News

April 30, 2002: Information on MICS failure

The following is from an email by Joe Fennell of the Aerospace Corporation detailing the MICS instrument failure on April 30, 2002.

"I looked into the MICS +5V monitor and put together a plot of its history following the failure. (see attachment) Since the value plotted is an analog output to the spacecraft, it did not require that the DPU be running to report values. I do not remember the exact cadence of the measurement. I tracked value changes during the interval 11:16 through 11:44 UT on 30 April. The plot shows that the +5V line dropped to 4.5-4.525 v for at least three sample intervals the recovered slowly to 4.625. At that point the MDPU started putting out TM again. The voltage stayed in the 4.625-4.650 range until ~11:41 when it recovered to 5.000-5.025 V."

"In the science TM we do a readout of a science data record every five minor frames (mf 0, 5, 10 etc.). Thus we can time the failure to within 5 mf in a major frame. The last TM out was mf = 5 relative to the major frame closest to 11:16:48. From that point on, there was no TM out (MDPU not servicing the TM) until the MDPU recovered at about 11:20:29 at mf=0. At that point the science TM in the MICS EVENT-DATA stream (shared with the HSKP data) had all values high and the detailed science data stream (a separate serial interface stream with its own clock) was all zeros, as noted previously."

"In our housekeeping display the BUPS current did not change at all. It read a constant 97.02 ma throughout the interval above. It is a measure of the +28 volt current only, according to the MICS documentation. Pre launch, the BUPS current was 96-103 ma, depending on the CHPS HV level, CHPS Mode and temperature. At our normal mode with CHPS Step=4 the current was generally 96-97 ma. Thus the BUPS current is consistent with no change, even during the long period that the MDPU was running with the +5V line low. This indicates the load was not inside the BUPS itself. That means it must be in the MICS circuitry external to the BUPS (such as the I/F circuits or light diode receivers) or in the MDPU. Those MICS external circuits use the +5 and -6.8 V power from the MDPU."

November 28, 2000

A new section for the Polar spacecraft is now up and running. The data plots for this satellite are hosted on the CCR website.

Another new section covering the Cluster II spacecraft should be finished by late this week.

The following changes have been made to the site:

• Added a section to cover the Polar spacecraft. Includes a description of the satellite and a link to data being served at the CCR website.

Things being worked on:

• A new section covering the Cluster II spacecraft.
• A new CGI system for the ATS-6 and SCATHA data sets. This system will allow for easier browsing of our available data.

November 8, 2000

Welcome to the new BUSPACE. If this page looks funny then you do not have a HTML 4.0/CSS 1.0 compliant browser.