[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Idea for more satellites in short time

Joe Murray, K0VTY, wrote:

>If Amsat builds and operates EXPERIMENTAL satellites , where does a
>common satellite fit into the mission. By common, I refer to copies of
>previous satellites to ensure a communications capability .
>That capability being prime for that satellite, which ensures a proven
>quality a high percent of the time. In deference to a experimental 
>satellite that has no 100 % proven ability.

>I find no problem with experimental satellite building however one 
>could infer from your post that there may be a difference in how 
>satellite design and construction is approached when the word 
>experimental is removed from a Mission statement.

There can be a middle ground between the two. We can put experimental 
communications payloads on common satellite buses. As the poor kids on
the block, we will always be doing "experimental" satellites, trying to 
use what the professionals consider to be useless. But it is a desirable 
and necessary goal to be able to "replenish the constellation" in a timely
manner in order to keep amateur radio in space on a permanent basis and 
to make satellite operation more than an "experimental" part of amateur 
radio. A lot depends on cultivating an excellent relationship with the
launch authorities. Since we fly as secondary payloads it may not be 
possible to have a common satellite design that can fly on any launch 
vehicle on a moments notice. A lot of the design has to do with meeting 
sometimes bizarre constraints imposed on us by the launch vehicle.

"Experimental" does not mean that we have to start from scratch every 
time. We were doing this once before with the Phase 3A, B, C sequence, 
and the low orbit Microsats. There can be incremental improvements and 
technology updates, and there can be experimental payloads like K band 
or digital transponders. One of the reasons that ham radio exists is to 
allow for "experiments". We have the word "experimental" in our mission 
statement in recognition of that.

I am well familiar with the reasons why P3D was designed as it was. We 
know what went wrong with AO-40, if we could build a second one it might 
work this time. But that does not seem to be in the cards. Even the 
professionals often fail on the first try but they learn from their mistakes
and try, try again.

Emily Clarke, w0eec, wrote:

>At first glance evolution would seem to be 2.4, then 3.3, 5.6, 10 and then 
>24. The move from 2.4 to 24GHz initially seems fairly substantial though 
>when you think about it, it's probably no more substantial than going from 
>6 meters to 70cm.  My only concerns about 24 GHz would be availability of 
>parts and path loss.  Given the problem people seem to have with 2.4G and 
>trees it would appear to me that at 24GHz your average pine tree would 
>appear to be a Faraday cage.

I wasn't trying to start a debate over which microwave bands were "next 
in line", all are important. It's just that we have been hearing the 
comment that "those frequencies are too hard for the average ham" ever 
since the day that satellites moved from 2 meters to UHF. I don't suggest 
that everyone run out and get 24 GHz equipment, but so far I think we 
have one or two hams in the USA capable of hearing AO-40 on 24 GHz, and 
it would be a good thing to increase that by a couple factors of ten. 
There is nothing wrong with carrying an "experimental" K band transmitter 
even if only a few will ever hear it, because we need to encourage a few 
hams to push the frontier. The K band transmitter on AO-40 was a very 
small percentage of the mass, volume and cost of that mission.

2.4 GHz can and should become mainstream, perhaps 24 GHz will remain 
experimental but it is important to recognize that ham radio needs these 
frontiers also. 

Dan Schultz N8FGV

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org