A Giant Leap For Science
“That’s one Step for a man; one giant leap for Mankind”
—Astronaut Neil Armstrong as he stepped onto the lunar surface, July 20, 1969
In 1961, when John F. Kennedy proposed “landing a man on the moon and returning him safely to Earth” by the end of the decade, he inspired a generation of Americans to achieve technological advances that continue to fuel our progress in avionics and space exploration. Among the talented Apollo scientists, engineers and technicians who demonstrated a remarkable capacity for problem solving was James Hand ’60, a physicist who, as a member of the MIT Instrumentation Lab headed by Charles Stark Draper, helped develop the guidance, navigation and control systems that helped Neil Armstrong, Edwin “Buzz” Aldrin and Michael Collins accomplish man’s first lunar landing and safe return.
The challenge, Hand explained to an audience at Washington College in March 2012, was to guide a spacecraft on a round trip of more than half a million miles, and to achieve a controlled, precise landing on the lunar surface on the very first try. There was not enough fuel available for a second attempt. The lives of the astronauts—and a multi-billion dollar investment in space science—were at stake.
As the Lunar Module approached the chosen landing area, Sea of Tranquility, Hand recounted that fuel levels ran critically low. Should the two astronauts land short, dropping into a lunar crater, or fly over it, given the chance of running out of fuel and crashing? Meanwhile, astronaut Michael Collins orbited overhead in the Command/Service Module. The steely-nerved astronauts opted to fly over the crater and settled the Lunar Module onto a relatively smooth surface with just 22 seconds of fuel remaining. They had set their course by the stars and achieved the safe landing through a series of careful calculations, bold decisions and good old-fashioned American ingenuity.
“The Apollo program was America’s greatest technological achievement,” Hand recalls. “The thinking was and remains: if we can land on the Moon, anything is possible.”
“Man’s rush into spaceflight during the 1960s demanded fertile imagination, bold pragmatism, and creative extensions of existing technologies in a myriad of fields,” Charles Stark Draper recounted in 1971. “The achievements in guidance and control for space navigation, however, are second to none for their critical importance in the success of this nation’s manned lunar-landing program, for while powerful space vehicles and rockets provide the environment and thrust necessary for space flight, they are intrinsically incapable of controlling or guiding themselves on a mission as complicated and sophisticated as Apollo. The great achievement of the MIT Laboratory was to supply the design for the primary hardware and software necessary to solve the Apollo guidance, navigation and control problem. It is to the credit of the entire team that this hardware and software have performed so dependably throughout the Apollo program.”
Hand received a special commendation for his role in the design and development of the Alignment Optical Telescope for the Lunar Module Primary Guidance Navigation and Control System. The periscopic sextant device, mounted on the navigation base and operated manually by the astronauts, was used for guidance system alignment to the stars during operations on the lunar surface. Hand also worked on integration of the Guidance, Navigation and Control System in the Command Module, by which the vehicle could achieve the required functions to safely complete the whole mission without support from Earth-based stations, if need be. By conducting many self-contained star/landmark sighting practices, the astronauts proved that their guidance, navigation and control solutions compared favorably with the solutions communicated from the ground-based stations.
“To get to the moon we had a preselected catalogue of only 23 stars, knowledge of the stellar constellations and roughly a hundred known landmarks,” remarked Hand. Typical in-flight sightings included two stars at a time for guidance system alignments. Two or three stars and a landmark were used for the spacecraft position measurements.
Every detail in anticipation of Apollo 11’s lunar landing was carefully tested and evaluated. Hand recounted his test support at Kitt Peak National Observatory in Tucson, AZ, where stars could not be sighted through the Alignment Optical Telescope due to scattered sunlight simulated by a searchlight. “We realized there would be occasions on the lunar surface when the astronauts couldn’t see the stars because of scattered light from the sun,” Hand recalled. “I had a conical sunshade we used in the lab and it worked like a charm. Back at Draper Lab, I reported that we would have to change the design of the telescope to incorporate a sunshade. It ended up costing an additional half-million dollars to add the sunshade, thereby allowing proper function of the $14 million telescopes for the Apollo program.”
Hand supported preflight testing for Apollo 11 at Cape Canaveral. One memorable effort was climbing inside the Saturn V rocket in order to develop a verification test of guidance system change-out, if needed. Fortunately, the difficult test was never needed throughout the duration of the Apollo program.
He remembers Doc Draper, the brilliant scientist known as the father of inertial navigation, as a kind man who generously acknowledged the contributions of his young engineer during support of Apollo 11 at the Mission Control Center in Houston, TX. “After the successful return to Earth, here I was, 32 years old, and Doc loaned me his badge to get into the VIP room where all the captains of industry and astronauts were gathered. It was exciting to meet many of these leaders and to think that, in a way, we went up on the moon, too. We did, in fact— before the launch, we had all signed documents that went along onto the Moon. Of course, those leaders realized when they looked at the badge on my chest that they knew Doc Draper, and I was no Doc Draper,” quipped Hand.
Hand supported several other moon flights, including Apollo 13. His later work also helped refine the steering systems for the Space Shuttle as well as the MX, Minuteman and Trident strategic missiles, which played a role in ending the Cold War. These efforts also resulted in guidance, navigation and technologies for protecting the Earth against threatening asteroids.
“I share the opinion of many scientists that the issue is not whether a large asteroid—larger than about 0.5 km across—will strike the Earth, but when it will happen,” Hand says. Presently, there are automatic telescopes with cameras that search the heavens from the North and South hemispheres to detect large asteroids that may threaten the Earth.”
Hand notes that scientists will need ample warning of an impending asteroid collision, years in fact. Scientists are now studying the physics of asteroids and considering methods to push or pull a body away from an orbit of collision. One idea, proposed by former astronaut Russell Schweikert, is to attach a rocket to an asteroid and push it in the desired direction. Another method under consideration is to rendezvous and land a solar sail on an asteroid and use the solar wind (protons and other particles) to gradually move the asteroid away from impending collision with Earth. This method has been successfully tested in space flight.
Sound far-fetched? Hardly, Hand notes, thanks to the efforts of engineers who, four decades ago, figured out how to safely escape Earth’s orbit and navigate deep space. It was, as Neil Armstrong famously put it, “… a giant leap for Mankind,” paving the way for pioneering missions that the Apollo astronauts could scarcely imagine.
The legacies of Apollo are manifold, yielding many times the monies expended according to NASA. One Apollo experiment is being operated to this day and is especially important. Earth-based telescopes send laser beams toward the Moon. Laser retro-reflectors left there by the Apollo missions return the signals and the Earth-Moon distance is measured. Early measurements to present measurements indicate that the Moon is retreating from Earth in the range of 22 to 38 mm per year. While small, it is important to assure that these values do not accelerate significantly over the long term as ocean tides and seasons would be adversely affected.