A new film channels the spirit and traces the lineage of Laika, the first creature ever to orbit Earth.

Laika, a stray dog scooped off the streets of Moscow, launched on the Soviet Union's Sputnik 2 mission in November 1957, just a month after Sputnik 1's liftoff opened the space age. The 11-lb. (5 kilograms) mixed-breed quickly died of overheating and circled Earth as a corpse until April 1958, when Sputnik 2 fell back into the atmosphere and burned up.

Laika was sacrificed to aid humanity's march into the cosmos, her pioneering mission and those of her successors designed to help show that our species could survive jaunts into the final frontier. A new documentary called "Space Dogs" asks us to examine that sacrifice and what it says about us.

Related: Laika the dog and the first animals in space

"This film is about the relationship of another species to us humans. A species that has been used in space history in two ways: both as an experimental object and as a symbol of courage and heroism," directors Elsa Kremser and Levin Peter said in a statement.

"The dogs had to fulfill mankind's dream by conquering the cosmos for them," the duo added. "Their story became a fable, a nascent legend, of a bitterness that we chose to illustrate. 'Space Dogs' is dedicated to these fables and legends, to unknown worlds and to their discoverers."

Kremser and Peter dug up stunning, never-before-seen footage of Laika and other Soviet space dogs. Some of these archival snippets show the pups being prepped for their landmark launches, their poor little bodies bristling with implanted tubes and wires. Other footage depicts post-landing processing of the shorn and wobbly strays fortunate enough to survive their orbital ordeals.

Getting ahold of this priceless historic material was no easy task. Kremser and Peter knew it existed, thanks to tips from scientists and other sources who were involved with the Soviet space program in the 1950s.

"But in the classic Russian archives in Moscow, there were just the propaganda images and very short pieces of all this," Kremser told Space.com.

The Austrian documentary "Space Dogs" follows strays through the streets of Moscow and looks back at the canine pioneers who paved the way to space for humanity. (Image credit: Courtesy of Icarus Films)Eventually, the duo tracked the footage down to the Institute of Biomedical Problems in Moscow, which conducted much of the dog research and monitoring in Laika's day and continues to support the Russian human spaceflight program today.

"In their basement were super-old reels, nearly untouched and not published at all," Kremser said.

She and Peter eventually convinced the Institute to let them use the footage, which had started to show its age. "We made a full restoration and could offer that the material itself was just preserved, and also put into a new context," Kremser said.

That context is complex and artistic. For starters, "Space Dogs" is not chiefly about Laika and her fellow space explorers; the historical footage comprises less than one-third of the roughly 90-minute film. The bulk of the documentary is devoted to strays on the streets of modern Moscow, especially one young dog with floppy ears who roams the city with charismatic enthusiasm.

Related: Pioneering animals in space (photos)

Indeed, Kremser and Peter didn't set out to make a space-related film at all. The original idea involved simply profiling a pack of stray dogs, creating a multilayered "cinematic experience that is fully dedicated to them," Peter told Space.com.

"One layer, let's say, is a metaphor," he added. "We found it simply interesting that they pop up at the moment when human control is fading, when the city is cracking, the city is partly falling apart. These creatures have their unique space to conquer."

The directors also found stray dogs to be appealing protagonists, with intriguing social interactions and a language all their own. In addition, Kremser and Peter wanted to interrogate how humanity views animals.

In storytelling and nature documentaries, "they always put very clear roles on animals," Kremser said. "Nature in these terms is always very far away or very humanized, and we wanted to [shine] a different light on this topic."

That light blazes through in "Space Dogs." The impressionistic Austrian documentary gives a pup's-eye view of Moscow, showing us a blurred and blended place on the margins of the human and canine worlds. And the Laika angle, which took shape after Kremser and Peter read about the pioneering dog's street origins, gives the film additional depth and emotional heft, letting it reach truly cosmic heights.

After all, painting such a detailed portrait of the dangerous, complex and frequently joyful life of a Moscow street dog gives us a much better appreciation of what those Soviet space scientists sacrificed in the name of progress more than half a century ago. And it reminds us that perhaps we shouldn't be so quick to make such sacrifices in the future.

"Space Dogs" was released in an exclusive virtual cinema launch Sept. 11 via Anthology Film Archives, Alamo On Demand and Laemmle Theatres. The documentary will be released nationwide beginning on Sept. 18. For cities and playdates, visit http://icarusfilms.com/other/playdate.

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.