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  <xsd:element id="astc_ImpairmentLongLivedAssetHeldForUseStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" name="ImpairmentLongLivedAssetHeldForUseStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" nillable="true" substitutionGroup="xbrli:item" type="xbrli:booleanItemType" xbrli:periodType="duration"/>
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  <xsd:element id="astc_NumberofLeasedWhollyOwnedSubsidiaries" name="NumberofLeasedWhollyOwnedSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant"/>
  <xsd:element id="astc_NumberofPatentsGranted" name="NumberofPatentsGranted" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant"/>
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  <xsd:element id="astc_ScheduleofBalanceSheetPresentationofOperatingandFinanceLeasesTableTextBlock" name="ScheduleofBalanceSheetPresentationofOperatingandFinanceLeasesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
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  <xsd:element id="astc_TaxCutsAndJobsActOf2017LimitsOnUtilizationOfNetOperatingLossToTaxableIncomePercentage" name="TaxCutsAndJobsActOf2017LimitsOnUtilizationOfNetOperatingLossToTaxableIncomePercentage" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="astc_statement-statement-note-2-summary-of-significant-accounting-policies-schedule-of-contract-liabilities-details" name="statement-statement-note-2-summary-of-significant-accounting-policies-schedule-of-contract-liabilities-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="astc_statement-statement-note-2-summary-of-significant-accounting-policies-summary-of-warranty-provision-details" name="statement-statement-note-2-summary-of-significant-accounting-policies-summary-of-warranty-provision-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-2-summary-of-significant-accounting-policies-tables" name="statement-statement-note-2-summary-of-significant-accounting-policies-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-3-investments-schedule-of-investments-details" name="statement-statement-note-3-investments-schedule-of-investments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-3-investments-tables" name="statement-statement-note-3-investments-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-4-leases-schedule-of-balance-sheet-presentation-of-operating-and-finance-leases-details" name="statement-statement-note-4-leases-schedule-of-balance-sheet-presentation-of-operating-and-finance-leases-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-4-leases-schedule-of-balance-sheet-presentation-of-operating-and-finance-leases-details-parentheticals" name="statement-statement-note-4-leases-schedule-of-balance-sheet-presentation-of-operating-and-finance-leases-details-parentheticals" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-4-leases-schedule-of-future-minimum-lease-payments-details" name="statement-statement-note-4-leases-schedule-of-future-minimum-lease-payments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-4-leases-schedule-of-other-information-details" name="statement-statement-note-4-leases-schedule-of-other-information-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-4-leases-tables" name="statement-statement-note-4-leases-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-5-property-and-equipment-net-tables" name="statement-statement-note-5-property-and-equipment-net-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-5-property-and-equipment-schedule-of-property-and-equipment-details" name="statement-statement-note-5-property-and-equipment-schedule-of-property-and-equipment-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-6-fair-value-measurement-schedule-of-fair-value-measurement-of-financial-instruments-details" name="statement-statement-note-6-fair-value-measurement-schedule-of-fair-value-measurement-of-financial-instruments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-6-fair-value-measurement-tables" name="statement-statement-note-6-fair-value-measurement-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-7-stockholders-equity-schedule-of-warrant-activity-details" name="statement-statement-note-7-stockholders-equity-schedule-of-warrant-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-7-stockholders-equity-tables" name="statement-statement-note-7-stockholders-equity-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-compensation-restricted-stock-activity-details" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-compensation-restricted-stock-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-schedule-of-sharebased-compensation-expense-2-details" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-schedule-of-sharebased-compensation-expense-2-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-schedule-of-sharebased-compensation-expense-details" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-schedule-of-sharebased-compensation-expense-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-schedule-of-sharebased-compensation-fair-value-details" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-schedule-of-sharebased-compensation-fair-value-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-stock-option-activity-summary-details" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-stock-option-activity-summary-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-stock-options-outstanding-details" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-stock-options-outstanding-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-tables" name="statement-statement-note-9-common-stock-incentive-stock-purchase-plans-and-other-compensation-plans-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="astc_statement-statement-significant-accounting-policies-policies" name="statement-statement-significant-accounting-policies-policies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
</xsd:schema>
