How Hubble almost failed 

The hubble space telescope is one of the most iconic and history changing space telescopes. Named after Edwin Hubble, it launched in 1990, 24th april and has revolutionised space history ever since. Even though there are contenders for its top position amongst space telescopes, such as the recently launched James Webb Space Telescope, it is a timeless star spotting, history making and scientifically revolutionary piece of machinery, it is loved by millions all around earth and simply the best for its time. Hubble has produced several iconic images of different stars (Shown below i.1) it has a crystal-clear view of the universe. Scientists have used Hubble to observe some of the most distant stars and galaxies yet seen, as well as imaging planets within our solar system. (see below i.2)

Even though the Hubble has been around for over 30 years now, its capabilities are still emerging and growing immensely, this is due to science continuously revolutionising, new cutting-edge technology being implemented and new scientific instruments that have been added to the Hubble over a course of 5 astronaut servicing missions. These servicing missions/visits have drastically increased its lifespan, and stopped all the parts from ageing and deteriorating any more. The last and final servicing mission was in 2009 and the telescope even as off today is doing well and scientists say that the hubble will continue working until its components continue to work and execute its functions optimally.Hubble is not expected to re-enter earth's atmosphere until mid to late 2030s, so we can expect much more to come from it with the years coming.

Hubble has made over 1.5 million observations over the course of its lifetime. Over 19,000 science papers have been published with its findings throughout the science community. Hubble has tracked several phenomenal interstellar objects as they charged through the solar system, it’s seen a comet collide with Jupiter with phenomenal view and clarity (see below i.3) and even spotted locations more than 13.4 billion lightyears away from earth. The Hubble space telescope scopes through a particular range of light waves, it can see all the way from ultraviolet and into near-infrared providing a fantastic range of light that can be seen helping produce such stunning images of stars (see below i.4), galaxies and the like. These have changed our understanding of astronomy massively. 

Shortly after the Hubble’s launch, its operators discovered a detrimental flaw within the telescope’s primary mirror, it had a defect that affected the clarity of its early images produced. A slight fracture on the surface, about the size of 1/50th of a human hair, now that's crazy! The team at NASA ran an investigation in order to diagnose and solve the problem. After the investigation, the team stated that the imaging issue was caused by a mis calibration during the primary mirror’s manufacture. In order to solve this issue, replacing the mirror would not work quite obviously, they would have to bring the telescope back down to earth or execute a very hard operation, in space. The option to fix this problem that the operators at NASA chose to use was to build replacement instruments that would fix the defect, in a similar way that human’s eyesight can be fixed by wearing the correct lens of glasses. These instruments were built and installed in the Hubble Space Telescope in 1993 during a spacewalk by the astronauts from a shuttle mission. The name of the instrument used is The Corrective Optics Space Telescope Axial Replacement (COSTAR) instrument (see below i.5). On this spacewalk 5 separate pairs of corrective mirrors were installed and fixed the effects of the flaw ensuring that the imaging would be optimal and as expected upon launch. 

After this fix, the Hubble has been producing amazing photographs ever since and gathered millions of images throughout its life so far. 2020 marked its 30th aniversary and i think that all off us can agree that Hubble will not be forgoten long after it stops serving.