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External ISS Experiment in the Amateur Satellite Service
US Naval Academy Satellite Lab
Bob Bruninga, WB4APR, Principal Investigator
Midshipmen Otero, Silver, Jones, Kolwicz, Evans, and Henry (Class of 03)

# Launch on Space Shuttle is slated for the first return-to-space 
mission.(Mar 2005)
# All Final flight testing is complete.
# Completed Astronaut EVA deployment training at NRL on 19 Aug 2004.
# She is ready for shipment to the Cape for Launch
# Thermal-Vac completed on 17 Dec. Download .XLS spread sheets. The only 
apparent temperature dependencies were about 180 mA delta in Iload and 
Ibat and about 5 mA on RXB as shown on the last two current plots.
# Flight integration at NRL began in Sept 2003

PCSAT2/MISSE5/PEC: MISSE is a Materials International Space Station 
Experiment using a Passive Experiment Container (PEC) to fly space 
environment samples to space and back. It has flown 4 times including a 
year on MIR as MEEP. It is attached to the exterior of the ISS during an 
EVA to expose its samples to space. For MISSE5, these samples are 
high-tech DOD solar cells on the side of MISSE that faces the sun. On 
the back side, the Naval Academy has an opportunity to add an Amateur 
Satellite Communications system similar to what it is flying on PCsat as 
an external ARISS payload. It will support educational and student 
outreach objectives of both AMSAT, ARRL and NASA.

The PCSAT2comm system will operate in the ITU Amateur Satellite Service 
in cooperation with ARISS and provide a PSK-31 multi-user transponder, 
an FM voice repeater for possible use with ISS Crew communications and 
an AX.25 packet system for use as a UI digipeater and for telemetry, 
command, control as shown in the block diagram. The PEC is basically a 
suitcase for travel that opens in space as shown above. The solar panel 
side of the PEC will contain new technology solar cells and the 
housekeeping telemetry from PCSAT2 will include data on the techincal 
investigation of the radiation effects on these cells. See the Paper on 
PCSAT2's operation in the Amateur Satellite Service or the Full ITU 
rules as published by the IARU .

See P6 mounting location photo
See P6 closer photo
See PEC drawing deployed
Location considered on Airlock.

This image below is the current (Aug 2004) intended mounting location..

SPONSORING ORGANIZATION: The Telemetry/Command/Communications project 
called PCSAT2 will be conducted under the USNA Small Satellite program 
with the guidance of LTCL Billy Smith and Satellite Lab Senior Research 
Engineer, Bob Bruninga, WB4APR. The USNA Amateur Radio Club would be the 
spacecraft operating organization. Since PCSAT2 will fly on the ISS, its 
operations will be fully coordinated with the ARISS (Amateur Radio on 
the ISS) international team.

PCSAT2 DESCRIPTION: PCSAT2 will use the same dual redundant AX.25 
command and control system as used on PCsat (NO-44) offering 8 on/off 
commands, 5 telemetry channels and a serial port for the solar cell 
experiment telemetry. It also supports the Digital Comms Relay support 
of the PCsat/APRS mission. The packet uplink is on 145.825 MHz and the 
default downlinks are in the 435 MHz band to avoid any possible 
interference with existing ARISS missions. PCSAT2 will have quad 
redundant transmit inhibits for EVA safety issues, thus, it is also easy 
to turn off to avoid any issues with other UHF ARISS experiments that 
may be activated in the future. Also, the mission lifetime of PCSAT2 is 
only 1 year, because it is a sample-return mission, thus terminating any 
long term conflicts in spectrum management.

BAND PLANNING: One of the key issues with any Amateur Radio experiments 
on ISS is the requirement to avoid any mutual interferece between 
systems. For this reason, ARISS will need to eventually move all uplinks 
and downlinks into separate bands. This is so that multiple uplinks and 
multiple downlinks can be going on simultaneously. As it is, with both 
uplinks and downlinks on 2m, that band cannot be shared without mutual 
interference. Thus PCSAT2 is having to be designed as mode J to avoid 
transmitting on 2m, even though mode B (downlinks on 2m) is far superior 
to reaching schools and low-tech stations and meeting our mission 
objectives. There is much UHF equipment being planned for ISS, but until 
it is operational and ARISS has a long range plan, we are stuck with 
mode J. Ultimately, we think all ISS downlinks should be on 2 meters and 
are working up a draft paper to that regard. In the mean time, here is a 
possible band plan idea.


The PCSAT2 mission is intended as an opportunity to augment existing 
ARISS communications experiments with an external autonomous 
communications payload. In this regard, it has three potential uses:
# A UI-Digipeater to help ease congestion on the currently shared ARISS 
PMS (Packet Mail system)
# A PSK-31 transponder for multi-user communications to improve 
accessibility for schools and ARISS outreach programs.
# An FM Voice repeater for full duplex crew communications to facilitate 
crew-to-school ARISS contacts.

USER RECOMMENDATIONS: As was the case for PCsat, and in accordance with 
the rules for operation in the Amateur Satellite Service, all duly 
licensed operators worldwide are welcome to use the PCSAT2 transponders 
in accordance with the published guidelines. To keep users fully 
informed of their expected uplink requirements, we will publish and 
maintain an active and current User Service Agreement for guidance to 
all users.

This kind of open publishing of the detailed user expectations pioneered 
by PCsat was entirely successful and we were very pleased that Amateur 
Satellite Operators worldwide in general adherred well to the 
recommendations for the benefit of all.


# Antenna details:... Plan, Corner Plate, the Drawing and New idea, 
EZNEC antenna model.
# Antenna Photos:.... Corner Hinge Assy, Corner PCB and tuning ckts, 
Closeup details.
# Antenna Phasing:. UHF , VHF , Matching Ckt, PCB Layout, T/R sw, 
Assembly Notes.
# Assembly Plans:... Interface Brd, Phasing Board, Receivers, TXA, TXB, 
and TXC. Ibrd/TNCs.
# Command Ckts:.. List, Schematic, TXA/C ckts, TXB/RX/Heater ckts, TNC 
Resets, and XCD Hold Off.
# Communications:. Block Diagram . PSK31 10m RX photo1, Photo2, and Photo3.
# EVA Safety:....... TX Inhibit Plan , Block diagram .
# Failsafe timers:.... 96 hour timers.
# Fuse Selection:.... Use of PTC fuses in Vacuum rated at 50%. 100 ma 
Fuse 1.1 amp Fuse
# Frequencies:........ PCSAT2 Operations in the ITU Amateur Satellite 
Service and the IARU Rules.
# Ground Equipt:... GSE connector, User Equipment, EMI Test config, and 
GSE Test Setup.
# Interface Board Audio Ckt, Assy plan.
# Mechanical Items: Shelf Detail, PEC box, Handrail clamp, and a 
Connector Location sketch.
# Material Items:.... Parts List.
# Operations Plan:... Telemetry Collection Plan,
# PSK-31 Items:.... Miroslav Kasal's 29 MHz PSK-31 Receiever schematic .
# Power System:.... Distribution Ckt, Comms Power Budget, and the Actual 
Power Budget.
# Prototype Photos:..... Prototype TX and TNC pan.
# Requirements:...... Initial concept requirements for the AX.25 system.
# RF Subsystem:.... RF Functional Block Diagram and Frequency 
compatibility with ARISS.
# Telemetry Items:... Multiplexer, Telemetry Eqns, and the First TLM data.
# TNC Modifications:... KPC-9612 Mods
# Thermal Items:..... An early Thermal Approximation
# Unresolved ideas:..Possible LED Status Indicators (not implemented).
# Wiring Items:......... Cables , Harness , Original Coax , Final Coax , 
RX internal and TX internal .

PCSAT2 TELEMETRY SCREEN: The screen below shows what the PCSAT telemetry 
screen looks like. Whenever PCSAT2 is on the air, even on the ground in 
testing, you can monitor the APRS worldwide Internet system and see it.

PROTOTYPE Circuit Boards:

Click for high-res

The TNC COMM system (one of 2) and the dual receivers and dual transmitters.

The digital communications relay will operate within the ITU regulations 
for educational/outreach operations in the Amateur Satellite Service, to 
provide simple Satellite digital communications for amateur satellite 
operators and educators and possible remote environmental sensors 
worldwide Examples . This comms mission will provide a follow-on 
extension to the educational communications mission of PCsat, Boats at 
sea, cross country travelers, expeditions, or other travelers far from 
existing APRS terrestrial communications infrastructure. The Transponder 
and PEC data is captured by existing PCsat-to-Internet ground stations 
and fed into the existing worldwide internet linked APRS system. The PEC 
mission would join ISS, MIR, PCsat and several other on-orbit 
experiments (ASTARS) that have been conducted over the years leading up 
to this exciting capability.

Here are several additional PHOTOS, DRAWINGS and Documents:

# Terminal Node Controller (photo)
# TNC mods for telemetry
# UHF 2 Watt Transmitter (photo) (VHF shown, but UHF is similar)
# VHF receiver (photo)
# Evolution/Chronology of this project.

The AX.25 segment of the PCSAT2 communications mission has been 
demonstrated a number of times in space via PCsat, MIR School tests, the 
Shuttle SAREX, and the SPRE mission. . It is also a spin off of a 
previous launch opportunity that we had in 1998 called NATSweb that 
almost got launched on SEA-LAUNCH.. The PCSAT2 Communications mission is 
a project to produce a viable external ISS payload in a very short time 
frame using off the shelf components where possible. Here are the 
background topics of design:

# PHOTO of original RF model with MLI blanket.
# Alternate Antenna idea.
# Connector assignments,
# Board layout
# 8 hour timer inhibit design.

APRS is the Automatic Position Reporting System that the Naval Academy 
uses for tracking its boats and a variety of other vehicles and networks 
using the APRS Automatic Position Reporting System . The PEC 
Communications transponder would be operated under the rules of the 
Amateur Satellite Service and the rules of the FCC.

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Midshipmen Amateur Radio Club
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