A zero-pressure balloon with BOBCAT aboard was launched from Fort Sumner,
NM on August 22, 2019 as flight 696N. Shortly prior to the balloon reaching its
float altitude, the team pumped liquid nitrogen to pre-cool the test dewar. At the
float altitude they remotely commanded the transfer of 30 liters of liquid helium
to cool the container to the desired temperature. Since nitrogen flash freezes and
helium becomes superfluid at certain pressures (that would impair the ability of
the dewar to chill to the desired temperature) Kogut and his team also needed to
show that the transfer could occur in a near-vacuum.
This flight represented the first remote transfer of either liquid nitrogen or liquid helium at float altitudes, and demonstrated that potential problems related to
the transfer in this environment can be mitigated. The next engineering test will be
to transfer the cryogenic fluids into the ultra-lightweight test dewar now being
built by Goddard engineers. Its stainless-steel walls are just slightly thicker than a
beer can. The goal is to compare its performance to the standard, much heavier
dewar that was flown on the initial test.
Although GSFC can demonstrate ultra-lightweight dewars, it does not have the
manufacturing facilities to fabricate a dewar of sufficient size to accommodate a
large aperture cold telescope. As a result, NASA has awarded a Small Business
Innovation Research grant to the Quest Thermal Group LLC, a Colorado-based
company which specializes in the development of advanced thermal-insulation
systems. Their job will be to develop manufacturing techniques for a 3 m (10 ft)
or larger dewar. Kogut believes this effort will eliminate the concerns about the
technological maturity of flying large aperture telescopes on balloons.
For a presentation by Dr. Alan J. Kogut on the BOBCAT mission and technology,
go to:
https://drive.google.com/file/d/1uwDwgFgdzJ9xqCwrg_lWhJlkdWrmmCuj/view
7.4.3 Low Density Supersonic Decelerator (LDSD)
As NASA plans ambitious new robotic missions to Mars and sets the groundwork
for even more complex human science expeditions to come, the spacecraft needed
to land safely necessarily become bigger to deliver the heavy payloads required to
perform extended stays on the Martian surface.
The technology for decelerating from the high speed of atmospheric entry to
the final stages of landing on Mars dates back to the NASA Viking Program, when
two landers touched down on Mars in 1976. The basic Viking parachute design
has been used ever since, and was successfully used again in 2012 to deliver the
Curiosity rover.
NASA is seeking to use atmospheric drag as a solution, saving rocket engines
and fuel for final maneuvers and landing procedures. The heavier planetary
7.4 Instrument and Technology Development 161
NM on August 22, 2019 as flight 696N. Shortly prior to the balloon reaching its
float altitude, the team pumped liquid nitrogen to pre-cool the test dewar. At the
float altitude they remotely commanded the transfer of 30 liters of liquid helium
to cool the container to the desired temperature. Since nitrogen flash freezes and
helium becomes superfluid at certain pressures (that would impair the ability of
the dewar to chill to the desired temperature) Kogut and his team also needed to
show that the transfer could occur in a near-vacuum.
This flight represented the first remote transfer of either liquid nitrogen or liquid helium at float altitudes, and demonstrated that potential problems related to
the transfer in this environment can be mitigated. The next engineering test will be
to transfer the cryogenic fluids into the ultra-lightweight test dewar now being
built by Goddard engineers. Its stainless-steel walls are just slightly thicker than a
beer can. The goal is to compare its performance to the standard, much heavier
dewar that was flown on the initial test.
Although GSFC can demonstrate ultra-lightweight dewars, it does not have the
manufacturing facilities to fabricate a dewar of sufficient size to accommodate a
large aperture cold telescope. As a result, NASA has awarded a Small Business
Innovation Research grant to the Quest Thermal Group LLC, a Colorado-based
company which specializes in the development of advanced thermal-insulation
systems. Their job will be to develop manufacturing techniques for a 3 m (10 ft)
or larger dewar. Kogut believes this effort will eliminate the concerns about the
technological maturity of flying large aperture telescopes on balloons.
For a presentation by Dr. Alan J. Kogut on the BOBCAT mission and technology,
go to:
https://drive.google.com/file/d/1uwDwgFgdzJ9xqCwrg_lWhJlkdWrmmCuj/view
7.4.3 Low Density Supersonic Decelerator (LDSD)
As NASA plans ambitious new robotic missions to Mars and sets the groundwork
for even more complex human science expeditions to come, the spacecraft needed
to land safely necessarily become bigger to deliver the heavy payloads required to
perform extended stays on the Martian surface.
The technology for decelerating from the high speed of atmospheric entry to
the final stages of landing on Mars dates back to the NASA Viking Program, when
two landers touched down on Mars in 1976. The basic Viking parachute design
has been used ever since, and was successfully used again in 2012 to deliver the
Curiosity rover.
NASA is seeking to use atmospheric drag as a solution, saving rocket engines
and fuel for final maneuvers and landing procedures. The heavier planetary
7.4 Instrument and Technology Development 161