The most powerful companion. The brightest artificial satellites of the earth
We invite you to learn some interesting and educational facts about the satellites of the planets of the solar system.
1. Ganymede is a large satellite. This is the largest satellite not only of Jupiter, but also of the Solar system as a whole. He's so big. Which has its own magnetic field.
2. Miranda is an ugly companion. Considered the ugly duckling of the solar system. It seems as if someone cobbled together a satellite from pieces and sent it to revolve around Uranus. Miranda has some of the most spectacular scenery in the entire solar system, with mountain ranges and valleys forming intricate crowns and canyons, some 12 times deeper than the Grand Canyon. For example, if you throw a stone at one of these, it will fall only after 10 minutes.
3. Callisto is the satellite with the largest number of craters. Unlike other celestial bodies, Callisto does not have geological activity, which makes its surface unprotected. That’s why this satellite looks like the most “beaten one”.
4. Dactyl is an asteroid satellite. It is the smallest moon in the entire solar system, as it is only one mile wide. In the photo you can see the satellite Ida, and Dactyl is the small dot on the right. The uniqueness of this satellite lies in the fact that it does not orbit around a planet, but around an asteroid. Previously, scientists believed that asteroids were too small to have satellites, but as you can see, they were wrong.
5. Epimetheus and Janus are satellites that miraculously avoided a collision. Both satellites revolve around Saturn in the same orbit. They probably used to be one satellite. What is noteworthy: every 4 years, as soon as the moment of collision occurs, they change places.
6. Enceladus is the ring bearer. This is the inner satellite of Saturn, which reflects almost 100% of the light. The surface of Enceladus is filled with geysers that eject particles of ice and dust into space, forming Saturn's "E" ring.
7. Triton - with ice volcanoes. It is Neptune's largest satellite. It is also the only satellite of the solar system that rotates in the opposite direction from the rotation of the planet itself. Volcanoes on Triton are active, but they do not emit lava, but water and ammonia, which freeze on the surface.
8. Europe - with large oceans. This moon of Jupiter has the smoothest surface in the solar system. The thing is that the satellite is a continuous ocean covered with ice. There is 2-3 times more water here than on Earth.
9. Io is a volcanic hell. This satellite is similar to Mordor from The Lord of the Rings. Almost the entire surface of the satellite, which revolves around Jupiter, is covered with volcanoes, the eruptions of which occur very often. There are no craters on Io, as lava fills their surface, thereby leveling it.
11. Titan is a home away from home. This is perhaps the strangest satellite of the solar system. It is the only one that has an atmosphere that is several times denser than that of Earth. What was under the opaque clouds remained unknown for many years. Titan's atmosphere is based on nitrogen, just like Earth's, but it also contains other gases, such as methane. If methane levels on Titan are high, methane rain may occur on the satellite. The presence of large bright spots on the surface of the satellite suggests that there may be liquid seas on the surface, which may include methane. It is worth noting that Titan is the most suitable celestial body for searching for life.
On January 19, 2006, earthlings launched the “” probe, an automatic interplanetary station that will study Pluto, Charon and an object in the Kuiper belt. The full mission of the device is designed for 15-17 years. The "" left the vicinity of the Earth with the highest speed among known spacecraft - 16.26 km/s relative to the Earth. The heliocentric speed is 45 km/s, which would allow the device to leave the Solar System without a gravitational maneuver. However, there is an apparatus in this Universe created by human hands that flies even faster and has no equal in speed yet.
The two Voyager space probes have broken all records for distance traveled. They sent us photos of Jupiter, Saturn and Neptune and continue to move away from the solar system. On February 22, 2014, Voyager 1 was at a distance of about 19 billion kilometers from Earth and is still sending us data - it takes 10 hours from the probe to our planet. Several years ago, Voyager 1 left the solar system. How do probes manage to transmit data so far?
The Voyager spacecraft uses a 23-watt radio transmitter. This is more than usual mobile phone, but in the general order of things this transmitter is quite low-power. Large radio stations on Earth transmit tens of thousands of watts, but the signal is still quite weak.
The key to success, thanks to which the signal will reach regardless of the power of the radio transmitter, was a combination of three things:
- Very large antennas.
- Antennas directed at each other (Earth and Voyager).
- Radio frequencies with little interference.
The antennas that Voyager uses are quite large. You've probably seen satellite dishes among television lovers. They are usually 2-3 meters in diameter. Voyager's antenna has a diameter of 3.7 meters and transmits data that is received by a 34-meter antenna on Earth. Voyager's antenna and Earth's antenna are pointed directly at each other. The omnidirectional little antenna of your phone and the 34-meter giant are completely different things.
The Voyager satellites transmit data in the 8-gigahertz band, which is a frequency with little interference. The antenna on Earth uses powerful amplifier and receives a signal. After this, it sends a message back to the probe using a powerful transmitter so that Voyager is sure to receive the message.
On the front line
Voyager 1 has been transmitting data to Earth since 1977. But members of the team overseeing the mission at NASA's Jet Propulsion Laboratory recently gave us some interesting news. On September 12, 2013, NASA confirmed that the probe had entered the heliopause region, where the solar wind from our Sun is no longer strong enough to interfere with the solar winds of neighboring stars. At this moment, the “triaxial magnetometer” recorded a change in the magnetic field perpendicular to the direction of motion of the probe. Voyager 1 became the first man-made object to leave the solar system.
Voyager Golden Record: 117 images of Earth, greetings in 54 languages, Earth sounds
Cynics - like most astronomers, cosmologists and NASA itself - say that the edge of the solar system is defined as the point where an object is no longer subject to the sun's gravity. But gravity, as you know, determines the Universe on a huge scale. And this point is located at a distance 50,000 times greater than the distance from the Sun to the Earth. Voyager 1 traveled 123 distances from Earth to the Sun (approximately 18 billion kilometers). And it will take another 14,000 years for it to escape the gravitational capture of the Sun at its current speed.
There's nothing stopping the Voyager program from making great observations. Voyager 1 and its twin, Voyager 2, which departed 15 days earlier but was late due to an excursion to Uranus and Neptune, discovered traces of four gas giants and many strange astronomical phenomena. Although Voyager 1 remained within the solar system for some time, it entered a zone where charged particles from the solar wind would give way to dust and other materials filling the space between stars.
Over the years, Voyagers have discovered a number of astronomical surprises. One of the latest appeared in the summer of 2012, when Voyager 1 discovered a previously unknown phenomenon called the “magnetic highway.” In this region, as shown by instruments on board the probe, solar and interstellar magnetic fields collide. Edward Stone, Voyager's program director since 1972, explained that this occurs when low-energy particles within the "heliosphere" are replaced by higher-energy particles from space.
The creators of the probes hoped that they would be strong and durable enough to withstand all the vagaries of space. Especially during close approaches to Jupiter and Saturn, as well as excursions to Uranus and Neptune performed by Voyager 2. So when Pioneer 10 measured radiation around Uranus and Neptune in 1973 and found it to be higher than expected, Stone's team spent nine months replacing and rebuilding every element of the probe that might be damaged. Of course, the probes were designed with excess safety margins. For example, each of the probes carries two copies of three separate computer systems. But so far there are few on-board systems need a reboot. It's safe to say that Stone is paternally proud of his creation and its exploits.
The care with which the probes were made here on Earth also played a role in the success of the mission. When the primary and secondary receivers on Voyager 2 failed a year into the mission, the Earth crew activated backup system, which still works today. In 2010, after receiving a garbled message from the probe, the team performed a thorough memory dump using one of backup computers, and found out that one bit in the program had changed from 0 to 1. Rebooting the program fixed everything.
The team of scientists regularly updates the control system to ensure optimal use of the probes' resources during their active operation. During the Jovian phase of Voyager 1 alone, this was done 18 times. Let's take data communications, for example. When Voyagers orbited Jupiter and Saturn, the probes were close enough to Earth to send back uncompressed images and other data at relatively high bit rates: 115,000 and 45,000 bits per second, respectively. But because signal strength varies inversely with the square of the distance between transmitters, Voyager 2 transmitted data at a rate of 9,000 bits/sec during its exploration of Uranus. Neptune's number dropped to 3,000, thereby reducing the number of photos and data that could be sent home.
Most backup computers come online when the main one crashes. However, one of the auxiliary probe systems was activated and worked in conjunction with the main one. This allowed 640 kilobyte images of Uranus to be sent with loss of quality after being compressed to just 256 kilobytes.
As they say, everything ingenious is simple. Stone's team equipped the probes with advanced hardware called a Reed-Solomon decoder. The device significantly reduces the level of error that prevents the correct reading of messages in the event of loss of individual bits. Voyager initially used an old and well-tested system that sent one "error correction" bit for every bit in the message. The Reed-Solomon decoder rules one bit over five others. The funny thing is that in 1977, the Reed-Solomon method of decoding corrected data did not yet exist. Fortunately, by the time Voyager 2 reached Uranus in 1986, everything was ready.
The famous "Pale Blue Dot" image of Earth from 1990: Voyager 1's final mission. 6 billion kilometers
Currently, the data that comes from Voyagers to radio telescopes around the globe travels at a speed of only 160 bits per second. This decision was made deliberately to maintain a constant speed throughout the mission. The main cameras were turned off after the flyby of the last planet in the solar system, leaving only a few instruments active. Every six months, for 30 minutes, data from the 8-pin digital tape is transferred to a compressed archive at a speed of 1400 bits per second.
Radioisotope thermoelectric generators based on plutonium-238 will support the operation of instruments until at least 2021. And by 2025, after almost half a century of traveling to a place where there is nothing human, the team will turn off the probes and communicate with them in a slightly sentimental one-way manner to keep the Voyagers on their course. And they will fly further and further into the darkness.
Voyager 1 carries enough nuclear fuel to continue serving science until 2025, and then go with the flow after death. On its current trajectory, the probe should eventually end up 1.5 light-years away near the star Camelopardalis in the northern constellation, which looks like a cross between a giraffe and a camel. No one knows whether there are planets near this star and whether aliens will establish a residence there by the time the probe arrives.
The 20th century saw the emergence of space exploration using artificial satellites, space probes and manned spacecraft. Humans have come a long way since the launch of the first artificial satellite in 1957 and have sent several supermassive things into space. Here is a list of the seven largest objects in space sent from Earth.
- International Space Station (ISS)
The largest space station built by man, the ISS is larger than a football field and measures 109 meters long, 73 meters wide and weighs over 408,233 kg. The manned space station is an orbital laboratory where various scientific and space research, observations and experiments are carried out, and is the only artificial satellite that can be seen with the naked eye from planet Earth.
2. Hubble Space Telescope
Larger than two buses, the Hubble Space Telescope has been the largest in its category since 1990. The space telescope is more than thirteen meters long and weighs 12,247 kg.
3. Environmental satellite (Envisat)
The largest satellite that orbits the Earth, Envisat's monitors primarily monitor the Earth's atmosphere. The ten-meter satellite, weighing approximately 8,210 kg, is currently not operational, but is still in Earth orbit.
4. Orbital station "MIR"
The MIR orbital station was the first multi-module manned orbital station sent into space, measuring 33 meters long and 31 meters wide and weighing 140,160 kg.
5. Saturn V
Saturn V, measuring 104 meters tall and weighing 2,721,554 kg, was the tallest, heaviest and most powerful rocket. Saturn V completed 13 missions during its time span, from its launch in 1967 until 1973.
6. Skylab
Although Skylab is not as big as the one on the ISS, it was the first space station, which was sent from Earth. The space laboratory weighed almost 77,111 kilograms and orbited the Earth from 1973 to 1979.
