Small-Body Radar Astrometry API

Version: 1.1 (2022 February)
change log

The small-body radar astrometry API provides a method of requesting specific records from the available data-set for asteroids and/or comets. Every successful query will return content representing one or more radar astrometry data record. See the SSD page on radar astrometry for details on this data-set.

HTTP Request

GET https://ssd-api.jpl.nasa.gov/sb_radar.api

Example Queries

• https://ssd-api.jpl.nasa.gov/sb_radar.api (return all available data)
• https://ssd-api.jpl.nasa.gov/sb_radar.api?kind=c (return data only for comets)
• https://ssd-api.jpl.nasa.gov/sb_radar.api?des=433 (return data only for 433 Eros)
• https://ssd-api.jpl.nasa.gov/sb_radar.api?kind=an&coords=1 (return data for numbered asteroids with station coordinates)

Query Parameters

Data Output

Please always check the JSON payload “signature” object for the API “version”. If the version does not match the version in this document (at the top), there is no guarantee that the format has not changed.

Example "signature" object with "version" value "1.0": "signature":{"version":"1.0","source":"NASA/JPL ... API"}

Data are returned in JSON format as a single object (hash-table). The number of records contained in the object is indicated in the “count” key. In cases where the user-specified constraints are too tight (no matching results), only the “count” and “signature” keys are returned, as in the following example.

{ "count":0, "signature":{"version":"1.0","source":"NASA/JPL Small-Body Radar Astrometry API"} }

Each record is provided as an element of the “data” object and each record is an array of fields. The names of each field contained in each record is provided in the “fields” object array. Records are sorted first by object (in order by group: unnumbered comets, numbered comets, unnumbered asteroids, and numbered asteroids) then by measurement in reverse chronological order.

The fields are defined as follows.

Sample Data Output

{
  "signature" : {"source" : "NASA/JPL Small-Body Radar Astrometry API", "version" : "1.0"},
  "count" : "3",
  "fields" : [ "des","epoch","value","sigma","units","freq","rcvr","xmit","bp" ],
  "data" : [
    [
      "1997 WQ23",
      "2013-11-22 01:53:00",
      "111982347.7",
      "1.000",
      "us",
      "2380",
      "-1",
      "-1",
      "C"
    ],
    [
      "1997 WQ23",
      "2013-11-19 00:38:00",
      "96148022.94",
      "4.000",
      "us",
      "2380",
      "-1",
      "-1",
      "C"
    ],
    [
      "1997 WQ23",
      "2013-11-19 00:25:00",
      "-124458.2215",
      "0.300",
      "Hz",
      "2380",
      "-1",
      "-1",
      "C"
    ]
  ]
}

Radar Stations

Radar stations codes are indicated by a negative integer (e.g., “-14” for “DSS 14”). Common radar station codes are listed in the table below.

If requested via the coords query parameter option, each radar station’s coordinates in the requested radar astrometry will be output under the JSON coords object. By default, these coordinates are output as geodetic (longitude, latitude, and altitude). If the c-coords query parameters is set, the coordinates are output in cylindrical form (longitude, d_xy, and d_z). The following tables detail these fields and their units.

Geodetic Coordinates

Cylindrical Coordinates

Sample Data Output

...

"coords" : {
  "-1" : {
    "alt_units" : "m",
    "altitude" : "450.56",
    "latitude" : "18.34420",
    "longitude" : "293.2473",
    "name" : "Arecibo"
  },
  "-13" : {
    "alt_units" : "m",
    "altitude" : "1067.86",
    "latitude" : "35.24720",
    "longitude" : "243.2055",
    "name" : "DSS 13"
  },
  "-14" : {
    "alt_units" : "m",
    "altitude" : "1006.94",
    "latitude" : "35.42590",
    "longitude" : "243.1105",
    "name" : "DSS 14"
  }
},

...

HTTP Response Codes

All errors are returned via appropriate HTTP response codes.

Change Log

Version 1.1 (2022 February)

• Corrected cylindrical coordinates units in the documentation and fixed the sign on their values.

Version 1.0 (2021 June)

• Initial release