{"paper":{"title":"Propulsion Trades for a 2035-2040 Solar Gravitational Lens Mission","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Solar sailing to 650 AU for exoplanet imaging requires areal densities down to 2.3 g per square meter after a 0.05 AU perihelion pass.","cross_cats":["astro-ph.IM","gr-qc"],"primary_cat":"astro-ph.EP","authors_text":"Slava G. Turyshev","submitted_at":"2026-02-04T04:30:42Z","abstract_excerpt":"The Solar Gravitational Lens (SGL) enables resolved imaging and spectroscopy of nearby terrestrial exoplanets, but useful science begins only after a spacecraft reaches roughly 650-900 astronomical units (AU). A 20 yr lower-bound trip to 650 AU requires an average radial speed of 32.5 AU per year, or 154 km/s, before launch, targeting, steering, and operations margins. We compare close-perihelion solar sailing, fission-electric nuclear electric propulsion (NEP), and high-thrust Oberth injection followed by NEP cruise using common lower-bound outbound-leg architecture envelopes, not closed end-"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"For solar sailing, r_p=0.05 AU requires σ_tot ≃ 4.9 g m^{-2} for v_∞ ≃ 105 km/s and σ_tot ≃ 2.3 g m^{-2} for v_∞ ≃ 155 km/s, placing sub-20 yr sail-only access in an ultra-low-areal-density, deep-perihelion survivability regime. NEP with m0=20 t reaches 650 AU in ~27-33 yr for α_tot=10-20 kg kW_e^{-1}.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The models assume constant power for NEP and ideal sail performance without accounting for detailed trajectory optimization, real-world degradation factors, or inner-solar-system injection overhead.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"To reach the solar gravitational lens at 650 AU in under 20 years requires solar sails with areal densities of 2-5 g/m² or nuclear electric propulsion with specific masses of 3-15 kg/kW_e depending on architecture.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Solar sailing to 650 AU for exoplanet imaging requires areal densities down to 2.3 g per square meter after a 0.05 AU perihelion pass.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"ad0b32a7531617606d2c1a74e8245e95c84b30066103a39fd6e656df4adb0f34"},"source":{"id":"2602.04198","kind":"arxiv","version":3},"verdict":{"id":"aceca362-3307-4922-bdc2-bee4259d4421","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T07:44:21.839689Z","strongest_claim":"For solar sailing, r_p=0.05 AU requires σ_tot ≃ 4.9 g m^{-2} for v_∞ ≃ 105 km/s and σ_tot ≃ 2.3 g m^{-2} for v_∞ ≃ 155 km/s, placing sub-20 yr sail-only access in an ultra-low-areal-density, deep-perihelion survivability regime. NEP with m0=20 t reaches 650 AU in ~27-33 yr for α_tot=10-20 kg kW_e^{-1}.","one_line_summary":"To reach the solar gravitational lens at 650 AU in under 20 years requires solar sails with areal densities of 2-5 g/m² or nuclear electric propulsion with specific masses of 3-15 kg/kW_e depending on architecture.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The models assume constant power for NEP and ideal sail performance without accounting for detailed trajectory optimization, real-world degradation factors, or inner-solar-system injection overhead.","pith_extraction_headline":"Solar sailing to 650 AU for exoplanet imaging requires areal densities down to 2.3 g per square meter after a 0.05 AU perihelion pass."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2602.04198/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"2ec873028b3aea785b08b7079788a969f888c2fe9116541232c0024bcc507d87"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}