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Inspired by this news item Boeing-made satellite breaks up in space, which in part states:

A communications satellite designed and built by embattled aerospace giant Boeing has broken up in orbit.

The satellite's operator, Intelsat, has confirmed the "total loss" of iS-33e

and

the US Space Forces also said it is "currently tracking around 20 associated pieces" of the satellite

Is it simply a case of poor manufacturing & a lack of quality control concerning the manufacturing of the satellite, or did the satellite have a "very rough" release and subsequent orbit insertion?

P.S. The satellite subject to disassembly is Intelsat 33e, launched 2016-08-24, i.e. some time ago, which is not made clear at all in the BBC article.

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    $\begingroup$I would think of a collision with a small debris object in an orbit unfortunately on a collision course$\endgroup$
    – Uwe
    CommentedOct 23, 2024 at 10:28
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    $\begingroup$Note that IS-33e already had a reduced lifespan due to two separate problems with its propulsion systems. Given that the propulsion systems are also the main "explodey" bits on a satellite, that could also be an explanation. But we might never know, considering Intelsat is a private company and is not required to disclose mishap investigations.$\endgroup$
    – Jörg W Mittag
    CommentedOct 23, 2024 at 12:29
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    $\begingroup$Not an answer yet, but TASS has a relevant Russian expert saying that it was a fuel tank explosion tass.com/science/1859913, but suspect that is based on the fact that they did not track a debris strike event and if there is an explosion it pretty much has to be fuel.$\endgroup$
    – GremlinWranger
    CommentedOct 23, 2024 at 13:00
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    $\begingroup$As is almost always the case with serious space incidents, and especially incidents involving rapid unplanned disassembly, this question is unanswerable this soon after the incident. It might well be unanswerable forever. For example, the root cause of Intelsat 29-e remains unknown, either a micrometeoroid impact or an electrical short possibly caused by faulty wiring or high solar activity. This happened over five years ago, and they still don't know the root cause. Asking about something that happened just a few days ago is premature.$\endgroup$
    – David Hammen
    CommentedOct 23, 2024 at 15:17
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    $\begingroup$@DavidHammen I disagree; asking about something while it's on your mind is perfectly understandable. It doesn't mean an answer is expected right now.$\endgroup$
    – Erin Anne
    CommentedOct 23, 2024 at 17:37

2 Answers 2

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How does a modern day satellite fall apart in space?

This generic question is answerable. They blow up, aka rapid unplanned disassembly (RUD) but due to a large number of causes. Or parts fail slowly and the vehicle eventually loses structural integrity. There are lots and lots of things that can go wrong on objects in space. They are not designed to live forever because space is a rather hostile place and also because the future will bring even better devices. Planned obsolescence.

The specifics about the loss of Intelsat 33e (iS-33e for short) is not yet known, and the root cause might never be known. It's rather obvious that iS-33e suffered RUD. There are now over 80 observed pieces of debris from this event. That is without a doubt a sign of an explosion. But what caused it? Root causes can be very difficult to chase down, and if the root cause is knowable, it typically takes months to years to root them out.

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    $\begingroup$Is a collision with space debris likely ruled out by the amount of fragments or by their approximate size distribution (about equal in size) - or what makes the explosion the most likely explanation?$\endgroup$
    – planetmaker
    CommentedOct 23, 2024 at 22:16
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    $\begingroup$@planetmaker A collision with even a bullet-sized object (or even smaller) can trigger lots of damage that can eventually cascade into a propellant tank explosion or battery explosion if the bullet-sized object (or even smaller) was moving much faster than a speeding bullet. Micrometeoroids typically make speeding bullets look like snails in comparison. Cascading faults are hard to diagnose. This was obviously an explosion of some sort. Root cause? Who knows. A micrometeoroid collision cannot be ruled out as the root cause.$\endgroup$
    – David Hammen
    CommentedOct 23, 2024 at 22:24
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    $\begingroup$@Fred You have two questions in your question. One, the title, is answerable, but is a bit of a list question. The specific question, what happened to iS-33e, is not answerable, at least for now.$\endgroup$
    – David Hammen
    CommentedOct 24, 2024 at 8:03
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    $\begingroup$I wonder how many NTSB investigators would be chomping at the bit for a free ride to space.$\endgroup$
    – Barmar
    CommentedOct 24, 2024 at 14:55
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    $\begingroup$@Barmar That depends on whether the free ride is provided by Boeing...$\endgroup$
    – Mark Morgan Lloyd
    CommentedOct 24, 2024 at 19:22
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There's no way to know what went wrong with this particular satellite, so I'll answer the generic question instead: what could blow up in a satellite?

First, a satellite needs to get to orbit. For a geostationary satellite like Intelsat this usually means it is boosted to a lower orbit by a rocket, then the rocket runs out of fuel and the satellite separates and lifts to the final orbit using its own rocket engine. The satellite itself is the last stage of the rocket, which saves weight.

The rocket engine remains onboard, with propellant reserves, which will be used at end of life to deorbit it or put it into a graveyard orbit.

Then it needs to adjust its attitude to remain pointed in the right direction. To do this it can use:

  • Cold gas thrusters, which require high pressure gas tanks
  • Hot thrusters, which require tanks of rocket propellant(s)
  • Flywheels, which usually store enough kinetic energy to explode if the bearings jam.

It also needs a rather large battery to keep working when it is in the shadow of the Earth.

So there's no shortage of stuff that can blow up.

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    $\begingroup$There are couple of things that are wrong here. (1) The upper stage of the rocket that launches the satellite into space places the satellite in a geostationary transfer orbit. The upper stage and satellite eventually detach, with the upper stage reentering the atmosphere and the satellite itself circularizing its orbit at apogee. (2) A large number of vehicles in GEO currently use ion thrusters. Some use xenon as the propellant, but others do use hydrazine, which is a rather nasty substance.$\endgroup$
    – David Hammen
    CommentedOct 24, 2024 at 11:45
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    $\begingroup$@DavidHammen: I don't know about Ariane 5, but neither Falcon 9 nor Falcon Heavy have enough performance to perform a deorbit burn of the second stage after delivering a huge geostationary communications satellite to GTO. They boost into a graveyard orbit instead. I find it unlikely that Ariane 5 could do that, for the simple reason that it would be a waste of propellant: it would make a lot more sense to use that extra performance to save propellant on the satellite rather than use it to deorbit the second stage.$\endgroup$
    – Jörg W Mittag
    CommentedOct 24, 2024 at 12:07
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    $\begingroup$@JörgWMittag I would think that boosting into a graveyard from a GTO would cost more in terms of delta-V than would be a slight nudge at apogee (roughly geostationary altitude) to send the upper stage into the lower atmosphere at perigee. But I could be wrong. Multiple articles say that I am not wrong, but lay media oftentimes get it wrong.$\endgroup$
    – David Hammen
    CommentedOct 24, 2024 at 14:40
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    $\begingroup$@JörgWMittag Jonathan McDowell's catalog is a good but not great source. It has numerous errors.$\endgroup$
    – David Hammen
    CommentedOct 24, 2024 at 14:41
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    $\begingroup$Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.$\endgroup$
    – CommunityBot
    CommentedOct 24, 2024 at 15:06

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