Blue Collar Scientist

USS Lake Erie launches a missile at USA 193. See more at the Department of Defense website.

The DoD has a press release stating that at 10:26 PM EST (6:26 Alaska time), the USS Lake Erie fired a missile that hit the errant National Reconnaissance Office satellite known as USA 193. The missile had no warhead, which supports the DoD’s assertion that they are concerned about an intact hydrazine tank re-entry, and not with preventing classified technology falling into unfriendly hands.

The DoD states that confirmation should be available within 24 hours that the hydrazine was released harmlessly in space. This will be apparent from the decay rate of the satellite’s orbit; with about the same surface area, but much less mass, the orbit will decay noticeably more rapidly than if the hydrazine had not been released.

This provides yet another confirmation of the government’s story that amateur observers can make: Assuming that the satellite is largely intact and still visible, in the event the hydrazine has been released, the satellite should show up later, and on a track that is more westerly, than predictions with the current elements indicate. However, there isn’t much time - the bulk of the orbiting material is expected to re-enter within two days. Heavens Above is still providing easy-to-use predictions on the satellite’s visibility.

UPDATE: DoD says that nothing bigger than a football survived - so much for that! Also, I replaced the picture of USA 193’s launch, to a picture of the launch of the missile that hit it, from the DoD website.

I was interviewed a few days ago by a local radio journalist who was asking whether the interception would be visible from southcentral Alaska. My polished and very educational answer was edited down to a succinct “No, it won’t” for airing. The interest seems to have been generated by the occasional visibility of missiles fired from Kodiak Island, but the ships doing this work were too far to the south and west in the Pacific Ocean, and the satellite much too low, for the interception to be visible.

The BBC is reporting that Russia is claiming that the United States’ plans to “shoot down” an uncontrollable spy satellite in a decaying orbit is a cover for “testing of an anti-satellite weapon.”

“Speculations about the danger of the satellite hide preparations for the classical testing of an anti-satellite weapon,” a statement reported by Itar-Tass news agency said.

“Such testing essentially means the creation of a new type of strategic weapons,” it added.

Russia is wrong. Here’s how you can know this.

1. There really is a satellite in this decaying orbit. It is called USA 193, and you can go outside and see it if you want to. Observations have been reported all over the place, there are even pictures to be found, if you go looking, and video of the satellite has been played on the news in the United States, at least. Heavens Above has a page about the satellite that provides information about where the satellite is now, and how its orbit is decaying. As I write, it looks like the satellite just passed south of Anchorage and was probably pretty close to being visible from where I’m sitting.
2. If you can see something in the sky, you can measure its position. And if you can do that, you can calculate its orbit. I used to do this every clear night for asteroids. You take a few pictures, measure the asteroid’s position in each, and then do some computations that result in a description of where that asteroid is in space. Calculating the orbit of an asteroid is pretty hard, but there are freeware software programs that will do all the hard work for you. It turns out there are also similar programs that observers of Earth satellites use. So while the National Space Science Data Center has no real information about USA 193, at least one person has put the observations together and calculated an orbit. Orbits for Earth satellites are described in a standard format, and the numbers, called elements, at this page are in that standard format. They can be taken and plugged into SkyMap Pro or Starry Night or almost any other astronomy software to generate observability predictions for the satellite.
3. More to the point, you can take those elements and see that, indeed, this asteroid is orbiting in a very low orbit, and indeed, it really will decay and deorbit, probably sometime in March, if nothing is done about it.

In other words, this satellite is not a made-up thing. We can go out and look at it, and we know, for sure, certain things about it, and we know this from our own eyes, our own calculations - in other words, we know this by doing things that any reasonably-well informed space enthusiast can do - specialists and government spooks not needed.

Not only is this satellite not made up, but it is obviously not what you’d use to test an antisatellite weapon. If someone wants to shoot down a satellite in a real war, they’re going to go after surveillance or positioning system satellites in low Earth orbit, or communications satellites in very high orbits. If you look at USA 193, its considerably lower than a standard low Earth orbit. And it is losing altitude at a very high rate - not something you will find a useful satellite - a plausible target - doing.

In other words, this whole thing just doesn’t have the profile of a good antisatellite weapons test. Anyone designing a test, who ended up doing this, instead of putting a target into a standard low Earth or geosynchronous orbit, has come up with a very bad model of real-life conditions.

Not only that, but the reasons that the United States is offering for destroying this satellite make sense. The United States government says that there is hydrazine on this satellite, used as a propellant. This is quite plausible - hydrazine is used on hundreds of satellites, including in thrusters for the Space Shuttle, Russia’s own Soyuz manned spacecraft, and aboard the International Space Station.

The problem with hydrazine is twofold:

1. It is very toxic. At quite low concentrations, breathing it causes lung irritation and scarring. At higher concentrations, breathing it causes tremors, convulsions, and death. If it gets in your water and you ingest it, you can add nausea, neurological symptoms, and drowsiness to that list. It’s a carcinogen so it can kill you with a tumor years after exposure. It can damage or destroy your liver and kidneys, and screw up your reproductive organs and cause birth defects.
2. Tanks containing satellite fuel have a fairly high probability of surviving re-entry intact. They have large surface areas compared to their mass, and they can slow down very rapidly and fall to earth without burning up in the atmosphere. If that happens in this case, wherever that tank lands becomes a toxic substances dump, without any of the environmental controls or monitoring that real toxic substances dumps have. If that happens to be my backyard, I’d be really ticked off. (Edit to add: The Bad Astronomer points out that Astroprof has an excellent post about hydrazine, if you want to consult it.)

Oh - don’t believe me that fuel tanks can survive re-entry intact? You don’t have to. There are pictures:

That’s from this NASA page, but if you google this topic, there are dozens of examples you can turn up.

So it seems likely that the reasons given for shooting at this satellite are sound - it is full of a very hazardous substance, and poking some holes in it before it comes down will release that substance into space before re-entry. And that’s what you’d want to do if you had a big tank of hydrazine coming down.

Not only that, but there’s no apparent motive for shooting the satellite down if those tanks aren’t full of hydrazine. Hundreds of classified US satellites have de-orbited in the last few years, and none of them were blown up with an antisatellite missile. The main difference? USA 193 was launched recently, and was never able to be controlled. That means its fuel tanks are pretty full. All the other satellites that de-orbited worked properly, and their fuel was empty, or close to it, when it re-entered. It isn’t plausible that the US wants to blow up the satellite to keep secret technology from falling into enemy hands. Of the thousands of satellites with secret technology that have de-orbited since the space age began fifty years ago, hundreds must have landed in cold-war Russia and other places not friendly to the US. Why weren’t any of them “shot down?”

Besides, a smart engineer designs secret components in such a way that they are sure to destroy themselves in re-entry. (And fuel tanks aren’t secrets.)

Finally, there’s one more clue that Russia is promoting baloney on this issue:

“The decision to destroy the American satellite does not look harmless as they try to claim, especially at a time when the US has been evading negotiations on the limitation of an arms race in outer space,” the statement continued.

That’s right, they have an ulterior motive. They have teamed up with China and are badgering the United States to participate in treaty talks to limit or ban space weapons. Russia wants the United States to look like the bad guy (and maybe the US is - I haven’t really thought through an opinion on whether we should be involved in these talks).

I suppose it is worth pointing out that China has actually blown up satellites in viable orbits with advanced antisatellite weaponry that they acknowledged openly they were testing, and to date, the United States hasn’t - and the Russians are teamed up with China. They just want to take advantage of the circumstance to score political points. Otherwise, why would they say that the United States is “creating a new type of weapon,” when China has already has one?

So, what do I believe? I believe there is a secret satellite in a decaying orbit that has hazardous materials aboard and that the United States is going to punch some holes in the tanks containing the materials, and otherwise break up the satellite so that it falls harmlessly to Earth. I think the notion that we’d have to blow up secret technology on the satellite is insane. I think the Russians are just playing politics with their statement. And I think you should go outside and look at USA 193 so you can say you did!