National Launch System - NLS

In April 1991, the president's National Space Council (NSpC) directed a joint DOD/NASA program to develop and procure a family of launch vehicles and supporting infrastructure to meet civil, commercial, and national security needs.⁽¹⁾ The national launch system (NLS) effort was aimed at providing NASA and DOD with a capability to deliver a wide range of payloads to low-Earth orbit at a low cost and with improved reliability.

Gen John L. Piotrowski, commander in chief United States Space Command, described the US military launch infrastructure as lacking characteristics key to other military forces: combat readiness, sustainability, and force structure.⁽²⁾ In recent years, a series of unfortunate events highlighted the fragile nature of the US launch infrastructure (the Challenger tragedy and the explosion at a solid motor propellant plant that destroyed more than half the nation's space and tactical missile propellant production capability). As a result of these problems, the NSpC outlined a national recovery plan. This plan rejects sole dependence on the shuttle for access to space and places emphasis on basic technology by calling for designing and building a new booster to meet the needs of US launch activities. This new booster was to be cost-effective and efficient for peacetime launch, as well as survivable and responsive to the needs of combat forces.

The NLS was aimed at achieving a reliability of 98 percent or higher with a launch-on-schedule probability of at least 95 percent, vehicle availability of 90 percent or better, a 30 day or less launch response time, and a surge capability that will accommodate seven payloads within a five-day period.⁽³⁾ The NLS family of launch vehicles was based upon a set of common building blocks that can combine into different vehicles. The Air Force reviewed three vehicle specifications. Designing common modules and using existing launch system elements will minimize NLS costs. The modules would be usable on different vehicles in the family without changing subsystems or redoing major qualification tests. This feature lowers production and operation costs. High-value avionics, control subsystems, and the main engines are integrated into a propulsion module that represents the large majority of the launch vehicle's total cost. This module also allows recovery and reuse of the high-cost hardware.

To achieve NLS cost, operational flexibility, responsiveness, and reliability goals, contractors looked closely at both the technology and process involved in launch vehicles. Area contractors reviewed on-site assembly of vehicles, launch pads (repairs and numbers), automation of vehicle/payload integration, adaptive guidance and control systems, and ground flow operations and analysis.

On-site assembly of vehicles before they are positioned on a launch pad would reduce pad time, enable a multi-processing capability, and facilitate the exploitation of built-in autonomous testing and processing. Months of final assembly and payload integration, all done on pad, inhibit rapid response to operational requirements.

Prelaunch preparation and postlaunch refurbishment time requirements dictate a large number of pads. Adding flexibility to launch scheduling and allowing faster launch responsiveness in a crisis requires more launch pads and simplified launch structures. Pad redundancy would alleviate the risk of being denied access to space for certain payload/booster combinations and cover a launch catastrophe that could disable a pad for months.

Launch vehicle processing has historically employed large numbers of analysts for data monitoring, diagnostic interpretation, maintenance repair, mission planning, and real-time problem solving. The entire process of booster and payload testing, processing, and launch is lengthy, manpower intensive, and inflexible. An automated monitoring and testing system that can calibrate, process, store, and notify the user of which subsystem has failed and needs replacement could reduce the lengthy integration process time considerably. Building in more software sophistication for launch guidance and control systems would enable a vehicle to adapt to changes it senses in flight without human intervention. In addition, design of a redundant, multi-string guidance and control package using lower cost components would reduce the expense associated with the current single string guidance package, which requires tightly screened electronic components.

Low-cost ground operations require an automated system to document and manage ground operations, monitor health status, and perform fault isolation down to the lowest repairable unit. A set of automated test hardware embedded within the vehicle would be needed. The goal would be to develop systems that allow subsystem monitoring and diagnostics on a continuous basis and subsequent unit replacement with minimal time lost.

NLS Plans⁽⁴⁾

NLS planned the development of a new family of launch vehicles to meet the broad range of national security, civil and commercial launch needs anticipated for the next century -- with the initial launch of the first configuration of NLS planned for 2002.

NLS consisted of the following major elements: the space transportation main engine (STME), a highly reliable, low-cost engine that will provide 650,000 pounds of thrust; a family of three new launch vehicles to capture the primary classes of payloads anticipated for the next century; a high-energy upper stage to provide capability to geosynchronous orbits; a cargo transfer vehicle for transporting payloads to the Space Station Freedom; new launch processing facilities and launch pads at Cape Canaveral Air Force Station, incorporating important operability features; and some modified and new facilities at the Kennedy Space Center.

The NLS 1 vehicle would deliver 13,000 pounds of payload to low Earth orbit (80 by 150 nautical miles) to provide an unmanned cargo delivery capability to the Space Station Freedom during its permanently manned phase.

The NLS 2 vehicle, which would employ a common vehicle "core" with the NLS 1, based on the space shuttle external tank, would provide a payload capability of 50,000 pounds to low Earth orbit to meet the needs of the DOD's heaviest payloads.

The NLS 3 vehicle would be capable of lifting 20,000 pounds to low Earth orbit using a single STME to meet the needs of the DOD and NASA medium class payloads. The NLS 3 design also had the potential to significantly enhance the cost and operational competitiveness of the US commercial launch industry in the international marketplace.

The increasing number of DOD and NASA medium class payloads, coupled with the commercial industry's need to meet the rising international competitive challenge, were significant factors that would influence the decision on the appropriate phasing of the various NLS configurations. All three launch vehicles would employ common avionics, electro-mechanical actuators, and the space transportation main engine (STME) -- the centerpiece of the NLS development effort.

NEW LAUNCH SYSTEM⁽⁵⁾

On April 16, 1991, the National Space Council directed NASA and the Department of Defense to jointly develop and jointly fund development of the New Launch System to meet civil and national space needs and to actively consider commercial space requirements.

The National Space Council set three goals for those it has charged with the New Launch System's development responsibility: greatly improve national launch capability; reduce operating costs; and improve reliability, responsiveness and mission performance.

The goal of the new New Launch System program was to develop a modular launch system which can support a range of medium- to heavy-lift requirements, facilitate evolutionary changes as requirements evolve into the 21st century, take maximum advantage of existing components to expedite initial launch capability and reduce development costs, and develop a system which, while being unmanned initially, could be man-rated in the future.

The National Space Council asked for a first flight of the New Launch System by the turn of the century. NASA and its Department of Defense partners were told to maintain flexibility for several schedule options, to identify key intermediate milestones in the development process, and to expect a final decision on continued development sometime in 1993.

Mission requirements fell into three broad categories: generic, Department of Defense/Air Force-specific, and NASA-specific.

In general, the New Launch System would reduce launch costs, improve operations, and evolve into a system that is more responsive and resilient than systems currently in use.

Specific military needs focus on follow-on missions as planned changes and/or improvements to Department of Defense/Air Force spacecraft occur, new military space initiatives arise, and activities related to Strategic Defense Initiative experiments and operations develop.

NASA's specific requirements were for a Space Station Freedom resupply vehicle, a vehicle to assist with the expansion of Space Station Freedom once permanent manned capability has been achieved, support for medium to large science missions, launching geostationary satellites and planetary probes, and supporting President George Bush's July 20, 1989, pledge to return America to the Moon to stay and land humans on Mars before 2019.

The New Launch System had eight program elements which are used to form two initial vehicle configurations: a medium payload-lifting vehicle, known as the 1.5 stage, and a heavy payload-lifting vehicle. Tankage for this core vehicle will be derived from the Space Shuttle's external tank. The Space Transportation Main Engine (STME), a new 600,000-pound thrust class liquid hydrogen- and liquid oxygen-fueled gas-generator engine, would be developed to supply the core vehicle's propulsion.

The medium-lift vehicle in the New Launch System would be capable of placing a 50,000-pound payload in an 80 by 150 nautical mile orbit. It would use the core vehicle but with six of the new liquid-fueled engines.

A smaller vehicle also was envisioned for later development in the New Launch System program. With a 20,000-pound payload, it would use one liquid-fueled engine, thus requiring new tankage, but would use other elements common to the core vehicle and would deliver a 20,000-pound payload to the same 80 by 150 nautical mile orbit.

The heavy-lift vehicle element of the system would consist of the core vehicle with four liquid-fueled engines and two Solid Rocket Boosters. It would be capable of delivering a 100,000-pound useful payload to rendezvous with Space Station Freedom 220 nautical miles above the Earth.

An upper stage for the system would be developed to boost payloads to a stationary, geosynchronous orbit 22,000 miles above the Earth. As regards a payload shroud, modifications are being considered to that currently in use on the Titan IV rocket.

The New Launch System would require development of a cargo transfer vehicle to move payloads, once they are in orbit, to dock with Space Station Freedom.

The final element of the system will be construction of ground support facilities. An STME Component Test Facility is already under construction at the Stennis Space Center on Mississippi's Gulf Coast. The Cape Canaveral Air Force Station would see modifications to launch pads 34 or 37, acquisition of a mobile launch platform, building of the core vehicle assembly and checkout facility, and construction of a cargo integration building and a vehicle integration building. NASA's Kennedy Space Center would also gain a mobile launch platform (to move its New Launch System vehicles to launch pads 39A and 39B which are already in existence), a payload encapsulation facility and a vehicle assembly building and launch pad facility.

The estimated cost of the New Launch System was in the $10.5 billion to $12 billion range, based on preliminary engineering definition and a six-week study effort. The single best cost estimate was being developed which would reflect the results of joint definition work begun in 1991, a six-month effort by Department of Defense and NASA program and budget personnel and support from the Defense Acquisition Board and NASA personnel.

A number of milestones were set for the program, including the first firing of the Space Transportation Main Engine by the end of 1996 and delivery of the first set of STME flight engines in 1999, the same year the common core pathfinder vehicle is to be delivered. Initial launch capability for the heavy-lift launch vehicle is expected in the year 2000, but this was not to be finalized until technical progress and mission requirements were reviewed in 1993. Planning for the launch support facilities was to be completed the following year with modifications to the pad 39 area at Kennedy Space Center to begin in 1996 and modifications and construction at Cape Canaveral Air Force Station to begin in 1997-98.

References

1. Maj Michael J. Muolo, Maj Richard A. Hand, Maj Bonnie Houchen and Maj Lou Larson, Space Handbook A War Fighter's Guide to Space -- Volume One, AU-18, Air University Air Command and Staff College, (Air University Press, Maxwell Air Force Base, Alabama, December 1993).

2. Gen John L. Piotrowski, "Military Space Launch: The Path to a More Responsive System (Part 1)," Aerospace & Defense Science, vol. 9, no. 7, July 1990, page 43.

3. William B. Scott, "ALS Cost, Efficiency to Depend Heavily on Process Improvements," Aviation Week & Space Technology, 23 October 1989, page 41.

4. Adapted from: Testimony by Lt. Gen. John E. Jaquish, principal deputy, assistant secretary of the Air Force (acquisition) and Maj. Gen. Donald G. Hard, director of space programs, assistant secretary of the Air Force (acquisition) to the House Committee on Appropriations, Subcommittee on Defense, in Washington, DC, 6 May 1992.

5. Adapted from: NASA Marshall Space Flight Center, "New Launch System," 29 August 1991.