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RadioAstron: Mission Support

Jump to: Mission Support Status, Current Tracking Statistics, Mission Support Request

ILRS Mission Support Status:

SLR is very important for RadioAstron since the mission is devoted to study the following astrometric problems:

  • Construction of a high-precision celestial coordinate frame
  • Development of a high precision model of the Earth's gravitational field and testing the theory of General Relativity by means of the precision redshift measurements

Current ILRS Tracking Statistics: (as of 04-Feb-2020 08:00:12)

SatelliteSite NameStationStart DateEnd DateNo. PassesNo. Points
RADIOASTRONGrasse78452011-11-15 01:55:492017-08-20 22:00:44651,920
RADIOASTRONMount Stromlo78252016-09-10 18:40:432016-09-10 18:40:43111
RADIOASTRONWettzell88342016-09-29 19:52:452016-09-29 19:52:45112
RadioAstron ILRS Mission Support Request form (October 19, 2009, PDF)

SECTION I: Mission Information:

General Information:

Satellite Name: SPECTER-R/RadioAstrom
Satellite Host Organization: Lavochkin Association, Russia
Web Address: http://www.laspace.ru

Contact Information:

Primary Technical Contact Information:
Name: Alexander Sheikhet
Address: 141400, Himki City, Moscow Region, Russia, Leningradskaya str., 24 , Lavochkin Association
Phone No.: 7-495-575-54-31
Fax No.: 7-495-573-87-10
E-mail Address: sheikhet @ laspace.ru

Alternate Technical Contact Information:
Name: Mikhail Artyukhov
Address: 141400, Himki City, Moscow Region, Russia, Leningradskaya str., 24 , Lavochkin Association
Phone No.: 7-495- 573-84-65
Fax No.: 7-495-573-87-10
E-mail Address: artyukh @ laspace.ru

Primary Science Contact Information:
Name: Roman Bebenin
Address: 117997, Moscow, GSP-7, Russia, Profsoyuznaya str., 84/32  AstroSpace Center
Phone No.: 7-495-333-2423
Fax No.: 7-495-333-2378
E-mail Address: rbeben @ asc.rssi.ru

Alternate Science Contact Information:
Name: Yuri Ponomarev
Address: 117997, Moscow, GSP-7, Russia, Profsoyuznaya str., 84/32  AstroSpace Center
Phone No.: 7-495-333-2423
Fax No.: 7-495-333-2378
E-mail Address: yupon @ asc.rssi.ru

Mission Specifics:

Scientific or Engineering Objectives of Mission: see Appendix: RADIOASTRON Booklet (The Ground – Space Interferometer: “radio telescope much larger than the Earth”)
Satellite Laser Ranging (SLR) Role of Mission: SLR Role is very important for this Mission, because Mission  is devoted to treat following astrometric problems:

  • Construction of a high precision celestial coordinate frame.
  • Development of a high precision model of the Earth gravitation field, and
  • Testing General Relativity by means of the precision redshift measurements.

Anticipated Launch Date: December of 2009
Expected Mission Duration: 5 years
Orbital Accuracy Required: As high as possible

Anticipated Orbital Parameters:

Altitude: 500 km – 350000 km
Inclination: 51.4 degrees
Eccentricity: 0.96
Orbital Period: 8.5-9.0 days
Frequency of Orbital Maneuvers: One Orbital Maneuver for one or two days
Mission Timeline: To be defined

Tracking Requirements:

Tracking Schedule: 30-60 minutes per 24 hours at request
Spatial Coverage:
Temporal Coverage:

Operations Requirements:

Prediction Center: Ballistic center of Keldysh Institute of Applied Mathematics
Prediction Technical Contact Information:
Name: Viktor Stepanyants
Address: 125047, Moscow, Russia, Miusskaya Sq. 4, Keldysh Institute of Applied Mathematics
Phone No.: 7-495-333-80-67
Fax No.: 7-495-972-07-37
E-mail Address: stepan @ kiam1.rssi.ru
Priority of SLR for POD: SLR is additional to Other measurings (for astrometric goals)
Other Sources of POD (GPS, Doppler, etc.): D,D(dot) will be processed by Control Stations (Bear Lakes & Ussuriysk) and Doppler will be processed by Tracking Stations constantly
Normal Point Time Span (sec): 1 minute
Tracking Network Required (Full/NASA/EUROLAS/WPLTN/Mission Specific):Stations with ability to perform Lunar Laser Ranging since H(apogee) ~350000 km

SECTION II: Tracking Restrictions:

Can detector(s) or other equipment on the spacecraft be damaged or confused by excessive irradiation, particularly in any one of these wavelengths (532nm, 1064nm, 846nm, or 423nm)? No
Are there times when the LRAs will not be accessible from the ground? Yes, segmentation files to be developed
(If so, go/nogo or segmentation files might be used to avoid ranging an LRA that is not accessible.)
Is there a need for an altitude tracking restriction? No
If yes, what altitude (degrees)?
Is there a need for a go/no-go tracking restriction? No
For what reason(s)?
Is there a need for a pass segmentation restriction? Yes
For what reason(s)? Because retroreflector array will be visible from Earth only for 30 – 60 minutes
Is there a need for a laser power restriction? No
Under what circumstances?
What power level (mW/cm2)?
Is manual control of transmit power acceptable? Yes

Other comments on tracking restrictions:

SECTION III: Retroreflector Information:

A prerequisite for accurate reduction of laser range observations is a complete set of pre-launch parameters that define the characteristics and location of the LRA on the satellite. The set of parameters should include a general description of the array, including references to any ground-tests that may have been carried out, array manufacturer and whether the array type has been used in previous satellite missions. So the following information is requested:

Retroreflector Primary Contact Information:
Name: Vladimir Vasiliev
Address: 53 Aviamotornaya st., Moscow, 111250, Russia, IPIE
Phone No.: +7(495)7071358
Fax No.: +7(495)2349859
E-mail Address: lavase r@ kmail.ru

Array type (spherical, hexagonal, planar, etc.), to include a diagram or photograph: Planar array, see pictures 1-4 of Appendix
Array manufacturer: Single retroreflector assembly (LRR), 100 units - Science Research Institute for Precision Instrument Engineering (IPIE). The retroreflector array consisting of 100 LRR units is made by Lavochkin Research.
Link (URL or reference) to any ground-tests that were carried out on the array:
The LRA design and/or type of cubes was previously used on the following missions: Cubes of similar design but with different coating (Al)  used  on GIOVE and GLONASS spacecraft.

The 3-D location (possibly time-dependent) of the satellite’s mass center relative to a satellite-based origin: See Appendix, Table 1
The 3-D location of the phase center of the LRA relative to a satellite-based origin: See Appendix, Pictures 2-4 and Table 2

However, in order to achieve the above if it is not directly specified (the ideal case) by the satellite manufacturer, and as an independent check, the following information must be supplied prior to launch:

The position and orientation of the LRA reference point (LRA mass-center or marker on LRA assembly) relative to a satellite-based origin: See Appendix, Picture 2
The position (XYZ) of either the vertex or the center of the front face of each corner cube within the LRA assembly, with respect to the LRA reference point and including information of amount of recession of front faces of cubes: N/A
The orientation of each cube within the LRA assembly (three angles for each cube): N/A
The shape and size of each corner cube, especially the height: Each Laser Retroreflector (LRR) unit comprises a cube corner prism retroreflector (CCR) installed in a housing equipped with a 50-mm long cylindric sun shade. The LRR equivalent optical aperture diameter at normal incidence is 28.2 mm; the distance from the prism face center to the prism vertex is 19.1 mm.  The height of one LRR unit is (46.5±1.5)g.
The shape and size of each corner cube, especially the height: Clear aperture diameter is 28.2 mm. The cube corner angles are exactly 90 degrees (not spoiled). This is because at distances more than 100,000 km the velocity aberration is small, and the not-spoiled dihedral angles provide maximum return signal strength. The final checking of the cube corners is made by measurements of the far-field diffraction pattern. The angular width of the pattern central lobe (full width at half maximum) is (4+0.2) arc seconds.
The material from which the cubes are manufactured (e.g. quartz): fused silica (quartz)
The refractive index of the cube material, as a function of wavelength λ (micron): n(0.423mc) =1.467856;  n(0.532mc) =1.460694;  n(0.846mc) =1.452340; n(1.064mc) =1.449666;
Dihedral angle offset(s) and manufacturing tolerance: 90 degrees +/- 0.5"
Radius of curvature of front surfaces of cubes, if applicable: N/A
Flatness of cubes’ surfaces (as a fraction of wavelength): lambda/20
Whether or not the cubes are coated and with what material: Cubes are Ag coated. There is no anti-reflection coating on the input face of the cube corner prism. The back faces are silver-coated.

Other Comments: The spacecraft can be seen by optical observatories almost every night. By the time the scientific program begins we will construct orientation required for one hour laser ranging interval every day. There are no direct restrictions for laser ranging on the special part of the orbit. But there are some restrictions on orientation of the spacecraft with respect to the Sun. Therefore for the next few months proper orientation of the spacecraft can be attained only on the out-bound leg of the orbit.
Orientation of the spacecraft does not change (in the inertial coordinate system) during the whole interval of laser ranging. The orientation is chosen according to the rule, that angle between line of sight and reflectors array normal should be less than 3 degrees for most of the stations that can see the spacecraft at high enough elevation angles (greater than 30 degrees).

SECTION IV: Mission Concurrence

As an authorized representative of the RadioAstron mission, I hereby request and authorize the ILRS to track the satellite described in this document.

Name (print): Nikolay Kardashev
Date October 2009
Position: Director of Astro Space Center of Lebedev Physical Institute in Moscow, Russia

Related Documentation: