Some flight trackers are reporting those F-22s in the air right now. Good luck to them. The last time someone tried something like this, it didn’t go as expected. This is from an incident involving a large weather balloon in 1998.
At this point, the balloon fiasco has done just about all the diplomatic damage possible. Sec. of State Tony Blinken has delayed his trip to China, the Pentagon is openly using the term “Chinese surveillance balloon” to talk about the passing object, and Republicans are dividing their time between demanding that America haul out everything short of a nuke to bring down this dire threat and droning on about how failing to rain debris across the Midwest makes President Joe Biden look “weak.”
So if someone did get a snapshot from this thing, I hope it was a good one.
At this point, even the most basic facts about the incident are all over the place. Multiple news accounts are describing the balloon as “massive” and describing the platform it carries as “the size of three buses.”
Here’s a quick fact check: The Goodyear blimp is 246' long and about the size of two blue whales. All in, loaded up with fuel, 14 passengers, two pilots, and some game day snacks, the blimp weighs about 20,000 lbs. A good portion of that weight is actually the envelop of the balloon itself, but the 202,700 cubic foot volume of the blimp gives it a lifting capacity of about 13,000 pounds.
That’s a lot. Still, a school bus weighs in at about 25,000 pounds. More if you add all the kids.
So, here’s a simple test: Is the balloon bigger than the Goodyear Blimp? No? Then it’s not going to be lifting a school bus, much less three.
Early estimates of the balloon gave it’s size at a diameter of 40’, which seems reasonable. And when compared to the 6’ size of the standard weather balloons launched each day across the U.S., that’s a pretty darn big balloon. It seems like it could carry a lot.
But there’s another factor. The balloon is reportedly at an altitude over 60,000’. At such an altitude, the air pressure is just 7% of what it is at sea level. A latex balloon at such an altitude is many times larger than it is on the ground. That’s why most weather balloons, by design, pop at an altitude around 70,000 to 80,000 feet. That 60,000 foot altitude is also what made me initially assume this was just a balloon that was underfilled with helium, because when that happens, a balloon doesn’t reach bursting altitude and can drift around for days, just as this one has.
In any case, if the 40’ number is accurate, then this balloon likely had an initial diameter of around 10’ when launched. That gives it an original volume of about 4,200 cubic feet. Helium has a lifting capacity of 0.069 pounds per cubic foot. So the theoretical amount of material the balloon could lift is somewhere below 300 lbs. However, something like 100-200 lbs is more reasonable if the balloon is going to reach and maintain altitude.
Balloon wise, that’s a lot. Most weather balloons carry only a fraction of that load. But then, they’re designed to rise quickly, drift for just a short distance, pop, and drop their instruments back to the ground by parachute.
Assuming the designers of this balloon didn’t much care how fast it got to altitude, and didn’t intend to retrieve the spindly panel of equipment that can be seen below it, 100-200 lbs is probably a reasonable maximum. It’s certainly enough to hold a few solar panels and some instruments.
Notably, Google’s Project Loon, involved balloon with a diameter just under 50’ and a payload of around 100 pounds. That project, now cancelled, was intended to test the use of balloons as internet repeaters, and featured a set of solar panels dangling on a rigid pole below the balloon — which looks very, very much like the images that have been seen of the platform dangling beneath the balloon which originated in China.
And while it’s clear this isn’t the ordinary weather balloon designed to collect temperature, humidity, pressure, and wind speed, larger balloons have routinely been flown to measure everything from high altitude cosmic rays to the amount of aerosols in the upper atmosphere. Nothing about the size or design of this balloon speaks to the idea that it’s designed for surveillance rather than some more benign activity. Google’s Loon balloons were able to better control their position in part because they actually used a complex balloon within a balloon system that allowed finer control over altitude. There’s no sign such a system has been employed in the balloon now drifting into the southeastern U.S.
What seems to be blowing that “just a stray balloon” idea right now is the fact that there are at least two of them. But then, the fact that there are two of them, and that the second one seems to be going over nowhere in particular, could just as easily be taken as evidence that this balloon was not lofted with some military intent. China has claimed these are “private civilian airships,” and while believing the Chinese government on anything is always a bad start, that idea still seems as likely as anything.
Here’s something else. A school bus weighs 25,000 pounds. A typical spy satellite, designed to obtain very high resolution images of the Earth’s surface, weighs 37,000 pounds. China had 62 space launches last year, many of those were military launches. When it comes to floating school buses full of spy gear overhead, China doesn’t need balloons. They have many, highly sophisticated, cameras looking down in the U.S. all the time.
There have been some voices raised noting that balloons, even if they can’t really be steered to an exact location over long distances, can still be raised and lowered in an attempt to alter the path or even linger in an area by using opposing winds at different altitudes. Project Loon did that quite effectively. So they might get close enough to get even better pictures than spy satellites. Which would be a great point … if there was any evidence this balloon was doing anything like lingering in a location or actively altering its course. It’s not. It’s just drifting. NOAA’s Hysplit trajectory model has done a good job predicting the balloon’s path since it was first spotted — or at least as good as anyone can.
The path on this Hysplit model was already about 50 miles south of those projected when the balloon was first spotted, because Hysplit, like any such effort to model behavior across a large section of the atmosphere, is highly subject to large changes resulting from small alterations in early conditions. That cone at the other end of this model is 300 miles wide, and that’s just one day of motion over less than 1,000 miles. It gives some sense of how ridiculous the idea that anyone could release a balloon in central China and steer it to a military base in Montana, without some very obvious control, really is. With the best planning in the world, hitting Montana at all with a drifting balloon, much less a specific location, would involve a huge stroke of luck.
Maybe it is a surveillance balloon. But if it is, the whole premise is foolish in the extreme. Releasing such a balloon was never going to generate useful information, and was certain to generate a serious diplomatic issue.
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