SORTIE LAB AND CONCEPT VERIFICATION TESTING

INTRODUCTION

Two important complementary activities which address and further define the use of the Space Shuttle in Earth orbital research and applications are the Sortie Lab and concept verification testing. In brief, the Sortie Lab is a payload carrier which will permit scientists to take their conventional ground laboratory equipment to Earth orbital altitudes, use it in their investigations or observations, and return the equipment to Earth for further use. This approach should help to significantly reduce the cost of orbital research and applications. The Sortie Lab, which is in the project definition phase, is now planned for development by the European Space Research Organization (ESRO).

Concept verification testing is a ground test and simulation program designed to assure that future manned orbital operations will effectively and economically support research and applications activities. The CVT project will test breadboard hardware of experiments and supporting subsystems suitable for Sortie Lab and the interfaces of the crew with this equipment.

THE SORTIE LAB CONCEPT

Studies conducted during 1970 and 1971 identified the need for a simple, lowcost payload carrier to enhance the capabilities of the Space Shuttle on sortie missions lasting 7 to 30 days. The Sortie Lab will consist of two major elements, a pressurized manned laboratory module and an external unpressurized platform or pallet on which to mount large instruments and sensors. The pressurized module will provide for experiment control stations, instruments, data recording equipment, and utility subsystems to augment the electrical power, stabilization and cooling provided by the shuttle.

Some sortie missions will require sensors which are too large for containment in the Sortie Lab module, wider viewing angles than possible through a window, or direct vacuum exposure. These sensors, such as telescopes operating in the visible, IR and UV ranges, radio astronomy antennas, or radar antennas will be gimbal mounted externally on either the pallet or the module aft bulkhead. The sensors may be independently stabilized if the experiments require more precise pointing than the basic shuttle can provide.

In the concept shown in figure 174 (see p. 448) the Sortie Lab remains in the Orbiter payload bay and is connected to the Orbiter crew compartment by an access hatch at the front end. The crew, including the mission specialists, payload specialists, and passengers will ride in the Orbiter crew compartment during launch, reentry, and landing operations. On orbit the specialists will normally work in the Sortie Lab module, but their habitability provisions such as the lavatory, combination chair bunks, and galley facilities will all be located in the Orbiter. Once on orbit the payload bay doors will be opened, exposing the Sortie Lab and its associated viewing ports, airlock hatches and sensors. Later study may show that it is advantageous to rotate one end of the Sortie Lab out of the paload bay to obtain a more complete field of view and more heat rejection capacity. In any case, the Sortie Lab will remain attached to the Orbiter vehicle throughout the flight mission. For those orbital missions which do not require the added pressurized volume of the Sortie Lab module to house monitoring and control stations, the pallet can be used attached directly to the Shuttle payload bay forward bulkhead.

One of the principal design objectives of the Sortie Lab is the flexible accommodation of a wide variety of experiments including the kinds of experimental apparatus which a scientist uses in his ground laboratory. This should significantly reduce the cost and time presently required to initiate and conduct space experiments. To this end the Sortie Lab will be designed to supply electrical power at several common levels of voltage and frequency to supply equipment cooling, using either air or water, and to supply a normal 14.7 p.s.i.a. cabin atmosphere of oxygen and nitrogen. The latter will eliminate the need for pressure suits and will minimize many of the special fireproofing measures previously required. The laboratory module is being sized to be used by a staff of four scientists and engineers on one shift. For user programs requiring continuous operations, a larger research crew not to exceed a total of six may operate on two 12-hour shifts.

The pallet, as shown in figure 175 (see p. 448) will consist of a rigid structure with multiple tie-down points for experiments, with fluid lines to provide equipment cooling and with electrical wiring to supply power and control to the experi

ment apparatus. Should a particular payload for a flight require more precise stabilization than available from the Shuttle, standard pointing platforms and gimbals will be installed on the pallet to augment the Shuttle stabilization system. Control moment gyros can be added to the pallet or pointing platforms when very precise pointing requirements extend over a long time, and when the experiment contamination caused by reaction control system exhaust is not acceptable. If access is required to the external payloads during orbital flight either EVA or remotely controlled manipulators may be used.

Based on the studies to date it may be advantageous to configure Sortie Lab so that it can be separated into two functional units, one containing the subsystems such as power, environmental control, etc., and the other unit housing the experiment apparatus. In this way, it will be possible to obtain maximum use of the most expensive portion of the Sortie Lab module by using the one subsystem unit in turn with several different experiment units. The experimenter will have the opportunity to install and check his experiments at his own pace. Additionally, the experiment equipment racks will be modular and removable making it possible for experimenters to install their equipment in the racks at their home laboratories before shipping them to NASA.

Two concepts of modularity are shown in figure 176. In one case the module

can be divided into cylindrical segments by removing the bolts around a full circumference joint. Additional segments can be added should additional volume be needed for experimental activities. In the second concept the structure designed to house the experiments slips in and out of the pressuraizable shell. Subsystems are installed in one end of the shell.

EUROPEAN SORTIE LAB ACTIVITIES

European interest in developing Sortie Lab has grown rapidly since the United States first proposed this activity in November 1971 as a possible focus for European participation in Shuttle era programs. From June through November 1972 concept definition studies were conducted on Sortie Lab by three European industrial consortia under the direction of European Space Research Organization

(ESRO). In November 1972 the European Space Conference (ESC) which is the senior body in Europe concerned with space policy and is composed of the science ministers or their equivalent from member states indicated informally that it would support those countries which were interested in proceeding with Sortie Lab development. Immediately following this meeting the ESRO council authorized $7.5 million to proceed with project definition studies on Sortie Lab and by the end of November 1972 the same three consortia who performed the concept definition studies were under contract for the project definition activities (figure 177). In December 1972 ESC formally committed their support to the

EUROPEAN SORTIE LAB DEFINITION STUDIES

Sortie Lab program and as a result a special spacelab (the European name) project has been formed within ESRO composed of those states which will provide financial support. To date this group includes German, United Kingdom, France, Netherlands, Italy, Belgium, and Spain, and others are expected to join in the future.

In making this major commitment of resources estimated to be on the order of $250 to $300 million, the Europeans have been very concerned about the accuracy of their cost estimates because of the relatively short time they have had to study Sortie Lab. As a result, the United States has agreed to allow them to withdraw from their commitment if the more detailed project definition studies, now getting started, show that the early estimates have been exceeded by an unacceptable amount. However, Europe has agreed not to withdraw after August 1973.

With this commitment, Europe has agreed to design and develop a Sortie Lab compatible with U.S. user requirements, safety and operational criteria, and Shuttle interfaces and to deliver one flight article with ground support equipment, spares and a mockup with working systems all totally funded by Europe. Contingent on determining final requirements, the United States may purchase at least one additional flight article. Details of a formal agency-toagency (NASA to ESRO) agreeemnt are at an early draft stage.

U.S. SORTIE LAB ACTIVITIES

NASA is also conducting a project definition study of Sortie Lab in parallel with the Europeans in order to thoroughly understand the program requirements and to be prepared for experiment integration and operational activities which will follow European delivery of the system to the United States. NASA is conducting its definition study using in-house personnel with the Marshall Space Flight Center assigned the lead center role. The definition study was initiated in May 1972 and will provide a complete preliminary design in the fall of 1973. As critical design features are identified, breadboard component tests will be conducted to provide a sound basis for final component and subsystem design. An example of this type of testing is the current development of a versatile forced air-cooling concept so that ground-based laboratory equipment can be used in the Sortie Lab without modifying it to be compatible with the design concept used in the past (i.e., cold plate cooling).

Identification of Sortie Lab mission uses and user requirements for orbital research and applications is being pursued through working groups of experts representing the scientific and engineering disciplines. The membership of the disciplinary working groups, in addition to NASA representatives, includes scientists and engineers from outside of NASA and as well as representatives from other countries. The charter of the working groups is to explore the uses of the Shuttle and the sortie missions, in the fields of astronomy, solar physics, high energy astronomy, atmospheric and space physics, communications and navigation, Earth and ocean physics, Earth observations, materials science and space processing, sciences, and space technology. The efforts of these working groups as well as similar groups sponsored by Europe will culminate in two or more summer studies starting in 1973 to be conducted by the National Academy of Sciences and the National Academy of Engineering. An important aspect of the sortie mission user studies is that they are iterative with continual reassessment of the engineering practicality and cost of accommodating the experiments. The user requirements which finally emerge from these studies will be reflected in the Sortie Lab detail design and mission planning.

CONCEPT VERIFICATION TESTING (CVT)

Concept vertification testing, which was initially planned for support of the space station concept, is now being adapted to aid in the planning and exploitation of the Sortie Lab. Present plans call for the breadboarding of representative Sortie Lab subsystems now being defined in European and American studies. This will permit the simulation of Sortie Lab interfaces involving experimenter/ user and the host Shuttle Orbiter. Typical candidate experiments will be selected and breadboard hardware will be fabricated (figures 178 and 179) (see p. 452) with emphasis on the following aspects of experiment activity:

1. Planning and preparation time. (Can this activity be cut to a matter of weeks?)

2. Utilization of existing systems. (Can research and applications apparatus and associated computer software, already in use in Earth laboratories, be accommodated with little modification?)

3. Utilization of off-the-shelf commercial equipment. (For example, can standard test instruments be used with little or no adaptation?)

4. Commonality. (Can experiments to be grouped on the same Sortie Lab flight utilize common laboratory or test equipment and software?)

5. Operations costs. (Can experiment integration, checkout, and maintenance needs be reduced compared to present practice?)

6. Documentation and procedures. (Can these sources of cost be significantly simplified so as to improve the utility and availability of the Sortie Lab to the scientific community?)

This work will be complemented by the Airborne Science Shuttle Experiment System Simulation (ASSESS) program at the Ames Research Center where jet aircraft are being used as platforms for the conduct of scientific research and applications activities. ASSESS is the special program for translating the best features of the airborne research program into shuttle sortie mode planning. Early results of both ASSESS and CVT will aid immeasurably in NASA and ESRO Sortie Labor definition and design studies.