Rocket Scientist

It is serendipitous that I check out Gumby the Science Cat’s blog every day.  Here I was talking about manned and unmanned space and, long-windedly, pointing out they need to work together when one of the best examples of this makes the news again:   Hubble.  I’ve been working on other stuff all day so I hadn’t noticed, but Gumby came through for me.

As a strange coincidence, this is a topic I know, and in depth.  You see, I was the EVA (Extravehicular Activity) Safety Flight Lead for the last two Hubble Servicing missions.  So, let me start by saying this: Hubble, the jewel of the unmanned space programs, loved by all, owes everything to our manned spaceflight program.  There, I said it.

If you’re the kind of space nut that does more than download the fabulous pictures (and you can find some gorgeous photos from many NASA archives here, well worth the visit) from Hubble, you probably know about the lens problem that needed to be corrected on Servicing Mission 1.  You may or may not know about the gyros that have sent Hubble into safe mode before.  All have been replaced more than once and we’ve had a hurry-up mission to save the Hubble before.  Servicing Mission 3 became Servicing Mission 3A and 3B, the last two missions.  We’ve also lost a transmitter we never intended, had circuitry fry because of overheating on the batteries, replaced a power control unit (and that was one heck of a task), replacing thermal shielding, recovering peeling handrails and install cooling systems that had never been intended to keep science instruments running.

Now, let me also be one of the first to say that the Goddard Hubble folks are some most dedicated and creative minds out there at NASA.  They manage to tackle many problems that had never been foreseen with original and inventive corrections that, time after time, work just like they’re supposed to.  Tools get changed on the fly, new ways of reaching or cooling or grasping are devised so that our crewmembers can do the near impossible.

But the EVA crewmembers are fabulous.  On both flights I worked, the EVA crewmembers (two teams of two) were astounding and I was continually impressed with their acumen, their dedication and their skills.  And, on Hubble, you need every skill, every brain cell you can get.  The tasks are difficult, with tight schedules and spaces and many delicate instruments and surfaces that can’t be touched or jostled or exposed to light.  In some cases, one crewmember will hold the legs of the other as he disappears half-way into the bowels of the telescope.  They have specialized tools, tons of them, they don’t use anywhere else on dozens of carriers and storage units.  [As a frame of reference, there are 54 pages of acronyms for the Hubble Space Telescope alone].  There are always more tasks than time, upgrading support equipment, like the data recorders, solar arrays and, for the next flight, batteries, swapping out instruments and, of course, repairing what has gone south since the last flight.

EVA’s are practiced in the Neutral Buoyancy Lab (NBL), no less than ten times for each activity they’ll do on orbit, more than average because they have to be carefully choreographed or there just won’t be time for it all.  Extra days (contingency days) are usually filled to capacity as well in case the opportunity comes along to add another EVA.  Believe me, it will be put to good use.

Well, today something else broke, the data handler that sends the scientific information down.  Fortunately, there’s a spare, but switching it is a nontrivial task and it hasn’t gone live since the ground testing 20 years ago.  If it works, we get more from our telescope.  If it doesn’t, we won’t get any more from Hubble until the servicing mission goes up, which has just been delayed until at least next year.  Why?

Well, even if all goes well, they might want to replace the broken part, or we’re just one failure away from losing the Hubble’s science for good.  But, to do that, there are some things to do:

1. Roll back to VAB.  Other flights will have to go.  The schedule’s tight and we’ll need to reconfigure the payload bay.
2. Rework the crowded EVA schedule (which may mean dropping another precious task) to fit the rework.
3. Train the crew in the new task.  That’s a lot of work which may require building a mockup, planning a task, possibly building new tools, working it in the water perhaps a dozen times.
4. Evaluating the new task for hazards.  All that certification and safety review was likely complete.  Now, the new task will have to be evaluated as well.
5. Testing and certifying the replacement.

We’re lucky we had the opportunity to address this.  The timing of the failure was fortunate.  Just remember, when we enjoy the beautiful pictures and new discoveries Hubble has in store for us the next few years, who made it happen.

Thanks, astronauts.  We owe you.