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the weight of the Orbiter).  Braking is initiated around 130 knots or at midfield at 8 to 10 feet per second squared.  If rollout speed is greater than 140 knots at the point when only 5000 feet of runway remains, maximum braking is used.  This is applicable at transatlantic abort landing (TAL) sites with shorter runways.  The brakes are held constantly until velocity has been reduced to 40 knots in order to assure that any brake damage that may have occurred will not contribute to a wheel lockup, and to manage the total heat load put into the brakes to try to get maximum use capability if required for stopping or directional steering.

IV. PROGRAM ADVANTAGES OF LANDING AT KSC

The original Space Shuttle design called for routine landings at KSC in order to optimize turnaround time, to minimize cost per flight, and to provide an effective operation for both the Space Transportation System (STS) and the cargo elements.  These are still valid concerns.

Cargo elements located in the Orbiter payload bay are designed for the space environment and some reasonable ground level environments.  Often they require power to maintain these conditions; e.g., thermal control and vacuum.  This is especially true with sensitive films.  These films may be exposed to very low temperatures during a ferry flight from EAFB to KSC.  Sometimes special access at the landing site must be developed to retrieve samples.  The option of an EAFB landing is often seen as a burden on the customer, or as extra ground handling operations added by the STS ground operations team to relieve the customer's concern.  A similar problem occurs with life science cargos.  In this case, special ground support equipment (GSE) must be available to perform data acquisition on flight samples, flight crews, animals, etc.  If routine access to KSC cannot be provided, these samples or data collections must be supported with duplicate facilities of the data may be significantly compromised.  Since weather diversions to EAFB will always be a program reality, this risk/cost will always be present.

The turnaround operation nominally consumes approximately 6 days in the flow for that particular Orbiter.  There are occasions when weather can significantly increase this time.  The NSTS Program plans for those 6 days when EAFB landings are scheduled but makes no similar allowance when EAFB landings are the result of a weather waveoff.  Launch date is maintained by extra work once the Orbiter is returned to KSC.

The cost for an EAFB-to-KSC turnaround approaches $1M with several items not included in the cost estimate (GSE, extra security, special cargo handling, etc.).  In addition, the people used to perform the turnaround tasks, i.e, tow, stack and level, mate Orbiter to SCA, demate at KSC, etc., are obtained from KSC and 
Vandenberg Air Force Base (VAFB).  They are pulled off of vehicle flow activities and flown to EAFB to perform the week of activities.  Special GSE are shipped, such as the tail cone, in several truck loads.  The KSC flow for the other vehicles is maintained on schedule by having the other shifts

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