The "Piece of MIR" that quite probably isn't
MIR was a Russian Space Station, in many ways the fore-runner of the ISS, which was de-orbited in March 2001.
While the story was quickly and uncritically proliferated by several news outlets (even RIA Novosti), many space and satellite buffs (including this blog's author) were suspicious of the claims right away. The object, a glassy piece of rock, looked nothing like a genuine piece of space debris. And the specific link to MIR or a MIR-era Russian spacecraft seemed dubious in the absence of a recognizable machine part morphology or machine part registration number.
Here are a couple of pictures of the object, which are screenshots from the CBS Boston video news report here:
The man who reportedly found it, claims he picked it up from the mud at low tide several years ago at a point where his backyard touches on the banks of the Merrimack river. It was a greenish glassy rock "covered in mud".
He put it under a tree in his yard where it sat for several years until his sister in law, who knew someone at NASA, sent it to that person for analysis. Or so the story goes. Many months later, the object was returned with a letter purporting to be from a NASA engineer called "George Leussis". In this letter it was identified as "a piece of MIR" or ballast from a MIR-era Russian spacecraft.
But is it? To be frank: most likely it is not.
First of all, while ballast is sometimes indeed added to space launches (to let the launch mass match the rocket performance), this is not in the form of rock. Such ballast is usually water (in a tank), sand, or metal. And glass is not a major component of spacecraft (glass fiber is though). Certainly not in seizable chunks.
More important than that: what are the reasons to think this is space debris in the first place? It doesn't look like a part of a spacecraft at all. It looks like a glassy rock.
The piece looks like a silicate glass, with clear signs of weathering (e.g. the pitting on the surface, the dull glossy shine), and clear conchoidal flaking (best seen on the third picture above). Contrary to the impression given by the news reports, I can see no evidence of a "fiery entry through the atmosphere" on the pictures of the piece. It looks like a smelt alright, but contrary to what many people think that is not what you get from an atmospheric reentry. Pieces will ablate and will get a thin fusion crust (thin melt layer) just like meteorites, but they do not melt completely and next solidify into a clump again.
The conchoidal fracturing certainly would have to have taken place after any melting, and given that the flaked surface has the same green-brown colour there, the latter colour is certainly not due to any superficial burning.
To be honest the object looks very much like either one of two things (which can look quite alike on photographs, since both are silicate melts):
1) a piece of obsidian (volcanic glass);
2) a piece of industrial silicate slag.
The first is a natural material: the second is man-made waste. Both basically consist of solidified clumps of glass and often have a dark blackish, greyish, brownish or greenish colour. They can show flow lines in the glass, vesicles, and are subject to weathering phenomena that include surface pitting from dissolution. All of which can be seen on the pictures of the object in question.
So what actually traces this clump of silicate melt to the Russian space program rather than a more earthly origin? The short answer: apparently nothing.
A molten silicate is not unique to products of the Russian space program. In fact it is not likely to be a product of any space program. It is very ubiquitous on earth as industrial waste, as volcanic product etcetera. Only if a geologist can ascertain the object is none of those, then one can think of another, more wilder and rare origin - such as Russian space "ballast". Note that none of the news stories mentions a geologist looking at the object - they only mention a NASA engineer (but: see below!).
The next claim in the story is the specific link to the Russian space program (rather than space debris in general) - Mir or Progress. In the absence of a recognizable morphology or a machine part number, this link is completely uncorroborated.
At the least, I would like to see a clear chemical analysis with an argument why the composition would uniquely point to the Russian space program, as opposed to a common terrestrial origin (i.e. an industrial slag or a volcanic glass).
The letter quoted in one of the news articles claims such, but in vague and ambiguous wording. It seems to say the material is terrestrial, and only the "green colour and strange properties" according to the letter point to it having been "subjected to a fall from low Earth orbit". The green colour is however certainly not unusual for industrial silicate slag and volcanic glass, and I see no "strange properties" in the published images of the rock nor the descriptions of the rock that would point to it having experienced an atmospheric entry (or would be unusual for an industrial silicate slag or volcanic glass). Moreover: the apparent "letter from NASA" has since come under suspicion.
For here is the clincher: it is claimed that the identification was made by a NASA engineer called George Luessis. An engineer called George Luessis indeed works for NASA (he was part of the Chandra project), BUT: upon being asked by Harvard astrophysicist and space buff Jonathan McDowell, he denies any knowledge of this object and the letter and says he didn't make this identification.
So who did make that identification then? Who wrote that letter, if truely there is a letter? Another engineer called George Luessis working for NASA?
Basically, at this point this whole story is falling to (green, glassy) pieces. The rock looks like material that is ubiquitous on Earth. There is nothing in the morphology to link it to a Space Program (let alone the Russian Space Program), i.e. nothing in the composition and morphology to think it is space debris. In fact, there is much in the morphology that makes that highly unlikely. And it is not clear who at NASA, if anyone at all, analysed the rock and "identified" it as "space debris". There is/was a George Luessis working at NASA, but it was not him. So who?
It can be seriously doubted that this green glassy rock is a piece of space debris. There is not a shred of verifiable evidence for it and much speaks against it.