1. NRAO-GB Support for VSOP-2
Glen Langston
National Radio Astronomy Observatory
Green Bank, WV USA
NRAO Goals
Support Space VLBI Science
Ground Tracking VLBI support
Develop Systems for integration into future Ground Science systems
Langston: VSOP-2 at Yebes 06

2. Langston: VSOP-2 at Yebes 06
NRAO GB 20m
Proven Operation at 2 to 9 GHz
Surface RMS .3mm
Should be good at 40 GHz.
Prime focus optics
VLBI antenna
Fast 2deg/second
Langston: VSOP-2 at Yebes 06

3. Langston: VSOP-2 at Yebes 06
20m Link Budget
Need to plan link for worst Case: rain, 300 K
37.5 GHz margin 8.3 dB
26.0 GHz margin 6.7 dB
(Pointing error < at 26 GHz)
Need model of phase stability noise contributions
Ionosphere
Troposphere
Clock noise
SNR of return Signal
Station position
Rx/IF un-modeled delay variations
Langston: VSOP-2 at Yebes 06

4. Weather/Opacity vs frequency
Opacity is similar (factor of 2) at 26 and 38 GHz
GB has daily weather model
Bad weather today….
Langston: VSOP-2 at Yebes 06

5. Weather/Opacity vs time
Langston: VSOP-2 at Yebes 06

6. Langston: VSOP-2 at Yebes 06
Antenna Signal Path
All Items JAXA/ISAS
Feed NRAO
Receiver NRAO/All
Satellite Sim. JAXA/Custom
Transmitter Commercial
Timing Tone Custom/Commercial
Phase Measurement Custom/Commercial
Demodulator Digital Custom/Commercial
Decoder Custom/Commercial/Software
Recorder Mk V/Commercial
Data Extraction NRAO/Custom
Monitor Custom
Schedule Custom
Langston: VSOP-2 at Yebes 06

7. NRAO Contributions/Interests
$$$ Antenna
$$ Software
$ Low Noise Front Ends
$ Uplink/Downlink phase control/detection
$ Software Back Ends (real-time spectra/calibration of VSOP-2 data)
Test correlation
Transient Searches
Continuum imaging
Galactic molecules
Langston: VSOP-2 at Yebes 06

8. Langston: VSOP-2 at Yebes 06
Costs
$$$ Antenna
$$ Design Engineer
$$ Software
$ Individual Modules (but these add up…)
Langston: VSOP-2 at Yebes 06

9. Langston: VSOP-2 at Yebes 06
Conclusions
The NRAO in GB Supports the Science Goals of the VSOP-2 Mission.
GB will support GBT Science Observations of successful proposals.
The NRAO in GB is willing to support VSOP-2 Ground Tracking.
NRAO’s top ground tracking priority
Develop technology and software for spacecraft tracking that has applications for GB science operations.
Langston: VSOP-2 at Yebes 06

10. Ionospheric Incoherent Scatter
First light detection of bistatic incoherent scatter from the F region ionosphere on a Millstone Hill to NRAO Green Bank forward path on 25 January 2006, at the common volume intersection point in geodetic coordinates: (40 deg lat, 283 deg lon, 300 km altitude). The upper data was collected using the reference Millstone Hill software radar platform in a monostatic configuration, while the lower data was collected on the MIDASMobile #001 platform at NRAO Green Bank. An uncoded 480 usec pulse was transmitted from Millstone Hill, resulting in a predicted and subsequently observed bistatic signal to noise ratio of 21 dB. Although the bistatic return appears to be approximately 80 km long in range, the actual ionospheric altitude resolution (set by common intersection volume size) is 10 km.
Langston: VSOP-2 at Yebes 06

11. Molecule/Transient Survey
Technology has advanced.
Digital Spectra Pulsars and Transients in 1 backend
Transients at 43GHz
High Stability
Molecule Survey
All Sky coverage
Langston: VSOP-2 at Yebes 06

12. Recent Test Data Obtained
Langston: VSOP-2 at Yebes 06

13. Langston: VSOP-2 at Yebes 06
Bi-Static Radar
Langston: VSOP-2 at Yebes 06

14. Langston: VSOP-2 at Yebes 06
GBT
Operation at 0.3 to 49 GHz
Dedicated participation High Sensitivity Array VLBI
Langston: VSOP-2 at Yebes 06