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                                                                  Exhibit 10.6


                             SUPPLEMENTAL INDENTURE

                  This Supplemental Indenture, dated as of November 15, 2001
(this "SUPPLEMENTAL INDENTURE"), between XM Satellite Radio Inc., a Delaware
corporation (the "COMPANY"), and The Bank of New York (successor to United
States Trust Company of New York), as Trustee under the Indenture referred to
below.

                              W I T N E S S E T H:

                  WHEREAS, the Company and the Trustee have heretofore executed
and delivered an Indenture, dated as of March 15, 2000 (as amended,
supplemented, waived or otherwise modified, the "INDENTURE"), providing for the
issuance of 14% Senior Secured Notes due 2010 of the Company (the "NOTES");

                  WHEREAS, the Company and the Trustee desire to clarify certain
provisions of the Indenture; and

                  WHEREAS, pursuant to SECTION 9.01 of the Indenture, the
Trustee and the Company are authorized to execute and deliver this Supplemental
Indenture to amend the Indenture, without the consent of any Holder of Notes;

                  NOW, THEREFORE, in consideration of the foregoing and for
other good and valuable consideration, the receipt of which is hereby
acknowledged, the Company and the Trustee mutually covenant and agree for the
equal and ratable benefit of the holders of the Notes as follows:

                                    Article I
                                   DEFINITIONS

                  Section 1.1. DEFINED TERMS. As used in this Supplemental
Indenture, terms defined in the Indenture or in the preamble or recital hereto
are used herein as therein defined. The words "herein," "hereof" and "hereby"
and other words of similar import used in this Supplemental Indenture refer to
this Supplemental Indenture as a whole and not to any particular section hereof.

                                   Article II
                                   AMENDMENTS

                  Section 2.1. AMENDMENT AND RESTATEMENT OF SECTION 4.11.
Section 4.11 of the Indenture is hereby amended and restated in its entirety to
read as set forth below:

                  SECTION 4.11      TRANSACTIONS WITH AFFILIATES.

                           The Company shall not, and shall not permit any of
its Restricted Subsidiaries to, make any payment to, or sell, lease, transfer or
otherwise dispose of any of its properties or assets to, or purchase any
property or assets from, or enter into or make or amend any transaction,
contract, agreement, understanding, loan, advance or guarantee with, or for the
benefit of, any Affiliate (each, an "AFFILIATE TRANSACTION"), unless: (a) such
Affiliate Transaction



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is on terms that are no less favorable to the Company or the relevant Restricted
Subsidiary than those that would have been obtained in a comparable transaction
by the Company or such Restricted Subsidiary with an unrelated Person; and (b)
the Company delivers to the Trustee (i) with respect to any Affiliate
Transaction or series of related Affiliate Transactions involving aggregate
consideration in excess of $5.0 million, a resolution of the Board of Directors
set forth in an Officers' Certificate certifying that such Affiliate Transaction
complies with this covenant and, if an opinion meeting the requirements set
forth in clause (ii) of this paragraph has not been obtained, that such
Affiliate Transaction has been approved by a majority of the members of the
Board of Directors who have no direct financial interest in such Affiliate
Transaction (other than as a stockholder of the Company or Holdings), and (ii)
with respect to (x) any Affiliate Transaction or series of related Affiliate
Transactions involving aggregate consideration in excess of $20.0 million, or
(y) any Affiliate Transaction or series of related Affiliate Transactions
involving aggregate consideration in excess of $5.0 million where none of the
members of the Board of Directors qualify as having no direct financial interest
in such Affiliate Transaction (other than as a stockholder of the Company or
Holdings), an opinion as to the fairness to the Company or such Restricted
Subsidiary of such Affiliate Transaction from a financial point of view issued
by an accounting, appraisal or investment banking firm of national standing;
PROVIDED HOWEVER that the following items shall not be deemed to be Affiliate
Transactions and, therefore, will not be subject to the provisions of this
paragraph:

                  (1) any transaction by the Company or any Restricted
Subsidiary with an Affiliate directly related to the purchase, sale or
distribution of products in the ordinary course of business consistent with
industry practice which has been approved by a majority of the members of the
Board of Directors who are disinterested with respect to such transaction;

                  (2) any employment agreement or arrangement or employee
benefit plan entered into by the Company or any of its Restricted Subsidiaries
in the ordinary course of business of the Company or such Restricted Subsidiary;

                  (3) transactions between or among the Company and/or its
Restricted Subsidiaries;

                  (4) payment of reasonable directors fees and provisions
of customary indemnification to directors, officers and employees of the Company
and its Restricted Subsidiaries;

                  (5) sales of Equity Interests (other than Disqualified
Stock) to Affiliates of the Company;

                  (6) Restricted Payments that are permitted by the
provisions of Section 4.07 hereof and under clauses (8) and (9) of the
definition of "Permitted Investments";

                  (7) transactions pursuant to the Tax Sharing Agreement;
and

                  (8) contractual arrangements existing on the date hereof, and
any renewals, extensions, implementations or modifications thereof that are not
materially adverse to the Holders.


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                                   Article III
                                  MISCELLANEOUS

                  Section 3.1. PARTIES. Nothing expressed or mentioned herein is
intended or shall be construed to give any Person, firm or corporation, other
than the Holders and the Trustee, any legal or equitable right, remedy or claim
under or in respect of this Supplemental Indenture or the Indenture or any
provision herein or therein contained.

                  Section 3.2. GOVERNING LAW. This Supplemental Indenture shall
be governed by, and construed in accordance with, the laws of the State of New
York, but without giving effect to applicable principles of conflicts of law to
the extent that the application of the law of another jurisdiction would be
required thereby. This Supplemental Indenture shall be governed and construed in
accordance with the applicable terms and provisions of the Indenture as amended
hereby, which terms are incorporated herein by reference, as if this
Supplemental Indenture were the "Indenture" referred to therein.

                  Section 3.3. SEVERABILITY CLAUSE. In case any provision in
this Supplemental Indenture shall be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in
any way be affected or impaired thereby and such provision shall be ineffective
only to the extent of such invalidity, illegality or unenforceability.

                  Section 3.4. RATIFICATION OF INDENTURE; SUPPLEMENTAL
INDENTURES PART OF INDENTURE. Except as expressly amended hereby, the Indenture
is in all respects ratified and confirmed and all the terms, conditions and
provisions thereof shall remain in full force and effect. This Supplemental
Indenture shall form a part of the Indenture for all purposes, and every holder
of Notes heretofore or hereafter authenticated and delivered shall be bound
hereby.

                  Section 3.5.  COUNTERPARTS.  The parties hereto may sign one
or more copies of this Supplemental Indenture in counterparts, all of which
together shall constitute one and the same agreement.

                  Section 3.6.  HEADINGS.  The headings of the Articles and the
Sections in this Supplemental Indenture are for convenience of reference only
and shall not be deemed to alter or affect the meaning or interpretation of any
provisions hereof.

                  Section 3.7 NOTATION ON NOTES. Pursuant to Section 9.05 of the
Indenture, new Notes reflecting the amendments to the Indenture made hereby
shall not be issued; however, corresponding changes to the Notes to reflect the
amendments made hereby shall be deemed to be made to the Notes as of the date of
this Supplemental Indenture. The Trustee may, but shall not be required to,
place an appropriate notation as to this Supplemental Indenture on any Note
hereafter authenticated in accordance with Section 9.05 of the Indenture.


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                  IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed as of the date first above written.

                                      XM SATELLITE RADIO INC.


                                      By:
                                          --------------------------------------
                                          Name:
                                          Title:


Attest:




-------------------------------
Name:
Title:

                                      THE BANK OF NEW YORK, AS TRUSTEE


                                      By
                                          --------------------------------------
                                          Name:
                                          Title:

Attest:




-------------------------------
Authorized Signatory
Date: