Planets.si
Explore the solar system with an AI astronomy guide
Planets, moons, and the missions exploring them - from Mercury to the outer solar system and beyond, explore astronomy with an expert guide built for the curious.
No card required · $9/mo Plus · $99/mo Premium
What you get
Everything Planets.si gives you
orbit
Every planet and moon
The solar system explored in accurate, accessible detail.
rocket
Real missions
Voyager, Cassini, JWST, and rovers - what they found and why it matters.
telescope
Confirmed vs. hypothesis
Established data kept clearly separate from active research.
bookmark
Saved study threads
Sign in free and keep every conversation for later study.
Pricing
Simple plans that grow with you
Most popular
Plus
$9/mo
- ✓200 questions per day
- ✓Full saved conversation history
- ✓Extended mission deep-dives
Premium
$99/mo
- ✓Unlimited questions
- ✓Deep-dive technical breakdowns
- ✓Everything in Plus