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We left patient Hubble last week with a few unanswered questions. We rejected the folly of a human being-robot competition and embraced the need for a cooperative marriage, if not from love, then from convenience, between humans and robots. Now, let’s meet someone at Goddard who designed the surgeon’s robotic tools those astronauts will use on our patient.
In this brave new world, the engineers at NASA’s Goddard Space Flight Center joined with astronauts and engineers from Johnson, Kennedy, and Glenn, among others, to develop the robotic tools required for Hubble repair. There are about thirty-five engineers at Goddard who have designed more than fifty tools ready for use on this fifth and final mission to Hubble. These tools are not usually thought of as “robots” but they are a step along the evolutionary path to robots in space.
One man has been designing Hubble repair tools for the last four years – – Justin Cassidy, Crew Aids and Tools Lead Systems Engineer. What are his favorite tools of all time? Not even needing a moment to consider, Justin said “My clear favorites are the two tools that make the STIS or Space Telescope Imaging Spectrometer surgery possible: the mini-powertool (power screwdriver) and the fastener capture plate.”
Without the high-speed, low-torque power mini-powertool (210 rpm +/- 30 rpm with up to 5 ft-pounds of torque), accessing 1 of 13 printed circuit boards inside of STIS would be incredibly difficult and worse, time-consuming for the astronauts.Now, the 111 screws holding down the cover of STIS can be removed by an astronaut in about 20 minutes.
As Justin put it “We humans control the evolution of our tools, and the Goddard Space Flight Center has stepped up the pace of that evolution for this last Hubble repair mission. We have created many tools to make never before repairs to instruments.”
But NASA employees are not satisfied until the best evolutionary path is found. Qualifying (testing) a new tool in space is a necessity. The battery and electronics for the mini-screwdriver must withstand the harshness of space because of the extreme temperature fluctuations and airless environment. But after Justin and his group surveyed industry to find a battery for the mini-powertool, they realized the solution was in their own back yard. Goddard had designed the PGT or Pistol Grip Tool for the first Hubble repair mission in 1997. It was a low speed, programmable high-torque power screwdriver and its battery was already flight qualified. Reusing the PGT battery for the mini-powertool saved both money and time for the team.
Justin’s next favorite tool is the smartly designed fastener capture plate. Those 111 screws need to be secured somewhere so they don’t float around after they are removed. The fastener capture plate has a place for each screw, neatly color-coded in red-white-and-blue, yet see-through, so the astronauts can easily see what they’re doing. Goddard called on experts in material coatings from GSFC and the Glenn Research Center to make sure all the materials used on the plate and see-through windows could withstand the thermal extremes in space and that the material wouldn’t “outgas” or release contaminants while used inside HST. Outgassed material can be a major source of contamination, something every kid with a telescope on the ground knows would ruin her telescope mirror and along with it, her images.
Of course, you don’t want the surgeons to stitch up the patient by putting back all 111 of those carefully captured screws, inefficiently using valuable EVA time. The engineering solution to this problem is not straight-forward. The cover to STIS provides an avenue for heat to leave the instrument and go out into space and this capacity is essential to the thermal control of the instrument itself. So the engineers at Goddard developed a nifty cover that provides the thermal conductivity while it easily snaps into place on top of STIS with two large latches.
Although Asimov and other heroes of science fiction can take you to the future, for now, Robots have no independent thought, no independent soul from their human being masters. Today, they are hand-held tools. Tomorrow, there will be a marriage between beings and robots — something that might be called Being-Bots or BBots.
So we have now gone from symbiotic Gobies and their interspecies mates (see August 13th blog), to BBots, joining beings and robots in a quest to explore outer space.< The gap between fact and science fiction is collapsing.
I hope you’ve enjoyed this journey into Hubble repair mission 4 tools and how they are one small step on the evolutionary pathway to robots and humans working together in space.
Colleen