3 ms·
They say they need to use the DSN to do the comms. This is a set of three stations, in the US, in Spain, and in Australia, that has a 70 meter dish each, plus
by mturmon 13y ago
They say they need to use the DSN to do the comms. This is a set of three stations, in the US, in Spain, and in Australia, that has a 70 meter dish each, plus some 34 meter dishes.
Here is a pic of the 70 meter dish:
http://deepspace.jpl.nasa.gov/dsn/images/picture_70_bw_lg.jpg http://deepspace.jpl.nasa.gov/dsn/images/picture_70_bw_lg.jp...
It's not regular ham equipment in many ways, obviously. Besides power, aperture, and accurate pointing, which have been mentioned here, there is also the need to hand off transmitting/receiving as the Earth rotates. You also need a receiver and transmitter velocity model to adjust for Doppler.
People are not giving the difficulty of this problem adequate respect.
- Aloha 13y agoHow hard would it be for access to be granted to the DSN? The challenge to build the transmission equipment does not seem insurmountable nor even particularly hard. It's the logistics and red tape to make it happen. I'd also like to point out, that this satilite will be doing a near earth flyby - you could probably get away with something smaller, maybe even a 3.5m dish versus a you know, 70m dish.
- mturmon 13y agoThe engineers at GSFC say you will need the DSN. The smallest DSN antenna is 26m and that is used only for LEO (a couple thousand km). You talk about "red tape" like moving a huge radio telescope is some kind of formality, and you quoted a figure of 3.5m with no apparent engineering basis. I find this ridiculous.
- Aloha 13y agoThe red tape isnt moving the dish - its getting someone to agree to let them mount a feedhorn for the proper band, and the needed radio hardware. Moving the dish to me seems like the least difficult part, as it pales in the complexity to mounting the hardware. For what its worth both Voyager probes feature S-Band Antennas - I have trouble believing we cant talk to those either on S-Band.
- sp332 13y agoThere are lots of other issues involved, but the DSN picked up the carrier signal in 2008, and it's much closer now. The article also mentioned that people can listen to the carrier as it goes by. I don't think dish size is one of the problems.
- Aloha 13y agowell, other than 0db gain antenna on the sat. But, ideally, if we can hear it, all we need to do its match the equivalent ERP on this end that the sat is sending (gain of the TX antenna on the sat, plus the minimum gain of the RX antenna required to successfully receive) it should work.