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Picante

Picante is a Java implementation of the core functionality of NAIF SPICE.

Key features:

  • Pure Java; no native libraries needed
  • replicates NAIF SPICE ephemeris calculations and frame transforms to 1e-12 precision
  • Thread safe

Although Picante reproduces many SPICE capabilities, it is implemented very differently. Kernels are loaded into a " SpiceEnvironment". The user can instantiate multiple SpiceEnvironments to compare calculations with different sets of kernels, or to run a multithreaded application.

Picante was developed by the Analysis and Applications group of the Space Exploration Sector of the Johns Hopkins University Applied Physics Laboratory. It is released under the MIT License.

Maven Coordinates

Find the latest version at Maven Central.

<dependency>
    <groupId>edu.jhuapl.ses</groupId>
    <artifactId>picante</artifactId>
    <version>1.0.0</version>
</dependency>

Demo Code

The unit tests show how to replicate many common NAIF functions using Picante. The demo package contains a longer example, modeled on an example in the SPICE tutorials.

Many of the binary CK and SPK files needed to run the examples are not included in this repository. Run the getCK and getSPK scripts to download them from NAIF.

Incompatibilities with NAIF/SPICE:

  • CK types other than 2 or 3 are not supported.
  • Unsupported SPK types:
    • 10
    • 14
    • 15
    • 18 and higher
  • DSK files are not supported.
  • Product and Switch frames (new in N0067) are not supported.
  • Time format incompatibilities. Picante's TimeConversion class can parse all the example time format strings listed in the notes for STR2ET.
    • All times are assumed to be UTC. Neither time system modifiers (e.g. TT, TDT, TDB, etc) nor U.S. Time zones are supported.
      • TimeConversion fails on "2000 Jan 01 00:00:00 PST" but STR2ET will accept it.
      • TimeConversion fails on "2000 Jan 01 00:00:00 TDB" but STR2ET will accept it.
    • STR2ET will fail on the following examples, but TimeConversion will parse them:
      • 1997 Jan 32 12:29:29 translates to 1997-02-01T12:29:29.000
      • 1997 Feb 29, 12:29:20.0 translates to 1997-03-01T12:29:20.000
      • 1992 Mar 12 12:62:20 translates to 1992-03-12T13:02:20.000
      • 1993 Mar 18 15:29:60.5 translates to 1993-03-18T15:30:00.500
  • Built-in enumerations containing commonly used solar system bodies (CelestialBodies) and frames (CelestialFrames) have entries that deviate from the standard NAIF string names:
    • DE-### frames have the minus sign removed: DE###
    • The asteroid 52_EUROPA is assigned the entry: A52_EUROPA
    • The corresponding IAU body-fixed frame is: IAU_A52_EUROPA to preserve the IAU_ prefix property commonly expected.