August 8, 2013
We used to have to know things. Now we have smartphones.
Let’s say I’m standing in my backyard on a clear night, and I notice a bright planet about to set in the west, just over the fence. Jupiter or Saturn? With the naked eye it’s hard to tell, at least for me. But point the Google Sky phone app at the mystery dot, and I know in seconds. Jupiter. Thanks.
We should be astonished at such fact-finding power, but we rarely are. Maybe that’s because web- and phone-based tools for identifying what’s in the sky overhead are becoming more common at the same time as they’re getting easier to use. And most of them are free. NASA just released a nifty Interactive Satellite Viewer, for example, that shows you the current positions of its Earth- and space-pointing spacecraft. It’s similar to other online satellite trackers that have been around for a while, but it’s nicely done.
Even cooler are the smartphone apps that use augmented reality to display the positions of satellites wherever and whenever you happen to be looking. These include Sat Tracker for Layar and — even easier — the Satellite AR app created by Analytical Graphics, Inc. (AGI), who maintain a constantly updated database of all the orbiting objects tracked by U.S. Strategic Command. Look up for more than 15 minutes from any dark location at night, and you’ll likely spot the slow, steady track of some satellite crossing the sky overhead. With Satellite AR, you don’t have to guess which satellite it is. A cartoon-like icon will be superimposed on the real thing.
Best of all is the Google Earth version of AGI’s satellite database. Now you see not just the operating satellites, but all the bits of flotsam orbiting with them. Here’s a screen grab from my location in Virginia. Man, is there a lot of junk up there, most of it debris (DEB) from past launches and explosions. Thanks to these handy tools, I can track all of it, and watch the trash float by in real time.
Update: See the first comment below for yet another version that’s even better.
April 11, 2013
You’re going to need a clock. That’s what the National Air and Space Museum wants to get across to visitors with its new permanent exhibit, Time and Navigation, opening tomorrow.
“If you want to know where you are, or if you want to know where you’re going, you need a reliable clock,” said Carlene Stephens, a curator at the National Museum of American History, which houses the Smithsonian’s collection of clocks and contributed to the exhibit. Appropriately, visitors enter the exhibit by walking under a beautiful blue and gold clock, in the “spirit of the early and truly magnificent European clocks,” says exhibit designer Heidi Eitel. She wanted to include the automaton clock that comes to life every quarter hour to tell “the story of when people began sharing time.”
The exhibit takes you through three eras, starting with Navigating at Sea, when sailors first used sextants and star charts to find their way across vast oceans. Though ships have had navigators since the 1600s, it wasn’t until the early 1800s that they had marine chronometers that kept reliable time at sea and allowed navigation with any precision. Galileo’s pendulum clock and an interactive 19th-century ship’s sextant that lets visitors navigate by the stars are highlights.
Next, the exhibit takes flight. Even aviation heros like Charles Lindbergh got lost before Navy Lieutenant Commander P.V.H. Weems developed air navigation techniques. Overhead, visitors can see the Lockheed Vega Winnie Mae, which Wiley Post and famed navigator Harold Gatty flew around the world in 1931 in just eight days — a feat that could not have been accomplished without precise location-determining skills.
In the third and final era, navigation gets three-dimensional as it moves into space. Throughout this section of the exhibit are star charts where Earth becomes just another potential destination on the map. Our education on space navigation starts with the story of NASA’s nine Ranger spacecraft, notorious for their failures to reach the moon, including two that completely missed the mark. But astronauts eventually made it to the surface, and visitors can see the Apollo sextant and space shuttle star tracker here. “When we go back into deep space,” said curator Andrew Johnston, “it’ll be very interesting to see how far we’ve come with navigation.” With the technology available today, the exhibit explains, spacecraft missions in 2012 were 100,000 times more accurate than they were in the 1960s.
Finally, the exhibit shows us how we navigate today. Atomic clocks (one is on view in case you need to set your watch) that keep time to three billionths of a second, GPS satellites that can be accessed from anywhere in the world, and smartphones that crunch all sorts of data have replaced chronometers and sextants and bulky books of charts. In fact, navigation today doesn’t even need people: Stanford’s driverless-car Stanley is also on display. It won DARPA’s 2005 Grand Challenge by navigating an off-road 132-mile race. But proving its necessity in our everyday modern lives, Time and Navigation ends with stories from today — a farmer, a fireman and a student explain how their livelihoods are affected by the technology developed since the first sailor located the North Star.
January 31, 2013
“Disaggregation” is the word you want on your bingo card if you’re following the military satellite business these days. After spending decades focused on aggregation — that is, packing as many capabilities as they can onto one satellite to get the most bang for their buck in a single launch — the military is starting to think about reversing this trend. Disaggregation, then, is sending up less complex systems in smaller packages, but larger quantities. Threats of budget sequestration have allowed supporters, who argue this strategy will cut costs, to really turn up the volume.
Yesterday, the George C. Marshall Institute and the TechAmerica Space Enterprise Council held a panel discussion in Washington, D.C. as a way to turn an idea into a full-blown conversation. The U.S. Air Force has already decided that 2015 is the go or no-go time for disaggregating two important space missions: secure communications (which includes nuclear command and control) and weather forecasting. Representatives from Boeing, Lockheed Martin, and Horizons Strategy Group (a consultant on security technology) spoke on the panel, along with the former director of space policy at the National Security Council.
There are three primary arguments for disaggregation: resiliency, promoting “tech refresh,” and affordability. A constellation of disaggregated satellites would be more resilient because if one was destroyed (by an enemy or otherwise), it would only affect that one system; whereas destruction of one of the current, larger milsats would be a massive blow to a whole host of systems. It would promote a constant refreshing of technology because lead times (and lifetimes) would be much shorter. As Horizons CEO Josh Hartman noted, instead of a satellite taking eight years to build, with a lifetime of up to 25 years — which inevitably saddles users with decades-old tech — a move to small, simple satellites that take only a year or two to build would let designers and engineers stay more current. And the potentially lower cost, meaning lower risk, of these satellites would let the engineers “push the envelope” and take chances on new technology.
Affordability seems like the easiest point to make, and this is hardly the first time someone has argued for smaller, cheaper military satellites. But not everyone agrees. Lockheed’s Marc Berkowitz held the mild dissenter’s seat at the table: “The assertion that disaggregation will save taxpayer money needs to be proven. More platforms means more launches to get them to orbit.” And while losing one small satellite is better than losing one massive satellite, Berkowitz pointed out that enemies might consider the risk for retribution lower for taking one down. Furthermore, the biggest obstacle toward disaggregation right now is simply that there isn’t really a plan for the transition, nor many models that actually analyze the resilience and cost factors. Essentially, supporters are just going by their instincts that smaller and faster is by definition better.
Hartman from Horizons explained that there are steps the military can take now to test some of these theories, most of which involve taking a current spacecraft that needs upgrades or repairs, and instead of fixing it, disaggregating it into smaller replacement satellites. Between now and 2015 the Pentagon can work on creating reliable models, based on these kinds of experiments, before deciding that swarms of smallsats are the way to go.
September 28, 2012
The imminent departure of Europe’s Edoardo Amaldi unmanned cargo ship from the International Space Station (scheduled for 5:46 p.m. U.S. eastern time Friday) reminded us to follow up on our earlier post about Japan’s Kounotori cargo ship.
That vehicle re-entered the atmosphere on September 14, and as promised, onboard cameras caught the disintegration of the pressure vessel as it broke up. Japanese space agency officials are still reviewing the data, but have released preliminary pictures of the debris. These two were taken at an altitude of 70 kilometers (photos courtesy JAXA / IHI Aerospace):
No cameras are onboard Edoardo Amaldi, but the same REBR instrument that flew on the Japanese ship will be collecting data on this breakup.
Kounotori’s departure from the space station caused some tense moments. NASA astronaut Cady Coleman describes the scene in NASA Mission Control after the ship was released from the space station’s robot arm, when it appeared that the schoolbus-size spacecraft was moving backward to collide with the arm. The vehicle had to execute an automatic abort. Astronaut Suni Williams was watching from inside the space station:
[Kounotori] hovered there for a little while, then seemed to want to come back to us – moved ever so slightly toward the ISS instead of drifting away. We release her in a slightly lower orbit than us – which means she should be going faster according to orbital mechanics, which means she should have been moving away, and forward of us. Instead she was drifting back toward us a little. Well, the software in the system detected this as a “safety net/corridor violation” and sent an ABORT command. As a result, she sped away from us at warp speed! It was seriously like a Star Wars film. She flew away so fast that we had a hard time tracking her on the camera. Her name was Kounotori, meaning stork – so maybe she is like one of those heavy birds that take a while to get going, and then flies away at lightning speed.
It all turned out fine in the end. Here’s video of the faster-than-normal getaway. Everything’s moving pretty slowly until about the 4:38 mark, when Kounotori beats a hasty retreat.
September 10, 2012
Shortly after Japan’s Kounotori cargo ship undocks from the space station on Wednesday, ground controllers will fire its rockets to steer the schoolbus-size craft into the atmosphere so that it burns up over the ocean. Normally, the end would come discreetly off camera. This time, we’ll get to watch the fireworks.
In the 55-year history of satellites re-entering the atmosphere, nobody (or at least nobody in the unclassified world) has ever gotten pictures from the satellite’s point of view. For Kounotori’s demise, Japanese investigators have placed a camera-equipped device called i-Ball inside the spacecraft. The spherical i-Ball has two cameras. One will return 10 images from inside Kounotori as it’s breaking up. The second camera will take 40 pictures after the breakup, and the i-Ball will continue on to a splashdown in the ocean.
This Japanese space agency video shows how it’s all supposed to go:
Japan’s i-Ball won’t be the only instrument recording the spacecraft’s breakup. Another experiment package, called REBR (Re-Entry Breakup Recorder), will collect information on temperature and accelerations as Kounotori is torn to pieces during re-entry.
“Getting data off a satellite that’s coming in and breaking apart is a bit of a trick,” says William Ailor of The Aerospace Corporation, principal investigator for REBR, whose team worked on the technology for more than a decade before flying it for the first time on another Kounotori last year. REBR is contained in a copper shell held together by plastic bolts. Once the spacecraft starts to break up, the bolts melt and the instrument package is set free. “The whole vehicle that we’re riding in has to come apart for us to get out at all,” says Ailor. REBR has no cameras, but its data — transmitted to the ground during a five-minute fall to the ocean — will tell scientists about the timing and conditions of the breakup.
Why do they care? Currently, spacecraft operators err on the side of caution when it comes to de-orbiting a satellite at the end of its lifetime. Rather than risk an uncontrolled entry over a populated area, they command the satellite to re-enter slightly early. “If your casualty expectation exceeds 1 in 10,000, you have to put it in the ocean,” says Ailor. The risk of casualties is based on estimates of when a given satellite would break up as its orbit decays. “What we’re trying to do [with REBR] is calibrate the models that make these estimates.” If satellite owners could be less conservative in their estimates, they could leave valuable satellites — say, the Hubble Space Telescope — operating longer in space.
Information on satellite breakup is considered important enough that a commercial venture called Terminal Velocity Aerospace has licensed the technology from The Aerospace Corp. to do routine data collection on future spacecraft. Meanwhile, Ailor is looking forward to i-Ball’s first-time photos. “I hope they succeed,” he says. “That will be really significant in itself.”
Below: In 1984, cameras in Hawaii captured the space shuttle’s external tank breaking up over the ocean. The STS-41C astronauts narrated video of the re-entry during a postflight press conference:
In 2008, the European ATV cargo vehicle was filmed during re-entry:
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