Speaking as someone who operates commercial communications satellites, I think one of the bigger negative points of geo is cost. My employer pays approx $200 - $250 Million per satellite to be delivered on orbit. Plus we operate a 24 hour station that employs 25+ people and pay contract support to the manufacturer for each spacecraft we have in geo orbit. That would get a little pricey for an AMSAT project. I do however think we could get a commercial operator to allow us to piggy back a payload on one of their birds if we approached it from that angle. That would allow us to save the expense since they would be flying it anyway.
To answer your question on spacecraft life, most of the satellites our company purchases have a "Contract Life" of 13-15 years. That is they are designed to last 13-15 years minimum, and have enough fuel on board for station keeping that long. They may last longer, they may last shorter. I have seen spacecraft last 18 years (beyond station keeping fuel supply), and I have seen spacecraft catastrophically fail within a few years, or even on boost to orbit. Examples would be spacecraft like AO-40 that catastrophically failed long before it was expected to.
73 DE Mark KK7CU Auke de Jong wrote:
Oops, sorry about the blank message i previously sent...
I just wanted to add my little bit to the geostationary thing: I suppose that going over the stuff already said about the pros and cons, of this new possible venue, some of us seem to be focussed on either the pros or the cons, but just barely failing to see an important larger picture. I prefer to see the issue as comparing it to all the other forms of the larger Amateur Radio community: nothing is for everybody, but as long as people can benefit from it, the interested parties should be encouraged to complete their project. For the unimpressed parties who see the limitations, this won't be the last satellite.
Personally, I will be GLAD to see a HEO(gerstationary or otherwise) satellite FINALLY operable again, and opening-up a range of opportunities beyond line-of-sight for operators who do not posess HF equipment, as well as for those so-restricted for other reasons. The VHF and up bands can get pretty lonely if you live in a remote place... which is something an HF operator might not be familiar with. If there is congestion on the HEO transponder(s), that can only feed the need for additional satellites... I'd rather see sats overutilized, than empty! One benefit I am particularly fond of, is the emergency/priority communications aspect. for the first time EVER, a satellite can be used by amateur class stations located in dire places/situations which will not require active tracking, allowing an antenna system to be set-up and aimed by means of listening for a beacon, and then proceeding to act of communicating without adjustments to the antenna for any amount of time! The communications package that can be used, can be compact-enough to stow, and reliable enough to set up in any situation. As Emergency comms has become somewhat of a cornerstone of Amateur Radio's public image, in addition to it's bargaining power with the bandplanning regulators, The importance of this ability carries implications affecting the hobby as a whole. The large footprint of such a satellite also virtually guarantees an audience when one is needed. I envision a specific section of a linear transponder or other type of transponder provision being dedicated to emergency calling just as CB channel 19 had always been intended. Permanent monitoring of such a system brings yet another benefit to the emergency caller.
I am also curious about the 15-year lifespan mentioned... Would that mean that the spacecraft is expected to fail after about 15 years, or is it expected to last a minimum of 15 years? As we have seen before, certain spacecraft have been known to have useful lifetimes easily doubling 15 years, and 6 times it's own design lifespan!
well, what I thought was going to be a few lines turned out to be a rambling few paragraphs! I can't wait to hear a new satellite whose footprint coverage lasts more than 15 minutes be it geostationary, or Elliptical, or Molniya!
Quoting Michael Tondee [email protected]:
Well unless I've misread or misunderstood something the Eagle payloads would now be put to use in the geostationary orbit. There would be no HEO Eagles. We would have one conventional HEO bird in orbit and that would be P3E. Can someone in the know clarify or is it just to early to
know for sure? 73, Michael, W4HIJ
We should keep SSETI-ESEO's mode U/S transponder in mind.
Could be a bit of a black-belt affair, since the power would be 10w and I don't think they can count on much gain, but still seems to me to be a conventional HEO bird.
In any case, phase IV has been a long-standing dream of AMSAT; it seems we are closer than ever to realizing that dream. It also is a very practical platform for emergency communications, an application that as a group we have wanted to support but to which our current and prospective orbits have frankly not been ideally-suited. Finally, the scarcity of HEO rides has been a dark cloud over two of three up-coming HEO projects worldwide. By negotiating a new source for these, our board is taking important steps in assuring the future of just about any project.
There is some concern that a geostationary HEO will be less fun because it is easier to track. We should remember that the equation that solves for 'fun' has 'experience' as one of its variables. Thus, for a new ham, setting up an s-band dish to point at a geostationary satellite will provide a great deal of challenge and of satisfaction. For the more experienced, the advanced communication package should make a similar offer.
It's amazing to read some of the great ideas spinning off from this opportunity. I imagine my daughter's grade 7 geology class being augmented by a live link with a park ranger in the Canadian North. No other AMSAT project would lend itself well to such a use.
We should seek to make this not only an important part of the amateur emergency toolkit, but also a must-have resource for schools around North America. Just as ARISS offers schools a glimpse into life aboard ISS, a 'Learning on the Edge' program could link students with people in remote locations. It would train and equip people destined for remote locations and would, with local ham help, equip schools to communicate with the people in the field. These adventurers and scientists would make 1/2h contacts with each of the schools in the network, explaining their work and the place they are in.
73, Bruce VE9QRP _______________________________________________ Sent via [email protected] Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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Sent via [email protected] Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb