Against the backdrop of daily news about how another private space company launched its first (second, third, and so on) rocket, took cargo to the ISS, prepares to open the space tourism season, and is also making plans to colonize the nearest neighboring planets, news from the big state space agencies somehow start to get lost. In the meantime, we recall that the NASA aerospace agency has launched a very ambitious mission to explore the Sun.
On August 12, 2018, a Delta IV Heavy rocket was launched from the US Air Force Base at Cape Canaveral in Florida. The cargo is a solar probe "Parker", whose task is to overcome nearly 150 million kilometers of outer space and rendezvous with the Sun. Parker will have to get as close to the star as no spacecraft has ever gotten to it. On the way to the Sun, the probe will carry out several gravitational maneuvers around Venus, becoming, according to NASA forecasts, the fastest man-made object in space. Today we'll talk about the 10 most interesting facts related to this mission.
Touch the sun
The Parker Solar Probe is tasked with a mission that no man-made spacecraft could have accomplished before. He will study the outer atmosphere of the Sun. The so-called crown. To do this, he will get close to the star at a distance of 6.2 million kilometers, in fact, "touching" the outer layer of its atmosphere. The device will deal not only with solving the mysteries of the star, but will also add to our knowledge of how the Sun affects the magnetosphere of our planet. The importance of this mission can hardly be overestimated, since technologies become more and more widespread, which in one way or another are influenced by the activity of our Luminary. It is possible that this mission will increase our ability to study the solar system as a whole.
50 years of preparation
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The launch of the probe in August 2018 was the culmination of more than 50 years of development and planning for this space mission. The scientific community found out that the temperature of the solar corona can reach a million degrees Celsius back in the 40s of the last century. Confirmation of the existence of the so-called solar wind (highly charged ionized plasma particles ejected by the corona) took place in the 60s. However, scientists still cannot understand why the temperature of the sun's corona is much higher than the temperature of the star's surface. In addition, it is not clear what exactly accelerates the particles of the solar wind. The answers to these questions can only be obtained through direct contact with the solar corona, the researchers say.
The idea to conduct such a study was first proposed back in 1958. Since then, several spacecraft have approached the Sun, but none of them have approached the star as closely as predicted to do the Parker solar probe.
NASA's first spacecraft named after a living person
The NASA aerospace agency has given its spacecraft a variety of names, but none of them was named after a still living person. The Parker Solar Probe is named after astrophysicist Eugene Parker, who predicted the existence of the solar wind in 1958.
In the 1950s, Parker developed a complex theory about how stars give up their energy. He introduced the concept of "solar wind" to describe the cascading emissions of energy from the Sun and even proposed a theory explaining the reason for the higher temperature of the solar corona compared to the surface of the star. In addition, the astrophysicist considered a model of the external atmosphere of the Sun with a constant outflow of matter from the corona and showed that the solar wind speed increases with distance from the Sun, reaching supersonic values. The scientist also analyzed the effect of the expanding corona on the magnetic field in the vicinity of the Sun and found that the field must be spiral due to the rotation of the Sun. His conclusions about the speed of the solar wind and the spiral structure of the solar magnetic field were subsequently confirmed using spacecraft. Parker is now 91 years old. Despite his age, on August 12, on the day of the launch of the probe, the astrophysicist was present at the launch complex.
sunny wind
The mission's main scientific objectives will generally center around the secrets associated with the solar wind. Gusts generated inside the crown can reach speeds of 1.6 million kilometers per hour. NASA scientists hope to figure out why the solar corona is so hot and what exactly is accelerating the solar wind. These things cannot be figured out without finding the mechanisms responsible for these processes near the source.
The sun is very difficult to reach
In fact, going to the Sun requires 55 times more energy than going to Mars. First, the distance from Earth to our star is about 150 million kilometers. But distance isn't the only problem here. The main problem here is the so-called lateral speed, that is, the speed relative to the desired motion vector.
To understand the principle of lateral velocity, it is necessary to understand how bodies move in orbits. In fact, all objects in the orbit of the Sun fall on the star endlessly. However, the lateral speed does not allow them to fall, since they actually overtake the body they are falling on. The Earth moves around the Sun at a speed of 108,000 kilometers per hour. As a result, when the spacecraft leaves the Earth's orbit, it will move forward in space and start falling on the Sun, but it will constantly miss, since its lateral velocity will remain. In order to get to the star, the device simply needs to fall.
To address the issue of lateral velocity, NASA plans to use gravity assist maneuvers around Venus. They will make it possible to almost completely extinguish this indicator, but at the same time they will increase the maximum speed of movement of the Parker Solar Probe, which at its peak can be up to 200 kilometers per second.
Gravitational maneuvers around Venus
To get as close as possible to the Sun, the Parker Solar Probe will have to perform several gravity assist maneuvers around Venus over the next 7 years.
After the first flyby of Venus, the probe will enter an elliptical orbit with a period of 150 days (2/3 of the Venus period), making 3 orbits when Venus makes 2. After the second flyby, the period will decrease to 130 days. In less than 2 orbits (198 days), the spacecraft will meet Venus for the third time. This will shorten the period to half that of Venus (112.5 days). For the fourth meeting, the period will already be 102 days. After 237 days, the probe will meet Venus for the fifth time, and the rotation period will be reduced to 96 days (3/7 of Venus). The apparatus at this moment will already make 7 revolutions, when Venus will only make 3. The sixth meeting will take place almost two years after the previous one and will shorten the period to 92 days (2/5 of the Venusian). After another five revolutions around the Sun, the probe will meet Venus for the seventh and last time, which will reduce the period to 88-89 days.allowing you to come even closer to the sun.
The fastest spacecraft in human history
Thanks to several gravity assist maneuvers around Venus, the spacecraft will eventually be able to reach speeds of 692,000 kilometers per hour, faster than any other space probe built by man.
At this point in time, the fastest spacecraft is the probe "Juno", designed to study Jupiter. Its current speed is about 266 thousand kilometers per hour. The speed of the Voyager 1 spacecraft, launched to conquer interstellar space in the late 1970s and leaving the solar system 35 years later, is approximately 61,000 kilometers per hour. The maximum speed of the Parker Solar Probe will more than double that of Juno and 11 times that of Voyager 1.
Heat shield
The heat shield of the probe is just as impressive as its top speed. The size of the solar shield located in the front of the apparatus is 2.4 meters in diameter. It is designed to reflect extreme heat from the scientific equipment of the probe. The screen is 11.5 centimeters thick. It consists of carbon composite foam sandwiched between two carbon plates. The front plate facing the sun is covered with a special white ceramic paint that reflects heat as efficiently as possible. The materials used made the shield quite light. Its weight is only 73 kilograms.
In space, the temperature can be thousands of degrees, but a particular object will not heat up because temperature is determined by the speed of the particles, whereas heat is measured by the total amount of energy they carry. Particles can move quickly (high temperature), but if there are few of them, then there will be little energy (little heat). There are few particles in space, so few of them are able to transfer energy to the apparatus.
The most autonomous spacecraft
One explanation for the effectiveness of the heat shield lies in the very “smart” software that controls the spacecraft. When the probe is near the Sun, the connection between it and the Earth will be unilaterally interrupted every 8 minutes. During this time, the probe will be able to independently make the necessary adjustments in just 10 seconds.
The creators of the probe have introduced into its software absolutely all possible scenarios of the development of events that they could imagine, so the device is able to independently change the angle of inclination and rotation of the protective screen if necessary.
Nicola Fox, a research associate for the Parker Solar Probe Project, calls the craft "the most autonomous spacecraft ever made by man."
Unique cargo
In March this year, NASA invited the public to take part in an action in which the names of hundreds of thousands of participants will be placed on a commemorative plaque and sent to the Sun along with a probe. One of the participants was William Shatner, the actor who played Captain Kirk in the epic Star Trek. In total, more than 1.1 million people have sent requests to add their name to the nameplate to NASA.
“This is perhaps one of the most ambitious and extreme intelligence missions in human history. In addition, the spacecraft will carry as many names of people as they support the mission,”said program researcher Nicola Fox.
Nikolay Khizhnyak