Instrument/Mission/Data requirements for the Solar Radio Imaging Array 

This table has been created for the Solar Imaging Radio Array (SIRA) Science Workshop (May 13-14, 2003) and lists a subset of the known SIRA mission requirements.  Please email us at robert.macdowall@nasa.gov if you have questions. 
Instrument requirements
Angular resolution
~1 arcmin @ 15 MHz
 anti-Sunward; in the direction of the Sun, the resolution at 15 MHz can be as low as 0.5 deg
Dynamic range
>90 dB
  needed to permit removal of  intense sources and interference from data with weaker events
Frequency range
30 kHz - 15 MHz
  corresponding to distances from the Sun of 2 R_sun to 1 AU
Frequency spacing
10 kHz
  (available frequency list)
Number of imaging frequencies
~16 (log-spaced)
  provides reasonable mapping of radial evolution from Sun to 1 AU
Frequency bandwidth
<5 % (center freq.)
  
Frequency sampling scheme
type III burst adapted
  higher frequencies are sampled more frequently
Nyquist sampling 
2-bit
  (at 0.5 cycles of the wave)
Full power sampling
16 bit 
  for calibration and dynamic spectra data
Instantaneous sensitivity
100 kJy
  
Antennas crossed 10 m dipoles  
Radio receivers
2 per spacecraft
Microsatellite requirements
s/c stabilization
3-axis stabilized
  facilitates data processing
antenna "pointing" accuracy
 +/-2.5 deg
  facilitates data processing
Mission requirements
Number of microsats
12-16
  provides adequate number of baselines
Microsat relative locations
50 km shell
  provide uniform coverage of the u-v aperture plane (a “spherical” constellation)
Intersatellite ranging resolution
3 m
  
Orbit
considering ...
  lunar L4/L5 (60 R_e), solar L1 (210 R_e), and distant retrograde orbit (170-220 R_e)
Total data rate (16 s/c)
~600 kb/s
Daily data storage (16 s/c)
7 GB
Downlink interval
~4 hr/day
  bidaily data dumps desirable for space weather
Data availability (snapshots)
<24 hr
  required for space weather applications
Mission lifetime
 2 yr (minimum)
Proposal opportunity
NASA MIDEX
  AO anticipated April 2004
Data/Archival Requirements
Data products include: routine images of "radio" transients; routine high-frequency-resolution dynamic spectra displays for comparison with single antenna observations; CME/shock catalog: source regions, velocities, notes, coordinated with coronograph obs. (SDO, etc.); magnetic field line mapping matched to available in situ observations and modeled with solar source & CME disturbances; catalog of energetic electron sources compared with imaged/modeled magnetic field lines; forecast of arrival times of fast CMEs at Earth; CME & shock observations applied to standard forecasting models; images, analysis, & modeling of Earth's response to arrival of transients in the solar wind; full-sky maps of all <15 MHz sources: catalog & analyze galactic dist. of diffuse HII, sources of cosmic rays (CRs), new sites of coherent emission, very old SNRs & GRB remnants, galactic dist. of low energy CR electrons, inner scale of turbulence in ISM, "fossil" radio galaxies, extended halos of clusters of galaxies, distribution of low-energy CRs in nearby galaxies
Archival products include:  visibility (raw) data, total power data, cleaned "snapshot" data (solar/heliospheric & magnetospheric), high time resolution dynamic spectra images and digital data, full-sky maps