US: Broken satellite will be shot down

Ah, so the broken satellite was just an elaborate ruse to furthur test the missile defense system without raising international ire! Who said Bush wasn't clever?! Can't let the Chinese one-up America.

Or he could let it fall out of the sky on its own, with no telling where, and YOU might wind up with a nifty new tinfoil h....ead.

Why don't the Americans just come right out and say what all of you are thinking right now! The Russians or Chinese hacked into the guidance or communication system on this piece of sky junk and have been intercepting military communications. The Americans found out somehow and know their expensive POS has been hijacked. They can now justify shooting it down without raising suspicion (LOL ) as a test drone for their new missile system

I see the solar arrays in the picture. The energy dense radar imaging systems used solar arrays as the power source?

Is it really the hydrazine that is of concern or might it be - that since radio communication was never established there was no way to command separation of power pack and that without fractionation of the satellite body the power pack might not burn up?

Is there a nuclear energy source on board the satellite? Why does it even have to be asked? Given past experience with radar surveillance satellite re-entry, particularly the Soviet era Rorsats, isn't this an obvious question? Was that information volunteered or related questions asked? If not why not.

Gavilan

"Given past experience with radar surveillance satellite re-entry, particularly the Soviet era Rorsats"

Didn't an American built Skylab inbed itself into the Australian Desert near Perth in 1979? So I wouldn't throw stones at the Russians. At least if the Yanks blow it up it wont sent another country on alert to expect a reactor to kill anyone by impact or fallout.

I only mentioned the RORSATS because they are the most infamous of accidents involving space applications of RTGs and Reactors. Others have occurred involving US systems. I was not "throwing stones."

The following is speculation. I have a low level of confidence that if what follows is indeed the case, those responsible for our security would fully disclose the potential risks in order to prepare for worst case mitigation.

The satellite causing all the excitement I believe to be a "Radar Imaging Satellite." This means that it has the capability to use high resolution radar to image instead of using CCDs or powerful cameras.

In the past, some "Radar Imaging Satellites" have used RTGs and Reactors to power the radars because of the size and associated problems related to solar arrays for high power applications.

A RTG is a thermocouple device that uses non-fissile decay of a radioactive nuclide to generate heat that is then converted through the use of a thermocouple to generate electrical power. These devices can be fueled by various types of radio-nuclides to include isotopes of 235, 238, 239, or 210.

I am not familiar with the reactor designs used in space applications but conjecture leads me to believe that instead of non-fissile decay, a moderated fissile material is used to generate heat. The significantly higher operating temperature could then be used with thermocouples, or closed loop working fluid generator systems, to produce electrical power. In all "heat engines" the higher the operating temperature (actually the thermal gradient through which the process operates) defines the base efficiency. This is known as the Carnot Cycle Efficiency and encourages the highest possible operating temperatures.

I believe these types of power generation systems could contain anywhere from a few pounds of radio nuclides up to 10s or even hundreds of pounds of material depending on scale.

I consider both RTG and Space Reactor technologies as "mature."

This particular satellite never established initial on orbit radio communication. What this means is, in the case of an accident or normal decay re-entry, the commands to separate the power pack, if it has one on board (which I have no evidence other than the obvious), could not be made to separate the power pack from the satellite as is normally done with RTGs at the life cycle end. The RTG or other type of power pack is then allowed to burn up or is boosted to a burial orbit. This is my understanding (or misunderstanding) of how things were to have supposed to work in the past.

Radio Nuclides are also used as heaters to maintain constant or minimum temperatures in some applications and one satellite may have anywhere from a couple to a couple dozen small heating devices on board depending on sub-systems needs. These types of devices would contain from less than a gram to few grams of material each. Expected materials used would include isotopes of plutonium or other suitable radio nuclide materials.

The reasons I suspect that this satellite may have nuclear materials on board for use in power production or sub-system heaters are:

1. Past precedence.
2. The power required for "Radar Imaging."
3. The fact that these obvious questions and concerns have not been raised.

Regarding the stated concern for the "Hydrazine"; it is a "propellant" used for attitude control and orbital maintenance and maneuvering. It is not nice stuff but I don't think a half a ton of hydrazine would cause this much excitement.

Gavilan

Fair enough.

Good info Gavilan.

Looks like they will shoot it down. And I was making joke.

Brad

Great. How to make lots of small orbital debris instead of a big one...

Great. How to make lots of small orbital debris instead of a big one...

I got the impression that the debris will not stay in orbit -- it will burn as it falls into the atmosphere. The CIA wants to prevent large chunks of classified technology from surviving the fall back to Earth.

I like how in the whole article they don't say "Spy" satelite like in the early reports. Maybe we'll all forget and nobody else will try and grab it first!

The Star Wars Laser system is going to have a publicly publicised tryout, it seems.

Kind Regards....

Continuing to look at the issue:

Aviation Week has stated "The satellite is not nuclear-powered so there should be no risk from radioactive materials, although some spacecraft do carry tiny plutonium-powered heaters, but these would not pose a debris hazard." http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/aw020408p2.xml

End quote.

The above is single source; I have been unable to find any other source that addresses this issue.

I assume that aviation week would not risk a loss in credibility unless there was a high level of confidence in the above statement. How the satellite is powered may be different than how the Radars are powered; but I will accept Aviation Week's inference that there are no isotopes on board used for primary power production. I also believe that any information as to a nuclear power source for powering the radars would be "classified" information. I have not seen this issue addressed in public disclosure by government sources. This causes me some concern.

Regarding that part of the quote referencing "tiny plutonium powered heaters: These heaters would probably be powered by the 86 year half life plutonium isotope. This isotope is extremely hazardous if inhaled or ingested. Even the small amounts in each heater unit would pose significant contamination risk. Although wide dispersal by re-entry burn up would prevent any significant or even measurable increases in background radiation levels, these nuclides would still pose a significant risk if inhaled or ingested. I do not know how oxidation with atmospheric gasses during the re-entry burn up might affect the carcinogenic properties, but in this regard the nuclides of this isotope would be several orders of magnitude more dangerous than the longest half life isotope.

Reactors should not be confused with RTGs. A quick internet search should convince the reader that the planning and design of space reactors for use in earth orbiting radar and weapons applications has been on going for well over 20 years. An example is the SP-100 reactor. I believe it can be safely assumed that there are more advanced designs either in development and most probably, application.

In regards to the recovery of the Nimbus B RTG:

Nimbus B never achieved closed orbital energy and cannot be used as an example of RTG survivability. This can be seen by referencing

http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=NIMBS-B

There have been several publicly disclosed, discovered, or claimed failures of RTG containment upon re-entry; the Peru incident possibly being the most recent.

Another interesting quote from Aviation Week: "The radars can differentiate camouflaged trucks or pack animals in mountainous terrain or under trees. They can also see just fine at night and through clouds. ------Contrary to media reports that say the spacecraft is as large as a school bus weighing up to 20,000 lb., the failed satellite is actually one of the smallest launched in the last several years by the NRO."

Gavilan