Future Human Exploration Challenges: An Overview

Definition

Human Space Exploration beyond low Earth orbit could include a return to the moon, exploration of Mars, and stay in cis-lunar space and at Lagrangian points, as well as exploration of asteroids.

Introduction

Humans have been flying into space and back for well over 50 years. Crews are now routinely sent to the International Space Station (ISS) for durations of approximately 6 months, and in one case (as of 2019), two people have lived and worked on board for almost a year (340 days). A substantial body of work now exists on the human health and performance effects of these flights in low Earth orbit (LEO). Although challenges remain, the major risks to humans from flights of this duration and distance have likely been identified, and countermeasures and technologies are in place or under study to minimize these risks. A significantly smaller number of people have flown to the moon, and only 12 astronauts have walked on the lunar surface. Although those flights involved...

Glossary

Analog facility

A ground-based facility that mimics some aspects of space flight (e.g., isolation, confinement, physiological deconditioning) and allows for scientific investigations to occur in a controlled and less-expensive setting

Cis-lunar

The three dimensional region of space between the Earth and its moon

Complex system

A system made up of many smaller interacting subsystems, leading to emergent behaviors that cannot be predicted based on the properties of the individual subsystems; the interactions provide the dominant dynamics

EVA

Extra-vehicular activity – operations conducted in space by a suited astronaut outside of the spacecraft, including those conducted on the surface of another celestial body

Exploration space flight

Human space flights beyond low Earth orbit, with the intent of exploring other celestial bodies or locations

HSI

Human-systems interaction, an engineering approach in which the combined properties of humans and the (mechanical, electrical, computing) systems that they interact with are specifically recognized and addressed

ISS

International Space Station

Lagrange or Lagrangian point

A point in space where the gravitational attractions of two large bodies provide the centripetal force for a third smaller object, allowing it to orbit with them without expending significant energy.

LEO

Low Earth orbit – an orbit of Earth with an altitude between 160 and 2000 km

NEO

Near-Earth object – a comet, asteroid, or meteor that is “near” Earth or its orbit (within 45 million km)

Trans-lunar

The three-dimensional region of space beyond Earth’s moon and its orbit