Space Facts Here you can find interesting tid bits about our solar system and manned and unmanned space flight. 
The Sun Mercury Venus Earth Mars Jupiter Saturn Uranus Pluto Moons Comets Solar System Misc Astronauts International Space Station Space Shuttle Spacecraft
Our Solar System The Sun The Sun looks 1,600 times fainter from Pluto than it does from the Earth. The Earth orbits the Sun at an average velocity of approximately 18 miles per second (30 kilometers per second). Plants closer to the Sun travel faster in their orbits and planets further away travel slower. The Sun is a fairly average star in terms of mass, temperature, and size. Comets' tails point away from the Sun at all times. Thus, when a comet is moving away from the Sun, its tail is actually leading. Comet tails are caused by dust and gas being lost from the comet and then pushed away from the Sun by the solar wind (charged particles moving out from the Sun) and by radiation pressure from the Sun. Due to frequent collisions with subatomic particles, it takes a typical gamma ray photon about one million years to travel from the core of the Sun to its surface, even though gamma rays travel at the speed of light (the gamma ray region of light has shorter wavelengths than X-rays). By the time the photon that started out as a gamma ray photon escapes the solar furnace, it has lost so much energy through collisions that it emerges from the Sun's surface as a photon of ordinary, visible light. Sunspots appear dark because they are cooler than the surrounding areas on the Sun, and therefore radiate less light and appear "dark" relative to the areas around them. Sunspot temperatures average about 3,800 degrees versus 5,800 degrees Celsius for the average surface of the Sun. Mercury Did you know that water ice may exist in the bottoms of craters at Mercury's poles, based upon radar data taken in recent years. Even though Mercury is the closest planet to the Sun, and extremely hot over most of its surface, ice may exist at the bottoms of some polar craters because the crater floors are permanently shadowed by the crater rims. Venus The surface of Venus is obscured by clouds at ultraviolet, visible, and infrared wavelengths, which is why the Pioneer and Magellan spacecraft used radar to penetrate the clouds and image the surface. The atmospheric pressure you would experience on the surface of Venus is approximately equal to the pressure you would experience 3,000 feet (~ 1 kilometer) down in the Earth's oceans, which is roughly 90 times the surface pressure found on Earth. Venus rotates very slowly. A Venus day is approximately 243 Earth days long. Venus is the brightest natural object in the sky besides the Sun and Moon. It can be as much as 15 times brighter than the brightest star (Sirius). All of the major features on the planet Venus are named after famous women in history and mythology. Earth Almost all of the oxygen in the Earth's atmosphere has been produced by living organisms. Oxygen accounts for 21% of our atmosphere, with nitrogen composing 78%, and a mixture of other gasses composing the remaining 1%. Oxygen only occurs as a minor constituent in the atmospheres of other planets in our Solar System. The Earth has the highest average density (5.52 gram/cubic centimeter) of any planet in our Solar System. Saturn has the lowest (0.69 gram/cubic centimeter). The density of liquid water is 1 gram/cubic centimeter. During a lunar eclipse, one can view the curved shape of the Earth's shadow, which is ground based evidence that the Earth is indeed round. Mars Did you know that liquid water does not currently occur on Mars because of the cold temperatures and low atmospheric pressures. Only water ice and water gas are stable. However, large channels on Mars appear to have been cut outflows of liquid water during Mars' distant past which may have had warmer temperatures and a much thicker atmosphere. The largest canyon system in the Solar System is Valles Marineris on Mars. It is more than 3,000 miles long and would stretch from California to New York. In some places it reaches a depth of 3 miles and 200 miles in width. The largest mountain in the Solar System is Olympus Mons, located on Mars. At a height of over 16 miles (26 kilometers), it is nearly 3 times taller than Mount Everest. Olympus Mons also has an enormous width of 360 miles (600 kilometers) across. Mars' surface area is approximately the same as the surface area of all the land on Earth. So, even though Mars is a smaller planet, studying its surface is just as a large of a task as studying all of Earth's land surfaces. Mars has two large-scale geologic regions. The "Southern Highlands," which cover a little more than half of Mars' surface, are composed of old (at least 3.9 billion years old) densely cratered terrain. The "Northern Plains" have lower and more variable crater densities, indicating that the plains are younger and formed over a much longer period of time. The cause of this Martian geologic dichotomy is not yet agreed upon. The gravitational force at the surface of Mars is only about one-third as strong as the gravitational force at the surface of the Earth. At its closet approach to Earth, Mars appears about as big as a tennis ball viewed from a distance of one and a half miles (2.25 kilometers). The main constituent of the Martian atmosphere, carbon dioxide, actually freezes on the surface of the planet during the winter, particularly in the polar regions. This can cause global atmospheric pressure changes. On Earth, water freezes outs, but is a minor constituent in the atmosphere. Jupiter Did you know that the most volcanically active body in solar system besides the Earth is Jupiter's moon Io. Erupting volcanoes were discovered on Io by the Voyager spacecraft. Jupiter's magnetosphere is the largest single structure inside the Solar System. If you could see it with your eyes, it would appear larger than our full Moon. Jupiter's moon Europa may have a liquid water "ocean" far beneath its water ice covered surface. The Great Red Spot on Jupiter is a hurricane-like storm system. It is large enough that two Earths could fit across it. The Red Spot has been around since at least the early 1600's when it was first detected shortly after the invention of the telescope. From the Jupiter-facing side of the moon Amalthea, Jupiter would fill up a huge chunk of sky, which is equivalent to going from the horizon to half way above the horizon. Jupiter's moon Io, less than 1/3 the size of Earth, puts out twice as much heat as the Earth. This is primarily due to tidal forces from Jupiter's enormous gravitational field causing a constant squeezing and stretching of Io. Heat generated by that squeezing and stretching accounts for Io being the most volcanically active body in the Solar System. Jupiter's moon Ganymede is the largest moon in the Solar System, and is larger than the planets Mercury and Pluto. A Jupiter day, the time required for the planet to rotate once, is only about 10 hours long, Jupiter has the shortest day (rotational period) of any planet in the Solar System. Europa, covered with mostly water ice, has the smoothest surface of any large object in the Solar System. this satellite of Jupiter has a mostly flat surface, with no discovered topographic relief larger than 1 kilometer (0.6 miles) in height, even though Europa has an intricate set of cracks criss-crossing its icy surfaces. Jupiter's moon Ganymede, the largest moon in the Solar System, has a surface area that is approximately half that of Earth's land surface area (not including Earth's oceans). Jupiter's core is thought to consist primarily of metallic hydrogen. Saturn All four giant planets (Jupiter, Saturn, Uranus, and Neptune) have ring systems. As of 20 years ago, only Saturn was known to have rings. Saturn's ring system is by far the largest and most developed of the four. If all the particles that make up Saturn's rings were gathered together, they would form a sphere about 120 miles in diameter, roughly the size of Saturn's seventh largest moon, Mimas. Uranus Methane gas, which absorbs red light, is what causes Uranus and Neptune to look bluish in color. Methane is a relatively minor constituent of their atmospheres, however. Like Jupiter and Saturn, Uranus and Neptune have atmospheres made mostly of hydrogen and helium. The planet Uranus was discovered by the eminent English astronomer William Herschel in 1781. He briefly considered naming the planet George in honor of England's King George III. Pluto Distance of Pluto's orbit varies from 26 to 52 AU. Marking Pluto as the only planet that possesses a highly erratic orbit. Pluto's elliptical orbit sometimes brings it inside of the orbit of Neptune for a few years. On average, the distance from Pluto to the Sun is approximately 40 times the distance from the Earth to the Sun. Put a different way, if a scale model were constructed with the Sun on the California coast and the Earth about 75 miles inland, then on the same scale Pluto would be in New York. Moons Did you know that some of the moons in our Solar System are larger than some of the planets? Jupiter's moon Ganymede, which is the largest moon in the Solar System, and Saturn's moon Titan are both larger than the planets Mercury and Pluto. The Earth's Moon, Jupiter's moons Callisto, Io, and Europa, and Netptune's moon Triton are all larger than Pluto, however, they are smaller than planet Mercury. If you added up the mass of all of the thousands of known asteroids in the asteroid belt, the total would be less than ten percent the mass of the Earth's moon. Our moon has only one eightieth the mass of the Earth. A Blue Moon is the second of two full Moons that fall within the same month. This can occur because full Moon's occur roughly every 29.5 days. A Blue Moon occurs roughly every two and three-quarter years. The Moon actually appears much brighter than the Sun at gamma ray wavelengths. Comets As comets Hale-Bopp is putting out approximately 250 tons of gas and dust per second. This is about 50 times more than most comets produce. As comets approach the Sun, their tails can become long enough that they stretch from one planet's orbit across the orbit of another planet. For the first 100 million years or so after the formation of the solar system, a bright, naked-eye comet was visible in the skies of Earth roughly once a week. Based upon data from the International Ultraviolet Explorer (IUE) satellite, Comet Hyakutake was found to be ejecting ten tons of water every second as it passed near the Sun. Solar System Misc There are 10 million trillion atoms in one cubic centimeter (cc) of air at sea level (on Earth), while there is 1 atom per cc in the gap between the stars and only 1 atom for cubic meter (cm) in the void between galaxies. Distance from the Earth to the moon is 238,774 miles. Distance of the Earth to the Sun is 93,150,000 miles (or 1 AU). Speed of Light is 186,170 miles per a second (1 AU = 8 minutes at the Speed of Light) Light travels about 5.9 trillion miles in 1 year (1 Light Year = 65,555 AU). The Milky Way Galaxy is 90,000 Light Years wide and 3,000 Light Years thick. The nearest star, Alpha Centauri is roughly 4.3 Light Years away. There are an estimated +400 billion stars in the Milky Way Galaxy. Estimated number of galaxies in the universe is +50 billion. Estimated number of stars in the universe is 5 trillion. The universe is estimated to be 14 to 16 billion years old, while the Earth is only 5 billion years old. Size comparisons: About 1,000 Earths would fit inside Jupiter, and about 1,000 Jupiters would fit inside the Sun. Our Solar System, by virtue of its proper motion through our galaxy (the Milky Way) is moving at a speed of 43,000 miles per hour toward the globular cluster of stars known as M13 in the constellation Hercules. Some of the objects visible in Hubble Space Telescope (HST) images are nearly four billion times fainter than the limits of human vision. Comet Hyakutake's orbit will carry it over 1,000 astronomical units from the Sun before it once again heads back towards the Sun in another 7,000 years. (1 Astronomical Unit equals the average distance from the Sun to the Earth, which equals 93 million miles or 150 million kilometers) Such large orbits are not unusual for long-period comets. For comparision, Pluto is on average 40 astronomical units from the Sun and orbits the Sun once every 248 years. If you suspend three grains of sand in a large sports arena, the arena will be more closely packed with sand than our galaxy is with stars. A beam of light travels just over twelve inches in one nano-second (a billionth of a second). The elements Carbon, Hydrogen, Oxygen, and Nitrogen are all crucial to life. These elements are found in roughly the same proportions in comets and human beings. The first experimental confirmation of Einstein's General Theory of Relativity was made during the total solar eclipse of May 29, 1919. During an eclipse, bright stars become visible. Einstein had predicted that gravity from the Sun would slightly bend the path of starlight passing close to the Sun. Astronomers tested this assertion by measuring the positions of several stars that appeared close to the Sun during the 1919 eclipse. The deviations in the observed positions of these stars due to the Sun's gravity matched Einstein's predictions. The average distance between stars in the spiral arms of the Milky Way galaxy is currently estimated to be seven light years (66 trillion kilometers). This distance is equal to roughly 443,000 times the distance between the Earth and Sun. Space Flight Astronauts Story Musgrave is the only astronaut to have flown into space on board all five Space Shuttles (including Challenger). The first American to eat food in space was Scott Carpenter aboard the Mercury spacecraft Aurora 7 in 1962. The last astronaut to fly in space alone in a spacecraft was Apollo 17 command module pilot Ron Evans, who circled the Moon alone while astronauts Gene Cernan and Harrison Schmitt went to the surface. Only 12 humans have ever visited another world - all of them walking on the Moon during brief stays between July 20, 1969 and Dec. 13, 1972 as part of the Apollo program. International Space Station Fifty-two computers will control the systems on the International Space Station. There will be more than 400,000 lines of software for 16 of those computers which, in turn, will communicate with 2,000 sensors, effectors and embedded "smart" hardware controllers. While two computers in the U.S. Laboratory module are dedicated to keeping the station in proper orientation (attitude) as it orbits the Earth once every 90 minutes. Twenty two computers mounted outside the station control such functions as electrical power switching, solar panel alignment, disposal of heat generated from the station's environment and electronic equipment, and a mobile transporter that travels along a rail the length of the station. The flight support software has 1.7 million lines of code (includes test control and simulation software). The ISS requires the partnership of 17 nations- the United Kingdom, the United States, the Netherlands, Canada, Japan, Russia, Brazil, Belgium, France, Germany, Denmark, Italy, Norway, Spain, Sweden, and Switzerland. This in fact has become the largest non-military joint project in history. The ISS will have a mass of over one million pounds, that makes it five times the mass of the first space station, Skylab. The ISS will be able to run 18,000 rack days in a year, while only Skylab could run 392 rack days in a year (based on energy in a kWh/ year). There are four U.S. photovoltaic modules, each with two arrays measuring 112 feet long by 39 feet wide. Each module generates about 23 kW. They rotate to face the sun, which provides maximum power to the station. The solar array surface area is 27,000 square feet, or more than half an acre. The thermal radiator (heat reflection for the four PV modules) area covers 2,200 square feet. The electric power system is connected with 42,000 feet, or eight miles, of wire. The batteries, lined up end-to-end, measure 2,900 feet, or 1/2 mile long. The total weight of electric power system hardware is 140,000 pounds or 70 tons. Electrical and electronic parts include 1,900 different types of resistors, 500 types of capacitors, 150 types of transistors (note that this is not the part count, rather, it is a count of different types of hardware). Hauling the parts into space will require the flight of 45 space flights, made up of the U.S. Space Shuttle (STS), Russian Proton and Soyuz rockets. A Canadian built Remote Manipular System (RMS), which is a 58-foot robot arm and a special grappling device called the Special Purpose Dexterous Manipulator (SPDM), will move along the stations' truss to perform assembly and maintenance work. The RMS can move objects that would weight as much as 220,000 lbs on Earth. The 12-foot SPDM can move lighter objects of up to 1,300 lbs with finer precision. There will be a total of at least eight scientific laboratories. The US will provide one lab and a habitation module that will replace the Service Module's early crew living quarters. There will be two Russian research labs, a Japanese laboratory called the Japanese Experiment Module (JEM) and a European Space Agency (ESA) laboratory called the Columbus Orbital Facility (COF). The station will have four windows for observing the Earth to conduct Earth observation experiments and other applications. It will also have 11 external payload locations for mounting experiments. The ISS will be a state-of-the-art, multipurpose laboratory. It will provide discovery in the fields of science, technology, and commercial values. The research labs will be used to work on the following fields of science: Gravitational Biology, Biotechnology, Fluid Physics, Combustion Science, Material Science, Fundamental Physics, Biomedicine, Space Sciences, and Earth Sciences. Space Shuttle Amazingly the shuttle program returns the highest return on investment (ROI) of any national program in history. For every one dollar spent on the program the taxpayers (you and me) receive up to nine dollars fed back into the economy. Every taxpayer owns the U.S. Space Shuttles and pay less then one cent a day for all three, that is far cheaper than owning a bike, car, or a boat. The space program has and continues to become the main stepping stone for international cooperation between the former Cold War countries, with the U.S. Space Shuttle and the former Russian Space Station Mir making many historical sorties that bridged the two countries together into the International Space Station (ISS) project. Even though the Space Shuttle is a product of 1970' s technology it is still highly valued due to its incredible versatility and durability. The current shuttle roster consist of three: Endeavor, Discovery, and Atlantis. There were three more U.S. Space Shuttles one of which was Enterprise, which was used for flight testing only, and the other two were lost while in service with the STS- 51L Challenger which tragically exploded during liftoff and STS-107 Columbia which disintegrated upon re-entry. Payload accommodates anything from Getaway Specials to deployable/retrievable spacecraft to fully equipped scientific labs. The payload can hold up to 55,000 lbs and it is flexible and user responsive. The payload bay is, in fact, large enough to accommodate a tour bus. Space Shuttle reliability is 98.13% (making it the highest success rate of any existing space vehicle) and lifting off on projecting launch time occurs 43% of the time. The shuttle program was capable of carrying out twelve shuttle flights in a year and features mature support and maintenance infrastructure. There were as many Shuttle flights in five years as there were manned Mercury, Gemini, and Apollo missions flown over the course of ten years. The STS also carried twice the number of astronauts during half the time period. This is what the Space Shuttle can do: transport people and cargo to and from Low Earth Orbit (LEO), maneuvering people and cargo on orbit, abort capability insures high-value payloads, performing various low Earth orbit sortie missions. It only takes the Space Shuttle about 8 minutes to accelerate to its orbital speed of more than 17,000 miles per hour. The Space Shuttle main engine weighs 1/7th as much as a train engine, but delivers as much horsepower as 39 train engines. A Space Shuttle and its boosters ready for launch are the same height as the Statue of Liberty but weigh almost three times as much. Each of the Space Shuttle's solid rocket boosters burns 5 tons of propellant per second. NASA's Compton Gamma Ray Observatory, launched in 1991 aboard the Space Shuttle Atlantis, is the heaviest spacecraft ever deployed by a Space Shuttle. The Space Shuttle flies about 200 miles (330 kilometers) above the Earth's surface (equivalent to roughly half the distance between Los Angeles and San Francisco). In contrast, geostationary (stationary with respect to the Earth's surface) communications satellites have to be lofted approximately 21,500 miles (35,800 kilometers) above the Earth's surface, and the Apollo spacecraft were approximately 227,000 miles (378,000 kilometers) above the Earth's surface when they reached the Moon. The Solid Rocket Boosters (SRBs) used during Space Shuttle launches are the largest solid-propellant motors ever flown and the first designed for reuse. Each is 149.16 feet long and 12.17 feet in diameter. The speed required for a spacecraft or other object to completely escape the gravitational pull of the Earth (escape velocity) is approximately 11 km/s (7 mi/s), or about 40,000 km/hr (25,000 mi/hr). Each Space Shuttle Solid Rocket Booster (SRB) has a thrust of approximately 3,300,000 pounds at launch. The propellant mixture in each Space Shuttle Solid Rocket Booster (SRB) consists of ammonium perchlorate (oxidizer, 69.9 percent by weight), aluminum (fuel, 16 percent), iron oxide (a catalyst, 0.4 percent), a polymer (a binder that holds the mixture together, 12.04 percent), and an epoxy curing agent (1.96 percent). During launch, the main engines of the Space Shuttle use liquid hydrogen and liquid oxygen, which are stored in the large, expendable central fuel tank, referred to as the External Fuel Tank (ET). During landing of a space shuttle, it takes approximately one minute between touchdown of the wheels and wheelstop, the point at which the shuttle comes to a complete stop. Spacecraft Pioneer 11's speed going past Jupiter was over 107,000 MPH, the fastest speed ever traveled by a human-made object. At almost six billion miles away, Pioneer 10 is the most distant object built by humans. The Galileo probe, weighing in at 339 kilograms (750 pounds), entered Jupiter's atmosphere at 170,000 kilometers per hour (106,000 mph), or more than 50 times faster than a bullet shot out of a rifle. The probe will experience deceleration forces as high as 230 times Earth's gravity. In about two minutes, the orbiter's speed will be slowed to about 1,600 kilometers per hour (1,000 mph). The amount of power transmitted by the Galileo spacecraft's radio is about the same amount used by a refrigerator light bulb - about 20 watts. By the time they reach Earth, the radio signals from Galileo are incredibly weak (about a billion times fainter than the sound of a transistor radio in New York as heard from Los Angeles). The average radiation dose per minute absorbed by the Galileo spacecraft during its orbital mission is equivalent to what the average person receives in a whole year on Earth. On December 7, as it made its closest approach to Jupiter, the radiation dose per minute to Galileo exceeded by several times what a person on Earth would receive in their entire lifetime and would have been quite lethal to a human. The Voyager spacecraft delivery accuracy at Neptune (100 kilometers or 60 miles), divided by the trip distance of 7,128,603,456 kilometers (4,429,508,700 miles), was the equivalent of sinking a 3630 kilometers (2260 miles) golf shot, although Voyager, as opposed to a golf shot, was allowed a few minor trajectory adjustments along the way. It takes radio signals from Earth (traveling at the speed of light: 186,000 miles per second) approximately 9 hours to reach the Pioneer 10 spacecraft, which is the most distant object built by humans. It takes another 9 hours for the spacecraft's response to reach Earth. It currently takes radio signals approximately 35 minutes to get from the Galileo spacecraft to Earth. Galileo, in orbit around Jupiter, is over 635 million kilometers (about 395 million miles) from Earth. The Galileo spacecraft traveled 2.4 billion miles on its way to Jupiter and along the way used about 67 gallons of fuel to control the flight path and spacecraft attitude. This is the equivalent of about 36 million miles per gallon, although Galileo's usage of fuel was not at all continuous, but rather occurred in discrete bursts. Viking Lander 1 was originally scheduled to land on July 4, 1976. However, the landing was delayed and the site adjusted because the original site appeared too hazardous in Viking Orbiter photographs. Landing occurred July 20, 1976, seven years after Apollo 11 landed on the Moon. Mariner 10 was the first spacecraft to encounter two planets (besides Earth) on one mission. It flew past both Venus and Mercury in the early 1970's. The Mars Pathfinder rover, named Sojourner, is 63 cm (25 in) long and 48 cm (19 in) wide, and weighs approximately 12 kg (25 lb). **Some of the preceding information is provided by the Planetary Science Institute, which can be found here http://www.psi.edu.** | 
