In Star Wars - hyperspace travel has some limitations. For one, you can't get to close to a gravitational body.

We see this in Ep IV - the Falcon must lift off on repulsorlifts and travel at sublight away from Tatooine before entering hyperspace.

I seem to recall something in the novelization about "six planetary radii" when it explained how the Death Star moved using hyperspace and sublight engines.

In the now Legends canon - this gravity limitation was the explanation for the Kessel Run being measure in parsecs (basically, how much of a corner a ship can cut past a cluster of black holes), and even used tactically by the Empire with their Interdictor cruisers.

So, in the new film, how could the Falcon fly through hyperspace to get under the Starkiller Base shields?

  • 2
    Some discussion of this on this thread...someone more knowledgeable then me would have to find specific canon references to back this up, but posters on there claim that "going into and out of hyperspace in the atmosphere of a planet happens on multiple occasions in the Clone Wars cartoon", and also that this was dangerous so that ships may have had a safety system normally causing them to drop out of hyperdrive when they get too close to planets, but that it could be disabled.
    – Hypnosifl
    Commented Jan 5, 2016 at 22:52
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    Having the option of ignoring the safeties on a hyperdrive would render Interdictor cruisers useless. They threw the book out the window.
    – Mazura
    Commented Jan 15, 2016 at 0:28
  • To add to my comment above, I just watched the episode Jedi Crash, and it does feature a ship whose hyperspace drive is accidentally triggered while it's still in a planetary atmosphere, it jumps to hyperspace with no apparent ill effects. I'll be on the lookout for any episodes showing them dropping from hyperspace directly into a planet's atmosphere.
    – Hypnosifl
    Commented Feb 11, 2016 at 17:13

5 Answers 5


There are actually likely three different gravity well radii that impact hyperspace travel. The first is the true no go zone. You travel through here you die (I.e., the center of a star as referenced by Han in IV).

Then there is likely to be a larger buffer in which the ship will take damage but is not lethal. You can travel here if you know what you are doing and would travel into this part of a gravity well would likely only occur in emergencies.

The third distance is the safe buffer. Normal hyperspace travel would be outside of this radius. This would be what Nav computers and the safety interlocks on the hyperdrive would be set to work with. However if you know what you are doing and have very carefully performed your calculations you can operate between this radius and the damage radius with no ill effects.

For episode VII, the travel to the planet almost certainly was inside the normal safe buffer region and possibly inside the potential damage region. Damaging the ship would have been considered a valid trade off in exchange to getting under the planetary shield.

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    Do you have sources for any of this, or is it speculation?
    – user45623
    Commented Jan 6, 2016 at 3:08
  • This is just speculation based on real world analogies. I would have to imagine that there is a safety buffer, especially given that ships in the Star Wars universe are not perfect. It is also reasonable to expect that it is not a white-black line of safe-dead with respect to gravity wells. To me it is reasonable if there is a grey area of increasing damage. Commented Jan 6, 2016 at 3:12
  • My impression was that Han engaged the safety by hand and let the planet pull him out of hyperspace. The other option is that he eyeballed it while traveling at light speed. Commented Feb 20, 2016 at 19:59
  • There are occasional references to a safety margin. For instance in Wraith Squadron we're told "you can fly straight into the system, and if you hit a gravity well before you reach your destination, it pops you back into real space before you're close enough to endanger you" (p. 130).
    – Cadence
    Commented May 17, 2020 at 16:33

It was established in Legends sources (I think the Essential Guide to Vehicles and Vessels was one, but I seem to have lost my copy) that every hyperdrive has a built-in failsafe that cuts it off when too close to a large gravitational body (such as a planet or star). It is supposed to be dangerous and difficult or impossible to override this failsafe, which is why the Interdictor-class Star Destroyers are possible (see http://starwars.wikia.com/wiki/Hyperdrive/Legends )

However, in A New Hope, Han mentions in reference to hyperspace travel, "Without precise calculations we could fly right through a star", suggesting that either these failsafes don't exist in movie canon, or that he has managed to disable the failsafe on the Falcon (not too hard to believe given how heavily he has modified other aspects of the ship).

Alternatively, we see evidence throughout The Force Awakens that technology has advanced in the three decades since ROTJ, so perhaps the failsafes have gotten more precise.

A more difficult question is how Han manages to deactivate the hyperdrive manually (we see him pull the lever!) while traveling faster than the speed of light with such precise timing that he ends up meters from the surface.

  • As for your last question, maybe we could imagine that gravity has a strongly repulsive effect in hyperspace that slows down approaching ships, so by the time they approached the planet their speed was far lower than the speed of light.
    – Hypnosifl
    Commented Feb 20, 2016 at 14:31

The rules changed over time across Legends and Canon

Originally, as you mention, Legends continuity established that hyperspace travel explicitly couldn't happen within a planet's gravity well. This was ingrained in Legends canon at least as early as 1991, where it forms the basis for a couple of plot points in the Thrawn Trilogy:

Han cut himself back into the radio circuit. "—said that if I had a slave circuit they could get me in a lot faster," Luke was saying. "A hyperspace jump as close to Nkllon as the gravity well will permit, then just a few minutes of cover before I'd be in the planetary umbra and could go the rest of the way in on my own."

Heir to the Empire: The 20th Anniversary Edition, page 165-166 of Kindle edition

This was still the rule as of 2007, judging from a later Timothy Zahn book:

One glance at the half dozen mismatched ships rising behind them was all he needed. "Pirates," he snapped to the others, throwing power to the engines and angling the ship upward. Facing pirates deep inside a planet's gravity well, with no cover and no chance of quick escape to hyperspace, was about the worst situation a pilot could encounter.

Allegiance, as excerpted in Heir to the Empire: The 20th Anniversary Edition

The ability to pull ships out of hyperspace and prevent them from re-entering it is also the point of the EU's Interdictor cruiser, as mentioned in the question:

During large space engagements, escape into hyperspace is often the last recourse for wounded starships. However, the Empire removed this tactic from the Rebel Alliance protocols by creating the formidable Interdictor cruiser. The Interdictor has four gravity-well projectors that can mimic a mass in space, thereby interrupting hyperspace travel. Nearby vessels are automatically prevented from engaging hyperdrive engines, and any starships passing through the area via hyperspace are suddenly forced into realspace.

The New Essential Guide to Vehicles and Vessels, page 69: Interdictor Cruiser

While this description's use of "automatically" leaves open the possibility that this is just a safety measure on ships' hyperdrives, presumably the Alliance would have been able to tactically override their ships' safety measures to counteract the effectiveness of Interdictors if that was the only restriction.

However, The Clone Wars series a couple of years later would come to ignore many of the "rules" that had been established by the Expanded Universe, including the properties of hyperspace—see also "Are there any Star Wars Canon usage of 'Hyperdrive Radio' prior to Rogue One?" The 2009 episode "Jedi Crash" includes a hyperspace jump within a planet's atmosphere, leading to an implicit retcon that jumping to hyperspace from a planet wasn't impossible, just dangerous—see "How did this ship jump to lightspeed within a gravity well?" Since the show was (mostly) released before Disney's acquisition of Lucasfilm, these events also became part of Legends continuity and overwrote the earlier categorical ban on in-gravity hyperspace.

In the specific case of The Force Awakens and jumping that close to a planet, this definitely seems like it would have been impossible under the Heir to the Empire rules (where it would have taken "minutes" to reach the planetary umbra, let alone the atmosphere, compared to the seconds it takes in The Force Awakens to get from the exit point to literally hitting the ground). However, it's less clear what was possible to do with hyperspace in Legends after The Clone Wars aired.


The gravity well projected by a planet is strong enough to pull ships from hyperspace. ditto for interdictor cruisers. They only way that I can see for han to do this, is to delete the planetary information off the his navigation computer, then plot a course to a point just past the shield layer. which brings up a couple of other issues. One being, the falcon wouldn't be able to withstand that much deceleration in an atmosphere. nevermind, the first point is enough.


"...One being, the falcon wouldn't be able to withstand that much deceleration in an atmosphere"

As far as my understanding of fictional theoretical hyperspace physics goes, ships do not really "accelerate" or "decelerate" in and out of hyperspace. They simply enter and leave. Hyperspace is a subspace corridor separate from real space where speed and acceleration are relative. Phrases like "make the jump to light speed" confuse the issue a bit. "Light speed", as an actual measured speed, would be woefully inadequate when talking about traversing the monumental distances in the Star Wars Galaxy. Hence, "jumping to light speed" is simply a euphemism Han uses to describe entering hyperspace. From what I understand, the actual speed one is going when entering hyperspace is roughly the speed they will be going when they exit. Enter at a standstill and you will exit at one.

On a further note, The Falcon was a fast ship, not because of the power of its engines, but because of the power of its computers' ability to calculate hyperspace jumps in such a way that trips could be made shorter not only in time but in distance. Calculating their path through space and around celestial bodies in a much more efficient way than lesser ships. This feeds back into the notion of "parsec" being used as a determiner when discussing how fast the Falcon is with Luke. The ship was extremely "fast" at the Kessel run due to its ability to calculate the run with the shortest hyperspace route possible. In Legends, the Kessel run was dangerous and difficult due to the extreme density of stars and black holes in that region of space, making efficient hyperspace route calculations very difficult.

  • No, it had powerful engines - "point 4 past lightspeed" - it could skirt closer to the gravity well because it was fast
    – HorusKol
    Commented Aug 16, 2016 at 22:19
  • Wouldn't it be weird to have a clapped-out equivalent of a smuggler's Dhow to have "faster computers" than the equivalent of a US Navy CVN? Commented May 17, 2020 at 6:59

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