Monthly Archives: April 2017

Heavens Above Us

My last post noted the increased hand-wringing over the space congestion/debris problem, which is one of the biggest challenges to space situational awareness (SSA). I also defined SSA, using a motorcyclist’s experience to make it more relatable. This post tries to provide some perspective on the debris problem with a little thought experiment.


Sooo much debris. Sooo scary. Image from NASA.

First, orbital debris isn’t something we should put our heads in the sand about. The orbiting used rocket bodies and upper stages, the bits of satellites from accidents and intercept tests, and the disused/abandoned satellites–these do represent a potential problem. Just like polluted water or polluted air, space debris is something we should be cognizant about and try to minimize. But is the human-created space debris situation as bad as some write? You’ve likely encountered some of the posts:

There are a lot of numbers thrown about within these posts meant to depict just how bad the debris problem is. However, the true scope of the problem hasn’t been very well defined. These experts can’t give an accurate number because equipment used to detect debris smaller than 10cm (4 inches) isn’t in use yet. Also, note these estimates keep increasing, which is funny because the initial estimates are just, well, estimates.

Let’s start, then, with researched numbers from decent sources first. The number of “active” satellites on orbit as of December 2016? That number is 1,459, according to the Union of Concerned Scientists’ satellite database. The number of objects with a 10 cm or greater cross-section orbiting the Earth, including active satellites and debris? There are a bit more than 21,000 objects, according to the U.S. military trackers quoted in this post. Satellite speed in a geosynchronous orbit (which is 42,164 km–a little over 26,000 miles–from the Earth’s center)? 3.07 kilometers per second (1.91 miles per second–nearly 6,900 mph). Satellite speed in a low Earth orbit–the kind the space shuttle used? That would be 28,800 kmh (18,000 mph). For these last two bits of information, I used this post: Geostationary orbit: Are satellites faster than the space shuttle?


Orbit image from NASA. Thanks NASA!

Yep, that’s right–satellites in orbits of differing altitudes around the Earth have different speeds.

Let’s put those numbers in context and use something hopefully familiar to many people: the Earth. Let’s consider the Earth’s surface, including its oceans, as a hard-shelled orbit, with an “altitude” from the Earth’s center of 6,378 km (3,963 mi–Satellites helped get us that accurate number). At that altitude, surface orbital speeds are generally between 1,673 kilometers per hour (1,040 mph) and 0, depending on where a person is on the Earth’s surface. One surface orbit has a period of 23 hours, 56 minutes, and 4 seconds.

This means ships, cars, and people, while sitting still on the Earth’s equator, are moving at 1,673 kmh. Unlike satellites, which can be put into many different types of orbits and directions, objects sitting on the Earth’s surface will move in the same direction. There are a lot of “objects” on the Earth’s surface, but collision is never really a problem at this “orbital altitude.” Unless they are an object that moves, like a car or a ship.

Ships, such as tankers and container ships, are useful to help with this perspective. These are behemoths. The biggest container ships carry over 20,000 twenty foot long containers (see this link for one of the biggest). That’s about 20,000 of the biggest satellites ever put into space. That’s just one kind of ship, part of a combined commercial fleet of over 180,000 ships (by the way, that number is getting more accurate, thanks to satellites). These ships are cruising the Earth’s oceans and seas at about the same orbital altitude. Potentially, there are 180,000 very big objects moving around the Earth’s center at a little over 1,600 kmh at an altitude of 6,378 km.

That sounds like a lot of objects, some of the biggest man-made objects around. Yet, if you’ve ever cruised the oceans, you might not see any ship for hours, even though they are basically all orbiting the Earth at the same altitude as you. It’s also, thankfully, relatively rare for collisions to happen with these ships. Compare the number of 180,000 commercial ships to the relatively small number of tracked objects orbiting the Earth–21,000.

Let’s, literally, expand that perspective.

The Earth’s radius is 6,378 km. The Earth’s diameter, then, is twice its radius–12,756 km 97,926 mi). We also know a satellite in geosynchronous orbit is 42,164 km from the Earth’s center or 35,786 km from the Earth’s equator. This means the Earth could fit nearly three times between the Earth’s surface and a geosynchronous orbit point. The diameter of a geosynchronous orbit would be about 7 Earths across.

two point eight

It takes about 2.8 Earth-sized diameters from the Earth’s surface to reach geosynchronous orbit. The 2.8 was eyeballed.

Remember, also, that diameter is just one axis of many possible ones going from one geosynchronous point, through the Earth’s center, to another geosynchronous point. Including debris, 21,000 tracked objects (all much smaller than a commercial ship on Earth) are orbiting the Earth in various altitudes within that volume of space, from low Earth orbit to the geosynchronous belt. That’s a lot of space.

all the earths

Hopefully this post has given some perspective about the spaces on Earth and around it. Don’t worry–we’re not done with the experiment. There’s still a bit more to think about in the next post (or two).


A Motorcycle Rider Defines Space Situational Awareness


There’s been a lot of hand-wringing in recent years regarding space situational awareness (SSA). Almost every month another article appears, portending of the upcoming calamity in space–the point in which one rogue satellite or a chunk of debris hits another satellite or chunk of debris. These two chunks initiate a celestial version of pool. As in pool, one chunk will hit another chunk which speeds on to hit another chunk or cluster of chunks. The struck chunks fan out, hitting other chunks, and then those chunks hit even more chunks, and so on.

Invariably the hand-wringing prompts online conversations about whether this space-snooker-based scenario is realistically depicted in the movie “Gravity” (that Sandra, she floats so gracefully in space). Inevitably, a new round of blog posts use the computer-generated picture showing thousands of pixels surrounding the Earth–with each pixel representing one of the tens of thousands of objects, normally junk, orbiting the Earth.

The resulting picture from these conversations and blog posts is clear–the end is nigh, space-wise. Humanity has once again junked up another environment, and will soon reap what’s been sown. Unless we stop those smaller, less expensive satellites from messing it all up. Or something like that anyway.

According to some people, the number of objects (satellites, debris, rocket bodies, etc.) in orbit is reaching scary levels–tens of thousands–which is why they are verbally wringing their hands for public consumption. Is this a “chicken-littling” of space, or is there really something to worry about here? Is the blame for debris really so clear cut? Before getting to the answer, it’s probably useful to define SSA, particularly for readers new to the space arena.

There are many folks with specific definitions of SSA. The U.S. military is interested in the position, identification, and activities of objects orbiting the Earth which might potentially compromise the U.S. ability to defend itself or carry out global missions. The Europeans encompass some of the U.S. military SSA definition, but include discovering and identifying Near Earth Objects–things in space that might eventually literally have an impact on Earth if they get too close–and space weather.

For this post’s purposes, I will use my motorcycle and traffic survival skills to demonstrate SSA, but if you’re a car driver, you’ve been using aspects of SSA already.

When I first bought my motorcycle, I went through a motorcycle safety class (it’s a useful class–take it if you can). The class imparted one particular acronym that stays with me even now, 17 years later: SIPDE. Each word in the acronym suggests a way to survive on the road and hones great habits for motorcycle riding. S–Scan; I-Identify; P-Predict; D-Decide; E-Execute.

SIPDE reminds a rider to constantly use the tools at hand– eyes, brain, and motor skills-to make a rider aware of what’s happening close by, and then do something to keep the rider safe. Eyes scan for anything that may literally impact the rider. Once a rider’s eyes see something, the rider’s mind identifies it, internally racking and stacking the “threat.”

A rider then predicts what the object may do (a dog or child might run obliviously into the road, a self-righteous cyclist might blow through the stop sign from the left, a truck driver in the rear view mirror is on the phone and might not even see the rider). Once the prediction is made, the rider decides on a course of action, and then does it. This kind of cycle goes on if it’s ingrained in the rider, and it all will take place in seconds.

So, how do motorcycles and SIPDE have anything to do with space?  Essentially the same actions help define SSA, except a satellite takes the place of the rider. The orbit is the “road” the satellite is on. The tools for scanning, instead of a rider’s eyes and brain, are networks radars and telescopes on Earth’s surface–although some nations have a few space-based SSA “eyes” too. The brains are the people and computers trying to make sense of what’s nearby in orbit (is an object at the same altitude, is it on a path to intersect with another satellite’s “road,” etc.).

These people and computers are also attempting to identify objects close to the satellite’s “road”–its orbit (is it the body of a rocket, is it small debris, is it a satellite that seems to be moving from it’s orbit). Once they figure out what an object is, then they must decide whether the object is a threat, and predict possible actions of the object. The people in this SSA network must then decide what to do and then do it. This may be as simple as notifying satellite owners about a possible collision, or just monitoring the same objects to see if anything changes.

But how bad is it really, out there? Exactly how many objects are orbiting the Earth? Again, is this a “chicken-littling” of space, or is there really something to worry about? Is the blame for debris really so clear cut?

The answer, as it always seems to be, is: it depends. That’s where I’ll end it today, but my next post should hopefully give some perspective.

Space, Spring, Snow, Schmoozing, and finally, Snoozing


Setting up New Shepard for launch…Symposium launch, that is.

Wow, what a week!

And yes, the picture above shows Blue Origin’s New Shepard suborbital space launch vehicle being set up.  It’s the same one that launched and then safely landed, five times, near Van Horn, Texas. Really–the real one. The last New Shepard test launch was the most spectacular and you can watch that here, should you wish to. The launch happened around the 51-minute mark in the video below. Blue Origin is entitled to some chest-thumping, I think.

Blue Origin was cool enough to put the vehicle on display in front of the Broadmoor Hotel for nearly a week during Space Symposium this year. A mock-up capsule sat next to it. I’m pretty sure it’s on its way to Seattle to be put on display in a museum there–but that’s just a guess. Wherever it goes, I’m glad I got to see it up close this last week. Here’s my night shot of the rocket. And, yes, the scorch marks are real.


This is a pretty sweet moment for someone who comes from space operations. And this is just the beginning–a beginning that’s been put on hold for decades.

For those of you who don’t know, I work for the Space Foundation, and we just finished hosting the 33rd Annual Space Symposium here in Colorado Springs. It’s a big event for us, and we try to get nearly everyone who has their finger in the space industry pie involved. There aren’t much more than 50 employees in the Space Foundation, so the event is an “all-hands-on-deck” exercise. Education, philanthropic, government, marketing, customer service, museum and research departments all work together towards one goal. Heck, most of the last month was me getting my hands around our Technical Track program.


The Blue Origin capsule. Oddly, there was always a line for this display ;-).

And the Symposium’s success certainly would not be possible if we didn’t have over 300 of the most awesome volunteers in the world helping us. You can meet some of them at our museum, the Discovery Center, here in Colorado Springs.

The Symposium is a big networking event for the global space industry. And people pay a lot of money to network and show off their businesses, which is a little weird to me still. But every person I talked with there seems to like it, so there you go. It’s also pretty neat that so many people from other countries were there: China, Russia, Ukraine, Japan, Germany, Belgium, the Netherlands, and more. So many countries involved in the industry of space, and it’s growing. We can see it growing just because we’re running out of space for the company and agency exhibitors at the Symposium.


Snow and rockets in Spring, in Colorado Springs. Typical for us. Maybe it’s this way in Baikonur, too?

Even some Australians were there, obviously a little jealous of New Zealand’s score of hosting Rocket Lab’s launch pad. Some of them confided in me that New Zealand’s space involvement is probably the best thing to have happened to Australia. I guess the spaceport got someone’s attention, although Australia has had plenty of opportunity to get involved in space for some time.


This is what it looks like behind the stage when a speaker gets a little too verbose…the red light means the speaker has gone over time–in this case one minute and forty-one seconds. It eventually was over 9 minutes…

I tried hard, as the Foundation’s analyst, to talk with anyone I could. It’s what I like doing, especially to help with analysis of the industry. But, and this is not a complaint and just the reality, Symposium duties remain above all during this time. I’ll have to chat with those folks at other events.

So, we had Space Symposium. So what? What’s next? A lot of it depends on the very people who attended the event. Do they intend to follow through on their plans for space? Is everyone’s plan even feasible? If it’s a healthy, open space market, then the answer to that will be “No.” It’s sure going to be interesting, though.

The end of Symposium is always a mixture of sadness and relief for me. I really do love helping with the event–it’s akin to running a mission or a test (but without the heavy consequences if something goes wrong). And I’ve always come alive for those, as I do for Symposium. But at the same time, and I know most of the folks I work with feel the same way, it’s nice to be able to put feet up on the sofa at home, and veg out on Netflix once the event is over. It just takes a lot of energy, at least for me, to not just conduct the event, but talk with people.

One more thing. I discovered it’s pretty great to work with my wife. She was sort of shanghaied to help us at the last minute. But she seemed to like it, and instead of missing her while working 12-18 hour days, I could actually admire the work she was doing. She may have been surprised at all the work we do during this event, but she seemed fine working with us.

I hope I’ll be able to write a bit more now that Symposium is over. Please stay tuned…


Friday–the day after Symposium. Blue Origin’s New Shepard is ready to ship out. And so are we.