EXHIBIT 4.4.6

                                                                  EXECUTION COPY

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                    COLLATERAL PLEDGE AND SECURITY AGREEMENT

                                     Between

                                  CD RADIO INC.
                                   as Pledgor

                                       and

                     UNITED STATES TRUST COMPANY OF NEW YORK
                                   as Trustee










                            Dated as of May 15, 1999






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                             COLLATERAL PLEDGE AND SECURITY AGREEMENT, dated as
                      of May 15, 1999, between CD RADIO INC., a Delaware
                      corporation ("CD Radio" and the "Pledgor"), and UNITED
                      STATES TRUST COMPANY OF NEW YORK, as trustee (the
                      "Trustee"), for the holders of the Notes (as defined
                      herein). Capitalized terms used but not otherwise defined
                      herein shall have the meanings given to such terms in the
                      Indenture (as defined herein).

               The Pledgor and the Trustee have entered into that certain
Indenture, dated as of May 15, 1999 (as amended, restated, supplemented or
otherwise modified from time to time, the "Indenture"), pursuant to which the
Pledgor is issuing $200,000,000 aggregate principal amount of its 14-1/2% Senior
Secured Notes due 2009 (the "Notes").

               The Pledgor has agreed, pursuant to the Indenture, to (i)
purchase a portfolio of U.S. Government Obligations (the "Pledged Securities")
with scheduled principal and interest payments that will result in the receipt
of United States dollars in an amount and at a time sufficient, based on the
schedule of interest and principal payments in respect of such Pledged
Securities (with reinvestment) (as calculated and set forth in a written
certificate furnished to the Trustee of an internationally recognized firm of
independent certified public accountants selected by the Pledgor), to provide
for payment in full of the six regularly scheduled interest payments due on the
Notes from November 15, 1999 through May 15, 2002 (the "Secured Payments") and
(ii) place the Pledged Securities in the Pledge Account (as defined herein) held
by the Trustee for the benefit of the holders of the Notes.

               The Pledgor is to be the sole legal and beneficial owner of the
Pledged Securities; and

               To secure the payment and performance by the Pledgor of its
obligations under the Indenture and the Notes (collectively, the "Obligations"),
the Pledgor has agreed to pledge to the Trustee for the ratable benefit of the
holders of the Notes a security interest in the Pledged Securities and the
Pledge Account and execute and deliver this Agreement.










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               The parties hereto hereby agree as follows:

               1. Pledge and Grant of Security Interest. The Pledgor hereby
pledges to the Trustee for the ratable benefit of the holders of the Notes, and
grants to the Trustee for the ratable benefit of the holders of the Notes, a
continuing first priority security interest in and to (i) all of the Pledgor's
right, title and interest in the Pledged Securities and the Pledge Account, (ii)
all certificates or other evidence of ownership representing the Pledged
Securities and the Pledge Account and (iii) all products and proceeds of any of
the Pledged Securities, including all dividends, interest payments, principal
payments, cash, options, warrants, rights, instruments, subscriptions and other
property or proceeds from time to time received, receivable or otherwise
distributed or distributable in respect of or in exchange for any or all of the
Pledged Securities (collectively, the "Collateral").

               2. Security for Obligations. This Agreement and the Collateral
secure the prompt and complete payment and performance when due (whether at
stated maturity, by acceleration or otherwise) of all of the Obligations.

               3. Delivery of Collateral; Pledge Account; Interest. (a) All
certificates or instruments representing or evidencing the Pledged Securities
shall be delivered to and held by or on behalf of the Trustee pursuant hereto
and shall be in suitable form for transfer and delivery, or shall be accompanied
by instruments of transfer or assignment duly executed in blank all in form
satisfactory to the Trustee, or shall be delivered to the Trustee through the
book-entry facilities of the applicable depositary.

               (b) Concurrently with the execution and delivery of this
Agreement, the Trustee shall establish an account entitled the "CD RADIO PLEDGE
ACCOUNT" for the deposit of the Pledged Securities (the "Pledge Account").
Subject to the other terms and conditions of this Agreement, all funds or other
property accepted by the Trustee pursuant to this Agreement shall be held in the
Pledge Account for the ratable benefit of the holders of the Notes. The Pledged
Securities shall be registered in the name of the Trustee or its nominee, as
Trustee for the benefit of the holders of the Notes, and the proceeds of any
such Pledged Securities shall remain on deposit in the Pledge Account until
withdrawn in accordance with this Agreement. If and to the extent the Pledged
Securities comprise certificated securities (as defined in Section 8-102 of the
Uniform Commercial Code in the State of New York), such Pledged Securities shall
be registered in the name of the Trustee or










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its nominee, as Trustee for the benefit of the holders of the Notes, and
possession thereof shall be maintained by the Trustee within the State of New
York.

               (c) All interest earned on or other distributions or amounts paid
with respect to any Collateral shall be retained in the Pledge Account and may
be reinvested by and at the direction of the Pledgor in other U.S. Government
Obligations and treated as Pledged Securities; provided, however, that the
Pledgor may only so reinvest such interest, distributions or amounts if, based
on a written report of an internationally recognized firm of independent public
accountants selected by the Pledgor and addressed to the Trustee, scheduled
principal and interest payments on the Pledged Securities retained in the Pledge
Account (after giving effect to such reinvestment) will result in receipt of
United States dollars in an amount and at a time sufficient, without further
reinvestment, to provide for payment in full when due of each of the Secured
Payments (or, in the event any such Secured Payments have been made, the
remaining unpaid Secured Payments).

               4. Disbursements. (a) Not less than one Business Day prior to the
date of each of the Secured Payments, the Pledgor is entitled to direct the
Trustee in writing to transfer from the Pledge Account to the Trustee in its
capacity as Paying Agent (or, if applicable, any successor Paying Agent), United
States dollars in immediately available funds necessary to provide for payment
in full of or any portion of the next regularly scheduled interest payment on
the Notes. Upon receipt of such written request, the Trustee shall take such
action as is necessary to provide for the timely payment of such amount of
United States dollars in immediately available funds directly to the Trustee as
Paying Agent (or, if applicable, any successor Paying Agent) from proceeds of
the Pledged Securities held in the Pledge Account.

               (b) If the Pledgor elects to pay any Secured Payment (or any
portion thereof) from a source of funds other than the Pledge Account (the
"Pledgor's Funds"), then the Pledgor may on at least two Business Days' prior
written notice, after payment in full in cash of such Secured Payment (evidenced
by an Officers' Certificate delivered to the Trustee stating that such regularly
scheduled interest payment has been made in accordance with the terms of the
Indenture), direct the Trustee in writing to release to the Pledgor (or as it
may direct) an amount of funds or Pledged Securities, at the Pledgor's sole
option, from the Pledge Account not to exceed the amount of Pledgor's Funds so
expended, without accounting for any Pledgor's Funds so










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expended in payment of Defaulted Interest. Upon receipt of such written
direction from the Pledgor, together with (i) the certificate described in the
preceding sentence and (ii) the written report of an internationally recognized
firm of independent certified public accountants selected by the Pledgor and
addressed to the Trustee certifying that the scheduled payments of principal of
and interest on the Pledged Securities exceeds 100% of the amount in cash
sufficient to provide for timely payment in full of the Secured Payments (or, in
the event any Secured Payments have been made, an amount in cash sufficient to
provide for timely payment in full of the remaining unpaid Secured Payments),
the Trustee shall take such action as is necessary to provide for the prompt
payment to the Pledgor of the amount of funds or Pledged Securities requested
from the Pledge Account.

               (c) If at any time the scheduled payments of principal of and
interest on the Pledged Securities exceeds 100% of the amount in cash
sufficient, based on a written report of an internationally recognized firm of
independent certified public accountants selected by the Pledgor and addressed
to the Trustee, to provide for timely payment in full of the Secured Payments
(or, in the event any Secured Payments have been made, an amount in cash
sufficient to provide for timely payment in full of the remaining unpaid Secured
Payments), the Pledgor may direct the Trustee in writing to release to the
Pledgor (or as it may direct) an amount of funds or Pledged Securities, at the
Pledgor's sole option, not to exceed such excess. Upon receipt of such written
direction from the Pledgor, together with such report of such internationally
recognized firm of independent certified public accountants, the Trustee shall
take such action as is necessary to provide for the prompt payment to the
Pledgor of the amount of funds or Pledged Securities equal to such excess, as
identified in such report.

               (d) Upon payment in full of the Secured Payments, evidenced by an
Officers' Certificate delivered to the Trustee stating that such regularly
scheduled interest payments have been made in full in accordance with the
Indenture, then so long as no Default or Event of Default shall have occurred
and be continuing, (i) the security interest in the Collateral evidenced by this
Agreement shall terminate and be of no further force and effect and (ii) any
funds remaining in the Pledge Account will be promptly returned to the Pledgor.
Furthermore, upon release of any Collateral from the Pledge Account in
accordance with the terms of this Agreement, the security interest evidenced by










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this Agreement in the Collateral so released shall terminate and be of no
further force and effect.

               5. Representations and Warranties. The Pledgor hereby represents
and warrants that:

               (a) the execution, delivery and performance by the Pledgor of
        this Agreement has been duly authorized by the Pledgor and does not
        contravene or constitute a default under any provision of applicable law
        or regulation to which the Pledgor is subject, the certificate of
        incorporation or the by-laws, as the case may be, of the Pledgor, or of
        any judgment, injunction, order, decree or any material agreement or
        instrument binding upon the Pledgor, and does not result in the creation
        or imposition of any Lien on any asset of the Pledgor, except for the
        security interests granted under this Agreement;

               (b) no financing statement covering the Pledged Securities is on
        file in any public office, other than financing statements filed
        pursuant to this Agreement;

               (c) upon the delivery to the Trustee of the certificates, if any,
        representing the Pledged Securities, any filing of financing statements
        required by the Uniform Commercial Code (the "UCC") and notation on the
        records of the Trustee that it holds the Pledged Securities as pledgee,
        the pledge of the Collateral pursuant to this Agreement will constitute
        a valid and perfected first priority security interest in and to the
        Collateral, securing the payment and performance of the Obligations for
        the ratable benefit of the holders of the Notes, enforceable as such
        against all creditors of the Pledgor and any persons purporting to
        purchase any of the Collateral from the Pledgor;

               (d) no consent of any other person and no consent, authorization,
        approval, or other action by, and no notice to or filing with, any
        governmental authority or regulatory body in the United States or
        otherwise, including any taxing authority, is required to be obtained or
        made by the Pledgor as of the date hereof either (i) for the pledge by
        the Pledgor of the Collateral pursuant to this Agreement or for the
        execution, delivery or performance of this Agreement by the Pledgor
        (except for any filings and notations necessary to perfect the security
        interest created hereby in the Collateral) or (ii) for the exercise by
        the Trustee of the rights provided for in this Agreement or the remedies
        in respect of the Collateral










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        pursuant to this Agreement (except as may be required by laws affecting
        the offering and sale of securities generally); and

               (e) the pledge of the Collateral pursuant to this Agreement is
        not prohibited by any applicable law or government regulation, release,
        interpretation or opinion of the Board of Governors of the Federal
        Reserve System or other regulatory agency in the United States or
        otherwise (including any taxing authority or Regulations T, U and X of
        the Board of Governors of the Federal Reserve System).

               6. Further Assurances. The Pledgor agrees to promptly take such
actions and to execute and deliver or cause to be executed and delivered, or use
its best efforts to procure, such stock or bond powers, proxies, assignments,
instruments and such other or different writings as the Trustee may reasonably
request, all in form and substance satisfactory to the Trustee, deliver any
instruments to the Trustee and take any other actions that are necessary or, in
the opinion of the Trustee, desirable, to perfect, continue the perfection of,
confirm and assure the first priority of the Trustee's security interest in the
Collateral, to protect the Collateral against the rights, claims or interests of
third persons, or to otherwise effect the purposes of this Agreement.
Notwithstanding the foregoing, the Trustee shall have no duty or obligation to
ensure the maintenance or perfection of any security interest hereunder.

               7. Covenants. The Pledgor covenants and agrees with the Trustee
and the holders of the Notes from and after the date of this Agreement until the
earlier of payment in full of cash in United States dollars of (A) each of the
Secured Payments under the terms of the Indenture and (B) all Obligations due
and owing under the Indenture and the Notes in the event such Obligations become
due and payable prior to the payment in full of any of the Secured Payments, as
follows:

               (a) The Pledgor agrees that it (i) will not sell or otherwise
dispose of, or grant any option or other interest with respect to, any of the
Collateral, (ii) will not create or permit to exist any Lien upon or with
respect to any of the Collateral, except for the Liens created pursuant to this
Agreement and (iii) will at all times be the sole beneficial owner of the
Collateral.

               (b) The Pledgor agrees that it will not (i) enter into any
agreement or understanding that purports to or may










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restrict or inhibit the Trustee's rights or remedies hereunder, including the
Trustee's right to sell or otherwise dispose of the Collateral, or (ii) with
regard to the Collateral, fail to pay or discharge any tax, assessment or levy
of any nature due with respect thereto later than five days prior to the date of
any proposed sale under any judgment, writ or warrant of attachment.

               8. Power of Attorney. (a) The Pledgor hereby appoints and
constitutes the Trustee as the Pledgor's attorney-in-fact to exercise to the
fullest extent permitted by law all of the following powers upon and at any time
after the occurrence and during the continuance of an Event of Default:

               (i) collection of proceeds of any Collateral;

               (ii) conveyance of any item of Collateral to any purchaser
        thereof as specified herein;

               (iii) giving of any notices or recording of any Liens pursuant to
        Section 6 hereof;

               (iv) making any payments or taking any acts pursuant to Section 9
        hereof; and

               (v) paying or discharging taxes or Liens levied or placed upon
        the Collateral, the legality or validity thereof and the amounts
        necessary to discharge the same to be determined by the Trustee in its
        sole and reasonable discretion, and any such payments made by the
        Trustee shall become Obligations of the Pledgor to the Trustee, due and
        payable immediately upon demand.

               (b) The Trustee's authority under this Section 8 shall include
the authority to endorse and negotiate any checks or instruments representing
proceeds of Collateral in the name of the Pledgor, execute and give receipt for
any certificate of ownership or any document constituting Collateral, transfer
title to any item of Collateral, to the extent permitted by applicable law, sign
the Pledgor's name on all financing statements or any other documents deemed
necessary or appropriate by the Trustee to preserve, process or perfect the
security interest in the Collateral, and to file the same, and to prepare, sign
the Pledgor's name and file any notice of Lien, and to take any other actions
arising from or incident to the powers granted to the Trustee in this Agreement.
This power of attorney is coupled with an interest and shall be irrevocable by
the Pledgor.










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               9. Trustee May Perform. If the Pledgor fails to perform any
agreement contained herein, the Trustee may, but shall not be obligated to,
itself perform or cause performance of such agreement, and the reasonable
expenses incurred by or on behalf of the Trustee in connection therewith shall
be payable by the Pledgor under Section 13 hereof.

               10. No Assumption of Duties; Reasonable Cure. The rights and
powers granted to the Trustee hereunder are being granted in order to preserve
and protect the security interest of the holders of Notes in and to the
Collateral granted hereby and shall not be interpreted to, and shall not, impose
any duties on the Trustee in connection therewith other than those imposed under
applicable law.

               11. Indemnity. The Pledgor shall indemnify, defend and hold
harmless the Trustee and its directors, officers, agents and employees from and
against all claims, actions, obligations, losses, liabilities and expenses,
including costs, fees and disbursements of counsel, the costs of investigations,
and claims for damages, arising from the Trustee's performance under this
Agreement, except insofar as the same may have been caused by such indemnified
person's own negligent action, its own negligent failure to act or its own
willful misconduct. The obligations of the Pledgor under this Section 11 shall
survive the resignation or removal of the Trustee and the termination of this
Agreement.

               12. Remedies upon Event of Default. If an Event of Default shall
have occurred:

               (a) The Trustee shall have and may exercise with reference to the
Collateral any or all of the rights and remedies of a secured party under the
UCC in effect in the State of New York, and as otherwise granted herein or under
any other applicable law or under any other agreement now or hereafter in effect
executed by the Pledgor, including the right and power to sell, at public or
private sale or sales, or otherwise dispose of, or otherwise utilize the
Collateral and any part or parts thereof, in any manner authorized or permitted
under said UCC after default by a debtor, and to apply the proceeds thereof
toward payment of any costs and expenses and attorneys' fees and expenses
thereby incurred by the Trustee and toward payment of the Obligations in
accordance with Section 12(c). Specifically, and without limiting the foregoing,
the Trustee shall have the right to take possession of all or any part of the
Collateral or any security therefor and of all books, records, papers and
documents of the Pledgor or in the Pledgor's possession or










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control relating to the Collateral that are not already in the Trustee's
possession. To the extent permitted by law, the Pledgor expressly waives any
notice of sale or other disposition of the Collateral and all other rights or
remedies of the Pledgor or formalities prescribed by law relative to sale or
disposition of the Collateral or exercise of any other right or remedy of the
Trustee existing after Default or Event of Default hereunder. To the extent any
such notice is required and cannot be waived, the Pledgor agrees that if such
notice is given in the manner provided in Section 17 hereof at least three days
before the time of the sale or disposition, such notice shall be deemed
reasonable and shall fully satisfy any requirement for giving of said notice.
The Trustee shall not be obligated to make any sale of Collateral regardless of
notice of sale having been given. The Trustee may adjourn any public or private
sale. The Pledgor further agrees to use its best efforts to do or cause to be
done all such other acts as may be necessary to effect the intention of this
Section 12.

               (b) All rights to marshalling of assets of the Pledgor, including
any such right with respect to the Collateral, are hereby waived by the Pledgor.
The Pledgor shall not contest or support any other person in contesting the
validity or priority of the security interests created under this Agreement.

               (c) Any money collected by the Trustee pursuant to this Section
12 shall be applied in the following order, at the date or dates fixed by the
Trustee and, in case of the distribution of such money on account of principal
(or premium, if any), upon presentation of the Notes and the notation thereon of
the payment if only partially paid and upon surrender thereof if fully paid:

               (i) FIRST:  to the payment of all amounts due the Trustee under
        Sections 11 and 13 hereof; and

               (ii) SECOND: to the payment of the amounts then due and unpaid
        for interest on the Notes, ratably, without preference or priority of
        any kind, according to the amounts due and payable on such Notes for
        interest; and

               (iii) THIRD: to the payment of the amounts then due and unpaid
        for principal of (and premium, if any) on the Notes, ratably without
        preference or priority of any kind, according to the amounts due and
        payable on such Notes for principal (and premium, if any); and










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               (iv) FOURTH:  to the Pledgor.

               The Trustee may fix a record date and payment date for any
payment to holders of the Notes pursuant to this Section 12. At least 15
calendar days before such record date, the Trustee at the expense of the Pledgor
shall send to each holder of a Note by first class mail, postage prepaid, a
notice prepared by the Pledgor that states such record date, the payment date
and amount to be paid.

               13. Fees and Expenses. The Pledgor shall, upon demand, pay to the
Trustee the amount of its fees (which shall be in an amount previously agreed to
by the Pledgor and the Trustee) and any and all reasonable expenses (including
the reasonable fees, expenses and disbursements of counsel, experts and agents
retained by the Trustee) that the Trustee may incur in connection with (i) the
administration of this Agreement, (ii) the custody or preservation of, or the
sale of, collection from or other realization upon, any of the Collateral, (iii)
the exercise or enforcement of any of the rights of the Trustee and the holders
of the Notes hereunder or (iv) the failure by the Pledgor to perform or observe
any of the provisions hereof. The obligations of the Pledgor under this Section
13 shall survive the resignation or removal of the Trustee and the termination
of this Agreement.

               14. Security Interest Absolute. All rights of the Trustee and the
holders of the Notes, and the security interests created hereunder, and all
obligations of the Pledgor hereunder, shall be absolute and unconditional
(except to the extent prohibited by law) irrespective of:

               (a) any lack of validity or enforceability of the Indenture or
        any other agreement or instrument relating thereto;

               (b) any change in the time, manner or place of payment of, or in
        any other term of, all or any of the Obligations, or any other amendment
        or waiver of or any consent to any departure from the Indenture;

               (c) any exchange, surrender, release or nonperfection of any
        Liens on any other collateral for all or any of the Obligations; or

               (d) any other circumstance that might otherwise constitute a
        defense available to, or a discharge of, the Pledgor in respect of the
        Obligations or of this Agreement.










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               15. Continuing Security Interest; Termination. (a) This Agreement
shall create a continuing security interest in and to the Collateral and shall
be binding upon the Pledgor, its successors and assigns, and shall inure,
together with the rights and remedies of the Trustee hereunder, to the benefit
of the Trustee and the holders of the Notes and their respective successors,
transferees and assigns.

               (b) This Agreement shall terminate upon the earliest of (i)
payment in full in cash in United States dollars of each of the Secured Payments
to the holders thereof under the terms of the Indenture, (ii) the date on which
all Obligations due and owing under the Indenture and the Notes have been paid
in full in the event such Obligations become due and payable prior to the
payment of any of the Secured Payments or (iii) the exercise by the Pledgor of
its, and the effectiveness in accordance with the terms of the, legal defeasance
option pursuant to Article Thirteen of the Indenture. At such time, the Trustee
shall, at the written request of the Pledgor, reassign and promptly redeliver to
the Pledgor all of the Collateral hereunder that has not been sold, disposed of,
retained or applied by the Trustee in accordance with the terms of this
Agreement and the Indenture; provided, however, that no Default or Event of
Default shall have occurred and be continuing. Such reassignment and redelivery
shall be without warranty (either express or implied) by or recourse to the
Trustee, except as to the absence of any prior assignments by the Trustee of its
interest in the Collateral, and shall be at the expense of the Pledgor.

               16. Authority of the Trustee. (a) The Trustee shall have and be
entitled to exercise all powers hereunder that are specifically granted to the
Trustee by the terms hereof, together with such powers as are reasonably
incident thereto. The Trustee may perform any of its duties hereunder or in
connection with the Collateral by or through agents or employees and shall be
entitled to retain counsel and to act in reliance upon the advice of counsel
concerning all such matters. None of the Trustee or any director, officer,
employee, attorney or agent of the Trustee shall be liable to the Pledgor for
any action taken or omitted to be taken by it or them hereunder, except for its
or their own negligent action, negligent failure to act or willful misconduct;
provided, however, that (i) each such person shall not be liable for any error
of judgment made in good faith by it unless it is proved that such person was
negligent in ascertaining the pertinent facts and (ii) the Trustee shall not be
liable with respect to any action it










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takes or omits to take in good faith in accordance with a direction or request
received by it pursuant to Section 5.12 of the Indenture or Section 16(d)
hereof. The Trustee shall not be responsible for the validity, effectiveness or
sufficiency hereof or of any document or security furnished pursuant hereto. The
Trustee and its directors, officers, employees, attorneys and agents shall be
entitled to rely on any communication, instrument or document believed by it or
them to be genuine and correct and to have been signed or sent by the proper
Person or Persons.

               (b) The Pledgor acknowledges that the rights and responsibilities
of the Trustee under this Agreement with respect to any action taken by the
Trustee or the exercise or nonexercise by the Trustee of any option, right,
request, judgment or other right or remedy provided for herein or resulting or
arising out of this Agreement shall, as between the Trustee and the holders of
the Notes, be governed by the Indenture and by such other agreements with
respect thereto as may exist from time to time among them, but, as between the
Trustee and the Pledgor, the Trustee shall be conclusively presumed to be acting
as agent for the holders of the Notes with full and valid authority so to act or
refrain from acting, and the Pledgor shall not be obligated or entitled to make
any inquiry respecting such authority.

               (c) The Trustee undertakes to perform such duties and only such
duties as are specifically set forth in this Agreement and no implied covenants
or obligations shall be read in this Agreement against the Trustee. The Trustee
shall not be deemed to have knowledge of a Default or an Event of Default under
the Indenture unless informed in writing by the Pledgor or the holder of any
Note or unless a officer of the Trustee shall have actual knowledge thereof.

               (d) The Trustee shall not be required to exercise any remedies
hereunder unless requested in writing to do so by the holders of not less than a
majority in principal amount of the outstanding Notes and only if furnished with
indemnity satisfactory to the Trustee. The Trustee may consult with counsel and
shall not be liable for any action taken in good faith in reliance upon advice
of counsel except for its bad faith, its own negligent action, its own negligent
failure to act or its own wilful misconduct. The Trustee makes no representation
or warranty and shall have no responsibility concerning the value or validity of
the Collateral or the validity or perfection of the pledge thereof.

               (e) Any resignation or removal of the Trustee under the Indenture
shall, upon the effective date thereof,










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result in the simultaneous resignation or removal, as the case may be, of the
Trustee hereunder and any appointment of a successor Trustee under the Indenture
shall, upon the effectiveness thereof, result in the simultaneous appointment of
the same successor Trustee hereunder.

               (f) The Trustee shall be deemed to have exercised reasonable care
in the custody and preservation of the Collateral in its possession if the
Collateral is accorded treatment substantially equal to that which a reasonable
person accords its own property, it being understood that neither the Trustee
nor the holders of the Notes shall have responsibility for (i) ascertaining or
taking action with respect to calls, conversions, exchanges, maturities, tenders
or other matters relative to any Collateral, whether or not any such Person has
or is deemed to have knowledge of such matters, or (ii) taking any necessary
steps to preserve rights against any parties with respect to any Collateral.

               (g) Notwithstanding anything herein to the contrary, the
exculpations, immunities and protections available to the Trustee under the
Indenture shall be available to the Trustee hereunder.

               17. Notices. Any communication, notice or demand to be given
hereunder shall be in writing and delivered in person or mailed by first class
mail, postage prepaid, addressed as follows: If to the Trustee: United States
Trust Company of New York, 114 West 47th St., New York, NY 10036, Attention:
Patricia Gallagher; if to the Company: CD Radio Inc., 1221 Avenue of the
Americas, 36th Floor, New York, New York 10020, Attention: Patrick L. Donnelly.
Notice may also be given in such other form and manner or to such other address
as shall be designated by any party hereto to each other party hereto in a
written notice delivered in accordance with the terms of the Indenture.

               18. No Waiver; Cumulative Rights. No failure on the part of the
Trustee to exercise, and no delay in exercising, any right, remedy or power
hereunder shall operate as a waiver thereof, nor shall any single or partial
exercise by the Trustee of any right, remedy or power hereunder preclude any
other or future exercise of any other right, remedy or power. Each and every
right, remedy and power hereby granted to the Trustee or allowed it by law or
other agreement shall be cumulative and not exclusive the one of any other, and
may be exercised by the Trustee from time to time.

               19. Benefits of Agreement. Nothing in this Agreement, whether
express or implied, shall give to any










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Person other than the parties hereto and their successors hereunder, and the
holders of the Notes, any benefit or any legal or equitable right, remedy or
claim under this Agreement.

               20. Applicable Law. THIS AGREEMENT AND THE RIGHTS AND OBLIGATIONS
OF THE PARTIES HEREUNDER SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE LAWS OF THE STATE OF NEW YORK WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES
OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER
JURISDICTION WOULD BE REQUIRED THEREBY.

               21. Execution in Counterparts. This Agreement may be executed in
any number of counterparts, each of which shall be an original, but such
counterparts shall together constitute one and the same instrument.

               22. Trust Indenture Act. The Pledgor shall provide the annual
opinion required by Section 314(b) of the Trust Indenture Act and shall comply
with Section 314(d) thereof, to the extent applicable, in connection with any
release or substitution of Collateral hereunder.










                                                                              15

               IN WITNESS WHEREOF, the parties hereto have caused this Agreement
to be duly executed all as of the day and year first above written.

                                          CD RADIO INC.

                                             by   /s/Patrick L. Donnelly
                                                  ------------------------------
                                                  Patrick L. Donnelly
                                                  Executive Vice President,
                                                  General Counsel and
                                                  Secretary

                                          UNITED STATES TRUST COMPANY OF
                                          NEW YORK, as Trustee,

                                            by    /s/Patricia Gallagher
                                                  ------------------------------
                                                  Name:  Patricia Gallagher
                                                  Title: Assistant Vice
                                                         President