter transmission measurement
Spectrophotometer setup
Filter transmission
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30. Effective area measurement
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• Total effective area: 153.41 cm2
• Central wavelength: 243.87 nm
Effective area measurement setup
Effective area plot
Sensitivity plot

31. FOV and plate scale PSF Measurement
● FOV: 27’.55×20’.37
● Plate scale: 1.2’’/pixel
● PSF FWHM: 4x4 pixels
FOV measurement setup
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UV collimator and LUCI kept aligned on the
optical table for PSF measurement
3-D plot of LUCI’s image of the 5 µm
pinhole in the UV collimator focal plane

32. LUCI: final assembly

33. Comparison with recent UV missions
Mission parameter GALEX UVIT LUCI
A (cm2) 1950 880 30.15
No. of pixels 4K×4K 512×512 ∼ 1K ×1K
Pixel scale (arcsec/pix) 1.5 3 ∼1.2
FOV (deg2) 1.1 0.7 0.167
FOV (arcmin) 75 28 27.6x20.4 (Rectangular)
UV bandpass (nm) 40 50 120
λ effective (nm) 151.6 151.4 250
Survey parameter (1/cm3) 3.06×107 1.34×108 1.5x 1010
Brightness limit 10 AB 8 AB 3 AB
Survey parameter — for comparing the ability of UV missions to estimate the UV
background (Henry 1982; Brosch 1999)

34. Why LUCI is unique
● Science: Can observe bright UV sources (brighter than 12 mag).
UVIT, GALEX, and other UV observatories cannot look at bright sources because
their detectors can be damaged
● Weight: lightest UV telescope - 1.2 kg
● Cost: ~22,000 USD
● Dimensions: would fit into a ~3-4U CubeSat platform
● Optics: all-spherical optical components.
No other UV payloads have been reported with an all-spherical optical design for
imaging in the NUV domain and weight below 2 kg.

35. LUCI currently
Engineering model: LUCI on the lunar landerLUCI in the class 1000 clean room at MGKML
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LUCI in storage box with continuous grade 5 nitrogen purge.
MGKM lab class 100 room. Waiting for launch…
OrbitBeyond Brings Together a Consortium for
NASA CLPS RFP. Nov. 13 2018
OrbitBeyond. Inc, a new lunar transportation
company, has entered into the exciting cislunar
market … to bid for the $2.6 Billion NASA
Commercial Lunar Payload Services IDIQ contract.
“Winning the NASA CLPS contract will enable
OrbitBeyond to deliver its first lunar landing
mission as early as 2020.”

36. Payload development
We are continuing with our space instruments development, and
have several small payloads that are ready to fly. We have had
serious discussions about flying them on our limited budget but
have not secured a launch as yet. As launch costs decrease with
the larger number of private players, we hope that we will have an
opportunity to launch shortly. Some of our instruments:
Star Sensor-cum Camera: StarSense
Power: 2.5W
Limiting magnitude : 6 Vmag
Weight: 600 gms
Dimensions: 100x120x150 (mm)
Accuracy : 10”
Micro star sensor designed for CubeSats

37. Building Detectors
S. Ambily, Mayuresh Sarpotdar, Joice Mathew, A. G. Sreejith, K. Nirmal, Ajin Prakash, Margarita
Safonova and Jayant Murthy, Development of Data Acquisition Methods for an FPGA-Based
Photon Counting Detector, Journal of Astronomical Instrumentation 2016.
Intensified CMOS detector with
FPGA-based readout.
● S20 photocathode (200-900 nm).
● Can operate in both centroiding
and direct frame transfer mode
● Maximum full frame rate of 30
fps.
Supports a fast readout rate of
500fps with 315 MHz clock

38. Payload development: WiFi NUV imager
Optical Layout to fit into 6U CubeSat
Structural Layout
We have designed a wide-field UV imager (WiFi) that can be flown on a range of available
platforms, such as high-altitude balloons, CubeSats, and larger space missions (Joice Mathew,
et al. 2018, Experimental Astronomy, doi:10.1007/s10686-018-9575-4)
WiFi assembled
UV imager onto a 6U CubeSat

39. Stabilization and pointing platforms
Design, develop and fabricate our own @ <10 K Rs.
— stabilized Alt-Az mount using servo
motors for continuous observations and
tracking.
K. Nirmal, A. G. Sreejith, Joice Mathew, Mayuresh Sarpotdar, Ambily Suresh, Ajin
Prakash, Margarita Safonova and Jayant Murthy, Pointing system for the balloon-
borne Astronomical Payloads, J. Astron. Telesc. Instrum. Syst. 2(4), 047001
(2016), doi: 10.1117/1.JATIS.2.4.047001.