<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by DFIN XBRL Schema Document - http://www.dfinsolutions.com/ - on 27-05-2026 03:56:11 PM -->
<!-- Copyright(c) 2026 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<schema targetNamespace="http://www.blackrock.com/20260515" elementFormDefault="qualified" xmlns:fnd="http://xbrl.sec.gov/fnd-cef/2025" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:bsatt="http://www.blackrock.com/20260515" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:rr="http://xbrl.sec.gov/rr/2021" xmlns:dtr="http://www.xbrl.org/2009/dtr" xmlns:ref="http://www.xbrl.org/2006/ref" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:dei="http://xbrl.sec.gov/dei/2025" xmlns:xbrldi="http://xbrl.org/2006/xbrldi" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:cef="http://xbrl.sec.gov/cef/2025" xmlns:xlink="http://www.w3.org/1999/xlink">
    <annotation>
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                <link:roleRef roleURI="http://xbrl.sec.gov/cef/role/N2" xlink:type="simple" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#N2"/>
                <link:roleRef roleURI="http://xbrl.sec.gov/cef/role/RiskOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#RiskOnly"/>
                <link:roleRef roleURI="http://xbrl.sec.gov/cef/role/SecurityOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#SecurityOnly"/>
				<link:roleRef roleURI="http://xbrl.sec.gov/cef/role/CoregistrantOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#CoregistrantOnly"/>
				<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
				<link:presentationLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/cef/role/N2">	
					<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#cef_AllCoregistrantsMember" xlink:label="AllCoregistrantsMember"/>
					<link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain"/>
					<link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain"/>
					<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/cef/2025/cef-2025.xsd#cef_AllRisksMember" xlink:label="AllRisksMember"/>
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				<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/cef/role/CoregistrantOnly">
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				<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/cef/role/SecurityOnly">
					<link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain"/>
					<link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain"/>
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	<import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
	<import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
	<import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
	<import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd"/>
	<import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
	<import namespace="http://xbrl.sec.gov/cef/2025" schemaLocation="https://xbrl.sec.gov/cef/2025/cef-2025.xsd"/>
	<import namespace="http://xbrl.sec.gov/cef-pre/2025" schemaLocation="https://xbrl.sec.gov/cef/2025/cef-2025_pre.xsd"/>
	<import namespace="http://xbrl.sec.gov/fnd-cef-pre/2025" schemaLocation="https://xbrl.sec.gov/fnd/2025/fnd-cef-2025_pre.xsd"/>
</schema>
