MAR
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Mid Air Retrieval
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MAR Background
Mid-Air Retrieval (MAR) is a technique
for retrieving a payload descending under a parachute using an aircraft so
that it can be returned to a designated location without impact damage.
In the 60's and 70's film canisters from reconnaissance satellite were routinely
recovered using MAR. The last program to use MAR extensively was
ALCM, with MAR operations out of Hill AFB. Reliability was approximately
95 percent. Other than one recovery helicopter that was lost during
Navy operations, the safety record of MAR operations was excellent.
In 1992 Vertigo demonstrated tandem
parafoil MAR under contract to Teledyne Ryan Aeronautical and the U.S. Navy.
The program was extremely successful and showed substantial advantages over
previous nongliding systems.
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Parachute hooked on drag line
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Parachute and payload towed behind helicopter
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Close up view of parachute and payload
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Advantages of a MAR system for recovery
of the Genesis vehicle compared to a nongliding descent to ground impact
are:
- Lower installed recovery system weight.
- Elimination of the pyrotechnic ground release mechanism.
- Avoidance of ground impact.
The principle limitation of the system is
that, at the current state of development, MAR operations are limited to daytime
visual meteorological conditions (VMC).
The goal of the proposed system is
0.99 reliability of engagement per helicopter pass. The ability to
make multiple passes and/or to use multiple helicopters will make the operation
exceedingly reliable. This phase B work plan will demonstrate feasibility
and reliable operation, but will not generate enough operational data to
prove the reliability goal. This will be addressed in later phases.
System Description
The proposed recovery system is a single
stage, slider-reefed parafoil, deployed by a mortar-deployed pilot chute.
A system of load lines is added to the normal suspension lines for the purpose
of MAR hook engagement and captive carriage loads.
The MAR helicopter subsystem consists
of a constant tension winch, AAE model 15, a single pole that pivots off of
the pilot-side landing skid, a hook and release mechanism, and rigging to
guide the retrieval cable out the door of the helicopter.
Historically, MAR systems have used
separate main and target parachutes, with the main parachute being cut away
when the engagement network in the target parachute is put under tension
upon engagement. The proposed system uses a single main parachute
that contains the load network. The main parachute is of a size that
is small enough not to interfere with towing the payload back to the
landing pad, yet large enough to present a good engagement target.
The parafoil size will determine gliding
airspeed, which will be chosen based on experience for best MAR safety and
reliability. The descent rate determines the number of engagement
passes possible from intercept altitude to impact and should be minimized.
Safety is of primary concern during
testing. If the load needs to be released, either the manual cargo
release from the helicopter’s external cargo hook can be activated, or an
additional pyrotechnic cutter installed on the load line below the cargo
hook can be activated by either the pilot or the load master. This will
release the entire parafoil and dummy payload assembly. Additionally, pre-catch
dynamic load testing will be conducted by mounting the winch pallet MAR system
on a truck and picking up an equivalent mass. This functional test of the
MAR system will provide an end to end system checkout. This test will
greatly reduce, if not eliminate the possibility of a tension failure of
the payload pickup line during flight operations. A tension failure
of the pickup line could present a safety concern.
A number of suitable helicopters are
available. The preferred helicopter for this phase is the Aerospatiale
AS 350B Ecureuil. Safety, cost and cabin configuration are considered in
making this selection.
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Aerospatiale AS 350B Ecureuil
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Interior view with MAR winch in place
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| System Requirements Summary |
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Recovery Weight
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500 lb.
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Deployment q
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25 psf
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Peak load
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NTE 30 g
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Material temperature
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NTE 100C during mission
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Deployment altitude
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20,000 ft
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Recovery site
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4,200 ft msl
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Maximum use is made of off-the-shelf equipment,
including production tandem size parafoils (used parafoils can be used for
bare pole and tow tests), and a GFE All American Engineering model 15 constant
tension winch. The hook and pole will be newly fabricated. The winch
system and all special helicopter equipment will be palletized for easy
installation and removal from the helicopter.
All deployment will be nonpyrotechnic
during Phase B. We will use a static line assisted pilot chute for deployment
of the parafoil. The design will be compatible with pyrotechnic deployment
if necessary in future phases.
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