PAUL, WEISS, RIFKIND, WHARTON & GARRISON
                           1285 Avenue of the Americas
                            New York, New York 10019


                                 August 24, 1999


CD Radio Inc.
1221 Avenue of the Americas
New York, New York 10020

                       Registration Statement on Form S-3
                                of CD Radio Inc.
                       ----------------------------------


Ladies and Gentlemen:

                  In connection with the Registration Statement on Form S-3 (the
"Registration Statement") filed by CD Radio Inc., a Delaware corporation (the
"Company"), with the Securities and Exchange Commission (the "Commission")
today, as provided by the Securities Act of 1933, as amended (the "Act"), and
the rules and regulations under the Act, we have been requested to render our
opinion as to the legality of the securities being registered under the
Registration Statement. The Registration Statement relates to the registration
under the Act of (1) the Company's warrants (the "Warrants") to purchase shares
of the Company's common stock, par value $0.001 per







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share (the "Common Stock"), and (2) the shares (the "Warrant Shares") of the
Company's Common Stock issuable upon the conversion of the Warrants.

                  In connection with this opinion, we have examined originals,
conformed copies or photocopies, certified or otherwise identified to our
satisfaction, of the following documents:

                  1. the Registration Statement; and

                  2. the Warrant Agreement (the "Warrant Agreement") between the
         Company and United States Trust Company of New York, as warrant agent
         (the "Warrant Agent").

                  In addition, we have examined: (1) those corporate records of
the Company as we have considered appropriate, including copies of its Amended
and Restated Certificate of Incorporation and Amended and Restated By-laws, as
in effect on the date of this letter, and certified copies of resolutions of the
board of directors of the Company relating to the Warrant Agreement; and (2)
those other certificates, agreements and documents as we deemed relevant and
necessary as a basis for the opinions expressed below.

                  In our examination of the documents referred to above, we have
assumed, without independent investigation, (1) the genuineness of all
signatures, (2) the authenticity of all documents submitted to us as originals,
(3) the conformity to the original documents of all documents submitted to us as
certified, photostatic, reproduced or conformed copies of validly existing
agreements or other documents, (4) the







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authenticity of the latter documents, (5) that the statements regarding matters
of fact in the certificates, records, agreements, instruments and documents that
we examined are accurate and complete and (6) the legal capacity of all
individuals who have executed any of the documents which we examined.

                  In expressing the opinions set forth below, we have relied
upon the factual matters contained in the representations and warranties of the
Company made in the documents and upon certificates of public officials and
officers of the Company.

                  Based on the above, and subject to the stated assumptions,
exceptions and qualifications, we are of the opinion that:

                  1. The Warrant Agreement has been duly authorized, executed
and delivered by the Company and (assuming its due authorization, execution and
delivery by the Warrant Agent) constitutes a valid and binding agreement of the
Company, enforceable against the Company in accordance with its terms.

                  2. The Warrants were duly authorized and validly issued and
are fully paid and nonassessable.

                  3. The Warrant Shares are duly authorized and, when issued,
delivered and paid for in accordance with the Warrant Agreement and as described
in the Registration Statement, the Warrant Shares will be validly issued, fully
paid and nonassessable.

                  Our opinions are subject to the qualification that the
enforceability of the Warrant Agreement may be subject to (a) bankruptcy,
insolvency, fraudulent conveyance







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or transfer, reorganization, moratorium or other similar laws affecting
creditors' rights generally and (b) general principles of equity (regardless of
whether enforcement is considered in a proceeding in equity or at law).

                  Our opinions are limited to the laws of the State of New York,
the federal laws of the United States of America and the General Corporation Law
of the State of Delaware. Our opinions are rendered only with respect to the
laws, and the rules, regulations and orders under those laws, that are currently
in effect. Please be advised that no member of this firm is admitted to practice
in the State of Delaware.

                  We consent to the use of our name in the Registration
Statement and in the prospectus in the Registration Statement as it appears in
the caption "Legal Matters" and to the use of this opinion as an exhibit to the
Registration Statement. In giving this consent, we do not admit that we come
within the category of persons whose consent is required by the Act or by the
rules and regulations under the Act.


                                               Very truly yours,

                                    /s/ Paul, Weiss, Rifkind, Wharton & Garrison

                                      PAUL, WEISS, RIFKIND, WHARTON & GARRISON