Skip to main content

Human Exploration of Space A Review of NASA's 90-Day Study and Alternatives (1990) / Chapter Skim
Currently Skimming:

I. Alternative Mission Concepts
Pages 5-10

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 5...
... Although it is technically feasible to go to the Moon and Mars without the intermediate step of establishing a permanent station in low Earth orbit (LEO) , most of the mission architectures under consideration employ a station for assembly of vehicles for travel beyond Earth, for storing fuel and supplies, and as a human transfer facility.
Read the entire page →
From page 6...
... THE NASA REPORT OF THE 90-DAY STUDY ON HUMAN EXPLORATION OF THE MOON AND MARS The NASA Report of the 90-Day Study provided descriptions of five reference approaches: Approach A is formulated to establish human presence on the Moon in 2001, and the Moon is used as a learning center to develop the capability to move on to Mars. An initial nuclear power unit and lunar oxygen production demonstration hardware are added in 2003 to reduce lunar logistics requirements.
Read the entire page →
From page 7...
... They employ unmanned robotic precursor missions, reusable transfer vehicles to lunar and Martian orbits, and excursion vehicles at surface bases. Each features sequential Moon and Mars programs, assumes zero gravity in transit to Mars and requires a decade or more of research on adaptability of humans to low or zero gravity, depends on aerobraking (using atmospheric drag to slow a vehicle for capture in the planetary gravity field)
Read the entire page →
From page 8...
... Human experience in space suggests that less EVA means safer missions, owing to the limited maneuverability and flexibility of astronauts in currently available space suits. Emphasis on teleoperations or more synergistic human/machine interactions can provide substitutes for extensive EVA But to facilitate a wide range of human activities in space, it seems desirable to develop an improved space suit for necessary EVA tasks.
Read the entire page →
From page 9...
... Further, The Great Exploration proposes no robotic precursor missions to learn more about the environments of the Moon or Mars or to identity safe or scientifically interesting landing sites. The committee believes The Great Exploration underestimates the many engineering and operational challenges involved in bringing its technical concepts to practical realization.
Read the entire page →
From page 10...
... Among other early architectures that might be considered are the NASA baseline concept, with the initial Mars base in orbit rather than on the surface and the NASA baseline with separate cargo and crew transport systems, the latter with high-speed, staged chemical propulsion and even Earth launch of lunar and Mars missions. The committee is convinced that other alternatives will arise as concept development proceeds.
Read the entire page →

Key Terms

  • heavy lift
  • human exploration
  • reference approaches
  • zero gravity
  • lift launch

  • launch vehicle
  • essentially identical
  • chemical propulsion
  • nasa report
  • await technology

  • mars orbit
  • nasa baseline
  • robotic precursor
  • mission configurations
  • martian atmosphere

  • space exploration
  • precursor missions
  • lunar oxygen
  • human space
  • nuclear propulsion

  • core modules
  • engines using
  • reusable transfer
  • planetary gravity
  • assumes zero

  • inflatable structures
  • estimated low
  • lift vehicles
  • production demonstration
  • challenges involved


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.