Data transmission from outer space?

Hi,
OK I know this is a bit of a pipe dream, buuuttt.....
Let's say I was able to launch something with a pod on it, and the pod made it into outer-space, and just kept on a course to say, the moon...
what's my best bet for transmitting data from the pod?
maybe just coordinates... or if possible, photographic data aswell?
I assume radio transmission ...
Thanks for any ideas...op:
-Dave

Microwave spectrum. More specifically USB. Unified S Band.

David

Thank you!
Guess I have alot of reading to do now.

You might want to start at https://www.AMSAT.org to get involved in existing projects before starting your own.


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WillMarchant said:

You might want to start at https://www.AMSAT.org to get involved in existing projects before starting your own.


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Click to expand...

Thanks thats good stuff!

As long as it is a pipe dream, you might want to consider smoke signals.

The receiving antenna is just as important as the transmitter. And it can be heavy as it does not have to go into space

M

Goldstone

WillMarchant said:

You might want to start at https://www.AMSAT.org to get involved in existing projects before starting your own.

Click to expand...

And you can receive hamsat signals from space very cheaply using a $20 USB dongle intended for non-US digital TV reception, a cheap homemade yagi antenna, and fantastic freeware for your PC. One example of many sites dealing with this:

https://ozqube-1.blogspot.com/2014/03/receiving-telemetry-from-satellites-diy.html

How exactly though, do you 'send your coordinates'?? How would a spacecraft work out on its own, without other stations on land/orbit, where it is??

peter.rabbit said:

How exactly though, do you 'send your coordinates'?? How would a spacecraft work out on its own, without other stations on land/orbit, where it is??

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https://www.aprs.org is the ham way of "sending coordinates."

Generally, spacecraft aren't completely autonomous. https://www.qrg.northwestern.edu/projects/vss/docs/navigation/1-how-do-we-know-location.html mentions an exception.



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While there is some information to learn from the hamsat projects, lets keep in mind that the op wasn't talking orbit, but rather a continuous trajectory.

Part of what is needed for the data stream is more information. For instance, do you want continuous reception? Or is it good enough to get reception for say an hour a day? Do you want this year round? Or just part of the year?

If you want continuous reception year round, we are talking spreading your receive stations around the world since the Earth will point you the wrong way for a good chunk of the day. Also, considering you often won't be in an ideal position you will need a very high gain antenna (or array) that can be aimed. And since the distance would constantly increase, your signal level will be constantly decreasing.

1tree said:

While there is some information to learn from the hamsat projects, lets keep in mind that the op wasn't talking orbit, but rather a continuous trajectory.

Part of what is needed for the data stream is more information. For instance, do you want continuous reception? Or is it good enough to get reception for say an hour a day? Do you want this year round? Or just part of the year?

If you want continuous reception year round, we are talking spreading your receive stations around the world since the Earth will point you the wrong way for a good chunk of the day. Also, considering you often won't be in an ideal position you will need a very high gain antenna (or array) that can be aimed. And since the distance would constantly increase, your signal level will be constantly decreasing.

Click to expand...

MClark said:

The receiving antenna is just as important as the transmitter. And it can be heavy as it does not have to go into space

M

Goldstone

Click to expand...

MClark isn't kidding. Considering the transmitter power an amateur would probably have on an interplanetary probe, M is exactly correct. A Goldstone size tracking antenna would most likely be needed.

IIRC a geo bird transmitting SATV to your house with a nominal 100 watt transmitter requires ~0.5 M antenna. Increase the distance by a factor of 10 to lunar distance requires increasing the diameter of the antenna by a factor of 10 or ~ 5m in diameter (signal is 100x weaker so you need an area 100x larger). The amateur satellite would probably have not more than a 1 watt transmitter which is another factor of 100 weaker require another factor of 10 increase in antenna diameter to about 50 meters.

That's not really far fetched, as a 26 meter antenna at Goldstone was used to communicate with Apollo.

Bob

But again, a lot has to do with what hasn't been specified. For instance if the transition is typical,data on an FM signal, or is it morse code on continuos wave? Pick the latter, and the receive gets much easier.

If he was looking to get a CW signal with small amount of data, and only needed to get the data during the daytime during the same portion of the year for launch, a couple yagi antennas, or small dish would get him there for a good long time.

Then again, nothing has been said about the red tape one would need to go through. One would need to deal with the FCC for the radio transition. And one would need to deal with the FAA for the rocket portion. And then there is the antenna location (or perhaps rental) to deal with.

A much easier means would be to contact JPS and find out what it takes to get on to one of their teams. Then you would even get paid for it.


Kirk

Kirk

The OP doesn't understand what is required, what has been done, and what is available, and hasn't invested any of his own time to find out and expects the more knowledgeable folks on TRF to provide with a single simple solution. The bottom line is that there is not one single solution, but each mission has very specific requirements. The only generic comment that can be given is on the required antenna size required to receive a satellite signal from a certain distance, and that is relatively independent of signal mode because the signal are extremely week, and this information was conveyed by MClark and myself.

Low earth orbit communications is not difficult. Amateur radio operators have been doing is for half a century. Consumer geo signal reception has been around for several decades, the most noticeable being consumer satellite TV. Everyone who is not a hermit has seen a satellite TV dish in their neighborhood, and if they desire do so can obtain the signal spec by a simple google search. The same goes for Apollo and communications conducted by NASA on lunar and deep space missions. The required information is readily found by googling.

One can build and launch a cubesat into low earth orbit for as little as $100,000 and all the procedures and protocols are on-line and can be easily found by doing a Google search on "cubesat". This is actually a well established technology and there was an international conference earlier this month in Logan UT with over 1500 participants from 37 countries. The communication protocols are established and standardized and IIRC can even be done through the Internet via an international university based communication link system for a very low cost.

There are currently no propulsion systems for cubesats. I know, I'm in the business and am currently developing several concepts, and without a propulsion system you can't go beyond low earth orbit unless you are willing to spend 10s of millions to develop or purchase a space qualified satellite and propulsion system and obtain a ride into LEO as a secondary payload on a commercial launch. If you can afford this you can purchase all the transmitter you need to do the job.

Again, several google searches will find out what you need to get the job done.

Bob