In diesem Fall die Parker Solar Probe.

Zitat

---

On Christmas Eve, NASA's Parker Solar Probe will swoop within 3.8 million miles (6.1 million kilometers) of the sun's surface at a whopping 430,000 mph (690,000 kph), breaking its own records for speed and closest approach to our star.

The spacecraft, roughly the size of a small car, completed its final swing past Venus last month, setting it on a path to come closer to the sun than any human-made object ever has before.

On Dec. 24, the Parker Solar Probe is expected to cut through plumes of plasma that are still rooted to the sun and even fly through a patch of a solar eruption, akin to a surfer diving under a crashing wave. In October, the sun reached its most turbulent phase in its 11-year cycle, meaning the spacecraft will soon get to study powerful solar flares occurring on top of each other, providing scientists with up-close data about the chaotic workings of our star.

The probe's Christmas Eve feat is expected to occur at 6:40 a.m. EDT (1140 GMT), but mission control will be out of contact with the spacecraft at this time. Shortly before and after the closest approach — on Dec. 21 and Dec. 27 — scientists will look for a beacon tone from the probe that will confirm its health. If all goes to plan, the first images following the encounter may come as soon as the New Year kicks in, with science data following in the weeks after, said Rawafi.

During its upcoming closest approach to the sun, the front of the heat shield is expected to reach a sizzling 1,800 degrees Fahrenheit (982 degrees Celsius). That's pretty hot, but the mission team is confident the spacecraft and its instruments can handle temperatures up to 2,500 degrees F (1,371 degrees C)

---

https://www.space.com/the-universe/sun/w...m_medium=social

Loci classici der SF-Literatur über solche Nahbegegnungen:
Eric Frank Russell, "Jay Score" (Astounding Science Fiction, Mai 1941)
Arthur C. Clarke, "Thirty Seconds - Thirty Days" bzw. "Breaking Strain" (Thrilling Wonder Stories, Dezember 1949)
Arthur C. Clarke, "Summertime on Icarus" (Vogue, Juni 1960) (mit einer Entfernung von 17 Millionen Meilen, auf dem "Sungrazer"-Asteroiden des Titels, der als Schutzschild für die Raumfahrer dient)
und natürlich David Brins erster Roman, Sundiver (1980)

Zitat

---

The Sun appears as a hazard to spaceships that approach it too closely in some stories. In John W. Campbell's 1935 short story "Blindness", a scientist studies the Sun at close range in order to solve the mysteries of nuclear energy at great personal cost, only to find that the method for getting there was worth more than the discoveries made. Willy Ley's 1937 short story "At the Perihelion" involves a close approach to the Sun as part of an escape from Mars, and Charles L. Harness's 1949 novel The Paradox Men (a.k.a. Flight into Yesterday) is a space opera that climaxes with a swordfight atop a space station on the surface of the Sun. In Ray Bradbury's 1953 short story "The Golden Apples of the Sun", a crewed solar sample-return mission requires a spaceship to be cooled to near-absolute zero to endure the extreme heat during the critical phase. A fleet of near-Sun spacecraft that modulate the solar output for weather control purposes appears in Theodore L. Thomas's 1962 short story "The Weather Man". David Brin's 1980 novel Sundiver revolves around a hard science fiction journey into the Sun.

---

Sun in fiction - Close encounters

Und wo ich gerade darüber nachsinne: Herbert W. Franke, "Der Atem der Sonne" (zuerst in Franz Rottensteiners Anthologie "Phantastische Träume", Suhrkamp 1983 & 1986 ebendort als Titelgeschichte von Frankes 7. Erzählungssammlung) - wobei das dort geschilderte Rettungsmanöver & das Andocken an ein in naher Sonnenumlaufbahn gestrandetes Raumschiff einer Vorläufer-Expedition in diesen Gefilden (das sich als Büchse der Pandora erweist) ganz frappant an ein vergleichbares Szenario in Danny Boyles Film "Sunshine" von 2007 erinnert.

Willy Ley (unter dem Nom de Plume "Robert Willey"), "At the Perihelion" (1937):

Zitat

---

They did not fall in a straight line, of course; there are no straight lines in space. The orbit was a curve, the Sun being its focal point. This curve led from the orbit of Mars across the orbits of Earth and Venus. It crossed even the orbit of Mercury, approaching the Sun as near as only comets do occasionally.

At the point nearest to the Sun — the perihelion — the speed was highest; then it would diminish as it had increased, the rate of decrease being the same as the rate of increase. The curve would cross the orbits ofMercury and of Venus again. It would again cross the Earth’s orbit and approach that of Mars. But at the time the Earth’s orbit was reached again the planet would be near, and they would have to alter the direction of the flightby using the attraction of the Earth and the power of their rocket motors in most carefully calculated maneuvers.

This was Orbit Pirquet XIV C, simple in its elements, but risky beyond comprehension, because of its near approach to the Sun. It had never been tried before, but one of the first expeditions had completed a voyage using the very similar orbit, Pirquet XIV A, and had escaped.

As soon as the rocket motors had ceased firing, the ship had changed her appearance. She was a madly spinning double star now. On the one end of a thin but tough steel cable there was the main cabin, the supply room and the control room — in short, the upper part - of the vessel — on the other side the machinery and the fuel tanks. Held together by the three miles of cable, the two parts spun around each other, thus producing anartificial gravity in the cabin.
...
They passed the orbit of Mercury. The gigantic disk of the Sun seemed to fill the greatest part of the heaven: actually, it was less than a quarter of the sky. The three people in the ship were in their hammocks, stripped of their clothing, sweat standing in large drops all over their bodies. The curve of the flight still drew nearer to the Sun. The velocity was beyond imagination. It is easy to say that their speed had mounted to more than four hundred miles per second. The figure four hundred can only be comprehended as a figure. Four hundred miles per second are inconceivable. It is possible to conceive four hundred in thinking of four hundred people in a lecture hall, or of four hundred soldiers marching. It is even possible to conceive four hundred miles of distance. But four hundred miles per second is beyond conception.

It can be calculated — it can even be done, because it is within the realm of the natural laws — but it cannot be understood.

Then the velocity increased further.

The heat still increased further.

The ship seemed to stand still in space, except for its spinning.

The three in the ship believed that they felt pulsing waves of heat. Whenever the cabin part of the ship swung toward the Sun it seemed to grow hotter. But there was no feeling of a cooling effect when the cabin swung the other way.

They had sufficient water. The tricky little mechanism that extracted the moisture that was in the air of the cabin, cooled and condensed it, worked to perfection. But water, cold as it was, did not seem to help. It merely made the heat — by contrast — seem more embarrassing. They did not speak for hours at a time. Occasionally Dan forced Nadya to prepare some food. Afterward, when it was prepared, he had to force the
others and himself to swallow it. It was as if eating had become the hardest possible work.

Dan knew what every one of them thought. Are we going to fall into the Sun? His burning eyes forbade them to ask this question.

Seven days near the perihelion.

Now these seven days were actuality. Every one of them consisted of 86,400 seconds of unbearable heat.

“I thought I would die last hour,” said the professor suddenly. “But every hour brings a new and worse death — a death surpassing all the previous deaths taken together.”

“We cannot fall into the Sun,” Nadya voiced her thoughts. “Our velocity prevents it.”

“I cannot say where we are,” Dan answered the unspoken question. “I cannot make observations with all window shutters closed and the ship spinning as it is. But I do not dare to stop the rotation. Being toasted on both sides we may survive, being roasted on one we will not.”

THEY fell into silence again, for hours, for half a day. The heat grew, the pulsating waves of heat seemed to quicken.

Dan looked at the watch. “Dawn of the second day,” he announced, “prepare breakfast, Nadya.”

She did not answer; she did not even move.

---

Arthur C. Clarke, Astounding Days: A Science Fictional Autobiography (1990):

Zitat

---

Although Willy was a science-fact writer par excellence - the best in the business before Isaac Asimov - he did occasionally try his hand at fiction. The February 1937 Astounding contains "At the Perihelion" by "Robert Willey" - set on Mars in 1978. Alas, we never made it; not did Willy, who died in 1969 - just a few weeks before the first Apollo flight to the Moon.

Re-reading "At the Perihelion," I am impressed. I don't know what editorial help, if any, he had received, but Willy appears to have mastered English in a few years. (Though he spoke with a thick German accent to the end of his life, hence the "Villy" of all his friends.)

The story takes place on a realistic (for 1937) Mars, which is being colonized by the Soviets! Astounding's readers may well have been surprised to meet some sympathetic Russians, and Willy shows a nice sense of humour by bureaucratizing Mars with "light-years of red tape."

The most interesting point in the tale, however, is the technique used to cope with "weightlessness" on a long space journey: "As soon as the rocket motors had ceased firing, the ship had changed her appearance. She was a madly spinning double star by now..." Three miles! That seems excessive, and would involve a substantial mass of cable. To produce half normal Earth weight, the system would have to make one revolution very two minutes, which scarcely qualifies as "madly spinning."

But the principle is sound, and was tested in one of the Gemini missions. "Tethers" are now a Big Thing in space technology, and have applications Willy Ley could never have dreamed of in 1937. (Ch. 21, "At the Perihelion," S. 131)

---

"Pirquet" bezieht sich auf Guido von Pirquet (1880-1966), österreichischer Raumfahrtpionier, der einen der technischen Anhänge zu Willy Leys Anthologie "Die Möglichkeit der Weltraumfahrt" von (Hachmeister und Thal, Leipzig 1928 berechnet & verfaßt hat: "Die gangbaren Wege zur Realisierung der Weltraumfahrt" (S. 284-323). Der gesamte Text läßt sich hier nachlesen (auch für mathematisch Beschlagene ist das nichts für schwache Nerven). Die von Ley genannten Bahnen finden sich hier:

Zitat

---

Pirquet's early reputation was established when his conclusions were mentioned in the chapters written by Oberth, Hoefft, and Hohmann. Pirquet himself authored the chapter "Die ungangbaren Wege zur Realisierung der Weltraumfahrt," which was, of course, a very thankless task. ... Though counted at this time among the most famous rocket pioneers, nevertheless, Pirquet's most important and ingenious route was certainly the series of articles, entitled "Fahrtrouten" (routes for space travel) which he published in the journal "Die Rakete" between May 1928 and April 1929. Hailed as the most noteworthy of the year in astronautics, these articles deatl with the posisbility of realizing manned interplanetary flight. Two results are of special importance: First the route to Venus calculated by Pirquet was in fact followed by the first Russian rocket to Venus, launched on February 2, 1969.

Figure 2 shows the diagram of the route to Venus printed in "Pravda" (February 26, 1961); Figure 3, which is the diagram by Pirquet himself, contains his proposal of 1928.

---

(Fritz Sykora, "Guido von Parquet: Austrian Pioneer of Astronautics," in: Essays on the History of Rocketry and Astronautics: Proceedings of the Third Through the Sixth History Symposia of the International Academy of Astronautics, Volume I (NASA Conference Publication 2014); S. 140-154, hier S. 142-143.)

Die Berechnungen Pirquets für eine Flugbahn zum (und vom) Mars finden sich in den Ausgaben der "Rakete" vom September und Oktober 1928; Teil 2 auf den Seiten 134-137.

Einer der "klassischen" SF-Kurztexte, der in meiner Erzählung oben fehlt, ist Ray Bradburys "The Golden Apples of the Sun." Und im Zusammenhang mit der Parker Solar Probe finde ich dies hier:

Zitat

---

Alex Tolley mentioned Ray Bradbury’s story “The Golden Apples of the Sun” in connection with my first article on the Parker Solar Probe, and it’s a short tale worth remembering in connection with a mission flying so remarkably close to our star. First published in 1953 in a Doubleday collection of the same name, the tale is a short, mythic take on dangerous questing, with its main character, the unnamed captain, a figure something like Melville’s Captain Ahab. His goal is to fly to the Sun’s surface and retrieve some of its fire:

Zitat

---

The captain stared from the huge dark-lensed port, and there indeed was the sun, and to go to that sun and touch it and steal part of it forever away was his quiet and single idea. In this ship were combined the coolly delicate and the coldly practical. Through corridors of ice and milk-frost, ammoniated winter and storming snowflakes blew. Any spark from that vast hearth burning out there beyond the callous hull of this ship, any small fire-breath that might seep through would find winter, slumbering here like all the coldest hours of February.

---

The ship and crew, fighting malfunctioning equipment, fall in their cryogenic ship “like a snowflake into the lap of June, warm July, and the sweltering dog-mad days of August.” It’s Bradbury in full poetic mode, not one of his best tales but one that does capture a bit of the natural human awe at stellar immensity. As for the Parker Solar Probe and the European Space Agency’s Solar Orbiter mission, neither will ‘touch the Sun,’ though the former will close to about 6.2 million kilometers, with the Solar Orbiter at 42 million kilometers.

---

https://www.centauri-dreams.org/2017/06/...les-of-the-sun/

Astrophysikalisch ist Bradburys kleiner Text (die Geschichte umfaßt gute 7 Druckseiten) natürlich absoluter Humbug: das Schiff, mit Flüssiggasen auf den absoluten Nullpunkt gekühlt, fliegt bis in Reichweite der Sonnenoberfläche, fischt einen Batzen mit einer speziellen Thermoskanne heraus; Deckel zugeklappt und mit nach Hause genommen, um das als Zündfunken für heimische Reaktoren zu verwenden - Neuinszenierung des Raubs des Olympischen Feuers durch Prometheus. Bradbury hat sich nie die Bohne für technische Details oder tatsächliche Gegebenheiten interessiert; ihm ging es stets nur um die Symbolik. Insofern ist der Einwand, daß er das auch schon vor 70 Jahren besser hätte wissen können (genauer: seit 1920, als Arthur Eddington in "The Internal Constitution of the Stars" Wasserstofffusion als Quelle der Energieproduktion vorgeschlagen hat; Hans Bethge hat 1939 den Nachweis geliefert) verfehlt.

Was wir sehen, wenn wir die 🌞 ins Visier nehmen, ist die Oberfläche der Photosphäre, mit einer Temperatur von 5750°C (die Temperatur der Sonnenflecken liegt um 1000 Grad darunter, darum erscheinen sie dunkler), in der das Plasma dünn genug wird, um im optischen Bereich transparent zu werden. Die Dicke liegt bei 300 km. Darunter liegt die Konvektionszone mit einer Dicke von 200.000 km, in der die Energie, wie der Name sagt, durch Konvektion transportiert wird, mit einer Temperatur von 500.000°; darunter die Strahlungszone, in der das nur von Atom zu Atom über Quantensprünge weitergereicht wird, 300.000 km dick, 8 Millionen Grad heiß. Das ist der Grund, warum ein Photon im Durchschnitt 20 Millionen Jahre benötigt, um vom Kern bis zur Photokline, dem Übergang zur Konvektionsschicht, durchgereicht zu werden. In all diesen Zonen findet keine Fusion mehr statt (nur am unteren Rand der letzten - etwa 4% der Energieproduktion der Sonne). Das läuft - auf zwei verschiedenen Reaktionswegen - im zentralen Kern ab, mit einem Durchmesser von 150.000 km und einer Temperatur von 10 bis 20 Millionen Grad. Diese Temperatur darf um den Faktor 5 bis 10 unter der Betriebstemperatur eines Tokamaks liegen, weil dieser natürliche Fusionsreaktor groß genug dimensioniert ist, um genügend produzierte Neutronen zu absorbieren und eine Kettenreaktion in Gang zu halten.

Im Zusammenhang mit den Details zum Sonnenkern finde ich dies:

Zitat

---

The energy conversion per unit time (power) of fusion in the core varies with distance from the solar center. At the center of the Sun, fusion power is estimated by models to be about 276.5 watts/m3. Despite its intense temperature, the peak power generating density of the core overall is similar to an active compost heap, and is lower than the power density produced by the metabolism of an adult human. The Sun is much hotter than a compost heap due to the Sun's enormous volume and limited thermal conductivity.

---

https://en.wikipedia.org/wiki/Solar_core

"Der galaktische Misthaufen." Mal zum Vergleich: die Energiedichte im Prozessor eines modernen Smartphones beläuft sich auf 100 W/cm³, oder 100 Millionen Watt pro Kubikmeter. Mit anderen Worten: die Energiedichte eines Händis ist mehr als 350.000mal so hoch wie der innerste Bereich unseres Zentralgestirns. Es handelt sich da um die höchste Energiedichte, die im Universum vorkommt, mit der Ausnahme der Zündung einer Supernova.