<PAGE>

                                                                   Exhibit 10.53

                              SUBLEASE AGREEMENT
                              ------------------

     THIS SUBLEASE AGREEMENT is made and entered into effective this 16th day of
October 1992 by and between LORAL INFRARED & IMAGING SYSTEMS, INC., a Delaware
corporation and a subsidiary of Loral Corporation, with its principal place of
business at 600 Third Avenue, New York, New York 10016 (hereinafter referred to
as "Sublessor") and STRATUS COMPUTER, INC., a Massachusetts corporation, with
its principal office at 55 Fairbanks Boulevard, Marlboro, Massachusetts 01752
(hereinafter referred to as "Sublessee").

                                  ARTICLE ONE
                                  -----------
                                  References
                                  ----------

     1.1.  Definitions.  As used in this Sublease, the following terms shall
           -----------
have the following meanings:

          A.  "Master Lease" shall mean that lease dated December 18, 1986, with
              --------------
James A. Progin and Peter M. Small, as Trustees of 401 Elm Street Realty Trust,
as Landlord, and Honeywell, Inc., a Delaware corporation, as Tenant, as such
lease was amended by that, First Amendment to-Lease dated November 17, 1988 and
which lease as so amended was assigned by Honeywell, Inc. to-Loral Corporation
and simultaneously assigned by Loral Corporation to Sublessor by those
Assignments and Assumptions of Lease effective December 31, 1999, and which
lease, First Amendment and Assignments and Assumptions are attached hereto as
Exhibit C.

          B.  "Master Landlord" shall mean the Landlord named in paragraph A of
              -----------------
this Section 1.1 or any successor to such named Landlord which shall be the
Landlord under the Master Lease.

          C.  "Development Agreement" shall mean that certain Agreement between
              -----------------------
Master Landlord and Honeywell, Inc. dated December 18, 1986 pertaining to that
certain
<PAGE>

unimproved land adjacent to that covered by the Master Lease and defined
as the "Unimproved Land" in paragraph E of this Section 1.1, a copy of which has
been given to Sublessee and receipt of which Sublessee acknowledges.

          D.  "Lot 1" shall mean that certain parcel of land containing
              -------
approximately 12.473 acres designated as "Lot 1" on that subdivision plan
entitled "Honeywell Park, Marlborough, MA, November 14, 1988, A Definitive
Subdivision of Land, by H. W. Moore Associates, Inc. recorded with the Middlesex
South Registry of Deeds in Book 19938, Page 221.

          E.  "Unimproved Property" shall mean that certain parcel of land
              ---------------------
containing approximately 23.996 acres designated as "Lot 2" on the subdivision
plan referred to in paragraph D of this Section 1.1.

          F.  "Premises" shall mean Lot 1 .and all of the improvements located
              ----------
thereon, excluding the portion, thereof covered by that certain lease between
Master Landlord and the Marlboro Historical Society dated July 1, 1981, a copy
of Which is included in Exhibit B.

          G.  "Building" shall mean the two level building located on Lot 1
              ----------
containing approximately 126,000 square feet of floor area as shown on Plan I
and Plan 2 attached as Exhibit A.

          H.  "Common Areas" shall mean all of the area of the Premises outside
              --------------
of the Building and including the paved access and parking and all landscaped
areas.

          I.  "Maverick Production Area" shall mean that space on Plan 1 of
              --------------------------
Exhibit A shaded and labeled as "Maverick Production" and containing
approximately 8,800 square feet of floor area.

          J.  OMITTED INTENTIONALLY.

          K.  "Term Commencement Date" shall mean September 1, 1992.
              ------------------------

                                      -9-
<PAGE>

          L.  "Term" shall mean the term of this Sublease which shall commence
              ------
on the Term Commencement Date and end on March 31, 1998 unless extended pursuant
to Sections 2.3 or 2.4 or sooner terminated pursuant to the provisions of this
Sublease.

          M.  "Initial Term" shall mean the period of the Term commencing on the
              --------------
Term Commencement Date and ending on March 31, 1998 unless sooner terminated
pursuant to the provisions of this Sublease.

          N.  "First Extended Term" shall mean the period of the Term if
              ---------------------
extended pursuant to Section 2.3 commencing on April 1, 1998 and ending on March
31, 2003 unless sooner terminated pursuant to the provisions of this Sublease.

          O.  "Second Extended Term" shall.-mean the period of the Term if
              ----------------------
extended pursuant to Section 2.4 commencing on April 1, 2003 and ending on
November 30, 2006 unless sooner terminated pursuant to the provisions of this
Sublease.

          P.  "Rent Commencement Date" shall mean April 1, 1993.
              ------------------------

          Q.  "Fixed Rent" shall mean the rent specified in Section 5.1 as
              ------------
payable during the Initial Term and shall mean the rent determined pursuant to
Section 5.2 during the First Extended Term and the rent determined pursuant to
Section 5.3 during the Second Extended Term.

          R.  "Additional Rent" shall mean all other payments which Sublessee is
              -----------------
obligated to make under this Sublease in addition to Fixed Rent.

          S.  "Laws" shall mean all federal, state, county and local laws,
              ------
statutes and codes applicable to the Premises, the regulations adopted and
publications promulgated pursuant thereto and the regulations and directives of
all authorities having jurisdiction over the Premises, now in existence and
hereafter enacted and promulgated; and all Insurance Requirements (as defined in
Paragraph T of this Section 1.1.).

                                      -10-
<PAGE>

          T.  "Insurance Requirements" shall mean the requirements and
              ------------------------
recommendations of the insurer carrying the fire and casualty insurance covering
the Building and those of its consultants.

          U.  "Hazardous Materials" shall mean materials, substances, gases,
              ---------------------
chemicals and wastes which are now or in the future defined and regulated under
Laws pertaining thereto as being toxic, radioactive or hazardous or which are
otherwise harmful to health, property or the environment, including, without
limitation,.-.the Laws known as the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended, 49 U.S.C. Para. 9601 et
                                                                         --
seq.; the Hazardous Materials Transportation Act, as amended, 49 U.S.C. Para.
----
1802; the Toxic Substances Control Act, as amended, 15 U.S.C. Para. 2601, et
                                                                          --
seq.; the Massachusetts Oil and Hazardous Material Release Prevention Act, as
----
amended, Massachusetts General Laws Chapter 21E; and the regulations adopted and
publications promulgated pursuant to said Acts.

          V.  "Sublessor's Representatives" shall mean Sublessor's officers,
              -----------------------------
employees, agents, contractors and invitees.

          W.  "Sublessee's Representatives" shall mean Sublessee's officers,
              -----------------------------
employees, agents, contractors and invitees.

          X.  "Sublessor's Consent and Approval" shall be construed to make it
              ----------------------------------
reasonable for Sublessor to withhold its consent or approval in any instance in
which Master Landlord's consent or approval is required under the Master Lease
and such consent or approval is withheld by Master Landlord.

     1.2.  Exhibits and Schedules.  The Exhibits and Schedules listed below in
           ----------------------
this Section are incorporated in this Sublease by reference and are to be
construed as a part of this Sublease:

          SCHEDULE I:  List of Sublessor's Property.
          -----------

                                      -11-
<PAGE>

          EXHIBIT A:   Plan I and Plan 2 showing the Space Layout of each of the
          ----------
                       two levels of the Building.

          EXHIBIT B.1. and 2.:    Premises Delivery Plans.
          --------------------

          EXHIBIT C:   The Master Lease and Exhibits thereto.
          ----------

                                  ARTICLE TWO
                                  -----------
                                Demise-and Term
                                ---------------

     2.1.  Demise.  Sublessor hereby subleases to Sublessee Sublessor's interest
           ------
in the Premises under the Master Lease upon and subject to terms, covenants and
conditions of this Sublease.  Sublessee hereby accepts such Sublease and assumes
all obligations thereunder upon and subject to such terms, covenants and
conditions.  This Sublease is subject to the reserved occupancy rights of
Sublessor as specified in Section 3.1 and is subject to and subordinate to the
Master Lease.

     2.2.  Term.  This Sublease shall be in effect for the duration of the
           ----
Initial Term and shall continue thereafter for the duration of the First
Extended Term if the Term shall have been extended in accordance with Section
2.3 and shall continue-thereafter for the duration of the Second Extended Term
if the Term shall have been extended in accordance with Section 2.4.
Notwithstanding any other provision of this Sublease, the Term shall expire upon
any expiration or termination of the Term of the Master Lease prior to the date
the Term would otherwise have expired pursuant to the provisions of this
Sublease.

     2.3.  First Extended Term.  Subject to the terms and conditions set forth
           -------------------
in Section 2.5, Sublessee shall have the option to extend the Term for the First
Extended Term by giving notice to Sublessor of its election so to extend the
Term on or prior to the date six (6) months prior to the date upon which the
Initial Term expires.

                                      -12-
<PAGE>

     2.4.  Second Extended Term.  Subject to the terms and conditions set forth
           --------------------
in Section 2.5, Sublessee shall have the option to extend the Term for the
Second Extended Term by giving notice to Sublessor of its election so to extend
the Term on or prior to the date six (6) months prior to the date upon which the
First Extended Term expires.

     2.5.  Extension Options, Terms and Conditions.  Time shall be of the
           ---------------------------------------
essence with regard to the exercise by Sublessee of the option to extend the
Term for the First Extended Term and the Second Extended-Term.  It shall be a
condition upon Sublessee's right to exercise either of such extension options
that Sublessee shall not be in default beyond applicable notice and cure periods
in the performance of any material obligations under this Sublease at the time
its notice of election to exercise such option is given or at the commencement
of the First Extended Term or the Second Extended Term, as the case may be.  Any
exercise of either such option by Sublessee later than permitted in Section 2.3
or Section 2.4 or at a time when such a default exists shall be ineffective and
deemed to be null and void.  It shall be a further condition upon Sublessee's
right to extend the Term for the Second Extended Term that Sublessee shall have
properly exercised its option to extend the Term for the First Extended Term.
In the event that Sublessee fails to exercise its option to extend the Term for
the First Extended Term in a valid manner in accordance with this Section and
Section 2.3, then the Term shall expire on the expiration of the Initial Term
with no further rights on the part of Sublessee to extend the Term.  In the
event that the Term is extended for the First-Extended Term in a valid manner
and-that thereafter Sublessee fails to exercise its option to extend the Term
for the Second Extended Term in a valid manner in accordance with this Section
and Section 2.4, the Term shall expire on the expiration of the First Extended
Term with no further rights on the part of Sublessee to extend the Term.  In the
event that the Term is extended for the Second Extended Term in a valid manner,
then the Term shall expire on the expiration of the Second

                                      -13-
<PAGE>

Extended Term with no further rights on the part of Sublessee to extend the
Term. Sublessee shall not have the right to exercise any option granted to
Tenant under the Master Lease to extend the Term of the Master Lease- All of the
terms, covenants and conditions of this Sublease shall apply and govern during
the First Extended Term and the Second Extended Term as fully as during the
Initial Term, except that the Fixed Rent shall be the amounts determined
pursuant to Sections 5.2 and 5.3.

                                 ARTICLE THREE
                                 -------------
                                   Occupancy
                                   ---------

     3.1.  Sublessor's Reserved Occupancy.  Sublessor reserves and have the
           ------------------------------
right to continue to occupy: (a) certain parts of the Premise (as hereinafter
specified) during the months of September and a part of October 1992
(hereinafter referred to as the "Temporary Occupancy Period"); and (b) the
Maverick Production Area until December 31, 1993 or such prior date as Sublessor
shall elect by notice to Sublessee to vacate such Area. Sublessor shall have the
option to continue to occupy the Maverick Production Area for two successive
three-month extension periods as follows:

          (a) the first extension-period shall commence January 1, 1994 and
     terminate March 31, 1994, Sublessor shall give notice to Sublessee that it
     wishes to exercise its option for the first extension period on or before
     September 30, 1993; and

          (b) the second extension period shall commence April 1, 1994 and
     terminate June 30, 1994.  Sublessor shall give Sublessee notice that it
     wishes to exercise its option for the second extension period on or before
     December 31, 1993.

Sublessor shall vacate the Premises (other than the Maverick production Area-)
over the course of the Temporary Occupancy Period so as to deliver possession of
each part of such Premises to Sublessee in phases corresponding to the dates
shown on Exhibit B.1 and 2 attached hereto.  In the

                                      -14-
<PAGE>

event of any delay on the part of Sublessor in the delivery of such possession
by such dates, Sublessor shall have no liability to Sublessee as a result of
such delay, and the terms and conditions of this Sublease shall not be affected
thereby, except that the Rent Commencement Date shall be extended by a period of
time equal to that of such delay if in excess of ten (10) business days, unless
such delay was caused by Sublessee. During the period of time that Sublessor
occupies the Maverick Production Area, Sublessor's Representatives shall have
the right to use the Common Areas in common with Sublessee's Representatives and
the right to use the utility and other Building systems presently serving the
Maverick Production Area subject to payment by Sublessor of the utility charges
provided for in Section 6.1.F.

     3.2.  Sublessee's Initial Occupancy.  Sublessee shall have the right to
           -----------------------------
occupy the Premises during the months of September through and including
December of 1992 for the purpose of carrying out any such alterations,
improvements, installations-and other work as is necessary or desired by
Sublessee in order to prepare the Premises for its use and-occupancy of the
Premises.  Sublessee shall have the right-to occupy the Premises for the purpose
of carrying out and conducting its use of the Premises as permitted by this
Sublease commencing on January 1, 1993 and continuing thereafter for the balance
of the Term.  During the Temporary Occupancy Period, Sublessor shall make
reasonable efforts to enable Sublessee to share the occupancy of the parts of
the Premises it continues to occupy for the purpose of performing such
preparation work to the extent that Sublessee's occupancy and activities shall
not unreasonably interfere with Sublessor's occupancy and Sublessor's activities
in connection with vacating the Premises.  Sublessor shall, during the Temporary
Occupancy Period, cooperate with Sublessee and cause its employees to advise and
consult with Sublessee in connection with the prosecution of such preparation
work by Sublessee's Representatives.

                                      -15-
<PAGE>

                                 ARTICLE FOUR
                                 ------------
                             Condition of Premises
                             ---------------------

     4.1.  Delivery of Premises.  Sublessor shall deliver and Sublessee shall
           --------------------
accept the Premises (including the Maverick Production Area when vacated by
lessor) in "broom clean" condition and otherwise in the same condition as at the
effective date of this Sublease.  All alterations, improvements and other work
necessary or desired by Sublessee for its use and occupancy of the Premises
(hereinafter referred to as "Premises Improvements") shall be carried out by
Sublessee at its expense, subject to reimbursement by Sublessor only to the
extent provided in Section 4.3. Attached hereto as Schedule I is a list of
Sublessor's property which was installed in the Premises by Sublessor at its
expense and which shall remain in the Premises during the Term anal which
Sublessee also accepts in its "as is" condition at the effective date of this
Sublease.

     4.2.  Premises Improvements.  The Premises Improvements shall be carried
           ---------------------
out and performed by Sublessee in accordance with Section 5.1.5 of the Master
Lease and pursuant to plans and specifications approved in advance by Master
Landlord and Sublessor, which approval by Sublessor shall not be unreasonably
withheld or delayed.  In the event that Sublessor shall not, within ten (10)
days after submission to it of such plans and specifications, have given to
Sublessee notice of approval or disapproval, such plans and specifications shall
be deemed to be approved by Sublessor, subject to approval by Master Landlord if
not yet received.  It shall be Sublessee's responsibility at its cost to furnish
such bond or other security as shall be required by Sublessor and the Master
Landlord in connection with the Premises Improvements and in order to guarantee
completion of and full payment for the Premises Improvements by Sublessee.
Sublessee may, at its cost, utilize the existing monument sign in front of the
Building.

                                      -16-
<PAGE>

     4.3.  Reimbursement by Sublessor.  Sublessor shall pay to sublessee towards
           --------------------------
the cost of the Premises Improvements and as sublessor's sole responsibility in
connection therewith the sum of Five Hundred Thousand ($500,000) Dollars,
payable as follows:

          a.  Two Hundred Fifty Thousand ($250,000) Dollars shall be payable on
     the later to occur of April 30, 1993 and the date when the following
     conditions have been satisfied:

               (i) The Premises Improvements shall have been completed pursuant
     to the plans and specifications therefor approved by Sublessor and in full
     compliance with Section 5.1.5 of the Master Lease;

               (ii) Satisfactory proof shall have been given to Sublessor that
     the cost of the Premises Improvements exceeded Five Hundred Thousand
     ($500,000) Dollars and that all vendors and contractors engaged in the
     Premises Improvements shall have been paid in full and shall have provided
     to Sublessee acknowledgments of full payment and waivers of liens;

               (iii)  A Certificate of Occupancy; and

               (iv) No material default shall exist on the part of Sublessee in
     the performance of any of the terms, covenants and conditions of the
     Sublease.

          b.  Provided that the conditions set forth in paragraph a of this
     Section 4.3 were satisfied and the conditions set forth in subparagraph
     (iv) of such paragraph a. is true at the time any further payment is due
     pursuant to this paragraph, the remaining balance of Two Hundred Fifty
     Thousand ($250, 000) Dollars shall be payable in four (4) equal
     installments on April 30 in each of the years 1993, 1994, 1995 and 1996.

                                      -17-
<PAGE>

                                 ARTICLE FIVE
                                 ------------

                                  Fixed Rent
                                  ----------

     5.1.  Initial Term Fixed Rent.  Subject to the rent credits provided for in
           -----------------------
Section Sublessee shall pay Fixed Rent for the Premises beginning on the Rent
Commencement Date and continuing during the balance of the Initial Term at the
rental rate per annum of Six Hundred Ninety Three Thousand ($693,000) Dollars,
payable in equal monthly installments of Fifty Seven Thousand Seven Hundred
Fifty ($57,750) Dollars on the first day of each month beginning with the Rent
Commencement Date.

     5.2.  First Extended Term Fixed Rent.  In the event that the Term shall be
           ------------------------------
extended for the First Extended Term pursuant to Section 2.3, Sublessee shall
pay Fixed Rent for the Premises beginning on the commencement date of the First
Extended Term and continuing during the balance of the First Extended Term at
the rental rate per annum equal to the greater of: (a) Six Hundred Ninety Three
Thousand ($693,000) Dollars; or (b) eighty five (85%) percent of the annual fair
market rental value of the Premises (hereinafter referred to as the "F.M.R.V.")
determined as of the commencement date of the First Extended Term pursuant to
the provisions of Section 5.4; and such Fixed Rent so determined shall be
payable in equal monthly installments on the first day of each month beginning
with the commencement date of the First Extended Term.

     5.3.  Second Extended Term Fixed Rent.  In the event that the Term shall be
           -------------------------------
extended for the Second Extended Term pursuant to Section 2.4, Sublessee shall
pay -Fixed Rent for the Premises beginning on the commencement date of the
Second Extended Term and continuing for the balance of the Second Extended Term
at the rental rate per annum equal to the greater of: (a) the Fixed Rent per
annum payable during the First Extended Term; or (b) ninety five (95%) percent
of the F.M.R.V. determined as of the commencement date of the Second Extended
Term pursuant to the provisions

                                      -18-
<PAGE>

of Section 5.4; and such Fixed Rent so determined shall be payable in equal
monthly installments on the first day of each month beginning with the
commencement date of the Second Extended Term.

     5.4.  Determination of F.M.R.V.  The F.M.R.V. shall be the annual rental
           ------------------------
value as of the date of the commencement of the First Extended Term or as of the
Second Extended Term, whichever date is applicable, of other premises in the
Metro West area of Eastern Massachusetts which are comparable to the Premises in
terms of location, physical condition and legally permitted use, but without
regard to the existing leases of the Premises or to additions or other
improvements to the Premises made by Sublessee at its cost subsequent to the
initial Premises Improvements.  Sublessor shall advise Sublessee, by notice
given to Sublessee within thirty (30) days after the receipt by Sublessor of
Sublessee's notice exercising the option to extend the Term, of the amount it
determines to be the F.M.R.V. of the Premises.  In the event that Sublessee
disagrees with Sublessor's determination of F.M.R.V., it shall give Sublessor
notice to such effect within thirty (30) days after receipt of such notice of
Sublessor's determined F.M.R.V.  In the event Sublessee does not give Sublessor
notice of its disagreement with Sublessor's determination of F.M.R.V. within
such thirty (30) day period, then Sublessor's determination of F.M.R.V. shall be
binding upon Sublessee.  In the event Sublessee does give notice to Sublessor
within such thirty (30) day period of its disagreement with Sublessor's
determination of F.M.R.V., then Sublessee and Sublessor shall each select and
notify the other, within ten (10) days after Sublessor's receipt of such notice
of disagreement, of the name of an M.A.I. appraiser selected by each of them to
prepare 0 and submit to both of them a determination of F.M.R.V. within thirty
(30) days thereafter.  In the event the two appraisers' determination of
F.M.R.V. are within ten (10%) percent of each other, then the F.M.R.V. shall be
deemed to be the average of the two determined amounts.  In the event that such
determined F.M.R.V.'s differ by more than 10%, then the two appraisers shall
promptly select a third appraiser

                                      -19-
<PAGE>

to prepare a determination of F.M.R.V. and the average of the highest two
appraisals of F.M.R.V. shall be deemed to be the F.M.R.V. for the purposes of
this Section. The fees payable to the appraisers shall be shared equally by
Sublessor and Sublessee.

     5.5  Maverick Production Area Fixed Rent Credit.  During the time that
          ------------------------------------------
Sublessor continues to occupy the Maverick Production Area, Sublessee shall
receive a credit as a deduction from the monthly installments of Fixed Rent
equal to:
          (a) The sum of Four Thousand Thirty Three ($4,033) Dollars for each
     month during the Term occurring in 1993 commencing with April that
     Sublessor occupies the Maverick Production Area or a pro rata portion of
     such sum for the part of any such month in which Sublessor discontinues
     such occupancy.

          (b) The sum of Five Thousand Thirty Eight ($5,038) Dollars for each of
     the months January, February and March 1994 that Sublessor occupies the
     Maverick Production Area or a pro rata portion of such sum for the part of
     any such month in which Sublessor discontinues such occupancy;

          (c) The sum of Six Thousand Fifty ($6,050) Dollars for each of the
     months April, May and June 1994 that Sublessor occupies the Maverick
     Production Area or a pro rata portion of such sum for the part of any such
     month in which Sublessor discontinues such occupancy; and

          (d) The sum equal to the entire monthly installment of Fixed Rent for
     each month after June 1994 that Sublessor occupies the Maverick Production
     Area or a pro rata portion of such sum for the part of any such month in
     which Sublessor discontinues such occupancy.

                                      -20-
<PAGE>

     5.6.  Payment of Fixed Rent and Additional Rent.  Fixed Rent and Additional
           -----------------------------------------
Rent shall be payable without any offset or reduction for any reason whatsoever
except as expressly provided for in this Sublease and shall be paid to Sublessor
at the address to which notices are to be sent in accordance with the provisions
of Section 6.1.R.  In the event that any payment of Fixed Rent or Additional
Rent is not received by Sublessor within five (5) days after the due date
therefor, Sublessee shall pay to Sublessor, as Additional Rent payable along
with the payment of such late Fixed Rent or Additional Rent, an amount equal to
interest on such late payment at the rate per annum equal to the lower of:  (a)
two (2%) percent per annum above the so called "prime rate" of interest per
annum charged at that time by the First National Bank of Boston (or any
successor thereto); or (b) the highest interest rate per annum permitted by the
laws of The Commonwealth of Massachusetts.

                                  ARTICLE SIX
                                  -----------
                                 Master Lease
                                 ------------

     6.1.  Incorporation of Master Lease Provisions.  Each of the following
           ----------------------------------------
paragraphs of this Section refer to provisions of the Master Lease which are
either specified as being incorporated into this Sublease, as being omitted from
this Sublease or as being incorporated in part or subject to specific
modifications.  Sublessee shall have no rights or obligations with respect to
those provisions of the Master Lease which are specified below as being omitted
from this Sublease and Sublessor shall have no obligations in favor of Sublessee
pursuant to such omitted provisions.  The provisions of the Master Lease which
are to be incorporated into this Sublease pursuant to such paragraphs of this
Section shall be incorporated herein as fully as if actually set forth in this
Sublease, subject only to those modifications of any such provision as are
specified in the paragraph of this Section applicable thereto, and each
reference in such provisions to `Tenant" shall be deemed to be a

                                      -21-
<PAGE>

reference to Sublessee; each reference in such provisions to "Landlord" shall be
deemed to be a reference to "Sublessor;" and each reference to "Lease" shall be
a reference to this "Sublease."

          A.  The provisions of the First Amendment to Lease dated November 17,
1988 are omitted from this Sublease.

          B.  The provisions of the following Sections of the Master Lease are
incorporated into this Sublease only for Master Lease interpretation purposes:

              Section 1.1.  References.
                            ----------

              Section 1.2.  Exhibits.
                            --------

          C.  The provisions of the following Sections of the Master Lease are
omitted from this Sublease:

              Section 2.1.  Premises.
                            --------

              Section 2.2.  Partial Releases of Parcels from the Premises.
                            ---------------------------------------------

              Section 2.3.  Term.
                            ----

              Section 2.4.  Extended Term.
                            -------------

              Section 3.1.  Acceptance of Premises As Is.
                            ----------------------------

              Section 3.2.  Construction of Addition and Approval of Addition.
                            -------------------------------------------------

              Section 3.3.  Addition Commencement Date.
                            --------------------------

              Section 3.4.  Acceptance of the Premise.
                            -------------------------

              Section 3.5.  Construction Representative.
                            ---------------------------

              Section 3.6.  Landlord's Guarantee of Construction.
                            ------------------------------------

              Section 3.7.  Arbitration.
                            -----------

              Section 4.1.  The Fixed Rent.
                            --------------

              Section 4.2.  Additional Rent.
                            ---------------

                                      -22-
<PAGE>

          D.  The provisions of Section 4.2.1 Real Estate Taxes are incorporated
                                              -----------------
into this Sublease, except that Sublessee's obligation to pay "taxes and
assessments" pursuant to such provisions shall not commence until the Rent
Commencement Date and shall end upon the expiration of the Term, with
appropriate proration for any partial periods to which any such "taxes and
assessments" are attributable and with reimbursement to either of Sublessor or
Sublessee who shall have paid such "taxes and assessments" to be prorated.
Sublessor shall be responsible and shall reimburse Sublessee for "taxes and
assessments" attributable on a pro rata basis to the Maverick Production Area
during the period of time commencing on the Rent Communicant Date and ending on
the date Sublessor discontinues its occupancy of the Maverick Production Area.

          E.  The provisions of Section 4.2.3 Insurance are incorporated into
                                              ---------
this Sublease, except that the all risk insurance required pursuant to Section
4.2.3.1 shall be taken out and maintained by Sublessor rather than Sublessee.
However, Sublessee shall reimburse Sublessor for all premiums paid by Sublessor
for such insurance coverage for the Term, such reimbursement to be made by
Sublessee by payment to Sublessor, as Additional Rent, within ten (10) days
after submission of a statement therefor and a copy of the insurer or agent's
bill for such premium.  However, Sublessee shall have the right to carry such
all risk insurance at its expense by giving written notice of the exercise of
such right to Sublessor at least ten (10) days prior to the effective date of
such insurance coverage.  Upon the giving of such notice, Sublessee shall, on
and subsequent to such effective date, have the obligation to carry and maintain
such insurance pursuant to such Section 4.2.3.1.  All references in such Section
4.2.3 to Landlord shall be deemed references to both Master Landlord and
Sublessor.

          F.  Section 4.2.4 Utilities is incorporated into this Sublease,
                            ---------
except that the charges referred to therein shall be paid by

                                      -23-
<PAGE>

Sublessor prior to April 1, 1993 and shall thereafter be paid by Sublessee for
the balance of the Term. Sublessor shall reimburse Sublessee for such utility
charges attributable to its use of the Maverick Production Area.

          G.  The provisions of Section 4.2.5 Excess Rent are omitted from this
                                              -----------
Sublease.

          H.  The provisions of Section 4.3 Later Payment of Rent are omitted
                                            ---------------------
from this Sublease.

          I.  The provisions of Section 5.1 Affirmative Covenants and 5.1.1
                                            ---------------------
Performance Obligations are incorporated in this Sublease.
-----------------------

          J.  The provisions of Section 5.1.2 Use are incorporated in this
                                              ---
Sublease with the definition of "Permitted Uses" being that set forth in Section
1.1 of the Master Lease.

          K.  The provisions of Section 5.1.3 Repair and Maintenance are
                                              ----------------------
incorporated into this Sublease, except that:

              1)  Sublessor shall be responsible for the performance at its cost
of all repair and maintenance obligations under such Section, up to and
including December 31, 1992, and for all such repair and maintenance obligations
other than "normal repairs and maintenance" from January 1, 1993 up to and
including February 28, 1994, except for those required as a result of the
default, wrongful act, misuse or negligence of Sublessee or its Representatives,
which shall be Sublessee's responsibility at its cost. Except for the repair
obligations of Sublessor defined in subparagraphs 2) and 3) of this paragraph K:
(a) Commencing January 1, 1993, Sublessee shall be responsible for the
performance at its cost of all "normal repairs and maintenance" obligations
under such Section; and (b) Sublessee shall be responsible for the performance
at its cost of all repair and maintenance obligations under such Section for the
balance of the Term commencing March 1, 1994. "Normal repairs and maintenance"
shall be defined to mean those periodic repairs, replacements and maintenance
items that are considered as an incidence of normal use of the Premises and
shall include (without limitation) snow removal from the Common Areas.

                                      -24-
<PAGE>

              2)  Sublessor shall be responsible at its cost for all necessary
repairs to the structural components of the foundations, floor slabs, exterior
walls and roof of the Building and the storm drainage systems, except for those
required as a result of the default, wrongful act, misuse or negligence of
Sublessee or its Representatives, which shall be Sublessee's responsibility at
its cost. Commencing January 1, 1993, Sublessee shall be responsible at its cost
for the periodic inspecting and maintenance of the room in accordance with
generally accepted standards and as required by any bonds or guarantees covering
the roof.

              3)  Commencing January 1, 1993, Sublessee shall be responsible at
its cost for all periodic inspections and maintenance of the heating,
ventilating and air conditioning equipment and systems servicing the Building
(hereinafter referred to as "H.V.A.C."), including all parts and service
required in connection therewith, in accordance with generally accepted
standards and as required by any bonds or guarantees covering the H.V.A.C.
However, in the event that any major component of the H.V.A.C. needs to be
replaced, other than as a result of the default, wrongful act, misuse or
negligence of Sublessee or its Representatives, and such replacement involves a
cost in excess of Five Thousand ($5,000) Dollars and will have a useful life
(determined in accordance with generally accepted accounting principles) in
excess of the balance of the Term at the time of such replacement, then
Sublessor shall be responsible for making such replacement at its cost; however,
if such replacement occurs on or after January 1, 1993, Sublessee shall
thereafter pay to Sublessor, as Additional Rent payable together with the Fixed
Rent, each month during the balance of the Term, the equal monthly installments
of such replacement cost payable for such balance of the Term when amortized
over such useful life on a straight line, constant payment basis, together with
interest (determined as of the commencement of the amortization period) at the
lower of: (a) the rate of two (2%) percent per annum above the so called "prime
rate" of interest per annum charged at that time

                                      -25-
<PAGE>

by the First National Bank of Boston (or any successor thereto); or (b) the
highest rate per annum permitted by the laws of The Commonwealth of
Massachusetts.

              4)  Sublessor's repair and replacement responsibilities under
paragraphs 2) and 3) of this paragraph K shall be subject to and conditional
upon Sublessee giving to Sublessor prompt notice of the need for any such repair
or replacement.

              5)  Notwithstanding anything contained herein to the contrary,
Sublessor shall have no responsibility to maintain or repair any of the Premises
Improvements, or other improvements, additions and alterations made by
Sublessee, which maintenance and repairs shall be the sole responsibility of
Sublessee at its cost.

          L.  The provisions of Section 5.1.4 Compliance with Law and Section
                                              -------------------
5.1.5 Tenant's Work are incorporated into this Sublease.
      -------------

          M.  The provisions of the first paragraph of Section 5.1.6 Indemnity
                                                                     ---------
are incorporated into this Sublease by the provisions of the second paragraph of
such Section are omitted from this Sublease.  Subject to the approval of such
counsel by the Master Landlord, Sublessor shall approve counsel selected by any
insurer which is obligated to defend Sublessor pursuant to such Section 5.1.6
pursuant to any insurance coverage carried by Sublessee.  The term "Landlord"
when used in such Section shall be deemed to refer to both Master Landlord and
Sublessor and, accordingly, the reference to "Indemnified Parties" in such
Section and elsewhere in this Sublease shall include both Master Landlord and
Sublessor, and their respective partners, trustees, stockholders, officers,
directors and employees and beneficiaries of Master Landlord or of any of Master
Landlord's beneficiaries, and holders of mortgages on the Premises and any other
party having an interest in the Premises.  The reference in clause (a) of such
Section 5.1.6 to "Indemnified Parties" shall not include Sublessor's partners,
trustees, stockholders, officers, directors, employees or beneficiaries.

                                      -26-
<PAGE>

          N.  The provisions of the following Sections are incorporated in this
Sublease:

              Section 5.1.7.   Landlord's Right to Enter, with all references
                               -------------------------
     therein to Landlord being deemed a reference to both Master Landlord and
     Sublessor.

              Section 5.1.8.   Personal Property at Tenant's Risk, with all
                               ----------------------------------
     references therein to Landlord being deemed a reference to both Master
     Landlord and Sublessor .

              Section 5.1.10.  Yield Up.
                               --------

              Section 5.1.11.  Estoppel Certificate.
                               --------------------

              Section 5.1.13.  Financial Statements.
                               --------------------

              Section 5.2.     Negative Covenants.
                               ------------------

              Section 5.2.1.   Assignment and Subletting, except that references
                               -------------------------
     to "25%" shall be modified and deemed to be "50%," and the reference to One
     Hundred Million Dollars ($100,000,000) shall be Ten Million Dollars
     ($10,000,000) as it applies to not requiring the consent of Sublessor.
     However, in every instance in which the consent of the Master Landlord is
     required under such Section 5.2.9 with respect to any assignment, transfer,
     mortgage, pledge, granting of a security interest or sublease (as defined
     in such Section), Master Landlord's consent shall be required for any such
     transaction proposed to be carried out by Sublessee.

              Section 5.2.2. Overloading and Nuisance, except that:
                             ------------------------
     (l) references to "hazardous substances" and "toxic substances" shall be
     deemed to refer to all "Hazardous Materials" within the definition of such
     term in this Sublease; (2) Sublessee shall not generate, use, store or
     dispose of, or engage in any activity involving, any Hazardous Materials
     in, on, under or from the Premises, without Sublessor's prior written
     consent which Sublessor may in its sole discretion withhold, whether or not
     reasonable, and to the extent so consented to,

                                      -27-
<PAGE>

     such generation, use, storage or activity shall be carried out only in
     compliance with all Laws applicable thereto; and (3) the second paragraph
     of such section shall be omitted from this Sublease.

              Section 5.2.3. Installation, Alteration or Additions.
                             -------------------------------------

          0.  The provisions of Section 6.1 Termination or Restoration; Rent
                                            --------------------------------
Adjustment, Section 6.2 Eminent Domain, and Section 6.3 Award, of Article VI
----------              --------------                  -----
Casualty or Taking are incorporated into this Sublease, except that references
------------------
to "Landlord" in such Section 6.1 relating to Landlord's obligation to "put the
Premises ... into proper condition for use and occupancy" shall be deemed to be
references solely to Master Landlord so that Sublessor shall have no
responsibility to Sublessee with respect to the performance of such obligation,
except to use reasonable efforts to cause Master Landlord to perform such
obligation; and except that Sublessor expressly reserves the rights of Tenant to
terminate the Master Lease pursuant to Section 6.1 of the Master Lease or such
Section 6.2 of the Master Lease.

          P.  The provisions of ARTICLE VII Defaults are incorporated into this
                                            --------
Sublease.

          Q.  The provisions of ARTICLE VIII Mortgages. are not incorporated
                                             ---------
into this Sublease but this Sublease shall be subject and subordinate to all of
the terms, covenants, conditions and provisions set forth therein.

          R.  The provisions of Section 9.1 Notices from One Party to the Other
                                            -----------------------------------
are incorporated herein, except that the "Original Address of Tenant" shall be
that first above set forth for Sublessee and that the "Original Address of
Landlord" shall be that first above set forth for Sublessor and that all such
notices to Sublessor shall be to the attention of its Vice President General
Counsel and all such notices to Sublessee shall be to the attention of its
Director of Real Estate with a copy (by regular mail) to the Attention of its
General Counsel.

                                      -28-
<PAGE>

          S.  The provisions of the following Sections are incorporated into
this Sublease:

              Section 9.2.  Quiet Enjoyment.
                            ---------------

              Section 9.3.  Lease not to be Recorded.
                            ------------------------

              Section 9.4.  Bind and Inure; Limitation of Landlord's Liability.
                            --------------------------------------------------

              Section 9.5.  Acts of God, except that such provisions shall not
                            -----------
     apply to Section 2.3, 2.4 and 7.2 as to which time shall be of the essence
     or to Sublessee's obligation to pay Fixed Rent or Additional Rent.

              Section 9.6.   Landlord's Default.
                             ------------------

              Section 9.8.   Applicable Law and Construction.
                             -------------------------------

              Section 9.9.   Submission Not an Offer.
                             -----------------------

              Section 9.10.  Limitation of Damages.
                             ---------------------

              Section 9.12.  Rule Against Perpetuities.
                             -------------------------

          T.  The provisions of Section 9.7. Brokerage and Section 9.11.
                                             ---------
Appointment of Tenant Regarding Marlboro Historical Society are not incorporated
-----------------------------------------------------------
into this Sublease and the "List of Materials" attached to the Master Lease is
not applicable to this Sublease.

     6.2.  Compliance with Master Lease.
           ----------------------------

          (a) Sublessee agrees to perform all of its obligations under the
     Master Lease and to otherwise comply with all of the provisions thereof
     incorporated herein for the benefit of both Sublessor and Master Landlord
     and not to engage in or permit any act or omission to occur which would
     result in or cause a default to occur under the Master Lease. Sublessor
     agrees to perform all of its obligations under the Master Lease and to
     otherwise comply with all of the provisions thereof and not to engage in or
     permit any act or omission to occur which would result in or cause a
     default to

                                      -29-
<PAGE>

     occur under the Master Lease. Sublessee and Sublessor each agree to
     indemnify and hold the other harmless from any and all losses, damages and
     costs (including court costs and attorney's fees) incurred as a result of
     any default on their part of their covenants and obligations under this
     Section.

          (b) Without limiting the generality of the indemnity and hold harmless
     provision set forth in paragraph (a) of this Section or the indemnity, hold
     harmless and defend provisions set forth in or incorporated into this
     Sublease, Sublessee shall defend, with counsel approved by Sublessor, which
     approval shall not be unreasonably withheld, indemnify and hold harmless
     the Indemnified Parties from and against all claims, law suits, causes of
     actions, demands, judgments, damages, losses and liabilities, and all
     remedial, testing, investigatory, reporting, legal, consulting and court
     costs and expenses arising as a result of any default by Sublessee of its
     covenants or in the performance of its obligations under Section 5.2.2 of
     the Master Lease as incorporated into this Sublease or otherwise arising
     with respect to or as a result of Sublessee's generation, use, storage or
     disposal of Hazardous Materials in, on, under or from the Premises.
     Sublessee's defend, indemnification and hold harmless obligations under
     this Section shall survive the expiration of the Term.

     6.3.  Master Lease Termination and Surrender.  Sublessor shall have the
           --------------------------------------
right to exercise its options to elect to cancel the Master Lease pursuant to
Article VI thereof, with no liability to Sublessee as a result of such a
termination of the Master Lease.  Sublessor shall also have the right, with no
liability to Sublessee to enter into and carry out at any time an agreement with
the Master Landlord pursuant to which the Master Lease shall be terminated and
surrendered so long

                                      -30-
<PAGE>

as the Master Landlord simultaneously enters into a new direct lease with
Sublessee with the same terms, covenants and conditions as this Sublease, except
for the rights of Sublessee under Section 7.2 (which shall terminate); and
Sublessee hereby agrees to enter into and accept such new direct lease with the
Master Landlord at such time and to agree to and assume the

                                 ARTICLE SEVEN
                                 -------------

                             Development Agreement
                             ---------------------

     7.1.  Development Agreement Rights and Obligations.  The Development
           --------------------------------------------
Agreement is an agreement between Master Landlord and Sublessor which is and
shall be independent and separate from this Sublease.  Accordingly, this
Sublease does not grant any rights to Sublessee or create any obligations upon
Sublessee pursuant to the Development Agreement, and Sublessee shall have no
rights or interests in or with respect to the Unimproved Property, except for
the limited "Right of Prior Negotiation" provided for in Section 7.2.

     7.2.  Right of Prior Negotiation.
           --------------------------

          (a) Subject to the provisions of paragraph (b) of this Section, in the
     event that during the Term Sublessor proposes to purchase or purchases all
     or any part of the Unimproved Property pursuant to the exercise of any
     right or option on the part of Sublessor or Master Lessor under the
     Development Agreement (hereinafter referred to as the "Acquired Property"),
     then Sublessor shall give to Sublessee, prior to offering the Acquired
     Property to third parties (which shall not include Loral Corporation or any
     subsidiary or division thereof), notice that it proposes to or has acquired
     the Acquired Property and a statement of the principal terms and conditions
     upon which Sublessor proposes to offer the Acquired Property for sale or
     lease (hereinafter referred to as the "Offered Terms").  Sublessee shall
     then have the right to elect to purchase or lease the Acquired Property
     upon

                                      -31-
<PAGE>

     the Offered Terms by giving to Sublessor written notice of such election
     (hereinafter referred to as the "Election Notice") on or prior to the date
     which shall be thirty (30) days after the date on which Sublessor shall
     have given its notice of Offered Terms to Sublessee. Time shall be of the
     essence with respect to the date by which Sublessee must give its Election
     Notice. In the event that Sublessee shall give to Sublessor its Election
     Notice within such thirty (30) day period, then Sublessor shall be
     obligated to sell or lease, and Sublessee shall be obligated to purchase or
     lease, the Acquired Property on the Offered Terms, and such transaction
     shall be closed and consummated on a date, at a time and at a location to
     be designated by Sublessor (subject to Sublessee's reasonable approval) by
     written notice given to Sublessee at least thirty (30) days prior to such
     closing date. In the event that Sublessee shall not give its Election
     Notice to Sublessor wit such thirty (30) day period, or in the event that
     Sublessee shall be in default in the performance of any of its obligations
     under this Sublease on the date it gives its Election Notice or on such
     closing date, then, in such cases, Sublessee's rights under this Section
     7.2 shall terminate and shall be of no further force or effect, and
     Sublessor shall have the right to offer, sell or lease the Acquired
     Property free of any option, rights or interests on the part of Sublessee
     pursuant to this Section or otherwise. However, in the event that Sublessor
     does not sell or lease the Acquired Property on terms "substantially" as
     favorable to Sublessor as the Offered Terms and desires to offer, sell or
     lease the Acquired Property at "substantially" less favorable Offered
     Terms, then, in each case in which such Offered Terms are so revised by
     Sublessor, Sublessor shall be obligated to give notice of such offered
     Terms to Sublessee, and Sublessee shall have the right to purchase or lease
     the Acquired Property, pursuant to and in accordance with all of the
     provisions of this Section 7.2. A reduction in the purchase price or fixed
     rent of less than Fifteen (15%) percent shall not be considered
     "substantially" less favorable "Offered Terms."

                                      -32-
<PAGE>

          (b) All of the rights granted to Sublessee pursuant to paragraph (a)
     of this Section 7.2 shall terminate and be of no further force or effect in
     the event that:

               1)  the Development Agreement shall terminate by agreement
          between Sublessor and Sublessee or otherwise; or

               2)  the Master Lease shall terminate or be surrendered by
          agreement between Sublessor and Sublessee or otherwise.


                                 ARTICLE EIGHT
                                 -------------

                         Premises Compliance with Laws
                         -----------------------------

     8.1.  Acceptance Subject to Laws.  The Premises are leased to and accepted
           --------------------------
by Sublessee subject to all Laws. Sublessor, except as provided in Section 8.2,
makes no representations or warranties to Sublessee concerning the Premises
compliance with Laws as of the date hereof other than that, to the best of
Sublessor's knowledge, there are no existing conditions which violate any Laws
which would materially interfere with Sublessee's use of the Premises. Sublessor
makes no representation or warranty to Sublessee regarding the suitability of
the Premises for Sublessee's intended use thereof or regarding the validity of
Sublessee's intended use of the Premises under applicable Laws.

     8.2.  Hazardous Materials Conditions.  Sublessor represents and warrants to
           ------------------------------
Sublessee that, to the best of its knowledge, there are no Hazardous Materials
existing on the date hereof in, on or under the Premises in sufficient quantity
and density to constitute a violation of any Laws applicable to Hazardous
Materials or to require remedial action thereunder, except for the conditions
described in the Request for Proposals prepared by Honeywell Inc., dated
August 19, 1991, entitled

                                      -33-
<PAGE>

"PHASE IV PROGRAM AT FORMER HONEYWELL INC. SITE MARLBORO, MASS." and which
provides for a Remedial Response Implementation Plan and Ground Water
Recovery/Treatment System which Honeywell Inc. is responsible to carry out at
its cost. A copy of such Request for Proposals has been made available to
Sublessee for its review.

                                 ARTICLE NINE
                                 ------------
                                    Brokers
                                    -------

     Sublessor and Sublessee each represent to the other that they have dealt
with no real estate brokers, finders, agents or salesmen in connection with this
transaction other than Spaulding & Slye, George Mintz & Company, Inc., Corporate
Real Estate Advisors and Hunneman Commercial Company (hereinafter referred to as
the "Brokers").  Sublessor agrees to pay the Brokers a fee or commission with
respect to this transaction pursuant to separate written agreements with them.
Each party agrees to indemnify, defend and hold harmless the other party from
and against all claims for brokerage commissions, finders, fees or other
compensation made by any agents, brokers, salesmen or finders other than the
Brokers as a consequence of any actions or dealings of such indemnifying party.

                                  ARTICLE TEN
                                  -----------

                           Master Landlord's Consent
                           -------------------------

     The obligations of both Landlord and Tenant are conditioned upon the
parties hereto receiving the written consent of Master Landlord to this Sublease
as required by Section 5.2.1 of the Master Lease.  Sublessor shall submit this
Sublease to Master Landlord after its execution by Sublessee and Sublessor and
shall request its written consent hereto.  In the event that Master Landlord
shall not provide such written consent within thirty (30) days after such
submission, then,

                                      -34-
<PAGE>

either party may cancel this Sublease by written notice of cancellation given to
the other at any time after the expiration of such thirty (30) day period and
prior to receipt by Sublessor of such consent.

                                      -35-
<PAGE>

     IN WITNESS WHEREOF, Sublessor and Sublessee have executed this Sublease as
of the_____ day September, 1992.

SUBLESSEE:                              SUBLESSOR:

STRATUS COMPUTER, INC.                  LORAL INFRARED & IMAGING SYSTEMS, INC.

By: /s/ Robert E. Donahue               By: /s/ Stephone L. Jackson
    ------------------------                -------------------------
Title: Vice President, CFO              Title: Vice President
       ---------------------                   ----------------------

                                      -36-
<PAGE>

     The undersigned hereby guarantees the performance of the obligations of
Loral Infrared & Imaging Systems, Inc. as Sublessor contained in the within
Sublease.
                                        LORAL CORPORATION

                                        By: /s/ Stephen L. Jackson
                                            ----------------------
                                            Stephen L. Jackson
                                            As Vice President
                                            Administration

                                      -37-