Michael Koziol reports today in IEEE Spectrum that, despite technical
glitches, SpaceX plans to launch the first of nearly 12,000 Starlink
internet satellites in 2019.
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Originally Posted by Michael Koziol, IEEE Spectrum
But last February, SpaceX launched two small satellites of its own. They were for an initial test of gear intended for use in a globe-spanning broadband data network, called Starlink, made up of thousands of small satellites.
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After launch, Tintin A and B were supposed to propel themselves from their initial orbital altitude of 511 kilometers to their final operational orbit of 1,125 km. But the satellites remained in their initial orbits; SpaceX has never been clear about why. (SpaceX declined to comment for this story.)
“The satellite problems clearly date back quite a number of months,” says Tim Farrar, president of the satellite consulting firm TMF Associates. “The propulsion system is one you check out pretty quick after launch. One of the satellites wasn’t able to move at all. The other one has tried to maneuver without much success.”
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Quote:
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Originally Posted by Michael Koziol, IEEE Spectrum
Outside observers aren’t as optimistic about SpaceX’s chances. There is a consensus that SpaceX’s business model, even more than the technical challenges it faces, could doom the constellation of satellites it plans to deploy. And it’s a big constellation: The U.S. Federal Communications Commission has currently approved SpaceX to launch 4,425 of these communications satellites into low Earth orbit (LEO) and 7,518 more in very low Earth orbit (VLEO), for a total of nearly 12,000 satellites.
According to filings with the FCC, the LEO satellites will broadcast in the Ku (12- to 18-gigahertz) and Ka (26.5- to 40-GHz) spectral bands, which are typical bands for communications satellites. The VLEO satellites, however, will make use of the V band, a higher frequency band ranging from 40 to 75 GHz.
The V band has been used for short, line-of-sight terrestrial applications, because the frequencies are too high to penetrate walls and because moisture in the atmosphere tends to absorb the signal over longer distances. SpaceX and other companies planning LEO and VLEO constellations, including Kepler Communications, LeoSat, and OneWeb, are betting that V band can nevertheless serve as a high-data-rate option for their near-Earth satellites.
An untested spectral band isn’t the only technical hurdle. LEO and VLEO constellations require a radical rethinking of the way satellites communicate with one another and with stations on the ground.
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Story here :-
https://spectrum.ieee.org/aerospace/...rs-not-so-much