Long Duration Balloon (LDB)
Missions that use either existing balloons in locations where the balloon is in constant daylight, or will use a super pressure balloon design that is intended to
achieve durations of 100 days or longer at mid-latitudes. The long-duration flights
in constant daylight are currently flown from Antarctica and Sweden.
Modulus of Elasticity
The ratio of stress to strain. The Young’s modulus is this ratio throughout the linear portion of a stress-strain curve. The "initial modulus" is a relation of stress to
strain near zero stress; the "secant modulus" is the stress-strain ratio at a point on
the stress-strain curve.
Payload
The science instrument that the balloon lifts to the stratosphere; it could be a telescope or other instrument. Balloon payloads study the origins of the universe,
cosmic rays, supernovae, black holes, dark matter, dark energy and other space
phenomena. Balloons can also support in situ measurements for Earth and planetary science. Since the payloads are typically hung under the balloon, the size and
dimensions are not too constrained. That is one of the advantages of using balloons for scientific investigations. The science payload can be as heavy as 6,000
lb.
Piggyback payload
Typically small instruments that fly on another balloon flight. They are typically
small innovative instruments and do not require all of the support a full scientific
instrument payload may need. They can be added to an existing flight with little
added weight or power requirements. It is an advantage that balloon flights can
accommodate these small cutting-edge technology development instruments and
give them turnaround flight opportunities.
Permeability
The volume rate of gas transfer through a material per area per pressure
differential.
Poisson’s Ratio
The negative ratio of transverse strain to axial strain within the elastic limit of the
material.
340 Glossary and Terminology
Missions that use either existing balloons in locations where the balloon is in constant daylight, or will use a super pressure balloon design that is intended to
achieve durations of 100 days or longer at mid-latitudes. The long-duration flights
in constant daylight are currently flown from Antarctica and Sweden.
Modulus of Elasticity
The ratio of stress to strain. The Young’s modulus is this ratio throughout the linear portion of a stress-strain curve. The "initial modulus" is a relation of stress to
strain near zero stress; the "secant modulus" is the stress-strain ratio at a point on
the stress-strain curve.
Payload
The science instrument that the balloon lifts to the stratosphere; it could be a telescope or other instrument. Balloon payloads study the origins of the universe,
cosmic rays, supernovae, black holes, dark matter, dark energy and other space
phenomena. Balloons can also support in situ measurements for Earth and planetary science. Since the payloads are typically hung under the balloon, the size and
dimensions are not too constrained. That is one of the advantages of using balloons for scientific investigations. The science payload can be as heavy as 6,000
lb.
Piggyback payload
Typically small instruments that fly on another balloon flight. They are typically
small innovative instruments and do not require all of the support a full scientific
instrument payload may need. They can be added to an existing flight with little
added weight or power requirements. It is an advantage that balloon flights can
accommodate these small cutting-edge technology development instruments and
give them turnaround flight opportunities.
Permeability
The volume rate of gas transfer through a material per area per pressure
differential.
Poisson’s Ratio
The negative ratio of transverse strain to axial strain within the elastic limit of the
material.
340 Glossary and Terminology