===================================================================== CONT11 Session Notes September, 2011 First session start: September 15, 2011 0:00:00 UT End of last session: September 29, 2011 23:59:59 UT The CONT11 sessions will be observed in UT days, i.e. in sessions of 0-24 UT. UT-day observing yields the most accurate combination and comparison of results from other techniques. It is also the likely operation mode of VLBI2010 observing. ===================================================================== Number of 24-hr sessions: 15 Participating stations: Badary, Fortaleza, HartRAO, Hobart, Kokee, Ny Alesund, Onsala, TIGO, Tsukuba, Westford, Wettzell, Yebes, Zelenchukskaya Average number of observations per day: 10,829 Total number of campaign observations: 162,434 ===================================================================== Schedules The sources for the schedules are based on the best 120 sources of the current geodetic source catalog. Three sources that showed more than 20% of non-detections in the R1 and R4 sessions of the first half of 2011 have been removed, resulting in 117 sources used for creating the schedules. SNR Targets: Minimum SNR for all baselines (except with TIGO): X-band (margin 5): 20 S-band (margin 3): 15 Minimum SNR for baselines with TIGO: X-band (margin 5): 15 S-band (margin 3): 12 ===================================================================== Special Instructions Refer to the schedule summary at the end of the file for the overall schedule of sessions. One or two (or three for Zc) session days will be recorded onto one disk module. Several session days are paired together for sharing disks creating the following recording groups for all stations except Zc. Recording groups for Bd, Ft, Hb, Hh, Kk, Ny, On, Tc, Ts, Wf, Wz, Ys: C1101 ==> ---+ C1102,C1103 ==> | C1104,C1105 ==> | C1106,C1107 ==> | C1108 ==> +---> Washington Correlator C1109,C1110 ==> | C1111,C1112 ==> | C1113,C1114 ==> | C1115 ==> ---+ Recording groups for Zc, include some three session groups: C1101 ==> ---+ C1102,C1103,C1104 ==> | C1105 ==> | C1106,C1107,C1108 ==> +---> Washington Correlator C1109,C1110,C1111 ==> | C1112 ==> | C1113,C1114 ==> | C1115 ==> ---+ All CONT11 sessions will be correlated at the Washington Correlator. This includes also the R1-equivalents. CABLE CAL CHECK: A cable check should be performed before the start of the first session and after the end of the last session. Stations should NOT do any cable cal checks (or anything else that might interrupt the 5 MHz to the antenna unit) between sessions. SYSTEM CHECKS: With the exception of C1101 and C1115, all CONT11 sessions have a one-hour slot for each station to perform system and pointing checks. The one-hour slots for all stations are staggered over the 24-hour period of the session. Stations should check the system and pointing during the one-hour slot preferably during the first 30 min of the slot (to allow for corrective measures in the subsequent 30 min if necessary). The station is scheduled in tag-along mode during the one-hour slot allowing the station to leave and re-enter the session at any given moment of the slot. They should rejoin the schedule as soon as practical. The stations observing the various Intensive sessions have a 90-min break from the CONT11 schedule followed by a 30-min period for system and pointing checks, resulting in a two-hour slot (readily identifiable in the table below by the 1/4 and 3/4 of an hour start and stop times). The "Intensive stations" were also scheduled in tag-along mode during the two-hour slot. The system and pointing checks, however, should be performed after the Intensive observation. The slots are as follows (for C1102 through C1114): Weekdays: Bd 19:45 - 21:45 UT Ft 14 - 15 UT Hb 3 - 4 UT Hh 12 - 13 UT Kk 18:15 - 20:15 UT Ny 13 - 14 UT On 8 - 9 UT Tc 16 - 17 UT Ts 1 - 2 UT Wf 15 - 16 UT Wz 18:15 - 20:15 UT Ys 9 - 10 UT Zc 7 - 8 UT (all days except C1102 and C1109) 19:45 - 21:45 UT (for C1102 and C1109 only) Weekend: Bd 19:45 - 21:45 UT Ft 14 - 15 UT Hb 3 - 4 UT Hh 12 - 13 UT Kk 7:15 - 9:15 UT Ny 13 - 14 UT On 8 - 9 UT Tc 16 - 17 UT Ts 1 - 2 UT Wf 15 - 16 UT Wz 7:15 - 9:15 UT Ys 9 - 10 UT Zc 11 - 12 UT Stations should rejoin as soon as practical after their system and pointing checks. Before rejoining please consider the slewing time from the antenna's current position to the next scan, including which cable wrap the antenna should be on. You may need to pick a slightly later scan in order to have enough slewing time and reach the correct cable wrap. A suggested technique for breaking away from the schedule is to use the "halt" command to stop the schedule to begin the system checks. Once checks are complete and the scan to rejoin the schedule has been determined, a suggested way to rejoin is to use a command of the form schedule=session,#line where "session" is the name of the .snp schedule file and "line" is the line number for the scan shown in the schedule listing. MODULE SHIPPING: The modules can be sent as soon as no further recording is planned on them. This can be at the end of a single session (C1101, C1108, or C1115) or at the end of a set of sessions (recording group). Stations should label the modules to indicate which session(s) the modules contain. The R-type sessions will be processed within the nominal 15 day time delay for the rapid sessions. These sessions require that the modules be shipped to the correlator by express. The expedited shipment holds also for modules that contain both rapid and non-rapid data. Rapid sessions are C1101, C1105, C1108, C1112, and C1115. MIDOB: Each station should verify that their MIDOB procedure completes in 20 seconds or less. The minimum scan length is 20 seconds. MARK 5B OPERATIONS: Stations using Mark 5B recorders should be aware that they should not automaticallt re-sync the 5B if they receive the error message: ?ERROR sc -24 setcl: Mark 5B syncerr_gt_3, use fmset 's' option to fix. This error message is poorly worded. You should not use fmset to re-sync the Mark 5B unless fmout-gps is greater than +/- 30 milliseconds. If you do a re-sync, please be sure the time is correct as well. In other cases, you should not reset the Mark 5B time unless it is off by more than +/- 5 seconds (as shown by setcl in units of 0.01 seconds). For the station using a DBBC (Hb), if the fmout-gps starts to change continuously, it may be worthwhile to reset the DBBC (and re-sync and set the time in the 5B with fmset), if that will stop the continuous changing. B2A PROBLEM: Please be aware that for some Mark 5 recorders it is not possible to record a module in bank A if it has already been recorded on in bank B. There should not normally be a need to move a module from one bank to another. However, if it does, please be aware of this restriction. MARK 5 FIRMWARE ISSUE: Two stations (Ft and Wz) have Mark 5 firmware version that do not fully support use of SATA disks. We believe a method to deal with this is: With the Mark5A program not running, insert a SATA module in bank A and turn the latch. Then start the control program Mark5A. After that, it should be possible to use any combination of modules in the Mark 5A, except, you can never put a SATA in bank B. These two stations should test this method as soon as possible. If it works, they should be able to use SATA modules without problems, except a SATA module cannot be used in bank B. This means that for module changes when the next module to be recorded is SATA, it cannot be pre-mounted in bank B. When this happpens, it will prevent using automated schedule changes at the day changes. In this case, a spare PATA module can be put in bank B in case the module in bank A fills prematurely, but the next SATA module will have to installed at the schedule change (or after recording has moved to bank B module if the module in bank A fills prematurely). If the above method does not work or will cause operational problems, please inform Ed (Ed.Himwich@nasa.gov) and we will find another solution. LOG FILES: Log files should be ftp'd to an IVS Data Center every day, following the end of each session. This will ensure the logs are available for the correlator to set up for pre-passing and for processing the rapid sessions. It will also let the status of each station be checked. Automatic scripts process the logs each night, the summary files and plots are posted on the session web page, and the session performance matrix is updated. STARTING SCHEDULES: For the first schedule you will need to make sure that you start it early enough to reach the first source. Please check to make sure you go to the right cable wrap for this scan. If your antenna interface does not support the "cable wrap" parameter for the "source=..." you may need to force the antenna to the right wrap manually. Of course changing the wrap will require additional time if it is needed. The cable wrap needed can be found in the DRUDG listing (for example the one from option 5) or from the "source=..." command in the .snp file. Starting with the second schedule we have allowed enough time to slew to the new source from the last source in previous schedule if the schedule is started by 0000 UT. The cable wrap should be handled correctly without taking special action if this rule is followed. In order to get as much data, and with as few gaps, as possible, we have allowed a minimum of only three minutes for changes between schedules. In other words, at a schedule transition the old schedule will end recording by 23:57:00 UT and the operator needs to start the new schedule before 00:00:00 UT. This is a short time, but we think it should be sufficient. For stations with Mark 5 recorders we think that at most two operator actions should be needed for a schedule transition. The first action is that between some schedules it may be necessary to change the recording bank with a "mk5=bank_set=inc;" command and then wait up to 20 seconds for the recorder to settle for the "Selected" LED to come on. The second is that every schedule transition will require the new schedule to be started with a "schedule=..." command. The "bank_set" command should require less than 30 seconds for the operator to enter and 20 seconds or so for the Mark5 to complete since the module can already be inserted. The "schedule=..." command should require 30 seconds or less to enter. This still leaves an additional minute and a half or so in case an old module must be removed and a new one inserted and selected and/or there are minor problems. In case of a more serious problem, please rejoin the schedule as soon as possible. Since we are not expecting many problems, we didn't want to allow a lot of extra time to handle them, but we recognize that they may happen. Once the schedule has started, you will need to quickly enter a "mk5relink" to continue the schedule after the "halt" in "ready_disk". We aren't as familiar with K5 operations, but the personnel at Tsukuba have in the past felt that three minutes is sufficient time. Assuming that there is no need to insert a module, it is possible to automate the transition for Mark 5 stations. The cable wrap information is carried forward between consecutive schedules to make this possible. There are many possible ways to automate this. One is to place a procedure, perhaps called "change", in the "station" procedure library with contents similar to: "uncomment next two lines if a bank change is needed "mk5=bank_set=inc;" "!+30s schedule=c11nnxx,#1 where "nn" is the schedule number and "xx" is the station's two letter code. Before the schedule change time, the operator would enter a time schedule command such as: change@2011.ddd.23:58:00 where "ddd" is the day number. The contents of "change" would need to be modified for each transition, changing the schedule name and possible commenting/uncommenting the "mk5=..." and "!+30s" commands as appropriate. You will also need to comment out the "halt" in your "ready_disk" procedure. This approach has NOT been tested, but we expect it to work. If you want to use this approach, it can easily be tested before use and/or should be monitored the first time it is used. Other schemes are possible as well. READY, START, and STOP messages: Stations are requested to slightly modify their normal procedures for sending READY, START, and STOP messages. Please send the normal READY and START messages for the first experiment and the normal STOP message after the last experiment. Due to the quick transitions between schedules and the separate system check time, the procedure for the other messages should be modified to make them reasonable. A suggested scheme would be to send the STOP message as soon as convenient after the start of the next schedule. The START message for the new schedule can be sent as soon as convenient after that. The READY message can be sent after the system checks later during that schedule, summarizing the results for those checks and any other status information. If you normally use "msg" to send your READY, START, and STOP messages, you probably still can. However, for the second and following schedules the following changes are recommended: (1) For the STOP message, please be sure the correct (previous) session name is shown and enter disk inventory only for CONT11 modules. Any problems should be summarized in the "comments" text box. Please be sure to include information about any problems with disk modules requiring use of a spare. (As a reminder, please be sure to send a timely message about any disk module problem to ivscc@ivscc.gsfc.nasa.gov when the incident happens. The sooner the Coordinating Center is informed of a problem, the better the chance that a useful response will be possible.) (2) After sending the previous schedule's end message, select the START message form manually and enter the required information. Please verify that the name of the session is correct. If you have the name and time for the first source that was observed, please enter it. Otherwise, you can use 0000 as the time and "source" as the name of the source. (3) After performing the system checks, please select the READY message form manually and enter the information as appropriate including the session name. Please be sure to de-select the "auto-start" check-box on the form. You can turn it off persistently using the "auto-start" check box on the "Setup" menu. (If you do that, please be sure to re-enable it after CONT11 is finished.) If "auto-start" is accidentally selected when a READY message is sent, it may be possible to cancel the message on the START form before an erroneous message is sent, but if not, please don't worry about it. (As a reminder, *** please be sure to NOT do a cable check during the system checks. ***) MODULE TESTING: Please test all modules you will use for CONT11, including spares, before the session begins. To do this, please record a few seconds of data, do a "scan_check", and erase the data. There will not be time to test the modules during the session, but we expect failure will be rare. Please monitor the first "scan_check" after a change of module, particularly at schedule transition, to make sure the new module is working. If not, please change to a spare module and rejoin the schedule as soon as possible. Please set the bad module aside, inform the Coordinating Center (ivscc@ivscc.gsfc.nasa.gov) and only try to re-use it if you have otherwise run out of media toward the end of CONT11. ===================================================================== Table 1: CONT11 Observing Plan Summary Day Code Start End Correlator Rapid --- ----- ---------- ---------- ---------- ----- Wed system check cable check Thu C1101 258-000000 258-235700 Washington *R4* (system check) Fri C1102 259-000000 259-235700 Washington (system check) Sat C1103 260-000000 260-235700 Washington (system check) Sun C1104 261-000000 261-235700 Washington (system check) Mon C1105 262-000000 262-235700 Washington *R1* (system check) Tue C1106 263-000000 263-235700 Washington (system check) Wed C1107 264-000000 264-235700 Washington (system check) Thu C1108 265-000000 265-235700 Washington *R4* (system check) Fri C1109 266-000000 266-235700 Washington (system check) Sat C1110 267-000000 267-235700 Washington (system check) Sun C1111 268-000000 268-235700 Washington (system check) Mon C1112 269-000000 269-235700 Washington *R1* (system check) Tue C1113 270-000000 270-235700 Washington (system check) Wed C1114 271-000000 271-235700 Washington (system check) Thu C1115 272-000000 272-235959 Washington *R4* Fri cable check Notes for stations: - Do NOT do any cable checks other than the two checks shown. - Each schedule will end no later than the "End" time. - When schedule days change, enough time has been allowed to slew from the last source of the old schedule to the first source of the new schedule assuming the new schedule is started by 0000 UT. The actual first observation can be up to a few minutes after the nominal start. - Stations must send modules for the "Rapid" sessions express to the correlator, as usual. The correlator is Washington for all sessions. - Stations should label the disk modules to show which CONT11 session days are recorded. - Stations should confirm all initiated shipments to the correlators. - For the non-Intensive stations, there are one-hour slots for system checks (see Table in SYSYEM CHECKS). The system checks should preferably be performed in the first 30 min of the one-hour slot to allow for corrective measures in the subsequent 30 min if necessary. The re-entry can occur at any time during the one-hour slots, as the stations are added in tag-long mode during that period. - The observation of the Int1 and Int2 Intensives will continue during CONT11. There will be no Int3 Intensive. The slots for Intensive observing and system checks are two hours and aligned with the Int1 and Int2 Intensive observing periods. The stations Bd, Kk, Wz, and Zc will leave the CONT11 schedule at the beginning of their two-hour slots and re-join it after the Intensive and their system checks as soon as possible. The system checks should be performed in the last 30 min of the two-hour slot. The re-entry can occur at any time during the two-hour slots, as the stations are added in tag-long mode during that period. - If necessary, it should be possible to automate the change in schedules. If you want to do this and want advice, see above or please contact Ed (Ed.Himwich@nasa.gov). Notes for the correlator (WACO): - A disk module may contain data of one, two, or three (Zc only) observation days. The disk modules have labels according to the sessions being recorded. - The Int1 and Int2 Intensive sessions will be observed during CONT11. There are no Int3 Intensive sessions scheduled. The correlation of the Int1 and Int2 sessions has precedence over CONT11 correlation. - Five of the 15 CONT11 days are considered rapid turn-around sessions. These R1 and R4 equivalents are to be correlated first. The equivalents are: C1101 = R4, C1105 = R1, C1108 = R4, C1112 = R1, C1115 = R4. - The accumulation period (AP) should be set to 3 sec. ============================================================================== Table 2: Recording Groups and Module Usage Summary: ============================================================================= Bd Ft Hh Hb Kk Ny On Tc Ts Wf Wz Ys Zc Avg ============================================================================= C1101 1013 2037 1830 1671 2103 1791 2111 2824 1257 2240 1423 1612 1143 1774 ----------------------------------------------------------------- B G I D G D G G B G B D B ============================================================================= C1102 1028 1946 1764 1575 2114 1817 2146 2575 1265 2049 1486 1642 1163 1736 C1103 1049 1974 1846 1564 1998 1745 2105 2536 1294 2129 1505 1640 1158 1734 ------------------------------------------------------------ . 2177 3920 3610 3139 4112 3562 4251 5111 2559 4178 2991 3282 . G G I G H G H H G H G G . ==================================================================== . ==== C1104 1034 1965 1797 1471 2138 1794 2099 2584 1286 2200 1477 1635 1156 1741 . . . . . . . . . . . . ----- . . . . . . . . . . . . 3477 . . . . . . . . . . . . G . . . . . . . . . . . . ===== C1105 1017 1888 1723 1664 2056 1759 2115 2567 1251 2155 1375 1566 1169 1716 ----------------------------------------------------------------- 2051 3853 3520 3135 4194 3553 4214 5151 2537 4355 2852 3201 1169 G G I G H G H H G H G G B ============================================================================= C1106 1032 1913 1730 1540 2153 1756 2123 2696 1239 2141 1457 1628 1194 1739 C1107 1047 2005 1835 1551 2153 1857 2141 2681 1281 2176 1459 1668 1189 1772 ------------------------------------------------------------ . 2079 3918 3565 3091 4306 3613 4264 5377 2520 4317 2916 3296 . G G I G H G H H G H G G . ==================================================================== . ==== C1108 1041 1979 1845 1526 2165 1872 2172 2625 1381 2335 1492 1664 1199 1792 ----------------------------------------------------------------- B D I D G D G G B G B D 3582 G ============================================================================= C1109 1015 2023 1813 1454 2039 1709 2103 2557 1174 2193 1442 1607 1083 1709 C1110 1040 1983 1780 1480 2115 1805 2057 2582 1247 2237 1484 1678 1192 1745 ------------------------------------------------------------ . 2055 4006 3593 2934 4154 3514 4160 5139 2421 4430 2926 3285 . G G I G H G H H G H G G . ==================================================================== . ==== C1111 1057 1925 1839 1419 2121 1803 2166 2751 1176 2243 1507 1650 1210 1759 . . . . . . . . . . . . ----- . . . . . . . . . . . . 3485 . . . . . . . . . . . . G . . . . . . . . . . . . ===== C1112 1007 2054 1767 1525 1998 1735 2082 2636 1237 2164 1471 1617 1141 1726 ----------------------------------------------------------------- 2064 3979 3606 2944 4119 3538 4248 5387 2413 4407 2978 3267 1141 G G I G H G H H G H G G B ============================================================================= C1113 1054 1922 1839 1630 2178 1928 2170 2586 1333 2248 1547 1725 1230 1799 C1114 1093 1907 1874 1583 2225 1889 2151 2638 1327 2198 1555 1660 1243 1796 ----------------------------------------------------------------- 2147 3829 3713 3213 4403 3817 4321 5224 2660 4446 3102 3385 2473 G G I G H G H H G H G G F ============================================================================= C1115 1098 2032 1913 1593 2167 1866 2174 2802 1325 2177 1548 1709 1187 1815 ----------------------------------------------------------------- B G I D G D G G B G B D D ============================================================================= Module sizes: A ( 960 GB) Note: The storage requirement listed includes B (1440 GB) the tag-along periods for system checks D (2000 GB) and the Intensives. Actuals will thus be F (3200 GB) smaller. G (4000 GB) H (6000 GB) I (8000 GB) Notes: - Example (recording group C1109, C1110 for station TIGO): + record session C1109 on the H module and then + record session C1110 on the H module. - Suggestions for handling disk module changes are provided at the end of this document. - Tsukuba will record on K5 disks and will convert the K5 format to Mark 5B. The Mark 5B data will then be e-transfered to a server at Haystack. Haystack records data on the listed Mark 5 modules. Since there are more than 1024 scans for Tsukuba when two CONT11 days are recorded on a single module, Haystack will manage the DirList on these modules so it isn't corrupted. - In order to optimize correlator efficiency, the stations should record their data with Mark 5A or Mark 5B as follows: Bd Mark 5B Ft Mark 5A Hb Mark 5B Hh Mark 5B Kk Mark 5B Ny Mark 5B On Mark 5A Tc Mark 5B Ts Mark 5B Wf Mark 5B Wz Mark 5A Ys Mark 5B Zc Mark 5B - Ny-Alesund and Hobart will e-transfer the data of the rapid sessions (R1 and R4 equivalents: C1101, C1105, C1108, C1112, and C1115) to the Washington Correlator. The other sessions shall only be shipped via courier. Given a successful e-transfer, the modules for C1101, C1108, and C1115 can be retained at Ny-Alesund and Hobart. - Each station has at least two spare modules allocated that can be used when a regular disk fails: Bd 2G Ft 2H Hb 2G Hh 1G,1I Kk 1H,1I Ny 2G On 2H Tc 2H Ts 2G Wf 2H Wz 2G Ys 2G Zc 3D - An "extra" disk is normally inserted once recording has started on the last allocated disk for an experiment. This is done in case the the current disk fills early. Typically, this should be the module that would be inserted next if recording goes as planned. If nothing goes wrong, this will make it easy to transition to the next module/schedule. If a disk does fill early, the station will have consider how to record the end of the next experiment, since some of that experiment's module will have been used to for the current experiment. Please also see the DISK MODULE CHANGES section below. Please inform the coordinating center (ivscc@ivscc.gsfc.nasa.gov) if have a module fill prematurely. ===================================================================== Recording mode Name Code GEOSX8N 8F Recording mode setup for: BADARY FORTLEZA HARTRAO HOBART12 KOKEE NYALES20 ONSALA60 TIGOCONC TSUKUB32 WESTFORD WETTZELL YEBES40M ZELENCHK Mode Tot.Rate Tot.BandW #chan #bits Barrel Mk341:1 506.368 Mbits 253.184 MHz 14 2 NONE Chan.BW #Subpasses Tracks(*fan) Tot.tracks Speed 8.00 MHz 1 32(*1) 32 0.00 X-band spanned bw= 720.0 MHz rms spanned bw= 280.4 MHz S-band spanned bw= 140.0 MHz rms spanned bw= 50.9 MHz Effective number of channels recorded per sub-pass X S Total 19.780 11.868 31.648 ===================================================================== =================== DISK MODULE CHANGES =================== These experiments should only require one (or part of a) disk module each. Some modules will have two (or three for Zc) experiments recorded on them. Stations should follow the assigned list of module sizes according to Table 2 in these notes. DRUDG does not know the sizes, so it shows an ever-increasing GByte count in the listings. Please be aware that for the second experiment on a module, the Byte Count in the listing will not reflect the volume of data on the module from the previous experiment. Here are four suggestions for handling the changes: 1) Planning: Select the modules you will use for each experiment ahead of time using the sizes in Table 2 above as a guide. 2) Changes: After the last experiment for a module has been recorded and recording has switched to a new module, change the old module as soon as practical. You should put in the next module that is needed after the new one that is currently recording. It is good practice to change the module as soon as possible because then the FS will have a module to switch to in case the one being recorded becomes full prematurely. You should check periodically during the experiments that the modules are filling at the expected rate. If a module does fill prematurely, a window will appear prompting you to change the module. The window will give both the VSN and bank that needs to be changed. You should dismiss the window once the module has been changed. In situations where you have a module fill prematurely, you will need to make a practical decision about the next module to put in. You will at this point be recording on the rest of the current experiment on the module for the next experiment. It may be a good choice to put in a spare module that will allow you to finish recording the next experiment once the current module is full. Please be aware this may affect your plans for automated module changes and which modules will need to receive expedited shipping. Stations Ft and Wz should refer to "MARK 5 FIRMWARE ISSUES" in the section on "Special Instructions" above for more information on limitations in their usage of SATA modules and how it affects module changes. 3) Labels: Label the modules before removing then from the Mark 5, also affix a red dot. This will help avoid mixing-up the modules. At a minimum, label the module with the experiment it was used in and its sequence number. You should be able to print a label using: cd /usr2/log drudg LOG_NAME VSN where LOG_NAME is the name of the experiment log, including the ".log" and VSN is the eight character VSN. This can be done even when the FS is still writing to log during the experiment. It should be done whenever a module has been filled or a schedule has ended (in the case of a not completely filled module). This ensures that the label contains the correct complete information. The label should then be affixed promptly to help keep track of the module contents. If you are not able to print module labels and need help trouble-shooting this, please contact Ed (Ed.Himwich@nasa.gov). This issue can be worked on even after CONT11 has started. 4) Locking and unlocking: When inserting or removing a module, turn the latch to "locked" or "unlocked" only when the Mark 5 is not recording. In addition, do not turn the key to "locked" unless the FS will not be sending commands (either to setup or start recording) to the Mark 5 for at least 20 more seconds. An "unlocked" module can be safely slide in or out at anytime. If you have any questions, please contact Ed Himwich (Ed.Himwich@nasa.gov).