Professional Notes

The Space Shuttle Program—A Proposed Navy Role

By Lieutenant Commander Preston E. Beck, U. S. Navy (Retired), Member, Space Shuttle Task Group, Kennedy Space Center, Florida

In the April 1971 issue of the Proceedings,^[1] this author asked the question, “U. S. Navy: Where Are You?” in reference to the U. S. space shuttle program. A brief listing was also included of technical areas where the Navy should be participating.

The space shuttle program was becoming dynamic even before the recent June 1971 effort by the Soviets to set up a prototype for an earth orbital space station. This Russian effort highlighted the basic purpose of our shuttle program, i.e., multiple flights with space hardware instead of expending most of the hardware on each launch. The shuttle design contractors are now approaching the end of the Phase B (trade-off studies and preliminary design). About November 1971, the National Aeronautics and Space Administration (NASA) plans to start procurement actions on a combined Phase C/D (detailed design, fabrication, and testing). It is now appropriate to present, in more detail, specific areas where the U. S. Navy should be able to make valuable technical inputs to the program.

The size and weight of the space shuttle vehicles has increased since the Professional Note was published. The weight is now approaching 5.5 million pounds immediately before lift-off, and propellants will be consumed at a rapid rate, with a resultant increase in acceleration (constant thrust). The orbiters now feature modified delta wings in order to provide a cross range of about 1,100 nautical miles (distance that can be traversed after re-entry into the earth’s atmosphere).

A major problem that must be settled is the site location(s) for flight testing and subsequent sustained operations. The associated technical problems are more complex and not well understood, even by many engineers.

The basic parameters to be considered that “drive” the design configuration and cost include: mission time and extent of maneuvering (plane changes) in space; launch azimuths, latitudes, longitudes, and altitudes; recovery and mission-abort techniques; type of fuels and oxidizers; safety; and payload. Launch site selection is a factor in most of these basic parameters, and the combination constrains mission planning and the flexibility of the system. A brief examination of these constraints and areas in which the Navy could probably become directly involved follows:

(a) Mission time and space plane changes require an adequate supply of consumables for use by the crew and the engines. Experience in nuclear submarines show a close parallel for life support criteria and fuel management.

(b) The geography of the launch site and the launch azimuths are important. In order to make the best use of the earth’s rotation, the ideal launch would be on a due east heading at the equator from the top of a mountain. There is no area in the United States that meets such criteria, so a compromise must be accepted. Westerly azimuths (retrograde), higher latitudes, and low elevations all tend to reduce the weight of the payload that can be carried.

(c) The ideal site for launch is not the best point for planned recoveries or aborts (emergency landing). Launches for the reference missions result in a westward displacement of the nodal point for each revolution about the earth. The most probable time for an abort condition after lift-off would be the first orbit. As shown in Figure 1, the launch should take place on the east coast if the recovery on the first or second revolution is to take place at an optimum selected location within the continental United States. Most western launch sites would place the orbiter over open water and severely limit the number of available landing sites. One should also keep in mind that if the vehicle has one or more engines inoperative after re-entry, the cross range is reduced and the landing point should be at a very low elevation (sea level). Thus, the question arises as to why not land on the water? The Navy’s experience with displacement hulls rules out that configuration, but the Office of Naval Research (ONR) and the Systems Commands should determine the feasibility of such devices as air entrainment, hydroskis, skids, and hydrofoils. The best device would be one that permits landing on water or a runway. This brings to mind such designs as the Universal Alighting Gear that was tested at the Naval Air Test Center, Patuxent River, Maryland, between 1951 and 1954.

[Figure 1: depiction of various shuttle orbits superimposed on a map of the continental United States]

(d) Fuels and oxidizers require manufacture, transport, and then storage and handling at the launch site. In addition, the type and quantity of such material requires a buffer zone at the launch site in excess of ten miles from the public. What are the advantages of sea transport and barge storage of such materials compared to the present overland methods?

(e) Safety includes not only flight personnel, but also everyone who lives beneath the flight paths for testing, launch, and recovery. It would appear that there are so few uninhabited areas left in the United States, that these types of operations should, where possible, be conducted over water. This would also minimize interference with commercial air traffic. The return of vehicles to the launch site after a landing at another base can also present problems. The limited cross range indicates a need to plan for transport via surface vessels. Forced landings at sea is another problem that still needs competent technical examination.

(f) Payload can only be increased, when the fuel load is held constant, by a reduction in the hardware weight of the vehicles. A need exists to find a means for elimination of the landing gear. The lack of success by the U. S. Navy in using this concept in the case of XF-2Y (1954 era) was the result of structural over-design due to limited empirical data on which to revise the specifications. One should expect that by now, designers can do much better.

This author has discussed only flight activities so far, but other areas also exist that the U. S. Navy needs to support. A transportation study has disclosed that manufacturing is also a problem. The movement of sub-assemblies to the final assembly site involved the handling of very large parts. The structures of the orbiter and booster were divided in 18 groups in Figure 2. Purely on the basis of size, seven of these structures can only be moved by barge or ship. The alternatives are duplication of fabrication facilities, available elsewhere, at the final assembly site or location of the final assembly at a good fabrication area such as St. Louis, Baltimore, New York, Los Angeles, or the like. The assembled vehicles, however, will be larger than today’s aircraft, and can only be moved by flyout or sea transport. The obvious answer is final assembly at the launch site using a seaborne logistic system. Other areas call for development of new materials, testing of components and sub-assemblies, and supporting engineering that exists in such complexes as the Naval Air and Material Center. It certainly seems pertinent that the Navy take the initiative in starting to support the space shuttle program. The key to many of the problems now being subjected to resolution is the sea—the domain of the U. S. Navy.

Figure 2

Space Shuttle
Component Transportation Analysis

Transportation Capabilities

The Helicopter: An Extension of the DE in the Royal Navy

By Commander J. P. Gunning, Royal Navy, Office Director Naval Air Warfare, Ministry of Defence

Today, the influences of a maritime force must make themselves dominant in each of three planes. We must be able to strike, and to repel attack, on, under, and over the sea. Individual responsibilities for this must be carefully divided between the component parts of the force. Indeed, ship and weapons systems design is categorically aimed at fitting specific ship types to take their share of these responsibilities. The whole should represent a balanced force. A predominant need is that, in each of her assigned roles, a ship should be able to assert her influence on the enemy before the converse is allowed to happen. The carrier, demonstrably, fulfills many of the aggressive roles of a force. She can deploy, at long ranges, the ability to detect and strike surface and air vehicles long before they can launch weapons at her. She has, however, little organic protection against the incoming missile or submarine, and for this, she in her turn, must rely on the other elements in the force. It is in the development of escorting units to give this antisubmarine protection that has led, in the Royal Navy, to the evolution of the destroyer escort helicopter.

In general terms, sonar technology allowed the destroyer escort an advance in sonar-detecting range which was not balanced by a commensurate extension of her weapons system. Ships had an increasing chance of detecting submarines before they reached torpedo firing range of the main body. They might even gain detection before the submarine could fire, with confidence, at the escort. Destroyer escort weapons systems, however, continued to curtail this favorable advance in sonar technology. Antisubmarine weapons could be fired only at ranges of about half a mile—by which time the prudent submariner had already launched a decisive salvo at the escort. For up to 20 minutes, the destroyer escort’s commanding officer could know exactly where the submarine was. He might even be aware that the submarine was firing at the main body, but was impotent to do much about it. He might, it is true, approach the submarine with sufficient aggression to deter him during his attacking run. Though often justified, this is a risky business. The crying need was for an ability to attack at medium range. We wanted a weapons delivery system commensurate with improved sonar performance.

Development of long-range, rocket-propelled, air flight vehicles carrying a torpedo payload was started in both the United States and Australia. On each side of the Atlantic, parallel research was put in hand for a torpedo-carrying helicopter solution. And, in the Royal Navy, what emerged was the medium-range, antisubmarine, torpedo-carrying helicopter (MATCH). This is the concept in which a manned helicopter is positively controlled, by the radar of the unit in sonar contact, to a lethal weapon release point. This attack control need not necessarily come from the parent destroyer escort. On the contrary, in its role of force weapons carrier, the MATCH helicopter can, at first detection, be sent to orbit in the area of a contact being investigated by any unit—be it surface ship, submarine, ASW helicopter, or antisubmarine/patrol (VS/VP) aircraft. The helicopter can be poised to attack as soon as the contact becomes refined. A conflict, however, arises between continual preparedness and pilot fatigue. This is resolved by putting the MATCH-fitted ships of the force onto a roster designed to produce, continuously, a proportion of the helicopters at immediate readiness. The resultant flexibility of operations and deployment militates in favor of the MATCH system when compared with the ever-ready but, shorter-ranged, less-flexible and much less-reliable, Dash helicopter.

The MATCH helicopter carries a considerable amount of intelligent autonomy, one hopes. Within the adequate endurance of the aircraft, the pilot can (and does) accept an infinite number of changes of plan. He can remain in waiting, alter weapons settings, avert the danger of an abortive drop, clarify the operational picture, and he might even be able to assist in contact classification. An antisubmarine rocket (AsRoc) capability, or that of its Australian counterpart IKARA, is an undoubted and quick reaction asset which can meet many of the threats of a force. MATCH, however, has also proved an extremely viable and effective system, and does not suffer from the irrevocable nature of the rocket-propelled systems. In a well-balanced force, the two concepts should be complementary to each other.

As the aircraft which evolved with the formulation of the “manned” philosophy, the Royal Navy’s Wasp helicopter has given good service. Much research was devoted to the technique required to release and recover this bird from its shipborne environment. In essence, it was felt that the former procedure must, essentially, be fast and regardless of considerations of ship heading or wind, while the latter could be slower but must be safe.

This safe ability to spring onto, and off, a pitching and rolling deck makes for interesting undercarriage design. Westland Helicopters, Ltd., developed and then evaluated at sea, a range of solutions which included both suckers and skids before finalizing on a broad-based, four-wheeled, arrangement. The wheels are castered and can be swivelled and locked into the 45-degree position. This puts all wheels tangential to the circumference of a circle and allows the aircraft to rotate on deck, where there is an arrangement of quick-release tiedowns. To ensure that the aircraft sticks on deck immediately prior to lift-off and just after touch-down, the pilot can apply reverse pitch to the main rotor.

The safety of the recovery maneuver is a function of the landing reference points visible to the pilot and their relationship to the relative wind. At night, the aircraft must land facing forward and, thus, the ship must then choose a course within 30 degrees of the wind. Night approaches are made down a glide path indicator, which is beamed over the stern sector. An illuminated horizontal reference bar is displayed at the forward end of the flight deck and final touch-down is authorized by a wandsman. Reverse pitch is selected and the tie-downs are attached. Experience has proved this system and Royal Navy statistics exhibit no accidents in 120,000 deck landings. These figures cover day and night operations, in conditions of up to Wind Force 6. Automatic ship stabilization must, undoubtedly, have contributed to the ease with which they have been achieved.

Exercise analysis, repeatedly, has shown the effectiveness of MATCH as a method of torpedo delivery. Control problems can be eased by use of a specially adapted radar scope. The aircraft shows up clearly on the directing radar screen and, through reference to the automatically superimposed position of the sonar contact, it can be accurately directed to the release point.

Apart from the additional value of its role in ASW reconnaissance and the fringe benefits of being a handy vehicle for CaseVac, courier, or essential stores transference, the Wasp has emerged also as having a real part to play in resolving the surface battle. Not only can it search far over the horizon and help with the ever present identification problem, but it has proved its worth in a surface strike role. Fitted with an air-to-surface guided missile system, it has successfully engaged fast patrol boats (FPB) in exercises before they could reach a firing range. Illumination procedures complicate, but do not preclude, this concept at night.

Like the forerunners of all systems, MATCH and the Wasp have highlighted the areas where further development would be productive. Experience, too, has been gained from the deployment, in the guided missile destroyers, of the Wasp’s much larger counterpart, the Wessex Mk3. This sophisticated aircraft (too large for the space available at the stern of most destroyer escorts), constitutes a self-contained tactical unit which can, in addition to a purely MATCH role, play a significant part in the screening and relocation phases and can coordinate and control attacks. The helicopter’s attributes, however, together with those of the Wasp and, in particular of the Wasp’s experiences in the anti-FPB battle must all be considered when defining the roles for the next generation destroyer escort helicopter. In ASW, it would seem obvious that the helicopter need not confine itself purely to extending the torpedo-delivering range of its parent. It could deploy a classification aid and/or a relocation capability. Lightweight sonars and sonobuoy equipment offer an alternative fit for a sonar searching unit. Technology should soon allow, to the parent ship, data processing of helicopter sensor information, and the weight saving thus accrued could be converted into terms of a better weapons payload or endurance.

In the surface role, against an increasing threat from FPB, there are even more radical steps to be taken. The eyeball must be enhanced by a radar set and this, too, has the growth potential for automatic data transference. Arrangements for illumination and identification should become more sophisticated and a blind fire air-to-surface missile system could be fitted.

All these considerations, plus the limitation of an all-up weight of 8,500 pounds have resulted in the Anglo-French Lynx. Due at sea with the Royal and French navies in 1975, this aircraft, like its predecessor, has been developed by Westland. As well as incorporating all that has been gained from their previous experience, the company has introduced several innovations, including a semi-rigid rotor system, a sophisticated flight control system useful for a night dunking profile, and a doppler navigator and display system and a radar set.

The initial Royal Navy outfit is seen as giving the Lynx three main roles in which it can enhance the capabilities of the destroyer escort. In the ASW field, it is a force weapon carrier, which combines a high degree of tactical awareness and flexibility with the ability to classify. It can be despatched in the early stages of a confused surface situation to search out, probe, and identify over a large area of sea. Finally, it can be deployed, either direct from its screening parent or from a barrier patrol, to meet and strike an incoming FPB threat.

It is an aircraft and concept with a considerable application and growth potential. Above all, it represents to the destroyer escort a fast deploying and intelligent extension platform for its sensors and a directional springboard for its weapons systems. It gives DEs the long arm which, in so many fighting situations, can play the trump card.