Slashdot Mirror
Over A Dozen Satellites From SpaceX's December Launch Can't Be Identified (theverge.com)
In December a SpaceX Falcon 9 rocket deployed 64 satellites into space. But four months later, more than a dozen "have yet to be identified in space," reports the Verge. "We know that they're up there, and where they are, but it's unclear which satellites belong to which satellite operator on the ground...."
"Many of the satellite operators do not know which of these 19 probes are theirs exactly, and the Air Force can't figure it out either." For a good portion of these satellites, it's possible that they have experienced some kind of technical problem, preventing the operators from contacting the spacecraft in orbit. But part of the identification issue stems from the SSO-A "SmallSat Express" mission's structure. This was a rocket ride-share, a type of launch that's become popular in the industry. As satellites grow smaller, operators can pack a bunch of these tiny probes together on larger launch vehicles, sending them into space all at once. But with so many satellites going into orbit at the same time, it can be hard for the Air Force's technology to distinguish the satellites from each other. And that, in turn, can make it hard for satellite operators to decipher which satellites are theirs...
Not knowing the exact location of a spacecraft is a major problem for operators. If they can't communicate with their satellite, the company's orbiting hardware becomes, essentially, space junk. It brings up liability and transparency concerns, too. If an unidentified satellite runs into something else in space, it's hard to know who is to blame...
One problem is that most of the spacecraft on board all look the same. Nearly 50 satellites on the SSO-A launch were modified CubeSats -- a type of standardized satellite that's roughly the size of a cereal box. That means they are all about the same size and have the same general boxy shape. Plus, these tiny satellites are often deployed relatively close together on ride-share launches, one right after the other. The result is a big swarm of nearly identical spacecraft that are difficult to tell apart from the ground below.
"It's possible that some of the owners of the unidentified satellite got in touch with their vehicles recently and just have not informed the Air Force where they are," the article acknowledges. But Jonathan McDowell, an astrophysicist at Harvard and spaceflight tracker, points out to the Verge that five of the 13 satellites launched on an Electron rocket in December are still unidentified -- as are eight of the 72 satellites deployed on a Russian Soyuz rocket in 2017.
And four months after its launch in December, the web site for Trevor Paglen's "Orbital Reflector" art project (deploying a giant reflective balloon that can be seen from Earth) is still giving visitors this discouraging message.
"Due to the large number of satellites aboard #SSOA, the satellite tracking information is taking longer than we originally anticipated..."
"Many of the satellite operators do not know which of these 19 probes are theirs exactly, and the Air Force can't figure it out either." For a good portion of these satellites, it's possible that they have experienced some kind of technical problem, preventing the operators from contacting the spacecraft in orbit. But part of the identification issue stems from the SSO-A "SmallSat Express" mission's structure. This was a rocket ride-share, a type of launch that's become popular in the industry. As satellites grow smaller, operators can pack a bunch of these tiny probes together on larger launch vehicles, sending them into space all at once. But with so many satellites going into orbit at the same time, it can be hard for the Air Force's technology to distinguish the satellites from each other. And that, in turn, can make it hard for satellite operators to decipher which satellites are theirs...
Not knowing the exact location of a spacecraft is a major problem for operators. If they can't communicate with their satellite, the company's orbiting hardware becomes, essentially, space junk. It brings up liability and transparency concerns, too. If an unidentified satellite runs into something else in space, it's hard to know who is to blame...
One problem is that most of the spacecraft on board all look the same. Nearly 50 satellites on the SSO-A launch were modified CubeSats -- a type of standardized satellite that's roughly the size of a cereal box. That means they are all about the same size and have the same general boxy shape. Plus, these tiny satellites are often deployed relatively close together on ride-share launches, one right after the other. The result is a big swarm of nearly identical spacecraft that are difficult to tell apart from the ground below.
"It's possible that some of the owners of the unidentified satellite got in touch with their vehicles recently and just have not informed the Air Force where they are," the article acknowledges. But Jonathan McDowell, an astrophysicist at Harvard and spaceflight tracker, points out to the Verge that five of the 13 satellites launched on an Electron rocket in December are still unidentified -- as are eight of the 72 satellites deployed on a Russian Soyuz rocket in 2017.
And four months after its launch in December, the web site for Trevor Paglen's "Orbital Reflector" art project (deploying a giant reflective balloon that can be seen from Earth) is still giving visitors this discouraging message.
"Due to the large number of satellites aboard #SSOA, the satellite tracking information is taking longer than we originally anticipated..."
The owners of these satellites don't care which one is which in the tracking info, the air force really doesn't either. CubeSats are small, almost anyone can have one launched if you pay a little and follow some simple rules - https://xkcd.com/1992/
Cubsats are primarily used for proving a technology, zero g experiments and sometime measuring something. You send it up, it does its thing, it reports back the results and then it burns up in the atmosphere. As long as I know generally where in the sky it is I don't need to care which one it is. It will be in its little posy of other cubsats that rode the same rocket up and that's good enough.
ADS transponders can be made down to 500 grams. That's half the mass budget for a 1u cubesat. But the smallest transponder I could find has a power output of 130 watts. Typical cubesats have a power budget of about 2 watts for communications, per Wikipedia (and 130 watts is the maker's idea of "low power consumption").
"Because of tumbling and low power range, radio-communications are a challenge. Many CubeSats use an omnidirectional monopole or dipole antenna built with commercial measuring tape."
That's not really gonna fly...