Juno development, launch, and cruise, Including Earth flyby imaging Oct 9 2013 Options

[jasedm]

Lovely image. In today's sharp-focus, 20m/pixel world, a blurry image of the earth/moon system still has the power to be moving.

[dood]

Just before launch I was asked to adapt a paper scale model (original by John Jogerst) for the Juno Project to link to their website. I completed it prior to launch and turned it over to Juno, where it is now waiting to be "formatted" for the site. Since that step has been taking quite a while now, I thought I'd mention that I've made the 1:50 scale Juno kit available on my website (http://spacecraftkits.com) for free download. It's pretty accurate, and when assembled it rivals the professionally created Juno scale models in appearance. -dd

[djellison]

I actually built several of Dave's models from Spacecraft Kits about 14 years ago....and only learned that Dave made them just a few months ago! They're great - the Magellan one still survives!

In case you can't find it immediately - Juno's here : http://spacecraftkits.com/free.html

[Paolo]

no one seems to have noticed this yet, with some interesting technical details
JUNOCAM IMAGES THE STARS

[TheAnt]

Oh I did see that one, but were rather expecting one of you more active guys to post about the Big Bear / Waggon image.

[Paolo]

some action at last:

On June 20, flight controllers commanded the spacecraft to test opening and closing the external cover that protects its main engine, and to fill the propellant lines that supply the engine with liquid oxygen and hydrazine, in preparation for its upcoming deep space maneuvers, slated for Aug. 30 and Sept. 4.

"liquid oxygen"?!?

[propguy]

some action at last:



"liquid oxygen"?!?

I am new to this site, but as the Juno propulsion lead I can say that we did not load LOX (sure would raise the ISP though). The oxidizer is N2O4 (specifically MON3 which is typical for biprop usage). P.S. we are nearing the Deep Space Maneuvers (8/30 and 9/5) where we get to use the biprop portion of the system for the 1st time. Go Juno!

[Vultur]

I am new to this site, but as the Juno propulsion lead I can say that we did not load LOX (sure would raise the ISP though). The oxidizer is N2O4 (specifically MON3 which is typical for biprop usage). P.S. we are nearing the Deep Space Maneuvers (8/30 and 9/5) where we get to use the biprop portion of the system for the 1st time. Go Juno!

Apologies if this should be obvious, but I can't seem to find the answer on Google... I assume LOX is not used because it is so cryogenic... is the N2O4 cooled or otherwise temperature-controlled? If not, does the dissociation into NO2 make a difference as an oxidizer (or does the NO in the MON3 solution keep the N2O4 from dissociating into NO2 somehow?)

[propguy]

Apologies if this should be obvious, but I can't seem to find the answer on Google... I assume LOX is not used because it is so cryogenic... is the N2O4 cooled or otherwise temperature-controlled? If not, does the dissociation into NO2 make a difference as an oxidizer (or does the NO in the MON3 solution keep the N2O4 from dissociating into NO2 somehow?)

Actually it is a good question. We did not use LOx for obvious reasons (hard to store for years with zero loss). The biprop systems are all based on essentially room temperature storage so while there is some equilibrium value of NO2 (something like 15% at room temp) there is no real data to say if this actually lowers ISP since this is same conditions used for engine qualification and acceptance test. Since I am not a chemist or even a chem. E I do not know if the performance would rise if we lowered the NO2 percentage by cooling the propellant. Beyond that I cannot say (ITAR limits and such, sorry).

[Vultur]

OK, thanks.

[propguy]

Almost ready for DSM1. Prop tanks are up to pressure and system configured for the burn. Sequence starts Tuesday 8/28 and runs for 48 hous till the burn. Whoohoo!
Juno Website Link

[Paolo]

good luck! keep us updated please!

[Bjorn Jonsson]

The burn was successful:

http://www.nasa.gov/mission_pages/juno/new...no20120830.html

[propguy]

The burn was successful:

http://www.nasa.gov/mission_pages/juno/new...no20120830.html

Sorry for no news in a few days, but it was a very busy weekend. The burn was great! We missed the predicted burn time by only 4.4 seconds (out of 1775 seconds). The nav folks said we hit the planned DV to within 1 m/sec (344.15 was the commanded value). The program for many reasons decided to delay the 2nd burn until 9/14. Gave us some time off and now we are fresh to work DSM2. After that burn we will have consummed ~1/2 of the propellant we launched with and will be aimed back at Earth for the flyby next year. That will impart more DV than if we burned all the prop in the system (planets sure are nice prop systems too) and send us on a path to Jupiter.

[TheAnt]

.... After that burn we will have consummed ~1/2 of the propellant we launched with and will be aimed back at Earth for the flyby next year. That will impart more DV than if we burned all the prop in the system (planets sure are nice prop systems too) and send us on a path to Jupiter.

Thanks for the update on your game of planetary billiard.