Curator Michael Shara On 25 Years of Hubble

by AMNH on


Hubble Westerlund
Hubble scientists released this image of the star cluster Westerlund 2 to celebrate the telescope’s anniversary.

Friday, April 24 is the 25th anniversary of the Hubble Space Telescope. In its quarter century of operation, Hubble has broadened our understanding of the cosmos like no instrument before it. To mark the occasion, we spoke with Department of Astrophysics Curator Michael Shara, who worked with the Hubble mission during his time at the Space Telescope Science Institute. Dr. Shara and his collaborators have logged over 1,000 hours using the telescope for their work on star clusters, novae, and supernovae.


What did your work with the Hubble Space Telescope entail?

I joined the Space Telescope Science Institute (STSI) in 1982, eight years before the launch of Hubble. I was the project manager for the Guide Star Catalog that is used to target and calibrate the Hubble, and a few years after the telescope was launched, I was responsible for overseeing the peer review committees, which looked over proposals from researchers who wanted to use the telescope.

What was that experience like?

It was amazing to be able to see things coming in astronomy years before they were published. Reading hundreds of proposals and sitting in on deliberations about them was spectacular to watch.

How does it feel to look back on the launch of Hubble, 25 years out?

This anniversary is a joyous thing. Watching the deployment of Hubble in 1990 was an amazing, heart-stopping experience.

Pillars of Creation
The so-called Pillars of Creation are one of the most iconic images Hubble has captured. 

Hubble’s mission didn’t start out exactly as planned, though, did it?

The first three years were bumpy. When word came back that spherical aberration was preventing Hubble from focusing properly, I think everyone working on the project had the same terrible feeling in the pit of their stomachs. The mission to repair it in 1993 was even more tense than the initial launch, but it was wildly successful, and for the last 22 years, the story of Hubble has been one triumph after another.

What are some things that stand out in Hubble’s history?

It’s hard to pick one, because Hubble has just been a discovery machine. It’s the most productive telescope in history, with thousands of refereed papers published using Hubble data so far. One that stands out is the discovery of dark energy by groups using the Hubble. That was a totally unexpected discovery that essentially lobbed a hand grenade into the world of modern physics.

We also learned much  about our own solar system. For example, we saw a comet smash into Jupiter, which helped us understand how frequently these events occur, and what an important role they have played in the development of our solar system.

What makes Hubble such a “discovery machine?”

Part of it is the Hubble Archives. Every image, every spectrum, and every measurement that Hubble takes is stored by STSI. That data is proprietary to the researchers who first gathered it for one year. After that period, the information is free and open to other researchers, as well as the general public. That means there are many astronomers using data in ways the people who gathered it could not have foreseen, like using images that looked for a phenomenon known as microlensing in galaxies to find large populations of novae in those same galaxies.

Hubble Jupiter
Jupiter’s moon, Io, passes in front of the gas giant, casting a shadow on its surface.

How has this telescope changed since it was first deployed?

Every few years, Hubble has been upgraded, so it is a much more capable instrument today than when it was launched. The cameras are much more sensitive now, and the infrared and ultraviolet capabilities are vastly better than those available just a few years ago. 

After 25 years, how much life does Hubble have left?

Well, the instruments, computers, and gyroscopes on Hubble are doing really well. It’s conceivable that it will be useful until 2021 or 2022. After that, because we don’t have a shuttle program to boost it into a higher orbit, Hubble’s orbit will decay to the point where it finally falls to Earth. But the body of data that Hubble has collected is unmatched, and that information will be put to use for decades to come, and maybe even a century from now.