Qrouno Coverage
fffMT* 2J.11 J JO SC-1 REFRIGERATION «VIT EM DATA LAUNCH » • HOURS O.E.T
Evaluation of this flight data from lift-off to approximately b hours GET indicates nominal refriqeration system performance. While the radiator plume shield jettison time could not be determined precisely from tne available fliqht data, there was verification that the M command for shield jettison was sent at the nominal prescribed t1mo (uu:0y::>7.4 ul(). Refrigeration system temperature djta indicates the shield was jettisoned at, or near this nominal time. This conclusion is based on th® following:
a. The KS bypas: valve event data U73*o) indicated a switching event froir: bypass to radiator position consistent wits the required PR CKT radiator surface temperature (C7k:'jy). and within the predicted elapsed time for a nominal shirlu jettison.
b. The slope of the PK CKT radiator surface temperature, C72y*, (Figure 2.2.11.7-22) shows a continuous uecieasinq trend to Its minimum during the first revolution, ano follows the analytical and HS-ly-1 predictions. /> snitU jettison at a time significantly later than nominal, tut before the time of minimum radiator temperature, would appear as a change in slope at tnis jettison time. This slope change did not occur. Furthermore, a change in slope would result In a radiator temperature nlstory tnal 1s Inconsistent with the actual flignt data.
c. A heat balance on the thermal capacitor from launch tu first capacitor refreeze following launch further substantiates radiator surface temperature, capacitor inlet temperature and bypass valve event data. Any sianlfleant change in slope due to a late shield jettison, or failure to jettison, would not show a heat balance based on the thermal capacitor outlet temperature, C7279, for the same time span.
It should be noted that a backup i)CS command was sent at 01:34:27 GET; however, jettisoii at this time could not have occurred based on evaluation of available data as indicated *Lovr.
On DOY 136 and 137, various vehicle maneuvers were performed in order to lower the internal OWS environment. As a result, the RS radiator was positioned toward the sun. The maximum rood freezer temperature, C7283, history is shown in Figures 2.2.11.7-31 and 2.2.11.7-32 for these periods, indicating the maximum CEI limit of 0°? (255-5°K) was not exceeded.
Prior to DOY 173, the radiator bypass valve functioned normally as described in paragraph 2.2.11.7B. This is illustrated in Figure 2.2.11.7-33 showing a typical orbital cycle of the primary loop thermal capacitor inlet temperature during the early portion of the mission. As SL-2 progressed, the OWS internal ambient temperature decreased to a stabilized value. The radiator inlet (C727>) and outlet (C7299) temperatures subsequently lowered. Consequently, the radiator "Cold Bypass" cycle decreased to one per orbit.
During SL-2 all the Z-LV (E) maneuvers were performed while the RS was coincidently in "Cold Bypass." Thus, the higher radiator heat flux due to these EREP maneuvers had no effect upon the internal RS temperatures (urine and food).
Daily RS trend data for activation, EREP maneuver sequences, and deactivation periods for SL-3 is shown on Figures 2.2.11.7-3'» through 2.2.11.7-38. During sequential EREP maneuvers, i.e., "back-to-back" EREP's within a 2U-hour period, as illustrated on Figure 2.2.11.7-36, the RS maintained temperatures within their allowable limits. The maximum food temperature rise was under 5°F (258°K) with a 20-hour recovery. For a single EREP maneuver, the maximum rise was under 3°F (257°K) with an approximate 12-hour recovery.
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