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        <link:definition>9952158 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES</link:definition>
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        <link:definition>9952159 - Disclosure - REVENUE RECOGNITION</link:definition>
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        <link:definition>9952160 - Disclosure - ACCOUNTS RECEIVABLE, NET</link:definition>
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        <link:definition>9952162 - Disclosure - PROPERTY AND EQUIPMENT, NET</link:definition>
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        <link:definition>9952164 - Disclosure - INTANGIBLE ASSETS, NET</link:definition>
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        <link:definition>9952166 - Disclosure - REVOLVING CREDIT FACILITY</link:definition>
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        <link:definition>9952167 - Disclosure - STOCK-BASED COMPENSATION</link:definition>
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        <link:definition>9952168 - Disclosure - SHARE REPURCHASES</link:definition>
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        <link:definition>9952170 - Disclosure - LOSS PER SHARE</link:definition>
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        <link:definition>9952171 - Disclosure - SEGMENT INFORMATION</link:definition>
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        <link:definition>9952172 - Disclosure - COMMITMENTS AND CONTINGENCIES</link:definition>
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        <link:definition>9952173 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION</link:definition>
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        <link:definition>9955511 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Policies)</link:definition>
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        <link:definition>9955512 - Disclosure - REVENUE RECOGNITION (Tables)</link:definition>
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      <link:roleType id="ACCOUNTSRECEIVABLENETTables" roleURI="http://telos.com/role/ACCOUNTSRECEIVABLENETTables">
        <link:definition>9955513 - Disclosure - ACCOUNTS RECEIVABLE, NET (Tables)</link:definition>
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        <link:definition>9955514 - Disclosure - INVENTORIES, NET (Tables)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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        <link:definition>9955515 - Disclosure - PROPERTY AND EQUIPMENT, NET (Tables)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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        <link:definition>9955516 - Disclosure - INTANGIBLE ASSETS, NET (Tables)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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        <link:definition>9955517 - Disclosure - OTHER BALANCE SHEET COMPONENTS (Tables)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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        <link:definition>9955518 - Disclosure - STOCK-BASED COMPENSATION (Tables)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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        <link:definition>9955519 - Disclosure - SHARE REPURCHASES (Tables)</link:definition>
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        <link:definition>9955520 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="LOSSPERSHARETables" roleURI="http://telos.com/role/LOSSPERSHARETables">
        <link:definition>9955521 - Disclosure - LOSS PER SHARE (Tables)</link:definition>
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      <link:roleType id="SEGMENTINFORMATIONTables" roleURI="http://telos.com/role/SEGMENTINFORMATIONTables">
        <link:definition>9955522 - Disclosure - SEGMENT INFORMATION (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
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        <link:definition>9955523 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION (Tables)</link:definition>
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        <link:definition>9955524 - Disclosure - ORGANIZATION - Narrative (Details)</link:definition>
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        <link:definition>9955525 - Disclosure - REVENUE RECOGNITION - Narrative (Details)</link:definition>
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        <link:definition>9955525 - Disclosure - REVENUE RECOGNITION - Narrative (Details)</link:definition>
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        <link:definition>9955526 - Disclosure - REVENUE RECOGNITION - Disaggregation of Revenue (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="REVENUERECOGNITIONScheduleofContractBalancesDetails" roleURI="http://telos.com/role/REVENUERECOGNITIONScheduleofContractBalancesDetails">
        <link:definition>9955527 - Disclosure - REVENUE RECOGNITION - Schedule of Contract Balances (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType id="ACCOUNTSRECEIVABLENETDetails" roleURI="http://telos.com/role/ACCOUNTSRECEIVABLENETDetails">
        <link:definition>9955528 - Disclosure - ACCOUNTS RECEIVABLE, NET (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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        <link:definition>9955529 - Disclosure - ACCOUNTS RECEIVABLE, NET - Narrative (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESNETDetails" roleURI="http://telos.com/role/INVENTORIESNETDetails">
        <link:definition>9955530 - Disclosure - INVENTORIES, NET (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType id="PROPERTYANDEQUIPMENTNETPropertyPlantandEquipmentDetails" roleURI="http://telos.com/role/PROPERTYANDEQUIPMENTNETPropertyPlantandEquipmentDetails">
        <link:definition>9955531 - Disclosure - PROPERTY AND EQUIPMENT, NET - Property, Plant and Equipment (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType id="GOODWILLDetails" roleURI="http://telos.com/role/GOODWILLDetails">
        <link:definition>9955532 - Disclosure - GOODWILL (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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        <link:definition>9955533 - Disclosure - INTANGIBLE ASSETS, NET - Finite-Lived Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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        <link:definition>9955533 - Disclosure - INTANGIBLE ASSETS, NET - Finite-Lived Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType id="INTANGIBLEASSETSNETAmortizationExpenseDetails" roleURI="http://telos.com/role/INTANGIBLEASSETSNETAmortizationExpenseDetails">
        <link:definition>9955534 - Disclosure - INTANGIBLE ASSETS, NET - Amortization Expense (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType id="OTHERBALANCESHEETCOMPONENTSOtherAssetsDetails" roleURI="http://telos.com/role/OTHERBALANCESHEETCOMPONENTSOtherAssetsDetails">
        <link:definition>9955535 - Disclosure - OTHER BALANCE SHEET COMPONENTS - Other Assets (Details)</link:definition>
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        <link:definition>9955536 - Disclosure - OTHER BALANCE SHEET COMPONENTS - Accounts Payable and Other Accrued Liabilities (Details)</link:definition>
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      <link:roleType id="OTHERBALANCESHEETCOMPONENTSOtherCurrentLiabilitiesDetails" roleURI="http://telos.com/role/OTHERBALANCESHEETCOMPONENTSOtherCurrentLiabilitiesDetails">
        <link:definition>9955537 - Disclosure - OTHER BALANCE SHEET COMPONENTS - Other Current Liabilities (Details)</link:definition>
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      <link:roleType id="REVOLVINGCREDITFACILITYDetails" roleURI="http://telos.com/role/REVOLVINGCREDITFACILITYDetails">
        <link:definition>9955538 - Disclosure - REVOLVING CREDIT FACILITY (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="STOCKBASEDCOMPENSATIONNarrativeDetails" roleURI="http://telos.com/role/STOCKBASEDCOMPENSATIONNarrativeDetails">
        <link:definition>9955539 - Disclosure - STOCK-BASED COMPENSATION - Narrative (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="STOCKBASEDCOMPENSATIONStockBasedCompensationExpenseIncurredDetails" roleURI="http://telos.com/role/STOCKBASEDCOMPENSATIONStockBasedCompensationExpenseIncurredDetails">
        <link:definition>9955540 - Disclosure - STOCK-BASED COMPENSATION - Stock-Based Compensation Expense Incurred (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="STOCKBASEDCOMPENSATIONNonvestedRestrictedStockUnitsActivityDetails" roleURI="http://telos.com/role/STOCKBASEDCOMPENSATIONNonvestedRestrictedStockUnitsActivityDetails">
        <link:definition>9955541 - Disclosure - STOCK-BASED COMPENSATION - Nonvested Restricted Stock Units Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="STOCKBASEDCOMPENSATIONStockOptionActivityDetails" roleURI="http://telos.com/role/STOCKBASEDCOMPENSATIONStockOptionActivityDetails">
        <link:definition>9955542 - Disclosure - STOCK-BASED COMPENSATION - Stock Option Activity (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      </link:roleType>
      <link:roleType id="SHAREREPURCHASESNarrativeDetails" roleURI="http://telos.com/role/SHAREREPURCHASESNarrativeDetails">
        <link:definition>9955543 - Disclosure - SHARE REPURCHASES - Narrative (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
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      </link:roleType>
      <link:roleType id="SHAREREPURCHASESShareRepurchasesActivityDetails" roleURI="http://telos.com/role/SHAREREPURCHASESShareRepurchasesActivityDetails">
        <link:definition>9955544 - Disclosure - SHARE REPURCHASES - Share Repurchases Activity (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails" roleURI="http://telos.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSDetails">
        <link:definition>9955545 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LOSSPERSHAREDetails" roleURI="http://telos.com/role/LOSSPERSHAREDetails">
        <link:definition>9955546 - Disclosure - LOSS PER SHARE (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONNarrativeDetails" roleURI="http://telos.com/role/SEGMENTINFORMATIONNarrativeDetails">
        <link:definition>9955547 - Disclosure - SEGMENT INFORMATION - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SEGMENTINFORMATIONOperationsbyBusinessSegmentDetails" roleURI="http://telos.com/role/SEGMENTINFORMATIONOperationsbyBusinessSegmentDetails">
        <link:definition>9955548 - Disclosure - SEGMENT INFORMATION - Operations by Business Segment (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUPPLEMENTALCASHFLOWINFORMATIONCashCashEquivalentsandRestrictedCashDetails" roleURI="http://telos.com/role/SUPPLEMENTALCASHFLOWINFORMATIONCashCashEquivalentsandRestrictedCashDetails">
        <link:definition>9955549 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - Cash, Cash Equivalents, and Restricted Cash (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUPPLEMENTALCASHFLOWINFORMATIONSupplementalCashFlowInformationDetails" roleURI="http://telos.com/role/SUPPLEMENTALCASHFLOWINFORMATIONSupplementalCashFlowInformationDetails">
        <link:definition>9955550 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - Supplemental Cash Flow Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
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  <xs:element id="tls_RevenueTimingOfTransferOfGoodsOrServiceMember" abstract="true" name="RevenueTimingOfTransferOfGoodsOrServiceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_FederalGovernmentMember" abstract="true" name="FederalGovernmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_StateLocalAndCommercialMember" abstract="true" name="StateLocalAndCommercialMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_CostPlusFixedFeeMember" abstract="true" name="CostPlusFixedFeeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_SecuritySolutionsSegmentMember" abstract="true" name="SecuritySolutionsSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_SecureNetworksSegmentMember" abstract="true" name="SecureNetworksSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_BillContractsReceivableNetOfAllowance" abstract="false" name="BillContractsReceivableNetOfAllowance" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_FurnitureAndEquipmentMember" abstract="true" name="FurnitureAndEquipmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_InProcessSoftwareDevelopmentCostsMember" abstract="true" name="InProcessSoftwareDevelopmentCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_IntangibleAssetsAmortizationExpense" abstract="false" name="IntangibleAssetsAmortizationExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_OtherAccruedExpensesCurrent" abstract="false" name="OtherAccruedExpensesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_OtherCurrentLiabilitiesOther" abstract="false" name="OtherCurrentLiabilitiesOther" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_AlternativeBaseRateMember" abstract="true" name="AlternativeBaseRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_AdjustedDailySimpleSecuredOvernightFinancingRateSOFRMember" abstract="true" name="AdjustedDailySimpleSecuredOvernightFinancingRateSOFRMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_AdjustedTermSecuredOvernightFinancingRateSOFRMember" abstract="true" name="AdjustedTermSecuredOvernightFinancingRateSOFRMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption" abstract="false" name="LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_DebtInstrumentNumberOfVariableRates" abstract="false" name="DebtInstrumentNumberOfVariableRates" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="tls_DebtInstrumentIncrementalIncreaseInInterestRateDueToDefault" abstract="false" name="DebtInstrumentIncrementalIncreaseInInterestRateDueToDefault" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="tls_DebtInstrumentPriorNoticePeriod" abstract="false" name="DebtInstrumentPriorNoticePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="tls_DebtInstrumentCovenantSeniorLeverageRatioMaximum" abstract="false" name="DebtInstrumentCovenantSeniorLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="tls_ReceivablesExcludedFromCollateral" abstract="false" name="ReceivablesExcludedFromCollateral" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_StockPriceMarketConditionsPSUsMember" abstract="true" name="StockPriceMarketConditionsPSUsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_TSRMarketConditionsPSUsMember" abstract="true" name="TSRMarketConditionsPSUsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_ContingentPerformanceShares2027TargetsMember" abstract="true" name="ContingentPerformanceShares2027TargetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_ContingentPerformanceShares2025TargetsMember" abstract="true" name="ContingentPerformanceShares2025TargetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_Two016OmnibusLongTermIncentivePlanMember" abstract="true" name="Two016OmnibusLongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardModifications" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardModifications" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="tls_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingConditionsStockPricesThresholdNumberOfConsecutiveDays" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingConditionsStockPricesThresholdNumberOfConsecutiveDays" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="tls_ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetPayoutPercentageOfSharesGranted" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetPayoutPercentageOfSharesGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="tls_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstandingExercisableAndVestedOrExpectedToVest" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstandingExercisableAndVestedOrExpectedToVest" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_ServiceBasedRSUAwardsMember" abstract="true" name="ServiceBasedRSUAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="tls_IncrementalCommonSharesExcludedFromTheDilutiveEffect" abstract="false" name="IncrementalCommonSharesExcludedFromTheDilutiveEffect" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="tls_CostShareBasedPaymentArrangementExpense" abstract="false" name="CostShareBasedPaymentArrangementExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="tls_IssuanceOfCommonStockFor401KMatch" abstract="false" name="IssuanceOfCommonStockFor401KMatch" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
