by J.C. Goliathan
from CyberSpaceOrbit Website



Wyoming InfraRed Observatory


The author believes the nuclear events reported here to be very unlikely and only remotely possible, but just as an asteroid impact with earth is remotely possible (and widely researched and reported on), the Jupiter impact issue deserves exposure also, because there is compelling evidence to suggest the feasibility of at least a temporary Jupiter ignition.


Given the potential consequences of this, serious research is warranted. The author is a Geographer and Engineer, not a physicist. Further research is needed by more qualified individuals.

The following two excerpts are from recent press releases from NASA and Sky and Telescope Magazine concerning the Galileo Spacecraft:

"The Amalthea encounter was Galileo’s final flyby. The spacecraft has nearly depleted its supply of the propellant needed for pointing its antenna toward Earth and controlling its flight path. While still controllable, it has been put on a course for impact into Jupiter next September. The maneuver prevents the risk of Galileo drifting to an unwanted impact with the moon Europa, where it discovered evidence of a subsurface ocean that is of interest as a possible habitat for extraterrestrial life." 1

"To eliminate any potential that the spacecraft could someday contaminate Europa, a moon that may harbor primitive life, Galileo will be directed to fall into Jupiter's atmosphere on September 21, 2003, when it will plunge into the Equatorial Zone at 48 km per second." [Approx. 107,000 mph] 2

The Galileo Spacecraft is powered by two different means, its thrust propellant, used for trajectory adjustments, and its main power supply for running instruments.


The latter is 238Pu, or Plutonium-238. This 238Pu is what is known as a radioisotope, or radioactive isotope, which becomes physically hot from its own radioactive decay. This heat is converted into electricity by a thermoelectric converter. At time of takeoff the spacecraft contained more than 48 lbs. of Plutonium-238 dioxide fuel within 144 one-inch diameter x 1½ inch long cylindrical pellets.


Each pellet has about 1/3 lb. of plutonium fuel, most of which is plutonium and a small amount being oxygen. In addition, there are some minor amounts of 238Pu for other heater areas. The pellets are divided into two even groups of 72, each group within an RTG (Radioisotope Thermo-electric Generator) of which there are two on the spacecraft.


Each is mounted on a 16-foot boom that extends away from the other instruments to prevent their malfunction. 3

NASA has never before attempted to crash an RTG into a hostile atmosphere. Not everything is known about Jupiter’s composition, pressures, and temperatures.

Table of Elements in the Fuel Cylinders at Time of Galileo’s Takeoff from Earth




Melting Point

Core: Plutonium-238 dioxide (ceramic form)


1183° F

Uranium-234 from alpha decay of Pu


2075° F

Helium-4 gas from alpha decay of Pu



Enclosure: Iridium (cylinder casing)


4435° F

Carbon (floating graphite membrane)


6422° F at top of core

Note: Some of the above elements may now be ionized (missing an electron) due to high levels of radiation near Jupiter that the craft has been exposed to for several years. Also other isotopes of the above elements, including 239Pu are likely present now.


See under "Concerns Among Some Physicists".


Elements present in the Atmosphere of Jupiter

Jupiter is mostly composed of hydrogen and helium, in various gas, liquid, and metallic forms. The inner core may be composed of a somewhat solid rocky material. The average density of Jupiter is much less than that of Earth, but the pressure in the atmosphere of Jupiter, and below it, is intense.


The probe that Galileo launched into the atmosphere relayed data for about an hour. At that point it was overcome by pressure exceeding 23 times that of Earth at sea level at only 125 miles in.


Towards the core of Jupiter it is estimated that the pressure could be millions of times that of Earth at sea level.

"Jupiter's atmosphere consists of about 81 percent hydrogen and 18 percent helium. If Jupiter had been between fifty and a hundred times more massive, it might have evolved into a star rather than a planet. Our solar system could have been a binary star system, meaning that we would have two suns. Besides hydrogen and helium, small amounts of methane, ammonia, phosphorus, water vapor, and various hydrocarbons have been found in Jupiter's atmosphere." 4

"Jupiter has similar relative abundance of hydrogen and helium to the Sun itself. However, its core temperature…is too low a value to trigger nuclear fusion." 5

Concerns Among Some Physicists

The plutonium cylinders in the RTG’s of Galileo may act as Implosion Weapons and a fission to fusion "trigger". (Diagram B)

Implosion Weapon: A weapon in which a quantity of fissionable material, less than a critical mass at ordinary pressure, has its volume suddenly reduced by compression, so that it becomes supercritical, producing a nuclear explosion. 6

Tom Van Flandern’s summary of "Planetary Explosion Mechanisms" states the following:

"Indeed, nuclear fission chain reactions may provide the ignition temperature to set off thermonuclear reactions in stars (analogous to ignition of thermonuclear bombs)." 7

While 238Pu is fissionable, it has been advertised as not fissile, or in others words this would mean it can produce a fission reaction that is difficult to sustain, but a 1962 test proved Pu-238 to be very fissile:

"The Department of Energy is providing additional information related to a 1962 underground nuclear test at the Nevada Test Site that used reactor-grade [Pu-238 and Pu-240] plutonium in the nuclear explosive.



  • A successful test was conducted in 1962, which used reactor-grade plutonium in the nuclear explosive in place of weapon-grade [Pu-239] plutonium.

  • The yield was less than 20 kilotons. Background: This test was conducted to obtain nuclear design information concerning the feasibility of using reactor-grade plutonium as the nuclear explosive material.

  • The test confirmed that reactor-grade plutonium could be used to make a nuclear explosive. This fact was declassified in July 1977. …

In short it would be quite possible for a potential proliferator to make a nuclear explosive from reactor-grade plutonium using a simple design that would be assured of having a yield in the range of one to a few kilotons, and more using an advanced design." 8

The Nuclear Control Institute (NCI) stated that reactor-grade plutonium could be more desirable for a simple bomb because it eliminates the need to use a neutron initiator. 9 In addition to these facts, note the following in a report entitled "Plutonium-238, Use, Origin and Properties":

"If Pu-238 sits in the reactor long enough, it will absorb a neutron and become Pu-239 fuel." 10

Of course, Pu-239 is very fissile and capable of a sustained reaction. In fact, it is the key component of most nuclear bombs.


Since Galileo was launched in 1989, we know that its Pu-238 will have been sitting in the RTG reactors for at least 15 years by September 2003, maybe longer if the fuel cells were created beforehand. In an analysis of whether the fuel cylinders contain fissionable as well as fissile elements, we have to conclude that it is very possible.

It has already been well demonstrated that a fission reaction can be sufficient to ignite a fusion reaction (i.e. the Hydrogen Bomb). A fission reaction generates high enough temperatures (about 35 million degrees Kelvin) to reach the critical point required for a fusion reaction. This, how-ever, does not necessarily mean that a fusion reaction will occur.


The right elements (various isotopes of hydrogen) must be present or created, so it is assumed. We do know that Jupiter is mostly composed of hydrogen, but we are unsure of the details or if fusion and fission reactions would work exactly the same on Jupiter as on Earth. Since we don’t know everything about Jupiter yet, it is hard to predict the effect of Jupiter’s radiation, high pressures, and intense heat on the fuel cylinders at entry into the atmosphere.


However, conventional belief says that Deuterium and Tritium (isotopes of Hydrogen) are necessary to accomplish fusion. Both may be present or created during a reaction within the dense liquid hydrogen of Jupiter.

We do know that implosion is what will occur to the fuel cylinders at some point in the impact. If the final implosion collapse of the cylinders happens suddenly enough, it would simulate an explosive-initiated implosion, the method normally used in a plutonium nuclear bomb.


  1. How far could the craft travel into Jupiter, and how far would the craft have to travel into Jupiter’s atmosphere for a fission implosion to occur?

    The plutonium pellets aboard are protected against unexpected pressures (not Jupiter’s atmospheric pressures though).


    Since the craft will be traveling so fast (107,000+ mph), the pressure will increase suddenly. The upper crust of Jupiter’s atmosphere is gaseous hydrogen and helium about 600 to 700 miles thick (2% of the radius of the planet), followed by a more liquid substance of the two, and much further in, a more metal version (so it is guessed).


    At only 125 miles down the pressure is already 23 bars (Galileo would go from 1/2 bar to 23 bars in 4 seconds). If the craft is traveling at 107,000+ miles/hr, and the pellets (not the craft) last 20 seconds in Jupiter’s hostile atmosphere before imploding, they would have traveled approximately 500-600 miles inward if one accounts for the craft slowing down after entry. This is about the thickness of the more gaseous part of the atmosphere (this is assuming a perpendicular entry).


    At this point, the pressure would be in the thousands of bars because the increase is exponential, not to mention the temperatures generated at this speed would be tremendous. The pressure gradient would be even steeper if the craft were to enter an area of high pressure such as the giant red spot.


    All that is required for fission from implosion to occur is for the final collapse of the graphite/iridium shell around the plutonium to happen quick enough to prevent a fizzle, (a fizzle is a reaction that turns it into a dud). Since there are 144 separate cylinders, there are many chances to achieve a proper implosion and if one proper implosion occurs, it will be a catalyst for other successful ones.

    The heat generated by entry into the atmosphere is most certainly intense enough for all of the elements present to not only reach melting, but also boiling temperatures within several seconds. Needless to say, all sorts of chemical reactions would be possible.


    The fuel cylinders would travel deeper into Jupiter than the rest of the craft because they are designed to withstand intense heat and pressure.


  2. Would Jupiter be able to keep a fusion reaction going? If so, how long?

    It may be that a fusion reaction is not possible because the proper hydrogen isotopes won’t be plentiful enough or conditions will be too chaotic or the fission reaction can’t be sustained long enough.


    I would assume that subsequent fusion reactions could be kept going indefinitely, if conditions are right, or there may be one small explosion that fizzles out shortly thereafter, much like a small comet event.


    Since we don’t know everything about Jupiter’s makeup or the possible reactions of the elements, something completely unexpected may happen. I am still asking questions and getting a wide variety of responses from physicists.


    I phrase the question like this:

    • "Theoretically, what would happen to a lake of dense liquid hydrogen and helium if a fission bomb were detonated inside it, assuming no other significant elements were present above, below, or in the lake?"


    Often, I get the response,

    • "That sounds similar to a hydrogen fusion bomb."


    They usually backtrack when I tell them my true question, because, admittedly, the situation is more complex than that.

    • "What is the amount of Deuterium?...Tritium?... What is the pressure? How controlled is the situation?"…


  3. Is NASA aware of the possibility of a reaction?

    I am sure they have considered it, and I am also suspicious that they might have planned it.


    The reason I say this, is it seems strange that such a weak excuse was given for not sending the craft out to deep space, especially since early in the Galileo mission planning on Earth, they said that a Jupiter impact would not happen.


    Some argue that the craft is caught in Jupiter’s pull now, but with all of the gravity assist tricks available, and still some propellant left, the craft should be able to break free even if they had to use an assist of one of the larger moons. At this moment the craft is making a tremendous loop out into space in order to speed up for the slam into Jupiter.

    It was once rumored that an elite group known as the JASON Group was working on turning Jupiter into a small star. The possibility is intriguing because the name sounds like J-sun or Jupiter-sun. A possible reason for doing this is that making Jupiter a star will create more favorable conditions on Jupiter’s moons for future research (if it doesn’t destroy the moons somehow, it certainly would thaw them out).


    Jupiter and its moons would be like a mini-solar system. Europa may be the big prize, being one of the few bodies in the solar system to have an abundance of water. Europa would be almost balmy with Jupiter as a star and Hoagland’s idea of searching for life under the ice sheet would become much more plausible.


    In addition to this, Mars would receive some solar radiation from a Jupiter-sun when the two were relatively close. Another odd point to mention is the long delay of sending Galileo into Jupiter. Its extended mission was over 3 years ago. The craft was originally scheduled to go in December 31, 1999 and was called off in the last days.


    Did NASA find out something that delayed the entry?


  4. Would a Jupiter-sun affect Earth significantly, and how soon?

    It takes roughly between 35 and 55 minutes for light from Jupiter to reach Earth depending on their relative positions to each other.


    On September 21st the distance will be about 52 minutes. Radiant heat also travels at the speed of light. We would see the impact and feel the radiant heat simultaneously, 52 minutes after the event.


    Based on solar energy formulas Earth would receive about ½ to 1 Joule per second per m2 depending on how far we were from Jupiter (the range is 4.2 to 6.2 AU), which could be enough to change the balance of temperatures on Earth slightly. (the Sun supplies 1370 Joules/second/m2)


    Jupiter would be 1500-2500 times less bright than the Sun as seen from Earth (100 times less in absolute luminosity).

    According to recent research into the speed of gravity propagation, it is measured at millions of times the speed of light. It may be possible to measure minute gravity alterations in an ignition, (such as in the 10% mass cast-off prediction – see "Protostar Theory") that could be detected almost instantly on Earth.


  5. Where will this event be visible from Earth, if it occurs?

    Unless the date and time changes, the craft is impacting Jupiter on September 21, 2003 at about 2:38pm EDT, image reaching earth at 3:30 (Jupiter is visible pre-dawn from Japan to Australia at this time). Early September occurs shortly after the next conjunction of Jupiter-Sun-Earth (when Jupiter is obscured by the Sun), and Jupiter will start to become visible again just before dawn around September 1st.


    Look in the eastern sky, low to the horizon, right under the constellation Leo. The entry of the craft will be completely unnoticeable if no reaction occurs. If Jupiter ignites, however, a tremendous flash or series of flashes would be seen. (the actual impact would have taken place 52 minutes prior due to speed of light lag).


    Jupiter is visible for 1 to 2 hours in the early morning in September, 2003. (See Diagram A) For daytime viewing, Jupiter would only be visible if it ignites (majority of viewers).


    Important: The Shoemaker-Levy comet event created enormous explosions, but no fissionable material was present to cause a nuclear reaction so the explosion temperatures (at max. 7000ºC) were not high enough to cause a fusion reaction (35,000,000ºC required).

Plutonium Facts



  • radioactive transuranium element that is important as an ingredient in nuclear weapons and as fuel for nuclear reactors

  • produced by deuteron bombardment of uranium-238 in a cyclotron

  • also exists in trace quantities in naturally occurring uranium ores

  • 16 known isotopes [one of these is 238Pu, Plutonium’s normal weight is 244]

  • first detected in 1940 by Glenn T. Seaborg, Joseph W. Kennedy, and Arthur C. Wahl 6

Properties of Plutonium

  • Symbol Pu

  • Atomic number 94

  • Atomic weight 244

  • Group in periodic table IIIb

  • Boiling point 5,850° F (3,232° C)

  • Melting point 1,183.1° F (639.5° C)

  • Specific gravity 19.84


Protostar Theory

An important note to ponder: J. Marvin Herndon and V.K. Konovalov in studies independent of each other have proposed that Jupiter, Saturn, and Neptune are already undergoing a thermonuclear process in their cores.


They use the evidence that these planets currently emit much more energy than they absorb, among other telltale signs. 11 12


Konovalov, a Russian physicist, goes as far as to say that these planets, especially Jupiter, have the potential to ignite into stars at any time, and that to avoid the problem of Jupiter’s "reject of matter" disturbing Earth in an untimely ignition, an artificial ignition could be planned when the Earth’s positional orbit is at a tangent to Jupiter in order to minimize the effect of a its mass ejection cast-off. 11


If this theory is correct and Jupiter is ignited on September 21, Earth, despite being in the correct position, would still intercept a not-so-nice ejecta of more than 900 trillion pounds of Jupiter’s hydrogen and helium 13 weeks later, (around mid-to-late December) traveling at maximum 100km/sec and lasting for possibly several days (the lighter mass would arrive earlier). In my off-the-record discussion with Tom Van Flandern, he stated that a volley of this sort would wipe out most life on Earth above ground, a mass-extinction event.

It was very fortunate for NASA, when it was learned that a comet was going to impact Jupiter in July 1994, (Shoemaker-Levy 9), just as the Galileo craft was arriving in the vicinity to record the impact. (What are the odds?! ) I am sure the information was useful in guiding the Galileo probe, which launched from the spacecraft in July 1995 to explore Jupiter’s atmosphere directly, and also may have been useful for planning the spacecraft impact September 2003.

The Galileo spacecraft, launched from space shuttle Atlantis in 1989, has already completed 34 orbits of Jupiter while studying its systems, the small moon of Amalthea being the most recent mission. The 35th and final orbit/mission that few expected will conclude in an impact with Jupiter.

Star: A self-luminous, gaseous, celestial body of great mass which produces energy by means of nuclear fusion reactions, whose shape is usually spheroidal, and whose size may be as small as Earth or as large as Earth’s orbit. 13

"The goal of fusion is in effect, to produce and hold a small star. It is a daunting and tedious research which is considered to be the most advanced in the world." 14


*It is possible that NASA will move the impact day up unannounced as to avoid responsibility, so be watching in Aug/Sep



5 The Henry Holt Guide to Astronomy, David Baker, 1990 USA
6 Compton’s Interactive Encyclopedia, 1999
13 Merriam-Webster’s Collegiate Dictionary – Tenth Edition