FA-69458 / Orbital propagation / Member archive

Two-line element set line 1: Minus signs are ignored by the checksum · case 03

Element sets with negative fields fail validation.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

Input one TLE line-1 string (exactly 69 characters, starting "1", else None). Epoch year from columns 19-20 (57-99 -> 1900s, 00-56 -> 2000s), epoch day 21-32, ndot/2 34-43, BSTAR 54-61 in assumed-decimal exponent form (" 34123-4" = 0.34123e-4, sign first), checksum column 69 (digits plus 1 per "-", mod 10). Return [year, day, ndot2, bstar rounded 14, 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 1 "1 11111U 75001A 57100.00000000 .00000000 00000-0 00000+0 0 14"	`[1957, 100.0, 0.0, 0.0, false]`	`[1957, 100.0, 0.0, 0.0, true]`	Failed

MEMBER ARCHIVE

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