<PAGE>
 
EXHIBIT 10.31

SATELITES MEXICANOS, S.A. DE C.V.
                                                          AGREEMENT NUMBER 095-1

INTERNATIONAL LEASE OF SATELLITE CAPACITY AGREEMENT OF THE MEXICAN SATELLITE
SYSTEM, EXECUTED BY AND BETWEEN SATELITES MEXICANOS, S.A. DE C.V., HEREINAFTER
REFERRED TO AS "SATMEX", HEREIN REPRESENTED BY ENGINEER LAURO ANDRES GONZALEZ
MORENO AS ITS DIRECTOR GENERAL, AND TELESPAN, INC , HEREINAFTER REFERRED TO AS
THE "CUSTOMER", REPRESENTED BY CHARLES RANDY POOLE, ITS LEGAL REPRESENTATIVE, IN
ACCORDANCE WITH THE FOLLOWING RECITALS AND CLAUSES:

RECITALS

1.   "SATMEX" STATES:

 .1   That it is a corporation incorporated under Mexican Law as recorded in
     Public Instrument number 51,371 dated June 26, 1997 executed before Lic.
     Miguel Alessio Robles, Notary Public number 19 of Mexico City, and recorded
     in the Public Registry of Property and Commerce under file number 226,109;
     it's primary corporate purpose is the installation, operation, control and
     exploitation of the Mexican Satellite System, via the occupancy and
     exploitation of geostationary orbital positions and satellite orbits
     assigned to the country, with their respective frequency bands and rights
     to transmit and receive signals in the terms of the Federal
     Telecommunications Law and the Communications Via Satellite Regulations.

 .1   That pursuant to articles 11, section III, 29, second paragraph and
     transitory fourth of the Federal Telecommunications Law and 7 of the
     Communications Via Satellite Regulations, through concessions dated October
     23, 1997 granted by the Minister of the Ministry of Communications and
     Transportation a concession was granted to Satelites Mexicanos, S.A. de
     C.V. to occupy geostationary orbital positions 109.2 degrees, 113.0 degrees
     and 116.8 degrees longitude west for the exclusive exploitation of "C" and
     "Ku" frequency bands and the rights to transmit and receive signals.

 .1   That Engineer Lauro Andres Gonzalez Moreno, as the Director General, is
     sufficiently qualified to execute this agreement, as evidenced by the
     Transcript of Public Instrument No. 19258 dated November 26, 1997, granted
     before Notary Public No. 102, of Mexico City, Lic. Jose Maria Morera
     Gonzalez.

 .1   That pursuant to Article 2 section VIII of the Regulations of
     Communications Via Satellite, it has the status of a satellite operator,
     which is defined as the person who, by a concession or assignment to occupy
     geostationary positions or satellite orbits assigned to the country, with
     their respective associated frequency bands, operates and exploits a
     satellite system allowing it only to provide its satellite capacity to
     third parties.

 .1   That it satisfies the technical and economic conditions to undertake in
     order to provide the service, subject matter of this agreement.

 .1   That its Federal Taxpayers Registration number is SME 970626 MK5.

 .1   That to exercise and comply with its rights and obligations hereunder, it
     shows its domicile as Blvd. M. Avila Camacho 40, 23rd floor, Colonia Lomas
     de Chapultepec, 11000, Mexico, D.F.

II   "THE CUSTOMER" STATES:

     II.1  That it is a corporation duly incorporated under the laws of the
state of Texas, U.S.A. as shown by  its Corporate Charter 01481013 dated
February 26, 1998 granted by the Secretary of the
<PAGE>
 
     *  CONFIDENTIAL PORTIONS HAVE BEEN OMITTED AND FILED SEPARATELY WITH THE
COMMISSION.
 
 
     State of Texas Alberto R.  Gonzales and duly certified with certificate
number N 147451 dated March 9, 1998 acting as Notary Public for the State of
Texas, Kathleen Keller and translated into Spanish by an authorized translator
designated by the Superior Court of Justice of the Federal District.

II.2   That Charles Randy Poole as its legal representative has sufficient
       faculty to execute this agreement, as evidenced by a Unanimous Board of
       Directors Resolution of Telespan, Inc. dated April 21, 1998 granted
       before Notary Public Rubby E. Santiago of the State of Texas and
       translated into Spanish by an authorized translator designated by the
       Superior Court of Justice of the Federal District. .
 
II.3   That it presents a certified copy of the documents mentioned in the
       preceding recital to allow "SATMEX" to verify their authenticity.

II.4   That it will timely notify "SATMEX" in writing of any modifications of
       its corporate name and/or of the power of attorney granted to its legal
       representative.

II.5   That it satisfies the applicable laws of the countries of within the
       coverage of Solidaridad 2 for Region 2 in which it will operated the
       service and has obtained from the respective Regulatory Entities the
       authorization(s) required to install, operate or exploit the transmitting
       and/or receiving earth station(s).

II.6   That it accepts the General Conditions for Provision of Signal Conduction
       via Satellite through the Mexican Satellite System issued by "SATMEX"
       (Addendum 1) as well as the Technical Addendum (Addendum II), which duly
       signed by the parties, are attached hereto and form an integral part
       hereof.

II.7   That it is familiar with the established legal framework both on the
       national and international levels to which the provision of services,
       subject hereof, are subject, and acknowledges to use said services and
       abide by said legal framework, and undertakes to use the services
       provided to it by "SATMEX" within the established legal framework in
       order to satisfy its communication requirements.

II.8   That it desires to contract the rights and obligations hereunder in the
       terms and conditions of the Clauses and Addenda of this agreement.

II.9   For the purposes of this agreement, it shows its domicile 12500 Network
       Blvd., Suite 407, San Antonio, Texas USA.

Having stated the above, the parties agree to execute this agreement and comply
with the following.

CLAUSES

                  FIRST.      "SATMEX" agrees to provide THE CUSTOMER with the
* CONFIDENTIAL            lease of satellite capacity by assigning the space
PORTIONS HAVE             segment on C Band Transponders *, in accordance with
BEEN OMITTED              the terms, conditions, technical, legal and rate
AND FILED                 specifications contained in this agreement and its
SEPARATELY                Addenda..
WITH THE
COMMISSION        SECOND.     "SATMEX" shall assign "THE CUSTOMER" the satellite
                          access frequencies and their respective operating
                          parameters based on the link budgets presented by "THE
                          CUSTOMER" to "SATMEX" for each receiving and/or
                          transmitting carrier that will accessed by its earth
                          stations forming its network.

<PAGE>
 
     "SATMEX" may modify the frequencies assigned to THE CUSTOMER, for justified
     reasons or optimization of space segment on the satellite, by written
     notice to "THE CUSTOMER" "THE CUSTOMER" agrees to make any changes within
     an agreed time frame thereby freeing up the prior frequencies.

          The satellite, band, coverage region, transponder, polarization, hook-
          up points, satellite frequencies, operation parameters, location of
          the earth stations, and antenna diameters are described in the Exhibit
          II of this agreement.  The Exhibit II will be updated when "THE
          CUSTOMER" requests modifications or expansion of the contracted
          service from "SATMEX", which must first be signed by both parties.

THIRD.    "THE CUSTOMER" agrees to notify "SATMEX" in writing any changes and/or
          modification of the names, titles, addresses, telephone number(s) and
          fax number(s) of the technician(s) responsible for its satellite
          network within five (5) days after such change and/or modification.

FOURTH    "SATMEX" shall deliver to "THE CUSTOMER"  in writing upon execution of
          this agreement the frequencies and operating parameters.

FIFTH     "THE CUSTOMER" will access and occupy the space segment contracted
          with "SATMEX", with its own earth stations or a third party stations
          that are part of this network and agrees  to use it exclusively to
          establish the public telecommunication network described in Addendum
          II.

SIXTH     The earth stations through which the services are to be provided must
          satisfy the specifications and technical characteristics established
          by "SATMEX" to operate with the Mexican satellite system having
          fulfilled recommendation 580-2 of the CCIR (29-25 log) and operate
          with frequency synthesizers and fractional ones.  The above is
          described in the technical memory of the network delivered by "THE
          CUSTOMER" to "SATMEX"

SEVENTH   For billing purposes, this agreement shall be in effect three (3) days
          after the execution of the agreement even if "THE CUSTOMER" does not
          have the necessary equipment to utilize the space segment.

EIGHTH.   "SATMEX" will send the monthly billing for the contracted service to
          the domicile shown by "THE CUSTOMER" within the first five (5)
          business days of each month, which will be in advance.  Billing will
          be calculated by applying the corresponding tariff for the type of
          service.

          If "THE CUSTOMER" does not timely receive the invoice at its domicile,
          it shall notify "SATMEX's" collection department in order to obtain
          the data it needs to timely pay the bill.  However, said situation
          does not release "THE CUSTOMER" of its payment obligation.

NINTH.    If "THE CUSTOMER" objects to any bill issued by "SATMEX", it shall
          send a request for verification and/or adjustment in writing, stating
          the reasons and causes for its objection, no later than within five
          (5) working days following the date of receipt thereof. If its
          objection is found to be correct, "SATMEX" will proceed to correct its
          bill, extending the payment due date for the equal number of days that
          elapsed between the original issued date and the corrected date.

          In order to correct the said bill as soon as possible, "THE CUSTOMER"
          agrees to provide all the necessary help to "SATMEX".
<PAGE>
 
                  * CONFIDENTIAL PORTIONS HAVE BEEN OMITTED AND FILED SEPARATELY
                  WITH THE COMMISSION.

        TENTH.    "THE CUSTOMER" agrees to provide a bond to "SATMEX" to
                  guarantee payment for the service for * that is equal to three
                  (3) times the monthly invoice. Said bond shall be issued by a
*                 duly authorized Mexican institution with "SATMEX" as loss
CONFIDENTIAL      payee.
PORTIONS
HAVE BEEN         "THE CUSTOMER" agrees to deliver the said guarantee, within
OMITTED AND       five (5) business days of execution of this agreement.
FILED
SEPARATELY        The bond must contain the following written conditions by the
WITH THE          institution providing the bond.
COMMISSION.
                  -That the bond be granted in the terms of this agreement.

                  -That in the event Addendum II is modified, "THE CUSTOMER"
                  shall make any adjustments necessary regarding the bond ,
                  within three (3) business days of any modification(s).

                  -That the bond will be in full force until "SATMEX" authorizes
                  in writing its cancellation.

                  -That it expressly submits to the jurisdiction and competency
                  of the Federal Courts of Mexico City, resigning to the forum
                  that would correspond due to its present or future domicile or
                  to other causes.

                  -That it expressly submits to the execution procedure foreseen
                  in Articles, 95bis and 118 of the "Federal Law of Bond
                  Institutions".

        ELEVENTH. "THE CUSTOMER" agrees to pay "SATMEX", in advance, for the
                  service tariff number *
* CONFIDENTIAL
PORTIONS HAVE     "THE CUSTOMER" agrees to pay by the fifteenth (15) day of each
BEEN OMITTED      month. If "THE CUSTOMER" fails to make two (2) consecutive
AND FILED         monthly payments, the service will be suspended. In order to
SEPARATELY WITH   reactivate "THE CUSTOMER" must pay all outstanding invoices,
THE COMMISSION    late payment fees and reconnections charges.

                  When "THE CUSTOMER" fails to pay two (2) or more monthly
                  payments, "SATMEX" may assign the capacity to another party.

        TWELFTH.  Late payment fees are calculated based on the rate resulting
                  from the sum of the Interbank Rate "TIE" issued by Banco of
                  Mexico, plus fifty percent (50%), in proportion to the number
                  of days of delay, divided between twelve (12) months on unpaid
                  balances of the monthly amounts owed.

                  Said fees shall apply from the day following payment due date
                  up to the day payment is received by "SATMEX".

        THIRTEENTH.  "SATMEX" shall only be responsible, for purposes of
                  compensation, for service interruptions for space segment or
                  of its own equipment, except for causes indicated in Paragraph
                  TWENTY.

                  In the event of a service interruption, "THE CUSTOMER" shall
                  immediately notify the "SATMEX" Satellite Control Center so
                  that it can determine the cause, correct the failure and
                  reestablish service; it shall also give written notice to
                  "SATMEX" so that, if applicable, and on the basis of the
                  technical report of the Control Center, the respective
                  compensation can be made as established in Addendum I.


<PAGE>
 
          "SATMEX" may interrupt the service whenever necessary to provide
          maintenance to its installation or equipment, among others, in
          coordination with "THE CUSTOMER" with no compensation due.  In any
          event, "SATMEX" will attempt to make the least interruptions in order
          to cause the least damage possible to "THE CUSTOMER".

          "SATMEX" will not be required to pay compensation for interruptions in
          the service derived from the operation of earth stations not
          authorized or technically approved and that cause interference.

FOURTEENTH. The effective term of this agreement shall be for three (3) years
          from the date of execution of this agreement.

FIFTEENTH.   "SATMEX" may at any time terminate the present agreement, without
          liability, for justified causes or reasons duly justified and proven,
          notifying "THE CUSTOMER" thirty (30) business days in advance.

          "THE CUSTOMER" may cancel portion of its satellite capacity or
          terminate this agreement, by notifying "SATMEX" in writing ninety (90)
          business days in advance

          In the event "THE CUSTOMER" cancels a portion of its satellite
          capacity or terminates this agreement before the term has expired as
          stated in Paragraph Fourteen, "THE CUSTOMER" shall pay "SATMEX" a one-
          time payment before the date requested by "THE CUSTOMER" an amount
          equal to the difference between the already paid and the tariff
          corresponding to one year agreements for each month in which the
          service was provided; in addition, at the same time "THE CUSTOMER"
          shall pay an amount whichever is greater:

          a) Twenty percent (20%) of the total payments unpaid from the date of
          termination of this agreement up to the end of the original agreed
          term.  In the event the notification is given during the last third of
          the original agreed term, the percentage shall be reduced to 15%, or

          b) The monthly tariff applicable to one year agreements, for each
          month remaining to conclude the original agreed term not exceeding
          twelve (12) months.
 
          In the event of partial cancellation the above mentioned payment shall
          apply only to the capacity affected.
 
          The termination date must be referenced as a calendar month (last day
          of month).

          The premature cancellation or termination of a service does not
          release "THE CUSTOMER"  from its obligation to pay outstanding amounts
          or late payment fees.

          "SATMEX" reserves the right to assign to another party the satellite
          capacity released by premature termination the day following the
          termination or cancellation date.

SIXTEENTH "SATMEX" may terminate this agreement for any of the following causes:

          I. If "THE CUSTOMER" assigns this agreement to a third party without
          previous consent in writing from "SATMEX".

          II. If "THE CUSTOMER" fails to pay two (2) consecutive monthly
          invoices or three (3) service interruptions during a one (1) year
          period.

          III. If "THE CUSTOMER" does not comply to the satellite access
          parameters indicated by SATMEX.
<PAGE>
 
          IV. If "THE CUSTOMER" does not deliver  in time and form the guarantee
          stated in Paragraph Ten.

          V. If "THE CUSTOMER" becomes the subject of bankruptcy, insolvency,
          reorganization or liquidation proceeding or finds itself under any of
          the conditions found in Article 2 of the Bankruptcy and Reorganization
          Law.

          VI. If "THE CUSTOMER" does not accept any relocation that "SATMEX" may
          assign on its satellites.

          VII. In general if "THE CUSTOMER" does not fulfill any of its
          obligations of this agreements as well as its Addenda.

SEVENTEENTH. If "SATMEX" considers that "THE CUSTOMER" has incurred in any of
          the causes of termination mentioned in the previous paragraph,
          `SATMEX" shall notify `THE CUSTOMER" in writing. "THE CUSTOMER" shall
          have fifteen (15) business days to respond. If "THE CUSTOMER" does not
          respond or if after "SATMEX" has reviewed "THE CUSTOMER's" response
          and "SATMEX" believes "THE CUSTOMER's" response is not satisfactory,
          "SATMEX" shall issue its resolution.

          In the event that "SATMEX" terminates this agreement, "THE CUSTOMER"
          agrees to make the payment referred to in Paragraph FIFTEEN.
 
EIGHTEENTH.  "SATMEX" shall have the option of applying a conventional penalty
          in addition to the mentioned in Paragraph Fifteen in the event "THE
          CUSTOMER" does not fulfill any of its responsibilities under this
          agreement which shall not exceed 10% of the total monthly payment or
          request that "THE CUSTOMER" because of its nonfulfillment payment for
          damages resulted to "SATMEX".

NINETEENTH.  In the event the parties do not agree, the representative elected
          by "SATMEX" shall notify in writing "THE CUSTOMER's" representative
          its objections immediately following detection so that both parties
          may reach an agreement to resolve the dispute.

          In the event the parties do not reach an agreement within ten (10)
          calendar days, the parties may request the intervention of the legal
          representatives of each party to reach an definite agreement regarding
          the nonfulfillment or disagreement.  In the event the legal
          representatives do not reach an agreement, the parties shall proceed
          to the established in Paragraph 23.

TWENTIETH.  "SATMEX" shall not be responsible for specific but not unlimited
          damages suffered by "THE CUSTOMER" or by third parties because of a
          delay in delivery of the service, deficient operation that could occur
          of the space segment as well as interruptions of service of the space
          segment or equipment due to fortuitous events or force majeure.

TWENTY-FIRST.  The parties agree to conserve all information and documentation
          exchanged by the parties as strictly confidential except for (i) if
          requested by the legal or administrative authorities or (ii) if such
          information is considered to be public knowledge.

          The parties may only utilize the confidential information only through
          previous written consent from the other party.
 
TWENTY-SECOND.  This agreement only covers the service provided by "SATMEX".
          "THE CUSTOMER" agrees to obtain authorization or a license from the
          proper authorities wherever the earth station(s) are located.
<PAGE>
 
TWENTY THIRD.  In the event of controversy regarding the fulfillment, contents,
          interpretation and scope of this agreement as well as anything not
          specifically stated herein, the parties agree to submit to the Federal
          District civil court and the jurisdiction and enforcement of the
          Federal Courts of Mexico City, waiving any other jurisdiction which
          may correspond to them for reason of their present or future domiciles
          or for any other reason whatsoever.

This agreement is executed in duplicate with each party receiving any original
in Mexico City on April 28, 1998.
               SATMEX                    CUSTOMER

               (SIGNATURE)               (SIGNATURE)

          ING. LAURO GONZALEZ MORENO     CHARLES RANDY POOLE
          PRESIDENT                      LEGAL REPRESENTATIVE
<PAGE>
 
                                                                      ADDENDUM I

SATELITES MEXICANOS, S.A. de C.V.

GENERAL CONDITIONS FOR THE PROVISION OF SATELLITE SIGNAL CONDUCTION  VIA THE
MEXICAN SATELLITE SYSTEM.

General Conditions for the Provision of Satellite Signal Conduction via Mexican
Satellite System, in which Satelites Mexicanos, S.A. de C.V. hereinafter SATMEX,
shall provide the service via the satellites for which it has been granted a
Concession by the Mexican Federal Government.

CHAPTER I
GENERAL PROVISIONS

1st ARTICLE  The purpose of this document is to set forth the general conditions
             which will govern the service provided by SATMEX.

2nd ARTICLE  The service which SATMEX will provide, consists of signal
             conduction via satellite, on C and KU Bands of the Mexican
             Satellite System, observing the provisions of its Concession
             Certificate, the Federal Telecommunications Law, the Communication
             Via Satellite Regulation, the Federal Law of Radio and Television
             and its Regulation, the UIT Consitution and Agreement, the
             International Telecommunications Regulation, International Treaties
             on the subject matter approved by the Senate of the Republic, and
             other administrative provisions on the subject matter.

3rd ARTICLE  The definitions of the technical terms used in the contracts,
             agreements or accords, shall be understood according to the
             definitions contained in the documents indicated in above 2nd
             Article, and any definitions issued by the Telecommunications
             Standardization, Radio Communications sectors and the Development
             of Telecommunications of UIT, as well as the Glossary of Terms used
             in Telecommunications published by the Ministry of Communications
             and Transportation through the Federal Telecommunications
             Commission and/or Telecommunications of Mexico.

4th ARTICLE  SATMEX will provide the service to establish a communication link
             in national or international territory for customers who so
             require. Customers have the responsibility to obtain the necessary
             concessions, permits or authorizations from the Federal Mexican
             Government or the authorities on the subject matter of each
             country.

5th ARTICLE  The earth stations and equipment to establish satellite links must
             be authorized by the Ministry of Communications and Transportation,
             must comply with Mexican Official Standards of technical
             specifications for services related to the conduction of signals
             between fixed points via the use of the Mexican Satellites. For the
             case of earth stations located abroad, Recommendation 580-2 of CCIR
             (29-25 log of 6) must be complied with.


CHAPTER II
PROVISION

6th ARTICLE  The services will be provided under the following conditions:
             Permanent - 24 hours a day, every day of the month or, less than 24
             hours by the hour or fraction thereof, at the same time, during
             every day of the month.

             Occasional.  For a determined time(s) of day and date(s) previously
             established for that occasion(s).

             For each of the foregoing, tariffs and regulations will be
             established.
<PAGE>
 
7th ARTICLE   Permanent service will be provided based on three categories
              according to continuity priority in the event of a contingency or
              partial or complete breakdown of the assigned satellite, as
              follows:

              FULLY PROTECTED SERVICE. The service which has a total backup on
              the same satellite or on another SATMEX satellite, except when the
              failure is caused by the actions or failure of the customer to
              fulfill SATMEX's conditions.

              NON-INTERRUPTED SERVICE. The service whose transponder has backup
              amplifiers and is not interrupted to give priority to a protected
              service, but does not have in the event of failure immediate
              protection on another transponder or satellite.

              INTERRUPTED SERVICE. The service subject to interruption as
              required at any time to give immediate protection to a protected
              service and to a non-interrupted service since these are
              priorities. In its normal operation the transponders has backup
              amplifiers.

              Each category of permanent service has a different tariff defined
              in the Tariff Manual and Technical Addendum (Addendum II of the
              corresponding agreement)

              When requesting the service, the customer shall indicate to SATMEX
              the band and the category of service it wishes to contract;
              however,, each service category is subject to the availability of
              the capacity of the space segment determined for each category at
              the time of contracting. SATMEX will indicate to future customers
              the availability of the space segment by category, tariffs and
              conditions for the provision of the service.

              The space segment for national security and social welfare has
              maximum priority over any service category in the event of a
              emergency.

              Occasional service will be provided subject to availability of the
              capacity to provide this type of service, for the dates and time
              requested. SATMEX will attend to the demand for the space segment
              for occasional services through the International Center for
              Reserve and Programming of Occasional Services (Booking) .

8th ARTICLE.  The space segment will be assigned based on information carriers
              and standard transmission speeds, by complete transponder or by
              fractions of bandwidth and/or transponder power, measured in
              megahertz (MHz) and watt decibels (dBw), respectively.

9th ARTICLE.  When contracting for the service, the client shall deliver a
              technical memory describing the network, its topology, the earth
              stations and equipment, access means to the satellite, the
              required capacity and link budget for each carrier, according to
              the format previously delivered by SATMEX. As well, SATMEX will
              publish a technical manual of its satellites, with the technical
              information, coverages, transponder parameters, sites, etc.,
              required for customers to develop their network and calculate the
              antenna diameter and link requirements.

10th ARTICLE. SATMEX, based on the requested capacity and the technical
              information presented by the customer, shall assign the satellite,
              transponder for each carrier contracted for, the transmission and
              reception frequencies, polarization and operating parameters, such
              as modulation, forward error correction (FEC), bandwidth (MHz),
              and earth station power requirements (dBw).

              The frequency receivers of the customers earth station must be
              efficient and for kilohertz. The operation of equipment with
              adjustable frequencies via crystals or with tuning limitations is
              not recommended because this does not allow the relocation of
              service in the event of interference and can also result in
              greater consumption of the bandwidth chargeable to the customer.
<PAGE>
 
11th ARTICLE. The technicians responsible designated by the customer to operate
              its earth stations of its satellite network may not exceed the
              normal parameters for access to the satellite assigned to each
              carrier. The personnel of SATMEX Center for Primary of Alternate
              Satellite Control of SATMEX, on detecting excesses, will
              immediately coordinate with the persons responsible for the earth
              station or the network, to make the necessary corrections. If the
              customer does not make the required correction, the customer shall
              be subject to fines for the use of excessive bandwidth or power or
              for damages caused to other customers.

              The fines will be for an amount resulting from applying the
              highest rate for the affected bandwidth and/or power affected, in
              addition to, if applicable, any compensation which SATMEX must pay
              the affected customer or customers. Payment of fines does not
              imply authorization to continue operating the service outside of
              the assigned parameters for access to the satellite.

              If the customer finds it necessary to operate with a higher level
              of satellite power, it may request SATMEX to authorize (with link
              budgets, and if authorized apply any adjustments to their invoice.

              The customer will include in the technical memory of its satellite
              network for each one of the earth stations that access the
              satellite assigned to SATMEX, the domicile(s), responsible
              technicians, telephone number(s) and facsimile (fax).

              SATMEX, shall deliver to customer in writing upon execution of the
              agreement, the access frequencies to the satellite and its
              operation parameters.

12th ARTICLE. Prior to accessing the satellite, customer shall coordinate with
              the Primary or Alternate Control Center the required technical
              tests of their earth stations consistently with the procedure and
              protocol established by SATMEX.

              SATMEX will grant its customers a maximum period of three (3)
              calendar days, at no cost, starting from the date on which they
              are notified of the assignment of the space segment contracted
              for, with the frequency and operating parameters, to allow them to
              conduct the tests of their earth station(s) and adjustments, in
              coordination with the Primary or Alternate Control Center.

              At the conclusion of this period, irregardless of whether the
              tests have been conducted, it will be understood that the service
              has been made available to the customer and the billing period
              will commence.

13th ARTICLE. The earth stations that do not satisfy the isolation, radiation
              pattern tests or any other parameters that affect or can affect
              other signals or satellites will not be authorized to operate with
              the satellites until corrected without any liability for SATMEX.

              As well, if an already approved earth station during its operation
produces interference to other signals will suspend its access until corrected.
In this case the customer must give the Primary or Alternate Control Center
assistance to eliminate such interference.

              In the event the responsible party for the earth station(s) does
not fulfill the indications of the Primary or Alternate Control Center to
correct or deactivate the earth station producing the interference, the
customers shall pay SATMEX a fine in an amount equal to 1% of the monthly tariff
for each hour or portion thereof of delay.

              In the event of earth stations that access a satellite for
occasional service, these earth stations must always coordinate testing and
power adjustments at least fifteen (15) minutes before the 
<PAGE>
 
hour indicated for the event. If this testing is not done, the Primary or
Alternate Control Center shall not allow access to the earth station.

     The customer agrees to oversee the operating state of the earth stations
and that these do not produce interferences to its own signals, other customer's
signals o to other satellites.

ARTICLE 14.   When a customer is affected in its signals by an unknown or
              undetermined interference and that cannot be corrected
              immediately, the customer shall have the option of being relocated
              immediately to a free space to continue its communications.

              This should be immediately reported to the monitoring area of the
Primary or Alternate Control Center so that they can coordinate with the
assignment area, and support any relocation activities.  In this event, SATMEX
shall give the customer new frequencies and operating parameters either
temporary or definite.

              Expenses implied by any relocation of frequencies shall be the
customer's responsibility.

ARTICLE 15.   Any modification in service or relocation must be requested thirty
              (30) days in advance and the corresponding technical memory and
              link budget shall be included for the modified carriers or new
              sites.

              The customer must not make any changes without previous
              coordination with SATMEX.

CHAPTER III.
AGREEMENTS

ARTICLE 16.   To contract the service the customers must have a public network
              concession or license as stated in articles 24 and 31 of the
              Federal Telecommunications Law and in accordance with the
              established in the Regulations for Satellite Communications. Any
              concession or license shall be the customer's responsibility. A
              copy of this document must be presented to SATMEX so that it
              becomes an integral part of the agreement as an Addendum.

ARTICLE 17.   Terms of the agreements will be specified in each document
              executed by the customers in accordance with the following:

              I.   The minimum term shall be determined by the type of service
                   requested by the customer and shown in the corresponding
                   tariff.

              II.  The agreement for permanent services offered by SATMEX shall
                   have a 1 year minimum and three (3), five (5) and ten (10)
                   years for long term agreements. The agreements can be
                   terminated in the event of satellite failure and as long as
                   there is no replacement capacity.

              For periods shorter that one (1) year, the rule indicated in the
              respective tariff will apply.

              III  To calculate the term of the Permanent Service agreement, it
                   will be understood that it begins as of the day following the
                   date on which the agreement is signed.

              IV   Occasional services must be contracted at least six (6) hours
                   in advance on business days, except in the cases, indicated
                   in paragraph VI of this article.

              V    Customers may cancel any occasional service contracted, or
                   they may expand the time requested. In both cases, they will
                   be subject to the minimum payment or the surcharge indicated
                   by corresponding tariff.

              VI   Urgent occasional services will be provided if contracted
                   with less advance notice that indicated in paragraph IV,
                   provided that it is technically possible to supply 
<PAGE>
 
                   them, in which case a surcharge will apply of up to fifty
                   percent (50%) of the respective tariff.

              In this case, the mere receipt of written communication from the
              customer through its legal representative or technical
              representative requesting the service will suffice to confirm the
              provision of the service.

              If SATMEX is technically unable to provide the requested service,
              it will notify the customer by the most convenient method.

18th ARTICLE. The rights and obligations under the agreements may be assigned to
              third parties by the customer with the prior express written
              consent of SATMEX. For this, the new interested party must
              subscribe and execute the relevant agreement.

19th ARTICLE. Customers are required to give written notice to SATMEX at least
              thirty (30) business days in advance of any modification they are
              going to make of its corporate name, change of domicile, legal
              representative(s), telephone and facsimile (fax) number(s).


CHAPTER IV.
GUARANTEES

20th ARTICLE. SATMEX may, at its discretion, demand payment guarantees, which
              will be specified in form and amount of each agreement.

CHAPTER V.
BILLING.

21st ARTICLE. The amounts that result from applying the contracted service rate
              will be notified to customers monthly, indicating the amount,
              form, place and date of payment, by an official invoice which will
              be valid when it shows bank payment validation or SATMEX's stamp
              evidencing payment. The invoice, with and exhibit itemizing the
              charges applied, will be sent to the customer's domicile shown by
              customer in the agreement. Invoices issued to customers with a
              domicile in Mexican territory will be stated in domestic currency
              and will include the value added tax (IVA). Invoices to customers
              with domicile outside of Mexico will be stated in dollars, United
              States of America currency, excluding Mexican taxes.

22nd ARTICLE. The amount stated in the monthly invoice for services provided
              will be the result of applying the respective tariff to the class
              of service contracted, pursuant to the provisions of SATMEX
              Addendum II of the respective agreement.

              When the rate is stated in United States of America dollars, for
              its national currency billing, the exchange rate that is published
              by "Banco de Mexico' at the closure of the last working day of the
              prior month in which the service is provided shall apply.

23rd ARTICLE. When the magnitude of some of the concepts used to apply the
              tariffs reflect fraction higher that those established in the
              tariff, they will be converted to unit values, to the 10th or
              100th, rounding them out upward to the immediately higher number,
              as needed.

24th ARTICLE. As to the concepts used for applying the tariff that are in terms
              of time (hours or part of and hour), they will be considered in
              the form stated in the tariff applicable to the service
              contracted.

25th ARTICLE. Invoices for the supply of permanent services will cover periods
              of one calendar month, except when the service commences on a day
              other than the first day of the month, in 
<PAGE>
 
              which case the first invoice will cover the amount corresponding
              to the number of days still remaining in said month in which the
              service is provided.

26th ARTICLE. Public or private natural or corporate persons shall pay the
              amounts shown in their monthly invoice no later than the fifteenth
              (15) day of each month, at the places and times indicated by
              SATMEX and/or stated on the invoice.

27th ARTICLE. If the customer does not timely receive the invoice at its
              domicile in the first five (5) working days of each month, it
              shall notify SATMEX's collection department in order to obtain the
              data it needs to timely pay the bill. However, said situation does
              not release it of its payment obligation, particularly in the case
              of a monthly fixed charge. In every case, customer shall ask for
              its outstanding balance from SATMEX's collection office.


CHAPTER VI.
PAYMENTS.


28th ARTICLE. SATMEX will publish a manual containing the tariffs and general
              provisions authorized by the Ministry of Communications and
              Transportation which are to be applied to the various public
              satellite services, and will deliver a copy to the customer of the
              tariff for the service contracted.

29th ARTICLE. Customers will make their payments to SATMEX for satellite
              services provided at the banks authorized by SATMEX or directly to
              SATMEX's cashier, within the following periods:

       I      Permanent services at a fixed monthly charge are to be paid by the
              fifteenth (15) day of each month that the service is provided.

       II     Occasional services are to be paid before provided.

       III    Foreign-resident customers are to pay their invoices during the
              period indicated in the first paragraph of this article and in the
              same currency in which the invoice is presented.

       Customers may arrange with SATMEX for other forms for making monthly
       payments, such as an electronic bank transfer.

30th ARTICLE. If customer does not promptly pay its invoices, SATMEX will notify
              the customer its outstanding invoices and apply late payment fees
              beginning the next day following due date.

31st ARTICLE. SATMEX will at all times have the right to suspend the service in
              the event of a failure to pay two months' bills. In the event of a
              suspension, customer will have ten (10) business days to pay its
              outstanding invoices; in order to reactivate the service, the
              customer must first pay its outstanding amount, reconnection
              charges and late payment fees.


CHAPTER VII.
COMPENSATIONS.

32nd ARTICLE. For purposes of compensation, SATMEX will be liable only for
              service interruptions for space segment, except for acts of God or
              force majeure.

              SATMEX shall not have any responsibility for harm and damages
              caused by interruptions of the service to the customer or third
              parties.
<PAGE>
 
33rd ARTICLE  SATMEX will not be required to pay compensation for interruptions
              of service caused by the operation of earth station(s), owned by
              customer, for lack of authorization or not technically approved
              that causes interference, as well as for the partial or total
              suspension of a interruptible service for giving immediate
              protection to a fully protected or non interrupted service which
              has priority.

34th ARTICLE. In the event of an interruption in the provision of the service,
              the customer shall immediately notify the SATMEX Control Center in
              order to determine the cause, correct the failure and reestablish
              the service; customer also agrees to give written notice to SATMEX
              so that it may make the respective compensation if applicable
              based on the Control Center's technical report.

              The compensations will be considered from the date in which SATMEX
              Control Center issues the confirmation report of the causes that
              originated the interruption.

35th ARTICLE. Interruptions of the service provision imputable on SATMEX will be
              compensated as follows:

              I.      In case of permanent services supplied during the 24 hours
                   of the day, only interruptions of three (3) continual hours
                   will be compensated. The compensation will be equal to one-
                   eighth of the billing for one (1) day. Part of an hour will
                   be computed as a full hour.

              I.      Occasional or periodic services provided for periods of
                   hours, half-hours or minutes: for each minute of
                   interruption, the compensation will be equal to the rate per
                   minute, applied to the number of minutes during which the
                   interruption persisted.

              I.      SATMEX will not consider requests for compensation when
                   the interruption results from negligence of the customer or a
                   breakdown of its apparatus and equipment, the maintenance and
                   operation whereof correspond to the customer.

              I.      Compensation, when applicable, will be credited to the
                   customer in the invoice payable of the second and third month
                   subsequent to the month in which the interruption occurred.

              I.      As to occasional services, if the customer requests a
                   suspension of already initiated service prior to the
                   conclusion of the contracted schedule, customer will not be
                   entitled to any compensation.

              I.      Refunds will proceed only when it is not possible to apply
                   the compensation to other periods or services of the
                   customer.


CHAPTER VIII.
PREMATURE TERMINATION.


36th ARTICLE. SATMEX may at any time terminate the agreement with no liability
              on its part, for justified causes or for reasons duly motivated
              and justified giving notice to customer thirty (30) business days
              in advance.
<PAGE>
 
37th ARTICLE. Customer may terminate the respective agreement, notifying SATMEX
              in writing at least thirty (30) business days in advance for 
              short-term services, and ninety (90) business days in advance for
              long-term services.

              In the case of permanent services, if customer terminates the
              service prematurely - that is, before the conclusion of the agreed
              term, it shall pay, except where termination results from a
              failure of the satellite and/or replacement capacity is not
              available, the following penalties:

              The amount resulting of the difference between the amount paid and
              the monthly rate corresponding to one (1) year agreements for each
              month that the service has been provided; and in addition the
              customer shall pay in the same date the highest amount that
              results from:

              a) Twenty percent (20%) of the total payments unpaid from the date
              of the termination until the end of the originally agreed term of
              the respective agreement. If the termination occurs during the
              second third of the term of the agreement, the percentage will be
              reduced to fifteen percent (15%).

              b) The monthly tariff corresponding to one year agreements for
              each month until the conclusion of the original period of the
              agreement, not to exceed twelve (12) months. Failure to give
              notice referred to in the first paragraph of this article will
              allow SATMEX to continue providing the service in the implied
              manner, and charge the accounts in full for the ensuing months
              until customer gives notice of renewal or termination, as the case
              may be.

              The cancellation or premature termination of a service does not
              release the customer from prior debts or late payment fees.

              SATMEX reserves the right to assign to other customers the
              released satellite capacity on the next day following the
              termination date.

38th ARTICLE. Agreements for occasional or periodic services may be terminated
              in advance when the customer timely gives the termination notice
              with the following periods:

              1.  If the service is canceled before ten (10) calendar days prior
              to the date of the event, no charge will apply.

              2.  If the service is canceled between ten (10) calendar days and
              forty-eight (48) hours prior to the event, a charge for the
              equivalent of sixty percent (60%) of the price of the requested
              service will be imposed.

              3.  If the service is canceled forty-eight (48) hours prior to the
              event, or the service is not used, one hundred percent (100%) of
              the price of the requested service will apply.


CHAPTER IX
CAUSES FOR TERMINATION


39th ARTICLE  SATMEX may terminate a service agreement in the following events:

              I.   If customer assigns in any way the rights and/or obligation
              derived of the corresponding agreement to third parties, without
              the previous written consent by SATMEX.
<PAGE>
 
              II.  If customer fails to pay two (2) consecutive bills for the
              service provided or three (3) suspensions of said bills in a one
              (1) year period.

              III. If customer does not comply with the satellite access
              parameters indicated by SATMEX.

              IV.  If customer does not provide the guarantee stated in article
              20.

              V.   If customer becomes the subject of bankruptcy, insolvency,
              reorganization or liquidation proceeding or finds itself under any
              of the conditions found in Article 2 of the Bankruptcy and
              Reorganization Law.

              VI.  If customer does not accept the relocation that SATMEX should
              assign.

              VII. In general, if customer fails to comply with any of the
              obligations under the respective agreement, or its addenda.

40th ARTICLE. If SATMEX has elements to prove that customer has incurred in any
              of the causes for termination, it will give written notice to
              customer to such effect within fifteen (15) business days to allow
              customer to assert its rights.



                          SATMEX                         THE CUSTOMER

                        (Signature)                       (Signature)

              ING. LAURO ANDRES GONZALEZ MORENO       CHARLES RANDY POOLE
              PRESIDENT                               PRESIDENT
<PAGE>
 
          *  CONFIDENTIAL PORTIONS HAVE BEEN OMITTED AND FILED SEPARATELY WITH
          THE COMMISSION.

                                  ADDENDUM II
                            INTERNATIONAL SERVICE OF
                        SIGNAL CONDUCTION VIA SATELLITE

                              GENERAL INFORMATION
 
<TABLE> 
<CAPTION> 

<S>            <C>                                  <C>                 <C>                     <C>  
Customer:      TELESPAN, INC.                       R.F.C.
Address:       12500 NETWORK BOULEVARD, SUITE 407
City:          SAN ANTONIO TEXAS USA                Zip Code:            78249
Contract No.   095-I            Date:               Term:                3 years
Legal Rep:     CHARLES RANDY POOLE
Telephone:     (210) 558 60 90                      Fax:         (210) 558 60 95
 
                        TECHNICAL INFORMATION OF ASSIGNED CAPACITY
 
Type of Network:  POINT TO POINT                 Bandwidth: *                                     *
Type:             PUBLIC                         Transponder Power                                CONFIDENTIAL
Satellite:        *               Band: C        Service Category: Uninterrupted                  PORTIONS
Orbital Position: 113 degrees 0"  Transponder: * Ranges:                                          HAVE BEEN
Region:           R1          Polarization: H/V  Connectivity: R1/R1                              OMITTED AND
     No. of Carriers    Freq.    Speed (Kbps)    Modulation    FEC    Access                      FILED
                                                                                                  SEPARATELY
                                                                                                  WITH THE
                                                                                                  COMMISSION
Teleport: SAN ANTONIO TEXAS


                                     TARIFF

Tariff No: 3
Term:   *                     Monthly Charge: * USD                                               * CONFIDENTIAL
Commencement Date: May 1, 1998      Termination Date: April 31, 2001                              PORTIONS HAVE
                                                                                                  BEEN OMITTED
Observations: Nominal bandwidth in accordance with applicable rules                               AND FILED
                                                                                                  SEPARATELY
                                                                                                  WITH THE
                                                                                                  COMMISSION.
Mexico, D.F.  April 28, 1998
</TABLE> 


          SATMEX                         THE CUSTOMER

          (Signature)                    (Signature)

     ING. LAURO ANDRES GONZALEZ MORENO      CHARLES RANDY POOLE
          PRESIDENT                           PRESIDENT