Falconsat-1 Pics.  August, 1999

Here are a few pictures of Falconsat-1 as it was being built at the US Air Force Academy in the spring and summer of 1999.

Comm1 Tray:  Two SpaceQuest (SQ) VHF receivers and a splitter.  Simplest tray.  The dark marks resulted from running the tray through a dish washer.  Guess we got a bit carried away with the heat, but it didn't seem to hurt the tray.

This is the Comm2 Tray with two SQ UHF transmitters and their respective 7.5V converters.  SMA's at the top are for IF in and RF out.  Filtered DB25s at the sides are battery power in (on the left) and control and TLM on the right.   Transmitters are mounted on a 1/4" aluminum heat sink which is bonded to the tray.  Trays are cast aluminum.  At full power there was no measurable heating.   These should run nice and cool in space.

Computer and modem tray.  3.3V converter upper left, two channel SQ modem upper right, SQ CPU and RAM disk stack lower right.  Just prior to sticking all the wires down with about a pound of RTV.  All trays are fed battery power and each has its own converter. 

Power Control Unit (PCU).  Just prior to closeout.  Note multiple hacks.   This thing was made to finally work properly about three days before we stacked the trays.  The diodes near the top and bottom left carry solar array inputs and full PCU output.  These got to hot to touch in testing.  At the last minute we made brass strip heat sinks that were epoxyed on top of them and bolted to the standoff support.   Cooled them a great deal.  One of the inductors in the middle carries all output power.  No way to heat sink them.  In TV they got to 75C.  The db25s and 9s carry all connections in and out and take up a lot of board real estate.  Denser connectors would have been nice, especially when fitting this board and others into a tray and trying to get all the cables to fit.

Battery tray closed out.  Single string of 10 SQ NiCads.  No fuse.  Two thermistors that turned out to read 5 degrees apart.  Luckily we don't care that much about bat temp.  White blocks are nylon spacers that keep the batteries in place and off the bottom of the tray.  This tray ended up about 1/4" higher than the cast tray stock so we added 1/4" spacers above it in the stack.  Most massive part of the satellite.  Batteries are thermally isolated from the structure.

Here it is all stacked up with the external cable harnesses in and stuck down.  Note the four sides laid out like flower peddles around the stack.  Payload attach fittings can be seen projecting through the bottom plate.  Transmit hybrid is in the open space below the bottom tray.  Trays from the bottom up are Comm2 (TX) , EPS (power and some TLM), battery (note the space above it because it was to tall), computer (CPU and modem), ADACS (more TLM and CHAWS sensor collection), and Com1 (receivers).  The black box on the left side of the ADACS tray is the magnetometer.  It will be interesting to see what kind of data we get with this buried inside the satellite.  Black rod bolted to the right corner is the torque rod.  This things weighs 10 lbs.  When we turn it on it almost pulls your eye glasses off your face.  Satellite weighs 140 Kg.   This rod does the same thing the bar magnets did on the Microsats.   We can turn it on and off, which opens the possibility of doing some interesting attitude control experiments.  Boxes on the back of each side panel are the CHAWS-LD sensors, one voltage and one current for each side.  CHAWS is Charge Hazard and Wake Shield - Long Duration: Looking at the potential of plasma around the satellite.  Bottom and top plates are 1/4" 7075 aluminum.  The angle brackets up the sides are the same.  Side panels are honeycomb.  Note all the black bolt heads holding the structure together: All grade 8 hardware, and most are into heilcoils.  When we vib'd this thing the sign sweep looked like a solid block of aluminum.

This is the PAF that holds the bird to the top of the JAWSAT structure.  Four reusable fracturing nuts are in the round housings.  The usual springs are captured inside them.  We tested this a couple of times and it makes a hell of a bang when it comes apart.  But it comes apart every time.  The satellite moves away smartly.

A couple of the 1st Class (senior) cadets who worked on software with me helping time the CHAWS samples.  The main computer sends a command to one of the ECs which then starts exercising its ADC to sample all 12 CHAWS sensors 10 times a second.  These data are sent as a KISS packet over a 9k6 serial link to the main computer which puts them into the file system (SSTL) as a record.  All this is run by a housekeeping task under BekTek SCOS.  We tuned the code that ended up burned into the EC E^2 to get that sample rate as close to 10 Hz as possible.  Used a shareware program called COMTAP or PALS to monitor and time stamp the packets being sent over the 9k6 serial link, noted the time intervals, and tuned the sample loop in the EC code.  ChipView was used to run that code till we got it right and burned the E^2.  James Lottspeth (left) did most of the EC code and was very happy when we got the sample rate to .099997 seconds.

At this point I had been without a hair cut for about three months because there was never a barber shop open when I wasn't in the clean room or software lab.  This went on for two more months.  After a couple of days at Kirttland  in shake and bake we got a half day off and I ran to a barber.  On arrival back at the test facility they almost didn't let me in because I didn't look like my ID picture.

Here is the bird all dressed up in thermal tape and being moved to the shipping container.  The crane was a cadet project from an engineering class all have to take.   Specs from Jan King when he was in charge there.  Worked just great.   Could have lifted the satellite and the rocket.  Note the SQ solar clips, four to a side and four on top.  About 35W total.  CHAWS sensors on the sides; voltage on top, current on bottom.  Current sensors have covers over them because the actual sensor is an extremely delicate stainless steel screen.  PAF is attached to the bottom plate and the shipping plate is attached to it.  Note the temporary clean room set up in the middle of a 'Controls' classroom area.  We couldn't get the hoist into the permanent clean room so the bird came out here to apply thermal coating and for final closeout.

The satellite is in this box.  It's wrapped in plastic and shock mounted.   Good thing because the rental truck had no shocks to speak of.  Capt. Dan Miller and I drove that truck 1700 miles: First from the AFA in Colorado Springs to Kirttland AFB in Albuquerque, then after shake and bake to the OSSS facility at Weber Sate U in Ogden, then back to the AFA.  After about an hour in this thing our feet were numb from the floor vibration and we rode with them up on the dash.  This 15' Issisu truck had two modes: Foot on brake = slowing, Gas pedal on the floor = go forward.  It did about 45 up hills on the interstate.  Downhill we got to 65 before it started shaking so much we figured we didn't need to do a vib test.  When we got to Albuquerque and rolled the container onto the dock we confirmed it was air tight - the top was sucked in about three inches from the altitude change.  We ended up parking the truck with the satellite in it overnight only once, in Moab.  We slept OK because we figured none of the famous Moab Slick Rock Kamikaze Jeepers or Bikers would want to off-road in this thing.

And here is Falconsat-1 with all covers removed and mounted on the shake table at AFRL, Kirttland.  The guys there were great to work with.  Note the covers are off the CHAWS current sensors and you can see the grid the screen is mounted on.  Wires on the outside are the transducers for the vib instrumentation.  You can just see the VHF receive whip sticking out the middle of the top.  The guys there were amazed how solid the structure was.  We were glad nothing fell off.  Prof. Emery Reeves was pleased with the printed results of the test.  Dan Miller and I picked it up and shook it just to be sure nothing rattled.

It's now sitting on top of the JAWSAT stack at OSSS awaiting the stack shake and shipment to Vandenberg.  Launch is presently set for mid October, but is slipping.  We are in the middle of training up the first set of cadets who will operate the bird from the AFA ground station.  The idea is they will train the next class, etc.   About 45 cadets each semester will participate either by operating the ground station, doing engineering studies of the TLM and other data, or designing modifications that may be used in future AFA satellites.  These are cadets in the Astrounautics Dept., and while many graduate to fly something with wings, others go on to run big AF satellite or rocket programs, drive operational AF satellites, or become astronauts.

Now, please God, don't let the rocket blow up.

jw