AIAA - American Institute of Aeronautics and Astronautics
Scope
"Introduction General Critical to establishing the required scope of space launch integration (SLI) for a spacecraft (SC) program is fully understanding the complexity and criticality of the specific SC system and performing a comprehensive assessment of the risks associated with launch. A considered approach should be one that includes: ? An understanding of the consequence of launch failure ? A process to identify and handle risk commensurate with the established risk tolerance Essential elements of any launch integration effort are clearly defining the roles and responsibilities of the organizations involved and ensuring the contracts and supporting agreements are consistent and in place before beginning the integration effort. A SC customer or launch service customer must determine the level of insight and/or oversight that will be applied to the space launch integration process. As part of the determination@ the customer or sponsoring organization must weigh the value of applying oversight in his efforts to mitigate the risk of a launch failure. Commercial SC objectives are primarily focused on establishment of a revenue stream when the SC achieves its operational orbit. Commercial SC are based largely on existing@ evolving@ commercially available SC buses@ with payloads designed to achieve specific commercial program objectives. The time frame for the integration and launch of a commercial SC can vary from several months to several years@ depending on the maturity of the SC and launch vehicle (LV) systems@ and the complexity of the SC-to-launch system interfaces. The space launch integration community for these types of programs is typically comprised of the launch service provider@ the SC manufacturer@ the SC customer@ the launch range operator@ and sometimes a launch service integration contractor (LSIC). Commercial SC may be comparatively less expensive and able to be replaceable in the event of a launch or on-orbit failure. National defense@ scientific@ and experimental SC@ on the other hand@ are typically designed to fulfill a specific mission@ and generally comprise unique SC bus and payload configurations designed to achieve specific mission objectives of national interest. These SC are typically one-of-a-kind in nature@ very expensive@ and require a significant span time to replace in the event of a launch failure. Additionally@ a launch failure may result in a lost opportunity to achieve a specific mission objective@ as in the case of an interplanetary SC@ or may result in a reduction in national defense capabilities@ as in the case of a national defense SC. SC such as these typically involve complex@ unique interface requirements relative to the LV system@ and as a result@ may require a space launch integration span time of several years. These SC systems typically trend toward increased levels of oversight into the launch integration process@ involving numerous organizations. These organizations may include customers@ SC contractors@ launch system integration contractors@ LV contractors@ launch service program offices@ independent validation and verification contractors@ and LV and SC technical advisory contractors. The purpose of these contractor organizations is to mitigate risk and enhance mission success. In summary@ mission assurance for commercial SC typically relies on balancing risk@ which may be revenue@ with the cost of insurance. For missions with national security or science implications@ the risk associated with loss of mission is entirely different and must be addressed appropriately. Additionally@ each program should have a clear understanding of and an established method of ""insight"" and ""oversight@"" the cost and schedule implications of each@ and a mechanism in place that accommodates implementation of either or both@ as appropriate@ to achieve the required level of risk mitigation. There are various methods/approaches to accomplish space launch integration. The level of effort required for any launch integration process is dependent on many variables: ? Maturity of the systems involved ? Complexity of the interfaces ? Security implications ? Risk tolerance Careful consideration should be given to each of these areas and a decision made as to the accommodation of each in the space launch integration process. As an additional consideration@ there are various perspectives regarding the best method and approach to launch integration. The perspective will vary with the various organizations involved and their respective roles and responsibilities. Relevant background information on various aspects of the integration process is included herewith in Annexes A@ B@ C@ D@ and E. Mission The overarching consideration for any program is the SC mission objective. The achievement of this objective establishes the requirement(s) for the SC design and drives the launch integration process. Careful consideration must be given to each element involved in the program@ factoring in the perspective of each element and developing a method to accommodate each@ as appropriate@ for the specific program. Customer Perspective The customer's goal during the integration and launch phase of a program is to deliver a functional payload with fully operational satellite bus to an orbit that meets mission objectives. The launch service is of secondary concern to the SC customer. It is natural for each organization@ customer/payload designer@ upper stage designer@ launch service provider@ and launch facility operator to consider its own area of interest as having the highest priority. However@ the primary objective for all parties involved should be to deliver the SC to the correct orbit@ within all environmental constraints@ and to maximize the probability that mission objectives will be achieved. SC Perspective From the SC perspective@ launch is the single most traumatic event in the life of the program. The launch environment generally presents the most severe conditions that the SC will experience. These conditions drive many aspects of the SC design@ especially the SC structural design. Launch constraints often present design challenges@ which require complicated design solutions to fit within a confined payload fairing (PLF) envelope and provide for post-launch operations. Low-mass design techniques and mass conservation measures may be required to stay within LV performance capabilities. Recommended Practice: Because of these technical challenges@ it is in the best interest of the SC contractor to have early and reliable definition of LV interfaces and available SC accommodations as well as performance capability to the desired orbit. Recommended Practice: Changing launch requirements will affect SC program costs and schedule@ especially when they occur late in the cycle. Hence it is advisable during the early design SC process to make sure it is compatible with more than one type or class of LVs to preclude excessive delays due to the stand-down of one. A spacecraft design that is compatible with several LVs can also be used on different mission applications@ which can be very beneficial with regards to both cost and schedule savings. Launch Systems Integrator Perspective For security or other specific purposes as described in Section 1@ certain programs require the involvement of a launch systems integration contractor (LSIC) to represent the SC contractor in the launch integration process. In these programs@ the LSIC becomes the designated interface between the SC and launch service communities. The LSIC represents the SC side of the SC-to-LV interface and is accountable to its customer to define all interface requirements and certify that they are properly verified. This responsibility includes coordinating the development of integration schedules and plans@ specifying SC requirements@ performing interface verification@ and coordinating integration activities with all participating contractors. Because a separate LSIC does add significant overhead and cost to a program@ it should be used only after careful consideration. If employed@ the LSIC is responsible for mission success of the SC-to-LV interface for all phases from pre-launch through orbital insertion and SC separation. The LSIC may co-chair the technical working groups with the launch service provider for the purpose of developing the SC-to-LV interface and certifying completion of the verification tasks for the SC-to-LV interface requirements. Launch Service Provider Perspective The launch service provider is responsible for the launch system design@ production@ and delivery@ ensuring that the launch system capabilities accommodate the agreed-upon SC/LV interface requirements. The launch service provider is responsible for the integration and checkout of the launch system components@ launch operations@ and LV ascent through orbit insertion and subsequent disposal@ or return@ activities. The launch service provider@ in conjunction with the SC contractor and customer@ and other launch integration participants as necessary@ implements and verifies the SC-to-LV interface requirements. For missions that use a LSIC@ the launch service provider fulfills the role of the launch vehicle integration contractor (LVIC)@ representing the launch system side of the interface@ with the responsibility of certifying that the launch system will successfully place the SC in its desired mission orbit. The LVIC co-chairs the technical working groups with the LSIC for the SC-to-LV interface and conducts the verification tasks for the LV side of the interface. Specifically@ the LVIC publishes and maintains the SC-to-LV interface control document (ICD) and plans and conducts verification of launch system side of the SC-to-LV interface requirements. In addition@ the LVIC maintains the ICD verification database and closure library@ archives all the evidence used for verification closure@ and in the absence of a LSIC represents the final approval authority on all verification closures for the ICD. Space Launch Integration Process The success or failure of a mission may be related to the launch integration or it may be attributable to some other aspect of the launch operation. A rigorous@ comprehensive launch integration process will not guarantee a successful mission but it will reduce the risk that a SC-to-LV interface anomaly will cause a mission failure. The key is to develop a process that will reduce risks inherent in the launch integration process to an acceptable level. Identifying all the risks and establishing the acceptable level for each risk is much easier said than done. It is especially difficult for complex interfaces and where multiple systems are involved. Another consideration is that@ for some missions@ cost and schedule considerations are secondary to the need for reducing the risk of failure to the absolute minimum. Recommended Practice: It is therefore critical that a comprehensive and clearly defined process be established as early as possible@ using a formal risk-management isk-mitigation process@ as discussed in the Mission Assurance/Risk Management section of this document. Once the risks are understood@ at least at the program level@ a determination can be made as to the level of launch integration required to address these risks. The launch integration process must address other interfaces to the SC; e.g.@ with transportation systems@ processing facilities@ launch site facilities@ and flight operations centers. The process must incorporate required safety policies and practices into all aspects of the integration process. The responsibility for covering each of these areas can be assigned to one contractor or divided among multiple contractors@ depending on the customer requirements@ complexity of the interfaces@ and contractor agreements. Recommended Practice: A comprehensive launch integration process begins with assessing the compatibility of SC system interface requirements relative to launch system capabilities and focusing on interface issue resolution to minimize overall cost to the customer@ while emphasizing risk mitigation in interface design to enhance mission success. The process culminates with the successful delivery of an operational SC to the desired orbit. For highly complex missions@ the launch integration organizational structure may include various agencies representing the SC contractor@ LV contractor@ payload contractor(s)@ and launch site. In addition@ vehicle and support contractors as well as consultants may be involved. This participation will vary depending on the ""oversight"" and ""insight"" required by the sponsoring organization. For some programs@ the customer may want one contractor to provide the total mission service where delivery of an operational SC to the specified orbit is the contractual requirement. Other customers may require a SC contractor@ a LV contractor@ and a LSIC. Figure 1 illustrates the basic launch integration process involving a LSIC. This process begins with technical and operational interface requirements that typically flow from the spacecraft vehicle contractor (SVC)@ through the LSIC (if one is being used)@ then to the LVIC. Return flow consists of capability assessments@ which include updated design information. These assessments go back through the LSIC to the SVC@ thus completing a single iteration of the integration process that will eventually lead to the definition of a compatible interface. Formal documentation and control of the agreed interfaces is established in an ICD@ as described in Section 5@ Requirements and Verification. This process forms an active loop supported by trade studies@ analyses@ and impact assessments performed@ as required@ by the various contractors. This loop is closed only when a compatible interface is achieved. "