1. Millimetron mision sensitivities and instrumentation concept
A.M. Baryshev, W. Wild, G. Goltsman, N.S. Kardashev
Netherlands Institute for Space Research, Netherlands Astro Space Center, Lebedev Physical Institute, Russia

2. Outline Main concept of “Millimetron” mission
Concept 12 m diameter deployable antenna of “Millimetron”
Astronomical instruments
Sensitivities
Conclusions
ISSTT 2008, Groningen

3. Telescopes for Radio-astronomy Space Missions
Main requirements and trends
Driven by scientific objective
Telescope size, diameter
Better sensitivity for compact sources ~D2
Better spatial resolution ~D-1
The larger the better
Mirror accuracy
Tendency to observe frequencies, inaccessible from ground
RF > 1 THz
Telescope cooling
Background radiation ~T4
Space environment allow for passive (50 K) and active cooling
4 K dish is highly desired
Large deployable apertures are needed
Ultimate mission: a free flying interferometer with large cold telescopes (>6) FIRI
There are practicalities…
ISSTT 2008, Groningen

4. Millimetron mission parameters and status
Frequency range: from mm wave to THz frequencies
Two observing modes
Space earth VLBI
Single dish mode
Heterodyne and direct detection instruments (arrays)
Aperture diameter 12 meters
~4 m diameter central solid dish (goal 5 µm surface, 4 THz)
12 m petal type deployable (goal 10 µm RMS surface, 1..2 THz)
Passively cooled, K (study active cooling possibilities)
Mass < 4000 kg
Orbit similar to Radioastron km apogee or L2
Approved mission in Russia (Included in 10 year plan of RSA)
Now in conceptual phase, launch frame ~
ISSTT 2008, Groningen

5. Spacecraft concept Three layer deployable thermal shields
Deployable primary mirror
Cold focal plane instruments (0.1…4 K)
Deployable truss
“Navigator” spacecraft platform
ISSTT 2008, Groningen

6. Space platform Navigator
Lavochkin association
ISSTT 2008, Groningen

7. Antenna optical parameters
Cassegrain scheme
Diameter 12 m
Secondary focus
Moveable secondary mirror
Active main dish (concept) including laser petal position measurements and feed abck system
ISSTT 2008, Groningen

8. Radiosatron antenna construction (folded)
Proton-M
Launcher
ISSTT 2008, Groningen

9. Details opening
ISSTT 2008, Groningen

10. Antenna deployment concept
Two 20:1 scale models are being made
ISSTT 2008, Groningen

11. Deploying sequence
ISSTT 2008, Groningen

12. Astronomical instruments
Large format low spectral resolution camera (polarization sensitive)
Medium spectral resolution (R= ) imaging spectrometer (similar to SPICA SAFARI)
High resolution spectrometer (similar to Herschel HIFI instrument)
SVLBI instruments (heterodyne, covering ALMA bands)
ISSTT 2008, Groningen

13. Low resolution spectrometer
1mm mm wavelength, several channels
State of the art sensitivity
Up to 10 kPixels for the shorter wavelength channel
Use 12m diameter aperture up to 0.15 mm
Possibility to use central mirror for shorter wavelengths
Specifically do not mention technologies
NEP 10^-19 required depending on the achieved antenna temperature
Cooling mK
ISSTT 2008, Groningen

14. Photometer (SPIRE)
ISSTT 2008, Groningen

15. Sensitivity of photometer, 12m dish, 50K
ISSTT 2008, Groningen

16. Photometer sensitivity 4m central dish, 50 K
ISSTT 2008, Groningen

17. Photometer sensitivity
ISSTT 2008, Groningen

18. 4K dish temperature (for reference)
ISSTT 2008, Groningen

19. Medium resolution spectrometer
1mm mm wavelength, several channels
State of the art sensitivity
Up to 5 kPixels for the shorter wavelength channel
Use 12m diameter aperture up to 0.15 mm
Possibility to use central mirror for shorter wavelengths
R= (frequency dependent)
Technology TBD
NEP 10^-19 required depending on the achieved antenna temperature
Cooling 100…300mK
ISSTT 2008, Groningen

20. FTS (SPIRE)
ISSTT 2008, Groningen

21. Sensitivity of medium resolution spectrometer
ISSTT 2008, Groningen

22. Sensitivity of medium resolution spectrometer
ISSTT 2008, Groningen

23. Sensitivity of medium resolution spectrometer
ISSTT 2008, Groningen

24. 4K dish for reference
ISSTT 2008, Groningen

25. High resolution spectrometer
Spot or continuous frequency bands THz for 12m aperture
Spot frequency bands up to 5 THz using central solid dish
Small focal plane arrays for lower frequencies (LO power limited)
IF 4-12 GHz
Polarization !!!
Conceptually based on Herschel HIFI instrument
Cooling 4 K
ISSTT 2008, Groningen

26. Herschel HIFI
ISSTT 2008, Groningen

27. Example of frequency distribution
Millimetron Single-dish instrumentation
Instrument
Frequency (GHz) or wavelength
Ang. res. ()
Spectral res.
Detector technology
Sensitivity
TRL
Heterodyne receivers
HET-1
480 – 700
8…12
 106
SIS 2x2 mixer array with multiplier LO
Tsys < 100 K 6
1100 – 1400
5…6
Tsys < 200 K
HET-2
1650 – 2000 ~3
HEB mixers with multiplier or QCL LO
Tsys < 500 K
2600 – 2700
~2.5
Tsys < 700 K 4
4700 – 4800
4 (1)
Tsys < 1000 K
Far-Infrared imaging photometer/spectrometer
M-PACS
60 – 210 m
 4
few 103 spectrom.
Photoconductor arrays
2 x Wm-2
ISSTT 2008, Groningen

28. Sensitivities
ISSTT 2008, Groningen

29. SVLBI instruments R > 10000
Selected ALMA bands THz for 12m aperture
Spot frequency bands up to 5 THz using central solid dish
On board data recorder
On board stable reference
Fast data link
IF 4-12 GHz (compatible to ALMA)
Can be conceptually based on Herschel HIFI instrument
Cooling 4 K
ISSTT 2008, Groningen

30. SIS mixers, multiplier chain LO, dual pol.
Instrument type
VLBI receiver
Heterodyne receivers
covering ALMA bands
Receiver
VLBI-1
ALMA-1
ALMA-3
ALMA-6
ALMA-9
Frequency range
18 – 26 GHz
GHz
GHz
GHz
GHz
Detector technology
HEMT amplifier
SIS mixers, multiplier chain LO, dual pol.
Or HEMT
Sensitivity Tsys
< 40 K
< 17 K SSB
< 37К SSB
< 90 K SSB
< 150 K DSB
TRL 6
ISSTT 2008, Groningen