FA-69429 / Orbital propagation / Member archive

Two-line element set line 2: Checksum includes its own digit · case 04

Valid element sets are rejected as corrupt.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input one TLE line-2 string. It must be exactly 69 characters and start with "2", else None. Fields by 1-based columns: inclination 9-16, RAAN 18-25, eccentricity 27-33 with an implied leading decimal point, argument of perigee 35-42, mean anomaly 44-51, mean motion 53-63, revolution number 64-68, checksum 69 (sum of digits in columns 1-68, "-" counts 1, mod 10). Return [inc, raan, ecc, argp, M, n, rev, checksum_ok].

Why this case matters

Orbit determination and mission planning chain many small conversions; one wrong branch or unit silently moves a spacecraft by kilometres.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
two-line element set line 2 "2 28654 98.9000 120.7000 0014000 300.2500 59.9000 14.12501077999994"	`[98.9, 120.7, 0.0014, 300.25, 59.9, 14.12501077, 99999, false]`	`[98.9, 120.7, 0.0014, 300.25, 59.9, 14.12501077, 99999, true]`	Failed

MEMBER ARCHIVE

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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