Author Topic: Russian Space Telescopes (Read 28973 times)

websquid · « **on:** 09/07/2013 02:45 pm »

Maybe it makes sense to start a topic on the planned russian space observatories, which are now in several stages of development. There is a whole series under development, based on NPO Lavochkin's "Navigator" satellite bus. The first project out of this series is the Spektr-R/RadioAstron which is already in orbit.

Currently, following projects are part of that series:
Spektr-R: 10m-Space Radio Telescope, used for interferometry to reach maximum angular resolutions ( http://forum.nasaspaceflight.com/index.php?topic=27335.0 ), in orbit since 2011

Spektr-RG: X-Ray survey telescope. The main instrument eROSITA comes from Germany, the smaller ART-XC is built in Russia (parts of it are manufactured at NASA-MSFC). It will provide the first all sky survey since ROSAT in the early 90ies, which much higher energetic and angular resolution (and in a broader range of energies, 0.5-10keV). Launch is planned for first half of 2015 (using a Zenit-3F)

Spektr-UF/World Space Observatory-Ultraviolet: 1.7m-UV telescope. It's construction is similar to Hubble, but it is completely optimized for ultraviolet and will therefore be much more productive and precise than Hubble's UV-instruments. It is created in cooperation with Spain, british company e2v will deliver parts of the spectrographs. Launch is planned for 2016 (Proton-M, upper stage is not yet known)

Gamma-400: This project is best described as a Fermi-successor. It will have better performance at high energies than Fermi and additional ability to detect particles (a bit like AMS does on board of the ISS). This project has a large italian participation. Launch could take place 2019 (but I highly doubt this, Gamma-400 simply is not yet "safe" enough to get proper funding)

Spektr-M/Millimetron: 10m-Far-Infrared/Submillimetre/Millimetre-Telescope. It is intented to work in two modes: Single-Dish-Mode for FIR/Sub-MM observations, using instruments which are roughly based on the european Herschel. In interferometry-mode (sub-mm/mm) it works together with earth-based telescopes like ALMA to work as an interferometer. Because of the L2-Orbit (distance to earth about 1.75 million km) it could reach angular resolutions of up to 40nano-arcseconds at 0.3mm wavelength. In comparison, RadioAstron reaches up to 7 micro-arcseconds. Compared with Hubble, the resolution is about 1 million times better, but obviously at other wavelengths.

(I will post additional information about those project here, stay tuned

)

websquid · « **Reply #1 on:** 09/07/2013 03:11 pm »

Spektr-RG

The satellite consists mainly of three parts: The satellite bus Navigator and the X-Ray Telescopes eROSITA and ART-XC

Both telescopes are in fact a combination auf 7 identical modules. eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the larger one, developed for energies ranging from 0.2-10keV. Its sensitivity is better than Chandra as a comparison, but it can not reach the same resolution (it is still by far better than ROSAT was). It has a 1°x1° field of view.

ART-XC (Astronomical Roentgen Telescope - X-ray Concentrator) is the smaller of the telescopes and has only a 0.5°x0.5° FOV and also a worse resolution compared to eROSITA. But it works in the range of 6-30keV and therefore is used for the higher-energetic x-rays. The combination of both telescopes will result in an extremely detailed broad-band all sky survey.

It will be launched to the L2 - a similar orbit like Herschel, Planck and so on...
In survey mode the satellite will slowly spin around itself, so that it scans the sky in large circle (6 hours for one spin). This means that it lasts 6 months to scan the complete sky. Because of this observation mode the equatorial areas of the sky get the least observation time, the poles get the most (eROSITA deep field north/south).

It is planned to make 8 all sky surveys in the first 4 years of operation. Repeated surveys increase the observation time. So weaker objects are detectable, which can not be detected confidentially in one survey, as well as transient objects can be observed (for example tidal disruption events).

After completion of the surveys, Spektr-RG shall be used for pointed observations for at least 3 years (which means it has a design life-time of about 7.5 years - some months to reach the operational orbit and test the instruments, 4 years survey, 3 years pointed observations)

At the moment, the german MPE and the russian IKI work on the flight models of eROSITA and ART-XC (they will be delivered at the beginning of next year to NPO Lavochkin). Lavochkin itself does work at the X-Band scientific communication system at the moment. Despite of these 3 (admittedly large

) parts, the service module is already complete and is currently undergoing tests.

http://www.mpe.mpg.de/eROSITA
http://hea.iki.rssi.ru/SRG/en/index.php

EE Scott · « **Reply #2 on:** 09/07/2013 08:22 pm »

Thanks for this information. Looks very promising!

websquid · « **Reply #3 on:** 09/07/2013 08:43 pm »

Quote from: EE Scott on 09/07/2013 08:22 pm

Thanks for this information.

No problem. And now the next part

Spektr-UF/WSO-UV

What is it? Simply said, it's the "Russian Hubble". It looks similar and has a similar concept, but is slightly smaller (1.7m-mirror) and limited to ultraviolet light (110-320nm). The telescope itself is called T-170M and developed by NPO Lavochkin (NPOL also . It will have to instrument units - the ISSIS camera for imaging and the WUVS spectrograph suite, containing three different spectrographs with different resolutions (up to R~100,000).

While ISSIS is created in Spain (Madrid University), WUVS is designed in Russia (INASAN/FIAN), but a large contract was awarded to the english company e2v just a few days ago ( http://www.e2v.com/news/e2v-signs-multi-million-pound-contract-with-the-russian-academy-of-sciences-for-the-supply-of-an-imaging-sub-system-for-the-world-space-observatory---ultraviolet/ )

It may be smaller as hubble and limited to a much smaller wavelength range, but this means it can be largely optimised for this task (especially optical coatings). Therefore it's sensitivity and resolution are even better than Hubble's UV-instruments (mainly COS/STIS).

The launch is currently planned for 2016, using a Proton rocket. Spektr-UF will be placed in a 51.8° inclined geosynchronos orbit, visible from Spain and Russia (both countries will have a ground segment to control the spacecraft). It will be in fact Hubble's successor in the UV-range, which isn't visible through the atmosphere. Spektr-UF is therefore important for the whole scientific community worldwide. The project team intends to use the telescope as open as possible for every scientist in the world - this explains the second name "World Space Observatory - Ultraviolet"

At the moment Lavochkin works mostly at the T-170M flight model. Prototypes of the instruments are also built, the working flight models are under construction or planned, it looks know like every necessary contract was awarded. I don't know about the current state of the Navigator service module, but this should not be a large problem, because it is in fact a serial product - it looks like Spektr-UF will be the 7th satellite based on this platform. (following Spektr-R, -RG, Elektro-L1/2/3 and Arktika-M1)

http://wso.inasan.ru/index.html
http://www.wso-uv.es/index.php/
http://www.laspace.ru/rus/spektrUF.php

websquid · « **Reply #4 on:** 09/07/2013 09:26 pm »

Gamma-400

While Spektr-RG and Spektr-UF are actually built now, Gamma-400 and Spektr-M are mostly concepts at the moment. So keep in mind, that these may not be final parameters of the project

Gamma-400 is intented to be a successor to Fermi. Because the construction concept is similar, it may be useful to compare the (currently planned) parameters of both spacecrafts:

	Fermi-LAT	Gamma-400
Orbit	560km	500-300000 km (initial) / ~100000km (final)
Energy range	0.1-300GeV	0.1-10000GeV
Sensitivity area	1.8m²	0.5m²
Coordinate detectors	Si strips with pitch 0.23 mm	Si strips with pitch 0.1 mm
Angular resolution (Eγ > 100 GeV)	~0.1°	~0.01°
Calorimeter (thickness, r.l.)	CsI (8.5)	BGO + CsI(Tl) + Si strips (~25)
Energy resolution (Eγ > 10 GeV)	~10%	~1%

Some remarks:
-Effective area depends on the energy. Fermi may have a larger effective area for a small range of energies, but the area(energy) function of Gamma-400 will be much "flatter" and that is the reason, why Gamma-400 can detect gamma rays at much higher energies.
-calorimeter thickness is a value which defines how much energy the gamma-ray loses while travelling through the calorimeter. 1 "ray length" (r.l.) is the way on which the gamma-ray energy is reduced to a fraction 1/e of its initial value.

In general, if you compare Fermi and Gamma-400 it is obvious, that the Gamma-400 team concentrates on extremely high precision. This is especially useful for the search for dark matter. If there are certain spectral lines because of dark matter annihilation (like it could exist around 140GeV) the high energy resolution allows to determine this feature with high precision and therefore needs significantly less amount of detected gamma-rays for statistically proved detections.

Launch of Gamma-400 could take place in 2019 (on a Proton or Angara launch vehicle), but this depends on the amount of funding this project will receive in the next years.

http://gamma400.lebedev.ru/indexeng.html

websquid · « **Reply #5 on:** 09/07/2013 10:06 pm »

Spektr-M/Millimetron

What is it?
Herschel on steroids
RadioAstron on steroids
JWST on steroids

All in one

Like I already said, it will work from far-infrared (0.02mm) until millimeter (20mm) wavelengths. Smaller wavelengths in single-dish-mode with instruments derived from Herschel (Bolometer array, heterodyne receivers/spectrometers). At longer wavelengths (starting with 0.3mm) it will use VLBI-receiveres derived from ALMA and Spektr-R. This means it can be used as a two-element interferometer with extremely precise linear resolution - ideal to measure sizes of several structures in the universe. Maybe even direct measurements of supermassive black hole sizes (and derived from size, their masses).

But why JWST on steroids? Because it has a similar construction concept...
The 10m-mirror, made of a central 3m-dish and 24 petals is inherited from Spektr-R. But what makes Spektr-M unique is its sophisticated and ambitious cryotechnology. The complete telescope and instrument compartment is surrounded by 5 layers of thermal insulation. 4 layers are passive heat-shields, cooling down the whole telescope to 20K - similar to the JWST concept. But Spektr-M is much more advanced. It has active coolers, which cool down the telescope to about 4K. This massively reduces thermal noise and increases the sensitivity of the instruments. For some wavelengths, the single 10m-Spektr-M will have the same sensitivity as the complete ALMA array (64x 12m-dish) combined!

The lifetime of the 6.6t heavy spacecraft (about the same as JWST) shall be 10 years. The lifetime of the cryocoolers is only expected as 3-5 years, but the passive cooling is enough for very good results - but excellent need of course the best cooling possible

Obviously this project is extremely complicated and the biggest problem is, to create such light-weight structures to realize it. Consequently most of the preliminary development work on this project was materials science. Prototypes of critical components are manufactured and the team now can slowly move to implement the project. Launch is estimated at the beginning of the 2020s.

The project team is led by ASC FIAN - the same institute which runs Spektr-R/RadioAstron at the moment. After launch of Spektr-R most of their development team moved to Spektr-M. Leading industrial partner is NPO Lavochkin, providing the Navigator-M service module (the standard Navigator simply is too small for this mission and needs to be improved) and system integration. ISS Reshetnev will create the telescope and instrument compartment. They just signed the roadmap for the next 3 years with ASC representatives. Another important partner is SRON (Netherlands), which will develop and coordinate some of the instruments.

http://asc-lebedev.ru/index2.php?engdep=20
http://www.sron.rug.nl/millimetron/MillimetronWorkshopGroningen2013 (interesting PDFs!)
http://www.laspace.ru/rus/mill.php

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So that's it. A small overview of all large observatories which are currently part of the russian space program. If there are news about them I will post them, but feel free to ask if there are open questions, I think I could answer some of them

websquid · « **Reply #6 on:** 09/11/2013 11:46 am »

Short News about Spektr-UF: The secondary mirror just got its reflective coating (Al+MgF2)

Responsible for this work is ukrainian company SIA Luch. Earlier this year they also coated the primary mirror (same facility, nice size comparison between primary/secondary mirror

)

kevin-rf · « **Reply #7 on:** 09/11/2013 07:19 pm »

Looks like it is still inside the coating chamber. The poles most likely contain(ed) witness samples, you can still see them taped around the secondary. The copper pot on the right I think is for Al, while the two copper pots in the center are most likely for a protective overcoat (Silicon Oxide or something special). I think we are seeing a two door chamber and not a reflection off the back wall.

Very shiny chamber, I like how clean the chamber is. The Al coating chambers I have seen are often lined with foil so they are easier to clean.

Very nice, thanks for sharing.

kevin-rf · « **Reply #8 on:** 09/11/2013 07:21 pm »

I take that back, it looks like the witness samples are inside of the primary mirrors hole. Clever

websquid · « **Reply #9 on:** 10/23/2013 03:55 pm »

Sad update about Spektr-RG..
https://wiki.mpe.mpg.de/eRosita/erosita_consortium_meeting_oct2013
There is a massive delay, caused by the german eROSITA telescope. A launch next year is clearly impossible, Spektr-RG slips to the end of 2015 - at least, maybe (so we almost can say that for sure) 2016.