Bob Mosley Flying Convair 990
Shuttle Dead Stick Tests
One little flying “goodie” came my way quite unexpectedly, having to do with the design of the Shuttle, i.e. whereas the original thinking was that the Orbiter would have a couple of fold out jet engines on it to assist it on it’s landing approach, after coming back from space, the thinking changed to consider eliminating the engines and land it as a lifting body (no power) which NASA and the Air Force had been doing some experimenting with. The Air Force decided to foot part of the cost of NASA, modifying a commercial type airliner, with an automatic landing capability, and program it to fly a simulation of the flight path an orbiter would make on it’s landing approach after returning from space, as part of this investigation of making “dead stick” landings” (as opposed to the fold out jet engine approach being planned). Since the AF was putting money into the program, they insisted they have a test pilot of their own in on the project to assist in the evaluation. I was selected to be that Air Force test pilot. It was a very interesting test and I would have never considered something like it, happening to me that late in my career.
Very briefly the test consisted of taking this modified Convair 990 airliner up to 40, 000 feet and there you would put the gear down and speed brakes partially open, reduce the power to basically idle and then, either using the yoke or a hand controller, keep two needles centered (much like an ILS approach) and the plane was programmed to give you a flight path and rate of descent simulating the orbiter’s planned flight path on an approach. At completion of the approach, still keeping the needles centered, it would give you a nice landing (on most tries). The other capability was to establish the drag configuration at the aforementioned 40,000 feet, as above, and punch in some numbers and it would fly the whole approach and landing automatically (you just sat there and watched). The pilot’s contribution was to see how reliable the equipment was and of course make the needed corrections to keep the plane from crashing when the programmed inputs did not work out correctly. One thing it did fairly consistently was to come in too fast and you would have to take over manually and hold the plane off from touchdown so as not to exceed the tire limit touch down speed of 175 knots. This was no problem because we were doing this testing on the 15,000 long runway at Edwards AFB. ----- We were using about a 12 degree glide slope on these approaches, and whereas the Orbiter ended up using about an 18 degree glide slope, 12 degrees was a fun ride also, for a change.
It was a most interesting little bonus assignment for me, and the results of that test were instrumental in changing the design of the orbiter to make “dead stick” landings, as it did/is doing throughout it’s life time (as opposed to using heavy fold out jet engines for making the approach as originally planned).
Below are significant pages from the Test Flight Report I wrote:
The First Orbital flight was in 1981
Once a bunch of Russians visited KSC, and in the typical American "Good Guy" roll, KSC told them everything they wanted to know about the Space Shuttle (that we knew at that point). I was told that among everything else they took, was a copy of my test report. Believe that or not, but that is what I was told.
NOTE: Fortunately, the "Piggy Back on the 747" concept negated the need for the horizontal and ferry flight testing, as mentioned above. I still have the test flight plan I wrote to do these planned horizontal and ferry flight tests of the orbiter here at Kennedy Space Center ( KSC), using attachable /detachable jet engines. YES, there was serious consideration (at least by the Director of the Space Shuttle Program at KSC) given to building the Orbiter here at KSC, and if the Grumman Co. had gotten the contract to manufacture the Orbiter instead of Rockwell International, it may have very well worked out that way. It was that line of thinking that caused the Director of the KSC Space Shuttle Program, to direct me to write the " straw man" Horizontal Flight Test Program mentioned above.
Robert L. Mosley
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