During office hours, the average Dutchman looks at an uninteresting industrial area. How is it different for astronauts? The space photo of the week is the view taken by astronaut Jeffrey Hoffman during the first Hubble service mission in 1993.

The Hubble Telescope is a space telescope that has hovered above the Earth’s surface for over thirty years. Over the past few decades, the telescope has been visited and/or maintained by astronauts a total of six times. The first time was in 1990 (STS-31) when Hubble was launched into orbit from the Space Shuttle. The last time was in 2009.

Hubble needs glasses
Shortly after its launch in 1990, scientists discovered a problem with Hubble’s mirror. The telescope could not be focused and therefore all the photos were worse than expected. An analysis revealed that the mirror had been polished to the wrong shape. The gap should not be more than ten nanometers, but in the end the outer edge turned out to be 2200 nanometers too flat. The cause of the error: an incorrectly adjusted null corrector. A null corrector is an optical instrument used to test large aspherical mirrors. A lens from this null corrector was found to be installed 1.3 millimeters from the correct position and as a result the mirror was not ground correctly. A costly mistake.

Error corrected
On the first service mission (ST-61) in 1993, astronauts installed two new instruments: the Wide Field & Planetary Camera 2 (WFPC2) and the Corrective Optics Space Telescope Axial Replacement (COSTAR). These two devices fixed the primary mirror problem, allowing astronomers and many other amateur astronomers to finally enjoy razor-sharp images of space.

For example, a year later the Hubble telescope took the famous and now iconic photo of the so-called pillars of creation, or the gas pillars in the Eagle Nebula. In the decades that followed, thousands of other beautiful pictures followed.

Can James Webb be repaired in space?
While the Hubble Space Telescope was designed to be repaired in space, the James Webb Telescope is not. This space telescope was launched late last year and will begin scientific observations this summer. While the Hubble Space Telescope hovers about 550 kilometers above the Earth’s surface, the distance to the James Webb Telescope is 1.5 million kilometers. It is impossible for astronauts to visit this telescope and correct an error. After reading this, you will probably understand why James Webb’s mirrors have been retested and verified many times and why the launch has been delayed several times in recent years.

Incidentally, the Hubble Space Telescope is no longer repaired. The service mission in 2009 was also the last maintenance. More and more instruments are expected to fail in the coming years and the telescope will burn up in the atmosphere between 2028 and 2040. This ends an era.

Over the past few decades, space telescopes and satellites have captured beautiful images of nebulae, galaxies, stellar nurseries, and planets. Every weekend we delete one or more impressive space photos from the archives. Enjoy all the photos? Check them out on this page.