Thermal-vacuum test

Qualification of the battery includes the same type of tests performed on cells plus some thermal-vacuum tests to simulate space environment, and safety test. 

ESA PSS-01-702 A Thermal Vacuum Test for the Screening of Space Materials. 

Environmental validation programs are tests performed to verify adequate workmanship in the construction of a test item. It is often necessary to impose stresses beyond those predicted for the mission in order to uncover defects. Thus, random vibration tests are conducted specifically to detect bad solder joints, loose or missing fasteners, improperly mounted parts, and so on. Cycling between temperature extremes during thermal-vacuum testing and the presence of EMI during EMC testing can also reveal the lack of proper construction and adequate workmanship. 

Thermal-vacuum test is a test conducted to demonstrate the capability of the test item to operate satisfactorily in vacuum at temperatures based on those... 

Thermal-vacuum testing of the QM would serve as the certification for the subsequent flight reactor. This was due to the risk associated with subjecting the flight reactor to environmental contaminants during the thermal-vacuum test with no subsequent means to verify the absence of material degradation,... 

O2NO).CH.CHj.N(N02) mw 251.12, N 27.89% OB to C02 minus 15-9% solid mp 112—113° was prepd by nitrating with fuming nitric acid in the presence of acetic anhydride at below 15°, the product obtd by condensing (on heating) urea, C0(NH2)2. with 1,3-di amino-2-propanol, H2N.CH2.CH(OH).CH2.NH2. It is a very powerful expl (Trauzl Test Value = 135% PA), comparable in Impact Sensitivity to Tetryl (FI Value = 60% PA), but of unsatisfactory Thermal Stability (99° Heat Test 3 minutes 100° Vacuum Test — more than 15cc in less than 16 hrs). It is hydrolyzed by water. See Refs 2 3 Refs 1) A.H. Blatt, OSRD Rept 2014(1944) 2) A.F. McKay D.F. Manchester, JACS 71, 1972(1949) CA 43, 9065(1949) 3) A.F. 

The second point is to always run tests on representative samples. Table IV illustrates this point. Original thermal stability tests were run on an alpha-oximino ester intermediate product that had been isolated by adding water to the reaction mixture, extracting the oil layer that forms with methylene chloride, and removing the methylene chloride by vacuum distillation (labelled pure oil). Later in process development it was decided to eliminate the methylene chloride extraction and separate the oil from the water layer (labelled crude oil) If repeat safety tests had not been run, the thermal stability hazard of this compound might never have been realized, and the compound might have been improperly stored or handled at too high a temperature. 

The last batch of ONBALD super crude was produced eight months before the incident. It was stored in mild steel drums outside the plant. When it was decided to distil the ONBALD super cmde, samples were sent to the laboratory for thermal stability tests using a new thermal stability test apparatus. All seemed well, so permission was given for the distillation to begin. Finally the temperature was taken up slowly, by steam heating, to 405 K. The steam was then turned off, but the temperature continued to rise and the vacuum was... 

Standard cell qualification tests include functional checkout (operational electrical test, life cycle tests), environmental tests (i.e. vibration, thermal shocks, thermal vacuum, radiation) or others as deemed appropriate for the specific hardware and application such as abuse and safety testing. Recommended test items of the component cell qualification for space vehicles are specified in ISO WD17546 ... 

Figure 5. (a) Test setup for Thermal Vacuum and calorimetric tests, (b) Typical results. Black curve labeled Fmissivity is calculated Emittance based on... 

Thermal creep is a potential factor which can determine the upper operation limit of V-alloys. Signihcant difference in the creep strain rate between the tests in vacuum and liquid Li environments was reported as shown in Fig. 11.10 [23,24]. A potential reason for the difference is N pick-up from liquid Li, resulting in hardening and reduction of the creep rate. The hgure also shows no minimum strain rate, namely absence of the primary creep regime, which is a characteristic of the thermal creep performance of V-alloys. Unfortunately, identical thermal creep tests are not available in He or Na environments. There were thermal creep data in Na but at much lower temperature (600°C) [25], because the purpose of the study was to compare with irradiation creep which becomes a problem at much lower temperature than that for the thermal creep. 

Three kinds of TiC-coated Mo specimens were tested using the thermal shock test apparatus just mentioned, namely TiC directly coated Mo (TiC/Mo), TiC-coated Mo precoated with a thin W layer (TiC/W/Mo), and TiC-coated vacuum-heat-treated Mo with a W intermediate layer (TiC/HT-W/Mo). High heat flux was 5.3 kW/cm and the heat duration was 1.5 s. 

In any leaf test program there is always a question as to what vacuum level should be used. With very porous materials, a vacuum in the range of 0.1 to 0.3 bar (3 to 9 in Hg) should be used, and, except for thermal-drying apphcations using hot air, the vacuum level should be adjusted to give an air rate in the range of 450 to 900 mVm h (30 to 40 cfm/ft measured at the vacuum. 

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