Could Dawn spacecraft be returned to Earth?

a reply to: wildespace

Yes, Phishy set me straight, see the post above yours. By the way, there have been accidents during launch, and the RTG decay will breach containment one day, wherever the probe is…

could be an impact due to decaying orbit around some moon, or like Voyager, somebody finds it a thousand years from now and the craft is surrounded by a gaseous cloud of PU.

Earth sends greetings…

originally posted by: intrptr
Not a good idea. RTGs are used in deep space to heat and power space craft components. Once activated they become highly radioactive, as does the whole craft.

RTGs and radioactive contamination

From my understanding the radioactive material are insulated individually, then the entire thing is shielded again. The risk is pretty minimal:

To minimize the risk of the radioactive material being released, the fuel is stored in individual modular units with their own heat shielding. They are surrounded by a layer of iridium metal and encased in high-strength graphite blocks. These two materials are corrosion- and heat-resistant. Surrounding the graphite blocks is an aeroshell, designed to protect the entire assembly against the heat of reentering the Earth's atmosphere. The plutonium fuel is also stored in a ceramic form that is heat-resistant, minimising the risk of vaporization and aerosolization. The ceramic is also highly insoluble.

Wikipedia - RTG

a reply to: intrptr

Thanks. I ran the pic through the Deep Dream algorithm app. And now I know for sure, 9/11 was perpetrated by... terrierists.

Luckily, there's research into replacing the more radioactive elements in current RTG types with those having shorter half-lives, and less radioactive elements. Using AM 241 packaged with BE to utilize neutron emission is an excellent idea for a PU replacement. AM 241 does have a long half-life, but it is a much lower activity per gram rate than PU. And it is also solely an Alpha particle emitter. No hard gammas.

a reply to: intrptr

Thanks. I ran the pic through the Deep Dream algorithm app. And now I know for sure, 9/11 was perpetrated by... terrierists.

Luckily, there's research into replacing the more radioactive elements in current RTG types with those having shorter half-lives, and less radioactive elements. Using AM 241 packaged with BE to utilize neutron emission is an excellent idea for a PU replacement. AM 241 does have a long half-life, but it is a much lower activity per gram rate than PU. And it is also solely an Alpha particle emitter. No hard gammas.

I have no idea why my posts kept doubling...

a reply to: pfishy

Thanks. I ran the pic through the Deep Dream algorithm app. And now I know for sure, 9/11 was perpetrated by… terrorists.

That was freakin Hilarious. Thanks for the laugh… (lol, terriorists) gave me a whole new understanding of pareidolia.

a reply to: MystikMushroom

But will eventually decay out of containment, just like the waste storage tanks on Terra Firma.

Nothing more corrosive than alpha emitters. The containment is provided in case of 'mishap' during launch, (i'm surmising).

a reply to: intrptr

Anything for the cause, my friend. Glad you liked it.

And to stay on topic, I'm actually for the prospect of purposely crashing Dawn into Ceres. The final data gathered when we've done this with other probes had been extremely valuable.

originally posted by: pfishy
I have no idea why my posts kept doubling…

If you are experiencing slow loading(?) impatience could cause us to tap the return key twice or refresh/reload the page…

a reply to: intrptr

Well, for launch and obviously to keep it running properly during the mission lifetime. Which particular tanks are you referring to here on our little rock?

originally posted by: pfishy
a reply to: intrptr

I'm actually for the prospect of purposely crashing Dawn into Ceres. The final data gathered when we've done this with other probes had been extremely valuable.

I agree, there isn't enough fuel for a return journey, and the scrap value is negligible. Although there is tons of Gold and other precious metals on earth orbit…

a reply to: intrptr

That's probably it. I have a horrible data connection where I'm currently staying, and the courtesy wifi is even worse.

a reply to: intrptr

There certainly is. Sort of a picker's paradise up there.

a reply to: pfishy

Google search for above top secret threads on leaking tanks…

Gotta go…

originally posted by: Aleister
"Earth" should be funding dozens if not hundreds of new probes a year.

we could you know. now there all sorts of crowd funding and sourcing options and an global communications. what would be needed is a trustworthy organisation with built in and independant auditing. then they could present mission profiles and hardware proposals (rated for viability by experts) and use those to entice donations. they would have to network with govt, universities and industry or inventors.

the big thing wouldn't be getting donations. i don't see that as a problem. the problem is organization and policing the organization's integrity.

a reply to: intrptr

Oh. The Hanford site. Gotcha.

public participation in space is more than just corporations like SpaceX ,Blue Origin and Bigelowe. It's also cube sat programs and even Public relations:

en.wikipedia.org...

In September 2009, three figurines based on the derivative character "Hachune Miku" were launched in a rocket from the United States state of Nevada's Black Rock Desert, though it did not reach outer space.[49][50] In late November 2009, a petition was launched in order to get a custom-made Hatsune Miku aluminium plate (8 cm × 12 cm, 3.1" × 4.7") made that would be used as a balancing weight for the Japanese Venus spacecraft explorer Akatsuki.[51] Started by Hatsune Miku fan Sumio Morioka (also known as "chodenzi-P"), this project has received the backing of Dr. Seiichi Sakamoto of the Japan Aerospace Exploration Agency. On December 22, 2009, the petition exceeded the needed 10,000 signatures necessary to have the plates made. An original deadline of December 20, 2009 had been set to send in the petition, but due to a couple of delays in the Akatsuki project, a new deadline of January 6, 2010 was set; by this deadline, over 14,000 signatures had been received. On May 21, 2010 at 06:58:22 (JST), Akatsuki was launched, having three plates depicting Hatsune Miku and Hachune Miku in several monochrome images, composed of the miniature letters of the messages from the petition form etched in the plates.[52][53]

And the Japanese space probe Habayusa had a public outreach program to get students interested in space science involving a team of students making a cube sat SOMESAT (Social Media Satellite) for launch and to give a special send off the Habayusa Venus Probe. The Video was also made by students with the freeware modeling program MMD.



The Song itself by JimmyThumbi-P was used in at least two other space themed private videos:

Meanwhile at the Japanese verion of Area 51/S-4:




This one has subs for the song lyrics:

a reply to: intrptr

Those rods they store in the heavy water tanks? Unless you swam within a few feet of them you'd be fine. The water acts as a good radiation shield. The more you know...

originally posted by: MystikMushroom
a reply to: intrptr

Those rods they store in the heavy water tanks? Unless you swam within a few feet of them you'd be fine. The water acts as a good radiation shield. The more you know…

Actually, I meant storage of liquid waste from bomb making for instance, like at Hanford and Savannah.

Theres 55 gallon drums dumped off San Fransisco, too. And abandoned reactors from Soviet subs rusting in a Bay somewhere. That kind of containment is far outlasted by the decay of some nuclides and isotopes.

Deep space probes and their RTGs are there forever… so to speak.

Leaky drums off Point Reyes, SF (1990 article)