If you have ever wondered whether space and outer space are the same thing, or where one ends and the other begins, you are not alone. These terms get used interchangeably all the time but they carry slightly different meanings depending on context. More importantly, understanding what space and outer space actually are helps you make sense of what commercial spaceflight companies are offering and what it means to actually leave Earth's atmosphere. This blog breaks down the science, the definitions, and the practical reality of what exists beyond our planet, all of it relevant for any American traveler thinking about making the trip.
The terms space and outer space are related but not always identical in technical usage. In everyday language, both refer to the region beyond Earth's atmosphere. In scientific and regulatory contexts, space typically refers to everything above the Karman line, which is set at 100 kilometers above Earth's surface. This is the internationally recognized boundary used by organizations like the Federation Aeronautique Internationale and referenced by Blue Origin for its New Shepard missions. Outer space in scientific literature often refers more broadly to the expanse beyond any planetary atmosphere, encompassing the interplanetary medium, the regions between star systems, and beyond. For practical purposes in commercial spaceflight, space and outer space refer to the environment above 100 kilometers where there is no significant atmospheric density, no breathable air, no weather in the traditional sense, and where orbital mechanics rather than aerodynamic principles govern movement.
The question of where space and outer space begin has a somewhat contested history. The Karman line at 100 kilometers is the most widely accepted international standard. It represents the altitude at which the atmosphere becomes too thin for conventional aerodynamic flight to work, meaning a vehicle would need to travel at orbital velocity to generate lift from the air. The US Air Force and NASA have historically used a lower threshold of 50 miles, or about 80 kilometers, as their definition. This is why some Virgin Galactic flights, which reached between 80 and 90 kilometers, were recognized by US authorities as space flights even though they fell short of the Karman line. Blue Origin explicitly crosses the 100 kilometer Karman line on every New Shepard mission. For most purposes when people talk about space and outer space in commercial tourism contexts, the Karman line is the agreed reference point.
The environment of space and outer space is extreme in ways that make Earth's most hostile environments seem mild by comparison. The vacuum of space means there is no air pressure and no breathable oxygen. An unprotected human in space would lose consciousness within seconds and face fatal exposure to the vacuum within minutes. Temperatures swing wildly depending on whether a surface is in direct sunlight or in shadow. In sunlight, temperatures can reach over 250 degrees Fahrenheit. In shadow, they can drop below negative 250 degrees Fahrenheit. Radiation from the Sun and from cosmic sources bombards everything in space without the protection of Earth's magnetic field and atmosphere. Micrometeoroids, tiny particles of rock and debris moving at extreme speeds, pose a constant risk to spacecraft. Despite these conditions, spacecraft are engineered to keep passengers in a safe, pressurized, temperature-controlled environment throughout the flight.
Spacecraft travel through space and outer space using principles quite different from those governing flight within the atmosphere. Inside the atmosphere, engines push against air. In the vacuum of space and outer space, there is nothing to push against, so rockets work by expelling exhaust gases in one direction, which propels the vehicle in the opposite direction. This is Newton's third law applied to the most extreme environment humans have ever operated in. For suborbital flights like New Shepard, the rocket fires during ascent and the vehicle then coasts through the top of its arc without any active propulsion. For orbital missions, the spacecraft must reach a speed of about 17,500 miles per hour to stay in a continuous free-fall around Earth. For deep space probes, the initial rocket launch sets a trajectory and gravity assists from planets are used to redirect and accelerate the vehicle over vast distances.
The dangers of space and outer space for humans are real and multiple but well-managed in commercial spaceflight contexts. Radiation is one of the primary long-term concerns for astronauts on extended missions. Without Earth's magnetic field and atmosphere as a shield, the body absorbs significantly more cosmic radiation, which increases cancer risk over time. For short suborbital trips, the radiation exposure is negligible. Vacuum exposure, temperature extremes, and micrometeoroid impact are managed through spacecraft design and pressurization. The physical effects of weightlessness, including fluid shifts, muscle atrophy, and bone density loss, are significant for long-duration missions but minimal for the brief suborbital experience. Reentry heat is managed through heat shield design. The overall safety architecture of commercial spacecraft like New Shepard is built around protecting passengers from all of these hazards throughout the flight. Open space travel companies invest enormously in this protection because passenger safety is the foundation of the entire commercial model.
Commercial travel to space and outer space currently operates at two levels. Suborbital flights, like those offered by Blue Origin's New Shepard, cross the Karman line for a brief arc and return to Earth in about 10 minutes. These require no orbital velocity and use a relatively simple vertical launch and landing profile. Orbital flights, like those arranged through Axiom Space using SpaceX's Crew Dragon, require reaching speeds of about 17,500 miles per hour to maintain orbit around Earth. These missions last days to weeks and involve significantly more preparation and cost. In both cases, the commercial model relies on reusable vehicles to reduce per-flight costs over time. Passengers purchase seats, go through training, and fly as private citizens. The FAA regulates all commercial launches from US soil. As technology continues to advance and competition increases, the range of commercial travel options to space and outer space will expand and become more accessible.
The long-term vision for living in space and outer space is something multiple companies and space agencies are actively working toward. Axiom Space is developing a commercial space station that will initially attach to the ISS before becoming an independent orbital facility. This could serve as a destination for extended tourist stays in orbit. NASA's Artemis program aims to establish a sustainable human presence on and around the Moon, including the Gateway lunar space station. SpaceX's Starship is being designed for missions to Mars, with the long-term goal of making humanity multi-planetary. Blue Origin's stated mission involves moving heavy industry off Earth to preserve the planet, with a vision of large orbital habitats housing millions of people. These are long-term goals measured in decades, not years, but the foundational work is happening right now. What is available in commercial space tourism today is the first chapter of a story that will unfold over the rest of this century.
https://www.travelosei.com/hello-india/open-space-travel
FAQs
Is there a difference between space and outer space in everyday usage?
In everyday conversation, the terms are used interchangeably to mean the region beyond Earth's atmosphere. In scientific contexts, outer space sometimes refers more specifically to the interplanetary or interstellar medium beyond any planetary atmosphere.
Does crossing the Karman line mean you have been to outer space?
By the most widely accepted international definition, yes. The Karman line at 100 kilometers is the recognized boundary of space, and crossing it qualifies as reaching space regardless of how briefly you are above it.
How does the absence of gravity in space affect the human body short-term?
Short-term effects include fluid shifts toward the head, mild facial puffiness, possible brief nausea, and spatial disorientation. These effects resolve quickly after returning to Earth's gravity, especially after a short suborbital flight.
Can humans survive in space and outer space without a spacecraft?
No. The vacuum, temperature extremes, and radiation of space are immediately and fatally hostile to unprotected humans. A pressurized suit or spacecraft is required at all times outside Earth's atmosphere.
What is the nearest object in outer space to Earth?
The Moon is Earth's nearest neighbor in space at an average distance of about 238,855 miles. It is the only other body in space that humans have visited in person, during the Apollo missions between 1969 and 1972.