I don't remember if there was a reason given in the book, but I know the ship was discovered because one of the fins cut a cable that was being laid. If your ship is only traveling in space, why make wings?

For example, there were no wings on the lunar landers.

Here is the image from the movie showing the tail fin.

enter image description here

  • 4
    Style... fins are cool.
    – BBlake
    Commented Sep 12, 2011 at 10:27
  • 2
    I've always considered fins and such on space craft like flames painted on the side of cars.
    – DampeS8N
    Commented Sep 12, 2011 at 11:37
  • 1
    Its been a while since i've read the book. Was it mentioned that the craft was made strictly for space travel? After all, the retired shuttles were good for space and atmosphereic flight.
    – Xantec
    Commented Sep 12, 2011 at 11:39
  • 2
    @Xantec - technically speaking, shuttles were good for atmospheric gliding descent. I wouldn't go as far as "flight". Commented Sep 12, 2011 at 12:49
  • 3
    I remember an episode of ST Voyager when some technician is criticizing the design of the Delta Flyer, commenting that the fins are not necessary, and he said he did it because they look cool.
    – Sydenam
    Commented Sep 13, 2011 at 20:23

7 Answers 7


"Fins" on real spacecraft are usually for one of two purposes: solar panels or thermal radiators. therefore, those are the most likely purposes for them.

Also note:

the book seems pretty clear the ship is a time travelling US ship. In which case, fins as radiators is most likely. It has no shortage of internal power.

  • Fins have nothing to do with aerodynamics. See the structure of any artificial satellite.. Do you think, their bodies are smart aerodynamic design? :)
    – user931
    Commented Sep 15, 2011 at 15:18
  • Why do you think, sci-fi world's space crafts need solar panels when most often they travel through dark space (or, low-light space)? Sci-fi world's space crafts always have on-board power generators for their super advanced needs.
    – user931
    Commented Sep 15, 2011 at 15:41
  • 2
    I like the idea of the fins acting as thermal radiators. Space is cold, but it is also a terrible thermal medium. If they expected significant heat as a result of entering the black hole they might have built the fins to help cool the ship. Commented Sep 15, 2011 at 17:55
  • @Jack But, still it has nothing to do with aerodynamics design... thermal radiator fins can be attached without supporting/preserving aerodynamic design of space craft system.
    – user931
    Commented Sep 15, 2011 at 19:34

First, we must consider that "Sphere" is less Hard SF and more soft SF, thriller, airport novel and such. So, everything goes (including bipedal, English-speaking little green men).

When the spaceship was first discovered, it was easily determined that this was an alien spaceship. It was beyond the technology possessed by any of the human nations at that time. So, perhaps a spaceship which was radically different from human spaceships, even to the casual observer, was needed to be described. Humans spaceships don't have fins, this one has. Thus, it may be essential to the plot.

Furthermore, when the spaceship was inspected from the inside, it contained many features which were never explained at all. This implies that the builders were far more advanced than us. At one point, it was speculated that the ship may be a sleeper-ship or a time-traveling ship. As, humans are far from inventing anything remotely close, maybe the fins serve some purpose and human can't understand it because they do not have the fundamental knowledge.

Finally, one should stop being anthropocentric while reading SF (at least hard SF), aliens (even humans from the future) do not think or do stuff like us. Also, there are various types of spacecraft yet to invented. Our current spacecraft are based on chemical propulsion and lack fins (except the the Shuttle). But, the recently developed solar sail-based spacecraft are radically different in design.

  • It has been a while since I read the book, and I caught part of the movie last night, which inspired the question. But the ship is massive, I think the book says that it couldn't be lauched from Earth, it had to be assembled in space, which implies to me that is wasn't meant to be flown in an atmosphere. Commented Sep 12, 2011 at 22:46
  • 1
    @JackBNimble "Wasn't built in an atmosphere" isn't the same as "would never enter an atmosphere." Naval ships are built on land, but designed for the sea. It's entirely possible that a vessel would be built in space, where construction doesn't have to fight against gravity, but designed for both space and atmospheric flight.
    – Nerrolken
    Commented May 27, 2015 at 16:25
  • 1
    Seriously, is that wikipedia article's list of "airport novel authors" still there? It's nearly 10 years since I cleared out all the unsourced and derogatory accusations from it, and there it is, accumulating them once again...
    – Jules
    Commented Jul 19, 2016 at 0:10

Currently, interplanetary spacecraft designs assume that the command ship will not be making a descent. That's fine - so long as you keep to your mission plan, there shouldn't be a problem.

However, this spacecraft from ??43 [We don't get a full date from the ship's log] would presumably have been capable of far more than current designs allow for. This vessel had been collecting things from all over the place - that implies something a little faster than a matter/antimatter reactor on the back.

Maybe it wasn't intended to make an atmospheric ascent, but if it needed to make a descent, perhaps it could have been given that capability. It did, after all, survive Earth atmospheric reentry.

I haven't actually seen the design of the ship, most of what I'm talking about comes from prior knowledge of space physics and my interest in speculative science fiction. If it is just a cylinder with a wing and a flag painted on that, well, maybe they thought it was a good place for a flag to go. With this spacecraft, I'll assume that the extra weight wouldn't be a problem.

  • 1
    The book says it likely didn't enter Earth's atmosphere, so much as it just kind of appeared at the bottom of the ocean. Commented Oct 15, 2012 at 19:27

The entire craft was shaped like one big wing


In the novel they explain that the intention of the spacecraft was to travel in time. With the idea of space-time being described in the novel as basically a bowl around the black hole, consider how steep/warped it would be around the anomaly. They had to be prepared to be thrown anywhere so possibly for emergency landings, like crashing into the ocean???


I was under the impression that the large fin on the ship was most likely placed there only to delineate fore from aft on an otherwise circular craft. Perhaps it also housed a communications array of sorts. Also it gave a place to put a cool looking black-and-yellow checkered flag, a distinctly human characteristic.


In most of cases, a spacecraft needs to leave & enter a planet's atmosphere many times. So, aerodynamic design could help in penetrating the atmosphere at high speed, providing lift while countering enormous gravity, and lowering risks associated with heat produced due to friction/drag force offered by atmosphere & so on.

Another thing: Interstellar space isn't always a true vacuum. There are ions and gases spread throughout a ship's path. I have even read some comic stories in which spacecraft travel through nebulae more dense than the atmosphere of any planet. So, aerodynamic designs help a spacecraft travel smoothly in space. Also, there's no disadvantage to the spacecraft in the case of a true vacuum.

  • 2
    Even if there are extremely dense nebulae in space, there would be no need for wings and fins. The purpose of those is to provide lift, stabilization, and control surfaces - none of which are needed in a microgravity environment. Sheer power (and attitude thrusters) can keep you on course, and there's no significant gravity to lift against.
    – Jeff
    Commented Sep 14, 2011 at 17:37
  • 1
    @Jeff, Sachin: please do not conduct extended discussion in comments, that's not what they're for. Use chat if you want to chat. Sachin: remember, be nice.
    – user56
    Commented Sep 15, 2011 at 23:40
  • I don't know who deleted my comments, but its wrong.. There were notable points in that & I was the winner. Now, it seems that I am speechless against Jeff who doesn't know that Bullet train & F-1 cars also based on aerodynamic design..
    – user931
    Commented Oct 22, 2011 at 19:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.