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fahnen/4.jpg Eagle Fall 2004 Report
Launch Pad Return

AMSAT Eagle Project

Fall 2004 Status Report

By Richard M. Hambly W2GPS

The Eagle satellite is the focus of AMSAT's new Vision Statement. The satellite has been in the design phase since Dick Jansson WD4FAB presented his seminal paper at the 2000 AMSAT Symposium and has been refined at meetings in Denver CO in July 2001 and Orlando FL in October 2002. Another design meeting was held this past Summer. This presentation will provide the current status of the Eagle design activities.

Figure 1: Eagle with Solar Panels Deployed


The AMSAT Eagle project has been under consideration since it was originally proposed by Dick Jansson WD4FAB at AMSAT's 18th Space Symposium in Portland Maine on October 28, 2000. Dick's paper "So You Want to Build a Satellite" is published in the 2000 Proceedings

The first Eagle project design meeting was conducted July 14, 2001 at the Hilton Garden Inn in Denver, Colorado1. At this meeting two designs were considered and Dick's approach was selected. It was also decided to minimize propulsion by searching for a geosynchronous transfer orbit (GTO) launch and use propulsion only to stabilize the orbit by raising perigee, if necessary.

The second Eagle project team meeting was conducted September 28, 2002 at the Travelodge hotel in Orlando, Florida2. At this meeting the space frame, module packaging and thermal designs ware reviewed and an overall architecture considered that would accommodate a variety of popular operational modes as well as support for some of the microwave bands. Lou McFadin W5DID presented a design proposal for Sun and Earth sensors and was given the goahead to purchase parts and to pursue these designs in coordination with a team at Santa Rosa Jr. College in California.

A Renewed Emphasis on Eagle

The AMSAT Board commissioned a new Strategic Planning committee consisting of board members, officers and advisors that met February 20-22, 2004 at the Airport Clarion Hotel in Orlando, Florida3. After an intense two days of work this committee produced new mission and vision statements for AMSAT that will guide the continuing efforts to develop a full Strategic Plan. This committee has met by teleconference every other week since the February kick-off effort to continue their work. The key result for the Eagle project is contained within the vision statement.

Our Vision is to deploy high earth orbit satellite systems that offer daily coverage by 2009 and continuous coverage by 2012...

This requires two HEO satellites by 2009 and three by 2012.

The Latest Design Meeting

The third Eagle project design team meeting was conducted July 16-18, 2004 at the Airport Clarion in Orlando, Florida4.This meeting was publicly announced through the AMSAT News Service (ANS) and all interested parties were afforded the opportunity to attend.

The primary goal of this meeting was to establish the requirements for the Eagle mission. The previous Eagle team meetings had left many unanswered questions that this group was determined to resolve. The team succeeded in achieving this goal, as will be seen in following paragraphs.

Two other important goals were achieved at this meeting:

  • every aspect of Eagle's development was assigned to a working group and
  • each working group was assigned an interim group leader.

Figure 2: Robin Haighton VE3FRH making a point while Jim Sanford WB4GCS
listens at the July 2004 Eagle Team Meeting

Eagle Requirements

The Eagle satellite is being built to support the AMSAT vision statement and will be designed to carry a set of payloads that will support the primary needs of the worldwide AMSAT community while providing both the builders and the users challenging, exciting, and valuable new features and technologies. The payloads will be carried by a modified version of the structure designed by Dick Jansson WD4FAB.

The requirements are summarized in the following outline.
1.0 Payloads

1.1 Transmitters
  1.1.1 V band 20KHz bandwidth using SDR techniques
  1.1.2 Two S Band 100KHz bandwidth Either transmitter can be driven by SDR or analog inputs
  1.1.3 C band wideband digital which includes telemetry
  1.1.4 All bands should be capable of being operated simultaneously

1.2 Receivers
  1.2.1 U band 100KHz bandwidth
  1.2.2 L band 100KHz bandwidth
  1.2.3 C band wideband digital

Figure 3: Payload Module Housings. The large Module will not be used in the latest design.

1.3 GPS (NASA)

1.4 CEDEX (Surrey Satellite Technology)

1.5 Cameras
  1.5.1 Narrow FOV on +Z axis
  1.5.2 Wide FOV on –Z axis
  1.5.3 Cameras should survive all beta angles.

1.6 Telemetry beacons active on all transmitters
  1.6.1 The IHU will provide digital data and clock to the transmitter. The transmitter itself is responsible for data delivery.

1.7 Command uplinks on the U and L receivers
  1.7.1 Demodulation to baseband audio is in the receiver

2.0 Structure and Physical Properties

2.1 Mass
  2.1.1 100Kg or less

2.2 Size
  2.2.1 600mm by 600mm by 450 mm with fixed and deployable solar panels.

2.3 Stabilization
  2.3.1 Spin stabilized ( + Z Nadir pointing at apogee) 1-15RPM

2.4 Orbit
  2.4.1 High apogee elliptical

2.5 Attitude Control
  2.5.1 Magnetorquers and nutation dampers
  2.5.2 Sensors The Sun sensors will measure the sun at all angles and attitudes The Earth sensor will measure the attitude of the spacecraft with respect to the Earth while its distance is within two radii of the Earth's surface.
  2.5.3 The satellite will stabilize to the desired attitude in 72 hours.

2.6 Propulsion
  2.6.1 The simplest system that will accomplish a desirable orbit and is acceptable to the launch agency. Initial estimate is 60 meters per second delta velocity.
  2.6.2 The propulsion system should be modular

Figure 4: Lou McFadin W5DID, Dick Jansson WD4FAB, and Alan Bloom N1AL at the July 2004 Eagle Team Meeting

2.7 Structure
  2.7.1 Aluminum honeycomb panels forming core structure supporting internal modules and integrated with separation interface.
  2.7.2 Separation interface is located on the on –Z side, and is launcher dependent.
  2.7.3 Consider the possibility of side mounting

2.8 Magnetic Environment
  2.8.1 Magnetically clean as practically achievable

3.0 Thermal Control

3.1 Battery temperature should not exceed a -15 to +15C range.

3.2 Electronics module environment should be from -25 to +40C

4.0 Power Generation

4.1 Two fixed and four deployable solar panels with omni coverage.

4.2 Fault tolerant BCR and battery system that fails in an operational mode.

4.3 Buss voltage is 10 to 14 volts nominal.

5.0 Housekeeping

5.1 IHU-3

5.2 CAN-Do! Information buss

6.0 Antennas

6.1 High Gain +Z
  6.1.1 U (435MHz), L (1.2GHz), S (2.4GHz) and C (5.6GHz)

6.2 Omni Antennas, -Z (functional in all attitudes)
  6.2.1 V (145MHz), U, L and S

6.3 Omni Antennas +Z
  6.3.1 U, L and S

C-C Rider Payload

An exciting new payload will be carried by Eagle based on a design concept first put forward by Tom Clark W3IWI that he calls CC Rider. This has evolved based on the "Dream Payload" presentation made at the July 2004 Eagle team meeting by Rick Hambly W2GPS to include elements of four previously separate proposals, now integrated into the new C-C Rider payload. They are:

  • KarnSat (~1Mbps),
  • C-C Rider (5GHz Band),
  • Software Defined Radio, and
  • IP in Space

Figure 5: Rick Hambly W2GPS and Phil Karn KA9Q studying C-C Rider Plans during July 2004 Eagle Team Meeting

This will be a totally new technology to the Amateur Satellite Service that is directed at putting access to high orbit satellites into the hands of the average Ham even for those living in apartments and restricted communities. While the basis of this technology is a digital carrier with error correcting codes, the applications are the same as the average Ham expects, voice, data, video, and other modes in both one-on-one and round table group conversation modes. There will be much more said about this in other presentations.

"Linear" Transponders

Eagle will have linear band-translating transponders that function much as those on previous high orbit satellites but are implemented in a unique new way. In particular the uplinks will be on U and L bands with downlinks on V- and S-band. This will support the popular "Mode B" and the modes made popular by AO-40, Modes U/S and L/S, as well as other combinations. Both uplink receivers and the S-band transmitters will support 100KHz bandwidths. The V-band transmitter will be limited to 20KHz, which will be the lower 20KHz of each of the receivers' bandwidths. It is not clear if both receivers and/or both transmitters will be able to be operated simultaneously, but that is not a requirement.

The implementation of these receivers and transmitters will use techniques developed by the world of amateur Software Defined Radios (SDR). This means digitizing the received 100KHz spectrum segments all at once at a high IF frequency and creating the 100KHz and 20KHz transmit spectrums similarly at a high IF frequency. The traditional IF matrix found in analog designs will be replaced with a digital matrix. There will be much more to say on this subject as the design develops.

Figure 6: Eagle with Solar Panels Removed.

To provide a safe backup system in case of a failure in the digital implementation of the linear transponders there will be two S-Band transmitters and either of them will be capable of being driven by the SDR driver or by a traditional analog linear driver. One or more of the receivers will also be capable of analog operation.


At the conclusion of the Eagle team meeting assignments were made so that all subsystems groups and management assignments now have individual points of contact so everyone will know who to contact on any issue. Some of these assignments are of an interim nature and those people will be actively looking for their replacements while other assignments will be more long lasting. The assignments as made during the meeting are as follows.

  • Project Manager: Jim Sanford WB4GCS
  • Chief Technical Officer: Rick Hambly W2GPS (acting)
  • Secretary: Stephen Diggs W4EPI
  • Structure and Thermal: Dick Jansson WD4FAB
  • Launch: Lee McLamb KU4OS (lead), Tom Clark W3IWI (Russian launches)
  • Guidance and Control - Ken Ernandes N2WWD
  • Sensors: Alan Bloom N1AL
  • Power Generation and Distribution: Lou McFadin W5DID
  • Propulsion: Stan Wood WA4NFY (lead), Daniel Schultz N8FGV, Ken Ernandes N2WWD
  • Housekeeping: Bdale Garbee KB0G (data interface), Chuck Green N0ADI, Lyle Johnson KK7P (IHU-3)
  • Antennas: Stan Wood WA4NFY
  • Payloads: Bob McGwier N4HY, Daniel Schultz N8FGV, Tom Clark W3IWI
  • GPS: Lou McFadin W5DID
  • CEDEX: Robin Haighton VE3FRH
  • Cameras: Gunther Meisse W8GSM
  • Command and Control/Telemetry: Stephen Diggs W4EPI, Stacy Mills W4SM

Design Approach

Each of the three Eagle team meetings discussed the viability of using open design techniques. It has been decided to attempt to design Eagle in the open. To the extent possible, all drawings, schematics, software source code and other design materials will be made available to the AMSAT membership, probably by placing the materials on the Web site. Membership input and feedback will be encouraged through forms provided on the Web site.

Figure 7: Eagle with Solar Panels in Launch Configuration

There are certain considerations that could limit or prevent the implementation of such an open design environment. They are as follows.

  • The security of the satellite, especially issues of certain command and control codes.
  • The use of commercial or other proprietary designs and products.
  • The desire of a designer to maintain his or her designs as private intellectual property as has been the tradition at AMSAT.
  • The International Traffic in Arms Regulations (ITAR), U.S. Government Subchapter M, Title 22, Code of Federal Regulations, Parts 120 through 130 (22 CFR 120-130).

Figure 8: Stan Wood WA4NFY explaining orbital dynamics at the July 2004 Eagle Team Meeting

It remains to be seen to what extent we can make Eagle an open project but the team will be encouraged to pursue open design techniques wherever practical.

Figure 9: Gunther Meisse W8GSM coming up with another idea at the July 2004 Eagle Team Meeting


So You Want to Build a Satellite, Dick Jansson WD4FAB, Proceedings of the AMSAT-NA 16th Space Symposium, October 27-29, 2000.

  1. Present at the July 2001 Eagle design meeting were Russ Tillman K5NRK, Chuck Green N0ADI, Stan Wood WA4NFY, Lou McFadin W5DID, Jim White WD0E, Lyle Johnson KK7P, Paul Williamson KB5MU, Bdale Garbee KB0G, Phil Karn KA9Q, John Connor NJ0C, Art Feller W4ART, Mike Kingery KE4AZN, Rick Hambly W2GPS, Ed Collins N8NUY, Mark Kanawati N4TPY, Robin Haighton VE3FRH, Dick Jansson WD4FAB, Tom Svitek, Dan Schultz N8FGV, and Brian Straup N5YC.
  2. Present at the September 2002 Eagle design meeting were Shea Ferrin, Bdale Garbee KB0G, Chuck Green N0ADI, Robin Haighton VE3FRH, Rick Hambly W2GPS, John Isella WA1ZVZ, Dick Jansson WB4FAB, Lyle Johnson KK7P, Lou McFadin W5DID, Russ Tillman K5NRK, Jim White WD0E, Stan Wood WA4NFY, and George (?).
  3. Present at the February 2004 Strategic Planning meeting were Robin Haighton VE3FRH, Rick Hambly W2GPS, Tom Clark W3IWI, Barry Baines WD4ASW, Lou McFadin W5DID, Stan Wood, WA4NFY, Martha Saragovitz, Art Feller W4ART, Jim Jarvis N2EA, Bill Birden WB1BRE, Gerald Youngblood AC5OG, Dick Jansson WD4FAB, Lee McLamb KU4OS and Stephen Diggs W4EPI. Gunther Meisse W8GSM was unable to attend due to sudden illness.
  4. Present at the July 2004 Eagle design meeting were Ken Ernandes N2WWD, Bdale Garbee KB0G, Chuck Green N0ADI, Robin Haighton VE3FRH, Rick Hambly W2GPS, Dick Jansson WD4FAB, Lyle Johnson KK7P, Phil Karn KA9Q, Lou McFadin W5DID, Tom Clark W3IWI, Bob McGwier N4HY, Lee McLamb KU4OS, Karl Sandstrom K5MAN, Jim Sanford WB4GCS, Daniel Schultz N8FGV, Stan Wood WA4NFY, Alan Bloom N1AL, Lynnette Evans W3GZZ, Paul Tabatschkow N3UD, John Conner NJ0C, Stephen Diggs W4EPI and Gunther Meisse W8GSM.

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