How long could a starship stay up in orbit?

In the original Star Trek episode “This Side of Paradise,” all of Kirk’s crew have been sprayed by happy-making spores, mutinied and abandoned ship for the colony on the surface of Omicron Ceti III, a Class-M or Earthlike world. Kirk is about to beam down to the planet, too, but then shakes off the influence of the spores, realizing that his commitment to his ship is even stronger.

Assume several things: The Enterprise is in synchronous orbit over the colony. Kirk beams down, leaving the ship abandoned. Starfleet doesn’t come looking for them. The planet’s star is roughly the same size and type as the Sun and at roughly the same distance, and the starship doesn’t automatically use thrusters for station-keeping.

How long, most likely, before the ship’s orbit degrades and it crashes to the surface? A few months? A year or years? Decades? Indefinitely?

Geosynchronous orbit - assuming relatively earth-like setup, that’s 22,000 miles up. there’s very little drag up there. Also assuming the Enterprise is fairly heavy - I’m guessing a few millenia at least. Not sure waht effect a moon would have on disrupting the orbit- would probably turn it into a lock-step one?

Skylab and Soyuz had the problem that at about 150 miles or so, they were barely catching the thin top of the atmosphere. (Geosync is 22,3000 above earth sea level) The giant wings (solar panels) were an added drag to essentally a very light, empty tin can. One factor affecting Skylab was higher than expected solar activity heated the top layer of the atmosphere, causing it to expand, raising the amount of (very thin) air at that altitude and increase the drag on it. Still, the thing lasted from what, 1973 to 1979. ISS at a higher atltitude has less of a problem and still needs the occasional boost IIRC.

The problem with geosynch broadcast satellites is mostly the opposite - getting rid of them, safely. Theya ren’t really going anywhere and you don’t want the dead ones in progressively more perturbed orbits taking out the live ones.

The other way of looking at it is that, as established in several TOS episodes, standard orbit isn’t geosynchronous orbit, they’re just hovering on impulse engines about 100 miles up, as that was the maximum comfortable range for the transporters. In those several episodes, the engines got shut off and falling ensued, and we saw how that turned out in ST: Into Darkness. In this case, the duration of the “orbit” would be until the engines failed, plus a few minutes.

Synchronous orbit over an earth-like planet with an earth-like day length is quite high up. An orbit that high is not going to decay from atmospheric drag and the slight nudges from tides/other bodies are not going to be enough to send it into a planet-intersecting orbit.

I’d think there’d be a good chance that it would still be up there 10000 years later.

The Dragonriders of Pern series posits the star ship that carried the colonists is still in orbit, abandoned, approx 2500 years after arrival.

I would not point to the Pern books as exemplars of scientific rigor. Quite the opposite, in fact.

Orbiting Earth, an uncontrolled geostationsry satellite will drift until it reaches one of two longitudes. This is due to irregularities in the Earth’s gravitational field. But that’s just the short run. In the long run perturbations by the Sun and Moon will cause other changes in its orbit, although I’m not exactly sure what they would be.

Drag is experienced by anything in low orbit, including the Hubble Telescope, which is much higher than most low orbiting objects. Originally, it was over 600 km, but Wiki says it’s at 559 km now. The Shuttle gave it a boost every time it visited, but it hasn’t visited it in a while. The ISS is at about 420 km and it has to be boosted periodically, as well.

In The Making of Star Trek (Roddenberry and Whitfield, 1968), it states that the maximum range of the transporter is about 16,000 miles (Spock gives the figure as 30,000 km in “Obsession”), and that standard orbits vary, depending on a planet’s size, gravity, atmospheric envelope, and so on. I don’t have my copy of the book handy at the moment, but I know it also says the perigee of a standard orbit can vary considerably (10,000 to 20,000 miles is the range that sticks in my mind).

This section of the book is basically a TOS tech manual and was based on the series’ writer’s guide. I’ve always been interested in science, but I lack the expertise to calculate how long it would take for the orbit of a ship the size of NCC-1701 (overall length, 947 feet; maximum width, 417 feet; gross displacement, 190,000 metric tons) to decay around a Class M planet. I do know, however, that it was one of the show’s weakest plot devices. (Note that in “Tomorrow Was Yesterday” the ship entered Earth’s stratosphere with no one at the helm and it didn’t burn up!)

Let’s not forget that in the ST Universe, losing engine power means a very quickly decaying orbit. Just as losing life support means only about an hour of air.*

*When Khan cuts off life support to the bridge in ‘Space Seed’, I’d like to see this scene:

(14 hours later)

KHAN: “How is your air NOW Captain?”
KIRK: “Fine. A little stuffy, but we’re fine. How are you?”

This is also the scenario I envisioned. It never even dawned on me that the ship might be orbiting high enough up to keep its orbit without power. That scenario is not typical.

I happen to have my copy (first edition) right here. I also have the writer’s guide around somewhere, but that was done fairly early and isn’t that reliable.
On page 171 we read

a whole bunch of stuff, put there more to sound scientific than anything else. Now, even 1,000 miles away means it would take a long time to re-enter, since space capsules at the time were a lot lower - the perigee of Gemini 11 was 156.4 nautical miles.

On page 192 it says the range of the transporter is 16,000 miles. There has never been a problem beaming someone up from the other side of a planet, so it must be more than the diameter of a planet.

In Tomorrow is Yesterday, by the way, something is mentioned about automatic helm control holding them there - so they still had engines.

The many times they were in danger from spiraling in without engines always bugged me, since it would take a long time for an orbit to degrade even at 1,000 miles. I can just excuse them since we had only been in orbit for under 10 years when TOS was on, and that bit of drama wasn’t used in TNG.

Not necessarily. Orbits which are essentially Geosynchronous should be possible even at low orbit. All they have to do is match the planets rotational velocity and avoid intersection with the atmosphere. With very powerful propulsion system s at hand that should be fairly easy to do. Whjch means that abandobed vessels might burn up quickly.

That isn’t really an orbit; you are flying round the planet at a selected height under power, but you aren’t in freefall.

In fact you would be subject to the planet’s gravity, so you could, in theory switch the gravity generators off and walk around fairly normally, depending on the height . Drop something out of the window and it will eventually hit the planet (and so on).

Thanks for the correction.

In “The Deadly Years,” though, doesn’t Kirk order Sulu to increase the orbit to 20,000 miles? What would this have accomplished? (I assume he’s referring to its perigee.) :confused:

Does it also mention something about the transporter being line-of-sight?

What is “line-of-sight” when you can beam straight through matter? ST had personnel beaming into and out of buildings, caves, etc. all the time. Only in select plot-driven circumstances was transporter activity “blocked” by what would be called line of sight, and usually by deposits of interference-generating plot-onium.

20,000 miles must be an example of clueless writerdom. I see no reason to be so far out.
I agree with gnoitall about the transporter. Not only do they beam from inside all the time, the Enterprise has moved on right after beaming, and in not too long will not be in line of sight. We never hear that someone can be beamed up in fifteen minutes when the Enterprise gets overhead again. And we see from the establishing shots that the ship is not in a geosynchronous orbit.

However, whenever it uses its phasers to shoot at something on the surface, it is conveniently right overhead. Maybe we call that a plot-synchronous orbit.

One might imagine two possibilities: The ship could be using impulse power to exert a braking force to hold the lower orbit at a lower speed than is dictated by orbital mechanics, which would vector off the starboard bow (based on images from the show); or they might be applying a warp field side-effect to distort the local gravity well in order to make the lower orbit tenable. In either case, if power is lost, the ship would tend to seek a natural orbit, which means that it would start to move away from the planet at the moment that the controlling force is released. I think it would then reach apoapsis somewhere above the geosync band, and its periapsis would probably be near the height of the original orbit. In other words, without power, the ship’s orbit should become very eccentric, from like a thousand miles up to some twenty-five thousand miles. Seems like that would be fairly stable for quite a while.

If they’re using power in some way to maintain a lower “orbit” (in quotes because such a situation isn’t actually an orbit), then if the power fails, they’ll go through a process commonly known as “falling”.

Yes, but… If they can hide from a Klingon ship by keeping a planet in between them (as in “A Private Little War”), does it make a lot of sense that they could detect and lock onto someone through the bulk of the planet (and then beam them through it)?

I can see communicators working through the bulk of a planet, but a transporter lock? How does the matter stream pass through an entire celestial body? :confused:

In “Mirror, Mirror,” Evil Spock reports to Evil Kirk that the planet’s rotation is carrying the primary target beyond the arc of phaser lock, and Evil Sulu asks if he should compensate for it.

Correction: Evil Spock reports to Good Kirk. He only thought he was Evil Kirk at that moment.