 Iridium satellite, constructed entirely from spares and donated by Motorola to the National Air and Space Museum. | |
| SATCAT no. | 25471 |
|---|---|
| Mission duration | 19 years |
| Spacecraft properties | |
| Spacecraft type | Iridium |
| Manufacturer | Motorola |
| Start of mission | |
| Launch date | September 8, 1998, 21:13:00 UTC |
| Rocket | Delta II 7920-10C |
| Launch site | Vandenberg SLC-2W |
| Contractor | Iridium |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Polar Orbit |
| Eccentricity | 0.00145 |
| Periapsis altitude | 520 km |
| Apoapsis altitude | 540 km |
| Inclination | 86° |
| Period | 95 minutes |
| Epoch | 1998-09-08 |
Iridium 77 was a communications satellite which was part of a satellite constellation known as Iridium, named after the 77th chemical element of the periodic table, iridium. It was owned and funded by Iridium, a communications company.
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Transcription
So this is a sample of iridium, now this is a sponge-type iridium so it is very finely divided, very, very light weight. So, we open the vial. Iridium is at the bottom of the group that has cobalt and rhodium, and iridium, like rhodium, can be used in a lot of catalysts. And here we have the glass ampule inside and we can see here that the iridium sample is a sponge. Now again you can see that this is a very, very, very light material and you can see it flowing inside the vial. In fact, iridium catalysts sometimes will work much better than the rhodium catalyst and there is a good example where people have replaced rhodium with iridium and found that they can make much more compound in the same chemical plant and this is really good because then you get more stuff coming out without having to have any more metal work. Chemical engineers have a very nice name for this it is called de-bottlenecking when you get more for the same amount of plant.
Network
Iridium 77 is a part of a space-based communications system called Iridium. Conceived, designed, and built by Motorola, the Iridium system provides wireless, mobile communications through a network of 66 satellites in polar, low-Earth orbits. Inaugurated in November 1998, under the auspices of Iridium LLC, this complex space system allowed callers using hand-held mobile phones and pagers to communicate anywhere in the world—a first in the history of telephony.
Overview
Launch
It was launched by Delta II 7920 from Vandenberg Air Force Base on 8 September 1998 at 21:13:00 UTC[1] along with four other satellites, all of which were Iridium satellites.
Features
Iridium 77 is 3-axis stabilized, with a hydrazine propulsion system. It has 2 solar panels with 1-axis articulation. The system employs L-Band using FDMA/TDMA to provide voice at 4.8 kbit/s and data at 2.4 kbit/s with 16 dB margin. The satellite has 48 spot beams for Earth coverage and uses Ka-Band for crosslinks and ground commanding.[2]
See also
References
- ^ "Iridium 77". nssdc.gsfc.nasa.gov. NASA. August 16, 2013. Retrieved March 30, 2014.
- ^ "Iridium 77". nssdc.gsfc.nasa.gov. NASA. August 16, 2013. Retrieved March 30, 2014.
This page was last edited on 6 February 2024, at 03:16