<p>15 years.</p>
<blockquote>
<p>Hubble was designed with an anticipated 15-year lifetime based on the expected integrity of the main mirror. It was believed that over HST’s 15-year life the space environment in low Earth orbit would cause sufficient degradation of the mirror that the telescope’s light-gathering capabilities would be severely damaged by cosmic rays and orbital debris.</p>
</blockquote>
<p>Source: <a href="https://www.nap.edu/read/11169/chapter/4#12" rel="noreferrer">Assessment of Options for Extending the Life of the Hubble Space Telescope: Final Report</a></p>
<p>It is notable that Hubble was, from the start, intended to be a serviceable telescope. There were plans made before its launch and before the fault in the main mirror was found, to have astronauts visit the telescope to replace, repair and upgrade the platform.  (This was a first. No prior satellite was designed to be serviced in space)</p>
<p>The main mirror would not be replaceable, and it was expected (or feared) that it would degrade over a time scale of about 15 years.  It was clear, however, in 2005 that this degradation hadn't occurred, and so further service missions were carried out to maintain and improve the HST's operation, and boost it to higher orbits (compensating for drag).</p>

CC BY-SA 4.0
2021-06-05T04:53:49.383Z
I've just asked (in Space SE): [How was the high rate of degradation of Hubble's main mirror initially predicted? Why did it turn out to be lower? Were cosmic rays really a concern?](https://space.stackexchange.com/q/53538/12102)
uhoh
CC BY-SA 4.0
2021-06-04T17:23:06.037Z
2021-06-05T04:50:11.247Z
2021-06-05T04:50:11.247Z
James K
<p>For space missions, there is typically a minimum time that is defined for the mission to fulfill all of its science objectives, then an extended mission with extra objectives. And after that, the mission can be extended as long as the hardware works and funding is approved.</p>
<p>The Hubble Space Telescope has been working for 30 years now, but how long was its initial mission supposed to last?</p>

CC BY-SA 4.0
2021-06-04T19:10:47.670Z
I was tempted to say "only for the remainder of FDR's term, but then he was re-elected."
stretch
<history><hubble-telescope>
How long was the HST initially supposed to work?
usernumber
# How long was the HST initially supposed to work?

(Asked by: username_0 on 2021-06-04)

For space missions, there is typically a minimum time that is defined for the mission to fulfill all of its science objectives, then an extended mission with extra objectives. And after that, the mission can be extended as long as the hardware works and funding is approved.

The Hubble Space Telescope has been working for 30 years now, but how long was its initial mission supposed to last?

**Tags:** history, hubble-telescope

> **Comments:**
> **username_1**: I was tempted to say "only for the remainder of FDR's term, but then he was re-elected."  

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## 1 answers

### Answer by username_2 on 2021-06-04. Score: 11 | Accepted answer

15 years.

> Hubble was designed with an anticipated 15-year lifetime based on the expected integrity of the main mirror. It was believed that over HST’s 15-year life the space environment in low Earth orbit would cause sufficient degradation of the mirror that the telescope’s light-gathering capabilities would be severely damaged by cosmic rays and orbital debris.

Source: [Assessment of Options for Extending the Life of the Hubble Space Telescope: Final Report](https://www.nap.edu/read/11169/chapter/4#12)

It is notable that Hubble was, from the start, intended to be a serviceable telescope. There were plans made before its launch and before the fault in the main mirror was found, to have astronauts visit the telescope to replace, repair and upgrade the platform. (This was a first. No prior satellite was designed to be serviced in space)

The main mirror would not be replaceable, and it was expected (or feared) that it would degrade over a time scale of about 15 years. It was clear, however, in 2005 that this degradation hadn't occurred, and so further service missions were carried out to maintain and improve the HST's operation, and boost it to higher orbits (compensating for drag).

> **Comments:**
> **username_3**: I've just asked (in Space SE): [How was the high rate of degradation of Hubble's main mirror initially predicted? Why did it turn out to be lower? Were cosmic rays really a concern?](https://space.stackexchange.com/q/53538/12102)  

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