# How come the Voyager probe is leaving the Solar system? **URL:** \ **Category:** Factual Questions\ **Created:** [January 16, 2014, 4:00am UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941 "2014-01-16T04:00:18Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 17, 2014, 6:39pm UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/21 "2014-01-17T18:39:50Z")
On the other hand, there’s not all that much difference between reaching Earth escape speed from low Earth orbit, and reaching the Moon from low Earth orbit. The Moon is pretty high up. ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [January 17, 2014, 6:58pm UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/22 "2014-01-17T18:58:06Z")
Because it has had it up to _here_ with those asteroids. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [January 17, 2014, 7:04pm UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/23 "2014-01-17T19:04:35Z")
Because the return of _Dallas_ was more than it could bear. ---
**Author:** ![Asympotically\_fat](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)\ **Post date:** [January 17, 2014, 7:10pm UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/24 "2014-01-17T19:10:14Z")
> [@Bumbershoot](#): > > Because it has had it up to _here_ with those asteroids. Need asteroid cream ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [January 17, 2014, 8:11pm UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/25 "2014-01-17T20:11:50Z")
> [@Chronos](#): > > “Escape velocity” is, however, a misnomer, in that the correct term is “escape speed”. It actually uses the second, lesser known definition of velocity: **veclocity (n):** speed, when the speaker or writer wishes to seem all science-y. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [January 17, 2014, 11:54pm UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/26 "2014-01-17T23:54:45Z")
> [@Chronos](#): > > On the other hand, there’s not all that much difference between reaching Earth escape speed from low Earth orbit, and reaching the Moon from low Earth orbit. The Moon is pretty high up. Actually, with the right phasing you can get to a trajectory with a zero gravitational specific energy (C3 = 0) with a delta-V budget of about 3.1 km/s, whereas the typical delta-V for a direct Earth to Moon trajectory from an inclination of 31° to 32° is about 4.8 km/s. While the two families of trajectories don’t align, it is conceivable that a substantial error in a translunar injection maneuver could send a spacecraft into interplanetary space, or at least into a very, very long period Earth orbit. The biggest single quantitative navigational risk in the Apollo program wasn’t the actual landing on the Moon, but just successfully getting into Lunar orbit, a feat roughly comparable to flinging a rock from Killarney and hitting a particular block in Halifax, Nova Scotia. (What the Irish have against Canada remains a mystery.) Stranger ---
**Author:** ![Be\_Real](https://avatars.discourse-cdn.com/v4/letter/b/b5ac83/32.png) [@Be\_Real](https://boards.straightdope.com/u/Be_Real)\ **Post date:** [January 18, 2014, 12:15am UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/27 "2014-01-18T00:15:48Z")
> [@Chronos](#): > > Anything moving away from the Sun will find that its speed is decreasing, since it’s got a gravitational force pulling it inwards. Alternately, you can say that its gravitational potential energy is increasing at the expense of kinetic energy decreasing. \*\*\*This is fundamentally no different than noting that when you throw a ball in the air, it slows down while it’s moving upward (just on a much larger scale). > > * * * > > If an object starts off at (or above) escape speed at any given location, and is acted on by nothing other than gravity, it will always remain at (or above) the escape speed for its current location. As the object’s speed decreases, so too does the speed it needs. I like that analogy. ---
**Author:** ![Cheshire\_Human](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Cheshire\_Human](https://boards.straightdope.com/u/Cheshire_Human)\ **Post date:** [January 18, 2014, 7:06am UTC](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941/28 "2014-01-18T07:06:55Z")
> [@Asympotically\_fat](#): > > Need asteroid cream Preparation A [Previous page](https://boards.straightdope.com/t/how-come-the-voyager-probe-is-leaving-the-solar-system/678941.md?page=1)