Live coverage of Juno's Jupiter Orbit Insertion [video] • Hacker News Board

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#21

Post by ragazzina » Tue, Jul 05, 2016, 8:02 AM UTC

curiousgal wrote: post #17

This cracks me up! Jupiter's moons were named after Jupiter's mistresses. Juno was his wife..

"The god Jupiter drew a veil of clouds around himself to hide his mischief, but his wife, the goddess Juno, was able to peer through the clouds and see Jupiter's true nature."

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#22

Post by dcuthbertson » Tue, Jul 05, 2016, 9:23 AM UTC

Benjamin_Dobell wrote: post #20

curiousgal wrote: post #17

This cracks me up! Jupiter's moons were named after Jupiter's mistresses. Juno was his wife..

> Juno was his wife.. Was...? Now that's some dedicated faith, still practising Ancient Roman religions!

Was is fine. Those gods have passed on to myth and legend.

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#23

Post by jryle70 » Tue, Jul 05, 2016, 12:05 PM UTC

Stupid question in general. Given how long it takes for a spacecraft's signal to reach earth, I suppose we can use the time difference to calculate the distance from a spacecraft such as New Horizon to earth. But how do we know its exact location at any given moment? What are the equivalence of GPS and cell towers in space?

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#24

Post by Agathos » Tue, Jul 05, 2016, 12:10 PM UTC

Benjamin_Dobell wrote: post #20

curiousgal wrote: post #17

This cracks me up! Jupiter's moons were named after Jupiter's mistresses. Juno was his wife..

> Juno was his wife.. Was...? Now that's some dedicated faith, still practising Ancient Roman religions!

So if I say, "Darth Vader was Luke's father," do you have to remind me that Star Wars isn't real?

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#25

Post by greeneggs » Tue, Jul 05, 2016, 12:34 PM UTC

jryle70 wrote: post #23

Stupid question in general. Given how long it takes for a spacecraft's signal to reach earth, I suppose we can use the time difference to calculate the distance from a spacecraft such as New Horizon to earth. But how do we know its exact location at any given moment? What are the equivalence of GPS and cell towers in space?

This story partially addresses your question. It doesn't have enough details.

http://www.npr.org/2016/07/03/484259562/star-trackers-help-j...

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#26

Post by pmontra » Tue, Jul 05, 2016, 12:36 PM UTC

"A plugin is needed to display this content". Flash again?

Here's a recording https://www.youtube.com/watch?v=zfIqnpqPFbI Applauses at 1:23:30

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#27

Post by [deleted] » Tue, Jul 05, 2016, 12:37 PM UTC

jryle70 wrote: post #23

Stupid question in general. Given how long it takes for a spacecraft's signal to reach earth, I suppose we can use the time difference to calculate the distance from a spacecraft such as New Horizon to earth. But how do we know its exact location at any given moment? What are the equivalence of GPS and cell towers in space?

[deleted]

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#28

Post by Rooster61 » Tue, Jul 05, 2016, 1:30 PM UTC

I didn't realize Juno would have such a large capture orbit. 54 days and change to complete one pass. Makes sense though. They way they are skirting the Ionian radiation torus is pretty slick.

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#29

Post by mturmon » Tue, Jul 05, 2016, 2:16 PM UTC

jryle70 wrote: post #23

Stupid question in general. Given how long it takes for a spacecraft's signal to reach earth, I suppose we can use the time difference to calculate the distance from a spacecraft such as New Horizon to earth. But how do we know its exact location at any given moment? What are the equivalence of GPS and cell towers in space?

Because so many constraints are needed (position, pose, velocity) there is no simple single answer. Here is a summary -- https://solarsystem.nasa.gov/basics/bsf13-1.php

Skip down to "Navigation Data Aquisition"

Re: Live coverage of Juno's Jupiter Orbit Insertion [video]

#30

Post by travelton » Tue, Jul 05, 2016, 2:25 PM UTC

jryle70 wrote: post #23

Stupid question in general. Given how long it takes for a spacecraft's signal to reach earth, I suppose we can use the time difference to calculate the distance from a spacecraft such as New Horizon to earth. But how do we know its exact location at any given moment? What are the equivalence of GPS and cell towers in space?

Don't have all the answers, but last night, on the webcast, they were explaining that the spacecraft uses the stars for navigation [1].

In addition, instead of wasting valuable power for radio transmission, they send a simple tone back to Earth [2]. With that, they can determine if various events were successful (tones are sent at specific event times), also calculate the changes in speed/rotation using doppler shifts from the "tones" [3] (validating the engine fired, current spin, etc)

[1] https://solarsystem.nasa.gov/basics/bsf13-1.php

[2] https://spaceflightnow.com/2016/06/30/juno-switched-to-autop...

[3] https://solarsystem.nasa.gov/basics/bsf6-4.php