Help needed to monitor Forte post-launch 8/29/97 !!

Eric Rosenberg (erosenberg@orbcomm.net)
Thu, 28 Aug 97 11:20:18 est

FORTE (Fast On-orbit Recording of Transient Events). =


The satellite was developed by the Los Alamos National Laboratory and =

Sandia National Laboratories in New Mexico.  Detailed information on =

the satellite can be found at                                =

     http://nis-www.lanl.gov/nis-projects/forte  =

along with Pegasus information =

     at http://www.orbital.com

Forte consists of an advanced radio frequency (RF) impulse detection =

and characterization experiment. Emphasis is on the measurement of =

electromagnetic pulses (EMP), primarily due to lightning, within a =

noise environment dominated by continuous wave (CW) carriers, such as =

TV and FM stations. Optical sensors will augment the RF system in =

characterizing lightning events. A principal goal is to develop a =

comprehensive understanding of the correlation between the optical =

flash and the very high frequency (VHF) emissions from lightning.

The FORT=90 payload consists of three instruments: an RF system, an =

optical system, and an "event classifier". The RF system incorporates =

three broad bandwidth RF receivers covering the frequency range 30-300 =

MHz, a polarization-selective antenna, and high speed waveform =

digitizers. The optical system consists of a coarse imager which is =

based on a NASA/MSFC design and has a 10km X 10km ground resolution =

for lightning flash location (500 frames/sec) and a fast photodetector =

(50k samples/sec) for recording individual light curves. The event =

classifier, based on digital signal processing technology, will =

provide on-orbit characterization of impulsive RF events which have =

satisfied trigger criteria.

The complete FORT=90 project includes a small spacecraft and a satellite =

operations center at Sandia in Albuquerque, New Mexico. The satellite =

will be nadir pointing and three axis stabilized. Body mounted solar =

cells will provide a daily averaged 55 Watts of power. The target =

orbit is 800 km altitude at 65 degrees inclination. Baseline designs =

specify a minimum mission duration of one year, with the capability to =

operate for up to three years.

Herein lies the problem, and where you can help. =


The sole FORTE ground station is in Albuquerque, New Mexico. The =

satellite will be launched from Vandenburg AFB (California) in a =

southeasterly direction.  The result is that the ground station in =

Albuquerque will *not* be able to see the satellite until ~12 hours =

after launch.  =


The researchers at Sandia and colleagues in the Pegasus group at =

Orbital Sciences have asked if it would be possible for those in the =

amateur satellite and 'hearsat' community to monitor the satellite =

within the first 12 hours to verify that it is transmitting.  =


Amateur satellite enthusiasts can consider this a tune-up for future =

mission tracking!

The Forte technical details: =


FORTE UHF beacon: 401.565 MHz
MODULATION: either 256 of 1024 bps bi-phase, max 3db BW: 16KHz
EIRP: about 1 Watt into a 1/4 wave Monopole =


The pre-launch keplerians are based on a Pegasus drop time from the =

L-1011 of 15:00:00 UTC. Note that the epoch is actually 11:17 =

post-drop...this is the separation time at the end of the third stage =

burn of the Pegasus. =


FORTE
1 00001U 99001A   97241.63283565  .00000000  00000-0  00000-0 0    15
2 00001  70.0020 272.5930 0001034 195.6230 331.1350 14.27534500    12

I will post the exact drop time soon after the launch.  All you have =

to do is that Delta to the epoch of the element set, and estimate =

roughly the AOS time and azimuth (this does not, of course, account =

for lower or higher than predicted sma's, off-zero gamma at injection, =

etc. etc., but should be enough for an initial contact).  Plug the =

above into your favorite tracker and you can see the path quite =

clearly.

The path of the first orbit goes over southwestern coast of South =

America, the eastern Coast of Africa, India and Pakistan, Alaska and =

Hawaii.  =


The first five people to accurately report hearing the satellite will =

get their choice of an Orbital or Pegasus T-shirt and Forte Mission =

patch. I am hoping to free up some more mission patches for everyone =

else who submits their findings. We'll post hte results here and on =

the appropriate web pages!

Your report(s) should include your location (plus lat/lon) and =

equipment used; Time of AOS, TCA and LOS; and any other comments to me =

at the email address in the signature. =


Thanks in advance from the Forte and Pegasus teams. =


Eric

---

Eric Rosenberg  W3DQ (ex-WD3Q)
ORBCOMM Global LP
erosenberg@orbcomm.net