Does a PS Vita Memory Card Fit in a PSP Go?

No. Physically and electrically incompatible.

Console	Memory Format	Dimensions
PSP Go	Memory Stick Micro (M2)	15 × 12.5 × 1.2 mm
PS Vita	PS Vita Memory Card (Proprietary)	28 × 21 × 2.8 mm

PSP Go Storage

Internal: 16 GB flash (non-removable).
Expandable: **M2 slot only.** Max official 16 GB (SanDisk/Sony). M2 cards obsolete, expensive, rare.
Workaround: M2→microSD adapters exist but unreliable (contact issues).

No adapter bridges M2 ↔ Vita card. Use M2 for PSP Go; Vita card for Vita.

PSP Games