The most ambitious use of stratospheric Lighter Than Air (LTA) vehicles in the
 near-space regime is in the area of
station keeping airships.

These vehicles will have the ability to
be propelled against the wind in order to maintain persistence in a single area
for the duration of the mission.
 

The requirements of such a mission
are highly complex and inter-
dependent.  Theoretical trade
studies have shown the
potential payload for such
vehicles is on the
order of three tons.

Aerostar’s approach to this
engineering challenge is to develop
small technology demonstrators
that will allow the development
of operational mastery before
progressing to large vehicles.
This approach was outlined in the
Applications of Scientific Ballooning
Technology To High Altitude Airships
paper presented at AIAA in 2003.
 

In 2005 Aerostar teamed with
Southwest Research Institute to develop
the HiSentinel airship.

The HiSentinel carried a 60 lb payload
and telemetry pod to 74,000 ft and
achieved powered flight for 1.5 hours
during a five hour flight.

The historic flight saw the largest
stratospheric airship ever to achieve
powered flight in the stratosphere and
only the second stratospheric
airship to do so.

 

Engineered to carry a small payload to
70,000 ft, Sounder was designed for
 a flaccid launch with disposable hull.

Designed to climb in a vertical position,
the balloon was filled with a bubble of
helium sufficient to completely
inflate envelope at float altitude.

As the balloon reaches a fully inflated
state, the balloon naturally tips from
a vertical position to a horizontal
position for flight.

During that successful flight it was
discovered the line had become
entangled with the propeller
preventing powered flight from
being achieved.

Aerostar's parent company Raven
Industries is the only company to
successfully build a stratospheric
airship which achieved powered flight
 in the stratosphere prior to the
success of the HiSentinel Airship flight.

In 1969, under the High Platform II
project, Raven built and flew a small
airship which achieved powered flight
at 70,000 feet for two hours with a
five pound telemetry
and propulsion payload.
 

The most mature near space
technology available today
is the free-floating balloon platform.

These balloons are routinely
used for scientific applications,
and could readily be applied to
high altitude communications
relays or observations platforms.

In November of 2005, Aerostar
provided engineering support
and this type of balloon for
the United States Navy's
HAAREX test series.

 

Each balloon carried a 100 lb
communications relay system to an
altitude of 67,000 ft.  A total of fourteen
flights were conducted.  The flights
proved a standard UHF radio could be
used to communicate with units up to
250 miles away using the balloon
mounted equipment as a repeater.

This increased the operational range of the
radios by more than ten times.  Further development of the system includes miniaturization of the electronics and
development of a guided
parachute recovery system.

 Click on the image to see a clip of the launch of the HAAREX Balloon