JAWSAT (Joint Airforce Academy / Weber State University Satellite)
The JAWSAT minisatellite mission is a collaboration between the United States Air Force Academy (USAFA, Colorado Springs, CO) and the Center for Aerospace Technology (CAST) at Weber State University (WSU) in Ogden, Utah. The JAWSAT mission is also known under the designations of “P98-1” as well as OSP (Orbital Suborbital Program) by the USAF. The OSP label results from the inaugural flight of the new launch vehicle, the Minotaur rocket, derived from Minuteman-2 missile parts and Pegasus rocket stages, which placed JAWSAT into its orbit.
The JAWSAT project was initially designed (1994) with a pulsed-plasma thruster to train Air Force Academy cadets. In its new dedication (April 1998), JAWSAT is mainly functioning as a multi-payload adapter for the following four satellites: 1) 2) 3) 4)
• ASUSat-1 (Arizona Sate University Satellite-1)
• FalconSat of the USAF Academy, Colorado Springs
• OPAL (Orbiting Picosat Automatic Launcher) of SSDL (Space Systems Development Laboratory) at Stanford University with the following picosats (6 subsatellites):
- PICOSAT (2) of the USAF (DARPA funding), developed by The Aerospace Corporation
- Artemis of Santa Clara University (3). They were named: Thelma, Louise, and JAK
- StenSat (1)
• OCSE (Optical Calibration Sphere Experiment) of AFRL (Air Force Research Laboratory).
Table 1: Summary of JAWSAT mission payloads
Figure 1: Photo of the fully integrated JAWSAT MPA spacecraft (image credit: OSSS) 5)
A variation on the load bearing spacecraft approach was flown on the JAWSAT inaugural mission, in which the primary payload (JAWSAT) was a Multiple Payload Adapter (MPA) from which four small satellites were separated. The JAWSAT MPA technology, in a sense “a mass-transport” capability to space, was developed at CAST of Weber State University and built by OSSS (One Stop Satellite Solutions) and of Ogden, UT. The objective is the deployment of a number of small satellites. The design elements/features of MPA are:
• Complete three-axis attitude determination and control
• Lightweight isogrid space frame
• Flight computer with EDAC memory module
• Onboard multi-channel imaging system
• Onboard power system with battery charge regulation
MPA for JAWSAT consists of six waterjet-cut aluminum isogrid pieces assembled in a “windmill” design, a frame of 71 cm x 71 cm x 76 cm (the isogrid space frame is composed for four vertical panels, a top and a bottom panel that can be arranged in a number of configurations). MPA can be quickly and easily proportioned for multiple applications and payloads. JAWSAT is three-axis stabilized. Since attitude determination and control are fundamental to this mission, JAWSAT is equipped with several systems for attitude determination and a 3-axis stabilization system.
The overall S/C structure has dimensions of: 90 cm x 90 cm x 107 cm, its mass is 191.4 kg, 80 W of average power are provided from solar panels.
The ACP (Attitude Control Platform) of CAST uses tiny reaction wheel canisters (4), and a magnetometer; ACP is used to orient JAWSAT during the deployment of its payloads. ACP may also be used for a free-flying satellite with all the attributes needed to operate a mission. On this testbed spacecraft, a number of attitude sensors are available for comparison and possible integration. The ACP components include: 6)
• BANTAM series reaction wheels
• Magnetic torquing coils
• Coarse and fine sun angle sensors
• Horizon angle sensors
Figure 2: Illustration of the ACP (image credit: CAST)
RF communications: Downlink transmission in UHF, frequency 437.175 MHz (FM/ FSK/GMSK, 38.4 kbit/s), also frequency of 437.070 MHz (FM/ FSK, 9.6 kbit/s). In addition, S-band at 2403.200 MHz (FM/ FSK/GMSK, 38.4 kbit/s).
Launch: JAWSAT was launched on Jan. 27, 2000 (UTC) with an OSC (Orbital Sciences Corporation) Minotaur vehicle (maiden flight of a converted surplus Minuteman-2 motor combined with the upper stages of the Pegasus-XL booster) from the commercial California Spaceport at Vandenberg, operated by SSI (Spaceport Systems International). Other companies involved in the launch were: OSSS (One Stop Satellite Solutions) and TRW. The OSP program is managed by the Air Force's Space and Missile Systems Center (SME/TE) at Los Angeles Air Force Base, CA. 7)
All satellites were deployed successfully from the JAWSAT mothership. 8)
However, it turned out that:
• ASUSat-1 telemetry was received only sporadically at various stations around the world, in particular by amateur radio ground stations. The first contact confirmed that the S/C had been successfully deployed and was functioning in orbit. During initial passes, the ASUSat students successfully commanded and controlled the satellite. Initial systems checkout confirmed that the communications, commands, power regulation, data acquisition, and structures/deployment subsystems were performing as expected. The last report received from ASUSat-1 was by the SUNSAT team (Stellenbosch University, South Africa) at fourteen hours into the mission. This reception included a telemetry frame that confirmed that the satellite did indeed have a critical problem in the power system. Unfortunately, this problem prevented the solar arrays from supplying power. Predicted lifetime of the satellite on battery power alone was estimated to be fifteen hours.
• The FalconSat-1 spacecraft failed on-orbit soon after deployment, apparently due to a power failure. No useful science data was returned, despite repeated recovery attempts. The mission was declared a loss after about a month in orbit.
Note: OPAL with its six subsatellites as well as FalconSat-1 are described under separate headings on the eoPortal.
Orbit: Sun-synchronous near-circular orbit, 753 km x 805 km, inclination = 100.2º, period = 100.36 min.
Figure 3: JAWSAT mission logo (image credit: SSDL)
Figure 4: Backside of the JAWSAT MPA spacecraft (image credit: OSSS)
JAWSAT payload complement:
After deployment of the four satellites (ASUSat-1, FalconSat-1, OPAL and OCSE) JAWSAT continued its orbit. JAWSAT included another payload which remained attached to the S/C structure, namely PEST.
PEST (Plasma Experiment Satellite Test)
PEST is an experiment provided by NASA/MSFC. PEST remains attached to JAWSAT. The objective of PEST is to study plasma (electrically charged gases), at orbital altitudes. PEST uses instruments and the DPA (Deflection Plate Analyzer) which flew on previous Shuttle missions. DPA uses a new analysis technique that can measure multiple ion streams and determine the intensity, flow direction, and energy and mass distributions for each stream. The space test requires comparing the DPA with instruments that have been successfully used in space many times.
Figure 5: Illustration of PEST (image credit: CAST)
SRSS (SoftRide for Small Satellites)
A full-spacecraft isolation system was implemented between the avionics deck interface and the payload adapter cone. This was not an option under the launch vehicle contract. Instead, it was an isolation system developed and produced by CSA Engineering under contract to AFRL (Air Force Research Laboratory) and provided to Orbital. 9)
Figure 6: Photo of the integrated SRSS with the payload adapter cone (image credit: OSC, AFRL)
OCSE (Optical Calibration Sphere Experiment) of AFRL
OCS is a 3.6 m diameter kapton/aluminum balloon that is designed to orbit the Earth for up to two years (total mass of 22 kg, mass of balloon only = 1.7 kg). The highly-reflective silver-colored balloon was built by L'Garde, Inc. of Tustin, CA. The overall objective is to further refine the ability to track high-flying satellites. The Air Force uses its optical telescopes and SLR (Satellite Laser Ranging) network of ground stations to periodically track OSCE.
The balloon was deployed from a canister of 0.48 m in length and 0.41 m in diameter (Figure 7) shortly after orbit injection and inflated (the sphere became rigidized after inflation and the canister remained attached to the inflated sphere as specified). OCS was assigned the catalogue number of 26062 (Cospar 00004B). 10)
Orbit of OCS: Near-circular sun-synchronous (terminator) orbit, altitude = 750-770 km, inclination = 100.2º, period = 100.4 minutes. OCS had a standard visible magnitude of +5 and required a dark sky for it to be observed.
Status of OCSE mission: After successfully completing its one year mission, the OCSE reentered the Earth's atmosphere on March 5, 2001.
Figure 7: OCSE (black hexagon) mounted on JAWSAT payload and integrated to the experimental Minotaur rocket (image credit: L'Garde)
Figure 8: Test deployment of OCSE (image credit: L'Garde)
Figure 9: Alternate view of the deployed OCSE (image credit: L'Garde)
1) Jay L. Smith, D. Richards, M. Wood, G. Sharp, W. Clapp., “The JAWSAT Mission: Final Report and Lessons Learned,” Proceedings of the 14th AIAA/USU Conference on Small Satellites, Logan, UT, Aug. 21-24, 2000, SSC00-V-4
2) Overview of JAWSAT Payload,” Jan. 14, 2000, URL: http://spaceflightnow.com/osp/jawsat/000114jawsatoverview.html
3) “OSSS and Weber State University Satellite Due to Launch on Experimental Military Launch Vehicle,” URL: http://polimage.polito.it/picpot/documentazione/lanciatori/OSSS.pdf
4) E. Anderson, J. Smith, “New technology for increased delivery potential and access into space,” Proceedings of the IEEE Aerospace Conference, Big Sky, Mt, USA, Vol. 1, pp. 355-362, March 7-10, 2001
6) J. L. Smith, “Attitude determination and control suitable for micro-spacecraft,” Proceedings of the IEEE Aerospace Conference, Big Sky, Mt, USA, Vol. 7, pp. 143-165, March 18-25, 2000
7) “Recycled Minuteman Roars into Space,” Space Today, URL: http://www.spacetoday.org/Rockets/Plowshares/Minuteman.html
8) S. Schoneman, S. J. Buckley, G. Stoller, L. M. Marina, C. B. Morris, “Demonstration of a New Smallsat Launch Vehicle: The Orbital/Suborbital Program (OSP) Space Launch Vehicle Inaugural Mission Results,” Proceedings of the AIAA/USU Conference on Small Satellites, Logan, UT, Aug. 21-24, 2000, SSC00-I-1
9) “Minotaur User's Guide,” OSC, March 2002, Chap. 8.1.3, 'Payload Isolation System', URL: http://snebulos.mit.edu/projects/reference/launch_vehicles/OSC/Minotaur_User_Guide.pdf
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates.