@misc{indiciaeee516ed71845,
  title = {Exploration Technology Program plans and directions},
  author = {Aldrich, Arnold and Rosen, Robert and Craig, Mark and Mankins, John C.},
  year = {1990},
  url = {https://ntrs.nasa.gov/citations/19910029130},
  note = {Source identifier: 19910029130}
}