Deadline Hollywood is reporting that Tommy Lee Jones and Brad Pitt are set to costar in a movie that has been described as “Heart Of Darkness” in space entitled “Ad Astra.” The film, due to go into production in September. James Gray co-wrote the film and will direct.

What is ‘Ad Astra’ about?

Pitt is going to play an autistic engineer named Roy McBride. It seems that 20 years previous to the plot, McBride’s father, to be played by Jones, went on an expedition to Neptune in search of alien life. The expedition vanished without a trace. Pitt's character will now head to the solar system in search of his lost father and to find out why the voyage of discovery failed.

Ad Astra’ is not the first time Hollywood has adapted Joseph Conrad’s “Heart of Darkness,” having translated it to the Vietnam War in the movie ‘Apocalypse Now’ with Martin Sheen and Marlon Brando. The original story, published in 1899, depicted how an explorer named Marlow who sails up the Congo River in search of an ivory trader named Kurtz in the heart of Africa. The Conrad story was done for TV in 1993 with Tim Roth as Marlow and John Malkovich as Kurtz.

Why Neptune?

On first glance Neptune seems to be an odd place to search for alien life, The eighth planet of the solar system is out on the outer edge with a surface temperature of -201 degrees C, a mass of over 17 times that of Earth, and an atmosphere that is mainly hydrogen and helium with traces of methane.

Neptune has 14 known moons, the largest of which is Triton, thought to be a captured Kuiper belt object with a frozen nitrogen surface, a water ice crust, and a rocky core. In other words, the Neptunian system does not seem to be a place where alien life could be found, at least as we know it.

The reason that Neptune was chosen as the destination was likely that it is the farthest away official planet in the solar system.

However, if “Heart of Darkness” is being shoehorned into a space adventure, that means that Pitt, as the Marlow character, is going to make some stops along the way. How that scenario is going to be tied to the reality of space travel, where planets do not line up correctly on a flight path, and where a voyage to the outer solar system can take years even with the most futuristic propulsion technology, remains to be seen.

In any case, this movie is the latest in a series of space adventures that include such movies as "Gravity," "Interstellar," and "The Martian."