Missing Link: Hubble Deep Field – A Photo and Its Story
Due to the costs and duration of the Hubble project, NASA was under pressure. At the end of 1995, it released a photo that silenced the critics.
The Pillars of Creation in the Eagle Nebula, one of Hubble's most famous photos
(Image: NASA)
The image was a sensation: for almost six days, the Hubble Space Telescope peered out from the Milky Way into a region of the sky outside our galaxy. From Earth, this area of the sky was considered empty.
The US space agency NASA had to deliver. The then-new space telescope threatened to become a multi-million dollar flop: construction was delayed, as was the launch after the explosion of the Space Shuttle Challenger in 1986. When it finally reached orbit in 1990, the great disappointment came: the optics had a serious flaw, and the images the telescope delivered were unusable.
To still be able to use the Hubble telescope, NASA commissioned a corrective lens, which a Space Shuttle brought to the telescope in late 1993. The telescope had already been drifting in orbit for more than three years at that point. In several spacewalks, Thomas Akers, Jeffrey Hoffman, Story Musgrave, and Kathryn C. Thornton gave Hubble new glasses.
Finally, the telescope worked – and now it had to deliver. And it did: the image of the supposedly empty patch of sky revealed millions of stars in thousands of galaxies, some of which date back to the early universe. The "Hubble Deep Field" is now one of the most iconic photos in space exploration, which has changed our view of the universe and for which several hundred scientific articles have been published.
(Image:Â NASA)
However, its origin story is just as interesting as the photo itself and the scientific insights gained from it. Less science was involved here than a lack of quality management at a US space company and US fiscal policy personified by a future Nobel Peace Prize laureate. And this story is at least as exciting as the scientific discoveries that followed from the photo.
Videos by heise
Idea from the 1970s
Looking back: It's 1975. After the idea of a space-based telescope had been discussed for almost three decades, and satellites with smaller telescopes were already operating in orbit, NASA submitted a budget request of 400 million US dollars to the US budget committee. This would be over 2 billion US dollars today. With this, the US space agency wanted to finance the construction of a "Large Space Telescope" with a mirror diameter of 3 meters. However, the project was rejected as "too expensive."
NASA revised the plans and reduced the diameter of the primary mirror (and thus the size of the telescope) to 2.4 meters. This halved the required budget. The money was approved in 1977, allowing NASA to commission the individual components in the following months.
In 1978, the contract for the telescope's primary mirror was awarded to the US company PerkinElmer. A new, laser-guided grinding process was used in its construction. PerkinElmer also used a measuring device adapted for the new process, a so-called "null corrector." Due to time and cost pressures, the new corrector was not tested and validated before use. Thus, no one noticed that a lens in the measuring system was offset by 1.3 mm due to faulty design. Because of a series of quality assurance failures at PerkinElmer, the error initially went unnoticed. In addition to the lack of validation, a whole series of other oversights were discovered later.
