Hams can help NASA

Hams can help NASA

Chris St. Cyr of the Goddard Space Flight Center says that experienced ham radio operators can participate in the historic STEREO mission to see the far side of the sun by helping NASA capture STEREO's images.

The following is from the press release - NASA Sees the 'Dark Side' of the Sun - at
http://science.nasa.gov/headlines/y2009/23jan_darkside.htm?list157891

St. Cyr notes that experienced ham radio operators can participate in this historic mission by helping NASA capture STEREO's images.

The busy Deep Space Network downloads data from STEREO only three hours a day. That's plenty of time to capture all of the previous day's data, but NASA would like to monitor the transmissions around the clock.

"So we're putting together a 'mini-Deep Space Network' to stay in constant contact with STEREO," says Bill Thompson, director of the STEREO Science Center at Goddard.

The two spacecraft beam their data back to Earth via an X-band radio beacon. Anyone with a 10-meter dish antenna and a suitable receiver can pick up the signals. The data rate is low, 500 bits per second, and it takes 3 to 5 minutes to download a complete image.

So far, the mini-Network includes stations in the United Kingdom, France and Japan—and Thompson is looking for more:

"NASA encourages people with X-band antennas to contact the STEREO team. We would gladly work with them and figure out how they can join our network."








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Hm, a 35' dish in the back yard...who do I know who has one of those....nope. Not a one. Darn the luck. That would be pretty interesting I'll bet.

 

At Gilmore tracking station, just the other side of Fairbanks, they have two 30 meter dishes. One is part of the VLBI network.

Actually, synthetic aperture techniques can work with much SMALLER dishes....to the point where with the right software, standard TV satellite dishes can be used. I'm not sure if STEREO is using synthetic aperture techniques or not. Well worth looking into.

eric

 

KG6WOU. . . . I know where there is one. . . .

 

Personally I took that as a typo - '10 metre' when it should have been '10 GHz'

 

The X band is part of the microwave region of the electromagnetic spectrum. Its frequency range is from 7 to 12.5 GHz. The 10.7-12.5 GHz portion overlaps the Ku band.

73, Carl, AA4MI

 

I wonder if I can get permission to use the 6-7 35' dishes that belonged to the old Nike program. There are about 4 abandoned sites within 10 miles of me, each with 6-7 dishes a piece.

 

Are they implying that the transmitter output and path loss would require a 10m diameter dish to get high enough S/N ratio?

Let me think this through...

If you look at the position of these vehicles...


Vehicle A is about 67 million miles away.
Vehicle B is about 74 million miles away.

The total power consumption of each vehicle is 475 watts, so i'd guess the transmitter is a few watts- assuming 30dB gain parabolic dish.

Using the max theoretical gain for a parabolic dish at 10m diameter in 3cm band(=9.87*D² /λ²)~110,000 times, or roughly 50dB and free space attenuation of 274dB for the path loss over 74M miles...
Tx power of 5W 37dBm
30dB Gain of TX dish 67dBm
274dB path loss -207dBm
50dB 10m dish gain -157dbm
10dB component losses -167dBm

Man. Even with a 10m dish, you'll have a signal strength of -167dBm. And that's if you track this thing across the sky perfectly, and without distorting the dish. You'd need to keep your receiver in liquid nitrogen to keep the noise floor down.

Am I missing something here? Or can you count on your fingers and toes the number of hams around the world equipped to do this.

 

if it's 10 GHZ, then any direcTV or Dish network dish and LNB might work. We just need a 10 GHZ receiver.

but then again, yeah, the noise floor would be HIGH

 

how wide of a beam width would you have with a 10 Ghz 10 meter dish @ 74,000,000 miles? That sat signal must be a Very small drop on a VERY large bucket.

 

DirecTV2 for example, has 240 watt transponders and an 8' parabolic antenna. And it's parked approximately 23,000 miles from our lattitude.

And even with that much power and being relatively close, everyone knows what happens when you lose a few dB from rainshowers.

Stereo is over 3 thousand times further away, moving across the sky with the rotation of the earth, and putting out two orders of magnitude less power (if that much).

I don't even think you can hear it with a 10m dish without a very sophisticated receiver. I'm very curious to see what NASA's expectations are WRT whether they really think Hams are gonna pick this thing up. I wonder if they'll reply to an email... I'm particularly interested in the vehicle's antenna system. That might make all the difference.

 

I am constantly impressed by the outrageously sophisticated radio and antenna systems that some of our fraternity come up with.

It wouldn't surprise me at all to discover that there are several hams around the globe who could take up NASA's request and do a creditable job of it.

I hope that some of them do. NASA was right to give amateur radio operators a 'heads up' about this need. As amateurs, we can all be proud that it occurred to them to do so.

 

I seem to recall one guy who points a 30+ foot dish with a destroyer 5 inch gun mount....

The BIG issue (beyond noise floor) is that at 10 GHz the dish surface may have a maximum deviation of +/- 0.25 inch from perfect to achieve that 50+ dB of gain. That calls for a REALLY good dish -- but certainly not beyond amateur abilities.

This would be a really GREAT experiment for a high school or university ham club! I can just about guarantee that several technology firms would lend both financial and engineering support if approached.

 

Why are the NASA nitwits interested in viewing the far side of the Sun for anyway? What do they expected to find there ... a place to land at night? Do they think it's less bright on the other side than it is on this side?

For heaven's sake NASA, why can't you stop pooping away our tax dollars on this nonsense?

Chuck, AA1MN

 

I think it's to study Coronal Mass Ejections which is basically when the sun has these little nuclear detonations that spit out highly energized matter which has been known to disrupt satcomms, destroy space vehicles, clutter air traffic control radar, cause geomagnetic storms that can indroduce large localised compass errors, and cause power grid disruptions.

It's my understanding that these events can kill astronauts during EVAs.

They have caused widespread blackouts, such as the 1989 blackout that left 6 million without power.

So basically, they're trying to learn enough to be able to predict these things. It would certainly help to know about it before the next magnetic pole reversal because they can deliver lethal amounts of radiation which is currently shielded by our geomagnetic field.

Anything that can knock out ATC, satellites, and our electric grid is a heck of a lot more important that sticking a flag on the moon.