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A comparative evaluation of the Space Transportation System (STS)-3 flight and acoustic test random vibration response of the Office of Space Science-1 (OSS-1) payload is presented. The results provide insight into the characteristics of vibroacoustic response of pallet payload components in the payload bay during STS flights.
The presently reported effort to provide a single set of standards for the design, analysis and testing of Space Transportation System (STS) payloads throughout the NASA organization must be viewed as essentially experimental, since the concept of incorporating the diverse opinions and experiences of several separate field research centers may in retrospect be judged too ambitious or perhaps even naive. While each STS payload may have unique characteristics, and the project should formulate its own criteria for environmental design, testing and evaluation, a reference source document providing coordinated standards is expected to minimize the duplication of effort and limit random divergence of practices among the various NASA payload programs. These standards would provide useful information to all potential STS users, and offer a degree of standardization to STS users outside the NASA organization.
The stability of the Space Shuttle on-orbit flight control system is determined for a class of payloads for which the payload is tilted out of the orbiter bay and the bending can be modeled as localized at a pivot. Examples are the Inertial Upper Stage or the Centaur with attached spacecraft during deployment. The many inertial, geometric, and jet option parameters are reduced to a smaller set which allows the determination of stability or instability as a function of bending frequency and the other elements of the set. The resulting stability charts, which are presented, can be used by payload designers and misssion planners to predict possible instability without elaborate analysis or simulation.
An input to a study conducted to define a set of carrier avionics for supporting large structures experiments attached to the Space Shuttle Orbiter is reported. The "baseline" Orbier interface used in developing the avionics concept for the Space Technology Experiments Platform, STEP, which Langley Research Center has proposed for supporting experiments of this sort is defined. Primarily, flight operations capabilities and considerations and the avionics systems capabilities that are available to a payload as a "mixed cargo" user of the Space Transportation System are addressed. Ground operations for payload integration at Kennedy Space Center, and ground operations for payload support during the mission are also discussed.
Shuttle payload acoustic environmental predictions for the Jet Propulsion Laboratory's Galileo and Wide Field/Planetary Camera projects have been developed from STS-2 and STS-3 flight data. This evaluation of actual STS flight data resulted in reduced predicted environments for the JPL shuttle payloads. Shuttle payload mean acoustic levels were enveloped. Uncertainty factors were added to the mean envelope to provide confidence in the predicted environment.
The Purdue University GAS-1 payload was flown on STS-7. Results of the three experiments included in the payload are summarized. The experiments conducted were: (1) the detection of nuclear particles in near-Earth space environment, (2) an investigation of the effect of microgravity on the germination of sunflower seeds, and (3) an examination of the motion of mercury under low gravity conditions. Results of the payload experiments are discussed from an engineering design standpoint. Data were obtained from one of the experiments, but electrical and mechanical malfunctions prevented the operation of the other two. The thermal control design maintained the desired temperatures and the structure successfully supported all components. The microprocessor collected and stored temperature readings and other data during the flight. A series of recommendations based on these results are included herein.
The first launch of a Tracking Data Relay Satellite (TDRS-A) on board the Shuttle Orbiter 'Challenger' of the Space Transportation System (STS) provided many pioneering events as a payload/user. The TDRS-A was launched as a payload of the STS as well as a payload of the Inertial Upper Stage (IUS) on April 4, 1983. This paper traces the payload processing flow of the TDRS-A from its arrival at the Kennedy Space Center (KSC), through its launch on Challenger and its trans-orbit flight on the IUS to geosynchronous orbit. The TDRS-A, as a customer/user of these launch systems, is examined and reviewed and lessons learned are noted.
The present investigation is mainly concerned with a reexamination of the Spacelab payload process. The candidate missions are considered in connection with discipline payloads or laboratories. Attention is given to the Space Biomedical Laboratory (SBL), the Space Plasma Lab (SPL), the Astronomy Research Laboratory (Astro), the Shuttle High Energy Astrophysics Laboratory (SHEAL), the Shuttle Infrared Telescope Facility (SIRTF), the Solar Optical Telescope (SOT), the Materials Sciences Laboratory (MLS), the Environmental Observations Mission (EOM), the Shuttle Radar Lab (SRL), the International Microgravity Laboratory (IML), and the Payload of Opportunity Carrier (POOC). The POOC is a low cost means of placing experiments aboard the Shuttle in the cargo bay.
Several full-scale and short-cut methods for analyzing a booster/payload system are presented. Two full-scale techniques are considered: (1) a technique that uses a restrained payload together with a free-booster model, the latter being augmented with residual mass and stiffness correction and (2) a technique that uses a restrained payload and booster model. Both techniques determine the 'modal modes', which require the solution of a system eigenvalue problem; the loads usually are then determined via an acceleration approach. A brief description is given of a number of short-cut methods which are of special interest to Shuttle payload design: structural modification, base drive, and interface impedance methods. Directions for further research and development are suggested.
A comparative evaluation of shuttle liftoff and ground test random response data obtained from the Office of Space Science-1 (OSS-1) pallet payload flown in the cargo bay of STS-3 is presented. The study was initiated to evaluate the possibility that the payload flight vibration response can exceed that occurred during ground test when the ground test acoustic excitation is normalized to the flight acoustic environment. In addition, the analytically derived response from the Vibroacoustic Payload Environment Prediction System (VAPEPS) is compared with OSS-1 ground test results.
As the Shuttle Transportation System (STS) becomes operational, the number and variety of payloads will increase. The need to deploy these cargo elements will require a variety of unique actuator designs, all of which will have to conform with STS safety policy. For those missions where payload operations extend beyond the payload bay door envelope, this policy deems the prevention of door closure as a catastrophic hazard. As such, it must be controlled by independent, primary and backup methods. The combination of these methods must be two fault tolerant. The design of such an actuator is described. The device consists of a single linear ballscrew with two ballnuts, each bellnut forming an independent actuator using the common ballscrew. The design requirements, concept development, hardware configuration, and fault tolerance rationale are highlighted.
This paper represents a brief summary of a report titled, 'Shuttle Payload Bay Dynamic Environments Summary and Conclusion Report' prepared by the Jet Propulsion Laboratory for the NASA Office of Aeronautics and Space Technology (OAST). The report provides a summary of the dynamic environmental data taken during the first five Space Shuttle flights. The present paper is concerned with a brief synopsis of the report's acoustic and high frequency data evaluation, taking into account also an example acoustic prediction method. Attention is given to an acoustic data summary, a vibration data summary, environmental uncertainties, data reduction errors, spatial bias errors, payload effects, spatial variation, flight to flight variation, payload prediction, and an example prediction.
Large geostationary communications platforms were investigated in a number of studies since 1974 as a possible means to more effectively utilize the geostationary arc and electromagnetic spectrum and to reduce overall satellite communications system costs. The commercial feasibility of various communications platform payload concepts circa 1998 was addressed. Promising payload concepts were defined, recurring costs were estimated, and critical technologies needed to enable eventual commercialization were identified. Ten communications service aggregation scenarios describing potential groupings of service were developed for a range of conditions. Payload concepts were defined for four of these scenarios: (1) Land Mobile Satellite Service (LMSS) meets 100% of Contiguous United States (CONUS) plus Canada demand with a single platform; (2) Fixed Satellite Service (FSS) (trunking + Customer Premises Service (CPS)), meet 20% of CONUS demand;(3) FSS (trunking + CPS + video distribution), 10 to 13% of CONUS demand; and (4) FSS (20% of demand) + Inter Satellite Links (ISL) + Tracking and Data Relay Satellite System (TDRSS)/Tracking and Data Acquisition System (TDAS) Data Distribution.
Large geostationary communications platforms have been investigated in a number of studies since 1974 as a possible means to more effectively utilize the geostationary orbital arc and electromagnetic spectrum and to reduce overall satellite communications system costs. This NASA Lewis sponsored study addresses the commercial feasibility of various communications platform payload concepts circa 1998. It defines promising payload concepts, estimates recurring costs and identifies critical technologies needed to permit eventual commercialization. Ten communications service aggregation scenarios describing potential groupings of services were developed for a range of conditions. Payload concepts were defined for four of these scenarios: (1) Land Mobile Satellite Service (LMSS), meet 100% of CONUS plus Canada demand with a single platform; (2) Fixed Satellite Service (FSS) (Trunking + Customer Premises Service (CPS), meet 20% of CONUS demands; (3) FSS (Trunking + video distribution), 10 to 13% of CONUS demand; and (4) FSS (20% of demand) + Inter Satellite Links (ISL) + TDRSS/TDAS Data Distribution.
The Orbiter camera payload system (OCPS) is an integrated photographic system carried into earth orbit as a payload in the Space Transportation System (STS) Orbiter vehicle's cargo bay. The major component of the OCPS is a large-format camera (LFC), a precision wide-angle cartographic instrument capable of producing high-resolution stereophotography of great geometric fidelity in multiple base-to-height ratios. A secondary and supporting system to the LFC is the attitude reference system (ARS), a dual-lens stellar camera array (SCA) and camera support structure. The SCA is a 70 mm film system that is rigidly mounted to the LFC lens support structure and, through the simultaneous acquisition of two star fields with each earth viewing LFC frame, makes it possible to precisely determine the pointing of the LFC optical axis with reference to the earth nadir point. Other components complete the current OCPS configuration as a high-precision cartographic data acquisition system. The primary design objective for the OCPS was to maximize system performance characteristics while maintaining a high level of reliability compatible with rocket launch conditions and the on-orbit environment. The full OCPS configuration was launched on a highly successful maiden voyage aboard the STS Orbiter vehicle Challenger on Oct. 5, 1984, as a major payload aboard the STS-41G mission.
A transient base drive (TBD) analytical method for the support of the preliminary design analysis of Space Shuttle payloads, which could potentially reduce the cost of the payload structural analysis, is derscribed. The validity of TBD predictions depends on the ability to provide accurate synthetic base inputs. Acceleration inputs with a frequency content and magnitude which are not associated with a specific configuration or condition were synthesized. The use of frequency envelopes in the derivation of synthetic inputs can provide appropriate predictions independent of the payload modal frequencies.
To sustain a continued human presence on the surface of Mars or to achieve critical mission objectives the rapid delivery of small payloads may be necessary. Consideration is given to the physics of delivering payloads of about 10 kg over a nominal distance of 1 AU (149.5 x 10 to the 6th km) in 10 days. It is proposed that the most effective method of delivery is the use of a laser lightsail vehicle. The lightsail would be accelerated by a high-power laser from the vicinity of earth to velocities of approximately 174 km/s. Coasting at this velocity for most of the trip the vehicle would be decelerated by a similar laser upon arrival at Mars. The continuous laser power required is calculated to be about 47-billion W and the total duty time of both lasers, determined by optimization of the total energy, is calculated to be 3.9 hours. The laser power scales approximately linearly with payload mass and as the inverse square of the trip time.
In the early stages of spacecraft conceptual design, an investigation of subsystem requirements and their impacts on the total system provides insight into many aspects of the spacecraft design. Such an analysis has been performed on the dual keel space station to examine the system effects contributed by three international payloads provided by the Canadian, Japanese, and European Space Agencies. This example is used to illustrate some capabilities of available computer-driven tools and methods for a system analysis. Two space station configurations were examined, one without international payloads (the baseline configuration for the study) and one with the three international payloads. Each configuration was evaluated to define viewing limitations, rigid body dynamics and controls, structural dynamics, orbit lifetime, environmental control and life support, and thermal management effects. The performance, based on each subsystem evaluation, was then compared for the two configurations, and the results and recommendations are presented.