The Hubble Space Telescope’s amazing replacement is almost ready

The final giant mirror has been installed at long last

For 25 years, the Hubble Space Telescope has been an extraordinary tool for astronomers and has mesmerised us all with breathtaking views of our universe. We’ve peered billions of years into the past; learnt more about our solar system; and measured the expansion of the universe, all thanks to the Hubble. Repairs and upgrades have extended its lifespan but it’s starting to show its age. In the time Hubble has been in space, we’ve developed better technology. In 2018, NASA will launch its replacement: the James Webb Space Telescope (JWST).

The JWST has seen a difficult journey already and it hasn’t even set off for space. When the telescope was proposed back in 1996, NASA sought a budget of $500 million. So far it has cost $8.6 billion, it’s taken far too long to build, and it isn’t even finished. Finally we have some good news as this week sees an important milestone reached: the installation of the 18th and final mirror.

Image © NASA/Chris Gunn

Before you ask how hard it can be to install mirrors, realise these are no bathroom mirrors being used on the JWST. Each of the 18 mirrors is made of beryllium, weighs 40 kg, and is 1.3 m across. Engineers have been working around the clock since Thanksgiving to install the mirrors. Now that they’re all in place, the final components can be added before the telescope is tested for durability. If all goes according to plan, it will be in space by 2018.

The skyrocketing costs and countless delays over the years have left some people angry that NASA is wasting time and money. I think it will be worth the wait as the JWST completely outclasses the Hubble telescope. The new telescope will take up residence 1.5 million km from the Earth, far from our light pollution. There it will unfold its mirrors, which combine to form a telescope with a 6.5 m diameter. For comparison, the Hubble’s telescope diameter is 2.4 m. The improvement is extreme and will help us learn more about the universe than ever before. We’ll see things that Hubble never had a hope of glimpsing such as the very first stars that formed after the big bang, and newly forming galaxies and solar systems.

The Hubble has served us well for a quarter of a century and changed how we view our universe. The JWST has been in development hell but soon we’ll have a killer replacement peering back in time to the very earliest stars. That’s probably $8.6 billion well spent.

If you can’t wait until 2018, check out the amazing launches happening this year.