Breaking Through

STS-53 Landing

Watching the HUD video during Discovery’s landing yesterday made me think of Dave Walker and STS-53.  The video feed (which is not great quality) showed low clouds obscuring the visual landing aids until fairly low in the final approach.  Probably not a flight rule violation, but then neither was the day I sent Dave to Edwards and there was this one cloud . . .


Dave Walker was a decorated Naval Aviator, and he is no longer with us.  I miss him.  But the most important thing to know is that Dave Walker was a true individual.  One might say he was colorful.  Or a character.  Dave was the commander of STS-53 and I was the Ascent/Entry Flight Director.  That means I had a dog name.  Oh yes.  That was Dave’s idea.

Dave drove an old – I mean really old – station wagon to work and parked it in the lot by building 4.  It was so old that he repainted it white.  It was not a great paint job.  Then Dave found a T-38 wingtip that had been damaged out at Ellington field and was going to be scrapped.  He took it home and affixed it to the top of the station wagon.  He named his vehicle “the dog mobile”.  Yep.  And everybody in his crew and the trainers and flight controllers all got dog names.  Dave was “top dog”.  Jim Voss, one of the mission specialists who was an officer in the US Army was “dog face”.  You get the picture.  Somewhere in the pilot jargon, a “sled” is a really fast airplane.  Since my job involved them flying really fast, I became “sled dog”.  Oh my.  Everybody got a dog name.  If you were lucky you got to ride in the dog mobile.


But he was no nonsense about flying, and we had a big flying challenge on STS-53.  We were going to demonstrate the shuttle autoland system.

The space shuttle had been designed with the capability to autoland without pilot intervention but there were certain . . . quirks . . . in the system.  It was not deemed safe in the early days.  After 40 or 50 flights, it appeared that those . . . quirks . . . had been gradually fixed.  Of course, landing had to be on a runway equipped with special ground equipment.  The MSBLS (Microwave Scanning Beam Landing System) was built especially for the space shuttle.  If you ever look closely at a shuttle landing you might see a couple of small metal buildings painted red and white just to the side of the runway threshold.  These buildings contained the complex equipment to send out a sophisticated radio beacon which would allow the shuttle to navigate safely to the ground.  If it all worked right.  Which might not be the case.  All the shuttle flights before this relied on the eyes and judgment of the commander to fly the final approach and landing.  This required certain weather restrictions, like the limitation that the bottom clouds must be no lower than 8,000 feet above the ground.

A lot of those launch scrubs or landing day wave offs are due to low clouds, or the possibility of low clouds, or the worry about low clouds in the landing area of the shuttle.  Just so the commander can see the PAPI (precision approach pilot indicator) lights in time to adjust the shuttle trajectory if the navigation was in error.  Which MSBLS could do to you.  Until they fixed those, you know, quirks.

Ostensibly, we needed auto land because the shuttle flights were getting longer and longer and there was a real concern (raised by the doctors) that the commander might become disoriented during landing after a long period in zero gravity.  It was a safety thing, we were told.  All of us in the Flight Director’s office wanted auto land to get away from those pesky low cloud rules that kept us waving off.

Dave took the challenge seriously.  We flew the simulators and the Shuttle Training Aircraft a huge number of times with various navigation errors and offsets, problems with the MSBLS or other navigation sensors, visibility restrictions and low clouds.  We developed a set of flight rules to determine when we would attempt an auto land and when we would not, when the commander would take over manually, and when he would let it land automatically.  The real danger lay in a late manual takeover – by definition in a bad situation – where the commander couldn’t get it back to the runway in time.  So we practiced and practiced and studied and analyzed.

About three weeks before the flight General Jedidiah Pearson weighed in.  General Jed was one of those revolving door retired flag officers that seemed to wind up at NASA periodically.  He was probably a great general.  And since his job was at NASA headquarters his main responsibilities were inside the beltway and I am sure he did a fine job.  He was always nice to me.  But I got the real impression that he never really understood what we were up against, never really understood what human spaceflight involved.  Its not like being a fighter pilot commander in the military.  So as much as I liked him personally, his decision at launch – 3 weeks to call off the autoland test rankled me  He said we would never fly a pilot in space long enough to get them disoriented and therefore we did not need the autoland demonstration.

I was really mad, but Dave counseled patience.  Top dog was right.  We flew the flight – it was very successful – until the very end when Dave and I each took a turn and almost crashed Discovery.  For real.

So I guess I can’t quit the story now.

Landing at KSC was no go.  It was perfectly beautiful at the Shuttle Landing Facility, but there was a weather front approaching which had a sharp edge of very low clouds.  We had been watching the weather for hours and this implacable layer of clouds was marching toward the SLF with military precision.  Given the winds aloft, the SLF would be clear and unlimited visibility at deorbit time, and totally overcast at landing time an hour later.  KSC was no go.

At Edwards, Dick Richards was flying weather reconnaissance for us.  Dick was a very experienced shuttle commander and he knew what was OK and what was not.  There was just one cloud in the sky.  You guessed it.  Right over the PAPI lights with a bottom lower than 3,000 feet.  One cloud did not violate the flight rules – we were allowed to have scattered clouds.  And there was a good wind aloft.  No way that cloud was going to stay there for the hour between deorbit burn and landing.  But Dick made it crystal clear – he was NO GO.  Do not attempt to land here, he told us over the radio.

But I was the Flight Director and the decision was up to me.  The weather forecaster and I conferred.  One cloud.  Couldn’t possibly stay there for an hour.  I gave the crew a GO for the deorbit burn.  I thought Dick was going to climb through the radio headset and stop me.

A funny thing happened back in Florida.  That line of clouds associated with the cold front pulled up short, about 40 or so miles north of the SLF.  My weather forecasters couldn’t explain it.  The SLF was perfectly clear at the scheduled landing time.  But the shuttle was on the way to Florida.

And the cloud over the PAPI lights at Edwards?  You guessed it.  It didn’t move; it just grew bigger.  In the debriefing, Dave told me that somebody “had some‘splainin’ to do” over that cloud.  He was right.  I was that somebody.  My boss, the head of MOD, took me aside and said, “3,000 feet is too low”.  He was right.  The weather guys couldn’t explain that cloud either.

But Dave got distracted at a critical moment in the entry and was about 10 seconds late turning the shuttle on its final heading.  Almost over-g’d the vehicle. But he got it back on track and made it through the cloud and landed safely.  Like nothing had happened.  Whew.  Any landing you can walk away from is a good one.

We wrote down several lessons after STS-53.  About clouds and weather; aboutthe use of autoland; about turning on the HAC.

But I still wish Dave had been given the chance to demonstrate the autolanding system.  I think it will work fine.  There were just some concerns about . . . quirks . . . in the system.

About waynehale

Wayne Hale is retired from NASA after 32 years. In his career he was the Space Shuttle Program Manager or Deputy for 5 years, a Space Shuttle Flight Director for 40 missions, and is currently a consultant and full time grandpa. He is available for speaking engagements through Special Aerospace Services.
This entry was posted in Uncategorized and tagged , , , . Bookmark the permalink.

28 Responses to Breaking Through

  1. Mark Simpson says:

    Good stuff as usual Wayne. When is the book due out again?

    • waynehale says:

      Wings In Orbit – the book that a number of us put together for the shuttle program – is coming off the printing press at GPO at the end of this month. Look for it at GPO bookstores, Barnes & Nobles, and Amazon.

  2. Jim Hillhouse says:


    Dave must have been an amazing pilot to fix a 10 second over-shoot at over 300 knots at the stick a heavy glider falling fast. You should write a book; you really should.

    • waynehale says:

      Well, 10 seconds is my rough guess without going back to my files. It seemed like forever. John Shannon was my GNC and I remember him saying out loud: “where is he going?” But the orbiter was coming back with an empty payload bay so it could take more stress.

  3. I’m not sure if the public ever understood the complexity or inherent danger in pressing the threshold going to space with such a huge mass, or the true bravery of all those who assume that risk so our kind reaps the innumerable benefits… thanks for relating the story… one of the folks at KSC said you could tell Discovery had a Navy pilot at the helm on Wednesday — wheels touched down at the extreme end of One Five, so we got to see chute release right in front of the MLP… 🙂

  4. Teddy Ballgame says:

    On the 5th paragraph from the end, I think you meant to say “the shuttle was on the way to California”, correct?

  5. Mike Robel says:

    I remember my father working (leading?) aspects of the autoland system. Mostly dealing with the Antennaes…

  6. Beth Webber says:

    Another engrossing story. I agree with the first poster…you really should write a book!


  7. Charley S McCue says:


    You remind of all the things I’ve learned over the years that no matter how smooth it all appears to us, space flight is hard work and that most people are like the General.

    • waynehale says:

      Spaceflight is not yet like a military operation or commercial air service. It is very hard. I hope that it evolves over time to be easier and more people get to go, but right now it is harder than most folks imagine.

  8. I remember you telling this story over on your NASA blog – thank you for telling it again here – it’s a great story about how weather can trip you up. Living in the UK I know this all too well!!
    I watched Discovery land at the end of STS-133 I did wonder about the flight rules and the cloud cover. I thought it might be bordering on a flight rule violation?

    By the way – When did the green box on the runway get added? I assume it’s drawn around a set of co-ords rather than down to software ‘interpreting’ the shape of the runway?

    • waynehale says:

      For the record, the landing of STS-53 violated no weather flight rules. The rules were and still are that scattered clouds (less than 4/8 coverage) is a go condition no matter what their height. Requiring perfectly clear weather would result in few shuttle landings . . . .

      There is a green outline of the runway but more important is the green box you see on the HUD which is the “flight director” which is the indication to the pilot of where to point the nose of the shuttle. If you treat landing the shuttle as a video game, the object is to always keep the green x inside the green square. But that presumes that onboard navigation is accurate – generally true, but not necessarily. Especially prone to errors without MSBLS (and these days, without GPS).

  9. Charlie Barber says:

    All; videos of the landing here…

  10. Jonmark Stone says:

    “you could tell Discovery had a Navy pilot at the helm”
    Even if Lindsey was… that would be Naval aviator. 🙂

    Thanks for your blog Wayne.

  11. Andy Foster says:

    Really nice story, Wayne. And you are right that everyone had to have a dog name. I was the contingency abort instructor and became Desert Dog (because of my penchant to run off backpacking in the desert southwest). To this day, my buddy Larry Manofksy (whom I believe was the control/prop instructor for the flight) and I correspond using our dog names. His was “Big Dog”.

  12. Howard G. Law III says:

    Deepest thanks for telling this story. I believe elements of the auto-land work found their way into the Air Force unmanned space plane i.e. X-37. You were most diplomatic on the general. I had to point out to him the differences in the auto-land problems on aircraft carriers and what we were dealing with. I shared your disappointment but hope this is one of those “all things work together for good to them that love God ….” events or non-events.

    Again deepest thanks for telling this story.

  13. David Witwer says:

    Thanks for writing your stories, Wayne. This one is excellent. Looks like Steve and crew broke out at about 3000 ft.
    STS-133 landing videos are linked below with the HUD video starting at about 2:00 minutes:

  14. Viet Nguyen says:

    Like you (and Howard Law in the post above), I was disappointed to see the Autoland DTO scrubbed by Gen Pearson. To prepare the crew for the DTO, I was fortunate to have had the opportunity to give Dave and his pilot Bob Cabana a tutorial of the Autoland system, then together with Howard Law take them through a dedicated training session at the NASA Ames Vertical Motion Simulator – focusing on late manual takeover techniques.
    Although Dave did not like the prospect of a computer landing the Shuttle instead of himself, he was a real professional and took the challenge seriously. I remember him showing up at Ames with a gismo that allowed him to hang his left hand right above the Pitch and Roll/Yaw PBI’s (push button indicators), with his fingers ready to push them PBI’s for a quick manual takeover — and he named it C.R.A.S.H. (I don’t quite remember what the acronym stands for, but the meaning is obvious — “if I don’t intervene, we are going to crash”). In return for my effort, he graciously gave me a ride in the STA in one of his trip out to Edwards.
    I looked at the STS-53 HUD video and it seems that Dave was comfortable enough with the HUD to not declutter it until he broke through the cloud. So all that training maybe was not for naught.
    The Shuttle Autoland would have worked, as Howard Law pointed out in his post above.
    Thank you for writing your blog and share a lot of great memories. The Shuttle is a wonderful flying machine.

  15. I enjoy reading this blog so much. Please keep it up. I’d love to hear more about how your early life prepared you (or left you unprepared) to deal with the issues you encountered at NASA. For example, I’ve heard through the grapevine that you were/are a Scout (Eagle perhaps?). I wonder if and how that affected decisions you made at NASA.

    Really enjoy your writings. Looking forward to the book!

  16. Kirk Griffin says:

    The story about Topdog is great, I also remember his car in the Bldg 4 parking lot and explaining to the masses that it was just Dave. I sailed with him and “Capt’n Blye”(Neil Hutchinson) for years and greatly miss his abruptly honest candor no matter what is going on around you. Thanks to you, and what you accomplished during your time at JSC. Keep up the blog, it keeps reminding the world that manned spaceflight is both dangerous and fun/exciting all at the same time.

  17. Markus says:

    In my mind, he’s always Red Dog (his name on STS-69), and for some reason I’m thinking “Woof, Red Dog!” to myself every year around April. In about a week from now, it’ll be 10 years since he died.

  18. To bad we never got to test the autoland. There are a lot of things a human can do better than a computer. Landing in conditions of poor visibility is not one of them. We can’t risk a billion dollar airplane just to show we are hot sticks.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s