Back to School - Basics of Space Flight - PART1 - Solar System

- Back to school –

The world of “Infinity” promises to use real, Newton physic, real solar systems with modeled orbits, gravity, simulated celestial objects, stars, galaxies and hundreds of light years of travel between undiscovered worlds.
Ask yourself a question; “am I prepared for all this?”
Do I really know anything about real space travel? How gravity can help me to escape another wave of enemy fighters?
Do I know what I have to do to reach another planet?
Most of us forgot how real space looks like, we have a vision of planets displayed as a flat bitmap where you can just flight straight through to the another side without worry about orbital mathematics and gravity (sorry EVE-Online, you are crap in this matter).

So, my idea is to give you some basics of a space flight, solar system generic overview. I would like to teach you some facts about gravity and space mechanics, trajectories, orbits, navigation and many other things.

The only question is; do you want to read all these boring things? :-)
I know that we want to kill as many heretics of our Empire as possible for the glory of The Sovereign. But sometimes is good to know why my space ship is flying straight to the face of White Dwarf while I cut off the engines and trying to turn it around.
So, let me start my first article about Basics of Space Flight, material is gathered from official library of NASA and slightly edited by me.
If you find this topic too boring, please let me know. Any comments are appreciated.

PART 1 – The Solar System – basics of the concept.

The solar system has been a topic of study from the beginning of history. For nearly all that time, people have had to rely on long-range and indirect measurements of its objects. For all of human history and pre-history, observations were based on visible light. Then in the 20th century, people discovered how to use additional parts of the spectrum. Radio waves, received here on Earth, have been used since 1931 to investigate celestial objects. Starting with the emergence of space flight in 1957, instruments operating above Earth's obscuring atmosphere could take advantage not only of light and radio, but virtually the whole spectrum. At last, with interplanetary travel, instruments can be carried to many solar system objects, to measure their physical properties and dynamics directly and at very close range. In the 21st century, knowledge of the solar system is advancing at an unprecedented rate.

The solar system consists of an average star we call The Sun, its "bubble" the heliosphere, the classical planets Mercury, Venus, Earth, Mars, Jupiter, and Saturn which were known to the ancients, and Uranus and Neptune, as well as the dwarf planet Pluto, which is one of a number of objects in the Kuiper Belt. The solar system includes the satellites of the planets, numerous comets, asteroids, meteoroids, and the interplanetary medium, which permeates interplanetary space. The dwarf planet Ceres is a member of the main belt of asteroids. The Oort cloud, a vast reservoir of comet nuclei, marks the farthest extent of the Sun's practical gravitational influence, out to about 3 light years from the Sun.

Interstellar space - is the term given to the space between stars in the galaxy. The Sun's nearest known stellar neighbor is a red dwarf star called Proxima Centauri, at a distance of about 4.2 light years (a light year is the distance light travels in a year, at about 300,000 km per second). We are beginning to find that many stars besides the Sun harbor their own "solar systems" with planets, which are being called extrasolar planets, or exoplanets. As of December 2007, astronomers have detected a total of 270 planets orbiting other stars. This number is up from the milestone of 100 exoplanets discovered as of January 2004. Most known exoplanets are gas giants, Jupiter-like planets, since current methods favor the detection of the more massive worlds. Most are relatively nearby, within 5,000 light years, although one candidate was discovered in September 2005 at a distance of 17,000 light years.

In Cosmic Perspective
Our whole solar system, along with all the local stars you can see on a clear dark night, sit in one of our galaxy's spiral arms, known as the Orion arm, as they orbit the supermassive black hole in the dense star cluster at the center of our galaxy some 26,000 ± 1400 light-years distant from us. At this great distance, we go around once about every 250 million years. Stars very close to the central mass are observed in keplerian orbits with periods as short as 15.2 years. This spiral disk that we call the Milky Way includes some 200 billion stars, thousands of gigantic clouds of gas and dust, and enormous quantities of mysterious dark matter.

The Milky Way has two small galaxies orbiting it nearby, which are visible from Earth's southern hemisphere. They are called the Large Magellanic Cloud and the Small Magellanic Cloud.

Our galaxy, one of billions of galaxies known, is traveling through intergalactic space. On a cosmic scale, all galaxies are generally receding from each other, although those relatively close together may exhibit additional local motion toward or away from each other as well.

Aside from its galactic orbital velocity (250-300 km/second), the Sun and its planetary system wander through the local stellar neighborhood at roughly 100,000 kilometers per hour, entering and leaving various tenuous local clouds of gas on a time scale of roughly once every few thousand to millions of years.

Immediately surrounding our solar system is a warm, partly ionized cloud, called the Local Interstellar Cloud. Like most interstellar clouds, its gas comprises about 90% hydrogen and 10% helium. Roughly 1% of the cloud's mass is dust.

Motions Within the Solar System
The Sun and planets each rotate on their axes. Because they formed from the same rotating disk, the planets, most of their satellites, and the asteroids, all revolve around the Sun in the same direction as the Sun rotates, and in nearly circular orbits. The planets orbit the Sun in or near the same plane, called the ecliptic (because it is where eclipses occur). Pluto is a special case in that its orbit is the most highly inclined (17 degrees) and the most highly elliptical of all the planets. Its orbit is more typical of a Kuiper Belt Object. Because its orbit is so eccentric, Pluto sometimes comes closer to the Sun than does Neptune. Most planets rotate in or near the plane in which they orbit the Sun, again because they formed, rotating, out of the same dust ring. The exception, Uranus, must have suffered a whopping collision that set it rotating on its side.

Distances Within the Solar System
The most commonly used unit of measurement for distances within the solar system is the astronomical unit (AU). The AU is based on the mean distance from the Sun to Earth, roughly 150,000,000 km. JPL's Deep Space Network refined the precise value of the AU in the 1960s by obtaining radar echoes from Venus. This measurement was important since spacecraft navigation depends on accurate knowledge of the AU. Another way to indicate distances within the solar system is terms of light time, which is the distance light travel in a unit of time. Distances within the solar system, while vast compared to our travels on Earth's surface, are comparatively small-scale in astronomical terms. For reference, Proxima Centauri, the nearest star at about 4.2 light years away, is about 265,000 AU from the Sun.

Light Time	Approximate	Distance Example
3 seconds	900,000 km	~ Earth-Moon Round Trip
3 minutes	54,000,000 km	~ Sun to Mercury
8.3 minutes	149,600,000 km	Sun to Earth (1 AU)
1 hour	1,000,000,000 km	~ 1.5 x Sun-Jupiter Distance
14.5 hours	105 AU	Voyager-1 (January, 2008)
1 year	~ 63,000 AU	Light Year
4.2 years	~ 265,000 AU	Next closest star

The Sun
The Sun is a typical star. Its spectral classification is "G2 V." The G2 part basically means it's a yellow-white star, and the roman numeral V means it's a "main sequence" dwarf star (by far the most common) as opposed to supergiant, or sub-dwarf, etc. The Sun is the dominant source of energy for processes on Earth.

Mass:
The Sun dominates the gravitational field of the solar system. The motion of everything within a few light years of the Sun is dominated by the effect of the solar mass. At 1.98892 X 1030 kilograms, or roughly 333,000 times the mass of the Earth, it contains over 99 percent of the solar system's mass. The planets, which condensed out of the same disk of material that formed the Sun, contain just over a tenth of a percent the mass of the solar system.

Fusion:
The Sun's gravity creates extreme pressures and temperatures within its core, sustaining a thermonuclear reaction fusing hydrogen nuclei and producing helium nuclei. This reaction converts about 4 billion kilograms of mass to energy every second. This yields tremendous amounts of energy, causing the state of all the Sun's material to be plasma and gas. These thermonuclear reactions began about 5 billion years ago in the Sun, and will probably continue for another 5 billion years into the future. Energy produced in the core takes over a million years to reach the surface and be radiated as light and heat.

Rotation:
The Sun rotates on its axis with a period of approximately 25.4 days. This is the adopted value at 16° latitude. Because the Sun is a gaseous body, not all its material rotates together.

Magnetic Field:
Magnetism is produced in the Sun by the flow of electrically charged particles: ions and electrons. Not surprising, the Sun's magnetic field permeates interplanetary space. The magnetic field of the Sun influences the way in which charged particles (cosmic rays, solar energetic particles, and even interstellar dust grains) move through the heliosphere.

Mass Ejections:
Coronal mass ejections, CMEs, are huge magnetic bubbles of plasma that expand away from the Sun at speeds as high as 2000 km per second. A single CME can carry up to ten billion tons of plasma away from the Sun.
When a CME arrives at Earth, it can cause fluctuations in the Earth's magnetic field that can play havoc with the civil electrical power distribution infrastructure, by inducing unwanted voltages.

Solar Wind:
The solar wind streams off of the Sun in all directions. The source of the solar wind is the Sun's hot corona, whose temperature is so high that the Sun's gravity cannot hold on to it.

-- The End --


gathered and edited for your viewing pleasure by
Engineer and Explorer of the Empire
Xargh

simply fantastic. please bring more of these posts. this is what we need and will be extremely useful.

As you wish, Your Highness, next lesson on the way!