Source: BBC
Happy birthday, Hubble. It’s 20 years since the shuttle blasted off from the Kennedy Space Center to place the famous observatory in orbit.
The telescope’s achievements are immense. Few instruments in the history of science have had quite the same “wow factor”; and anyone who looks at its iconic pictures cannot fail to question – just a little bit – their place and significance in the grand scheme of things.
As we’ve come to expect on such occasions, Nasa has released a suitably stunning image to celebrate the birthday.
The photo shows just a small portion of the Carina Nebula, a colossal birthing cloud for new stars in our galaxy. The pillars of dust and gas which dominate the scene are about three light-years long. Amazing.
The version rendered on this page uses data acquired by Hubble’s Wide Field Camera 3, which was installed on the last shuttle servicing mission and promises a raft of further discoveries as the telescope moves into its twilight years.
How appropriate that Hubble was launched on the “Discovery” shuttle. Its commander for that mission was Loren Shriver, with whom I managed to exchange a few words this week. The deployment mission sticks out in my mind because of the issue Loren and his crew encountered with one of the solar arrays.
These panels were supplied to Nasa as part of the 15% European contribution to Hubble and were manufactured in my home town, Bristol, at BAe.
So as you can imagine, there was much pride in that fact… but also a little consternation when the roll-out of one of the arrays didn’t go quite as planned.
As Loren recalls, the problem had nothing to do with the arrays themselves, but rather an error in the software managing the unfurling process:
“It all came down to a sensor and a software routine. If the sensor sensed that there was too much tension being placed on the array when it was being unrolled then it would cut off the motors to try to prevent any damage to the solar array. It turned out the software routine was the culprit. It was getting triggered somehow and cutting off the motors when indeed there was no excess tension. Someone worked it out in the end, and a command was sent to the computer from the ground to bypass that part of the software; and then the solar array rolled out to its full extension.
“But you know, we had Bruce McCandless and Kathy Sullivan suited up in the air-lock ready to go out and do the job manually. They were almost at vacuum in the air-lock and another five minutes they would have been outside. As a consequence, of course, they missed the release of the telescope because we did it almost immediately.”
I promised I would occasionally dig around in the BBC archive for items of interest, and on this special occasion I’ve pulled up the former BBC science correspondent James Wilkinson’s report on this solar array roll-out incident. James catches perfectly the drama of the moment.
To read more: http://www.bbc.co.uk/blogs/thereporters/jonathanamos/