THE "WHERE" AND "WHEN" OF EACH APOLLO
LANDING WAS CAREFULLY PLANNED

( Coincidences Don't Happen )

By Marvin Czarnik
Retired Aerospace Engineer

Mr. Czarnik was an employee of McDonnell Douglas for over 35 years, and worked with NASA on guidance and mission planning for most of the manned spacecraft programs, Mercury, Gemini, Apollo, Skylab and Shuttle. He worked with NASA's Mission Planning and Analysis Division and participated in astronaut training for most missions. He was a recipient of the Manned Spacecraft Center's Achievement Award for the Gemini Rendezvous Operations Planning Team, which planned the first successful rendezvous in space. He worked closely with Buzz Aldrin in developing rendezvous plans and procedures, even before Buzz became an astronaut. Mr. Czarnik is a former Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA) and is a current Member of the National Space Society (NSS).

BACKGROUND

Mission planning has been a vital part of our space program since its very beginning. For the manned spacecraft program, mission planning started fairly simple with Project Mercury and then got progressively more complicated with Project Gemini and Project Apollo. NASA recognized early the importance of mission planning by establishing a Mission Planning and Analysis Division within the Flight Directorate at the Manned Spaceflight Center ( renamed later as the Johnson Spaceflight Center) in Houston. Mission Planning's job basically was to determine the trajectories, orbits and maneuvers required to achieve mission success, while maintaining acceptable safety margins.

MERCURY   For Mercury the missions were fairly simple, i.e., launch due East into a low earth orbit, orbit for a day or two and then re-enter and splash down in the ocean near the recovery ships. The usual range safety constraints applied to the launch and in addition launch and splash down were to occur in daylight.

Apollo required the most complicated mission planning of all the manned spacecraft missions. Launching a spacecraft to the moon, maneuvering to place and keep it on a satisfactory trajectory to the moon, maneuvering to put it into an orbit that will pass over the desired landing site, maneuvering to place the Lunar Excursion Module (LEM) on a satisfactory decent trajectory toward the surface of the Moon, and finally maneuvering and decelerating (braking) the LEM to gently touch down at a preplanned location on the Moon, at a preplanned time of arrival, requires precise mission planning. The key decisions that drives the mission plan is, where (latitude and longitude) do you want to land on the Moon, and when, i.e., date and time ( hour, minute and second) do you want to arrive there. The launch time, the earth orbit into which the spacecraft is inserted, the time and magnitude of the Trans-Lunar Injection (TLI) maneuver that will place the spacecraft on a trajectory that will take the spacecraft around the moon, the time and magnitude of the maneuver that places the spacecraft into the proper orbit around the moon, the time and magnitude of the decent maneuver of the LEM, and the LEM braking and steering maneuvers, all are determined based on the location and time for the desired landing on the moon. When one considers the fact that the Earth is rotating, the moon is rotating, and both are orbiting about the sun, that the axis of rotation of the moon is at a different angle than that of the earth, that the moon's axis of rotation and its orbit around the Earth precess ( wobble), and that the force of gravity for the moon is significantly different than that of Earth, the complexity of the mission planning required to successfully land at the desired spot on the moon at the desired time, becomes apparent.

If the performance of the spacecraft and crew is as expected (nominal), the mission events and trajectories will be as planned (nominal) and the spacecraft will land on the moon according to the plan (time and place). . In short, when the spacecraft and crew perform normally, things happen according to the mission plan, i.e., there are no surprises or unexpected results. The spacecraft trajectory is constantly monitored, and deviations are detected and correction maneuvers are made to drive the trajectory back to nominal.

APOLLO 11

For the specific case of Apollo 11, there were only minor deviations from the nominal preplanned trajectories, and Apollo 11 landed where and when it was supposed to land, according to the mission plan established, published and rehearsed long before the actual mission took place. The conditions at the landing site, such as the general terrain, the view through the spacecraft windows, the sun lighting conditions (contrast and shadowing of the lunar surface), and the star-field over the horizon were as planned. No geographic or astronomical situation that existed at the landing site occurred by chance or coincidence, it was all according to plan. It is important to note that while it is true that the visible star field had a function in supporting some parts of the mission, such as midcourse guidance and rendezvous back-up guidance, the visible star field at the landing site had no useful function or use in supporting the mission. So, what was the significance of the visible star field at the landing site?

The required conditions at the planned lunar landing site include:

1. A fairly level touch down point, so the LEM will not tumble or fall over and will be nearly erect for the lift off back to lunar orbit, 2. identifiable land marks, so that the crew can determine where it is, particularly in the case where the descent trajectory is significantly off nominal, 3. a soft landing, including minimum or no down range or cross range velocity at the time of impact, so that no damage is done to the spacecraft and its equipment, 4. Sufficient consumables to sustain the crew while inside the LEM, on the surface of the moon, 5. a sun angle at the landing site that will provide adequate light and contrast to support a successful landing, especially to support a manually controlled landing, as was the case for Apollo 11, and of course, 6. an operational launch system for lifting off into lunar orbit when it is time to leave the lunar surface. The view of the sky above the lunar horizon, including the stars, is not used for terminal landing control or for the launch phase off the moon, not even for back-up guidance and control. This would lead one to believe that the visible star field at the landing site at the time of landing or any time while they were on the surface of the moon was no import as far as the operational mission was concerned. So then, why does a particular star pattern repeat at several of the Apollo landing sites, at the time of landing and/or liftoff, as reported recently by Richard Hoagland? Why does this same enigmatic pattern occur in other NASA missions? Should we believe it is all just coincidence that has produced such results for such complicated, precisely planned missions? Or is there another explanation?

REFERENCES:

Aldrin, Edwin E., Jr. " Line of Sight Guidance Techniques for Men in Orbital Rendezvous", Ph.D. dissertation, Massachusetts Institute of Technology, 1964

Adrin, Buzz and Malcolm McConnell, "Men From Earth", 2nd Edition, New York: Bantam Falcon Books, 1991

Armstrong, Neal, Michael Collins, and Edwin E. Aldrin, Jr. "First On the Moon", Boston: Little, Brown and Company, 1970

Chaikin, Andrew. "A Man On The Moon", New York: Penguin Books, 1995

Chappell, Russell E. "Apollo", NASA Washington D.C.: Government Printing Office, 1972

Collins, Michael, "Carrying The fire: An Astronaut's Journeys". New York: Farrar, Strauss and Giroux, 1974

Compton, William David, "Where No Man Has Gone Before: A History of the Apollo Lunar Exploration Missions", NASA SP 4214: Washington D.C.: Government Printing Office,1989

Czarnik, Marvin R. and Peggy Dugge, "Practice Rendezvous Mission", McDonnell Guidance and Control Design Note No. 1, July 1962

Czarnik, Marvin R. and Richard Hamm, "Description of the Gemini VII Station Keeping Simulation", McDonnell Gemini Guidance and Control Design Note No. 388, 13 July 1996

Evans, Barnaby and Marvin Czarnik, "Summary of Rendezvous Operations: Gemini Technical Summary", NASA, MSC G-R-66-5, Houston, July 1966

NASA Manned Spacecraft Center, "Apollo 11 Preliminary Science Report", NASA SP 214. Washington, D.C.: Government Printing Office, 1969

NASA, "On The Shoulders Of Titans: A History of Project Gemini", NASA SP- 4203, Washington D.C.: Government Printing Office,1977

NASA,"The Apollo Spacecraft: A Chronology Vols. 1-4". Washington D.C.: Government Printing Office, 1969-78

Thomas, Wayne, "Story of Expert Who Made Space Linkup Feat Possible", Chicago Tribune Article (Front Page): Chicago, Sunday December 26, 1965.

Wilhelms, Don E. "To A Rocky Moon: A Geologist's History of Lunar Exploration". Tucson and London The University of Arizona Press, 1993