Author Topic: How to find ASDS position for upcoming Falcon 9 landing attempts  (Read 1642 times)

Offline Kabloona

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This may be a bit arcane, but after having done this a few times and figured out the vagaries of the FCC online search function, I figured I'd share what I've learned in case others want to search this info out for themselves.

SpaceX must apply to the FCC for a "Special Temporary Authority" (STA) to transmit from the ASDS and support ship during landing attempts. Each mission has its own application and resulting permit from the FCC. And on each apllication, SpaceX must list the geographic coordinates of each transmitter. The ASDS is listed as "BARGE" on the application.

So by searching the FCC "STA" database, we can find approved applications that give the planned ASDS coordinates for upcoming landing attempts.

How To Find It

The FCC website search page is here:

https://apps.fcc.gov/oetcf/els/reports/GenericSearch.cfm

To search:

1. Type the word "Space" into the Applicant Name field. DON'T add an "X" after "Space" because you will not get any results! (The full company name is listed as Space Exploration Technologies, but "Space" will suffice for searching.)

2. Specify a date range in the Received Date Range field.

That's it. Click the "start search" button and you'll get all the SpaceX STA's in that date range.

How To Read It

Each application lists the location of three transmitters: one at the launch site, one on the "BOAT" (support ship), and one on the "BARGE" (ASDS).

Normally the "BOAT" and "BARGE" positions are identical. But be aware that sometimes there are cut-and-paste errors carried over from previous applications. For example, the JCSAT-14 application shows the "BOAT" transmitter position carried over from the CRS-8 application and not updated correctly, while the "BARGE" position has been correctly updated.

Also be aware that the applications sometimes do not mention which flight/mission it pertains to. So a bit of deduction based on expected ASDS position is sometimes needed to figure out which mission it is.
« Last Edit: 04/26/2016 08:02 PM by Kabloona »

Offline dorkmo

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Offline IntoTheVoid

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what is fairing re-radiation?

https://apps.fcc.gov/els/GetAtt.html?id=175092&x=.

I'd guess transponders for locating the fairing from reading that letter.

Offline dorkmo

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https://en.wikipedia.org/wiki/Reradiation
Quote
In telecommunication, the term reradiation has the following meanings:

    Electromagnetic radiation, at the same or different wavelengths, i.e., frequencies, of energy received from an incident wave.
    Undesirable radiation of signals locally generated in a radio receiver. This type of radiation might cause interference or reveal the location of the device.

im still not understanding...

Offline IntoTheVoid

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https://en.wikipedia.org/wiki/Reradiation
Quote
In telecommunication, the term reradiation has the following meanings:

    Electromagnetic radiation, at the same or different wavelengths, i.e., frequencies, of energy received from an incident wave.
    Undesirable radiation of signals locally generated in a radio receiver. This type of radiation might cause interference or reveal the location of the device.

im still not understanding...

https://en.wikipedia.org/wiki/Transponder
Quote
In air navigation or radio frequency identification, a flight transponder is a device that emits an identifying signal in response to an interrogating received signal.
Sometimes a transponder doesn't even have a dedicated power source and uses the power from the received signal for it's responding transmission, such as an RFID tag.

Offline OxCartMark

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what is fairing re-radiation?
Try this semi-guess on and see if it sounds believable to you:

The payload fairing, being carbon fiber, doesn't allow the satellite to communicate with the outside world.  By placing an antenna inside the fairing and another one outside the fairing and connecting them with cable (but no amplifier) some degree of communication can be had between the encapsulated satellite and the outside world other than by umbilicals.  And the word re-radiation would seem to fit that scenario.

Offline Jim

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what is fairing re-radiation?

https://apps.fcc.gov/els/GetAtt.html?id=175092&x=.

Fairing re-radiation is where the spacecraft has a transmitter that is on during launch and ascent and the fairing has a horn and antenna to bring the signal outside the fairing.

Offline Retired Downrange

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From the FCC application site:

Explanation
Please explain in the area below why an STA is necessary:
Pre-launch testing for commercial payload mission, to cover fairing re-rad operations at the pad and stand-alone testing at SpaceXs Payload Processing Facility on Cape Canaveral AFS. Not for flight.

Purpose of Operation
Please explain the purpose of operation:    Pre-launch checkout of TTC links for commercial payload mission, including operation of the fairing re-rad system, prior to flight.

Information
Callsign:   WJ9XHP
Class of Station:   FX
Nature of Service:   Experimental

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