New Horizons Arrives At Ksc Options

[Redstone]

NASA Press Release
APL press release
Space.com Article

Coming up...
October: communications checks
November: hydrazine loading and Atlas V countdown rehearsal
December: integration with Atlas V
January: LAUNCH!

No pictures on the KSC webcams yet.

But still pictures here.


Is that the flight RTG attached to the spacecraft? Or just a dummy?

[RNeuhaus]

I will put anything nuclear information from NH spacecraft here to clear any doubts and any missleading about the nuclear worries:

Designed for Safety
More than 40 years have been invested in the engineering, analysis and testing of RTGs. As described below, safety features of an RTG include the use of a specific type of fuel material, a modular design and construction and the use of multiple physical barriers.

The plutonium dioxide fuel contained in RTGs is a specially formulated fire-resistant
ceramic that is manufactured as pellets to reduce the possibility of fuel dispersion in a
launch or reentry accident. This ceramic form resists dissolution in water and reacts little
with other chemicals. If fractured, the ceramic tends to break into relatively large
particles and chunks that pose fewer hazards than small, microscopic particles.

Multiple layers of protective materials, including iridium capsules and high-strength
graphite blocks, protect and contain the fuel and reduce the chance of release of the
plutonium dioxide. Iridium, a strong, ductile, corrosion-resistant metal with a very high
melting temperature, encases each fuel pellet. Impact shells made of lightweight and highly heat-resistant graphite provide additional protection.

Each RTG contains 18 heat source modules with four plutonium dioxide pellets in each
module. There are two plutonium dioxide pellets in each graphite impact shell, and two
graphite impact shells go into each heat source module. The figure below shows part
of a heat source stack within the RTG.

Risk Assessment and Launch Approval
Any mission that plans to use an RTG as a power source undergoes a safety analysis
carried out by the Department of Energy (DoE). The safety analysis report provides a
comprehensive assessment of the potential consequences of a broad range of possible
launch accidents. In addition to the DOE review, an ad hoc Interagency Nuclear Safety Review Panel (INSRP), which is supported by experts from government, industry and
academia, is established as part of a Presidential nuclear safety launch approval
process to evaluate the safety analysis report prepared by DOE. Based upon the INSRP
evaluation and recommendations by DOE and other Federal agencies, NASA may then
submit a request for nuclear safety launch approval to the White House Office of
Science and Technology Policy (OSTP). The OSTP Director (i.e., the President’s science
adviser) may make the nuclear safety launch decision or refer the matter to the President.
In either case, the launch cannot proceed until nuclear safety launch approval has been
granted.

RTGs can provide continuous power in regions of space where the use of solar power
is not feasible. Over the past 40 years, RTGs have been used safely and reliably on 25
missions, including six Apollo flights to the moon, two Pioneer spacecraft to Jupiter and
Saturn, two Mars Viking landers, two Voyager missions to the outer planets, the
Galileo mission to Jupiter, the Ulysses mission to the Sun’s poles, and the Cassini-
Huygens mission to Saturn.

Long reliability.

Rodolfo

[Guest_Richard Trigaux_*]

The plutonium dioxide fuel contained in RTGs is a specially formulated fire-resistant
ceramic that is manufactured as pellets to reduce the possibility of fuel dispersion in a
launch or reentry accident. This ceramic form resists dissolution in water and reacts little
with other chemicals. If fractured, the ceramic tends to break into relatively large
particles and chunks that pose fewer hazards than small, microscopic particles.

Multiple layers of protective materials, including iridium capsules and high-strength
graphite blocks, protect and contain the fuel and reduce the chance of release of the
plutonium dioxide. Iridium, a strong, ductile, corrosion-resistant metal with a very high
melting temperature, encases each fuel pellet. Impact shells made of lightweight and highly heat-resistant graphite provide additional protection.

Thanks RNeuhaus for your informations.

So it seems that the maximum possible precautions were taken:
-plutonium ceramics cannot disperse in dust., even when broken or exposed to fire
-iridium-graphite casing can withstand the heat of any rocket explosion. (Irridium 2454°C graphite more than 3000°C)
-iridium casing will not rust if fallen in a ocean or place difficult to reach such as a rain-foret.

The policy being, of course, in such a case where a very large risk is involved, to envision the worse case as BEING TO HAPPEN and avoid any nasty effect even in this case. So I suppose that the worse possible accident was envisioned.
The worse case here is a re-entry at more than 11km/s, from a trajectory error in a gravitationnal assistance manoeuver using Earth. In this case the atmospheric braking flame is theoretically hot enough to melt irridium and the ceramics, which would form droplets and eventually dust. But I hope the guies are not dumb and they envisioned this case, where anyway the flame is only during a given time, so that it has other things to grind before reaching the plutonium.

Anyway if a RTG was to fall on the ground, it would be a maximum alert for the local police to avoid ignorant or malevolent people to take away the parts.