Can You Download Super Mario Galaxy on Nintendo DS? No.

Super Mario Galaxy was released only on Wii (2007). It does not exist on Nintendo DS, 3DS, or any other platform.

Why It's Impossible on DS

• Hardware Gap: Wii (Broadway CPU @ 729 MHz, Hollywood GPU) vs. DS (ARM9/ARM7 @ 67/33 MHz, 2D engine). Galaxy's gravity physics, spherical worlds, and streaming require Wii power.
• Storage: Wii disc (4.7 GB) vs. DS cart (max 512 MB / 256 MB typical).
• Controls: Wii Remote pointer + Nunchuk essential for spin, star pointer, pull stars. DS touchscreen cannot replicate.

Mario on DS / 3DS

• New Super Mario Bros. (DS) — 2D platformer.
• Super Mario 64 DS — 3D remake of N64 classic.
• Mario Kart DS / 7
• Super Mario 3D Land (3DS) — Best handheld 3D Mario.
• Super Mario Galaxy 2 (Wii) — Sequel, also Wii-only.

Legal Ways to Play Galaxy

• Wii / Wii U (Backward Compatible): Original disc or Wii U eShop (closed — must have purchased).
• Nintendo Switch: Not available. Only in Super Mario 3D All-Stars (limited-time 2020–2021, delisted). Physical cart resale $60–100.
• Dolphin Emulator (PC / Android / Steam Deck): Runs Galaxy at 4K, 60 FPS, widescreen, HD textures. Legal if you dump your own Wii disc + keys.

Do not download "Mario Galaxy DS" — it's a scam/malware. Play 3D Land on 3DS or Galaxy on Dolphin.