Elvin F. Knotts -- NASA Years

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Elvin Knotts spent several years working for the Space Industry.  He started working for North American Aviation in 1959.  Even after retiring in 1990, he served as an aerospace consultant on the Space Station contract in 1991.  During those 32 years, he worked a lot of projects and had many successes.   He gained the respect of his peers and was known as an honest man and a diligent worker.  Some of his accomplishments are highlighted here:

• Apollo Program:  For the Apollo project over at eight-year period, performed trajectory, guidance and subsystems design studies including trajectory program development, entry trajectory design, TPS design trajectories development, formulation and implementation of a roll response model, entry guidance algorithm formulation, Entry Monitor System concept definition and development, and Data Priority meetings support.  The Data Priority Meetings were used to decide how to use the available Apollo systems to go to the Moon and return.   Elvin Knotts was a Rockwell representative to these meetings which were attended by the astronauts and discipline specialists.  Elvin Knotts said that working with Mr. Armstrong and Mr. Aldren, the first men to land on the moon, and Mr. Collins as the first lunar landing was being planned was both an honor and an unforgettable experience.    (See pictures below.)

• Mars and Venus Aerobraking: Developed techniques for using the atmosphere to do aerobraking so as to place a vehicle into orbit around the planets.  (Note: The aerobraking procedure, sometimes called aerocapture, was recently used to place the Global Surveyor into orbit around Mars.)

• Entry Guidance Monograph:  In concert with a fellow worker authored a guidance monograph for the atmospheric entry flight phase, one volume of a 17 volume series completed for the NASA.

• Space Shuttle Design and Development:   Participated in the preliminary design, the proposal, and the design, development, test, evaluation, and operation of the Space Shuttle including development of a Simplified Thermal Protection System (TPS) Model.  Worked as a team member to design the TPS system, formulated and implemented an entry guidance algorithm, and selected trajectory profiles for the operational Space Shuttle missions.

• Air Force Shuttle Operations and Planning Complex (SOPC):  During a two-year Phase B study with five other companies, served as Project Engineer for the Flight Planning Element for the Air Force's version of the Space Shuttle which was destined to fly in polar orbits.  Duties included the selection of the computer systems to do the planning, staffing requirements, security concepts and requirements definition.  Prepared several high level briefings and presented them to the Air Force.

• Shuttle Transportation and Operations Contract (STSOC):  For five years served as manager of the Descent Group that did all of the flight planning for the atmospheric entry flight phase from deorbit to touchdown.  The products included both the planned atmospheric entry profiles as well as all of the entry profiles resulting from an abort during ascent into orbit.  This work was done as an extension of NASA and the products were used to actually fly each Space Shuttle flight.  (See pictures below.)

Elvin Knotts' Greatest Technical Accomplishments:

• Entry Monitor System (EMS) Concept Definition, Design and Implementation for the Apollo Program:  The Apollo Command Module had only one computer.  The primary guidance commands during entry came from this computer.  If the computer were to fail while returning from the Moon, the astronauts would not know how to maneuver the Command Module to avoid either a super-circular skip out of the atmosphere or excessive loads which could easily exceed 12 g's, either of which would be catastrophic.  The challenge was to find a simple yet workable way to monitor the primary guidance for approach to critical flight limits and if these limits were reached to provide guidance information so that the astronauts could reach a suitable ocean landing site.  Elvin Knotts and two colleagues came up with a simple solution to a complicated problem that satisfied all of the requirements.   Because Cathode Ray Tube (CRT) displays were not flight qualified for use on Apollo, a mechanical display device was used.  The resulting device consisted of a scroll of mylar upon which certain monitoring lines were etched.  (Finding out how to draw the monitoring lines was the key that made the concept workable.)  To provide speed information, the scroll was driven from right to left across the face of the display, somewhat like one of the old Brownie cameras; to give load factor information, a pointer was driven up and down.  By comparing the speed vs. load factor trace to the critical monitoring limits and ranging lines, the crew could keep the Command Module within an acceptable envelope while manually guiding the Command Module to a suitable landing site.
  
  The EMS was installed in the Command Module for all of the manned Apollo missions and occupied prime space in front of the Commander.  It could have saved the lived of the crew if the single computer would have failed.  The EMS can be seen in the cockpit display of the Command Module on exhibit at the Smithsonian Institute.

• Space Shuttle-Orbiter Design for Multiple Atmospheric Entry Reuses:  The requirement to design the Orbiter for multiple atmospheric entry flights imposed a raft of difficult subsystem design requirements and a gigantic integration problem.  The desires or needs of one subsystem almost always conflicted with another subsystem.  For example, the aerodynamic heating people and the people responsible for finding temperature resistive materials preferred a trajectory that flew high in the atmosphere because the external surface temperatures would be lower.  In contrast, the thermal people and the structural design people preferred a trajectory that flew low in the atmosphere because the back face temperature; that is, the temperatures on the inside of the Orbiter, would be lower.  In addition, there were finite limits as to how high or how low the Orbiter could actually fly because of the dynamics of atmospheric entry.  And there were very real limits on the maximum temperatures that the TPS material could withstand.   And There was a TPS weight limitation as well.  This tip-of-the-iceberg introduction gives an idea of the complexities involved.
  
  Elvin Knotts' role, with the engineers that reported to him was to work as a trajectory and guidance specialist.  As a team member, he worked with all of the necessary discipline specialists from Rockwell International as well as the NASA and other contractors to find a way to make it work.  It was a lengthy process that involved complex calculation techniques, rigorous searching for acceptable solutions, and a great deal of integration.
  
  All of the effort paid off.  Every so often the Orbiter safely returns to the Earth following that tight-rope through the atmosphere. 

Apollo/Moon Pictures
	Apollo Launch		Apollo Launch
	Mr. Armstrong, Mr. Alden and Mr. Collins.		The earth as seen from the moon.

Space Shuttle Pictures

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Elvin Knotts can be contacted at knottsep@earthlink.com . 

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