UNITED STATES
                  SECURITIES AND EXCHANGE COMMISSION
                       WASHINGTON, DC  20549

                           SCHEDULE 13G

              UNDER THE SECURITIES EXCHANGE ACT OF 1934

                          (AMENDMENT NO. 2)*

                      Mercury Computer Systems Inc
________________________________________________________________________
                           (Name of Issuer)

                                Common
________________________________________________________________________
                     (Title of Class of Securities)

                               589378108
________________________________________________________________________
                            (CUSIP Number)

Check the following box if a fee is being paid with this statement
[ ] . (A fee is not required only if the filing person: (1) has a
previous statement on file reporting beneficial ownership of more
than five percent of the class of securities described in Item 1;
and (2) has filed no amendment subsequent thereto reporting
beneficial ownership of five percent or less of such class.)  (See
Rule 13d-7.)

*The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect to the		
subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided		
in a prior cover page.		

The information required in the remainder of this cover page shall		
not be deemed to be filed for the purpose of Section 18 of the		
Securities Exchange Act of 1934 (Act) or otherwise subject to
the liabilities  of that section of the Act but shall be subject to		
all other provisions of the Act (however, see the Notes).





CUSIP No.  589378108           13G               Page 1 of 2 Pages
________________________________________________________________________
1        NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

         Massachusetts Mutual Life Insurance Company
         04-1590850
_________________________________________________________________________
2        CHECK THE APPROPRIATE BOX IF MEMBER OF A GROUP
                                    (A)  _______

                                    (B)  __x____
_________________________________________________________________________
3        SEC USE ONLY


_________________________________________________________________________
4        CITIZENSHIP OF PLACE OF ORGANIZATION

         Commonwealth of Massachusetts
_________________________________________________________________________
                  5        SOLE VOTING POWER
NUMBER OF
   SHARES                   351,750
                  ____________________________________________________
BENEFICIALLY      6        SHARED VOTING POWER
   OWNED BY
   EACH                    not applicable
                  ____________________________________________________
REPORTING         7        SOLE DISPOSITIVE POWER			
   PERSON			
   WITH                     351,750
                  ____________________________________________________			
                  8        SHARED DISPOSITIVE POWER			

                           not applicable			
_________________________________________________________________________			
9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING			
         PERSON			

                             351,750
_________________________________________________________________________			
10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES			
         CERTAIN SHARES *			
                       	Not applicable


_________________________________________________________________________		
11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9		

                             3.5%		
_________________________________________________________________________		
12       TYPE OF REPORTING PERSON *		

         IC  (insurance company)		
_________________________________________________________________________		

                  *  SEE INSTRUCTION BEFORE FILLING OUT!		


CUSIP No. 589378108              13G             Page 2 of 2 Pages
________________________________________________________________________
1        NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

         MassMutual Corporate Investors
         04-2483041
_________________________________________________________________________
2        CHECK THE APPROPRIATE BOX IF MEMBER OF A GROUP
                                    (A)  _______

                                    (B)  __x____
_________________________________________________________________________
3        SEC USE ONLY


_________________________________________________________________________
4        CITIZENSHIP OF PLACE OF ORGANIZATION

         Commonwealth of Massachusetts
_________________________________________________________________________
                  5        SOLE VOTING POWER
NUMBER OF
   SHARES                   285,750
                  ____________________________________________________
BENEFICIALLY      6        SHARED VOTING POWER
   OWNED BY
   EACH                    not applicable		

                  ____________________________________________________		
REPORTING         7        SOLE DISPOSITIVE POWER		
   PERSON		
   WITH                     285,750
                  ____________________________________________________		
                  8        SHARED DISPOSITIVE POWER		

                           not applicable		
_________________________________________________________________________		
9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING		
         PERSON		

                             285,750
_________________________________________________________________________
10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
         CERTAIN SHARES *

                      not applicable
_________________________________________________________________________
11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

                          2.8%
_________________________________________________________________________
12       TYPE OF REPORTING PERSON *

         IV (investment company)
_________________________________________________________________________




ITEM 1(a).  Name of Issuer: Mercury Computer Systems Inc

ITEM 1(b).  Address of Issuer's Principal Executive Offices: 

            199 Riverneck Road            
            Chelmsford, MA 01824-2820

ITEM 2(a).  Name of Person Filing:

            This statement is filed on behalf of Massachusetts   
            Mutual Life Insurance Company and MassMutual 
            Corporate Investors, which together may be
            regarded as a group for the purpose of this
            statement. This statement is signed on behalf 
            of both the aforementioned parties, and therefore
            it does not include a separate agreement
            providing for a joint filing.

ITEM 2(b).  Address of Principal Business Office:

            MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY
            1295 State Street
            Springfield, Massachusetts  01111

            MASSMUTUAL CORPORATE INVESTORS
            1295 State Street
            Springfield, Massachusetts  01111

ITEM 2(c).  Citizenship			

            MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY is			
            organized under the laws of the Commonwealth of Massachusetts			

            MASSMUTUAL CORPORATE INVESTORS is			
            organized under the laws of the Commonwealth of Massachusetts			

ITEM 2(d).  Title of Class of Securities:  Common Stock

ITEM 2(e).  CUSIP NUMBER: 589378108

ITEM 3.     This statement is filed pursuant to Rule 13d-1(b) by
            Massachusetts Mutual Life Insurance Company,
            an insurance company as defined  in Section 3(a)(19),
            MassMutual Corporate Investors, an investment
            company registered under Section 8 of the Investment
            Company Act of 1940 which together may be
            regarded as a group pursuant to  Rule
            13d-1(b) (ii) (H).

ITEM 4.     Ownership:

            This statement if filed to report information as of
            January 29, 1999:

            (a)  Amount Beneficially Owned:

            Massachusetts Mutual Life Insurance Company and
            MassMutual Corporate Investors own respectively 
            351,750 and 285,750 shares of common stock.

            Total shares of common stock owned directly and			
            indirectly:  637,500

            The filing of this statement shall not be construed			
            as an admission that Massachusetts Mutual Life			
            Insurance Company and MassMutual Corporate Investors
            are for the purposes	of sections 13(d) and 13(g)
            of the Securities Exchange Act of 1934, the
            beneficial owners of any common stock of the issuer.		

            (b)  Percent of Class:

            Percentage of ownership is calculated as follows:

            637,500 (shares held) / 10,113,000 (shares outstanding)
                    = 6.3%

            (c)  Powers:

            Massachusetts Mutual Life Insurance Company and
            MassMutual Corporate Investors each  have sole power
            to vote or dispose of respectively 351,750
            and 285,750 shares of common stock.

ITEM 5.     Ownership of Five Percent or Less of a Class:

            Not applicable

ITEM 6.     Ownership of More Than Five Percent on Behalf
            of Another Person:

            Not applicable

ITEM 7.     Identification and Classification of the
            Subsidiary Which Acquired the Security Being
            Reported on by the Parent Holding Company:

            Note applicable

ITEM 8.     Identification and Classification of Members		
            of the Group:		

            Not applicable		


ITEM 9.     Notice of Dissolution of the Group:		

           	Not applicable	

ITEM 10.    Certification:		

            By signing below, MASSACHUSETTS MUTUAL LIFE
            INSURANCE COMPANY, MASSMUTUAL CORPORATE
            INVESTORS certify to the best of their
            knowledge and belief, the securities referred to
            above were acquired in the ordinary course of
            business and were not acquired for the purpose of
            and do not have the effect of changing or
            influencing the control of the issuer of such
            securities and were not acquired in connection
            with or as a participant in any transaction having
            such purpose or effect.

            After reasonable inquiry and to the best of our
            knowledge and belief, MASSACHUSETTS MUTUTAL LIFE INSURANCE
            COMPANY and MASSMUTUAL CORPORATE INVESTORS
            certify that the information set forth in this
            statement is true, complete and correct.


February 1, 1999                      February 1, 1999
_____________________               _____________________
     Date                                Date

MASSACHUSETTS MUTUAL                MASSMUTUAL CORPORATE
LIFE INSURANCE COMPANY              INVESTORS

By:  signature                      By:  signature


Charles McCobb                      Charles McCobb
Managing Director                   Managing Director
_________________________           _________________________
(Print Name and Title               (Print Name and Title
 of Person Signing)                  of Person Signing)