<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:hspo="http://hspo.com/20260420"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:us-gaap="http://fasb.org/us-gaap/2025"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="hspo-20260420.xsd" xlink:type="simple"/>
    <context id="From2026-04-20to2026-04-20">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001946021</identifier>
        </entity>
        <period>
            <startDate>2026-04-20</startDate>
            <endDate>2026-04-20</endDate>
        </period>
    </context>
    <context id="From2026-04-20to2026-04-20_hspo_UnitConsistingOfOneOrdinarySharesMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001946021</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">hspo:UnitConsistingOfOneOrdinarySharesMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-04-20</startDate>
            <endDate>2026-04-20</endDate>
        </period>
    </context>
    <context id="From2026-04-20to2026-04-20_hspo_OrdinarySharesMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001946021</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">hspo:OrdinarySharesMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-04-20</startDate>
            <endDate>2026-04-20</endDate>
        </period>
    </context>
    <context id="From2026-04-20to2026-04-20_hspo_RedeemableWarrantsMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001946021</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">hspo:RedeemableWarrantsMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-04-20</startDate>
            <endDate>2026-04-20</endDate>
        </period>
    </context>
    <context id="From2026-04-20to2026-04-20_hspo_RightsEachWholeRightToAcquireMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001946021</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">hspo:RightsEachWholeRightToAcquireMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-04-20</startDate>
            <endDate>2026-04-20</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey contextRef="From2026-04-20to2026-04-20" id="ixv-456">0001946021</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag contextRef="From2026-04-20to2026-04-20" id="ixv-457">false</dei:AmendmentFlag>
    <dei:CurrentFiscalYearEndDate contextRef="From2026-04-20to2026-04-20" id="ixv-458">--12-31</dei:CurrentFiscalYearEndDate>
    <dei:DocumentType contextRef="From2026-04-20to2026-04-20" id="ixv-510">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate contextRef="From2026-04-20to2026-04-20" id="ixv-511">2026-04-20</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName contextRef="From2026-04-20to2026-04-20" id="ixv-512">HORIZON SPACE ACQUISITION I CORP.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode contextRef="From2026-04-20to2026-04-20" id="ixv-513">E9</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber contextRef="From2026-04-20to2026-04-20" id="ixv-514">001-41578</dei:EntityFileNumber>
    <dei:EntityAddressAddressLine1 contextRef="From2026-04-20to2026-04-20" id="ixv-515">1412 Broadway</dei:EntityAddressAddressLine1>
    <dei:EntityAddressAddressLine2 contextRef="From2026-04-20to2026-04-20" id="ixv-516">21st Floor</dei:EntityAddressAddressLine2>
    <dei:EntityAddressAddressLine3 contextRef="From2026-04-20to2026-04-20" id="ixv-517">Suite 21V</dei:EntityAddressAddressLine3>
    <dei:EntityAddressCityOrTown contextRef="From2026-04-20to2026-04-20" id="ixv-518">New York</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince contextRef="From2026-04-20to2026-04-20" id="ixv-519">NY</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode contextRef="From2026-04-20to2026-04-20" id="ixv-520">10018</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode contextRef="From2026-04-20to2026-04-20" id="ixv-521">646</dei:CityAreaCode>
    <dei:LocalPhoneNumber contextRef="From2026-04-20to2026-04-20" id="ixv-522">257-5537</dei:LocalPhoneNumber>
    <dei:WrittenCommunications contextRef="From2026-04-20to2026-04-20" id="ixv-523">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial contextRef="From2026-04-20to2026-04-20" id="ixv-524">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer contextRef="From2026-04-20to2026-04-20" id="ixv-525">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer contextRef="From2026-04-20to2026-04-20" id="ixv-526">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="From2026-04-20to2026-04-20_hspo_UnitConsistingOfOneOrdinarySharesMember"
      id="aid_1_0">Units, consisting of one Ordinary Share, $0.0001 par value</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="From2026-04-20to2026-04-20_hspo_UnitConsistingOfOneOrdinarySharesMember"
      id="aid_1_1">HSPUF</dei:TradingSymbol>
    <dei:Security12bTitle
      contextRef="From2026-04-20to2026-04-20_hspo_OrdinarySharesMember"
      id="aid_2_0">Ordinary Shares, par value $0.0001 per share</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="From2026-04-20to2026-04-20_hspo_OrdinarySharesMember"
      id="aid_2_1">HSPOF</dei:TradingSymbol>
    <dei:Security12bTitle
      contextRef="From2026-04-20to2026-04-20_hspo_RedeemableWarrantsMember"
      id="aid_3_0">Redeemable Warrants, each whole warrant exercisable for one Ordinary Share at an exercise price of $11.50</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="From2026-04-20to2026-04-20_hspo_RedeemableWarrantsMember"
      id="aid_3_1">HSPWF</dei:TradingSymbol>
    <dei:Security12bTitle
      contextRef="From2026-04-20to2026-04-20_hspo_RightsEachWholeRightToAcquireMember"
      id="aid_4_0">Rights, each whole right to acquire one-tenth of one Ordinary Share</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="From2026-04-20to2026-04-20_hspo_RightsEachWholeRightToAcquireMember"
      id="aid_4_1">HSPRF</dei:TradingSymbol>
    <dei:EntityEmergingGrowthCompany contextRef="From2026-04-20to2026-04-20" id="ixv-535">true</dei:EntityEmergingGrowthCompany>
    <dei:EntityExTransitionPeriod contextRef="From2026-04-20to2026-04-20" id="ixv-536">false</dei:EntityExTransitionPeriod>
</xbrl>