Is the SpaceX Falcon Heavy payload (a Tesla car) space junk?



Yesterday SpaceX succeeded in the first Falcon Heavy launch, but the payload, a Tesla car has no real useful purpose (except for company prestige).

Thus, can it be considered as space junk ? How long will the car stay in orbit and has it been designed for an atmospheric disintegration? Is the car equipped with a propulsion system to change its trajectory in case of imminent collision risk ?


Posted 2018-02-07T12:33:48.697

Reputation: 498


Those answering may also wish to include that the Tesla included an Arch:

rrauenza 2018-02-07T17:26:18.240

2Based on the answers you've gotten, this largely depends on the definition of "Space Junk" that you're using - it might help to indicate what definition you are using, so that answers can be written accordingly.Zibbobz 2018-02-07T17:48:41.450


There's no legal definition for space junk. The 2010 UN Space Debris Mitigation Guidelines define space debris as “all man-made objects, including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional.” Since the Falcon Heavy payload is not in Earth orbit, it is not space debris as defined in that document. But there are other definitions. Consider rephrasing the question in a way that can be answered, not just argued over.

David Moles 2018-02-07T18:05:00.030

9Shouldn't this be closed as opinion-based? It looks like we're just arguing about the definition of "junk" here.user2357112 2018-02-07T21:14:06.257

@SF. Of course, the trouble with large debris (though not as much with the Tesla due to where it is) is that it becomes a source of small debris through various collisions with uncontrolled small debris and material degradation over time.Tristan 2018-02-08T15:17:08.880

2@user2357112: Competent answers will provide and support a definition of "junk" that does not rely on opinions. The top-voted answer, for example, relies on fairly straightforward arguing from NASA standards and known statistics. So it's not POB, as there's something other than opinions to appeal to.Nathan Tuggy 2018-02-10T19:54:17.610

I think, the close reasons should be interpreted on a narrow way, particularly in the case of such popular questions. This question can have a non-opinionated answer, roughly this: "yes, it is, but it is not a dangerous or problematic one". From the other side, nobody likes bikesched posts, and it is a bikesched one, but I think, considering its popularity, it is better to tolerate it. So, I suggest "leave open".peterh 2018-02-11T14:06:32.903

Interesting how the answers mostly deal with the definition of junk. Beyond that the facts seem to be quite clear. The real answer is that it's simply a matter of definition. The question is not clear enough and should clarify what it means by "space junk"? Otherwise the question is nearly unanswerable. The two highest voted answers seem to say the exact opposite for example.Trilarion 2018-02-12T08:09:04.373

1@user2357112 Not opinion-based because once the definitions are clear, a clear answer is possible. It's the responsibility of the question to provide all relevant definitions, otherwise it's unclear.Trilarion 2018-02-12T08:19:50.520

@Trilarion Simply replicating the definitions of well-known things is an irreal expectation. And "space junk" is a well-defined thing (or, it should be).peterh 2018-02-17T21:20:57.870

@peterh Sometimes things regarded as well-defined aren't. Have you looked at the answers? They all kind of disagree what space junk is. And why should the term by actually well-defined? After all it's nothing we have to deal with in our everyday lifes. Space junk hardly mattered so far, therefore it's not surprising there is no consense on the meaning. I'm not surprised.Trilarion 2018-02-19T13:46:15.260

@Trilarion It is right, but I think it doesn't make the question unclear. The answers make clear, that the answer depends on, how we define space junk. I think, not closing this question, is a little step into a far future, where interplanetary space junk may be a problem. And I want this future.peterh 2018-02-19T14:08:15.043

@peterh Closing a question may not be the end. It gives the questioner time to improve it and get it reopened. What we have now is voting according to the favorite definition of space junk of the voters, at least partly. This part is not giving us much useful information, or does it? I mean, how is this question helping to highlight that interplanetary space junk may be a problem? I'm tempted to edit the question and add a definition of space junk but I'm afraid then the answer would be a trivial yes or no. Maybe the question wanted to ask what space junk is actually?Trilarion 2018-02-19T14:20:32.327

@Trilarion The question is a bikeshed question and I in general dislike to read the meaningless terminology-lawyerism. In this specific case, considering the view count and the popularity of the question, I think the broader context (popularization of space exploration, particularly in the U.S.) dictates an exception. This was my reason to vote for leave open. I think your reason of being here dictate some similar.

peterh 2018-02-19T15:10:07.250



No, because it is not in Earth orbit

First the payload does have a purpose: it is a boilerplate, and those have a purpose, namely to "test various configurations and basic size, load, and handling characteristics of rocket launch vehicles".

Second, you are asking...

is the car equipped with a propulsion system to change its trajectory in case of imminent collision risk ?

No, it is not. The payload is not in Earth orbit any more. It is in an elliptical heliocentric orbit. The likelihood that is will ever be a collision risk for anyone or anything is infinitesimal.

Generally — as this NASA page states — we only consider objects in Earth orbit to possibly be space junk, or "orbital debris" as the more technical term for such things are.

1). What are orbital debris?

Orbital debris are all man-made objects in orbit about the Earth which no longer serve a useful purpose.

The reason only objects in Earth orbit are considered "orbital debris" is because only those are of relevance to us. We do not expect to ever run into man-made objects that are not in Earth orbit, simply because the probability of a collision is so small and the number of them is so low, that combined it is not worth the effort to try to prevent any such collisions. By comparison we do not even try to protect against meteor/meteorite strikes even though the Earth is hit by such — the size of the Roadster or larger — several times each year. If that does not bother us enough to warrant taking measures to prevent it from happening, why would the Roadster warrant it? It simply does not.

If you personally want to call the Roadster "space junk" you may do that of course, but I will counter that by saying "Yeah but it is harmless space junk".


Posted 2018-02-07T12:33:48.697

Reputation: 1 486

5The number of rocks of equivalent size that orbits the Sun could not be estimated, about 65000 objects within the asteroid belt are known. But rocks of the size of a car could not be detected from Earth.Uwe 2018-02-07T13:36:15.413

even if the definition of space junk went beyond earth's orbit, rocks wouldnt fit the definition as they are not man-madeMart10 2018-02-07T14:12:26.437

8Space junk is anything that we put up there that we're not using, regardless of whether it's in earth orbit.Tristan 2018-02-07T14:39:35.827

50@Tristan According to... who?MichaelK 2018-02-07T14:44:15.807

Wikipedia is hardly a reliable Source. Imho, location is irrelevant for space junk. What is important is that it was an artificial object, and that it no longer serves its purpose (which would include dead satellites that aliens have put up around their world, there is no reason we should not consider those as space junk just because they do not orbit Earth). just because as of now, there did not exist any space junk outside of LEO does not mean there never will.Polygnome 2018-02-07T15:38:26.320

9The location matters. We worry about junk in Earth orbit because there's a much higher (relative) chance of hitting it, as opposed to junk orbiting the sun (a MUCH larger obit)Alexander 2018-02-07T23:45:00.090

@MichaelK Junk: Old or discarded articles that are considered useless or of little value. Space Junk: Junk in space.SBoss 2018-02-08T14:00:14.060

1@SBoss By that same reasoning all the equipment at the Apollo landing sites are now "junk" (with the exception of the retro-reflectors). but still people are fussing about those sites so much that they are hesitant to let even small remotely controlled rovers land anywhere near them for risk of fouling the sites.MichaelK 2018-02-08T14:05:24.900


@MichaelK The term of art is really "Orbital Debris." "Space Junk" is an informal colloquialism. That definition is according to (among others) NASA's Orbital Debris Program Office (see, as well as the various teams of engineers (myself included) who actually work on mitigation and spacecraft survivability with respect to meteoroid and orbital debris impacts.

Tristan 2018-02-08T15:00:38.073

7@Tristan Thank you. Point 1 on that page (emphasis mine): 1). What are orbital debris? Orbital debris are all man-made objects in orbit about the Earth which no longer serve a useful purpose.".MichaelK 2018-02-08T15:20:58.937

3@MichaelK That distinction is due to the ODPO's raison d'être, which is to track and model debris in orbit around the earth. When interplanetary missions become common enough that solar-orbit man-made objects pose a non-negligible threat to mission success, their scope will expand accordingly. In practical terms, for earth-orbit spacecraft, the distinction between (earth) orbital debris and meteoroids is in the encounter velocity (~11 km/s typical for debris, ~25 km/s typical for meteoroids.) Put simply enough, if it's non-functional, it's junk, and if it's in space, it's space junk.Tristan 2018-02-08T15:27:07.367

1@MichaelK some parts on the Apollo landing sites might be junk, (i.e. a potential fallen off lever or similar) some parts (the larger ones as the serve a purpose: They mark a historic site and event and act as a monument) If a random car from some random launch (it's not the first launch ever or such which might make it relevant, also not the first thing leaving our orbit, but likely to be forgotten on historic scale) serves such a monumental value can be argued (I doubt it and for me it's junk, which served it's purpose and now doesn't matter anymore)johannes 2018-02-08T16:01:14.827

2${$Orbital debris$}\subset{$Space junk$}$: All orbital debris is space junk. Some space junk isn't orbital debris. The question is "is it space junk?" It was not "is it orbital debris?"Tristan 2018-02-09T14:55:36.827

3@Tristan OP is clearly talking about stuff that presents a tangible hazard to humans and/or human space operations. The Roadster does not qualify for that. The likelihood of it ever presenting a hazard is infinitesimal. Sure... with incredible bad luck, it will park itself on someone's driveway in a few thousand years, and with that disintegrate the driveway (and the house, and most of the neighbourhood). But no-one is bothering about that risk at all. The issue at hand was not the wording but if it is a hazard.MichaelK 2018-02-09T15:43:22.237


Yes, it's space junk: after about 6 hours, the second stage will stop working and there will be no way to change the trajectory of stage and payload. So it's a non-functional satellite, i.e. junk. An object whose course cannot be controlled, and a potential future navigation hazard.

It's not in Earth orbit, so it's unlikely to cause a problem here. There is no propulsion system that will work after about 6 hours, and no sensors to detect an imminent collision.

If it reenters at some point (because its orbit intersects that of Earth), reentry will be fast enough that it'll burn up. If it entered Mars' atmosphere, it might survive reentry and crash on the surface.


Posted 2018-02-07T12:33:48.697

Reputation: 63 604

33In this context "junk" seems to be a technical term-of-art, not perjorative per se.davidbak 2018-02-07T15:08:53.997

11Are you sure Mars has enough atmosphere to burn the Tesla before lithobraking kicks in?gerrit 2018-02-07T16:57:19.950

7"So it's a non-functional satellite" Is it non-functional? Sure it has no means of propulsion, but it was never designed to. Instead, it was designed to fly around for an indefinite period of time as a testament to Tesla, SpaceX, and Sci-fi culture... or in simple terms Art. Could this not be considered a function?NPSF3000 2018-02-08T03:39:08.667

3It can be noted that a car is much safer than a block of concrete in case of reentry. Aerodinamic as it may be, it will be torn appart and burn.Madlozoz 2018-02-08T08:48:00.677

6The car also has a data payload, containing works of art and culture. Therefore I don't think it should be considered "junk". Will the Voyager probes be considered "Junk" once their power source decays beyond use? They contain plaques which were designed to be read by extra-terrestrial species, so it doesn't require power. The Tesla data-payload can be considered the sameJLo 2018-02-08T16:53:48.827

Its function was public relations. Now that transmissions have ceased, it's fulfilled that function. As an advertisement it was successful (witness the pile of questions it's generated here), but that's not enough to make it art.Hobbes 2018-02-08T16:55:02.150

2@Hobbes Really? Why not? I agree that it's at least partly an advertisement, but that doesn't mean it's not art. I think the fact that it has inspired a great deal of curiosity is one of the strongest arguments for its artfulness.Harabeck 2018-02-08T22:49:22.583

@davidbak "In this context "junk" seems to be a technical term-of-art, not perjorative per se." Not sure. Junk implies uselessness. One could probably have equipped the rocket with something more useful than a Tesla, a satellite doing a scientific mission instead maybe. In that sense using a Tesla instead and denoting it as junk could be seen as a pejorative judgement, I would say.Trilarion 2018-02-12T08:13:34.973



${}^1$ That the term "Space Junk" (as used in this answer and which is probably the right answer) has a different generally agreed meaning in spacecraft lingo than just plain "Junk" has been pointed out in this answer as well as in in this comment.


1. It is Space Art.

It started as visual art (we watched it on YouTube, it was beautiful! (makeshift GIF, looking for something better)).

And now, it will forever be conceptual art. Even the Wheel of Cheese was art.

Tongue in Cheek from The Verge: Elon Musk made history launching a car into space. Did he make art too? - An investigation, with a very official point system

2. It is not "junk${}^1$".

Will Voyagers, with their plaques and records that Carl Sagan and a host of others word so hard to make happen be simply "space junk" when we loose contact? Will New Horizons, carrying Clyde Tombaugh's ashes and artifacts be junk as well? Are you sure? Perhaps consider the points made in this answer. "One person's junk is another person's treasure..."

The Pioneer Plaque, junk as well? Or is there in fact still a purpose to these spacecraft's existence?

The spacecraft also serves as a symbol. It has a purpose, people will visit it again in the future if it hasn't collided with something, there's absolutely no question about that. There are already plans to revisit the Apollo landing sites.

It is a statement, a symbol, an artifact. It's more than discarded rocket body number n, it's a red sports car in space!


Posted 2018-02-07T12:33:48.697

Reputation: 19 082

Got a source with that?Mast 2018-02-07T13:27:28.300


@Mast I know it when I see it and this is art :-)

uhoh 2018-02-07T13:31:45.830

16Being art does not exclude it from being junk. 2018-02-07T14:51:23.520

3Art is very subjective. And still, it can be both.Polygnome 2018-02-07T15:18:57.220

1Plus, I consider things like the Apollo 12 S-IVB space junk, but still also consider it of great historical importance and of cultural value. One does not necessarily exclude the other. Junk is "old or discarded articles that are considered useless or of little value." Note the "or". The car is certainly discarded and useless, as is the aforementioned S-IVB. Which is enough to qualify it as junk, it does not have to also fulfill the condition of being value-less.Polygnome 2018-02-07T15:21:25.747

@Polygnome I haven't enforced exclusivity. However as thrust delivery systems, those rocket bodies have, without question, been discarded, as have esentially every single rocket body before (some of) the recent F9's. They have literally been "thrown away". Most tossed into the sea, others into space. They may have historical significance, but they have been discarded none-the-less. However, the spacecraft I've mentioned have been intentionally and explicitly used for other purposes beyond propulsion. Junk doesn't get a plaque, or get strapped in with a seatbelt.uhoh 2018-02-07T15:25:09.180

@uhoh I don't follow, why would the presence of i.e. the Golden Record (which could very well be viewed as art) mean the Voyager probe is not space junk once it stops working? Remember that those probes were never intended to leave the solar system in the first place, and when they stop having power they stop serving any practical purpose, only merely have a symbolic / philosophical value.Polygnome 2018-02-07T15:41:32.190

@Polygnome we disagree on many of the statements you've just made about intents and purposes. I think it would be a great idea to explore this further in a new question. It's late here though, so I'm signing off for today...uhoh 2018-02-07T15:47:21.353

Art is anything worth more than its scrap value.Mazura 2018-02-07T23:04:56.150

You may think it is art but that does not make it not space junk, which it isAnton 2018-02-08T17:31:55.420


It depends.

In the industry, the concern with space junk is whether or not certain objects are a navigational hazard. If the Falcon Heavy payload were on a collision course with an active spacecraft, then it would definitely be a navigational hazard, as it has no way to redirect itself. That said, there really isn't a lot to avoid out where it is going.

As can be seen in the other answers, the issue of whether or not the payload can be considered "defunct" is more subjective, and in fact it is an issue that is unlikely to be resolved by some formal definition. Space junk is loosely defined for a reason. We talk about it from a collective perspective. Individual items simply aren't relevant until they are an active threat. That isn't to say that individual items aren't tracked--they are. That is part of the mitigation strategy for the broader issue.


Posted 2018-02-07T12:33:48.697

Reputation: 13 142


If you define "space junk" as any human artifact anywhere in space serving no useful purpose, then Starman has become space junk, but so have a number of NASA or other space agency probes that have either malfunctioned, or exhausted their propellants and/or power supplies (RTGs), so the Voyagers are destined to become "space junk" in interstellar space.

If you define "space junk" as a synonym for "orbital debris" (human artifacts in Earth orbit serving no useful purpose, as is usually the case), then no, Starman is not because it is not in Earth orbit.

Junk in space only matters if

  • It has the potential to collide with or crash down upon something that matters to you
  • It could introduce some form of contamination into a target of scientific study e.g. microbes on Mars.

Orbital debris matters because there is so much of it.

Anthony X

Posted 2018-02-07T12:33:48.697

Reputation: 7 976


It's still transmitting imagery, so by that standard it's not junk (yet). Once the batteries drain it will be inert. It has no propulsion capability to speak of, not even reaction control thrusters to change attitude.

It's on an orbit where aphelion will be in the asteroid belt; the odds of it posing a hazard to future space flight is low. If, in the coming years, it encounters Earth and re-enters, it will burn up fairly easily.

It's less of a hazard than dead sats and debris in MEO.

John Bode

Posted 2018-02-07T12:33:48.697

Reputation: 989

8No, it is no longer transmitting imagery.called2voyage 2018-02-07T20:41:11.683

3The transmissions stopped after four hours.called2voyage 2018-02-07T21:05:47.150

2It won’t reach the asteroid belt eitherTim 2018-02-09T18:53:45.323