New simulation of the Apollo 13 explosion. Photo: Analytical Graphics, Inc.

Thirty years ago this week, Apollo 13 ground and flight crews overcame substantial obstacles following an on-board explosion to return three stranded astronauts safely back to Earth. Analytical Graphics, Inc. (AGI) has announced interesting results that change what history books have written as the predicted outcome of this adversity had NASA not been able to successfully rescue Apollo 13.

In most historical accounts of this event, records indicate that if Apollo 13 was unable to perform any maneuvers following the explosion, the crippled spacecraft would have never returned to Earth, missing it by over 40,000 miles and becoming a piece of eternal space debris. AGI begs to differ.

In preparation for the 30th Anniversary of this historic event, AGI and business partner Space Exploration Engineering (SEE) recreated actual Apollo 13 mission trajectories, including the maneuvers executed to return the crew to Earth, using AGI's Satellite Tool Kit (STK) with STK/Astrogator. The team also analyzed the "what if" scenario to determine the mission's outcome if the spacecraft's orbit could not have been altered following the explosion. STK analysis revealed that the often-published 40,000-mile figure is extremely inaccurate. Results reveal that the Apollo 13 spacecraft would have come within a mere 2,300 nautical miles of the Earth and swung back out into a new fatal orbit, only to re-enter the Earth's atmosphere on May 20, 1970 and burn up in a steep re-entry over the eastern Atlantic Ocean.

Mission Commander Jim Lovell reportedly stated at the time he would have rather burned up in the Earth's atmosphere than become a permanent orbiting monument to America's space program. As a result of AGI's and SEE's efforts, analysis shows that had the crew not returned safely to our home planet, Lovell would have had his final wish granted. For more information on the revolutionary STK analysis of the Apollo 13 mission, including orbital diagrams and 3D animations of key mission sequences, visit their Web site.

Space Exploration Engineering is an AGI Business Partner that offers customers custom space systems solutions, specializing in interplanetary and earth-orbiting mission analysis, spacecraft operations, spacecraft systems engineering, and aerospace video services.

Analytical Graphics, Inc. provides commercial off-the-shelf (COTS) analysis and visualization software solutions to over 23,000 aerospace industry professionals through its core product Satellite Tool Kit (STK) and a series of specialized STK add-on modules. STK supports end-to-end aerospace systems from mission planning through operations and is available free of charge to all aerospace professionals.

Basic applications include calculating and visualizing a vehicle's position and attitude, determining acquisition times, and analyzing the vehicle's field of view. The core functions of STK can be extended with a wide range of add-on modules from AGI that address specialized analysis needs, such as detailed communication link analysis, collision analysis, coverage analysis, maneuver planning, orbit determination, and real-time visualization.