NRL Center for Space Technology Reaches Century Mark in Orbiting Spacecraft LaunchesBy Daniel Parry | October 2, 2011
Celebrating the launch of the 100th satellite into orbit with the launch of TacSat IV, Sept. 27, the U.S. Naval Research Laboratory's Naval Center for Space Technology commemorates a pioneering and fruitful space-based research program that got its start some 65 years earlier.
After World War II, captured German V-2 rockets were brought to the U.S. Army's White Sands Missile Range, N.M., where they were reassembled for research and experimentation by government agencies and universities as a means for sending scientific instruments above the bulk of the earth's atmosphere, which absorbs ultraviolet (UV) radiation.The Army set to work with V-2 rockets at the White Sands Missile Range in 1946 and scientific users were invited to fill the space of the 2000-pound warhead with instruments. E.O. Hulbert at the NRL Optics Division jumped at the chance.
In 1946, the U.S. Naval Research Laboratory (NRL) in Washington D.C., was invited to participate in the Army's V-2 rocket program. As an established group ready to carry out upper atmospheric research, the newly formed NRL Rocket Sonde Branch, led by physicist Ernst Krause, elicited research physicist Richard Tousey, head of the Instruments Branch, to design a rugged, V-2 capable, solar spectrograph to study the nature of atmospheric absorption, and to examine the ultraviolet portion of the solar spectrum.
The first launch occurred June 28 in an effort to place an ultraviolet spectrograph over 160 km [nearly 100 miles] above the desert floor to record the intensity of high-energy radiation emitted from the Sun. Although this spectrograph tape was never recovered, the Laboratory became the prime agency for developing the technology and carrying-out the missions of the V-2 rocket-sounding program.
Between 1946 and 1951, eighty experiments were performed providing new and valuable information about the nature of Earth's upper atmosphere and ionosphere. The first being the successful launch, Oct. 10, 1946, delivering the first recorded solar spectrum of the Sun from above Earth's atmosphere.
NRL also directed the development of a new sounding rocket called Viking. From 1949 to 1954, 12 Viking rockets were launched, providing NRL the first measurements of temperature, pressure, and winds in the upper atmosphere and electron density in the ionosphere, and record of the ultraviolet spectra of the Sun. On October 5, 1954, a Viking rocket carrying a movie camera captured the first high-altitude images of a tropical storm over the Gulf of Mexico, sparking the interest of the U.S. Weather Bureau and the future of high-altitude weather reconnaissance.
Beginning in 1957, NRL turned to newly developed Nike rockets having several different second-stage rockets, to study the Sun during the International Geophysical Year, July 1957 to December 1958. During these studies, NRL scientists recorded the first measurements of ultraviolet and X-ray emissions during a solar flare.Roger Easton (left) supervising the placement of the Vanguard-1 satellite atop the Viking launch vehicle.
Between 1955 and 1959, NRL conducted the first American satellite program named Project Vanguard, which became the prototype for much of what became the U.S. space program. On March 17, 1958, the Vanguard I satellite was successfully launched into Earth orbit. Although communication with the satellite was lost in 1964, Vanguard I was the second artificial satellite successfully placed in Earth orbit by the United States and remains the oldest man-made satellite in orbit today and the first to use solar cells. The first U.S. satellite, Explorer I, was launched February 1958 by the U.S. Army, but similar to the Soviet satellites Sputnik I and II, Explorer I has long since fallen out of orbit.
When the National Aeronautics and Space Administration (NASA) was established on July 29, 1958, the NRL Vanguard group, comprised of approximately 200 scientists and engineers, became the core of its spaceflight activities. The group remained housed at NRL until the new facilities at the Goddard Space Flight Center at Beltsville, Md., became available in September 1960.
The exodus created by the newly formed space agency did not however signal an end to NRL satellite and space-based research. Through the advocacy of Martin Votaw, who believed the Navy had an important role to play in space, a small contingent of remaining NRL rocket scientists and technicians regrouped to form the Satellite Techniques Branch headed by Votaw.
The Satellite Techniques Branch staff concentrated on the engineering hardware of what was referred to as the satellite bus and was responsible for the structure, power supply, command, telemetry and the coordination of the satellite, along with its interface with the booster. Additionally, they handled any special circuitry needed to support the satellite payload.Mosaic Compilation - Taken from a Viking rocket from an altitude of 100 miles, NRL scientists capture the first image of a tropical storm (bottom-right), Oct. 1954, swirling in the Gulf of Mexico.
The group's first post-Vanguard success was in June 1960 with the launch of the world's first orbiting astronomical observatory to study the Sun's effects on the Earth. Piggybacked on the Transit IIA satellite, a larger U.S. Navy satellite, the first solar radiation satellite, SOLRAD-I, was equipped with both X-ray and Lyman-alpha sensors. Determining that radio 'fade-outs' were caused by solar X-ray emissions, SOLRAD-I had an immediate scientific impact — verifying a theory held by NRL research physicist, Dr. Herbert Friedman of the direct relationship between solar X-ray variability and the strength of the Earth's ionosphere.
Shrouded in secrecy for nearly 40 years, SOLRAD-I also shared the first U.S. Navy electronic intelligence (ELINT) instrumentation for Cold War reconnaissance. The project was originally called Tattletale, but was renamed the Galactic Radiation and Background satellite system, or GRAB, to conceal its purpose from the Soviets. Having successfully developed and installed radar detectors on submarine periscopes, NRL scientist Reid Meyo of the Countermeasures Branch developed the idea that the success of his submarine periscope antenna could function equally well in orbit aboard a satellite.NCST designed and built the GRAB satellite (shown mounted atop the Transit IIA satellite) and a network of overseas data collection facilities. The launch was approved by President Eisenhower in May 1960, just four days after a CIA U-2 aircraft was lost on a reconnaissance mission over Soviet territory.
The GRAB receivers were used clandestinely to catalogue the waveforms and pulse repetition frequencies of Soviet air defense radars. The data was recorded on magnetic tape and couriered back to the NRL, then evaluated, duplicated, and forwarded to the National Security Agency (NSA) at Fort George G. Meade in Maryland and the Strategic Air Command (SAC) at Offutt Air Force Base, Omaha, Neb., for analysis.
Subsequent SOLRAD satellites collected solar X-ray and ultraviolet data during numerous intervals in the years 1960 to 1973, with instrumentation and quality of data improving in each succeeding spacecraft in the SOLRAD series.
Besides measuring solar radiation and calibrating satellite tracking systems and a handful of classified deployments, NRL-made satellites have harvested massive amounts of basic data that became crucial for subsequent satellite design and for overall thinking about how the space environment can further the Navy's mission and capabilities, states Ivan Amato, author, Pushing the Horizon.
One of the more notable of these capabilities comes from the launch of the TIMATION satellite in 1967. A vision of NRL research physicist, Roger Easton, TIMATION, short for time-navigation, proved that a system using a passive ranging technique, combined with highly accurate [atomic] clocks, could provide the basis for a new and revolutionary navigation system with three-dimensional coverage (longitude, latitude, and altitude) around the globe.
Through the development and launch of three additional experimental satellites: TIMATION II in 1969; Navigation Technology Satellite (NTS-I) in 1974; and the first satellite to fly a cesium atomic frequency standard in a 12-hour GPS orbit, NTS-2, in1977, Easton had proved the practicality and unprecedented accuracy of satellite-based atomic clocks and laid the foundation for modern day global positioning systems.
By the mid-1980s, NRL had been involved in the launch of nearly 80 satellites. In recognition of this sustained record of excellence, the U.S. Navy in 1986 formalized the Laboratory's status as its lead laboratory in space technology by officially inaugurating the Naval Center for Space Technology (NCST) at NRL.NRL'S TIMATION III satellite was redesignated the Navigation Technology Satellite-I (NTS-1) and was launched in the summer of 1974 in connection with the NAVSTAR effort. NTS-1 had two rubidium-vapor frequency standards clocks, while the earlier TIMATION satellites had carried selected high-performance crystal oscillator clocks.
Leading the space program at NRL since 1964, and encompassing more than five decades of experience in the development, deployment and operation of satellites critical to the nation's defense and intelligence gathering capabilities, Peter Wilhelm was named director of NCST in October 1986.
With the successful launch of several more satellites — the final satellite in the Living Plume Shield series (LIPS-III) in 1987 to test space-based power sources; the Low-Power Atmospheric Compensation Experiment (LACE) in 1990 with a total of 210 sensors capable of characterizing ground-based laser beams with continuous wave or pulsed emission in the visible, ultraviolet, and infrared bands; and the Satellite Launch Dispenser Communications System (SLDCOM) series in the early 1990s to test bent pipe UHF satellite communications — NCST was tasked to turn its attention toward deep-space exploration and NRL's first lunar satellite.
Formally named the Deep Space Program Science Experiment, the project was soon dubbed Clementine due to its exhaustible mission. Launched on January 25, 1994, Clementine was built to test lightweight miniature sensors and advanced spacecraft. Extensively mapping the moon between February 26 and April 22, Clementine delivered nearly two million digital images of the lunar surface back to the ground network located in Alexandria, Va.
When scientists reviewed the data, they made the major scientific discovery of possible ice within some of the moon's craters. This accomplishment was cited by President Bill Clinton as one of the major national achievements in space. This discovery was later confirmed by the NASA Lunar Reconnaissance Orbiter (LRO) in 2009.
In the late 1990s and early into the following decade, the NCST hosted Project Starshine (Student Tracked Atmospheric Research satellites), a mentoring program that provided students with insight and understanding into the satellite development process, orbital dynamics and scientific methods. Over the course of the program, three small, optically reflective spherical STARSHINE student satellites were launched and tracked by the students who were able to collect data on the density of the Earth's atmosphere. The data, shared via the Internet, was also used by NRL scientists to measure the effects of solar extreme ultraviolet radiation on satellite orbital decay.TacSat-4 is readied for encapsulation into the nose fairing (background) of an Orbital Sciences Minotaur-IV+ launch vehicle. The satellite launched from Alaska Aerospace Corporation's Kodiak Launch Complex, Kodiak Alaska, Sept. 27, 2011.
In 2003, under the sponsorship of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Integrated Program Office (IPO), the NRL-developed WindSat satellite was launched January 6 to provide important meteorological information on ocean surface wind speed and direction delivering, for the first time, real-time, tactical information to Naval surface units. WindSat's continued measurements over the ocean are also used operationally as input to numerical weather prediction models of the U.S. Navy, National Oceanic and Atmospheric Administration (NOAA) and the United Kingdom Met Office.
Embarking on new, cost-effective, compact, quick-launch space-based platforms, two NCST designed and built experimental nano-satellites, NRL's 98th and 99th orbiting spacecraft, were launched in December 2010 and successfully contacted on their first orbit. Known as the CubeSat Experiment (QbX), satellites QbX1 and QbX2 were deployed to evaluate nano-satellites as a platform for experimentation and technology development. The QbX vehicles, positioned in a low-Earth-orbit and controlled using a novel Space Dart mode, remained in orbit for only 30 days before succumbing to the effects of atmospheric drag.
Today, the NCST continues to play an important role in space. With the launch of the 100th man-made satellite to Earth orbit, September 2011, TacSat-4 will help define future options for launching one or more, smaller, highly elliptical orbit (HEO) satellites and test advances in several technologies and satellite communication (SATCOM) techniques. In addition to demonstrating the potential benefits of a future, combined HEO and geosynchronous orbit constellation, TacSat-4's primary objective is to allow forward deployed troops to communicate on the move from obscured regions using existing hand-held radios and without the need to stop and point an antenna towards the satellite.
The NCST is also developing technology, known as electro dynamic tethers, that seek to solve the increasingly urgent issue of orbital space debris, a mission vital to the protection of current space-based assets and future satellite placement.
The Naval Center for Space Technology Directorate (Code 8000) remains the U.S. Navy's lead laboratory in space technology research and applications. Dedicated to preserving and enhancing a strong space technology base and providing expert assistance in the development and acquisition of space systems for naval missions, the activities of NCST extend from basic and applied research through advanced development in all areas of interest to the Navy space program.
Operating under the NCST Directorate is the Space Systems Development Department (Code 8100), responsible for space and ground support systems research and development, and the Spacecraft Engineering Department (Code 8200), functioning as the program manager for Navy space programs, providing systems engineering and technical direction and in-house satellite development.