The establishment and functions of the AFCRL balloon operations facility are discussed. The types of research work conducted by the facility are defined. The facilities which support the balloon programs are described. The free balloon and tethered balloon capabilities are analyzed

Danaher, T. J.

English

NASA Technical Reports Server

N75 12752PAPER 3.2
AIR FORCE CAMBRIDGE RESEARCH LABORATORIES BALLOON OPERATIONS
Thomas J. Danaher
Air Force Cambridge Research Laboratories
ABSTRACT
AFCRL scientific ballooning is unique in the Air Force and
provides the only Department of Defense in-house capability. A
general information base is provided to familiarize the reader with
the Air Force organization, research efforts, facilities and balloon
flight operations.
INTRODUCTION
The USAF Balloon Program is managed by the Aerospace Instrumentation
Laboratory, one of nine Air Force Cambridge Research Laboratories,
located at L. G. Hanscom Field, Bedford^ Massachusetts. The Aerospace
Instrumentation Laboratory is composed of a balloon group and a sounding
rocket group. The primary mission of the balloon group is to support
the research, development, test and evaluation and operational needs
of our sister laboratories in AFCRL and of other elements of the Air
Force. Our other objective is to extend the capabilities and versatility
of balloons as atmospheric platforms. To carry out this mix of research
and operational work, the balloon group of ninety-two people consists
of physicists, meteorologists, engineers, and operationally trained
personnel.
I will touch only briefly on our research efforts since the topic
of this paper is concerned with our balloon operations. The research
can be characterized by the following work efforts:
(1) Free Balloons - materials studies directed primarily
towards increasing the load-carrying and altitude capabilities of poly-
ethylene balloons.
(2) Tethered Balloons - development of improved tethered
balloon cables, improved balloon designs and materials, and studies
of balloon dynamics.
(3) Powered Balloons - advanced systems design, power source
studies and flight test of prototype models.
(4) Air Launched Balloons - studies of systems launched from
aircraft and rockets.
(5) Climatological studies - flight dispersion and operational
analyses for proposed programs.
(6) Instrumentation and Tracking - development of navigational
systems and command and control instrumentation.
Balloon flight operations conducted at our permanent launch sites
located at Holloman AFB, New Mexico and Chico, California utilize and
evaluate the research and development products of the balloon group.
Thus, there is a closed loop between theory, development, and applica-
tion, providing the setting wherein theory can be quickly tested and
future research needs readily identified.
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BALLOON FLIGHT OPERATIONS
As mentioned in the introduction, our mission is first to
support Air Force needs. We also provide balloon flight support
to other Dept. of Defense agencies and government organizations.
Within the latter category, for example, the AFCRL has acquired the
responsibility of providing support to the Atomic Energy Commission's
Ash Can project, for which about 30 flights per year are conducted.
Flights are made from New Mexico, California, Alaska and Panama.
The Panama and Alaskan series are conducted once a year. With the
impending retirement of the WB-57 aircraft, the Ash Can project will
be expanded to include additional air sampling flights within the
40,000 to 60,000 ft (1.2xl04 to 1.8xlO*m) altitude range.
Measurements are made of Carbon 14 and radioactive particulate
concentrations. After the samplers have performed their functions
the payloads are separated from the balloons and aerially recovered
by C-130 aircraft. We are working to extend the present capability
of snatching payloads of 450 Ibs (2.0xl03N) to loads on the order
of 700-1200 Ibs (3.1x103 to 5.4xl03N). In order to do this, a new
recovery parachute system is under development. We expect that
prototype systems will be tested this summer. The advantages of air
snatching the balloon payloads are obvious because terminations may
occur over water, jungles or the arctic tundra. Since we have been
involved in the Ash Can program, the aircrews have not failed to bring
a payload home.
NASA has frequently utilized AFCRL balloon flight support. The
Planetary Entry Parachute Program, PEPP, and the Balloon Launched
Decelerator Test Program, BLDT, for the Viking Program, were major
balloon programs conducted for NASA during the past few years. This
past year we concluded a balloon-borne laser flight series for NASA-
Goddard which provided data on the atmospheric effects on laser beams
transmitted from a balloon at 90,000 ft (2.7xl04m) to a receiver on
the ground.
In summary, in regard to whom balloon flight support is given,
first priority is to the Air Force, followed by organizations which
have programs from which the Air Force may derive benefit. For
example, the NASA PEPP and BLDT programs resulted in the development
of new, heavy-payload balloon capabilities which can be directly
utilized in Air Force systems testing.
The Air Force has on occasion been accused of being the prime
polluter of the lower stratosphere and of doing little to determine
the effects on air quality of its aircraft operating at these altitudes.
In the balloon sampling program the Air Force is presently doing some-
thing about this problem. In the next few years the balloon group and
other AFCRL scientists will be engaged in stratospheric pollution
research, building on the results of the recent CIAP, Climatic Impact
Assessment Program. In particular, we will be conducting balloon flights
for AFCRL's Aeronomy Laboratory to obtain data on chemical reactions
resulting from jet aircraft emissions in the lower stratosphere.
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FACILITIES
Permanent AFCRL balloon launch facilities are located at
Holloman AFB, New Mexico and at Chico, California. Both locations
also have a remote operations capability for performing fligiits
wherever a need may exist. The balloon launch facility at Holloman
AFB has access to the use of precision radar, optical instrumentation,
telemetry, and restricted airspace on the White Sands Missile Range.
Nuclear blast simulations, high altitude prototype parachute tests,
hardware evaluation, high altitude tethered balloon operations-any
test involving free-fall can be conducted by the Holloman facility.
Each launch site has a completely equipped and staffed weather
station, machine shop, instrumentation laboratory, parachute shop,
and a small environmental test chamber. The Holloman facility has
the use of an environmental test facility with a working volume
of 8x8x11 ft (2.4x2.4x3.4m), an altitude range from sea level to
225,000 ft (6.86xl04m), and a temperature range of minus 100°F to
plus 200°F (minus 73.3°C to 93.3°C).
TETHERED BALLOON FACILITY
AFCRL first became involved in tethered balloon operations when
it provided support to NASA's testing of the Surveyor lunar lander.
Subsequently, the immediate and potential capabilities of tethered
balloons became better appreciated and it became obvious that a
permanent facility was essential for these operations. Consequently,
Fair Site was established on White Sands Missile Range solely for the
purpose of supporting tethered balloon operations. The criteria for the
selection of this site were that it should:
(1) be capable of routinely handling payloads of 500 pounds
(2.2xlQ3N) or more to altitudes in excess of 10,000 feet (3.1xlQ3m)
above ground.
(2) be unencumbered by other programs.
(3) be in a restricted air space area to permit flight
durations of hours to weeks, and
(4) be suitable for future expansion, to accommodate develop
ment testing and operations of tethered systems of much greater payload
altitude capabilities.
Fair Site is located in the northwest corner of restricted area,
R-567-B, on the White Sands Missile Range. It is approximately 70 land
miles (I.lxl05m) from Holloman AFB. Here, there is no restriction upon
the flight altitude of tethered balloons. Meteorological conditions
have been investigated fully, and the climatology indicates a good
year-round flight capability.
The site has the advantage of a fully instrumented range to provide
data essential for interpreting the results of many scientific experi-
ments flown on tethered balloon systems. Position data for our tethered
balloon flights can be obtained using either FPS-16 radars or cinetheod-
olites or both. If radar is used, a position display can be set up at
the Balloon Control Center at Holloman AFB or at some Range Control
Station. Velocities, accelerations and balloon altitude data can be
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obtained from both cinetheodolites and on-board instrumentation.
Data reduction is provided through WSMR. In addition to the
cinetheodolites and radars, facilities for receiving a wide variety
of telemetered data are available.
The heart of the tethered balloon facility is the permanently
fixed winch which has the following capabilities:
(1) Line pull capabilities of 30,000 pounds (1.3xl()EN.)
maximum at a maximum speed of 200 feet (61 m.) per minute;
(2) Line pull capabilities of 6,000 pounds (2.7xl04N.) at
line speeds of 1,000 feet (3xl02m.) per minute;
(3) Variable speed control in each of the above modes;
(4) Fail-safe brake system;
(5) Interchangeable sheave and capstan shoes;
(6) Drum capacity to 30,000 feet (9.1xl03m.) of ^-inch
(1.3xlO~2m.) diameter line;
(7) The capability of accommodating line sizes from 3/8-inch
through 3/4-inch diameter (9.5xlO~3m through 1.9xlO-3m.).
(8) Level wind system capable of storing 3/8-inch through
3/4-inch diameter (9.5xlO~3m. through 1.9xlO~2m.) line sizes uniformly
on the winch drum, and adjustable for these line sizes with 1/16-inch
(1.6xlO~3m.) variation in diameter.
(9) Instrumentation consists of a line-load measuring device,
line-footage counting device, line-speed and direction measuring device.
(10) Other instruments include those items necessary to monitor
the operation of the power source and the hydraulic drive system.
FILMS OF AFCRL BALLOON OPERATIONS
In closing, I will show a short film which gives a general view
of some of the equipment we use in our balloon operations and the
retrieval of an Ash Can payload by C-130 aircraft over Panama.
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DISCUSSION SUMMARY - PAPER 3.2
In answer to questions about expected cost and performance of a tethered
balloon operating at 60,000 ft, the development cost was estimated at $750,000.
The French already have flown a 250-pound tethered balloon this high. The
possibility of flying a 500-pound device at 90,000 ft was considered good if
money were available.
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PAPER 3.3
SPECIAL PANEL DISCUSSION ON LONG DURATION BALLOONING
DISCUSSION SUMMARY - PAPER 3.3
Panelists: Dr. Ricker and Dr. Lewin of M.I.T., Mr. Pavey, Mr. Snider
and Mr. Shipley of NCAR.
During the panel discussion on long duration balloon flights several
points were covered. These points included the importance, effectiveness and
some details of such systems, a proposed NCAR program to develop required
capabilities and finally the current funding situation.
Two types of long duration balloon systems were considered. One approach
uses a zero pressure balloon launched in Europe and recovered after 5-8 days
in the United States. The second system would involve launching a superpres-
sure balloon from Australia that would circumnavigate the globe during flights
lasting several months.
It was stressed that development of these systems is the important next
step in scientific ballooning. The basic advantage of course, is the increased
observing time afforded by these long flights. Satellites and balloon-borne
instruments were compared to illustrate this time advantage. The sensitivity
in many investigations improves as the square root of the observing time avail-
able. Therefore, long duration balloon flights are perhaps 10-20 times more
sensitive than one day flights, but satellites are perhaps only twice as sen-
sitive as long duration balloon flights. It was estimated that satellites cost
one hundred times more per pound than balloon-borne instruments. Therefore,
balloon-borne investigations are more cost effective.
During discussion it was pointed out that although the trans-atlantic
flights are not as long as the flights around the southern globe there are com-
pensating factors. The most important is the much larger payload capability
of the zero pressure trans-atlantic flight. This payload makes possible larger
instrument apertures. Since sensitivity depends on aperture, this compensates
for the shorter flight duration.
Other advantages of long duration balloon flights were noted. Opportuni-
ties to fly instruments on balloons are far more numerous than opportunities
for satellite flights. The lead time for balloon-borne investigations is
short. Therefore, research concepts can be pursued at a satisfactorily rapid
pace. In addition, instrumentation changes required to meet new requirements
are possible through most of a balloon flight program.
There was some discussion concerned with dangers to air traffic. Since
these balloons float well above commercial air corridors, the only times of
concern are during launch and recovery. Safety measures to cover these
periods have been well developed during conventional balloon programs. Further-
more most of the long duration flights are planned for far south latitudes
where air traffic is very light.
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NCAR summarized a proposal to the National Science Foundation covering
the development of a long duration balloon flight program. The instrument con-
sidered would weigh 400-500 pounds and float at 130,000 feet. During discus-
sion various estimates were made of the fraction of this weight available for
the scientific instrumentation. These estimates varied from 80-300 pounds.
It was felt that this size payload represented a useful and practical first
step. The program would cover a two year period and would include both balloon
development and test flights. As part of the balloon development, NCAR will
analyze the various aspects of the dynamics of mylar balloons. Other balloon
materials and balloons will be developed by U.S. companies under contract.
There are five (5) test flights included in the program. Three (3) will be in
the United States and two (2) in Australia.
Estimates of the costs involved in future research flights were presented.
These estimates were based on a projected program including fifteen (15) flights
per year. Superpressure. balloons suitable for long duration flights will cost
about $50,000 each. Operations costs including launch, tracking, recovery,
and operation of four (4) ground stations were estimated at $75,000 for the
fifteen (15) flights. Cost of the flight control electronics was not included
since it is expected to be recovered.
Some of the general aspects of the present funding situation were dis-
cussed. NASA provides some support for research and development, but not
enough to fund the two (2) year development program. Most of the NASA funding
is for operations costs involved in current research flights.
For this development project to proceed it must have National Science
Foundation funding. There has been an endorsement of the project by the
National Academy of Sciences. The problem is that the required funding is in
competition with other research programs and with current balloon operations
funding.
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