content: UNITED STATES SEC USE ONLY
  
              SECURITIES AND EXCHANGE COMMISSION DOCUMENT SEQUENCE NO.
  
                               Washington, D.C. 20549
  
                                      FORM 144
  
                        NOTICE OF PROPOSED SALE OF SECURITIES
  
                PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
  
  ATTENTION:  Transmit  for filing 3 copies of this form  concurrently  with
  either  placing  an order with a broker to execute  sale or
  executing a sale directly with a market maker
  
  1(a) NAME OF ISSUER (Please type or print) (b) IRS IDENT. NO.(c) S.E.C. FILE NO.
  
  Mercury Computer Systems, Inc.               04-2741391
                                               ----------
  
  1(d) ADDRESS OF ISSUER      STREET  CITY     STATE   ZIP CODE (e) TELEPHONE NO.
  
  199 Riverneck Road, Chelmsford, MA                   01824     (978) 256-1300
                                                       -----     --------------
  <TABLE>
  <CAPTION>
  
  2(a)NAME OF PERSON FOR WHOSE (b)SOCIAL SECURITY (c)RELATIONSHIP (d) ADDRESS       STREET              CITY       STATE   ZIP CODE
  ACCOUNT THE SECURITIES          NO. OR IRS IDENT.  TO ISSUER
  ARE TO BE SOLD                  NO.
  <S>                             <C>                <C>          <C>               <C>                 <C>        <C>       <C>
  
  James R. Bertelli                                    President                    34 Powers Road      Hollis     NH        03049
                                                       Chief
                                                       Executive
                                                       Officer
  </TABLE>
  
  INSTRUCTION:  The person filing this notice should contact the issuer to obtain
  the I.R.S. Identification Number and the S.E.C. File Number.
  <TABLE>
  <CAPTION>
  
  3(a)           (b)                SEC USE ONLY   (c)           (d)          (e)               (f)                (g)
                 ---                ------------   ---           ---          ---               ---                ---
  
  Title of the   Name and Address   Broker-Dealer  Number of     Aggregate    Number of Shares  Approximate        Name of Each
  Class of       of Each Broker     File Number    Shares or     Market       or Other Units    Date of Sale       Securities
  Securities     Through Whom the                  Other Units   Value        Outstanding       (See instr. 3(f))  Exchange
  to be Sold     Securities are                    to be Sold    See instr.   (See instr. 3(e)) (MO.  DAY YR.)     (See instr. 3(g))
                 to Offered or                     (See instr.   3(d))
                 Each Market Maker                 3(c))
                 who is Aquiring
                 the Securities
  
  <S>            <C>                <C>            <C>           <C>          <C>               <C>                <C>
  
  Common         Morgan Stanley Dean                10,000       $530,500     21.48mm           1/31/01            NASDAQ
  Stock          Witter
                 3 Copley Place, Suite 100
                 Boston, MA  02116
                 Francis J. Dietrich
  </TABLE>
  <PAGE>
  INSTRUCTIONS
  <TABLE>
  <S>                                                          <C>
  
  1. (a) Name of Issuer                                        3. (a) Title of the class of securities to be sold
     (b) Issuer's  I.R.S.  Identification Number                  (b) Name and address of each broker through whom the securities are
     (c) Issuer's  S.E.C. number, if any                              intended to be sold
     (d) Issuer's  address,  including zip code                   (c) Number  of  shares  or  other units to be sold  (if  debt
     (e) Issuer's  telephone number, including area code              including  securities, give the aggregate face amount)
                                                                  (d) Aggregate  market  value  of the  securities  to be  sold  as
  2. (a) Name of person for whose  account the  securities            of a specified date within 10 days prior to the filing of this
         are to be sold                                               notice
     (b) Such persons Social Security or I.R.S.Identification     (e) Number of shares or other units of the class  outstanding,  or
         number                                                       if debt securities the face amount  thereof  outstanding,  as
     (c) Such  person's relationship  to the  issuer  (e.g.,          shown by the most recent  report or  statement published by the
         officer, director, 10% stockholder, or member                issuer
         of immediate family of any of the foregoing)             (f) Approximate  date on which the securities are to be sold
     (d) Such person's address, including zip code                (g) Name of each securities exchange, if any, on which the
                                                                      securities  are  intended  to be sold  number
  
  </TABLE>
  
  
  
  
                                   SEC 1147 (9-93)
  
  
  <PAGE>
  
  
  
  
                           TABLE I - SECURITIES TO BE SOLD
  
      Furnish the following information with respect to the acquisition of the
    securities to be sold and with respect to the payment of all or any part of
                 the purchase price or other consideration therefor:
  <TABLE>
  <CAPTION>
                                                  Name of Person
  Title of     Date You  Nature of                from Whom Acquired            Amount of             Date of
  the Class    Acquired  Acquisition Transaction  (If gift, also give date      Securities Acquired   Payment     Nature of Payment
                                                  donor acquired)
  <S>          <C>       <C>                      <C>                           <C>                   <C>         <C>
  
  Common       1/1/83    Founders stock           Mercury Computer              800,000               N/A         N/A
  Stock                                           Systems, Inc.
  </TABLE>
  
  INSTRUCTIONS: 1. If the securities were purchased and full payment therefore was
  not  made in cash at the time of  purchase,  explain  in the  table or in a note
  thereto the nature of the consideration given. If the consideration consisted of
  any note or other  obligation,  or if payment was made in installments  describe
  the  arrangement  and state when the note or other  obligation was discharged in
  full or the last installment paid.
  
  2. If within two years after the  acquisition  of the  securities the person for
  whose account they are to be sold had any short  positions,  put or other option
  to dispose of securities  referred to in paragraph  (d)(3) of Rule 144,  furnish
  full information with respect thereto.
  <PAGE>
            TABLE II - SECURITIES SOLD DURING THE PAST 3 MONTHS TABLE II
  
  Furnish the following information as to all securities of the issuer sold during
  the past 3 months by the person for whose account the securities are to be sold.
  <TABLE>
  <CAPTION>
  
                                                                                           Amount of       Gross
  Name and Address of Seller              Title of Securities Sold        Date of Sale     Securities      Proceeds
  <S>                                     <C>                             <C>              <C>             <C>
  
  James R. Bertelli                       Mercury Computer                1/30/01          10,000          520,730.27
  34 Powers Road                          Systems, Inc.
  Hollis, NH  03049
  </TABLE>
  
  REMARKS:
  
  <TABLE>
  <S>                                                                                <C>
  
  <PAGE>
  
  INSTRUCTIONS:                                                                      ATTENTION:
  See the  definition  of "person" in paragraph  (a) of Rule 144.  Information       The person for whose  account  the  securities
  is to be given not only as to the person for whose account the securities          to which this notice relates are to be sold
  are to be sold but also as to all other peresons included in the definition.       hereby represents by signing this notice that he
  In addition, information shall be given as to sales by all persons whose           does not know any material adverse information
  sales are required by paragraph (e) of Rule 144 to be aggregated with sales        in regard to the current and prospective
  for the account of the person filing this notice.                                  operations of the Issuer of the securities to be
                                                                                     sole which has not been publicly disclosed.
  
  
                       01/31/01                                                       /s/ James R. Bertelli by
                    (DATE OF NOTICE)                                                      Anthony J. Medaglia, Jr., atty
                                                                                           (SIGNATURE)
  </TABLE>
  
  
  The notice shall be signed by the person for whose account the securities are to
   be sold. At least one copy of the notice shall be manually signed. Any copies
            not manually signed shall bear typed or printed signatures.
  
  ATTENTION:  Intentional  misstatements or omission of facts  constitute
  Federal Criminal Violations (See 18 U.S.C. 1001).
metadata_documents: [{"type": "144", "sequence": "1", "filename": "0001.txt", "description": "FORM 144", "secsgml_size_bytes": 9304}]
text: UNITED STATES SEC USE ONLY
  
              SECURITIES AND EXCHANGE COMMISSION DOCUMENT SEQUENCE NO.
  
                               Washington, D.C. 20549
  
                                      FORM 144
  
                        NOTICE OF PROPOSED SALE OF SECURITIES
  
                PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
  
  ATTENTION:  Transmit  for filing 3 copies of this form  concurrently  with
  either  placing  an order with a broker to execute  sale or
  executing a sale directly with a market maker
  
  1(a) NAME OF ISSUER (Please type or print) (b) IRS IDENT. NO.(c) S.E.C. FILE NO.
  
  Mercury Computer Systems, Inc.               04-2741391
                                               ----------
  
  1(d) ADDRESS OF ISSUER      STREET  CITY     STATE   ZIP CODE (e) TELEPHONE NO.
  
  199 Riverneck Road, Chelmsford, MA                   01824     (978) 256-1300
                                                       -----     --------------
  2(a)NAME OF PERSON FOR WHOSE (b)SOCIAL SECURITY (c)RELATIONSHIP (d) ADDRESS       STREET              CITY       STATE   ZIP CODE
  ACCOUNT THE SECURITIES          NO. OR IRS IDENT.  TO ISSUER
  ARE TO BE SOLD                  NO.
  James R. Bertelli                                    President                    34 Powers Road      Hollis     NH        03049
                                                       Chief
                                                       Executive
                                                       Officer
  INSTRUCTION:  The person filing this notice should contact the issuer to obtain
  the I.R.S. Identification Number and the S.E.C. File Number.
  3(a)           (b)                SEC USE ONLY   (c)           (d)          (e)               (f)                (g)
                 ---                ------------   ---           ---          ---               ---                ---
  
  Title of the   Name and Address   Broker-Dealer  Number of     Aggregate    Number of Shares  Approximate        Name of Each
  Class of       of Each Broker     File Number    Shares or     Market       or Other Units    Date of Sale       Securities
  Securities     Through Whom the                  Other Units   Value        Outstanding       (See instr. 3(f))  Exchange
  to be Sold     Securities are                    to be Sold    See instr.   (See instr. 3(e)) (MO.  DAY YR.)     (See instr. 3(g))
                 to Offered or                     (See instr.   3(d))
                 Each Market Maker                 3(c))
                 who is Aquiring
                 the Securities
  Common         Morgan Stanley Dean                10,000       $530,500     21.48mm           1/31/01            NASDAQ
  Stock          Witter
                 3 Copley Place, Suite 100
                 Boston, MA  02116
                 Francis J. Dietrich
  INSTRUCTIONS
  1. (a) Name of Issuer                                        3. (a) Title of the class of securities to be sold
     (b) Issuer's  I.R.S.  Identification Number                  (b) Name and address of each broker through whom the securities are
     (c) Issuer's  S.E.C. number, if any                              intended to be sold
     (d) Issuer's  address,  including zip code                   (c) Number  of  shares  or  other units to be sold  (if  debt
     (e) Issuer's  telephone number, including area code              including  securities, give the aggregate face amount)
                                                                  (d) Aggregate  market  value  of the  securities  to be  sold  as
  2. (a) Name of person for whose  account the  securities            of a specified date within 10 days prior to the filing of this
         are to be sold                                               notice
     (b) Such persons Social Security or I.R.S.Identification     (e) Number of shares or other units of the class  outstanding,  or
         number                                                       if debt securities the face amount  thereof  outstanding,  as
     (c) Such  person's relationship  to the  issuer  (e.g.,          shown by the most recent  report or  statement published by the
         officer, director, 10% stockholder, or member                issuer
         of immediate family of any of the foregoing)             (f) Approximate  date on which the securities are to be sold
     (d) Such person's address, including zip code                (g) Name of each securities exchange, if any, on which the
                                                                      securities  are  intended  to be sold  number
  SEC 1147 (9-93)
  TABLE I - SECURITIES TO BE SOLD
  
      Furnish the following information with respect to the acquisition of the
    securities to be sold and with respect to the payment of all or any part of
                 the purchase price or other consideration therefor:
  Name of Person
  Title of     Date You  Nature of                from Whom Acquired            Amount of             Date of
  the Class    Acquired  Acquisition Transaction  (If gift, also give date      Securities Acquired   Payment     Nature of Payment
                                                  donor acquired)
  Common       1/1/83    Founders stock           Mercury Computer              800,000               N/A         N/A
  Stock                                           Systems, Inc.
  INSTRUCTIONS: 1. If the securities were purchased and full payment therefore was
  not  made in cash at the time of  purchase,  explain  in the  table or in a note
  thereto the nature of the consideration given. If the consideration consisted of
  any note or other  obligation,  or if payment was made in installments  describe
  the  arrangement  and state when the note or other  obligation was discharged in
  full or the last installment paid.
  
  2. If within two years after the  acquisition  of the  securities the person for
  whose account they are to be sold had any short  positions,  put or other option
  to dispose of securities  referred to in paragraph  (d)(3) of Rule 144,  furnish
  full information with respect thereto.
  TABLE II - SECURITIES SOLD DURING THE PAST 3 MONTHS TABLE II
  
  Furnish the following information as to all securities of the issuer sold during
  the past 3 months by the person for whose account the securities are to be sold.
  Amount of       Gross
  Name and Address of Seller              Title of Securities Sold        Date of Sale     Securities      Proceeds
  James R. Bertelli                       Mercury Computer                1/30/01          10,000          520,730.27
  34 Powers Road                          Systems, Inc.
  Hollis, NH  03049
  REMARKS:
  INSTRUCTIONS:                                                                      ATTENTION:
  See the  definition  of "person" in paragraph  (a) of Rule 144.  Information       The person for whose  account  the  securities
  is to be given not only as to the person for whose account the securities          to which this notice relates are to be sold
  are to be sold but also as to all other peresons included in the definition.       hereby represents by signing this notice that he
  In addition, information shall be given as to sales by all persons whose           does not know any material adverse information
  sales are required by paragraph (e) of Rule 144 to be aggregated with sales        in regard to the current and prospective
  for the account of the person filing this notice.                                  operations of the Issuer of the securities to be
                                                                                     sole which has not been publicly disclosed.
  
                       01/31/01                                                       /s/ James R. Bertelli by
                    (DATE OF NOTICE)                                                      Anthony J. Medaglia, Jr., atty
                                                                                           (SIGNATURE)
  The notice shall be signed by the person for whose account the securities are to
   be sold. At least one copy of the notice shall be manually signed. Any copies
            not manually signed shall bear typed or printed signatures.
  
  ATTENTION:  Intentional  misstatements or omission of facts  constitute
  Federal Criminal Violations (See 18 U.S.C. 1001).