Decaying spy sat shoot-down may coincide with Wednesday's lunar eclipse

Two big things will/may happen in space Wednesday. A total lunar eclipse visible over much of the United States that evening, and a possible attempt by the NAVY to shoot down the defunct spy satellite USA193.

“Lacrosse” radar spy satellite, the “old” model that USA193 was to replace.


The “new” but failed USA193 satellite may look similar to this commercial radarsat2

On February 14th, the US military announced that they have plans to shoot the USA193 satellite down with a missile, “to reduce the danger to human beings”. This gives a new twist to the story.

Official sources say there is about 450 kg of hydrazine fuel (a very toxic rocket fuel) on board, and expect 1100 kg (about one ton) of debris of the satellite itself might reach earth’s surface intact.

It occurs to me that the bigger concern might not be hydrazine, but that some sensitive equipment deep inside the bus sized USA193 spy satellite might survive the re-entry, and fall into the wrong hands. The poisonous hydrazine makes a good cover excuse, but I’ll point out there have been other rocket boosters that have come down with hydrazine in them and there was no urgency to intervene then.

From Wikipedia: Hydrazine is highly toxic and dangerously unstable, especially in the anhydrous form. Symptoms of acute exposure to high levels of hydrazine in humans may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, coma, and it can also damage the liver, kidneys, and central nervous system. The liquid is corrosive and may produce dermatitis from skin contact in humans and animals. Effects to the lungs, liver, spleen, and thyroid have been reported in animals chronically exposed to hydrazine via inhalation. Increased incidences of lung, nasal cavity, and liver tumors have been observed in rodents exposed to hydrazine.

The plan is to intercept the satellite using one or more SM-3 intercept missiles fired from naval vessels in the North Pacific. The SM-3 missiles need to be modified for this task as they normally target object at lower altitude on a ballistic trajectory instead of a true orbit.

At left, a launch of an SM-3 from the Navy AEGIS cruiser USS Lake Erie (CG 70) on April 27th, 2007 in first dual missle test of its kind.

On Feb 18th Ted Molczan has drawn attention to a NOTAM, (NOtice To Air Men) issued by the FAA, that might point to a possible ASAT shoot-down attempt on USA-193 on Feb 20th, at 3:30GMT/UTC (Feb 21st by UTC) which would be about 7:30PM Pacific Standard Time Wednesday evening.

Here is the NOTAM:

PHZH   HONOLULU CONTROL FACILITY02/062 (A0038/08) – AIRSPACE CARF NR. 90 ON EVELYN STATIONARY RESERVATION WITHINAN AREA BNDD BY 3145N 17012W 2824N 16642W 2352N 16317W 1909N 16129W 1241N 16129W1239N 16532W 1842N 17057W 2031N 17230W 2703N 17206W SFC-UNL. 21 FEB 02:30 2008UNTIL 21 FEB 05:00 2008. CREATED: 18 FEB 12:51 2008

The NOTAM excludes an area just west of Hawaii over which USA 193 will pass near the time above (see below map, showing USA 193’s approximate position at 7:30 PM PST Wednesday evening, Feb 20th (Feb 21st 3:30 UTC):

(click map to enlarge)

This would put the shoot-down right in the middle of the Wednesday lunar eclipse.

If they do attempt it then, they’ll certainly have a lot of eyes, cameras, and telescopes out with the lunar eclipse, so it will either be a spectacular success (with lots of pictures) or a spectacular failure (with lots of pictures).

(h/t) SatTrackCam Leiden

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Jeff C.
February 19, 2008 9:01 am

Another motive for the the shoot down might be the opportunity to perform a live test of our ASAT capabilities. The hydazine story just doesn’t ring true to me.

February 19, 2008 9:30 am

Now, now. We must maintain our implausible deniability.

February 19, 2008 10:49 am

OK, they probably aren’t shooting it down because of the hydrazine.
But just imagine the embarassment for the U.S. if that hydrazine landed in the middle of a big city in a different country, and made loads of people ill. I agree with what the military said: ‘the regret for not shooting it down could potentially be much greater than the regret for shooting it down.’
Anyway, it should still be cool to watch, if anyone can get some pics. 🙂
CNN’s done a good interactive explainer at:

Burch Seymour
February 19, 2008 2:03 pm

I’m LONG out of that world, but did work on a 80’s era StarWars project and we called things like this ‘TOOs’ – Targets of Oppotunity. It costs big bucks to put a target into orbit, so if something presents itself…. Of course the thing I was working on didn’t destroy anything, just lit it up with a low power laser to test aquisition and tracking.

February 19, 2008 2:16 pm

Didn’t skylab scag a cow?

Jim B
February 19, 2008 5:06 pm

Has anyone even thought about the coolness factor? Come on! They are going to blow up a satellite full of fuel! Is it gonna blow up big enough we could see it? I hope they attach a frag cam to the nose and put it up on youtube.
Nasa wants in the next generation to care about what they’re doing, start blowing more things up.

Burch Seymour
February 20, 2008 7:41 am

Jim B – I see a Mythbusters special episode – Can we shoot down a satellite with a civil-war-era rocket powered by diet Coke and Mentos…. Or perhaps burn it out of orbit by focusing the suns rays using a big-a$$ mirror constructed from AOL software CDs pinched from the local Wal-Mart….
Whaddaya think?

Stan Needham
February 21, 2008 5:02 am

They are going to blow up a satellite full of fuel! Is it gonna blow up big enough we could see it?
They did, and we could. And it didn’t even interfere with a spectacular lunar eclipse — a threefer.

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