Science writing: keep asking why?

Hubble gyros fixed after struggle, the BBC told us on Friday, but didn't explain what a gyroscope is or why it needs to be fixed.

Every journalist knows the importance of the who-what-why-where-when formula but so often the answer to the why goes missing. In fairness, it is generally the toughest question to answer. But it is also the most significant because, without it, the reader doesn't get the point of the story.

Astronauts have completed the most critical repair to the Hubble Space Telescope after a long struggle, the story goes on.

Why is it the most critical repair? The writer doesn't make that clear either.

A gyroscope is like a spinning top. As long as it keeps spinning it will stay the same way up. Spacecraft use them so they know which way they are pointing. They are critical to the Hubble Telescope because a telescope is pretty hopeless if you don't know which way it is pointing.

This is what a NASA gyroscope looks like by the way

In practice, gyroscopes are a bit fancier than spinning tops. They are precision machined and work like an electric motor to keep them rotating. They also have tiny sensors to detect their movement and tell the telescope which way up it is.

Herein lies the problem. Keep a tiny, precision motor running for 19 years and it is likely to wear out or break down. Hence NASA's mission to replace them.

There that wasn't so hard, was it? Source of the information . . . wait for it . . . NASA.

Space repairs make an exciting enough story without detailed explanation. But don't you think the reader deserves to know more about the science after they have read a story like this?