Juno Spacecraft - Who thinks they're a NASA nerd?

[John O.]

Ok!

I've got a challenge for all you data hounds and NASA spec nerds out there.

The Juno spacecraft is launching in August of this year to travel to Jupiter - as such, it is the first spacecraft to use solar power beyond Mars.

I'm doing a paper on photovoltaic power for spacecraft applications and there's one particularly useful tidbit of information I need to know about Juno - What kind of solar cells are on the spacecraft? I have a strong theory they're just gallium arsenide multijunction cells but I need to know for sure, and all this damn NASA posturing about how they're special new cells designed for low-light conditions and high radiation environments, blah blah blah. I need to know if they're just the next step in GaAs MJ cells or if they're something specifically new.

Sounds like an easy question and I assure you I am not an idiot , I have looked high and low - on the NASA site, on Wikipedia, hours on Google, on Lockheed Martin's website (they're building them), and I cannot find ANYTHING that will actually tell me what the PV modules are made of.

All the NASA PR announcements say is:

Juno benefits from advances in solar cell design with modern cells that are 50 percent more efficient and radiation tolerant than silicon cells available for space missions 20 years ago. The mission’s power needs are modest, with science instruments requiring full power for only about six hours out of each 11-day orbit (during the period near closest approach to the planet). With a mission design that avoids any eclipses by Jupiter, minimizes damaging radiation exposure and allows all science measurements to be taken with the solar panels facing the sun, solar power is a perfect fit for Juno.

Go. Someone find it!

FYI you have... 16 hours. Paper's due at 5 PM tomorrow and this is the last damn thing I need to tie it up.

 

[John O.]

False alarm! I found it 10 seconds later. It's the same kind of Low Intensity Low Temperature GaAs modules they used on Dawn and Rosetta. Call off the search!

 

[publiusr]

After the Fukashima disaster, we will probably see more protests if a Cassini mission is tried again.

And here I am wishing for Orion. Fat chance of that being built as it stood.

 

[sojourner]

Yeah, the original Orion project would never have - flown? gotten of the ground? hmmm, can't decide on a pun to use.

The politics of that project would have been impossible except as a response to alien invasion.

 

[John O.]

God, I really hope the Fukashima disaster doesn't have too much of an effect on nuclear space propulsion. In perhaps a bizarre stroke of good fortune, there actually aren't any nuclear powered probes or spacecraft on the immediate horizon that I can think of (but I'm not 100% up on the state of the art someone might be able to correct me on this), so by the time the next nuclear powered spacecraft is under public debate, this Fukashima thing will be at least a couple years behind us. Besides, from what I understand, RTG reactors are ridiculously protected from atmospheric breakup in the event of a catastrophic launch failure. I'm sure the environmentalist groups won't see it this way, but I think there's just as much of a ridiculous NASA factor of safety on those things as there is on everything else they fly. JIMO, was, I believe going to be powered by a nuclear-electric hybrid but it never got very far before it was cancelled.

I'm finishing up my Masters in Aero in December and I'm currently working to try and get on as a PhD candidate with one of the top nuclear propulsion researchers in the country at the nuclear eng. dept of my university. I'm under no illusions about the fact that I will probably be his age (~79) before I see my work in practice.

 

[sojourner]

Yeah, when I used to live closer to KSC I can remember watching on the local news about idiot protestors with signs every time an RTG powered probe was launched.

 

[publiusr]

Here is a little secret for you. Remember the tiny rover with your screen name? It had a little something called a warm electronics box (WEB.) Guess what was in it. Since the thing actually got power from solar panels, nobody thought any plutonium was in it. So, in the future, just place some solar panels/radiators to either side of your NERVA to draw attention--just like they did on the DY class

 

[Dukhat]

So, in the future, just place some solar panels/radiators to either side of your NERVA to draw attention--just like they did on the DY class

It took me a few re-readings to actually figure out what you were talking about here. But now that I get it, that's pretty funny.

 

[John O.]

I actually just found out tonight I'm going to be doing research over the summer on a new design called a Helicon IEC thruster in the Nuclear Engineering Lab here on campus

Inertial Electrostatic Confinement is a relatively developed approach towards a fusion thruster, but adding a helicon to the mix is a brand new concept of only the last year or so. We hope to develop a fundamental understanding of the plasma physics going on in the exhaust and hopefully evaluate it as a potential high thrust, high specific impulse electric-nuclear hybrid thruster of the future.

 

[STR]

After the Fukashima disaster, we will probably see more protests if a Cassini mission is tried again.

Most people in America think "Japan was fixed" as soon as CNN stopped doing hourly updates riddled with crap reporting, improper use of measurements and statistics, and all around unjustified paranoia.

 

[John O.]

After the Fukashima disaster, we will probably see more protests if a Cassini mission is tried again.

Most people in America think "Japan was fixed" as soon as CNN stopped doing hourly updates riddled with crap reporting, improper use of measurements and statistics, and all around unjustified paranoia.

So, what you're really trying to say is that it wasn't that big a deal and Japan has it under control?

 

[STR]

Actually, it wasn't that big of a deal. More people died and more people will get cancer from the two oil refineries that caught fire and burned for a week. The public is incredibly ill-informed on all things pollution. I'd rather live 3 miles away from Fukushima (and been denied the ability to evacuate) than 3 miles from a normally functioning coal-fired power plant.