# Another Kerbal Space Program question: Are the navballs real? **URL:** \ **Category:** Factual Questions\ **Created:** [December 23, 2019, 12:34pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286 "2019-12-23T12:34:57Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [December 23, 2019, 12:34pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/1 "2019-12-23T12:34:57Z")
The video game _Kerbal Space Program_, which I know has many fans on this board, uses a device called “[navball](https://wiki.kerbalspaceprogram.com/wiki/Navball)” as the primary navigation tool. Essentially, they are spherical indicators, not unlike the artificial horizons on airplanes, from which you can read all sorts of information, such as the spacecraft’s attitude, velocity vector, direction in which you need to thrust for the next scheduled maneuver, etc. Are these devices real, in the sense that they are actually used in spacecraft? They seem to be superbly useful for visualising all this navigational information in one handy instrument. Yet, when googling “navball” pretty much all hits I get are to Kerbal-related websites. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [December 23, 2019, 1:00pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/2 "2019-12-23T13:00:38Z")
You need to search for “Attitude Indicator” and “Flight Director Attitude Indicator” and “Space Shuttle Attitude Director Indicator”. That’s the real-world equivalent, and the closest thing we had to an actual navball. Here’s a picture of [one similar to that used on the space shuttle](http://www.space1.com/Artifacts/Space_Shuttle_Artifacts/Controls___Displays/Space_Shuttle_ADI/space_shuttle_adi.html) until they were replaced with [glass cockpit instrumentation](https://external-preview.redd.it/5wMFnqTMtLb_VPQYzA08qi_V6UpqZydr93a2Y_u0fWs.jpg?auto=webp&524b592b) in early the early 2000s. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 23, 2019, 3:27pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/3 "2019-12-23T15:27:00Z")
> [@Bear\_Nenno](#): > > You need to search for “Attitude Indicator” and “Flight Director Attitude Indicator” and “Space Shuttle Attitude Director Indicator”. That’s the real-world equivalent, and the closest thing we had to an actual navball. Here’s a picture of [one similar to that used on the space shuttle](http://www.space1.com/Artifacts/Space_Shuttle_Artifacts/Controls___Displays/Space_Shuttle_ADI/space_shuttle_adi.html) until they were replaced with [glass cockpit instrumentation](https://external-preview.redd.it/5wMFnqTMtLb_VPQYzA08qi_V6UpqZydr93a2Y_u0fWs.jpg?auto=webp&524b592b) in early the early 2000s. I agree. The navball is a combination of the attitude indicator and several other values. In actual spacecraft, this set of information isn’t all displayed in the same place. Your 2nd link isn’t working for me. Hopefully [this link](https://www.reddit.com/r/PanelPorn/comments/1zvc1y/the_space_shuttle_glass_cockpit_3014_2000/) is the one you intended and will work. [This discussion](https://www.reddit.com/r/space/comments/29j7ge/breakdown_of_boeing_cst100_instrument_panel/) links to a picture of the Boeing CST-100 Starliner control panel, and it appears to have a similar attitude indicator. Not surprisingly, SpaceX doesn’t try to emulate analog instruments. [Here](https://www.cnet.com/pictures/spacex-dragon-v2-spacecraft-unveiled-by-elon-musk-pictures/14/) is the prototype display for the Crew Dragon. ---
**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:** [December 23, 2019, 6:28pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/4 "2019-12-23T18:28:27Z")
There is no device which can directly measure your velocity. If anything in a spacecraft is displaying a velocity, it must be computing that either from the integral of acceleration measurements, or the derivative of position measurements. And once you’ve got a device computing that, the question is just one of how you’re going to display that information. ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [December 24, 2019, 1:33pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/5 "2019-12-24T13:33:59Z")
Ignorance fought. Thanks! ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [December 25, 2019, 4:34am UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/6 "2019-12-25T04:34:27Z")
> [@Chronos](#): > > There is no device which can directly measure your velocity. If anything in a spacecraft is displaying a velocity, it must be computing that either from the integral of acceleration measurements, or the derivative of position measurements. And once you’ve got a device computing that, the question is just one of how you’re going to display that information. In the atmosphere pressure difference between the pitot tub (facing forward) and static port (on the side) gets you indicated air speed which differs from true airspeed and ground speed. Of course does not work in space. Brian ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [December 25, 2019, 7:00am UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/7 "2019-12-25T07:00:35Z")
> [@Chronos](#): > > There is no device which can directly measure your velocity. If anything in a spacecraft is displaying a velocity, it must be computing that either from the integral of acceleration measurements, or the derivative of position measurements. And once you’ve got a device computing that, the question is just one of how you’re going to display that information. The navball doesn’t display velocity, but heading relative to the body you’re orbiting. I presume this is what the OP meant by “velocity vector.” ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [December 25, 2019, 10:22am UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/8 "2019-12-25T10:22:48Z")
> [@Gorsnak](#): > > The navball doesn’t display velocity, but heading relative to the body you’re orbiting. I presume this is what the OP meant by “velocity vector.” Indeed, the navball indicates only the direction you’re going relative to the orbited body, but not the speed - that is indicated separately. If the term velocity vector does not capture that, then I stand corrected. Thanks. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [December 25, 2019, 12:30pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/9 "2019-12-25T12:30:36Z")
Given a known light source you could theoretically calculate velocity from the red/blue shift. Brian ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 25, 2019, 1:32pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/10 "2019-12-25T13:32:14Z")
> [@Gorsnak](#): > > The navball doesn’t display velocity, but heading relative to the body you’re orbiting. I presume this is what the OP meant by “velocity vector.” I think **Chronos** ’ point is that the navball isn’t a readout from a specific instrument. It’s a display for a navigational computer, and the values are computed based on many different sensors. So there is no reason for these values to be displayed & grouped in this specific way. As far as I know, there is no standardized way to display spacecraft GN&C (guidance, navigation and control) information. The navball is one of many different implementations. And it’s probably optimized for a consumer game typically played on a single screen, while an actual spececraft has a whole wall full of monitors and/or gauges. ---
**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:** [December 25, 2019, 3:17pm UTC](https://boards.straightdope.com/t/another-kerbal-space-program-question-are-the-navballs-real/845286/11 "2019-12-25T15:17:59Z")
That said, the criteria used by the designers of the game for how to group and display pieces of information were presumably “easy for a human to read and intuitively understand”. And those are also criteria that real spacecraft instrument designers would be using. So it’s not out of the question that some future spacecraft might use the navballs as a model for how to do it, if it turns out that the game designers did it well. If those future spacecraft designers even find a need for information displays, that is. It’s probably more likely that navigation and control will be handled entirely by the onboard computer, with therefore no need for any sort of information display to the humans on board. Except possibly as a form of entertainment, like the displays to the passengers on airlines of the plane’s course, altitude, and speed. But then, if the passengers want in-flight entertainment, they might just be playing Kerbal Space Program itself.