<Page>

                                                                     EXHIBIT 8.1

                      [HOGAN & HARTSON L.L.P. LETTERHEAD]

                                 August 8, 2003


XM Satellite Radio Inc.
1500 Eckington Place NE
Washington, D.C.  20002-2194

Ladies and Gentlemen:

          This firm has acted as special counsel to XM Satellite Radio Inc., a
Delaware corporation (the "Company"), in connection with its Registration
Statement on Form S-4 (the "Registration Statement"), filed with the Securities
and Exchange Commission and relating to the proposed offering of up to
$185,000,000 in aggregate principal amount of 12% Senior Secured Notes due 2010
(the "Exchange Notes") in exchange for up to $185,000,000 in aggregate principal
amount of the Company's outstanding 12% Senior Secured Notes due 2010 (the
"Senior Notes"). This opinion letter is furnished to you at your request to
enable you to fulfill the requirements of Item 601(b)(8) of Regulation S-K, 17
C.F.R. Section 229.601(b)(8), in connection with the Registration Statement.
Capitalized terms used in this letter and not otherwise defined herein shall
have the meaning set forth in the prospectus ("Prospectus") included as part of
the Registration Statement.

          This opinion letter is based as to matters of law solely on the
Internal Revenue Code of 1986, as amended, its legislative history, judicial
authority, current administrative rulings and practice, and existing and
proposed Treasury Regulations, all as in effect and existing on the date hereof
(collectively, "federal tax laws"). These provisions and interpretations are
subject to changes, which may or may not be retroactive in effect, that might
result in material modifications of our opinion. We express no opinion herein as
to any other laws, statutes, regulations, or ordinances. Our opinion does not
foreclose the possibility of a contrary determination by the Internal Revenue
Service (the "IRS") or a court of competent jurisdiction, or of a contrary
position by the IRS or the Treasury Department in regulations or rulings issued
in the future. In this regard, although we believe that our opinion set forth
herein will be sustained if challenged, an opinion of counsel with respect to an
issue is not binding on the IRS or the courts, and is not a

<Page>

XM Satellite Radio, Inc.
August 8, 2003
Page 2

guarantee that the IRS will not assert a contrary position with respect to such
issue or that a court will not sustain such a position asserted by the IRS.

          In rendering the following opinion, we have examined such statutes,
regulations, records, certificates and other documents as we have considered
necessary or appropriate as a basis for such opinion, including (but not limited
to) the following: (i) the Registration Statement; (ii) the forms of the Senior
Notes and the Exchange Notes; (iii) the Registration Rights Agreement; and (iv)
an executed copy of the Indenture.

          In our review, we have assumed that all of the representations and
statements set forth in such documents are true and correct, and all of the
obligations imposed by any such documents on the parties thereto have been and
will continue to be performed or satisfied in accordance with their terms. We
also have assumed the genuineness of all signatures, the proper execution of all
documents, the accuracy and completeness of all documents submitted to us, the
authenticity of all original documents, and the conformity to authentic original
documents of all documents submitted to us as copies (including telecopies).
This opinion letter is given, and all statements herein are made, in the context
of the foregoing.

          For purposes of rendering our opinion, we have not made an independent
investigation of the facts set forth in any of the above-referenced documents,
including the Prospectus. We have consequently relied upon representations and
information presented in such documents.

          Based upon, and subject to, the foregoing, we are of the opinion that
the discussion in the Prospectus under the heading "Certain United States
Federal Income Tax Considerations," to the extent that it purports to describe
provisions of federal income tax law or legal conclusions with respect thereto,
is correct in all material respects as of the date hereof.

          We assume no obligation to advise you of any changes in the foregoing
subsequent to the delivery of this opinion letter. This opinion letter has been
prepared solely for your use in connection with the filing of the Registration
Statement on the date of this opinion letter and should not be quoted in whole
or in part or otherwise referred to, nor filed with or furnished to, any other
governmental agency or other person or entity without the prior written consent
of this firm.

<Page>

XM Satellite Radio, Inc.
August 8, 2003
Page 3

          We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In giving such consent, we do not admit that we are in
the category of persons whose consent is required under Section 7 of the
Securities Act of 1933, as amended.

                                         Very truly yours,

                                         /s/ Hogan & Hartson L.L.P.

                                         HOGAN & HARTSON L.L.P.