Wayne Hale's Blog

Not open for further replies.


Could not resist posting this one.

Thanksgiving Memories Posted on Nov 24, 2009 08:44:29 AM | Wayne Hale

The shuttle is in flight once again this Thanksgiving Day, not the first time a holiday has come during a shuttle flight. My station friends remind me that they fly 24/7/365 and Christmas is really just GMT day 359. But when the shuttle is flying during Thanksgiving, I am always reminded of one significant day:

STS-33 was one of those classified DoD shuttle flights we can’t really talk about. But I don’t think I’ll be in any trouble with security over this mostly true story. I was the Orbit 1 team Flight Director and the shift schedule called for my team to be on console about noon. We had a big family Thanksgiving meal early that year (a real challenge for my wife). Satiated with turkey, all the trimmings, and pie, I arrived at the MCC to start handover from the planning team lead by Rob Kelso. We were expecting a really quiet shift.

Falcon Flight gave me the big news before I even plugged my headset into the console: “Potty is broken!” Sigh. Flight Directors spent hundreds of hours studying the various systems: engines, fuel cells, navigation. Everybody’s least favorite system was not working. “If we don’t get it fixed, the crew will have to break out the Apollo bags” Rob continued. If you don’t know what an Apollo bag is, well . . . let’s just say that you really didn’t really want to know. It’s a big plastic bag with sticky substance on the lip which you apply to your . . . anatomy . . . to take care of your . . . business. Not glamorous.

Fixing the potty is not exactly the kind of problem you want to work on following a big meal.

So MC finished team handover, got a few sketchy details from the crew, and set to work to see how the “Waste Management Collection System” could be fixed.

It wasn’t until the post flight debriefings that we heard what really transpired onboard. Story Musgrave, raconteur extraordinaire, was an eyewitness. It seems that the victim of the WCS failure was the commander, Fred Gregory.

First, you must have a primer on how to go to the bathroom in space (every schoolboy’s favorite subject). The lack of gravity means that everyday earth based technology does not work. Early efforts were primitive (reference the discussion of the Apollo bags above). #1 might be easily taken care of, but #2 is a much bigger problem (Pardon me here, my vocabulary is influenced by the recent effort to get my grandchildren potty trained here on earth). Without gravity the . . . waste material . . . tends not be removed from the body. The shuttle potty deals with this mainly by airflow. A very small opening in the toilet (much smaller than earth based toilets) allows just the critical part of . . . your anatomy . . . to fit precisely over the hole. There is a famously closed circuit TV in the WCS trainer at JSC’s building 5 to help astronauts learn how to correctly position themselves. Flight Directors did not have to go through this little indignity during our training. In early WCS designs, there was a complicated mechanism down that hole called the “slinger/shredder” which was pretty descriptive of its intent. The astronaut office objected to having a high RPM mechanical device so close to . . . . their person . . . and tests showed that the “slinger/shredder” probably wouldn’t work well, so the design got changed early in the shuttle. Now the toilet just uses airflow to do what gravity does here on earth. One sits in the WCS compartment with your feet in stirrups and a lap belt to hold you down. Once correctly positioned, the victim uses a handle much like an automobile gear shift lever to start the mechanism. First pull on the lever closes the vacuum valve – all the odors in the quiescent potty are sucked out through the orbiter’s overboard vent system. Second pull on the lever opens the “slider valve” just under the seat and that means the toilet is open for . . . business. Next pull starts a small fan which circulates air to help with . . . removal. When you are done, reversing the gear shift lever first turns off the fan, then closes the slider valve, and finally opens the vacuum vent. In that order.

Some quirk of sadistic spacecraft design required that all the air coming into the space shuttle crew compartment comes in through the “roof” of the WCS compartment. Normally there is very little makeup air required, but when the pressure falls slightly due to the natural leakage of the crew compartment, makeup air flows in through automatic valve outlets. A sophisticated system automatically keeps track of whether the makeup gas should be oxygen or nitrogen, the desire being to maintain a sea level atmosphere composition and pressure. Since the crew breaths in oxygen (and the exhaled carbon dioxide is removed elsewhere), the makeup gas is usually oxygen. The cryogenic oxygen tanks in the payload bay feed both the fuel cells and breathing air. The liquid oxygen from the tanks must be warmed to become a gas, but it still comes out very cold in the WCS compartment.

So during crew sleep early Thanksgiving morning, Fred Gregory had to do what comes naturally. All was well until (as) he moved the gear shifter to close up the WCS. Story related what happened next with great relish. Unfortunately, somewhere in the mechanism, the slider valve failed to close - but the vacuum vent was opened up! Depressurization! You can imagine what it would be like to be strapped down, have the suction of pure space applied to . . . . your person . . . , have a rush of cold oxygen burst in over your head, and the depress Klaxon alarm going off simultaneously.

Story opened the WCS door and together they got the mechanism to close the slider valve, and then got Fred off the seat.

Of course the whole crew was awakened by this commotion and John Blaha, the pilot, was starting to work the emergency procedure for cabin leak.

The immediate danger passed, but Mission Control was now on the radio and wanted to know what happened. A much abbreviated narrative was received. Needless to say, not much sleep was had for the remainder of the crew sleep period. And the bathroom was definitely closed for maintenance.

On the ground, MCC called in the engineering team that designed and tested the WCS (remember, it’s a holiday and most folks were just then sitting down to the Big Meal!) We got a crew of techs to open up one of the WCS units on the ground. Meanwhile, the flight controllers studied systems schematics and flight rules. We all pondered how to make the thing work. The IFM (in-flight-maintenance) guys came to our rescue. By removing the cover from the front of the device and applying vise grip pliers to an appropriate lever, the potty could be used without depressurizing the cabin again.

Whew. Problem solved. That’s what MCC is there for.

Every Thanksgiving now, sometime after the pie and before the football game/nap, I chuckle as I remember that episode. And give thanks for 1 G and three toilets in my house.

A few days later, Fred Gregory tried to land the shuttle like he did the T-38 . . . but that is another story for another day . . . .

Happy Thanksgiving!


honestly, we are simply going to provide some kind of gravity in ships flying around our solar system (when that happens). We have to learn to spin our ships, all this money spent on learning how the human body works in micro gravity is bunk.

Lets be clear, our bodies dont work in micro gravity no matter how many tests you do. Lets stop that and start to spin ships. Either spin your ships... or spin your shits... but something has got to spin before this is all over.



Amusingly put. :lol:

Rotating ships are, ultimately, the way to go. It's a real pity the centrifuge accomodation module for Columbus aboard the ISS was cancelled; it would've been very helpful for researching the issues associated with that.

One big problem is figuring out how big the centrifuge needs to be to produce effective gravity without making everybody just as sick as microgravity does. The initial data seems to suggest "bigger than we're likely to manage at the moment". :( Although, I do like the concept of having a small spacecraft attached to a counterweight via some sort of tether. That gets around the size problem.


Reminded me again what a technical marvel the shuttle is .

Thanks for the post.


Are YOU up to making the call?

Time to Closest Approach Posted on Dec 09, 2009 12:16:45 AM | Wayne Hale

Being at a conference on Orbital Debris has turned my thoughts back to being a Flight Director and experiences I would rather forget.

There is a lot of junk in earth orbit, and some of it endangers our astronauts every day. Paint flecks and particles of solid rocket exhaust are big enough to damage the shuttle windows. We now replace the shuttle windows every flight because of the damage that these microscopic particles cause.

At 5 miles per second, there is a lot of energy in “collisions” between orbiting objects. Every bit of space junk packs the equivalent of 25 times its weight in TNT because of the extreme speeds of orbital encounters. We cannot track the small stuff. Even pieces as big as loose bolts are untrackable and potentially fatal. A one inch bolt in orbit could punch a hole right through the shuttle or the station causing huge damage and explosive decompression. You don’t even want to think about what it would do to a spacewalker in their fabric suit.

Larger items are tracked by NORAD (they have a new name but I never remember it). We know where the big pieces and can avoid them. Or so you might think. There are limits to how accurately the trajectories of space junk can be determined. Trajectories are affected by the solar wind, transient and unmonitorable variations in the upper atmosphere, and some objects even have propulsive vents so their trajectories are constantly and irregularly changing.

The shuttle, of course, is always maneuvering and changing attitude. The shuttle thrusters are not completely symmetric so there are small changes to the shuttle’s trajectory every time they fire.

Orbital trajectories are predicted into the future assuming none of these variations. Even so, the very small uncertainties in a trajectory gets multiplied over hours of prediction and this leads to a grey zone surrounding its predicted future position where the space object may or may not be.

Nowadays this is a sophisticated science with much better tools. Better radars and lots of mathematics and probabilities give a much more complete notion of where and when encounters may take place.

In the early days of shuttle we just knew that anything predicted to come within a few miles could be a hazard. Missing by inches is OK; missing by a mile is good; but it was all like Russian roulette in those days.

Knowing how to maneuver to avoid a predicted “conjunction” is critical. If you guess wrong and maneuver to the part of the uncertainty box where the space junk actually is: POW. Sometimes doing nothing is the best option.

Operationally there are other impacts. Since shuttle maneuvers are initiated by the crew, obviously the crew must be awake to maneuver the ship. If the crew sleep is interrupted, their performance the next day may be affected. Think about being awakened in the middle of the night to do a precise task and then trying to go back to sleep, wake up the next morning at the regular time, and have a big work event that day. Not really good.

So the early shuttle it was thought that we should not wake the crew up for debris avoidance maneuvers. Even though space junk was predicted to be coming close by and could hit us, the odds were in our favor for a miss. In the cold calculation of the risks involved it was thought better to let the crew sleep rather than wake them for something that might not happen. We codified this in the Flight Rules.

On exactly three occasions I was the Flight Director on the crew sleep shift when we got the word a “conjunction” was imminent. I remember each event like it was yesterday with crystal clarity. Some things do not leave you. I made all the appropriate notifications; phone calls to the management confirmed that we should follow the rules, let the crew sleep, and bet on the odds in our favor.

So GC would set a clock on the big board counting down to “TCA”. Meanwhile we all tried to do the mundane work of monitoring the shuttle systems and planning the crew’s activities for the next day. On the assumption that there would be a next day.

But as the clock counted down close to zero, Mission Control would get very quiet. We all knew what might happen. It’s tough to sit on your hands when your friends are in danger and you can’t do anything about it.

In my imagination, the worst case scenario played out: instantaneous cessation of telemetry transmission from the shuttle followed some time later by NORAD tracking confirming a multiple pieces in an orbit where only the shuttle had been before. Then the notifications, the investigations, the whole drawn out parade of mourning and recrimination. I could see it all.

So as we waited for the clock to count to zero, there was plenty of time to contemplate metaphysical topics: life, death, courage, risk, achievement, probability, dishonor. They are all fellow travelers, intimately bound together. No great accomplishment comes without difficulty or risk. Miscalculation or failure results in death and dishonor. But it is what it is; you do the best you can, make the best rational choice you can given what you know, and then wait for the result.

Going to Las Vegas holds no enticement for me.


Talk about Russian Roulette. *shivers* I'm glad I'm not in that line of work.


Predictions and Wishes Posted on Dec 24, 2009 09:00:14 AM | Wayne Hale

At a recent speaking engagement, I was introduced as an “expert”. Scary title, that. At another place I was introduced as "highly experienced" which is a polite way of saying "old".

These put me in mind of Clarke’s Law. Sir Arthur C. Clarke, the inventor of the geostationary satellite, author of innumerable books both non-fiction and science-fiction, and one of the truly forward thinkers of the 20th century. Clarke’s first law has to do with predictions and experts. He came to an interesting conclusion after studying the predictions of experts over the previous centuries. To get you in the right frame of mind, consider some of these real predictions by well respected experts of the past:

Rail travel at high speeds is not possible because the passengers, unable to breathe, would die of asphyxia – Dr. D. Lardner, 1835

I can accept the theory of relativity as little as I can accept the existence of atoms and other such dogmas – Ernst Mach 1912

Our future discoveries must be looked for in the sixth decimal place – Nobel Prize laureate A. A. Michelson, 1894

Aerial flight is one of that class of problems with which man will never be able to cope – Simon Newcomb, 1903

The [atomic] bomb will never go off, and I speak as an expert in explosives – Adm. William Leahy to President Truman, 1945

The popular mind often pictures gigantic flying machines speeding across the Atlantic carrying innumerable passengers in a way analogous to our modern steam ships. It seems safe to say that such ideas are wholly visionary and even if the machine could get across with one or two passengers, the expense would be prohibitive to any but the capitalist who could use his own yacht. – William H. Pickering, 1910

And so on. You get the point, and there are plenty of other predictions we can laugh at today.

So Clarke postulated his first law:

“When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

Everybody is making up Christmas lists or maybe New Year’s Resolutions and wishes for what might happen in 2010 or later. I think I will avoid such lists.

In hopes of proving Sir Arthur Clarke correct, and based on my status as an aging “expert”, I would like to make some predictions (tongue firmly planted in cheek – hoping that reverse psychology will make the predictions fail):

1. Human spaceflight was a passing fancy and its disappearance will hardly be noted by historians nor missed by the general public.

2. Human beings will never again set foot on the moon nor travel to Mars or any other celestial body.

3. The study of engineering and technology will become a thing of the past as the world’s standard of living returns to that of the 18th century.

4. The popular entertainments of the day will so capture the imagination of the public that they are rendered incapable of any real productivity and spend their time in the pursuit of gossip about actors and sports figures.

5. Constant exposure to digital toys will decrease the human attention space to milliseconds preventing any useful thought or accomplishment.

6. Without any unifying goals, the world becomes increasingly balkanized into clan-like groups who turn to violence over ancient insults, real or imagined.

OH NO. What an awful set of predictions. The Grinch or Ebenezer Scrooge could not have done better. But there they are, and I want credit for having made them. If they come true, then I should be remembered for having predicted them. If they don’t come true, I’ll be just as happy to join the company of William Pickering and A. A. Michelson!

Now for what I really wish for at this season (not a prediction, lest I jinx it!):

A commitment from all the space faring nations of the world to join together – with adequate resources – to explore in detail the entire solar system in our lifetime; including the first permanent human habitations (colonies) on the Moon and Mars and outposts at other strategic points in the solar system; a well established and effective transportation system to link this community together; and a strong technology development program to enable it all. Such an international effort would unite the peoples of the earth in cooperation to achieve a historic and noble goal and would result in innumerable benefits from technology and medical advancements, stronger economies and new industries, and serve to inspire our children to study the hard subjects and to follow their parents in achieving great things.

This may be too much to wish for; some may call it unrealistic, but human progress has only been truly made by unrealistic people. Now my wish is that we buckle down and do it!

My very best wishes for each of you to have a Merry Christmas and Happy New Year!


It rather belatedly occurs to me that these postings exceed the limits for Fair Use. We should post only short excerpts (teasers, if you will) and a link to Mr Hale's blog where folks can get the rest.


Life is full of gray choices. Deciding the work completed is good enough because more will not make it perfect. Ten thousand gray choices; doing what we must do, and not a bit more because that would take away from other work that is absolutely critical to be done right. When we have done what we can do, when we have driven the risk to the lowest practical level where it can be driven, then we have to accept the fact that it is time to make a decision and move on. Because history is waiting for us. But history will not wait forever, and it will judge us mercilessly if we fail to face tough choices and move ahead.

Just a teaser Go look for the rest. I'll try Callli but may slip.



Ad astra per somniis

Short note today; I am at the Suborbital Research conference in snowy Boulder, CO.

I am surrounded by dreamers who want to fly in space: everybody from Lori Garver and Alan Stern on down to the grad students who is here wants to fly in space. They desperately want to fly in space.

http://blogs.nasa.gov/cm/blog/waynehale ... l#comments


High Culture and Spaceflight

Tennyson’s Ulysses (1842):

Come, my friends,

‘Tis not too late to seek a newer world.

Push off, and sitting well in order smite

The sounding furrows, for my purpose holds

To sail beyond the sunset, and the baths

Of all the western stars, until I die.

It may be that the gulfs will wash us down;

It may be we shall touch the Happy Isles,

And see the great Achilles, whom we knew

link http://blogs.nasa.gov/cm/blog/waynehalesblog
Not open for further replies.


Latest posts