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Файл:Антарктида (3 сем, мага) / MEPhI_LDB_talk_7_09_2023
.pdf
Long Duration
Balloon Astrophysics in
Antarctica
Alexander Malinin
MEPhI, Moscow, 7 September, 2023
Why balloons? Why in Antarctica?
Stratospheric balloons are historically very successful and
l
efficient scientific platforms to access near open space
environment (as high as up to ~1 mbar of residual atmosphere).
l
The requirements to the payload are mild compared to the
satellit e platf o rms (no vibrations, no dynamic rigidity
requirements to withstand the rocket launch stresses).
The austral summer in Antarctica provides 3 month long
l
continuous sun light for the solar PV-panels. No heavy batteries
are required.
Stratospheric balloon achieves a longest flight duration when
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launched in polar regions due to the helium thermal stability.
7th September 2023 LDB Astrophysics in Antarctica 2
History of scientific ballooning
Discovery of Cosmic Rays
Variation of ionization with altitude.
Left panel: final ascent by Hess (1912),
carrying two ion chambers. Right panel:
ascents by Kolhörster (1913, 1914).
7th September 2023 LDB Astrophysics in Antarctica 3
Long Duration Balloons
Why LDB? Some numbers:
7th September 2023 LDB Astrophysics in Antarctica 4
Highest LDB balloon flight
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In 2002, August 25, Low Energy Electrons (LEE) experiment flew on the
largest balloon ever successfully launched (60 x106 ft3 or 1.7 x 106 m3) reaching an
altitude of 48.8 km or 90 Pa (161 000 ft or 0.9 mbar). Reduced background and low
atmospheric attenuation allowed a measurement of low energy primary electrons
(during geomagnetic night) inaccessible at greater depths.
LEE at NASA CSBF, Texas
7th September 2023 LDB Astrophysics in Antarctica 5
LDB and Super-Pressure Balloon altitude
Why in Antarctica? How to preserve helium:
7th September 2023 LDB Astrophysics in Antarctica 6
About 161 day cumulative exposure
CREAM-I
12/16/04 - 1/27/05
Record breaking 42 days!
CREAM-IV
12/19/08-1/7/09
19 days
CREAM-II
12/16/05 - 1/13/06
28 days
CREAM-V
12/01/09 - 1/8/10
37 days 10 hours
CREAM-III
12/19/07-1/17/08
29 days
CREAM-VI
12/20/10 - 12/26/10
5 days 16 hours
7th September 2023 LDB Astrophysics in Antarctica 7
LDB base at Williams Field, Ross Ice Shelf
15 miles from McMurdo Antarctic Station
Two larger structures are the Payload Assembly buildings.
7th September 2023 LDB Astrophysics in Antarctica 8
Cosmic Ray Spectrum
Cosmic rays have been observed with
q
energies from 108 eV to over 10
Over this range, the flux of cosmic
q
rays ( the number of arriving particles
per unit area, per solid angle, per
unit time ) appears to follow a single
power law ~E-3.
The overall CR flux spectrum has
q
some noticeable structures. The most
prominent of these are small, abrupt
20
eV.
changes in the local spectral index
(the power exponent ~3) just above
1015 eV, and again just above 10
18
eV,
referred as the ‘Knee’ ( Supernova
Shock Acceleration limit? ) and the
‘Ankle’ - Greisen–Zatsepin–Kuzmin
limit (GZK)?
7th September 2023 LDB Astrophysics in Antarctica 9
HEAT LDB experiment
High Energy Antimatter Telescope
First observation of the primary positron component in the
Cosmic Rays “HEAT Bump”
HEAT instrument
7th September 2023 LDB Astrophysics in Antarctica 10
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