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The environment in Space is a type of “weather” unlike the weather known to people on Earth who are accustomed to fog, snow, rain, sunshine, or wind. The location of Space is primarily outside the Earth’s protective atmosphere, and space travelers and their vehicles are subject to a very different environment, which may be just as harsh and possibly even more unsuspecting. The Earth is also protected by its own magnetosphere and travelling outside the magnetosphere poses yet another increased danger.

The stratum of Space refers to how the Space environment changes as one travels farther away from Earth. At 870 miles from Earth (Polaris Dawn mission) the radiation is greater than at 250 miles where the International Space Station is located due to the relative positions within the Van Allen radiation belt. These radiations were measured with sensors worn by crew members and within the spacecraft during the Polaris Dawn mission (September 2024). Travelling further puts one outside the protective magnetosphere of the Earth, posing yet another radiation danger. As travel continues farther from the Sun, the radiation then weakens because it spreads out into empty space. As we approach another star or planet, the stratum of space (or changes in weather) are experienced again, but in reverse order.

Currently, as we travel into Space, the “changes in weather” are referenced according to the distance from Earth, since we have not yet left the Solar System. Earth is also the reference for our celestial coordinates, the one and only home for human existence as we know it. Earth is where most telescopes are located.

High radiation is the danger to astronauts and equipment which comes from mainly two sources: 1) Solar particle events (SPE) from the Sun, and 2) Galactic cosmic rays (GCR).

High radiation is the danger to astronauts and equipment which comes from mainly two sources: 1) Solar particle events (SPE) from the Sun, and 2) Galactic cosmic rays (GCR). ¹ These radiations contain charged particles but become trapped in the Earth’s magnetic field (magnetosphere) and space vehicles in low-earth orbit, such as the International Space Station, remain protected. But outside the magnetosphere will subject travelers to these harsh radiations, such as a solar flare or prolonged exposure to galactic cosmic radiation. A violent solar flare causing a solar particle event (SPE) can kill an unprotected human in a single burst. Galactic cosmic rays propagate throughout all of Space, come from all directions, are random in nature, and pose a threat over a long duration, such as a trip to Mars. The origin of GCRs is a matter of scientific debate believing to have both galactic and extragalactic sources.

SPEs produce harmful X-rays, energetic particles, and solar plasma, but solar activity is constantly monitored by satellites which can allow a couple of hours warning if a solar particle event occurs. The X-rays reach Earth in minutes, the energetic particles in hours, and the solar plasma in days. The Apollo missions to the Moon relied on the low probability of SPEs during the three-day trip, but a mission to Mars will need at least a solar flare warning system and radiation protection within the spacecraft.

To protect against Galactic Cosmic Rays over a long duration, traditional shielding may not be effective, but an alternative is to design an active electromagnetic shield that acts as a “miniature magnetosphere” simulating the Earth’s magnetic field. It would bend the trajectory of charged particles away from the spacecraft. ¹

What the “weather in Space” may be implying to a Space traveler is that it is in his favor to travel to another planet with an atmosphere like the Earth. Although a trip to Mars is on the agenda for planetary travel, it lacks both a protective atmosphere and magnetosphere.

For nearby space activities, high-energy corpuscular radiation is most severe in the Van Allen radiation belts but can occur in any Space operation. A type of radiation is called a Single Event Upset (SEU). A single-event-upset occurs when a heavy ion is incident on a sensitive area of an integrated circuit - and can change the logic-state of the device. If the circuitry is related to a thruster control system, it can cause a random mis-firing of a thruster from a false command. Also, a burn-out can result from a single event latch-up which is the passage of a single charged particle leading to a latched low impedance state in parasitic PNPN devices.

Therefore it is possible that a Single Event Upset can cause random mis-firing of a spacecraft’s reaction control thruster, and then disable it (circuit burn-out).

The “wind’ in Space is the solar wind which is an outward flux from the Sun, a flow of plasma expelled at high velocity. It forms the outermost layer of the Solar System and is continously driven outward due to the Sun’s radiation pressure. At Earth, the speed of the solar wind is about 450 km/s, density about 9 protons/cm³, and kinetic temperature about 100,000 K.

Periods of high solar activity occur when there are a large number of sunspots, and enhanced emission of radiation generally takes place associated with solar flares at sites near sunspots.

Electrostatic charging of a spacecraft occurs when travelling through near-Earth space whether it is in or out of the radiation belts. Consequently, currents will occur between the spacecraft and the plasma, which imbalance can be returned to normal by arcing by using conductive surfaces wherever possible. For solar arrays, a coating of indium oxide is applied to the cell cover glass material to reduce the resisitivity of the glass surface.

Depending on the type of space mission, there is a frequency of micrometeoroids which are generally greater near large gravitational masses such as the Earth, or in the asteroid belt. This threat is increased by man-made space debris consisting of aluminum oxide dust particles (from solid rocket exhausts), instrument covers, nuts and bolts, rocket upper stages, or flakes of paint. Micrometeors and man-made debris led to the invention of a “meteor bumper” or “Whipple shield” invented by Fred Whipple in 1946. It consists of a relatively thin outer shield spaced a distance from the main spacecraft wall, intended to break up the meteor and disperse it into smaller fragments which the main wall can withstand.

Therefore it is possible that a Single Event Upset can cause random mis-firing of a spacecraft’s reaction control thruster, and then disable it (circuit burn-out).

Travelling further puts one outside the protective magnetosphere of the Earth, posing yet another radiation danger.

3. One other known radiation is the Cosmic Microwave Background Radiation (CMBR), which pertains more often to cosmology and less often to space travel, but at least lends evidence to the Big Bang Theory. With all the types of radiations in Space, ranging from galactic cosmic rays to solar particle events, the inter-relation of the magnetosphere with radiation belts, and the showers of micrometeorites, all against the backdrop of cosmic microwaves, it becomes overwhelming what exists in the Space environment although it is almost all invisible to the human eyes. The expression "the void of space" has certainly become a misnomer because Space is actually very full of its own type of weather, although it poses an unfamiliarity to an Earth person. Like the weather on Earth, if the sunshine invites us to go outside but rain causes us to open an umbrella for protection, the realm of Space draws us to its mysteries, but in the event of a solar flare for instance, we must take cover. To continue progress in Space, humans will need to gradually adapt and become familiar with the weather in Space the same as they have adapted the weather on Earth.