v0.9.0

SDP4 Deep-Space Propagator

astroz now handles all cataloged satellites — not just near-earth. GPS, GEO, Molniya, and other deep-space orbits (period > 225 min) are fully supported with SIMD-vectorized SDP4 propagation.

Everything auto-dispatches. Pass any TLE to Satrec.twoline2rv() or Constellation and it just works — SGP4 for near-earth, SDP4 for deep-space, no code changes needed.

What's new:

• Sdp4.zig / Sdp4Batch.zig — scalar and SIMD SDP4 with lunar/solar perturbations and resonance handling
• Satellite.zig — unified type that picks SGP4 or SDP4 automatically
• Constellation.zig — replaces Sgp4Constellation.zig, propagates mixed constellations with threading
• Satrec.is_deep_space property in Python
• Satrec.sgp4_array_into() — zero-copy SIMD batch for single satellites (SGP4 and SDP4)
• New benchmark scripts for JAX CPU/GPU comparisons

Breaking Changes (Zig only)

Python API has no breaking changes.

• Sgp4Constellation replaced by Constellation
• Sgp4Batch and simdMath now accessed via Constellation.Sgp4Batch / Constellation.simdMath
• DragCoefficients no longer stores perige — passed as a parameter instead
• Several Sgp4 internal types made pub for SDP4 reuse

Fixes

• Fixed non-compiling benchmarks (#80)
• CelestialBody constants refactored to use default field values