From the poem and operetic adaptations Aniara is an epic of extinction, inspired by Martinsen gazing up at the Andromeda galaxy through a telescope one exceptionally clear evening in 1953, shortly after the Soviet Union conducted their first H-bomb test. He experienced sensations of being on a spaceship. I think if you asked this question of Harry Martinsen at the time he wrote it, the answer would simply be, no.
There is a bit of confusion about the clip in question, as it may not be included in every releases of the film. Directors had commented that a different US release was made because the original showed an erect penis, which could not be released in the US. And the following review of both the opera and the film seem to conclude that the clip in question is not shown in the main release:
The film comes nearest to the original's poetic force in its final scene, in which the image of the Aniara as a galactic sarcophagus is fully realized, all life within extinguished, still light-years distant from Lyra.
They were obviously reviewing a different release of the film.
Concerning the modern film adaptation and the clip in question - as seen in the US - what is currently available from interviews and reviews seem to be conspicuously silent about that except for Variety magazine which obliquely calls the ending "a cryptic, ironical fadeout." This implies at least one reviewer considers the intent to be somehow ironical. Did they imagine that had the passengers not given up hope, they - or their species at least - would be OK? I take that interpretation with a grain of salt given the span of time they would have had to endure, and the finite amount of energy this sunless voyage afforded them. The intent of the film was very clear to me that humanity at least would end. It remains an extinction event; nowhere to go to, and nowhere to return to.
But the fact does remain that the poem ends in complete endless drifting, and the film included that clip, for one reason or another, and that clip is never once even spoken about on the Internet. At this early point in the film's life cycle we only have deductive reasoning.
The film industry in general does not like dead ends, as director Pella Kågerman notes in an interview with Cautionspoilers.com last month. When asked why this classic story has not been adapted to film before, Pella responded:
Pella: I think because it is so dark, it’s hard to get money for it, so we had to work a lot with hope. The only demand that the daughters of the writer had, was for us not to change the ending.
At one point we actually pitched this film in Hollywood for a famous agent and he was following the story until we came to the end, where he was like, “But one survives…”
SARAH: They’ll always say you’ve got to have a survivor, or a dog survives, or something like that.
So there was certainly pressure for this adaptation to carry something forward, if for no better reason than to make room for a sequel (pronounced: $$$$). As mentioned earlier, this film is young, and the social pressure to remain true to Martinson's theme are very compelling. Putting down in ink that you just made a movie about the cycle of life would be tantamount to sacrilege.
There are other interpretations which share the sense that the story at least deserves a cycle rather than a finality:
A contemporary adaptation of the poem - which is in fact 103 poems, or cantos - was conducted by The Crossing Choir which notes a connection between the Matteson story and Asian mythology, and choreographer Antti Silvennoinen
I had talked with [artistic] director [Donald Nally] there's a connection
between Aniara and asian mythology and culture so I'm gonna use
some ideas of Taoism for example very circular movements and sort of
martial arts based energy
Taoist practitioners believe in a circular "path of return"—a movement from the myriad things of the world back into wuji. The Immortals, or those who have entered the Tao, are those who have completed this "path of return." A Taoist interpretation of the poem would be inclined to extend the poem's forever drifting toward Lira out to arriving at Lira, and a circular path from the manifest Taiji and the unmanifest Wuji, via the mechanism of Taiji, and then back in the definitive yin and yang cycle enveloping all things.
If this final scene depicts panspermia, it would the accidental panspermia proposed in 1960 by astronomy professor Thomas Gold. What arrived in Lyra may well have contained viable Earthly microorganisms. According to Wikipedia there are documented viable Earthly bacterial spores that are 40 million years old that are very resistant to radiation, and others able to resume life after being dormant for 25 million years,
So no canonical answer agrees that the clip in question had the intent to convey panspermia, and even if it were true no such agreement will likely be printed; modern science does not reject the possibility that accidental panspermia would be the outcome of this version of the film.