Engineered for modularity: each optical, structural, and electrical subsystem can be isolated, assembled, exploded, and inspected in real-time 3D.
Hubble utilizes two hyperbolic mirrors. Starlight enters the forward baffle, hits the 2.4m primary mirror, focuses forward onto the 30cm secondary mirror, and reflects back through a 60cm central hole directly into the rear science instruments without coma aberration.
To capture galaxies billions of light-years away without motion blur, four stainless steel reaction wheels spin at up to 3,000 RPM. Guided by 3 Fine Guidance Sensors, Hubble locks onto target stars with the stability of a human holding a laser on a coin 320 kilometers away!
Unlike any other space telescope, Hubble was designed for orbital maintenance. Over 5 Space Shuttle servicing missions, astronauts replaced gyroscopes, solar arrays, power units, and installed modern instruments like WFC3 and COS directly in space.