The Midshipman Space Technology Applications Research (MidSTAR) Program
MidSTAR is a general-purpose satellite bus capable of supporting a variety of space missions by easily accommodating a wide range of space experiments and instruments. The integration of the experiments with the satellite bus must be accomplished with minimal changes to the satellite bus design. MidSTAR is intended to be a relatively low-cost, quick response platform accommodating small payloads approved by the Department of Defense (DoD) Space Experiments Review Board (SERB) and awaiting launch through the DoD Space Test Program (STP).
MidSTAR satellites will be one of two types. MidSTAR is designed for use on the Expendable Secondary Payload Adaptor (ESPA) Ring developed by Air Force Research Laboratory (AFRL) for placement on Delta IV or Atlas V expendable launch vehicles. MidSTAR is a Class D spacecraft, produced at minimum cost with a correspondingly higher technical risk in production and operation. It is intentionally simple in design and rugged in construction, using commercial off-the-shelf “plug-and-play” components to the greatest extent possible. Component development and circuit-board level design are accomplished only when necessary.
MidSTAR is a project of the United States Naval Academy (USNA) Small Satellite Program (SSP) under the sponsorship of STP. USNA SSP gratefully acknowledges the technical assistance of the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center, Computer Sciences Corp, CNS Systems Inc., the US Naval Research Laboratory (NRL) and Honeywell in the construction of MidSTAR-1. Financial assistance to the USNA SSP was provided by The Boeing Co. through a grant to the USNA Alumni Association and Foundation.
The baseline MidSTAR mission includes a single spacecraft under the command and control of a single satellite ground (SGS) station located at USNA, Annapolis MD. (Lat. 38.98 N, 76.49 W). The ground station forwards downlinked data files to the Principal Investigators via the Internet. Secondary ground control will be available on an as-needed/space-available basis through Naval Postgraduate School (NPS), Monterey CA (36.6 N, 121.89 W). Launch segment for the MidSTAR class of payloads is either the Delta IV or Atlas V EELV. The orbit will be tailored to payload requirements; where no requirements exist, the orbit of the primary payload or one of the other secondary payloads will be accepted. In order for the spacecraft to be seen from USNA SGS at an elevation greater than 30 degrees and range simultaneously less than 900 km, the orbit must be 500 +/- 200 km with inclination greater than 35 degrees.
MidSTAR-1 Mission (USNA-5)
MidSTAR-1 is the first implementation of the design. It was commissioned by STP to carry the Internet Communications Satellite (ICSat) Experiment for SSP (no. 39 on the 2002 SERB List) and the Configurable Fault Tolerant Processor (CFTP) Experiment for NPS (no. 34 on the 2002 SERB List).
Support ICSat and CFTP for two years; support additional USNA and NASA experiments on a space-available basis.
One hundred percent success will be the successful launch and operation of the satellite with full support for all experiments for two years.
Fifty percent success will be the successful launch and operation of the satellite with
- full support of one primary experiment for two years;
- full support of any two experiments for one year; or,
- partial support of all experiments for two years.
Thirty-three percent success will be the successful launch of the satellite and full operation of the satellite bus with partial support of any combination of primary and secondary payloads for any length of time.
Mission Log9 March 2007: MidSTAR-1 flew as part of the STP-1 mission on a United Launch Alliance Atlas V from Cape Canaveral Air Force Station. Liftoff occurred at 0310 UTC; spacecraft separation occurred at 0332 UTC. USNA SGS successfully acquired communications with the spacecraft during the first pass over Annapolis MD at 0459 UTC. The spacecraft was operating nominally in SAFE mode.
14 March 2007: Discovered that the line-of-sight (LOS) for maximum sun noise was approximately1.8 deg of azimuth off of solar optical LOS, indicating that the antenna was improperly collimated. Realigned feed to eliminate the collimation error. Installed latest version of NOVA software at 1930 UTC.
21 March 2007: CFTP turned on at 2217 UTC to add 6W continuous to the EPS load and lessen charging stress on the batteries.
28 March 2007: MiDN turned on at approximately 2400 UTC. Spacecraft stopped responding to all ground commands subsequent to this pass.
4 April 2007: Replaced a 1 MHz IF filter in the ground receiver with a 300 kHz filter, effectively adding 3dB of gain to the downlink. First use of "firecode reset" of spacecraft at approximately 2130 UTC. This command toggles the reset switch on the MIP-405 processor and reboots the operating system. This reset returned the CFTP and MiDN experiments to "off" and cleared all command buffers. At 2324 UTC the spacecraft responded to a "transmitter on" command. Telemetry confirmed that the reboot was successful.
6 April 2007: Implemented correction for doppler to ground receiver tuning.
Selective download of MiDN files retrieved 71 files of 92 bytes each which
were delivered to the Principal Investigator (PI). This is the first successful
retrieve of science data from the spacecraft. With this milestone, MidSTAR-1 has
satisfied the criteria of 33% mission success.
26 May 2007: NCSU turned on at approximately 1900 Z.
29 May 2007: First data package delivered to NCSU PI. All four experiments are on and delivering data to the PIs.
15 June 2007: Removed two bias-tees from the downlink path, effectively adding 1.5 dB of gain to the downlink. Added manual trim to azimuth tracking.18 June 2007: NASA press release announces success of NCSU.
20 June 2007: Added manual trim to elevation tracking.
5 September 2007: Spacecraft computer froze as a result of unknown influences, most likely radiation-induced upsets. This happened while the spacecraft was in full sun and with the power drains (30 W) on to prevent battery overcharging. Without the computer to cycle the drains off, the spacecraft remained in a continuous negative net power configuration which eventually drained the batteries. When the battery voltage dropped below 8 V, the electronic switches for the drains defaulted to off, returning the spacecraft to positive net power and allowing the batteries to recharge.
7 September 2007: Once the batteries had recharged sufficiently, the computer restarted successfully. Restart occurred 48 hours after the initial event. No telemetry from the spacecraft or any experiment is available for that 48 hour period. Telemetry indicates that normal operation has resumed, but all experiments are off pending post-event analysis and the development of a plan to bring them back online.
12 September 2007: CFTP restarted.
21 September 2007: MiDN restarted.
|Orbital Elements||Spacecraft Status|
|Epoch||08091.64460375||Battery Voltage||33 V|
|Inclination||46.0324||Battery Temperature||29 C|
|Right Ascension of the Ascending Node||195.1651||Solar Panel Temperature||29 C|
|Argument of Perigee||324.1894||NCSU||On|
MidSTAR-2 Mission (USNA-8)
MidSTAR-2 is currently undergoing initial concept development. It will be a second implementation of the mod 1 design, incorporating lessons learned from the experience with MidSTAR-1. Consideration of candidate missions and payloads is currently underway. Click on the links for further information.