Assuring Access to Space

Nov. 1, 1984

Total Defense Department spending on space systems and related facilities grew from $8.3 billion in FY ’83 to $9.2 billion in FY’84 and can be expected to reach almost $12 billion in the coming budget year. Central to the military space mission — and the attendant costs — is the philosophy governing what should be launched, and for what purpose.

Early this year, Defense Secretary Caspar Weinberger put into effect a Defense Space Launch Strategy that strikes a balance between technical and economic constraints and operational requirements. Although this new strategy recognizes the importance of assured access to space across the spectrum of conflict, there is the pragmatic admission that “the ability to satisfy this requirement is currently unachievable if the US mainland is under direct attack.” By default, therefore, the assured launch capability is limited to “levels of conflict in which it is postulated that the US homeland is not under direct attack.” For the time being, the new strategy seeks to bridge this gap by keeping spare satellites on orbital standby and other measures that help ensure orbital standby and other measures that help ensure “sustained operations of critical space assets after homeland attack.”

A fundamental element of the launch strategy — and the Defense Space Policy that it is a part of — is the recognition of the need for launch capabilities that can back up the Space Shuttle in case of “unforeseen technical and operational problems” and “for operations in crisis and conflict situations.” The new launch strategy stresses the Defense Department’s commitment to the Space Shuttle, but at the same time warns that total reliance on that system “represents an unacceptable national security risk” because of technical and operational uncertainties attending the Shuttle. Also, “a complementary system is necessary to provide high confidence of access to space, particularly since the shuttle will be the only launch vehicle for all US space users. In addition, the limited number of unique, manned Shuttle vehicles renders them ill-sued and inappropriate for use in a high-risk environment.”

Requirement for ELVs

The initial requirement that results from the Defense Space Launch Strategy, according to Under Secretary of the Air Force Edward C. Aldridge, Jr., is development of a new expendable launch vehicle (ELV) that can be available by the 1988 and that will be more capable than any existing ELV in meeting future payload requirements. Senior officials of AFSC’s Space Division told Air Force Magazine that it is imperative to be able to launch certain essential low-orbit satellites in time of conflict without exposing the Shuttle and its crew to war conditions. There also is no logic to using the sophisticated Shuttle as a straightforward boost vehicle. Yet there are many national security payloads to be orbited over the next decade that require only simple launch service on a reliable, “least-cost” basis. From the Space Division’s point of view, “we want to take the most cost-effective, most reliable ride to space.” The requirement is for ten ELVs, starting in 1988.

Three candidate designs are under consideration at this time — the Titan 34D7, Atlas II, and SRB-X, a design proposed by NASA. Any of these three ELVs would be capable of delivering a minimum of 10,000 pounds into geosynchronous orbit. (See also “In Focus,” August ’84 issue, p.20.)

Three basic benefits would ensue from the proposed new ELVs, according to Secretary Aldridge. First, they provide a prudent hedge against unforeseen Shuttle problems, “whether they be technical, production, or vulnerability — any one of which could result in catastrophic loss or fleet groundings.” Second, ELVs furnish “launch-on-demand” flexibility for key national security payloads and, at the same time, reduce “the launch-on-demand pressures on NASA that avoids DoD invoking our higher-priority bumping rights to the consternation of commercial and foreign customers of the Shuttle.” Lastly, he believes that the use of ELVs allows the US to maintain an industrial base for space launch vehicles that will otherwise disappear and leave the field entirely to foreign competitors.

The point is, he contends, “that we as a nation are losing a vital national resource. No new contracts are being awarded for procurement of space launch systems. The fourth and last Shuttle Orbiter will be delivered this year, and key ELV lines are coming to an end. We don’t believe this is a healthy or acceptable situation for the Department of Defense or the nation.”

The Administration’s pleas for “commercialization” of ELVs, aimed at maintaining space transportation leadership by encouraging the private sector to initiate commercial launch operations, have so far fallen on deaf ears. Without large, up-front investments by the Defense Department in such a joint venture, the commercial sector is apparently not willing to run the risks associated with this approach. The Defense Department, as a result, will have to launch a conventional development and procurement program if it wants to acquire the ten ELVs deemed essential for backup of the Shuttle. The trouble, of course, is that this will require large investments in 1986 and 1987, tight budget years marked by peak funding requirements on the part of already approved programs, according to Secretary Aldridge. The start-up requirement for the proposed ELV program in FY ’85, according to Space Division estimates, is $35 million, a figure that would climb to about $315 million, a figure that would climb to about $310 million in FY ‘86.

Support for the program in Congress, OSD, and even the Air Force appears to be shaky. The all-powerful Defense Resources Board has not yet ruled on whether or not the ELV program is to be funded. The Air Force recently asked industry to submit revised proposals that allow for various funding levels and schedules.

Space Launch Plan 2000

The new Defense Space Launch Strategy, in addition to naming the Air Force the executive agent for running the ELV program and the associated payloads, also charges USAF with development of a “comprehensive space launch plan to meet projected national security requirements through the year 2000.” Once approved by the Secretary of Defense, these Air Force recommendations will be incorporated in the FY ’86 Defense Guidance Plan.

The long-term segment of the Defense Department’s launch strategy, covering the period beyond the early 1990s and the initial phase of the ELV program, involves efforts to “ensure that future national security space missions are not constrained by inadequate launch capability.” The Air Force evaluation “should examine potential DoD launch requirements, such as the need for a heavy lift vehicle, and should attempt to take maximum advantage of prior investments in the US launch vehicle technology.”

Secretary Aldridge informed Congress recently that “we have system concepts, such as the Strategic Defense Initiative, that may require launch vehicles capable of placing 100,000 to 250,000 pounds of outsize payload in low earth orbit. Development of launch vehicles of this size will require a great deal of development and engineering work. We have requested in the FY ’85 budget to begin requirements definition for this extremely large booster. We are participating in an Aeronautics and Astronautics Coordination Board study with NASA to define joint requirements for such a vehicle.” Such a heavy lift booster, he pointed out, “would also fill the need for a complementary launch system to provide the DoD with a continued assured access to space.”

The Space Division sees the proposed heavy lift booster primarily as a means for making as low as possible the cost per pound of payloads delivered to orbit. This criterion suggests designs relying heavily on the recoverable and reusable components as well as on compatibility with the Shuttle facilities now nearing completion at Vandenberg AFB, Calif.

Within the next ten years or so, the need to provide what Secretary Aldridge terms the “robustness and flexibility of the key nodes of our defense space posture” is likely to become pronounced. One of the key nodes that causes concern “is the single Shuttle facility at Kennedy Space center,” he points out, adding that “it seems undeniably unwise for the nation’s entire Shuttle fleet to be tied to a single facility, so we are working hard to complete the West Coast Shuttle facility at Vandenberg AFB, [which] is also vital for the accomplishment of polar and retrieval missions not possible from the Kennedy Center.”

Another key node in need of back up is the single central control facility for on-orbit control of all national security satellites at the Space Division’s Sunnyvale, Calif., facility. All remote tracking stations around the world feed data into that facility. The Consolidated Space Operations Center (CSOC) now under construction at Colorado Springs, Colo., will provide a “much needed complementary satellite control capability for the Defense Department, [with the result that ] instead of a single facility located in an earthquake-prone area, we will have two first-class facilities, both working and sharing the load on a daily basis — a far healthier situation.”

Return of the Tug

The Inertial Upper Stage (IUS), the spacecraft that takes payloads from the Shuttle or ELV to high-energy orbits — including the high altitudes required for geostationary satellites — in the past encountered rough going technically as well as in terms of cost. The prevailing notion at AFSC’s Space Division is that the program has cleared these hurdles and “is coming along quite well.” Thermal and gas leakage problems that have plagued the design appear to have been solved, and the IUS is scheduled for launch on December 8 of this year. The unit cost of IUS, however, will be higher than originally planned. The reason is that, with the decision by NASA to procure Centaur upper stages for certain missions rather than uprated versions of the IUS, the originally envisioned economies of scale have been diluted.

There is high confidence on the part of AFSC’s Space Division, however, that the IUS will turn out to be one of the most reliable upper stages the country has ever built. If the buy of the IUS is curtailed, Space Division spokesmen stress, “it will be for reasons other than inadequate performance of insufficient reliability.” Refuting NASA insinuations to the contrary, the notion at the Space Division is that “none of us is immune to propulsion problems when it comes to upper stages. We all have had them, and in the IUS we are building really sophisticated hardware that, not surprisingly, had initial growing pains.”

Beyond IUS and the Centaur-based upper stage, the Space Division remains “open-minded” with regard to the eventual need for a “space tug,” a vehicle that could deliver sizable payloads to geosynchronous orbits and retrieve them for repair or modification. The requirement for such a system will probably be determined by economic considerations — in the main, the cost-effectiveness of repairing and refurbishing geosynchronous spacecraft on the ground and then relaunching them. If such a space tug is manned, on the other hand, it might be possible to repair and refurbish some satellites in orbit. No decision has been made on which form of tug should be explored or whether or not such a vehicle will be needed in the first place.

Antisatellite Interceptors

The Space division is developing — but because of congressional strictures has not been able to test against space targets — an antisatellite (ASAT) interceptor. Such a weapon, Secretary Aldridge points out, is needed to “deter threats to our space systems and, within the limits imposed by international law, to counter certain satellites that provide direct targeting support for hostile military forces.” Unlike the operational, thoroughly tested Soviet space weapon that is a ground-launched co-orbital intercept satellite, the US ASAT is a miniature vehicle on a two-stage SRAM/Altair booster carried aloft by and launched from specially modified F-15s.

The present US ASAT system, the Defense Department reported to Congress, “will not have the capability to attack Soviet early warning satellites, even at a low point in their orbit.” The Air Force is funding at low levels — to the tune of about $500,000 in FY’85 — studies to examine “concepts for improvements to the current ASAT system and other promising technologies which might have ASAT application for the future, but [it] has no [efforts under way] to select specific follow-on ASAT systems with a high-altitude capability.” Carrying the US ASAT forward to operational status, according to Secretary Aldridge, is imperative to “correct a glaring basic imbalance of capabilities between us and the Soviets.”

The Soviet Union, according to Pentagon reports to Congress, has “several systems or technological capabilities either designed for an ASAT mission or having the inherent potential for such a mission. These include the co-orbital homing ASAT interceptor that has been operational for twelve years, the Galosh ABM interceptor, and electronic warfare systems. The USSR could have some additional so-called ‘residual’ ASAT capability in equipment amenable to undetected or surreptitious development to operational status, or to a status that would permit rapid breakout.”

There is concern in the Defense Department that the USSR, under the guise of carrying out routine rendezvous and docking operations in space, might “develop spacecraft equipped to maneuver into the path of, or detonate next to, another nation’s space craft. Other types of systems with inherent ASAT capabilities include ballistic missiles with modified guidance software as well as space boosters with nuclear payloads.”

Other future Soviet efforts “that could produce specialized ASAT systems include developments in directed-energy weapons, space planes, and space stations. Directed-energy weapons could pose difficulties because, for example, a space-based weapon developed for air defense or ballistic missile defense would be even more effective as an ASAT weapon than in its primary role.”

The cost of the US low-orbit ASAT system, according to Defense Department reports to Congress, is estimated at $1.3 billion in research and development and $2.5 billion in procurement. The initial operational capability will probably consist of twelve ASAT interceptors and four modified F-15s. The current version of the air-launched miniature vehicle (ALMV) ASAT, Pentagon witnesses told Congress, could eventually be given greater altitude capability by using either a larger first or second stage, or a combination of both. Such a development would take about four or five years and cost about $600 million. There is also the option to adapt the ALMV to a ground-launched booster. The eventual selection of a particular booster, such as MX or D-5 (a large SLBM under development by the Navy), would depend on specific mission requirements — in the main, altitude, survivability, and negation times — associated with such a future design.

While the Joint Chiefs of Staff foresee no near-term requirement for US ASAT capabilities beyond those incorporated into the current design, advances by Soviet space systems in the future will have to be met by commensurate boosts in US capabilities. This applies both to the US ASAT’s ability to deter Soviet attacks on this country’s space systems as well as to conventional deterrence by putting at risk Soviet satellites that would support Soviet terrestrial and naval forces directly in the event of conflict.

Over the longer term, one or two decades hence, Secretary Aldridge believes it might become necessary to allow for a “potential shift of emphasis of our space-based systems from a generally accepted mission of support and force enhancement to a mission of force application — that is, weapons in space.” He stressed that “any development of space weaponry must, of course, be consistent with national policy, international law, and national security requirements.”

Spacecraft Survivability

While the distances of space generically provide satellites with some survivability, these system and their ground nodes are far from invulnerable. The Space Division’s favorite metaphor is that satellites “are nothing more than very tall relay towers.” AS Secretary Aldridge put it, “The survivability of our space assets must be commensurate with the value and utility of the support they provide the National Command Authorities and our operational military forces.” Toward this end, various survivability measures are being incorporated in vital new spacecraft, including proliferation of satellites, extremely high orbits, maneuver capability, and hardening.

At the same time, “We are pursuing technology programs for space computers, on-board processing, autonomous operations, and on-orbit mission extension,” according to Secretary Aldridge. These space-based improvements, he stressed, are tied to corresponding improvements for ground facilities: “Mobile mission ground stations with survivable telemetry, tracking, and command capabilities will become more available as we close out the decade. Together with jam-resistant, redundant communications links, our overall space posture in a conflict” is slated for dramatic improvements. The direct beneficiaries are the military combat commanders, who “will have continuing access to a steady stream of real-time, dependable, and accurate information [across] a broad range to support needs.”

Among the first space systems to receive enhanced ground terminals are the early warning satellites of the Defense Support Program (DSP). By the end of next year, the Air Force expects to have completed production of DSP’s mobile user terminals that will provide “hardened, jam-resistant links with the users,” Secretary Aldridge said. Broad, in-depth survivability measures are being grafted on the Milstar (Military Strategic and Tactical Relay) satellites that are being developed by AFSC’s Space Division.

The Milstar System

While the Milstar constellation is still evolving, current plans call for at least four operational satellites hovering in geosynchronous orbit at 22,300 nautical miles above the Indian Ocean, the East Pacific, the West Pacific, and the Atlantic, respectively, as well as two or more in highly elliptical orbits to cover the polar regions. The Milstar satellites will be equipped with substantial maneuver capabilities and sufficient propellants to carry out evasion and escape repeatedly and flexibly to elude Soviet ASATs. The Milstar satellites will also be hardened to as high a degree as practicable against nuclear effects and radiation from future directed-energy weapons.

The use of “high orbital spares” — meaning dormant, dark satellites parked at altitudes as high as 110,000 miles (five times as high as geosynchronous orbits and the altitude beyond which the earth’s gravitational pull becomes to weak for keeping objects from drifting off into deep space) — is under consideration for Milstar, but has not been decided on as yet by the Space Division. Over the long term, as Soviet ASAT and related capabilities grow, it might become necessary to deploy new generations of Milstar satellites exclusively in such “supersynchronous” orbits. Such an eventuality is probably a long time off and would not require a major redesign of the key components of the system.

Lastly, Milstar, like most other future satellite systems, will incorporate “cross-orbital relay” features that interlink individual satellites with one another. As a result, flexibility, result, flexibility, redundancy, and, most importantly, survivability are boosted while dependence on groundbased relay and tracking stations on foreign soil is reduced or eliminated.

Milstar’s development phase is in its second year and, according to senior Space Division officials, is on schedule and progressing smoothly. Lockheed is the prime contractor, supported by TRW and Hughes.

Other Survivability Measures

Since data of one sort or another are the raison d’être of most military satellites, the survivability of the information is as important as that of the spacecraft or the associated ground terminals. If, in an operational sense the survival of the ground stations is a key concern, the first obvious step is to make them mobile, highly transportable, and redundant. A number of design characteristics ensue from these requirements. For one, the antennas will have to be kept relatively small to ensure mobility or transportability. By extension, this means that the data stream must be kept small.

The concomitant requirement is to perform some data processing aboard the spacecraft and to send only essential information to the ground over data links with a low error rate and a narrow bandwidth to provide jam-resistance. This does not mean that spacecraft will soon be transformed into “orbiting computers” that have to function in a thoroughly fail-safe fashion; it does mean that, in the words of a senior Space Division official, “We want to be able to do more and more on-board data sorting.”

The Pentagon’s concern with survivability of a different kind is reflected in the mutations of the Defense Satellite Communications System (DSCS). Of the eight DSCS satellites in orbit at this time, seven are of the DSCS II type, while one is a new, more survivable DSCS III spacecraft. The DSCS III “upgrades” involve mainly nuclear hardening and anti-jam (AJ) capabilities. The latter category includes advanced encryption protecting the data links and sophisticated antenna “nulling” to blank out jamming sources. The DSCS III satellites — an eventual buy of fourteen is programmed — are equipped with sensors that instantly spot jamming, report this fact to a ground station, and then wait for the ground station to plot the location of the jammer and to ground station to plot the location of the jammer and to instruct the satellite how to “null” the jammer. The intrinsic advantage of this arrangement is that the major computer elements, the “smarts” of the system, are on computer elements, the “smarts” of the system, are on the ground rather than on the satellite where weight, space, and power are at a premium.

The DSCS III satellite design recently passed rigorous tests of its nuclear hardening features. The hardness levels of the design meet all the criteria for resistance to collateral nuclear effects — but not direct attack — specified by the Joint Chiefs of Staff. Included are the ability to withstand low-level flash effects, X-rays, gamma rays, and EMP (electromagnetic pulse). DSCS III uses “S” and “X” band links that, while not as resistant to nuclear effects as EHF (extremely high frequency) communications links, are considered adequate for near-term applications.

Over the longer term, OSD requested the Defense Communications Agency to examine concepts for a successor to DSCS known as the Follow-on Wide-Band Satellite System, which might use EHF data links. Complementing the increased survivability of DSCS III’s space segment will be new transportable and mobile ground terminals. Some of these terminals are designed to be air-transportable aboard C-130 aircraft; others, tailored for the US Central Command, are ground-mobile and use small five- to fifteen-foot-size antennas.

One of the most challenging satellite systems in early concept formulation is the co-called Boost Phase Detection and Tracking System, a key element of the Strategic Defense Initiative (SDI). This follow-on to the aging Defense Support Program had originally been called the Advanced Warning System. The Boost Phase Detection and Tracking System will serve both SDI and other users. The Space Division, in concert with the SDI program office and other Defense Department elements, is working on initial definition studies for this system.