SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 10-K

                        FOR ANNUAL AND TRANSITION REPORTS
                     PURSUANT TO SECTIONS 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934


(Mark One)
[X]      ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2006

                                       OR

[  ]     TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE  ACT OF 1934

For the transition period from __________ to __________

                  Commission File Numbers 333-101155, 001-32424


                            MS STRUCTURED ASSET CORP.
                                  On behalf of
                            SATURNS Trust No. 2005-2
             (Exact name of registrant as specified in its charter)


           Delaware                                        13-4026700
--------------------------------------------------------------------------------
(State or other jurisdiction of                (IRS Employer Identification No.)
incorporation or organization)


           1585 Broadway, Second Floor
           New York, New York                               10036
           Attention: Madhu Philips
        (Address of principal executive office)          (Zip Code)

   Registrant's telephone number, including area code:   (212) 761-2520

          Securities registered pursuant to Section 12(b) of the Act:

   Title of Each Class                 Name of Each Exchange on Which Registered

   SATURNS Aon Capital Security         New York Stock Exchange
   Backed Series  2005-2 Class A
   Callable Units

           Securities registered pursuant to Section 12(g) of the Act:

                                      None


<PAGE>


         Indicate  by  check  mark  if  the  registrant is a well-known seasoned
issuer, as defined in Rule 405 of the Securities Act. Yes___ No  X


         Indicate  by  check  mark  if  the  registrant  is not required to file
reports pursuant to Section 13 or 15(d) of the  Securities Exchange Act of 1934.
Yes ___ No    X


         Indicate by  check mark  whether  registrant (1) has filed  all reports
required to be filed by Section 13 or 15(d) of  the  Securities  Exchange Act of
1934  during  the  preceding  12 months  (or for   such  shorter period that the
registrant was required to file such reports), and (2)  has been subject to such
filing requirements for the past 90 days. Yes X No____

         Indicate by check mark if disclosure of  delinquent  filers pursuant to
Item 405 of Regulation S-K is not contained  herein, and will  not be contained,
to the best  of  registrant's  knowledge,  in definitive  proxy  or  information
statements  incorporated  by  reference  in  Part  III of  this Form 10-K or any
amendment to this Form 10-K. [ ]

         Indicate by  check  mark  whether the registrant is a large accelerated
filer,  an  accelerated filer,  or  a non-accelerated  filer. See  definition of
"accelerated  filer  and large  accelerated filer" in Rule 12b-2 of the Exchange
Act. (Check one):

Large accelerated filer ___   Accelerated filer ___   Non-accelerated filer   X


         Indicate  by  check  mark   whether   the   registrant   is   a   shell
company  (as  defined  in  Rule  12b-2  of  the  Act). Yes ___ No     X


         All of the common stock of the registrant is held by Morgan Stanley. As
of March 7, 2007, 1,000 shares of common stock, par value $1.00 per share, were
outstanding.

                      DOCUMENTS INCORPORATED BY REFERENCE:

        The distribution reports to security holders filed on Form 8-K during
the Fiscal Year in lieu of reports on Form 10-Q.

                                Introductory Note

The Registrant is the depositor under the trust agreements for it various
SATURNS Units listed on the New York Stock Exchange. The Units do not represent
obligations of or interests in the Depositor. Pursuant to staff administrative
positions established in various no-action letters, see e.g. Corporate Asset
Backed Corporation (available August 9, 1995), the Registrant is not required to
respond to various items of Form 10-K. Such items are designated herein as "Not
applicable." Distribution reports detailing receipts and distributions by each
trust are filed shortly after each distribution date on Form 8-K in lieu of
reports on Form 10-Q.

The underlying security issuer or guarantor, as applicable, of the securities
held by each of the trusts is subject to the informational requirements of the
Exchange Act. The underlying security issuer or guarantor, as applicable,
currently files reports, proxy statements and other information with the SEC.
For information regarding such underlying security issuer or guarantor, you
should refer to such reports. These periodic, current and other reports and
other information can be inspected and copied at the public reference facilities
maintained by the SEC at Room 1024, 100 F Street, N.E., Washington, D.C. 20549.
Copies of those materials can be obtained by making a written request to the
SEC, Public Reference Section, 100 F Street, N.E., Washington, D.C. 20549, at
prescribed rates. The SEC also maintains a website on the internet at
http://www.sec.gov at which users can view and download copies of reports,
proxy, information statements and other information filed electronically. In
addition, those reports and other information may also be obtained from the
underlying security issuer by making a request to the underlying security
issuer. The trust, the trustee, the Registrant, and their affiliates have not
verified, have not undertaken to verify, and will not verify, the content of any
such reports or information. The name and the central index key (CIK) for each
underlying security issuer or guarantor is set forth below:


     Trust         Underlying Security Issuer or Guarantor               CIK

    2005-2                     Aon Corporation                        0000315293


<PAGE>


                                     PART I

ITEM 1.  BUSINESS

     Not Applicable

ITEM 1A.  RISK FACTORS

     Not Applicable

ITEM 1B.  UNRESOLVED STAFF COMMENTS

     None

ITEM 2.  PROPERTIES

     Not Applicable

ITEM 3.  LEGAL PROCEEDINGS

      None

ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

     None

                                     PART II

ITEM 5.  MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS

The Units issued by the SATURNS trusts listed below representing investors'
interest in such trust are represented by one or more physical certificates
registered in the name of Cede & Co., the nominee of The Depository Trust
Company. The Units are listed on the New York Stock Exchange:

SATURNS Trust No. 2005-2 Class A Units (Aon Capital Security Backed )

ITEM 6.  SELECTED FINANCIAL DATA

     Not Applicable

ITEM 7.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
         OF OPERATIONS

     Not Applicable


<PAGE>


ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

     Not Applicable

ITEM 8.  FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

     Not Applicable

ITEM 9.  CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
         FINANCIAL DISCLOSURE

     None

ITEM 9A. CONTROLS AND PROCEDURES

     Not Applicable

ITEM 9B.  OTHER INFORMATION

     None

                                    PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

     None

ITEM 11. EXECUTIVE COMPENSATION

     Not Applicable

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

     None

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

     None

ITEM 14. PRINCIPAL ACCOUNTING FEES AND SERVICES

     Not Applicable


<PAGE>


                                     PART IV

ITEM 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K

         (a) The following documents are filed as part of this Report: None

         (b) Reports on Form 8-K:

See Table Below:

<TABLE>
<CAPTION>
 SATURNS Trust No.:        Closing Date              Payment Dates              Form 8-K Filing Dates (Not Trust
                                                                              Agreement Filings in connection with
                                                                                          Closing Date)

                                                                                           For FY 2006
<S>                       <C>                   <C>                           <C>
2005-2                    1/27/05               January 1 and July 1           January 9, 2006 and July 11, 2006
</TABLE>

         (c) Exhibits:

Exhibit 23        Consent of Pustorino, Puglisi & Co., LLP (See Exhibit 99.1--
                  contained in final paragraph of accountants' letter)
Exhibit 31.1      Rule 13a-14(d) Certification
Exhibit 31.2      Trustee Compliance Certification
Exhibit 99.1      Report of Pustorino, Puglisi & Co., LLP

         (d) Not applicable


<PAGE>


                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.



         Date:  March 28, 2007

                                                       MS STRUCTURED ASSET CORP.
                                                       (Registrant)



                                                  By:      /s/Madhu Philips
                                                     ---------------------------
                                                  Name:    Madhu Philips
                                                  Title:   Vice President


<PAGE>


                                                                      Exhibit 23
                   [Consent of Pustorino, Puglisi & Co., LLP]


<PAGE>


                                                                    Exhibit 31.1

                          Rule 13a-14(d) Certification

I, Madhu Philips, certify that:

1. I have reviewed this annual report on Form 10-K, and all reports on Form 8-K
containing distribution or servicing reports filed in respect of periods
included in the year covered by this annual report, of MS Structured Asset Corp.
on behalf of SATURNS Trust No. 2005-2;

2. Based on my knowledge, the information in these reports, taken as a whole,
does not contain any untrue statement of a material fact or omit to state a
material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading as of the
last day of the period covered by this annual report;

3. Based on my knowledge, the distribution or servicing information required to
be provided to the depositor by the trustee under the pooling and servicing, or
similar, agreement, for inclusion in these reports is included in these reports;

4. I am responsible for reviewing the activities performed by the depositor and
the trustee under the pooling and servicing, or similar, agreement and based
upon my knowledge and the annual compliance review required under that
agreement, and except as disclosed in the reports, the depositor and trustee
have each fulfilled its obligations under that agreement; and

5. The reports disclose all significant deficiencies relating to the compliance
by the trustee and the depositor with the minimum servicing or similar standards
based upon the report provided by an independent public accountant, after
conducting a review in compliance with the Uniform Single Attestation Program
for Mortgage Bankers or similar procedure, as set forth in the pooling and
servicing, or similar, agreement, that is included in these reports.

In giving the certifications above, I have reasonably relied on information
provided to me by the following unaffiliated parties: LaSalle Bank National
Association and its officers and agents.



                                                  By:      /s/Madhu Philips
                                                     ---------------------------
                                                  Name:    Madhu Philips
                                                  Title:   Vice President
                                                  Date:    March 28, 2007


<PAGE>


                                                                    Exhibit 31.2

                             COMPLIANCE CERTIFICATE

                  In connection with the preparation and delivery of the annual
report on Form 10-K of MS Structured Asset Corp. on behalf of SATURNS Trust No.
2005-2 for the fiscal year ending December 31, 2006, and the certifications
given by Madhu Philips with respect thereto, the undersigned hereby certifies
that she is a duly elected Vice President of LaSalle Bank National Association
and further certifies in her capacity as such as follows:


1. LaSalle Bank National Association has prepared all distribution reports with
respect to each distribution date for SATURNS Trust No. 2005-2, and has filed a
copy of such reports on Form 8-K during the fiscal year as described on Exhibit
A hereto.

2. I have reviewed all reports on Form 8-K containing distribution reports filed
in respect of periods included in the fiscal year covered by the annual report
of MS Structured Asset Corp. on behalf of SATURNS Trust No. 2005-2;

3. I am familiar with the operations of LaSalle Bank National Association with
respect to the SATURNS program and SATURNS Trust No. 2005-2 and the requirement
imposed by the applicable trust agreement;

4. Based on my knowledge, the information in the distribution reports, taken as
a whole, does not contain any untrue statement of a material fact or omit to
state a material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading as of the
last day of the period covered by the annual report;

5. Based on my knowledge, the information required to be provided under each
trust agreement, for inclusion in these reports, is included in these reports;

6. Based on my knowledge, and except as disclosed in the reports, the trustee
has fulfilled its obligations, including any servicing obligations, under the
trust agreement.

7. Based on my knowledge, and except as disclosed in the reports, there are no
material legal proceedings with respect to any trust, involving the trust or
LaSalle Bank National Association as trustee.


                                            By:      /s/Barbara L. Marik
                                               ---------------------------------
                                            Name:    Barbara L. Marik
                                            Title:   First Vice President
                                            Date:    March 27, 2007


<PAGE>


                                                                       EXHIBIT A

<TABLE>
<CAPTION>
SATURNS Trust No.:      Closing Date             Payment Dates            Form 8-K Filing Dates (Not Trust Agreement
                                                                            Filings in connection with Closing Date)

                                                                                        For FY 2006
<S>                      <C>                    <C>                        <C>
2005-2                   1/27/05               January 1 and July 1         January 9, 2006 and July 11, 2006
</TABLE>


<PAGE>


                                                                    Exhibit 99.1

                    [Report of Pustorino, Puglisi & Co., LLP]


<PAGE>


                  [On Pustorino, Puglisi & Co., LLP Letterhead]



                         INDEPENDENT ACCOUNTANT'S REPORT
                       ON APPLYING AGREED-UPON PROCEDURES



LaSalle Bank National Association
135 S. LaSalle Street, Suite 1625
Chicago, IL 60603

MS Structured Asset Corp.
1585 Broadway
New York, NY 10036


With respect to the "Structured Asset Trust Unit Repackagings 2005-2" (SATURNS
Trust 2005-2) we have performed the procedures listed below, which were agreed
to by LaSalle Bank National Association (the Trustee) and MS Structured Asset
Corp. (the Depositor) solely to assist the Depositor in evaluating the Trustee's
assertions that the administration of the Trust Property of SATURNS Trust 2005-2
(the Trust) was conducted in accordance with the terms of the Trust Agreement
relating thereto for the year ended December 31, 2006. This agreed-upon
procedures engagement was performed in accordance with attestation standards
established by the American Institute of Certified Public Accountants. The
sufficiency of these procedures is solely the responsibility of the specified
users of this report, the Trustee and the Depositor. Consequently, we make no
representation regarding the sufficiency of the procedures described below
either for the purpose for which this report has been requested or for any other
purpose.

Pursuant to the foregoing, for SATURNS TRUST 2005-2, we:

     1.   Calculated the semi-annual interest payment on the underlying security
          as defined in the prospectus.

     2.   Verified  that  interest  payments  on the  underlying  security  were
          received on the scheduled date for payment thereof.

     3.   Calculated  the  semi-annual  interest   distributions  and  principal
          distributions, if any, on the Class A and Class B units.


<PAGE>


                                      -2-

     4.   Verified that  distributions on Class A and Class B units were made on
          the scheduled dates for distribution thereof.

     5.   Verified Trust property amounts and balances.

     6.   Verified  that the  amounts  of any units  redeemed,  upon  receipt of
          redemption  payments  or  notices of  exercise  of  warrants,  matched
          amounts of the  relevant  redemptions  and  warrant  exercise  amounts
          notified to the Trustee.

     7.   Verified  that the proceeds of  redemptions,  exercise of warrants and
          liquidation of underlying securities following any underlying security
          default were applied within the time and in the manner provided in the
          Trust Agreement.

     8.   Verified  that  reports on Form 8-K were filed by the Trustee with the
          Securities  and Exchange  Commission  on or before the  fifteenth  day
          following each payment date for the Class A and Class B units.

We were not engaged to, and did not, perform an examination, the objective of
which would be the expression of an opinion on the Trustee's assertions.
Accordingly, we do not express such an opinion. Had we performed additional
procedures, other matters might have come to our attention that would have been
reported to you.

We are independent public accountants with respect to the Trustee and the Trust,
as defined under the Code of Professional Ethics of the American Institute of
Certified Public Accountants.

This report is intended solely for the use of the Depositor and the Trustee and
should not be used by those who have not agreed to the procedures and taken
responsibility for the sufficiency of the procedures for their purposes.
However, this report is a matter of public record as a result of being included
as an exhibit to the annual report on Form 10-K prepared by MS Structured Asset
Corp. and filed with the Securities and Exchange Commission on behalf of SATURNS
Trust 2005-2, and its distribution is not limited.


/s/ Pustorino, Puglisi & Co., LLP
---------------------------------

Pustorino, Puglisi & Co., LLP
New York, New York
March 7, 2007


<PAGE>


                   [On MS Structured Asset Corp. Letterhead]






March 28, 2007



Pustorino, Puglisi & Co., LLP
515 Madison Avenue
New York, NY 10022

Gentlemen:

In connection with your engagement to apply the agreed-upon procedures, as
listed in your engagement letters dated January 29, 2007 and your reports dated
March 7, 2007, for the Trusts listed below:

           SATURNS 2003-11                                     SATURNS 2004-2
           SATURNS 2003-12                                     SATURNS 2004-4
           SATURNS 2003-13                                     SATURNS 2004-6
           SATURNS 2003-15                                     SATURNS 2005-1
           SATURNS 2003-16                                     SATURNS 2005-2
           SATURNS CBT Series 2003-1                           SATURNS 2005-3
           SATURNS 2004-1


We confirm, to the best of our knowledge and belief, the following
representations made to you during your engagement:

     1.   We are  responsible  for the  formulation  of the  assertion  that the
          administration  of the Trusts listed above was conducted in accordance
          with the terms of the individual Trust Agreements relating thereto for
          the year ended December 31, 2006.

     2.   There have been no  fraudulent or other illegal acts that would have a
          material effect on the assertion.

     3.   We  have  disclosed  to  you  all  known  matters   contradicting  the
          assertion.


<PAGE>


                                       -2-

     4.   There have been no  communications  from  internal  auditors and other
          independent  practitioners  or consultants  relating to the assertions
          including  communications  received  between December 31, 2006 and the
          date of this letter.

     5.   We have made  available  to you all  information  that we  believe  is
          relevant to the assertion.

     6.   We have responded  fully to all inquiries made to us by you during the
          engagement.

     7.   No events have  occurred  subsequent  to December  31, 2006 that would
          require adjustment to or modification of the assertions.

     8.   Your report is intended  solely for the use of LaSalle  Bank  National
          Association   (the  Trustee)  and  MS  Structured   Asset  Corp.  (the
          Depositor)  and should not be used by those who have not agreed to the
          procedures  and  taken  responsibility  for  the  sufficiency  of  the
          procedures for their purposes. We intend for the applicable reports to
          be a matter of public record as a result of their being included as an
          exhibit to the annual  report on Form 10-K  prepared by MS  Structured
          Assets Corp. and filed with the Securities and Exchange  Commission on
          behalf of the corresponding trusts.



   /s/Madhu Philips
-----------------------------
Signature


  Authorized Signatory
-----------------------------
Title


  March 28, 2007
-----------------------------
Date


<PAGE>


               [On LaSalle Bank National Association Letterhead]







March 7, 2007



Pustorino, Puglisi & Co., LLP
515 Madison Avenue
New York, NY 10022

Gentlemen:

In connection with your engagement to apply the agreed-upon procedures, as
listed in your engagement letters dated January 29, 2007 and your reports dated
March 7, 2007, for the Trusts listed below:

           SATURNS 2003-11                                     SATURNS 2004-2
           SATURNS 2003-12                                     SATURNS 2004-4
           SATURNS 2003-13                                     SATURNS 2004-6
           SATURNS 2003-15                                     SATURNS 2005-1
           SATURNS 2003-16                                     SATURNS 2005-2
           SATURNS CBT Series 2003-1                           SATURNS 2005-3
           SATURNS 2004-1


We confirm, to the best of our knowledge and belief, the following
representations made to you during your engagement:

     1.   We are  responsible  for the  formulation  of the  assertion  that the
          administration  of the Trusts listed above was conducted in accordance
          with the terms of the individual Trust Agreements relating thereto for
          the year ended December 31, 2006.

     2.   There have been no  fraudulent or other illegal acts that would have a
          material effect on the assertion.

     3.   We  have  disclosed  to  you  all  known  matters   contradicting  the
          assertion.


<PAGE>


                                       -2-

     4.   There have been no  communications  from  internal  auditors and other
          independent  practitioners  or consultants  relating to the assertions
          including  communications  received  between December 31, 2006 and the
          date of this letter.

     5.   We have made  available  to you all  information  that we  believe  is
          relevant to the assertion.

     6.   We have responded  fully to all inquiries made to us by you during the
          engagement.

     7.   No events have  occurred  subsequent  to December  31, 2006 that would
          require adjustment to or modification of the assertions.

     8.   Your report is intended  solely for the use of LaSalle  Bank  National
          Association   (the  Trustee)  and  MS  Structured   Asset  Corp.  (the
          Depositor)  and should not be used by those who have not agreed to the
          procedures  and  taken  responsibility  for  the  sufficiency  of  the
          procedures for their purposes. We intend for the applicable reports to
          be a matter of public record as a result of their being included as an
          exhibit to the annual  report on Form 10-K  prepared by MS  Structured
          Assets Corp. and filed with the Securities and Exchange  Commission on
          behalf of the corresponding trusts.



   /s/Andy Streepey
------------------------------
Signature


 Assistant Vice President
---------------------------
Title


  March 9, 2007
---------------------------
Date