astroz 0.4.0

Python bindings for astroz - high-performance astrodynamics library

astroz Python bindings

Python bindings for astroz, a high-performance astrodynamics library written in Zig.

Performance

Using the batch numpy API, astroz significantly outperforms other Python SGP4 libraries:

Scenario	astroz	python-sgp4	skyfield	vs sgp4
1 day (minute res)	0.37 ms	0.54 ms	8 ms	1.5x faster
1 week (minute res)	2.6 ms	3.7 ms	50 ms	1.4x faster
2 weeks (minute res)	4.8 ms	7.4 ms	92 ms	1.5x faster
2 weeks (second res)	280 ms	460 ms	-	1.6x faster
1 month (minute res)	9.8 ms	17 ms	187 ms	1.7x faster

The raw Zig implementation achieves ~5 million propagations/second, outperforming the Rust sgp4 crate by 1.3-2.2x.

Installation

# Build the shared library first
cd /path/to/astroz
zig build c-api

# Install Python package
cd python
pip install -e .

Usage

import astroz
from astroz import Tle, Sgp4, orbital, coords

# Parse TLE and propagate with SGP4
tle = Tle("""1 25544U 98067A   24001.50000000  .00016717  00000-0  10270-3 0  9025
2 25544  51.6400 208.9163 0006703  40.6542 114.5435 15.49910020999999""")

sgp4 = Sgp4(tle)
pos, vel = sgp4.propagate(30.0)  # 30 minutes after epoch
print(f"Position: {pos} km")
print(f"Velocity: {vel} km/s")

# Convert to ground coordinates
gmst = coords.julian_to_gmst(2460310.5)
lat, lon, alt = coords.eci_to_geodetic(pos, gmst)
print(f"Lat: {lat:.2f}, Lon: {lon:.2f}, Alt: {alt:.1f} km")

# Orbital mechanics
transfer = orbital.hohmann(398600.5, 6778, 42164)  # LEO to GEO
print(f"Delta-V: {transfer['total_delta_v']:.2f} km/s")

API

TLE Parsing

• Tle(tle_string) - Parse two-line element set
• Properties: satellite_number, epoch, inclination, eccentricity, mean_motion

SGP4 Propagation

• Sgp4(tle, gravity_model=WGS84) - Initialize propagator
• propagate(tsince) - Single propagation (returns tuple)
• propagate_batch(times) - Batch propagation (returns list)
• propagate_batch_np(times) - Batch with numpy (fastest, returns arrays)

Coordinates

• coords.eci_to_ecef(eci, gmst) - ECI to ECEF
• coords.ecef_to_geodetic(ecef) - ECEF to lat/lon/alt
• coords.eci_to_geodetic(eci, gmst) - ECI to lat/lon/alt
• coords.julian_to_gmst(jd) - Julian date to GMST

Orbital Mechanics

• orbital.hohmann(mu, r1, r2) - Hohmann transfer calculation
• orbital.velocity(mu, radius, sma=0) - Orbital velocity
• orbital.period(mu, sma) - Orbital period
• orbital.escape_velocity(mu, radius) - Escape velocity