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I've seen a lot of questions about the $\Delta V$ required to reach the Sun from the Earth (~22-30 km/s if I remember correctly), firing a bullet into the sun, etc.

But has this ever happened? Has any object launched into space from Earth deliberately or accidentally gone into the sun and never come out? I.e. being engulfed by a solar flare and surviving doesn't count. The expectation is that the object would keep falling deeper into the sun until it disintegrated.

peterh
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CJ Dennis
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    "Has any object launched into space from Earth ... gone into the sun and never come out?" Could anything (except photons) go into the Sun and then come out? – RonJohn Sep 09 '19 at 18:48
  • @Ron - I kind of thought the same thing... How does something return from the sun? It has to be a one-way trip. For example, some of the debris from space junk and some of the debris from the Chinese blowing up that satellite have surely made it to the sun due to gravitational forces. How does the debris come back out? – jww Sep 09 '19 at 20:08
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    @RonJohn I've submitted an edit to remove the word "permanently" from the title, since it accomplishes nothing but confusing people who read it. – Monty Harder Sep 09 '19 at 21:46
  • Afaik it is $\approx 41$ km/s. 13km/s to leave the Earth, 28 km/s to neutralize its orbital speed around the Sun. It is absolutely impossible with the todays technology. A very complex trajectory, like the Parker Solar Probe, using many gravitational slingshots, could get into the Sun in $\approx$ a decade. – peterh Sep 09 '19 at 21:59
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    @peterh If you just want to drop something into the sun, starting from earth you need about 21.78km/s. See e.g. here: https://space.stackexchange.com/questions/38604/what-is-the-delta-v-required-to-get-a-mass-in-earth-orbit-into-the-sun-using-a-s/38605#comment123648_38605 – Polygnome Sep 09 '19 at 22:53
  • @MontyHarder The edit is bad, because now the title and the question body no longer match. The question body asks about an object being launched permanently into the sun, and my answer perfectly matched the old title and body. now the title doesn't fit the opening sentence of my answer anymore. Its a meaning in change that I think wasn't intended by the OP. I'm not going to start an edit war about it, but I think this was a bad change. – Polygnome Sep 09 '19 at 22:56
  • @Polygnome I don't see how it doesn't fit your answer, but I definitely see your point about the wording in the body. I still think the original title was very distracting, and the comments getting hung up on it reinforce that. I'm not sure what the best way is to get rid of the distraction. – Monty Harder Sep 09 '19 at 23:07
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    @MontyHarder "the title [... confuses] people" [citation needed]. I put the word "permanently" in the title to prevent language lawyers from claiming objects like MESSENGER or Mariner 10 have been in the sun. – CJ Dennis Sep 09 '19 at 23:18
  • @RonJohn : Photons (as you mention), neutrinos, gravitons, black holes, neutron stars, the second member of a train of super-relativistic moons, comet Lovejoy (although, admittedly, one should decide whether entering and exiting the corona counts as "going into the sun") and other large enough sungrazers. – Eric Towers Sep 09 '19 at 23:52
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    @EricTowers good point on neutrinos. Would a black hole go into the Sun, or would the Sun go into the BH? Ditto neutron stars? – RonJohn Sep 09 '19 at 23:55
  • @RonJohn : In the Solar CoM coordinate system (which I use for all my fussy time calculations), ... – Eric Towers Sep 09 '19 at 23:57
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    @EricTowers I don't understand that comment. – RonJohn Sep 10 '19 at 00:01
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    @RonJohn : If our coordinate system is anchored to the center of mass of the Sun, then other things fall into the Sun (since the Sun is always stationary in that coordinate system). TDB is an atomic timekeeping system that is based on a hypothetical atomic clock sitting at the CoM of the Solar system (which I usually don't bother to distinguish from the Sun's CoM since the distance between them is usually $\leq$ a few hundred kilometers and the difference in redshifts between the two is small). – Eric Towers Sep 10 '19 at 00:10
  • Define "into the sun". If it gets vaporized before it touches the actual surface, does that count? If it doesn't, I suspect we wouldn't be able to shoot something into the sun even if we wanted to. – Flater Sep 10 '19 at 12:39
  • Obligatory XKCD: https://xkcd.com/1830/ – AAM111 Sep 10 '19 at 13:49
  • @CJDennis the first two comments were about the "permanently", missing the point you seemed to be trying to make about a solar flare not really being "the Sun" itself, so passing through one isn't "going into the Sun". – Monty Harder Sep 11 '19 at 14:23
  • @CJDennis per this FAQ you won't receive a notification of my comment because your edit was rejected or pending, so I'm leaving one here. Feel free to leave a comment or an answer at the meta question linked there. – uhoh Sep 21 '19 at 07:58

2 Answers2

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No, not yet. The Parker Solar Probe became the closest ever artificial object to the sun on October 29th, 2018, surpassing Helios 2 which held the record since 1975 [1].

No other human-made object has been closer to the Sun. The probe will repeatedly touch the outer corona until mission end in 2025, with the closest approach being 3.83 million miles [2]. It will then lose altitude [sic] control and will end up as debris field around the sun, while parts of it may fall into the sun in the next few billion years [3].

The spacecraft reached the low perihelion by repeated gravity assists from Venus.

References:

  1. https://en.wikipedia.org/wiki/Parker_Solar_Probe
  2. http://parkersolarprobe.jhuapl.edu/The-Mission/index.php
  3. https://www.telegraph.co.uk/science/2018/08/09/nasa-probe-will-still-circling-sun-end-solar-system-say-scientists/
Polygnome
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    "It will then lose altitude (sic) control..." needs a source, there might be a possible mission extension unless you're sure that that's scheduled and inevitable. – uhoh Sep 09 '19 at 08:16
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    @uhoh I've included a link to an interview with the program manager of the parker solar probe as reference for that. – Polygnome Sep 09 '19 at 08:21
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    I'm pretty sure "altitude" should be "attitude" in that article. – JohannesD Sep 09 '19 at 16:46
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    Once it runs out of propellant and/or its reaction wheels fail loss of attitude control is inevitable. Components hiding behind the sun shield will get slagged down when exposed to direct solar radiation; but anything burned off I'd expect to be blown away in the solar wind. To fall into the sun, drag during its passes through the Corona would need to be sufficient to de-orbit the remnant. Is drag actually strong enough to accomplish that it was the interviewee speaking figuratively? – Dan Is Fiddling By Firelight Sep 09 '19 at 17:53
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    @DanNeely I think drag is not enough for that. It will be still $\approx$ 3 solar diameter away, and the solar atmospheric density decreases exponentially. After the loss of attitude control, the probe will quickly die, later starts to rotate. Probably its tungsten shield will last the longest, it is hard to calculate, when will it fully evaporate. Possible, that it is will survive until billions of years (note, it will heat only until $\approx$ 2000C, and tungsten melts at 3400C). – peterh Sep 09 '19 at 22:03
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    @DanNeely The article of the telegraph suggests that most of the probe will end up as a debris field around the sun, and only parts of it will fall in (and only over a very, very long time). – Polygnome Sep 10 '19 at 06:45
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It is not possible for a probe to go accidentaly into the sun, the necessary delta v could not be reached by accident. A two stage rocket is needed for an Earth orbit, about 8 km/s delta v. About 22 km/s for an Earth to Sun trajectory would require about 5 to 6 stages with a delta v of 4 km/s per stage. Such a rocket was never build.

Uwe
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  • "It is not possible" seems a bit strong - we're not talking about breaching light-speed or anything like that! – MikeB Jul 18 '23 at 15:53
  • @MikeB Nobody will build and launch a five stage rocket accidentally. – Uwe Jul 19 '23 at 12:22