Hubble
Hubble has been observing from low Earth orbit since 1990, above the atmosphere that blurs every telescope on the ground. It is still working, still producing science, and it is passing overhead right now.
What makes Hubble different
Above the air that blurs everything
Earth’s atmosphere smears starlight before it reaches any ground telescope. Hubble sits above all of it, which is why its images were sharp in a way nothing could match for decades — not because the mirror is large, but because nothing is in the way.
A famous mistake, fixed in orbit
Its 2.4 m mirror was ground to slightly the wrong shape and the first images came back blurred. A 1993 servicing mission fitted corrective optics — effectively spectacles — and it has worked as intended ever since.
Its orbit was chosen by the Space Shuttle
The 28.5° inclination is the latitude of the Kennedy Space Center. Hubble flies where it does because the Shuttle had to be able to reach it, and five servicing missions did exactly that between 1993 and 2009.
It is slowly coming down
With no servicing since 2009, atmospheric drag has been lowering the orbit ever since — the altitude above is meaningfully lower than it was at launch. Reboosting it is an open question rather than a plan.
Hubble was carried up by Discovery on 24 April 1990 and has since made well over a million observations. Its reputation rests less on size — 2.4 m is modest next to modern ground telescopes — than on position: above the atmosphere it receives ultraviolet light that never reaches the ground, and resolves detail no seeing-limited telescope can. The Hubble Deep Field, a long stare at an apparently empty patch of sky that came back full of galaxies, is probably the most consequential single image in modern astronomy. The altitude at the top of this page is propagated from a current element set, and it is lower than it was in 1990: without a servicing mission to reboost it, drag has been quietly winning.
Frequently asked questions
Where is Hubble right now?
The figure at the top of this page is its live altitude, with its ground position underneath, computed from current orbital data with the SGP4 model. Open it on the globe to watch it move.
Is Hubble still working?
Yes. It has lost instruments and gyroscopes over the years and now operates in a reduced mode, but it is still returning science more than three decades after launch.
Can I see Hubble from the ground?
Sometimes. It is fainter than the ISS but can reach naked-eye visibility on a good pass — though its 28.5° inclination means it never rises high in the sky from northern Europe or Canada.
Is Hubble being replaced by James Webb?
No. Webb observes in the infrared from 1.5 million km away at L2; Hubble covers ultraviolet and visible light from low Earth orbit. They see different light and neither does the other’s job.