Monday, 11 April 2016

Morris Jenkins Helped Guide Astronauts to the Moon and Back

Photo: Morris Jenkins (right) receives NASA Superior Achievement Award in 1969. NASA Photo

When NASA chose to send its Apollo astronauts to the moon using the method known as Lunar Orbit Rendezvous, it avoided the challenge of building a monster rocket far bigger than the Saturn V that would have been necessary for a direct flight to the moon and back. But it complicated the route each flight would have to take. Among other things, the astronauts would have to rendezvous and dock two spacecraft in lunar orbit to get home.

To make Apollo a success, NASA called on engineers and scientists to plot the complicated trajectories astronauts would need to follow for their lunar flights. One of those experts was a modest British engineer who was a member of the group of 32 British and Canadian engineers who got work at NASA after the Canadian government cancelled the CF-105 Avro Arrow supersonic interceptor in 1959.

That engineer, Morris Jenkins, has died at age 92.

The highlight of Jenkins’ 25 years at NASA was leading a group in the Mission Analysis and Planning Group (MPAD) at the Manned Spacecraft Center (since 1973, the Johnson Space Center) at Houston, Texas, that developed lunar trajectories for Apollo spacecraft.

In describing the trajectories in a talk at the Apollo Lunar Landing Mission Symposium in Houston in June 1966, Jenkins spoke of the complexities of Apollo’s flights, which started off with putting a spacecraft into an orbit around the Earth that was tilted in relation to both the Earth’s equator and the Moon’s orbit. 

At the right moment, the spacecraft had to be injected into a path that just missed, by slightly more than 100 km, where the Moon would be when the spacecraft arrived in three days time. The spacecraft’s return path to Earth had to place it into a very narrow corridor that ensured that the spacecraft hit the Earth’s atmosphere at the right place and at the right angle. A tiny error meant that the crew would be lost. Crews that landed on the Moon faced additional complexities. And it also had to be taken into account that the Earth and Moon orbit the Sun, are not perfect spheres and wobble slightly in their orbits.

Starting not long after President John F. Kennedy and Congress charged NASA with flying astronauts to the moon, Jenkins and his group at MPAD used a complicated mathematical estimation method, some outside help, and brute computing power to prepare trajectories for lunar missions and give the people planning Apollo confidence that Apollo could be safely guided to their targets and back home. Based on this work, another group drew up the detailed trajectory calculations for each mission.

Morris Vivian Jenkins was born in Southampton, England, on May 3, 1923, and served in the Royal Air Force during the Second World War as a navigator. While in the RAF, he came to Rivers, Manitoba, for training under the Commonwealth Air Training Plan. 

After the war, he worked at the Supermarine technical office of Vickers Armstrong for nine years, during which he learned stress, aerodynamics, and stability and control. Jenkins earned a degree in Mechanical Engineering in 1951. He moved to Canada and joined Avro Canada at its plant at Malton, Ontario, in 1956. There he worked on stability and control aspects of the Avro Arrow until its cancellation. Once he was hired by NASA in 1959, Jenkins worked on control systems in Mercury before moving into his work on lunar trajectories for Apollo in 1961.

Jenkins was always modest about his work, and required a great deal of persuasion before agreeing to talk to me when I came to interview him for the book I wrote on the Avro-NASA engineers. “It wasn’t easy to get this trajectory scheme going. The group that I led did it. It wasn’t I who did it,” he explained.

By the time of Apollo 11, Jenkins was working for fellow former Avro Canada engineers John Hodge and Dennis Fielder on future programs, when Manned Spacecraft Center director Bob Gilruth asked Jenkins to draw a up a plan for a trip to Mars. Jenkins was able to call on help from many of his colleagues from NASA and from the aerospace contractor TRW. “Even with a realistic perspective on the whole thing, we put out an energetic effort on it. It was a good first draft and sent to headquarters,” he said.

The Jenkins report, as it was known, was completed in February 1971 and called for an “austere” low-budget program sending an initial expedition of 570 days to Mars in 1987 and 1988. Jenkins’ plan assumed that NASA had already developed a shuttle and that components of the solar-powered Mars vehicle would be assembled in Earth orbit following seven launches using shuttle booster vehicles.

After 15 days in orbit around Mars, three of the five astronauts on the trip would descend to the surface in a Mars exploration module for 45 days of exploration. On its way back to Earth, the spacecraft would swing by Venus and enter Earth orbit for a pickup by shuttle at the end of its trip. Unfortunately, NASA was not able to act on Jenkins’ proposals.

Jenkins worked briefly on Skylab and then in the Space Shuttle program as Chief of the Powered Flight Analysis Branch, which prepared launch trajectories, until he retired from NASA in 1984.

After a long retirement with his wife Joan, who had also worked in the space program, Jenkins passed away in Dallas on March 15, 2016.

No comments:

Post a Comment