Jeffrey LewisUSA 193 Comes Down

© John Locker

AP’s Eileen Sullivan quotes government officials stating that a US spy satellite “has lost power and could hit the Earth in late February or early March…”

The satellite, which no longer can be controlled, could contain hazardous materials, and it is unknown where on the planet it might come down, they said. The officials spoke on condition of anonymity because the information is classified as secret. It was not clear how long ago the satellite lost power, or under what circumstances.

Speculation among visual satellite observers centers on USA 193 — a US Radarsat that malfunctioned shortly after it was launched in December 2006. (Friend of Wonk Jonathan McDowell has a couple of choice quotes in the New York Times about USA 193.)

Reuters’ Andrea Shalal-Esa had a pretty decent story on USA 193 in March 2007:

The experimental L-21 classified satellite, built for the National Reconnaissance Office (NRO) at a cost of hundreds of millions of dollars, was launched successfully on Dec. 14 but has been out of touch since reaching its low-earth orbit.

Limited data received from the satellite indicated that its on-board computer tried rebooting several times, but those efforts failed, said one official, who is knowledgeable about the program and spoke on condition of anonymity.

John Locker has been watching this sucker steadily lose altitude, posting images of the satellite like the one adorning this post. “193 has come down about 30 km in the last 3 months, so by spring we should be able to get even better resolution,” Locker noted in December 2007, “but it begs the question , will the operators let it continue to fall …”?

For more on NRO’s troubles, I recommend the links my posts FIA joins Misty on SpySat Budget Scaffold, FIA Autopsy and Sayonara, Misty, especially:

  • Jeffrey Richelson (The Satellite Gap, Bulletin of the Atomic Scientists 59:1, January/February 2003 pp. 48-54) predicted a major gap that could develop in our all-weather radar imagery coverage if the FIA Radarsat was delayed, and

The fact that USA 193 is coming down is not a surprise; but it reminds us of the real problems that have plagued NRO for too long now.


  1. Jonathan McDowell (History)

    Jeffrey – how confident are we that it’s a radar sat? I agree it’s plausible, but are there convincing indications/leaks/rumours in that direction?

    I just fielded a Canadian paper wanting to know if it will fall on Canada (I calculate a 4 percent chance, if you are interested..) and posted a short story on my <A HREF=“”>latest.html</A&#062;
    page. Although 2000-5000 kg lumps of dead rocket stage fall out of the sky all the time, I was actually a bit surprised to note that dead payloads that big are fairly rare now (4 in 3 years compared to many in controlled deorbit maneuvers).

  2. Jeffrey Lewis (History)

    I don’t have anything more than I’ve seen in the papers.

    The timing is interesting — John Locker figured the thing would be low enough for high quality viewing by Spring.

  3. Al (History)

    This might be a silly question, but won’t it burn up in the atmosphere?

  4. Fred Stone (History)

    Don’t we have aircraft that are capable of shooting this thing down? Wasn’t the F-15 designed as a “Satellite Killer”? That’s how it was first touted. It was said that it could approach near space and launch missles at low orbit enemy satellites. Just a thought…

  5. Fred Stone (History)

    Here’s what Wikipedia says about the F-15’s satellite killing capacity:”
    Satellite killer

    ASM-135 ASAT test launch.From January 1984 to September 1986, an F-15A was used as a launch platform for five ASM-135 anti-satellite (ASAT) missiles. The F-15A went into a Mach 1.22, 3.8 g climb of 65° and released the ASAT missile at an altitude of 38,100 feet (11.6 km). The F-15A computer was updated to control the zoom-climb and missile release. The third test flight involved a retired communications satellite in a 345 statute mile (555 km) orbit, which was successfully destroyed by sheer kinetic energy. The pilot, USAF Major Wilbert D. “Doug” Pearson, became the only pilot to destroy a satellite.3132

    The ASAT missile was designed to be a standoff anti-satellite weapon, with the F-15A acting as a first stage. The Soviet Union could interpret a U.S. rocket launch with a spy satellite loss, but an F-15 carrying an ASAT would blend in among hundreds of F-15 flights.”

  6. mikado (History)

    Al: the answer is a definite maybe. No doubt it will be damaged by re-entry. The question is: are there big enough pieces to survive all the way to the ground? It’s not an easy question to answer, though past experience tells us that some chunks will indeed reach the ground. It depends a lot on how the satellite was constructed and how it re-enters the atmosphere.

    Satellites are deliberately deorbited all the time. Usually, they’re more-or-less controlled, and targeted to land in the ocean to avoid civilian casualties.

  7. Nick (History)

    RE: Burning up in atmosphere. – The atmosphere is not a magic shield, it’s air, and things burn up due to air friction.

    Some of it will: MLI blankets (the shiney gold stuff on satellites), plastic joints, etc.. The solar panels will certainly rip off, as will any external antennae (SAR panels if its a radar sat).

    However, the BUS (the main body / core) will probably survive in some form, perhaps broken up.

    Although there are some considerations:
    1) Fuel Tank – Probably contains Hydrazine, and may very-well survive to impact. You breath that stuff, you’re toast.
    2. Reaction wheels (used to orient the satellite without thrusters) generally heavy spinning disks (usually about 3 – 4 of em)
    3. Internal ballast weights, usually made of tungsten or stainless steel (usually tungsten)..definetly going to survive.

    You’re not looking at a 5 tonne chunk landing on your car, but if it impacts land, it’ll be scattered over several miles (possibly hundreds depending on where / when it breaks up in the atmosphere). How fast the stuff is going when it hits the earth depends on the density of the chunks falling and their trajectory.

    As for hitting any particular area…it depends completely on the orbit of the satellite, as well as the terminal trajectory as it enters the atmosphere.

    Hope this helps, and I’ve worked in the aerospace industry…working on radar-sats as it happens.

  8. iDude (History)

    Not totally, no.

    These types of satellites are very large and well shielded against space junk since they operate at lower altitudes.

  9. Allen Thomson

    A European satellite observer has posted an informative page on USA-193 here:

    I note that this reentry is not a surprise: a standard orbital decay analysis performed shortly after the failure of USA-193 a year ago showed that it would reenter in 2008.

  10. Lao Tao Ren (History)

    If this is a radar sat, is there a chance that it contains a nuclear battery / reactor?

  11. Dave Dooling (History)

    The target actually was the USAF P78-1 Solwind (solar wind) satellite, which was still operating when shot down.

  12. Allen Thomson

    Some pictures of biggish objects that have fallen out of orbit:

  13. Martin Dirksen (History)

    Very interesting to watch how many answers and comments are filled in for this issue…Compare it with the rates of comments on the far more important other issues at this excellent Blog!
    Sincerley Yours-
    P.S: I admit that i am ( too?) a little bit scared if it will fall down on my hometown, Hamburg…

  14. Brazen

    It could be a concern if it contains hazardous materials, such as a nuclear battery.

    It’s not surprising Canandians would be concerned because they probably remember the Cosmos 954 Soviet Satellite crash:

  15. Lee (History)

    From a policy standpoint, are the problems with our satellite infrastructure the result of investing in ray guns and ASAT tech over the basics?

  16. Steven Dolley (History)

    Wasn’t the F-15 ASAT program cancelled a long time ago? It was tested but never operationally deployed, IIRC.

    Also, how could we credibly call on the PRC or anyone else to curtail their ASAT programs if we deploy and use one, even to shoot down our own satellites purportedly for safety reasons?

    And then there’s the issue of the space junk that would generate.

  17. Nick (History)

    RE: Brazen

    It will not contain a nuclear battery.

    The reason is as follows…- they suck – ..

    Plutonium batteries or “Radioiosotope Thermionic Generators (RTG)” are expensive, heavy, and produce power through the thermal decay of the plutonium core. Kind of like a reverse-peltier effect, where one side of the generator is hot (in contact with the plutonium) and the other side of the generator is cold (in contact with space). This temperature differential produces a flow of electrons, and hence usable power…just not much of it.

    This type of nuclear power sources is only a viable option when the spacecraft is very far away from the sun, or somewhere where the sun is not very bright, both for the required temperature differential and the weight / power tradeoff.

    Since this satellite is orbiting earth, it would be impractical for a satellite to be designed with this sort of power source (RTG), since the solar irradiance at earth is high enough to justify the use of solar panels to power the spacecraft.

    Besides, any and all spacecraft that use a RTG must first submit a pettition to the EPA and hold meetings in the area that it will be launched, so the NIMBY folk can have their say. There was a Mars probe I believe, recently, that has this type of power source, and NASA had to jump through all these hoops. So unless this satellite is packing nukes (which contravenes treaties on the weaponization of space)…you’re not gonna get any nuclear material.

    That is my opinion…again.

    Also…As for shooting down the satellite…Probably not a great idea until it is very very low…thanks to the chinese this past year, we now have a hell of a lot more orbital debris, from a antisatellite weapon test they conducted. I doubt the US will want to deal with the international griping and such. They’ll probably want to maintain the moral ‘high ground’ against the Chinese in such matters…unless of course…it’s gonna land in China!.

  18. Bjorn Townend (History)

    Suggestions that ASAT be deployed are extremely naive. No one wants to use ASAT until it’s absolutely necessary. The reason for this is, as with the Chinese ASAT test last year, the debris cloud left by the destruction of the satellite could damage or destroy other satellites still in operation. If we take out enough satellites we might even deny ourselves access to space, period. Far better to come down and hope it splashes into the Marianas Trench or some place similarly inaccessable.

  19. Antony

    Get the Chinese to shoot it down.
    I’m sure the Chinese would love the opportunity to show off there superiority over the USA

  20. user.hostile (History)

    Nick, is hydrazine really a hazard? It really depends on who you talk to: At CSG in Kourou, French Guiana when pesonnel load the S/C with Hydrazine, they literally wear Major Matt Mason space suits. In Baikonur, Kazakhstan, on the other hand, your standard issue hydrazine protection gear consist of clean room garb, tee shirt and shorts during the summer.

    By the way, is the ballast used to increase the moment of inertia on the S/C? Given the weight constraints we deal with on broadcast GEO’s, that’s just not option. I presume it would be for recon LEO’s to ensure a steady shot over the target…

  21. Muskrat (History)

    I’m wondering whether satellites couldn’t be programmed with some kind of fail-safe mode. Unless the electronics are totally FUBAR, couldn’t you add a routine that says “if the satellite is going down within the next few days (based on GPS-derived orbital calculations), AND IF no coherent commands are recievd from the ground, then take steps to make sure it lands in a predesignated water zone. I know- if the thrusters and atttiude control systems aren’t working there might not be any steps to take. But if this thing is the size of a bus would it be so hard to add a drogue chute or single-use thruster or something that could, once it dropped below a given altitude, allow the on-board systems to pick their landing spot? (Yes, I also realize that it would make the system prone to spoofing, and we wouldn’t want the Chinese sending fake GPS signals to perfectly good satellites during a crisis, but surely there are ways to guard against that.)

  22. John

    In its various forms, hydrazine is toxic, corrosive, explosive and/or carcinogenic, notwithstanding Russian safety procedures.

  23. Mike (History)

    “…could contain hazardous materials…”,

    wow, that took a lot of courage. If you’re going to go to the risk and trouble of leaking information, you could at least do a competent job of it, not sound like a buffoon.

  24. Mike

    Flying speed is more than 16500 miles/hour. I find some info about thos sat at

  25. Dr. TRON (History)

    Most the posts have been by buffoons. Sky lab was bigger and it burnt up.

    Correct on the Solar Panels. There might be a fuel cell on board. Hydrogen Oxygen No Sweat.

    Hydrazine is also used on certain military aircraft as a back up generator fuel. I remember an F-117 making an emergency landing and the pilot had to radio to the ground crew to stand away.

    The ASAT was a Test program and not a deployed product. Besides it requires a SPECIAL stripped down F-15 and one has to have precise timing to launch it into the “basket”.

    Besides is a KH-13 code name “Crystal” (advanced) made by Boeing.

  26. Bill (History)

    Do any of the independant observers know if and when an orbit track is close to KSC? Or is this one only on a polar track?

  27. IASSOS (History)

    OK, there may be some hazardous materials, and possibly some secret technology. My concern, however, is that some heavy thing — say one pound — could drop out of the sky at high velocity — say 200 mph — and hit me on the head. I would like to see some data on the orbital path: is it polar and therefore puts the whole earth at risk? Or is it equatorial?

    Recall the space shuttle that broke up. Fortunately the “particles” that reached the ground did so in uninhabited areas, but the timing difference that saved Dallas and Fort Worth was probably a matter of seconds back at the break-up point.

  28. Allen Thomson

    > I would like to see some data on the orbital path: is it polar and therefore puts the whole earth at risk? Or is it equatorial?

    It’s in a 58.5 degree inclination orbit: most of the inhabited land area of the planet is included.

    Fresh orbital elements just posted on SeeSat-L:

    USA 193
    1 29651U 06057A 08030.26831198 .00084342 00000-0 15698-3 0 06
    2 29651 58.4892 124.4395 0007499 96.9889 263.2062 16.00418844 04

  29. Ron Paget (History)

    The hydrazine may be rocket fuel unsymmetrical dimethylhydrazine (UDMH). It is flammable, carcinogenic and it is easily absorbed into the skin or mucous membranes. You do not want to be around it!

  30. Allen Thomson

    There’s a decent summary of the situation in Aviation Week & Space Technology, though the last paragraph doesn’t note the disconnect between “full” and “hollow.”

  31. Bob Hottenstein (History)

    I think I saw it hit the atmosphere last night going in a northwesterly trajectory. It was about 10:30. Could it be? It was blue, not the usual white of a “falling star”

  32. Fender

    So what countries are in its path?

  33. Allen Thomson (History)

    Good write-up here:

    Note that orbitological analysis strongly indicates that USA-193 was in the intended final orbit when it failed, rather than in an intermediate one.

  34. Earl Wilson (History)

    For those of you who are concerned about objects re-entering from orbit and falling on you – I point you to:
    Chris Peat has posted a real time view of where USA-193 is located on the globe similar to the ISS data that appears there all the time.
    You will either have to register or at least enter your location for more detailed visibility from your location at that site.
    This IMHO is the best all around satellite info site on the Net.

    Earl Wilson Pres. China Lake Astro Soc.

  35. John Locker (History)

    The Heavens Above website
    now has a page dedicted to the demise of USA 193 with live tracking information.

    As soon as I get any further images , possibly towards the end of the month , I will post an update.

    Meanwhile present estimates indicate decay during the first or second week in March.

  36. D. Holford (History)

    The statement that skylab burnt up is erroneous. Some large chunks came down near the city of Perth in Australia. Some were not discovered until much later, despite significant cash rewards offered to finders. I recall a farmer found a titanium tank buried in a field many months after the re-entry.

  37. intelligent anonymous

    Quit guessing people!!! Here’s the Facts

    USA 193 is a large US spy satellite launched by a Delta II rocket on Dec 14, 2006 at Vandenberg AFB California. It has been out of control since shortly after its launch. It will crash during late Feb or early Mar.

    It is contaminated with high amounts of radiation and/or large amounts of a highly toxic fuel known as Hydrazine. Therefore, government agencies are unwilling to use America’s firepower to destroy it in midair because of the resulting widespread contamination. However, if it crashes on foreign soil and the U.S. sends in a Spec-Ops team to retrieve the top secret parts, it could cause an international incident. You can see the latest orbit updates at

  38. Randy L (History)

    Wouldn’t blasting it to smitherines create danger to the ISS and other important satellites by creating many more thousands of pieces of unneeded space junk? …. or would they be able to shoot it down at a low enough altitude before it starts breaking up?
    I doubt they have plans to shoot it down, just wondering how they’d pull it of if they really wanted to.

  39. Harry

    KH-13, huh? Boeing, huh?

    Wrong on both…

  40. mosl (History)

    Hi there…

    German news agency says that US military is thinking over destroying US 193 with a missile launched from a battleship.
    No idea what kinda weapon system it is, but at least a very interesting information. I believe this worn out tincan maybe is less harmless as some may wish to tell us.

    Greetz fromk Germany,

  41. Frank

    Some of you wondered about the asat missile launched by F-15 back in the 80s. That system was tested but never deployed. In any case we have better missiles today that can be launched from surface ships and there is an excellent chance that they can hit this satellite.

    A couple of people suggested the satellite may be radioactive. That’s possible but not too likely. Previous satellites in this series had solar panels. One speculation is that the satellite failed simply because the solar panels failed to deploy shortly after launch.

    Hitting the satellite a few days before re-entry does not create orbital debris because the satellite is very low and is already experiencing significant atmospheric drag. If you break it up into a hundred pieces, you’ve dramatically increased the exposed surface area. Those bits of debris will re-enter within minutes. By contrast, if you do this to a satellite in an orbit twice as high, the debris will stay up for weeks or months (depending on size and mass). Twice as high again and the debris stays up for years. This exponential dependence of time to re-entry on altitude makes a world of difference. Shooting down a satellite that’s on the verge of re-entry will work, and if it’s done correctly (big IF), it will not create an orbital debris problem.

  42. Andrew Foland (History)

    It was noted by “behindthefall” over at emptywheel that according to the Shanker 2/14 NYT article (, the satellite is 5,000 lbs. That is considerably less than other such satellites (ranging from 15-30k). Anyone know what gives?

  43. Nick (History)

    would the Navy missile detonate only upon impact?…can it be exploded remotely should it miss hitting the satellite?

  44. Gabe (History)

    The renew of a cold war now joining is our favorite customer China