Status Report

NASA Blog: From Gobies to BBots: Hubble’s Marriage of Convenience

By SpaceRef Editor
August 21, 2008
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NASA Blog: From Gobies to BBots: Hubble’s Marriage of Convenience

Could the lack of one thing make this Hubble repair mission impossible? Kaput, never to be? All that would remain for us is a deep sigh and a heartfelt wish to see more beautiful, yet unattainable, pictures of stellar nurseries and sudden, cataclysmic stellar deaths, extra-solar planetary atmospheres, and an exploration of dark energy, the mysterious force pulling our universe apart. Discoveries that would forever change how we see ourselves and our universe now wouldn’t be made. What intense problem would bring work on this last repair mission to a standstill? Politics? Inter-NASA Space Flight Center squabbling? A sudden need for swollen bags of money in a time of national crisis? Additional visits from FBI agents intent on reviewing minutiae while frightening young interns?

None of these answers even come close. Instead of rounding up the usual suspects, we humans must first come to grips with the reality of outer space. We want to conquer new worlds, to expand our sphere of influence and accomplishment, moving ever wider into our environment as victors in our solar system. Yet this homocentric universe view doesn’t even succeed in our nearest neighborhood, low-earth orbit, where we have placed Hubble. We humans are incapable of executing the intricate surgical repair plan for Hubble without serious outside help – robotic help.

Humans have visited Hubble four other times. During these visits to our on-orbit patient, internal surgery was only timidly attempted once. That’s when astronauts John Grunsfeld and Richard Linnehan successfully replaced the power switching station and its rat’s nest of cabling and connectors on Hubble in March 2002.

Major surgery is now required on patient Hubble. For the first time ever, we need to probe the guts inside in order to improve our patient’s remaining, productive days. One of those early surgeons, John Grunsfeld, will be returning to Hubble to perform this more invasive surgery.

The two instruments being cracked open on repair mission 4 are not designed for on-orbit repair. Back in the 1970’s and 80’s, we just couldn’t conceive of astronauts performing even minor internal surgery, so we didn’t build in the capability. In the relentless and unforgiving vacuum of space, human beings alone are just not up to the task, so it didn’t seem possible.

But we can do it with a partner, a marriage of convenience perhaps, but one which comes to the rescue. Robotic tools, fifty new ones to be exact. Although we’ve used tools before, advances in these fifty new tools are akin to advances from an 18th century barber-butcher-surgeon to our 21st century neurosurgeon.

The human being-robotic relationship (or being-roBots – – BBots for short) we are entering is akin to the beneficial symbiotic relationships commonly found among species on our Earth. Beneficial symbiotic relationships are ones in which plants or animals of different species depend on one another for survival. For instance, snapping shrimp and gobies live together in the same burrow on the ocean floor. The blind shrimp rely on the goby’s intruder warning alert to keep them safe, while the shrimp keep the burrow clean of parasites. There are thousands of other examples to be found on Earth.

In the case of Hubble, let’s see why the on-orbit repairs require a similar symbiotic relationship between the astronauts and the robotic tools. Let’s say you have a spectrograph on your lab bench. It is used to split light into all the colors of the rainbow for you, revealing information about its origin, temperature, and chemical makeup.

Now, you’re technically savvy, so you’ve discovered that one printed circuit board within your spectrometer contains a faulty power supply unit, making your beautiful spectrometer dead as a door nail. To add to your task, you have a second instrument on your bench, a camera, and it, too, has a failed power supply unit on one PCB. What would you do? Well, you’d just fix it, right? You’d simply open up the instruments, pull out the faulty boards, replace them with good boards, and put the instrument back together. Easy.

But now things get hairy. Your two instruments are placed in the deep end of a pool. And for the first time ever, these instruments are not designed for you to easily open them and get to the faulty cards while you and they are submersed in water.

So, you’re suited up in scuba gear and dumped into the deep end of the pool in order to perform these tasks under variable lighting, going from adequate to hazy. Oh, and of course you don’t want any of the 143 screws you’ve removed from these two instruments to float away. And you wouldn’t really want to put all those screws back in as you closed the two instruments up. As a diver, I know what would happen to me. With all these obstacles and things to think about, I might suck down all the air in my scuba tank!

Now would be the perfect time to reject the folly of a human being-robot competition and embrace the need for a cooperative marriage, if not from love, then from convenience.

Next week I’ll talk to the tool-master at Goddard, Justin Cassidy. He’ll reveal his favorite tools of all time for the Hubble repair mission.

What next? As Mr. Mordecai Albert says on his August 3rd comment, we all thirst for additional information on Hubble’s contributions to our knowledge of the cosmos.

So my follow-on column will focus on the amazing scientific discoveries – -those “Aha” moments — brought to us by Hubble. I’ll visit the Space Telescope Science Institute and bring you directly to the scientists themselves. I’ll also continue the saga of the young intern and the FBI agents.

Keep those comment coming! It’s a pleasure to have the opportunity to talk to people this way.


From Gobies to BBots – – Part II

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.


SpaceRef staff editor.