<PAGE>
 
                                                                    EXHIBIT 10.2

                         PLEDGE AND SECURITY AGREEMENT

     THIS PLEDGE AND SECURITY AGREEMENT (this "Agreement") is made on and as of
this 28th day of April, 1999, by and among TCI Satellite Entertainment, Inc., a
Delaware corporation, as pledgor ("Pledgor"), PRIMESTAR, Inc., a Delaware
corporation, as the initial secured party ("Primestar"), and The Bank of New
York, as collateral agent (the "Collateral Agent").

                                 RECITALS

     A.  Reference is made to the Share Appreciation Right Agreement ("SAR
Agreement"), dated as of the date hereof, between Pledgor and Primestar.  This
Agreement is the Pledge and Security Agreement referred to in the SAR Agreement.
Capitalized terms used in this Agreement and not defined herein have the
meanings ascribed to such terms in the SAR Agreement.

     B.  The SAR Agreement provides for the issuance by Pledgor to Primestar of
share appreciation rights ("SARs"), on the terms set forth therein, with respect
to an aggregate of  1,407,307 shares (the "GMH Shares") of the Class H Common
Stock of General Motors Corporation ("GMH Stock") being acquired concurrently
herewith by the Pledgor.

     C.  Pledgor desires to grant to the Collateral Agent, for the benefit of
Primestar and its successors and permitted assigns (collectively, the "Secured
Party") a pledge of and security interest in all of Pledgor's right, title and
interest in, to and under the Collateral (as defined herein) from time to time
pledged hereunder, to secure (i) the full and timely payment by Pledgor to the
Secured Party, on the terms and subject to the conditions set forth in the SAR
Agreement, of the obligations of Pledgor thereunder and (ii) the payment of the
reasonable costs and expenses (including, without limitation, attorneys' fees
and expenses) incurred by the Collateral Agent or the Secured Party in
connection with enforcing its rights under this Agreement after an Event of
Default (as defined herein) has occurred (collectively, the "Secured
Obligations") on the Settlement Date (as defined in the SAR Agreement).

     D.  Concurrently with the execution and delivery of this Agreement,
Primestar is entering into the Primestar Pledge and Security Agreement and is
granting to The Bank of New York, as the collateral agent under the Primestar
Pledge and Security Agreement (the "Primestar PSA Collateral Agent"), a security
interest in (i) the SAR Agreement  and (ii) all Primestar's rights, title and
interests as secured party under this Pledge and Security Agreement and the
security interest in the GMH Shares granted herein (collectively, "Primestar's
Pledged Rights").
<PAGE>
 
     NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, and intending to be bound hereby, the parties hereto hereby agree
as follows:

     1.  Grant of Security Interest.  The Pledgor hereby assigns, pledges,
         --------------------------                                       
transfers and grants to the Collateral Agent, on behalf of and for the benefit
of the Secured Party, a security interest in all of Pledgor's right, title and
interest in, to and under the property described in Section 2 below
(collectively, the "Collateral"), to secure the full and timely payment by
Pledgor of the Secured Obligations.

     2.  Collateral.  The Collateral shall consist of all right, title and
         ----------                                                       
interest of the Pledgor in, to and under each of the following, in each case
whether now owned or existing or hereafter acquired or arising:

         (a)  1,407,307 shares of GMH Stock represented by certificate number
              CHF086306;

         (b)  The Cash Collateral Account (as defined in Section 8), any and
              all funds at any time held in such account, and any and all
              rights of the Pledgor to payments made in respect of such
              account; and

         (c)  All proceeds of any of the foregoing.

     3.  Appointment of Custodian.  The Pledgor hereby appoints the Collateral
         ------------------------                                             
Agent to act as agent, bailee and custodian for the benefit of the Pledgor and
the Secured Party as their respective interests shall appear with respect to the
Collateral. The Collateral Agent hereby accepts such appointment and agrees to
maintain and hold all Collateral at any time delivered to it as agent, bailee
and custodian for the benefit of the Pledgor and the Secured Party in accordance
with the terms of this Agreement.  The Collateral Agent agrees to act in
accordance with this Agreement and in accordance with any written instructions
properly delivered hereunder. The Collateral Agent shall deliver possession of
the Collateral to the Pledgor or any other person named by Pledgor, or otherwise
release any Collateral from the lien created hereby, only in accordance with the
express terms of this Agreement or otherwise upon the written instruction of the
Pledgor and/or the Secured Party, as applicable.

     4.  Certain Actions to Maintain Perfection of Security Interest.  The
         -----------------------------------------------------------      
Pledgor agrees (i) that the lien created or purported to be created hereunder
shall at all times be valid and enforceable against the Pledgor and all third
parties, in accordance with the terms hereof, as security for the Secured
Obligations, (ii) that the lien created by this Agreement with respect to the
Collateral shall be a first priority perfected lien, and (iii) that the
Collateral shall not at any time be subject to any other lien, except that
Primestar may subject its interest in the Collateral to a lien as contemplated
by Section 27 of this Agreement and the Primestar Pledge and Security Agreement.
The Pledgor shall take all action that may be necessary or desirable so as at
all times 

                                       2
<PAGE>
 
(a) to maintain the validity, perfection, enforceability and priority of the
liens created or purported to be created hereunder in conformity with the
requirements of the immediately preceding sentence, (b) to protect and preserve
the Collateral and (c) to protect and preserve, and to enable the exercise and
enforcement of, the rights of the Secured Party therein and hereunder.

     5.  Delivery of Collateral.  Pledgor agrees that the GMH Shares and any
         ----------------------                                             
other certificated securities that may from time constitute Collateral hereunder
shall be evidenced by certificates, and that all such certificates shall be
accompanied by stock powers, executed in blank, or by other proper instruments
of assignment duly executed by Pledgor, and by any such other instruments or
documents as the Collateral Agent may reasonably request.

     6.  Custody of Collateral.  Upon the Collateral Agent's receipt of the
         ---------------------                                             
Collateral, the Collateral Agent shall retain exclusive possession and custody
thereof, subject to the terms of this Agreement (including, without limitation,
Section 27 hereof), for purposes of perfecting the security interest therein of
the Secured Party. The Collateral Agent shall make appropriate notations in its
books and records to reflect that the Collateral contained therein has been
pledged to the Secured Party and is held by the Collateral Agent for the benefit
of the Pledgor and the Secured Party as their respective interests appear
hereunder.  Except as otherwise expressly provided in this Agreement, all
instruments representing Collateral shall be (i) held by the Collateral Agent in
fire-proof vaults, safe deposit boxes or file cabinets under its exclusive
custody and control and (ii) segregated from all such documents held by The Bank
of New York for its own account or for the account of other persons. The
Collateral Agent shall not have any duty to collect dividends, or other amounts
due or to become due on any Collateral or, except as expressly set forth herein,
to take any action to preserve any rights of the Pledgor or the Secured Party as
against any person obligated with respect to any Collateral.

     7.  Release of Collateral.  During the term of this Agreement, the
         ---------------------                                         
Collateral shall be released only as follows:

          (a) From the Determination Date through the Termination Date, so long
     as no Event of Default shall have occurred and be continuing, the
     Collateral Agent shall (i) release to the Pledgor for sale or otherwise, or
     (ii) sell in accordance with the instructions of the Pledgor, in either
     case promptly upon Pledgor's written request, all or any portion of the
     Collateral that constitutes Covered Shares; provided that, in the case of
                                                 --------                     
     any release pursuant to clause (i) of this subsection, Pledgor shall
     simultaneously deposit or cause to be deposited into the Cash Collateral
     Account (as defined below), and in the case of any sale by the Collateral
     Agent pursuant to clause (ii) of this subsection, the Collateral Agent
     shall deposit into the Cash Collateral Account out of the proceeds of such
     sale, in cash, an amount equal to the product of (A) the Per Share
     Settlement Amount times (B) the number of Covered Shares so sold or
                       -----                                            
     released.

          (b) On the Settlement Date, the Collateral Agent shall pay, by wire
     transfer of immediately available funds, the Aggregate Settlement Amount
     owing to the Secured 

                                       3
<PAGE>
 
     Party under the SAR Agreement pursuant to instructions, which shall include
     the Aggregate Settlement Amount and wire transfer instructions certified in
     writing to the Collateral Agent two business days prior to the Settlement
     Date by the Pledgor, or, during an Event of Default, the Secured Party.
     Payment of the Aggregate Settlement Amount pursuant to this Section 7(b)
     shall be made first, from amounts on deposit in the Cash Collateral Account
                   -----
     at the end of the business day preceding the Settlement Date, including
     cash, if any, that Pledgor has deposited in the Cash Collateral Account to
     enable the payment of the Aggregate Settlement Amount hereunder, and
     second, from the proceeds of the sale by the Collateral Agent, at the
     ------
     instruction of the Pledgor or, during an Event of Default, the Secured
     Party, of such amount of Pledged Securities (as defined in Section 9) as
     shall be required to enable the Collateral Agent to pay the Aggregate
     Settlement Amount. Any amounts realized from a sale of Pledged Securities
     in excess of the amount required to pay the Aggregate Settlement Amount
     owing on the Settlement Date and any other Secured Obligations hereunder
     shall be deposited in the Cash Collateral Account and distributed in
     accordance with Section 7(c).

          (c)     On the first business day following the date all obligations
of the Pledgor under the SARs shall have been satisfied or discharged in full
(the "Termination Date"), the lien and security interest created by this
Agreement on and in the Collateral shall automatically be  released, and the
entire Collateral, including without limitation all amounts in the Cash
Collateral Account, shall be returned to the Pledgor on or promptly following
such date, and the Collateral Agent shall execute and deliver such agreements,
termination statements or other documents or filings as the Pledgor shall
reasonably request to evidence or effect the release of such lien and security
interest.

     8.  Cash Collateral Account.  All cash proceeds of any Collateral
         -----------------------                                      
hereunder, including, without limitation, all cash distributions and dividends
with respect to such Collateral, and all amounts paid by or on behalf of the
Pledgor pursuant to Section 7(a)(i) shall be paid directly to a "no access"
account of the Pledgor maintained with the Collateral Agent (the "Cash
Collateral Account"). Until the Termination Date, the Cash Collateral Account
shall be under the exclusive dominion and control of the Collateral Agent for
the ratable benefit of each of the Secured Party, and any transfer or withdrawal
of funds therefrom shall be governed by this Agreement.  On the Termination
Date, all amounts on deposit in the Cash Collateral Account shall be paid to the
Pledgor in accordance with Section 7(c) hereof.

     9.  Rights of Pledgor With Respect to The Collateral.  Notwithstanding
         ------------------------------------------------                  
Pledgor's pledge of the Collateral under this Agreement, Pledgor shall have
during the term of this Agreement, except as expressly set forth to the contrary
in this Agreement, all rights associated with the ownership of the Collateral,
including, without limitation, in the case of the GMH Shares and any other
securities from time to time constituting Collateral (collectively, "Pledged
Securities"), (a) all voting and consensual rights relating to Pledged
Securities and (b) the right to make any election to which a holder of Pledged
Securities may become entitled with respect to any dividend or distribution on,
or conversion, exchange, reclassification or other change to, such 

                                       4
<PAGE>
 
Pledged Securities, including without limitation any election with respect to
the consideration to be received in any merger affecting the issuer of such
Pledged Securities, together with all other rights now or hereafter associated
with ownership of any Pledged Securities.

     10.  Sale of Collateral.  Upon any sale or other disposition of the
          ------------------                                            
Collateral pursuant to this Agreement, upon Event of Default or otherwise, the
Collateral Agent shall have the right to deliver, assign and transfer to the
purchaser thereof (including the Pledgor) the Collateral or portion thereof so
sold or disposed of and all proceeds thereof shall be promptly transmitted to
the Collateral Agent for application by the Collateral Agent in accordance with
Section 7 of this Agreement.   Each purchaser (including Pledgor) at any such
sale or other disposition shall hold the Collateral free from any claim or right
of whatever kind. The Pledgor hereby specifically waives (to the extent
permitted by law) all rights of stay or appraisal which it has or may have under
any rule of law or statute now existing or hereafter adopted.  Nothing herein
contained shall be construed as an assumption by the Collateral Agent, the
Secured Party or any of their respective appointees of any liability of the
Pledgor with respect to any of the Collateral, and the Pledgor shall be and
remain responsible for all such liabilities. Pledgor hereby acknowledges that
any sale by the Collateral Agent of any Pledged Securities must be made in
compliance with the Securities Act of 1933 (the "Securities Act"), all other
Federal securities laws, as well as any applicable Blue Sky or other state
securities laws which may impose limitations as to the manner in which a Secured
Party or any other person may sell, transfer or otherwise dispose of securities.
Pledgor acknowledges that any sale or disposition contemplated pursuant hereto
may be at prices and on terms less favorable to the Secured Party than those
obtainable through a public sale without any applicable restrictions, and,
notwithstanding such circumstances, Pledgor agrees that any such sale or other
disposition shall be deemed to have been made in a commercially reasonable
manner.

     11.  Standard of Care of Collateral Agent; Duties; Indemnification.  The
          -------------------------------------------------------------      
Collateral Agent is a bailee for hire and shall hold the Collateral in
accordance with customary standards for those engaged as custodians of
commercial documents in similar capacities. Notwithstanding anything to the
contrary contained herein:

          (a) The provisions of this Agreement set forth the exclusive duties of
     the Collateral Agent and no implied duties or obligations shall be read
     into this Agreement against the Collateral Agent. The Collateral Agent
     shall not be bound in any way by any agreement or contract other than this
     Agreement and any other agreement to which it is a party. The Collateral
     Agent shall not be required to ascertain or inquire as to the performance
     or observance of any of the conditions or agreements to be performed or
     observed by any other party, except as specifically provided in this
     Agreement. The Collateral Agent disclaims any responsibility for the
     validity or accuracy of the recitals to this Agreement and any
     representations and warranties contained herein, unless specifically
     identified as recitals, representations or warranties of the Collateral
     Agent.

                                       5
<PAGE>
 
          (b) Throughout the term of this Agreement, the Collateral Agent shall
     have no responsibility for ascertaining the value of any Collateral, the
     title of any party therein, the validity or adequacy of the security
     afforded thereby, or the validity of this Agreement (except as to
     Collateral Agent's authority to enter into this Agreement and to perform
     its obligations hereunder).

          (c) The Collateral Agent shall not be under any duty to examine or
     pass upon the genuineness, validity or legal sufficiency of any of the
     documents constituting part of the Collateral, and shall be entitled to
     assume that all documents constituting part of such Collateral are genuine
     and valid and that they are what they purport to be, and that any
     endorsements or assignments thereof are genuine and valid. The Collateral
     Agent may rely upon and shall be protected in acting in good faith upon any
     notice, resolution, request, consent, order, certificate, report, statement
     or other paper or document appearing on its face to be genuine and to have
     been signed or presented by the proper party or parties or by a person or
     persons authorized to act on behalf of the proper party or parties.  The
     Collateral Agent shall not be liable for any action or omission to act as
     bailee except for its own gross negligence or willful misconduct.

          (d) No provision of this Agreement shall require the Collateral Agent
     to expend or risk its own funds or otherwise incur any financial liability
     in the performance of any of its duties hereunder or in the exercise of any
     of its rights or powers, if, in its sole judgment, it shall believe that
     repayment of such funds or adequate indemnity against such risk or
     liability is not assured to it.

          (e) The Collateral Agent is not responsible for preparing or filing
     any reports or returns relating to Federal, state or local income taxes
     with respect to this Agreement, other than for the Collateral Agent's
     compensation or for reimbursement of expenses.

          (f) The Pledgor agrees to reimburse and hold harmless the Collateral
     Agent, its directors, officers, employees and agents from and against any
     and all liability, damage, claim (whether asserted by the Pledgor, the
     Secured Party or any other person) and loss and reasonable out-of-pocket
     expenses (including reasonable counsel fees and expenses) arising from or
     connected with the Collateral Agent's execution and performance of this
     Agreement, including the claims of any third parties (including any
     assignee) relating to the Collateral Agent's execution and performance of
     this Agreement, except in any such case for any liability, damage, claim,
     loss or expense resulting from gross negligence or willful misconduct on
     the part of the Collateral Agent.

          (g) The Collateral Agent shall have the power to employ such agents as
     it may deem necessary or appropriate in the performance of its duties and
     the exercise of its powers under this Agreement and shall not be liable for
     the acts or omissions of any agent appointed with due care by it hereunder.

                                       6
<PAGE>
 
          (h) Notwithstanding anything to the contrary herein, this Section 11
shall survive the termination of this Agreement.

     12.  Fees and Expenses of Collateral Agent.  The Collateral Agent shall
          -------------------------------------                             
notify the Pledgor of all fees, expenses and charges of the Collateral Agent
arising out of the Collateral Agent's execution and performance of its duties
and obligations under this Agreement, and such reasonable fees, expenses and
charges shall be paid promptly by the Pledgor.  The Collateral Agent may employ,
at the Pledgor's reasonable expense, such legal counsel and other experts as it
deems necessary in connection with performing its duties and obligations under
this Agreement.  Notwithstanding anything to the contrary contained herein, this
provision shall survive the termination of this Agreement.

     13.  Removal or Resignation of Collateral Agent.  Pledgor, with the consent
          ------------------------------------------                            
of the Secured Party may at any time remove and discharge the Collateral Agent
from the performance of its duties under this Agreement.  Any such removal shall
be effective immediately if such termination is for cause or upon not less than
30 days' prior written notice to the Collateral Agent if such termination is
without cause.  In addition, the Collateral Agent may, at any time, effective
upon 30 days' prior written notice to the Pledgor and the Secured Party of the
appointment of a successor Collateral Agent, terminate its agreement to act as
the Collateral Agent under both this Agreement and the Primestar Pledge and
Security Agreement.  Upon the date of any such termination, the Collateral Agent
shall promptly deliver the Collateral then held by it or its agents to the
successor Collateral Agent and shall execute and shall promptly deliver, upon
payment of all amounts owed it hereunder, such notices, instructions and
assignments as may be reasonably necessary or desirable to transfer the rights
of the Collateral Agent with respect to the Collateral to the successor
Collateral Agent.  The appointment of the Collateral Agent by the Pledgor
pursuant to Section 3 above shall constitute the appointment of any successor
Collateral Agent designated pursuant to this Section 13.

     14.  Availability of Documents. Each of the Pledgor, the Secured Party and
          -------------------------                                            
their respective agents, accountants, attorneys and auditors will be permitted
during normal business hours at any time and from time to time upon reasonable
notice to the Collateral Agent to examine (to the extent permitted by applicable
law) the files, documents, records and other papers in the possession or under
the control of the Collateral Agent relating to any or all of the Collateral and
to make copies thereof.  All costs and expenses associated with the exercise
from time to time by the Pledgor or the Secured Party of its rights under this
Section 14 shall be for the account of the Pledgor or the Secured Party, as
applicable.

     15.  Representations and Warranties of Pledgor.  The Pledgor hereby
          -----------------------------------------                     
represents and warrants that: (a) the Pledgor is the sole owner of the
Collateral (or, in the case of after acquired Collateral, at the time the
Pledgor acquires rights in the Collateral, will be the sole owner thereof); (b)
except for the lien granted hereunder to the Secured Party and the lien granted
by Primestar on its interest in the Collateral under the Primestar Pledge and
Security Agreement to the Secured Parties thereunder, no Person has (or, in the
case of after-acquired Collateral, at the 

                                       7
<PAGE>
 
time the Pledgor acquires rights therein, will have) any right, title, claim or
interest (by way of security interest or other lien or charge or otherwise) in,
against or to all or any of the Collateral; (c) no consent of any other Person
is required for the grant of the security interest provided herein by the
Pledgor in any of the Collateral (except for any consent of Hughes Electronics
Corporation or General Motors Corporation, which has been received), nor will
any consent need to be obtained for the Secured Party to exercise its rights
with respect to any of the Collateral, and (d) no filings, except for such
filings as have been made, are being made concurrently with the execution of
this Agreement, or will be made by the Pledgor within the time period required
by applicable law, are required to perfect the lien granted by this Agreement.

     16.  Covenants of Pledgor. The Pledgor hereby agrees: (a) to procure,
          --------------------                                            
execute and deliver from time to time any and all endorsements, assignments,
financing statements, notices and other writings necessary or appropriate to
perfect, maintain and protect the Collateral Agent's security interest hereunder
and the priority thereof and to deliver promptly to the Collateral Agent all
originals of Collateral or proceeds consisting of chattel paper or instruments;
(b) not to surrender or lose possession of (other than to the Collateral Agent
or as otherwise permitted by this Agreement), sell, encumber, or otherwise
dispose of or transfer, any Collateral or right or interest therein other than
as otherwise permitted under this Agreement; (c) to account fully for and
promptly to deliver to the Collateral Agent, in the form received, all proceeds
received, endorsed to the Collateral Agent as appropriate and accompanied by
such assignments and powers, duly executed, as the Collateral Agent shall
request, and until so delivered all Collateral and proceeds shall be held in
trust for the Collateral Agent, separate from all other property of the Pledgor
and identified as being subject to the interest of the Collateral Agent; (d) not
to move its chief executive office to a new location unless (i) the Secured
Party shall have approved such move in writing or (ii) (A) the Pledgor shall
have given the Secured Party not less than 20 days prior notice thereof, (B) the
new location shall be within one of the 50 States of the United States or the
District of Columbia and (C) the Collateral Agent shall have received such
evidence reasonably satisfactory to it as it may reasonably request (including
acknowledgment copies of financing statements and opinions of counsel) that
Pledgor's rights with respect to the Collateral will not be adversely affected
by such move; (e) to do, to the extent permitted by this Agreement, all acts to
maintain, preserve and protect the Collateral that an owner of assets of the
same type as the Collateral would deem customarily necessary or desirable
therefor; and (f) to appear in and defend, at the Pledgor's cost and expense,
any action or proceeding which may affect its title to or the Secured Party's
interest in the Collateral.

     17.  Authorized Action by Collateral Agent.  The Pledgor hereby irrevocably
          -------------------------------------                                 
appoints the Collateral Agent as its attorney-in-fact, coupled with an interest,
to do (but the Collateral Agent shall not be obligated to and shall incur no
liability to the Pledgor or any third party for not so doing), at the request
and direction of the Secured Party upon the occurrence of an Event of Default
and while such Event of Default is continuing, any act which the Pledgor is
obligated by this Agreement to do, and to exercise such rights and powers as the
Pledgor might exercise with respect to the Collateral, including the right to
(a) collect by legal proceedings or otherwise and endorse, receive and receipt
for all interest, payments, proceeds and other sums and property 

                                       8
<PAGE>
 
now or hereafter payable on or on account of the Collateral; (b) preserve the
Collateral; (c) transfer the Collateral to the Collateral Agent's own or its
nominee's name; or (d) sell or otherwise dispose of the Collateral (provided
                                                                    --------
that nothing in this Section 17 shall limit the power of the Collateral Agent to
----                                                                            
sell Pledged Securities as provided in this Agreement).  Notwithstanding
anything contained herein, in no event shall the Collateral Agent or the Secured
Party be required to make any presentment, demand or protest or give any notice,
and neither the Collateral Agent nor the Secured Party need take any action to
preserve any rights against any prior party or any other person in connection
with the Secured Obligations or with respect to the Collateral. The Collateral
Agent is, and shall at all times continue to be, authorized to file financing
statements (and amendments to, and continuation statements in respect of,
financing statements) with respect to the Collateral without the signature of
the Pledgor in such filing offices as shall be necessary or appropriate for the
purpose of perfecting or maintaining the perfection of the security interest
provided for herein. The Collateral Agent shall give the Pledgor a copy of each
filing so made prior thereto or promptly thereafter.

     18.  Default and Remedies.
          -------------------- 

          (a) As used herein, the term "Event of Default" means the occurrence
     of any of the following events:

               (i)   the Pledgor's failure to pay or cause to be paid, when due,
          to or for the account of the Secured Party, the Aggregate Settlement
          Amount and any other outstanding Secured Obligations payable to the
          Secured Party in respect of the SARs, as provided in the SAR
          Agreement;

               (ii)  any representation of the Pledgor in this Agreement shall
          have been untrue in any material respect when made;

               (iii) the Pledgor shall breach in any material respect any
          covenant of the Pledgor in this Agreement;

               (iv)  the Pledgor shall make an assignment for the benefit of
          creditors or admit in writing its inability to pay its debts as they
          mature or come due, or shall petition or apply for the appointment of
          a trustee or other custodian, liquidator or receiver, or shall
          commence any case or other proceeding under any bankruptcy,
          reorganization, arrangement, insolvency , readjustment of debt,
          dissolution or liquidation or similar law of any jurisdiction, now or
          hereafter in effect, or if any such case or other proceeding shall be
          commenced against the Pledgor, the Pledgor shall indicate its approval
          thereof, consent thereto or acquiescence therein or such petition or
          application shall not have been dismissed within 90 days after the
          filing thereof; or

                                       9
<PAGE>
 
               (v)   a decree or order shall be entered appointing any such
          trustee, custodian, liquidator or receiver or adjudicating the Pledgor
          bankrupt or insolvent, or approving a petition in any such case or
          other proceeding, or a decree or order for relief is entered in
          respect of the Pledgor in a case under Federal bankruptcy laws as now
          or hereafter constituted.

          (b) On or after the Determination Date, upon the occurrence and during
     the continuation of any Event of Default (whether such Event of Default
     first occurred before or on or after the Determination Date), the
     Collateral Agent, upon request of the Secured Party, shall:  (i) foreclose
     or otherwise enforce the Secured Party's lien in the Collateral in any
     manner permitted by law or provided for hereunder; or sell or otherwise
     dispose of the Collateral or any part thereof at one or more public or
     private sales, for credit or future delivery (without the assumption of any
     credit risk), on such terms and in such manner as the Collateral Agent may
     determine to be commercially reasonable (taking into account the
     circumstances under which the Collateral is being sold); and (ii) pay and
     distribute to the Secured Party out of the Cash Collateral Account (and
     against delivery of the SAR Agreement or such other evidence as the
     Collateral Agent shall reasonably request), any and all amounts then due
     and payable to the Secured Party in respect of the SARs, which amounts
     shall be satisfied and discharged to the extent of any such payments
     actually received.

     19.  Cumulative Rights. The rights, powers and remedies of the Collateral
          -----------------                                                   
Agent and the Secured Party under this Agreement shall be in addition to all
rights, powers and remedies given to the Collateral Agent and the Secured Party
by virtue of any statute or rule of law, the SAR Agreement or any other
agreement, all of which rights, powers and remedies shall be cumulative and may
be exercised successively or concurrently. Without limiting the generality of
the foregoing, the Collateral Agent shall have all rights of a secured party
under the New York Uniform Commercial Code and other applicable New York law.

     20.  Waiver. Any waiver, forbearance, failure or delay by the Collateral
          ------                                                             
Agent or the Secured Party in exercising, or the exercise or beginning of
exercise by the Collateral Agent or the Secured Party of, any right, power or
remedy, simultaneous or later, shall not preclude the further, simultaneous or
later exercise thereof, and every right, power or remedy of the Collateral Agent
or the Secured Party shall continue in full force and effect.

     21.  Binding Upon Successors.  All rights and obligations of the Pledgor,
          -----------------------                                             
the Collateral Agent and the Secured Party under this Agreement shall bind and
inure to the benefit of the Pledgor, the Collateral Agent and the Secured Party
and their respective successors and assigns.

     22.  Entire Agreement; Severability.  This Agreement contains the entire
          ------------------------------                                     
security agreement and agency agreement, with respect to the Collateral, among
the Collateral Agent, the Secured Party and the Pledgor (other than the
Primestar Pledge and Security Agreement, to the 

                                       10
<PAGE>
 
extent applicable). If any of the provisions of this Agreement shall be held
invalid or unenforceable, this Agreement shall be construed as if not containing
such provisions, and the rights and obligations of the parties hereto shall be
construed and enforced accordingly.

     23.  Choice of Law; Submission to Jurisdiction. This Agreement shall be
          -----------------------------------------                         
construed in accordance with and governed by the internal laws of the State of
New York without giving effect to any conflicts of laws principles, and terms
used herein, except as otherwise (by reference or otherwise) defined herein
shall have the meanings given to them in the New York Uniform Commercial Code.
Each party hereto irrevocably submits to the jurisdiction of any New York State
court sitting in the Borough of Manhattan or any Federal court sitting in the
Borough of Manhattan in respect of any suit, action or proceeding arising out of
or relating to this Agreement and the transactions pursuant hereto and in
connection herewith, and irrevocably agrees that all claims in respect of any
such suit, action or proceeding shall be heard and determined in any such court.
Each party irrevocably waives any objection which it may now or hereafter have
to the laying of the venue of such suit, action or proceeding brought in any
such court and any claim that any such suit, action or proceeding brought in any
such court has been brought in an inconvenient forum.

     24.  Amendments, Etc.  No amendment or waiver of any provision of this
          ---------------                                                  
Agreement, nor consent to any departure by the Pledgor or the Collateral Agent
here from, shall be effective unless the same shall have been effected in
accordance with Section 15 of the SAR Agreement.

     25.  Notice. All notices, requests, demands, claims, and other
          ------                                                   
communications hereunder will be in writing.  Any notice, request, demand,
claim, or other communication hereunder shall be deemed duly given to the
intended recipient (i) upon telephonic confirmation of facsimile, (ii) when sent
by overnight delivery or (iii) seventy-two hours after deposit in the United
States mail when mailed by first class mail, postage prepaid, to the intended
recipient at the address or telecopier number, as applicable, for such recipient
set forth on the signature page hereof.  Notices, requests, demands, claims and
other communications may be sent by any other means (including personal
delivery, expedited courier, messenger service, or electronic mail), but no such
notice, request, demand, claim, or other communication shall be deemed to have
been duly given unless and until it actually is received by the intended
recipient.  Any party may change the address to which notices, requests,
demands, claims, and other communications hereunder are to be delivered by
giving the other party notice in the manner herein set forth, but no such notice
shall be deemed given until actually received.

     26.  Execution in Counterparts.  This Agreement may be executed in
          -------------------------                                    
counterparts, each of which when so executed shall be deemed to be an original
and all of which when taken together shall constitute one and the same
agreement.

     27.  Authorization to Further Pledge.  Notwithstanding any other provision
          -------------------------------                                      
herein, Pledgor consents to the creation of a lien on the Primestar Pledged
Rights pursuant to the Primestar Pledge and Security Agreement.  In order to
perfect the grant by Primestar under the 

                                       11
<PAGE>
 
Primestar Pledge and Security Agreement of a pledge of and security interest in
Primestar's Pledged Rights, the Secured Party hereby directs and authorizes the
Collateral Agent to pay and deliver to the Primestar PSA Collateral Agent
pursuant to the Primestar Pledge and Security Agreement, on behalf of the
Secured Party, any and all property and amounts, whether in cash or in kind, to
which the Secured Party may at any time, and from time to time, be entitled
hereunder. The Collateral Agent shall not have any liability whatsoever to
Pledgor or the Secured Party for any action by the Primestar PSA Collateral
Agent with respect to any property or amount paid or delivered to the Primestar
PSA Collateral Agent by the Collateral Agent pursuant to this Section 27. The
direction and authorization made herein is for the benefit of the Secured
Parties under the Primestar Pledge and Security Agreement and shall be
irrevocable prior to the Termination Date, whereupon it shall automatically
terminate.

                                       12
<PAGE>
 
          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed and delivered as of the day and year first above written.

                           TCI SATELLITE ENTERTAINMENT, INC.


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

                           Notice Address:  8085 South Chester, Suite 300
                                            Englewood, Colorado 80112
                                            Telephone No.:  (303) 712-4600
                                            Telecopy No.:  (303) 712-4977
                                            Attention:  Chief Financial Officer

                           with a copy to:  Baker & Botts, L.L.P.
                                            599 Lexington Avenue
                                            New York, NY 10022
                                            Telephone No. (212) 705-5000
                                            Telecopy No.:  (212) 705-5125
                           Attention: Elizabeth M. Markowski, Esq.


                           THE BANK OF NEW YORK,   as Collateral Agent


                           By:
                              ----------------------------------------------
                              Name:      Walter N. Gitlin
                              Title:     Vice President

                           Notice Address:  101 Barclay Street, Floor 21 West
                                            New York, New York 10286
                                            Telephone No.: (212) 815-5375
                                            Telecopy No.: (212) 815-5915
                                            Attention: Corporate Trust/
                                                       Trust Administration

                                       13
<PAGE>
 
                           PRIMESTAR, INC.


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

                           Notice Address:  8085 South Chester, Suite 300
                                            Englewood, Colorado 80112
                                            Telephone: (303) 712-4600
                                            Telecopy: (303) 712-4977
                                            Attention: Chief Financial Officer

                           with a copy to:  Baker & Botts, L.L.P.
                                            599 Lexington Avenue
                                            New York, New York 10022
                                            Telephone: (212) 705-5000
                                            Telecopy: (212) 705-5125
                                            Attention: Marc A. Leaf, Esq.

                                       14