Scenario kind pagesEdit on GitHubSource: docs/kinds/by-kind/ascent-losses.md

ascent-losses (scenario kind)

Scenario kind of the engine v0.38.0, family Mission analysis, links and space operations. Advisory: analysis output from a research and engineering tool, not type-approved navigation equipment and not a safety-of-life service. Every label here is the engine's or the verification matrix's; a kind is MODELLED unless the matrix says otherwise (how a label is earned: the README's Evidence section).

What it does#

Planar gravity-turn ascent of a multi-stage vehicle over a non-rotating spherical Earth through the US Standard Atmosphere 1976 (vertical rise, pitch kick, thrust along velocity), integrating the gravity, drag, steering and back-pressure losses and checking ideal dv minus losses against the burnout speed; max-Q, peak acceleration and burnout state. MODELLED.

One run of scenarios/ascent-losses.toml summarises as: ascent-losses: ideal dv 11290 m/s, losses 2359 m/s (gravity 2276, drag 15, steering 0, back-pressure 67); burnout 509 km at 8932 m/s, gamma 8.7 deg; max-Q 32.5 kPa (MODELLED)

Inputs#

From the schema (kshana kinds --json):

  • Required fields: none
  • Optional fields: stages, payload_kg, drag_coefficient, reference_area_m2, kick_altitude_m, kick_angle_deg, kick_duration_s, step_s

The example scenarios/ascent-losses.toml sets, among others:

Field Value Unit
drag_coefficient 0.3 1
kick_altitude_m 1000 m
kick_angle_deg 3 deg
kick_duration_s 10 s
kind ascent-losses text
payload_kg 10000 kg
reference_area_m2 10.5 m^2
stages[0].dry_mass_kg 25000 kg
stages[0].exit_area_m2 6 m^2
stages[0].isp_vac_s 311 s
stages[0].propellant_kg 400000 kg
stages[0].thrust_vac_n 7600000 N

Run it#

kshana scenarios/ascent-losses.toml

What it gives#

The scalar results of that run, with the units the engine states:

Result Value Unit
burn_time_s 508.755519 s
crashed false flag
end.altitude_m 5.0903e5 m
end.circular_speed_m_s 7607.618569 m/s
end.downrange_m 1.5142e6 m
end.flight_path_angle_deg 8.707144 deg
end.speed_m_s 8931.555867 m/s
ideal_dv_m_s 11290.251582 m/s
identity_residual_m_s 7.1304e-10 m/s
inputs.drag_coefficient 0.3 1

Result label (the engine's): MODELLED — planar gravity-turn ascent of a multi-stage vehicle over a non-rotating spherical Earth through US76, with gravity, drag, steering and back-pressure losses integrated and the ideal-dv-minus-losses identity checked; constant C_D, no rotation, no coast, no guidance beyond the pitch kick

The chart the engine writes for scenarios/ascent-losses.toml, kind ascent-losses

Evidence#

MODELLED: the verification matrix rows that name this kind.

  • MODELLED Planar gravity-turn ascent of a multi-stage vehicle over a non-rotating spherical Earth through the US Standard Atmosphere 1976 (density and pressure), with a pitch kick, thrust reduced by the nozzle back-pressure, stage burnouts at exact s

The rows the run itself exercised, with the oracle the matrix gives each (the public sources are named there):

  • MODELLED Deterministic, scenario-hashed, SBOM + cross-platform golden gates. Oracle (ExternalDataset): SBOM conformance to the official CycloneDX 1.5 JSON Schema (+ valid SPDX identifiers) — an external published standard, zero validation errors over the full dependency graph; the FoM-determinism / byte-reproducibility part remains a pinned self-consistency check, so the row stays MODELLED
  • MODELLED Planar gravity-turn ascent of a multi-stage vehicle over a non-rotating spherical Earth through the US Standard Atmosphere 1976 (density and pressure), with a p. Oracle (InternalConsistency): Internal consistency: the exact identity burnout speed = sum Isp g0 ln(m0/mf) minus the four integrated losses (residual below 1e-6 m/s), Tsiolkovsky's equation on a vertical vacuum burn with gravity the only loss, and the US76 sea-level and tropopause pressures. WHAT IS NOT: no published vehicle's losses have been compared; no Earth rotation, coast, throttling or guidance beyond the kick; constant C_D; not a traject

Limitations#

What the run's own report says is not modelled or not validated:

  • MODELLED — planar gravity-turn ascent of a multi-stage vehicle over a non-rotating spherical Earth through US76, with gravity, drag, steering and back-pressure losses integrated and the ideal-dv-minus-losses identity checked; constant C_D, no rotation, no coast, no guidance beyond the pitch kick (result label)
  • MODELLED. (kind catalogue (kshana kinds --json))
  • Gravity-turn ascent losses of an ILLUSTRATIVE two-stage kerosene/oxygen launcher (no real vehicle): vertical rise to 1 km, a 3 deg pitch kick for 10 s, then thrust along the velocity. The run integrates the gravity, drag, steering and back-pressure losses and checks that ideal dv minus the losses equals the burnout speed. MODELLED: planar, non-rotating Earth, constant C_D, no coast, no guidance beyond the kick. (scenario file comment, lines 1 to 5)
  • Reproducibility & software assurance is MODELLED, not validated: a sub-claim is externally checked, but the whole capability composes modelled pieces, so the capability stays Modelled. (verification matrix (docs/MODELLED-RATIONALE.md))
  • Launch ascent gravity, drag, steering and back-pressure losses is MODELLED, not validated: checked against its own closed-form / analytic identity — catches transcription and coefficient errors, but is not an external oracle. (verification matrix (docs/MODELLED-RATIONALE.md))

See also#