[ COSMOS ]
Distance & Time
Light speed is the upper bound for information and causality; spacetime and gravity set the scale of the universe. To explore, communicate, and cooperate across greater distances, we must find new theoretical and technical paths within physical law. The following directions have both fundamental and human relevance.
Time dilation, gravitational redshift, and curvature have moved from theory to engineering: GPS and future deep-space navigation must account for relativistic effects. Precise measurement and use of these effects improve navigation and communication and deepen our understanding of spacetime, laying groundwork for deep-space and interstellar missions.
Entanglement cannot send information faster than light, but quantum key distribution and repeaters can build theoretically unhackable secure links. From ground to satellite and city to deep space, quantum communication has important applications in defense, finance, and future interstellar missions, and advances our understanding of nonlocality.
In deep-space or interstellar scenarios, latency is measured in minutes or years. How to design delay-tolerant consensus, coordination, and autonomous decision systems? This is both an engineering need for exploration and drives new understanding of causal order and distributed consistency in a relativistic setting, with implications for delay-sensitive systems on Earth.
Longer journeys need more efficient propulsion and energy: electric and nuclear propulsion, light sails, and novel concepts are being explored. Life support, radiation protection, and closed ecology for sustained human presence on the Moon, Mars, and beyond sit at the intersection of aerospace, physics, and biology—and the possibility of a multi-planet species.
Relativity requires that cause, effect, and information do not exceed light speed; entanglement exhibits nonlocal correlation but cannot be used for superluminal classical communication. At interstellar distances we must design communication, navigation, and coordination under “delay is inevitable”—a fundamental challenge for engineering and algorithms.
“Simultaneity” is frame-dependent in relativity; clocks in high speed or strong gravity do not match Earth’s. Defining “global time” or “consistent state” across frames requires strict relativistic treatment. Deep-space missions, future interstellar networks, and science depend on progress here.
Chemical propulsion has limited specific impulse; fusion, antimatter, and other concepts offer higher efficiency in theory but controllable, safe, engineerable systems remain extremely difficult. Reaching deep space requires systematic advances in materials, physics, and engineering.
Radiation, microgravity, closed environment, and resource cycling pose serious challenges to crew health and sustained presence. Reliable life support and ecological recycling within mass and power limits are scientific and engineering must-haves for human deep-space exploration and off-world settlement, and advance our understanding of life’s limits and Earth’s biosphere.
Electric and nuclear-thermal/electric propulsion, light sails and advanced concepts; propellant and power systems. More efficient, reliable propulsion is key to deep-space and crewed Mars missions and a high-value area at the intersection of physics and engineering.
Gravitational-wave detection, precision timing and relativistic navigation, curvature and cosmology. From theory to navigation and communication, relativity is deeply embedded in modern technology; understanding spacetime helps humanity move into deep space more robustly.
Quantum key distribution, repeaters, and satellite quantum communication; long-distance secure and deep-space links. Quantum technology offers new possibilities for security and future interstellar communication, with both scientific and strategic value.
Space physiology and radiation, closed ecology and life support, in-situ resource use. Enabling humans to live and work healthily and sustainably on the Moon, Mars, and beyond is a long-term goal for human spaceflight and a shared human future, requiring deep integration of biology, engineering, and medicine.
Developing high-specific-impulse, long-life propulsion and energy systems suited to deep space to shorten flight times and reduce risk and cost for Mars and beyond, and to lay the foundation for crewed deep-space exploration and future interstellar travel.
Designing protocols and autonomous decision systems that remain reliable under minute- to year-scale latency for deep-space craft and future lunar and Mars bases, and advancing delay-tolerant and distributed-systems theory.
Establishing a unified spacetime reference and high-precision navigation that account for relativity, serving deep-space missions, satellite constellations, and science while deepening our understanding of gravity, spacetime, and cosmic structure.
Overcoming radiation, microgravity physiology, closed ecology, and resource cycling so humans can live and work healthily on the Moon and Mars long-term. This is essential for mission success and expands our understanding of life’s limits and sustainable existence, with implications for Earth’s ecology and humanity’s future.