Work Party At WSC

Last night I returned home after several days in New Mexico.
With a few co-workers, I attended a hardware upgrade party at NASA’s White Sands Complex – which is the earth-based end of the space links for the TDRSS. This fleet of large satellites is parked in orbit at such a distance that they go around the earth at the same speed that the earth rotates – so they appear to stay in the same place. From those lofty perches around the globe they are able to collect data from smaller satellites that orbit much closer to earth, and relay all that data back home.
Of course we are not allowed to take our own pictures, so Google found this one for me.

Dishes in the Desert

Dishes in the Desert


Of primary interest to us is the return-link telemetry stream from the International Space Station (ISS) that passes thru the Tracking and Data Relay Satellites (TDRS), then thru the switches and routers at White Sands, and then by fiber-optic to my office building at MSFC. From there we distribute parts of it to the various international partners, as well as other organizations around the country. The current downlink capability of the ISS/TDRS network is ~150Mbits/sec, nearly continuously around the clock… We are developing plans to take that to ~300Mbits/sec.

There are two ground terminals at WSC and we have equipment at each one. Such a fascinating place, especially if you like high-rate data flows, and high-power RF pumps . . this place is like a fantasy world. Row after row of tall racks with complicated looking stuff, all neat and clean, well-identified, fully redundant, thoroughly documented and configuration managed, tightly scheduled, and highly respected. Such a feeling walking between the rows of humming power supplies, TWT oscillators, and hidden klystrons with unseen shiny waveguide. And then you step outside into the blazing New Mexico sun, and is it eerily quiet – unless the wind is howling. Far from man-made interference, this is truly a special place – ideally suited for this purpose.

I’m not sure what else there is to do out there, and since I don’t feel a need to be at work around the clock – I guess it’s a good thing I like it where I am.

Sure was good to get back home. Still, a very interesting trip.
/;^)

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2 responses to “Work Party At WSC

  1. Mike Wechsler

    Thanks for sharing your time in NM, I especially enjoyed the explanation of how the data is patched thru to the various sites. Is is possible to directly receive the data from the TDRS satellites in Huntsville in case the fiber optic is damaged or cut? Sure would like to see all that RF stuff in their little racks, very impressive I am sure.
    I look forward to hearing more details when I visit you in Huntsville.
    Your description is very colorful, “Row after row of tall racks with complicated looking stuff, all neat and clean, well-identified, fully redundant, thoroughly documented and configuration managed, tightly scheduled, and highly respected. Such a feeling walking between the rows of humming power supplies, TWT oscillators, and hidden klystrons with unseen shiny waveguide.”
    73 Mike

  2. Thanks Mike, I was obviously impressed. I would have stayed an extra day for a tour of the insides of a high power amplifier (HPA). Or up close with the business end of one of big dishes …
    The fiber (actually two, in a ring configuration) is a highly redundant auto-failover kinda thing, and the data flow would actually survive that kind of accident. Even tho the TDRS satellites have dish antennas pointed at New Mexico, one could probably receive some elsewhere – but the entire passband of the downlink is likely a few hundred MegaHertz in the Ku band, and it’d probably be tricky figuring out which slice of the data it was that was actually ours… We would basically have to reproduce much of what happens at WSC. Plus – as ISS orbits the earth, it switches between two TDRS birds, one eastern hemisphere, and another western hemisphere. It is all schedule driven, and it appears auto-magically to us here in Huntsville. I even spotted the ‘alternate-backup’ antenna system for ISS… an AZ/EL mounted array of six VHF cross-yagi type antennas. I offered to haul off any scrap LMR-600 coax they had, but figured I’d have a tough time gettin it on the plane as carry-on baggage. Maybe next time.
    /;^)

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