Fractional CTO and engineering leadership. Architecture review, technical due diligence, and interim head-of-engineering work, mostly for teams with hard systems problems.
The repos here are public work product. Both are MIT licensed.
github.com/arboreng/cislunar-sim
Spacecraft trajectory simulation from LEO through cislunar space, in Python. A validated physics engine plus Q-law guidance, without GMAT's XML configuration or Orekit's Java dependency.
The force model covers J2/J3 and 8-mascon GRAIL lunar gravity, third-body solar perturbation, Hall-effect ion thrust, solar sail SRP, NRLMSISE-00 drag, eclipse shadowing, and quaternion attitude dynamics, integrated with adaptive RK4(5). Runtime dependencies are numpy, astropy, and nrlmsise00.
Validation against LightSail 2:
| Check | Result | Reproducible from clone |
|---|---|---|
| SMA error vs. SGP4-propagated states | < 0.05% | yes |
| Radial error | < 0.02% of orbital radius | yes |
| Sail force vs. McInnes (1999) | within 1% | yes |
| B* swing ratio (sailing / passive) | 0.231 observed, 0.228 predicted | needs CelesTrak GP archive |
| Eclipse entry timing | mean +3.7 s, std 19.5 s | needs SatNOGS beacon data |
pip install cislunar-simgithub.com/arboreng/pq-migration-lab
Post-quantum cryptography migration patterns, in Go. The algorithms are standardized and reference implementations exist; what's less documented is what breaks when a running system moves to them.
Four migration demos, each runnable end to end:
hybrid-tls— TLS 1.3 handshake overX25519MLKEM768with no fallback group offered on either sidecert-migration— one classical Ed25519 CA issuing both Ed25519 and ML-DSA-65 leaf certificatesca-rotation— rotating a CA from Ed25519 to ML-DSA-65 with a cross-signed transitional certinterop-tls— the same hybrid group between Go'scrypto/tlsand OpenSSL withoqs-provider, in both directions
Benchmarks for X25519 vs. ML-KEM-768 and Ed25519 vs. ML-DSA-65 are generated from go test output.
docker compose run pqlab demo hybrid-tls