d stuff to get the crew back,” says Deiterich, who worked for NASA for 30 years. “I’d say 80 to 90 percent of our work [at NASA] was figuring out how to do things if they weren’t nominal.” Training simulations are one thing, but in the nine years of the Apollo program, this was the first time that a retro team had to execute a real-world abort scenario. History Shorts: How Apollo 13 Found Its Way Home Stranded in space, the Apollo 13 astronauts managed to find their way back home by using technology invented centuries earlier. 1:03m watch What Is a Free-Return Trajectory? The first option if something went wrong on an Apollo mission was a so-called “direct abort.” For that emergency maneuver, the astronauts would spin the command service module 180 degrees so that its tail was pointing forward. Then they would blast the spacecraft’s engines at full power, rapidly decelerating from 25,000 mph to a standstill before rocketing in the opposite direction. With the command and service module’s engines down, however, Deiterich and his team dismissed the direct abort option. The next-best plan was to catch a “free ride” home using the moon’s gravity as a slingshot. Starting with Apollo 8—the first manned space flight to orbit the moon—every Apollo crew had followed the free-return trajectory on its way to the moon. If something went wrong with the spacecraft’s engines, the free-return trajectory would whip them around the back of the moon and send them on a safe path back to Earth. Apollo 13 was the first crewed mission to experience a catastrophic spacecraft failure. Not only was Apollo 13 the first time that a free-return trajectory was used in an abort scenario, but unlike those earlier Apollo missions, Apollo 13 wasn’t on a free-return trajectory when the explosion happened. Instead, the spacecraft was on a “hybrid” trajectory that positioned the astronauts to land on the moon’s Fra Mauro Highlands. If the astronauts stayed on that hybrid trajectory, they would still sl

# Who developed the mathematics used to correct the trajectory of Apollo 13? Tags: apollo-program, mathematics, guidance, apollo-13 - Score: 21 - Views: 4569 - Answers: 1 - Answered: yes - Asked by: DrSheldon (49636 rep) - Asked: 2020-04-15 - Edited: 2020-04-16 - Site: space ## Question The 1967 NASA technical note D-4246, Midcourse Guidance Procedure with Single Position Fix Obtained From Onboard Optical Measurements describes correcting the trajectory of a spacecraft traveling between the moon and Earth, using an on-board telescope to point at stars or other fixed objects in space. This method was later used to correct the flight of Apollo 13. Who were the authors of this paper? Did they include anyone notable? This question is part of a series honoring the 50th anniversary of Apollo 13, "NASA's finest hour". ## Answers ### Answer by Ludo (score: 34 [ACCEPTED]) The authors of the paper are Harold A. Hamer, Katherine G. Johnson, and W. Thomas Blackshear. Of these, the name Katherine Johnson might ring a bell with people, as she was one of the protagonists in the 2016 movie Hidden Figures, honouring the women that were instrumental in the early days of the US space program

Apollo 13 Guidance, Navigation, and Control Challenges - NASA Technical Reports Server (NTRS) ## NTRS ## NTRS - NASA Technical Reports Server Search Collections About News Help Login Back to Results Apollo 13 Guidance, Navigation, and Control ChallengesCombustion and rupture of a liquid oxygen tank during the Apollo 13 mission provides lessons and insights for future spacecraft designers and operations personnel who may never, during their careers, have participated in saving a vehicle and crew during a spacecraft emergency. Guidance, Navigation, and Control (GNC) challenges were the reestablishment of attitude control after the oxygen tank incident, re-establishment of a free return trajectory, resolution of a ground tracking conflict between the LM and the Saturn V S-IVB stage, Inertial Measurement Unit (IMU) alignments, maneuvering to burn attitudes, attitude control during burns, and performing manual GNC tasks with most vehicle systems powered down. Debris illuminated by the Sun and gaseous venting from the Service Module (SM) complicated crew attempts to identify stars and prevented execution of nominal IMU alignment procedures. Sightings on the Sun, Moon, and Earth wer

stem and a thorough review by NASA of all Apollo systems that use cryogenic oxygen. The Review Board also recommended that management and organizational structures be strengthened to ensure an adequate understanding of the engineering and manufacturing processes of subsystems. For Apollo 14 and future missions, engineers at NASA and North American Rockwell redesigned the oxygen tank system by adding a third tank in a different bay, upgrading thermostats, removing stirring fans and sheathing all electrical wiring in stainless steel. Lessons Learned Resources NASA Report Apollo 13 Mission Review Hearing Before the Committee on Aeronautical and Space Sciences Read Report NASA Report Apollo 13: The Successful Failure Read Report NASA Podcast Houston We Have a Podcast: Apollo 13 Listen to Podcast NASA Video Apollo 13: Home Safe Watch Video NASA Video Apollo 13: 'Houston, We've Had a Problem' Watch Video NASA Video Apollo 13 Views of the Moon in 4K Watch Video Smithsonian Video How Mission control Saved the Apollo 13 Crew Watch Video The Infographics Show Video Apollo 13 Space Mission Disaster (Hour by Hour) Watch Video NASA Course Apollo 13 Case Study Start Course The Infographics Show Video Apollo 13 Space Mission Disaster (Hour by Hour) Watch Video Apollo 13 Tributes There are a number of tributes throughout the United States dedicated to Apollo 13 and her crew. Apollo 13 Bronze Statue Space Center Houston 1601 E NASA Parkway Houston, TX 77058 Learn More about the Apollo 13 Bronze Statue Fred Haise Statue Biloxi, MS Learn More about Fred Haise Statue Jack Swigert Statue United States Capital Visitor Center's Emancipation Hall, First St. SE Washington DC, 20515 Learn More about Jack Swigert Statue Jim Lovell Statue Adler Planetarium and Astronomy Museum, 1300 S DuSable Lake Shore Dr. Chicago, IL, 60605 Learn More about Jim Lovell Statue Apollo 13 Multimedia and Resources Apollo 13 Apollo 13: Mission Details 50 Years Ago: Apollo 13 Preps for 3rd Moon Landing 50 Years Ago