Satgen 601  Waiting for P3D   by GM4IHJ   (BID SGEN601)   2000-09-30

Whilst reviewing the prospects for newcomers to amateur satellites in
Satgen 599. It was pointed out that the hopefully soon to be launched
P3D satellite, will not be fully operational until the end of 2001.
Apparently this innocent report caused several cases of heart failure
in VK2 and points west. So to clear up any lingering doubts and
eliminate the requirement for still more SPs to all quarters. Here
are the relevant quotes from the minutes of a meeting held in Germany
in April 2000, ( see Amsat Journal July/August 2000 for full report).

"After launch to geostationary transfer ellipse, the apogee will be
raised by ArcJet , through intermittent firings over a period of 270
days. During this 9 month period there will be a period of 4 months
when unfavourable sun angle does not permit firing. Depending on
remaining electrical energy however the satellite will then for the
first time be available to radio amateurs . After 270 days, another 5
or 6 weeks will be needed for additional manoeuvres using the 400N
motor".

(Then), " after extensive tests of the position regulating system and
momentum wheels , the spin mode of P3D will be converted to 3 axis
stabilization" . (Allowing) "Solar panels still wrapped around the
satellite to be unfolded ", (providing) " full electric power to
operate several high power tramsmitters", (together with the use for
the first time of)," high gain earth pointing antennas".

Simple arithmetic therefore suggests that prior to end 2001, only
intermittent, low power budget, use of the satellite through its omni
directional antennas, will be possible.

Clearly a fascinating exercise in orbital ballistics is planned.
Although in the circumstances this is only likely to be observable in
any degree by those radio amateurs interested in orbital mechanics ,
who possess major antenna systems , plus excellent software and
doppler tracking DSP facilities.

But for those who hoped to catch up where they left off with Ao10 and
Ao13, the considerable delay before full operation is available will
be a serious blow. A large section of the amsat fraternity cut their
teeth on 10 and 13, and they can be excused for asking whether this
orbital ballet is really necessary. What is wrong they ask, with a
standard Molniya elliptical orbit provided it is aligned to avoid the
sort of solar and lunar resonances that killed Ao13 ?

Equally the large majority of amsat users , not in possession of
massive antenna arrays and high power after burners, who have waited
patiently up till now for the return of real A010 mid 1980s DX. May
simply give up and go away. As perhaps will IHJs 2 local beginners
who recently , avidly scanned IHJs 80s Ao10 logs in anticipation of
good times arriving shortly. Now they realise their minimal equipment
is going nowhere for at least another year. So while it appears that
we may look forward to a superb orbital experiment. The question left
unanswered is - How many ordinary amsat users will still be around
when that experiment is over?