<PAGE>   1
                                                                   EXHIBIT 10.75

                              STS-95 USER CONTRACT
                                       (A)


         This STS-95 User Contract (A) ("Contract") is made this 20th day of
December, 1997, between SPACEHAB, Incorporated ("SHI"), a Washington state
corporation with its principal office located in Vienna, Virginia and Mitsubishi
Corporation, with its principal office located in Tokyo, Japan ("MC"), as
contractor to the National Space Development Agency of Japan ("NASDA",
collectively "BUYER").

         WHEREAS MC desires to procure SPACEHAB pressurized module services
("SPACEHAB" or "Module") and retain SHI to act as the carrier and interface
between the U.S. National Aeronautics and Space Administration's ("NASA") Space
Shuttle fleet and the experiments listed in Exhibit A aboard a SPACEHAB Module
Mission currently manifested as STS-95.

         WHEREAS SHI desires to supply to MC such services and to act as the
carrier and interface between the NASA Space Shuttle fleet and the experiments
listed in Exhibit A aboard a SPACEHAB Module Mission currently manifested as
STS-95 ("Mission"); and

         WHEREAS SHI must immediately begin to perform certain tasks associated
with the analytical and physical integration of the Exhibit A experiments into
the SPACEHAB Module in order to complete these tasks prior to the anticipated
launch date;

         WHEREAS, the parties desire to perform their respective obligations
necessary to fully achieve these desires pursuant to three sequential contracts
(A, B and C); and

         WHEREAS MC, NASDA, and SPACEHAB have mutually agreed to the Experiment
Chargeable Mass policy presented in the Exhibit B table.

         NOW THEREFORE, in consideration of the mutual covenants hereinafter set
forth, the parties agree as follows:

1.       STATEMENT OF WORK

         SHI will provide, at the times and locations set forth therein and
         pursuant to the terms and conditions of this Contract, the supplies and
         services described in the Statement of Work ("SOW") in Exhibit C (a)
         for the payloads listed in Exhibit A (both exhibits incorporated herein
         by reference) as follows: VFEU (chargeable mass 215 kg), BRIC
         (chargeable mass 40 kg), OCC (chargeable mass 15 kg),
         Oceaneering/SPACEHAB Refrigerator/Freezer (OSRF) (chargeable mass 45
         kg), and Camcorder/Microcam/StillCam (chargeable mass 10 kg). The OCC
         experiment support hardware includes the 3-Dimensional Microgravity
         Accelerometer (3-DMA) and the Japanese United States Thermal Sciences
         Acceleration Project (JUSTSAP) supplied by the University of Alabama -
         Huntsville, Consortium for Materials Development in Space. There is no
         charge to MC/NASDA for use of this hardware under this contract.

2.       PRICE AND TERMS OF PAYMENT
<PAGE>   2
         MC shall pay SHI a fixed price of 1997 US$880,000 at the time set forth
         below. Included in this price is the lease of the OSRF and the
         associated integration and operations services performed by Oceaneering
         Space Systems of Houston, Texas.

<TABLE>
<S>                       <C>           <C>
         -  97US$          880,000.00   upon execution of this Contract.
              Total       $880,000.00
</TABLE>

         The actual Chargeable Mass (reference Exhibit B) for each experiment in
         Exhibit A and its supporting flight hardware shall be determined by SHI
         using a calibrated scale at the time of installation of each experiment
         into the module. Any upward adjustment in the total measured Chargeable
         Mass flown on the mission from the Chargeable Mass referred to in
         Section 1 above shall result in an upward price adjustment for that
         experiment at the rate of $28,000/kg.

3.       PAYMENT TERMS AND CONDITIONS

         SHI shall send a Final Accounting/Billing to MC as promptly as possible
         after completion of the last service provided by SHI under this
         Contract. The Final Accounting/Billing will contain a final accounting
         under the Contract and address additional payment requirements, if any,
         from MC. If, as a result of final Accounting/Billing, an additional MC
         payment is required, such payment shall be due 60 days after the
         billing date of the Final Accounting/Billing.

4.       MISSION DELAYS

         In the event STS-95 is delayed, suspended, or postponed, there may be
         additional charges to MC as specified in the following circumstances:

         a.     Delay caused by NASA

                MC pays only additional service costs, if any, required/provided
                by NASA and/or SHI.

         b.     Delay caused by SHI

                MC pays only additional service costs, if any, required/provided
                by NASA.

         c.     Delay caused by MC or NASDA

                MC pays any additional NASA costs charged to SHI which may be
                required or caused by any delay, suspension or postponement of
                the launch in excess of the 72 hours allowable delay for which
                NASA does not charge. MC pays for any additional costs incurred
                by SHI for services provided by NASA and/or SHI.

5.       OPTIONAL SERVICES

         There are currently no optional services priced under this Contract.
         Prices for any optional services will be negotiated on an individual
         basis and will be in addition to the price as set forth in Section 2
         above.

6.       APPLICABILITY OF NASA/SHI SPACE SHUTTLE CONTRACTS
<PAGE>   3
         SHI and MC acknowledge that performance of the services described in
         this Contract and the SOW depends upon the Contract(s) governing NASA's
         manifesting and use of the Module for STS-95 ("NASA Contracts"). Any
         changes to these NASA/SHI Contract(s) that are imposed by NASA and
         which prevent SHI from providing the services described herein shall
         not constitute a breach of this Contract by either SHI or MC. In the
         event of such changes by NASA, SHI and MC agree to negotiate an
         equitable adjustment to this Contract that satisfies both parties as
         well as NASA's new requirements. If there are any conflicts between
         this Contract and the requirements of the NASA Contracts applicable to
         this Contract, the NASA Contracts terms and conditions shall take
         precedence.

7.       EXCHANGE OF DOCUMENTATION AND INFORMATION

         SHI and BUYER shall exchange all documents and information required for
         each party to fulfill its responsibilities under this Contract in
         accordance with the November 1997 SPACEHAB/NASDA/MC STS-95
         Confidentiality & Nondisclosure Contract.

8.       PERMITS AND LICENSES

         SHI shall obtain any permit or license that may be required to provide
         the services to be furnished under this Contract. MC will be
         responsible for obtaining any permit or license that may be required to
         perform an activity unique to the Exhibit A experiments that is not
         included in the foregoing, such as tests involving use of radioactive
         materials or particular requirements of MC's own government(s), or
         governmental authorities outside the United States.

9.       ALLOCATION OF CERTAIN RISKS AND LIMITATION OF LIABILITY

         a.     Insurance Coverage In Lieu of NASA FAR Supplement Cross-Waiver

                SHI agrees to purchase indemnification insurance covering
                participants who otherwise would have been covered by the cross
                waiver provisions set forth in the NASA FAR Supplement in the
                event MC or NASDA were materially damaged by one or more of such
                participants during the payload processing activities or STS
                Operations.

         b.     Risk of Patent Infringement

                (i)      SHI agrees to indemnify MC, its officers, employees and
                         agents against any United States Patent infringement
                         costs (including, but not limited to, any judgment
                         against MC by a court of competent jurisdiction,
                         reasonable administrative and litigation costs, and
                         settlement payments made as a result of an
                         administrative claim) incurred by MC which are
                         attributable to products, processes or articles of
                         manufacture used in the facilities and Services to be
                         furnished to MC by SHI hereunder.

                (ii)     MC agrees to indemnify SHI and NASA, their officers,
                         employees and agents against any United States Patent
                         infringement costs (including, but not limited to,
                         judgment against SHI by a court of competent
                         jurisdiction, reasonable administrative and litigation
                         costs, and settlement payments made as a result of an
                         administration claim) incurred by SHI and/or NASA which
                         are attributable to products, processes or articles of
                         manufacture used in Exhibit A experiments and any
                         supporting equipment and facilities brought to the SHI
                         SPPF by MC or MC's contractors or subcontractors and
                         any activity performed at SHI or NASA facilities 

<PAGE>   4
                         by MC or MC's contractors or subcontractors and any
                         activity performed at SHI or NASA facilities by MC or
                         MC's contractors or subcontractors.

         c.     Limitation of SHI and MC Liability

                Notwithstanding any other provisions herein, to the extent that
                a risk of damage is not dealt with expressly in this Contract,
                SHI's and MC's liability under this Contract, whether or not
                arising as a result of an alleged breach of this Contract, shall
                be limited to direct damages only and shall not include any loss
                of revenue, profits or other indirect or consequential damages.

10.      ASSISTANCE WITH THIRD PARTY CLAIMS

         In the event a third party claim is asserted against SHI or MC as a
         result of patent infringement, use of proprietary data, or damage,
         including claims of their respective contractors or subcontractors,
         arising from or in connection with the Services provided by SHI under
         this Contract, SHI and MC each agree to give prompt notice to the other
         of any such claim and agree to provide each other with any assistance
         practicable in the defense against such claim. If a claim asserted
         against one party is a claim under this Contract, the party who has
         agreed to indemnify shall have the right to intervene and defend, the
         right to control litigation of, and the right to determine the
         appropriateness of any settlement related to such claim.

11.      WARRANTIES

         SHI makes no warranties of any kind, express or implied, including any
         implied warranty of merchantability or fitness for a particular
         purpose.

12.      PUBLICITY RELATING TO CONTRACT

         In cases where one Party intends to use results obtained from this
         Contract or advertise his role in this Contract, it shall first request
         the other Party for its prior written approval, which shall not be
         unreasonably withheld.

13.      APPLICABLE LAW

         The Contract shall be governed by the laws of the State of Virginia.

14.      ARBITRATION/DISPUTES

         Disputes arising out of the interpretation or execution of this
         Contract which cannot be resolved by negotiation shall, at the request
         of either Party, (after giving 30 days notice to the other Party) be
         submitted to arbitration. The arbitration tribunal shall sit in
         Washington DC. Disputes shall be finally settled in accordance with the
         Rules of Conciliation and Arbitration of the International Chamber of
         Commerce by one or more arbitrators designated in conformity with those
         Rules. The decision to submit a dispute shall not excuse either party
         from the timely performance of its obligations hereunder which are not
         the subject matter of the dispute. Further, if the lack of resolution
         of the matter in dispute will adversely impact the timely completion of
         preparation for launch activities, MC and SHI will perform the matter
         in dispute in the manner determined by SHI, within the framework of
         this Contract and without prejudice to the final resolution of the
         matter in dispute.
<PAGE>   5
15.       TERMINATION OF SERVICES

         Both parties have the right to terminate this Contract pursuant to the
         following conditions only:

         a.     SHI may terminate this Contract:

                (i)   In the event NASDA delivers any payload described in the
                      SOW so late beyond the mutually agreed upon delivery date
                      that SHI, in its sole reasonable judgment, is unable to
                      process such payload in time to meet the launch schedule,
                      SHI will terminate this Contract and shall retain all
                      payments made by MC to the date of termination, and MC is
                      further liable for all costs incurred by SHI as a result
                      of such NASDA failure, or

                (ii)  In the event of a material breach by MC which MC fails to
                      cure within a reasonable time after written notice
                      received from SHI (or immediately upon a non-curable
                      breach), in which case SHI shall retain all payments made
                      to the date of the termination, and MC is further liable
                      for all costs incurred by SHI resulting from MC's breach
                      of the Contract or,

                (iii) As a result of any actions or inactions by NASA which
                      prevent the manifesting of the Exhibit A experiments on
                      STS-95, in which case SHI shall be entitled to all
                      payments hereunder received to the date of termination,
                      plus the Integration and Optional Services (if any) actual
                      costs incurred up to the time of termination, as well as
                      all termination charges which may be imposed by third
                      parties (such as NASA or SHI subcontractors).

         b.     MC may terminate this Contract:

                (i)   Without cause at any time before installation of the
                      Exhibit A experiments into the SHI module upon sufficient
                      written notification to SHI of such intent, in which case
                      MC shall be liable for and SHI shall retain all payments
                      hereunder received up to the date of termination, plus the
                      Integration and Optional Services (if any) actual costs
                      incurred up to the time of termination, as well as all
                      termination charges which may be imposed by third parties
                      (such as NASA or SHI subcontractors), or,

                (ii)    In the event of material breach by SHI which SHI fails
                        to cure in a reasonable time after written notice of
                        such material breach is received from MC, in which case
                        MC will be relieved from making any further payments to
                        SHI subsequent to the material breach hereof.

         c.     Termination In Special Cases:

                MC may terminate this Contract by giving written notice with
                immediate effect in any of the following events:

                (i)   If SHI becomes insolvent or if its financial position is
                      such that within the framework of its national law, legal
                      action leading towards bankruptcy may be taken against it
                      by its creditors;

                (ii)  If SHI resorts to fraudulent practices in connection with
                      the contract, especially by deceit concerning the nature,
                      quality or quantity of the supplies, and the methods or

<PAGE>   6
                      processes of manufacture employed or by the giving or
                      offering of gifts or remuneration for the purpose of
                      bribery to any person in the employ of NASDA or acting on
                      its behalf, irrespective of whether such bribes or
                      remuneration are made on the initiative of SHI or
                      otherwise.

16.      ASSIGNMENTS

         No party shall assign to another person or entity any part of its
         rights under this Agreement, including but not limited to rights for
         services related to scheduled launches, unless otherwise expressly
         agreed to by the other party in writing, or as may be required pursuant
         to law.

17.      NOTICES

         All notices, requests, demands, and other communication hereunder shall
         be in writing and shall be either (1) personally delivered, (2) sent by
         mail or reputable overnight delivery service, or (3) transmitted by
         facsimile machine as follows:

         To SHI:                    Ms. Nelda Wilbanks
                                    Contracts Administrator
                                    SPACEHAB, Inc.
                                    1595 Spring Hill Road, Suite 360
                                    Vienna, VA  22182 USA

         To MC:                     Mr. Kazushi Ochi
                                    Manager, Space Systems Unit
                                    Mitsubishi Corporation
                                    2-6-3 Marunouchi, Chiyoda-ku
                                    Tokyo, Japan 100-86

         The effective date of each notice, demand, request or other
         communication shall be deemed to be: (1) the date of receipt if
         delivered personally or by mail or overnight delivery service, or (2)
         the date of transmission if by facsimile. Either party may change its
         address or designee for purposes hereof by informing the other party in
         writing of such action and the effective date of such change.

18.      FORCE MAJEURE

         Neither party shall be liable for delays or breaches hereof resulting
         from events or acts beyond the control of such party, including but not
         limited to acts of God, strikes, lockouts, riots, acts of war,
         epidemics, governmental regulations, and natural disasters. Upon the
         occurrence of such event, the party whose performance is affected shall
         use reasonable efforts to notify the other party of the nature and
         extent of any such condition and negotiate its affects.

19.      COMPLETE CONTRACT

         This Contract constitutes the complete Contract and understanding with
         respect to the subject matter hereof between the parties.

         Mitsubishi Corporation                      SPACEHAB, Inc.

         By:________________________                 By:________________________
              K. Ochi, Manager                           Nelda Wilbanks
              Space Systems Unit                         Contracts Administrator
              Aerospace Division
<PAGE>   7
                                    EXHIBIT A
                                 EXPERIMENT LIST


1. NASDA'S VESTIBULAR FUNCTION EXPERIMENT UNIT (VFEU) - CHARGEABLE MASS 215 KG

2. NASDA'S BIOLOGICAL RESEARCH IN A CANISTER (BRIC) - CHARGEABLE MASS 40 KG 

3. NASDA'S ORGANIC CRYSTAL CHAMBER (OCC)* - CHARGEABLE MASS 15 KG 

4. OCEANEERING/SPACEHAB REFRIGERATOR/FREEZER - CHARGEABLE MASS 45 KG 

5. CAMCORDER/MICROCAM/STILLCAM - CHARGEABLE MASS 10 KG


* THE OCC EXPERIMENT SUPPORT HARDWARE INCLUDES THE 3-DIMENSIONAL MICROGRAVITY
ACCELEROMETER (3-DMA) AND THE JAPANESE UNITED STATES THERMAL SCIENCES
ACCELERATION PROJECT (JUSTSAP). HOWEVER, THERE IS NO "CHARGEABLE MASS" ALLOCATED
TO MC/NASDA FOR THE USE OF THIS HARDWARE, SUPPLIED BY THE UNIVERSITY OF ALABAMA
- HUNTSVILLE, CONSORTIUM FOR MATERIALS DEVELOPMENT IN SPACE.