- 3871 - GAMMA RAY BURSTERS - and tiny satellites? - Tiny satellites could revolutionize the study of the most energetic explosion in the cosmos and help astronomers untangle the mysteries of colliding stellar remnants, Gamma Ray Bursters, that produce powerful gravitational waves.
----------- 3871 - GAMMA RAY BURSTERS - and tiny satellites?
- With tiny
budgets and a lot of resourcefulness nd energized in the early 2000s that had
given birth to “cubesats”, perhaps the space industry's most game-changing
innovation of recent decades. Cubesats
are one cubic foot in volume and can be lunched in bunches as cheap,
easy-to-build space gadgets.
-
- Gamma-ray
bursts are really bright and all you need is a relatively small detector to
spot them. Gamma-ray bursts are the
highest-energy explosions known to take place in the universe. Astronomers
believe that only the Big Bang produced more energy than these mysterious flashes
of super-energetic photons that come from distant galaxies.
-
-
Accidentally discovered in the 1960s by American satellites keeping an
eye on Russia's testing of nuclear weapons (which too produce the dangerous,
penetrating gamma radiation), gamma-ray bursts had long puzzled astronomers. While
some last a fraction of a second, others can brighten up the sky for several
minutes.
-
- It took
until the 1990s for astronomers to find that short gamma-ray bursts are likely
caused by collisions of neutron stars, super-dense remnants of giant stars that
prior to their death were over ten times more massive than our sun.
-
- The
long-lasting bursts, astronomers believe, occur when even larger stars explode
into supernovas at the end of their lives and then turn into black holes. Both
of these events emit jets of super energetic material that illuminate the
surrounding universe like the beam of a flashlight.
-
- Satellites
orbiting Earth only detect a gamma-ray burst when this flashlight is directed
toward our part of the cosmos, but detecting a gamma-ray burst is not a rare
event. Almost every day, one flashes briefly at our planet from somewhere in
the universe. Many more are believed to take place throughout the cosmos that
go undetected because the "flashlight" is not aimed at us.
-
- Because
gamma-ray bursts are so fleeting, astronomers don't always manage to locate
their source. In fact, only about 30% of detected gamma-ray bursts get tracked
to their origins.
-
- NASA's
nearly 15-year-old “Fermi” satellite are the current flagship gamma-ray burst
spotters. Optimized to detect super high energy gamma radiation, which is
billions of times more energetic than what human eyes can see, these two
spacecraft together detect the vast majority of gamma-ray bursts aimed at
Earth.
-
- Another
NASA spacecraft, 'Swift”, just a year and a half short of its 20th birthday, is
equipped to find the source of gamma-ray bursts. Swift, however, only sees
about one ninth of the sky. And since gamma-ray bursts are distributed evenly
all over the universe, Swift only detects a small fraction of them.
-
- Astronomers
want to know where gamma-ray bursts come from so that they can point other
types of telescope toward those sources, and study the aftermath of the
cataclysmic events that produced them.
-
- A
constellation of cubesats can cover the whole sky. That's a big advantage compared to the big
monolithic missions. The second advantage is that you can measure the difference
in time between when the different cubesats detect the gamma-ray burst and you
can triangulate the position of the gamma-ray burst on the sky.
-
- By 2018 a
new detector was developed that would fit on a “1U cubesat”, the smallest type
of cubesat measuring only 3.9 by 3.9 by 3.9 inches (10 by 10 by 10 centimeters)
in size.
-
- In March
2021, the world's first gamma-ray burst-detecting cubesat, called “GRBAlpha”,
shot off to space. GRBAlpha, the
smallest astrophysical satellite ever, has been orbiting Earth 340 miles above
the planet's surface. The innovative detector bolted to the tiny satellite's
surface has been exceeding the team's expectations from the start.
-
- The first
burst was detected in August 2021. Since then, GRBAlpha has detected 22
gamma-ray bursts. Three times larger
than GRBAlpha, the “VZLUSAT-2” has been orbiting Earth since January 2022,
having scored 12 gamma-ray bursts since then.
-
-
Gravitational waves were first predicted by Albert Einstein in 1916,
gravitational waves are ripples in spacetime that arise from the interplay of
gravitational forces of two or more supermassive objects, such as neutron stars
and black holes.
-
- Across the
universe, these objects frequently get pulled into each other's sphere of
gravitational influence and start orbiting each other. Gradually, they spiral
closer and closer to each other and eventually collide, the collision producing
a gravitational tsunami that can be detected from Earth by gravitational wave
detectors such as the American LIGO (The Laser Interferometer
Gravitational-Wave Observatory) and the European Gravitational Observatory
Virgo.
-
- Teams from
all over the world working on cubesat missions to detect gamma-ray bursts met
at a conference in Brno, the Czech Republic, in 2022.
-
- An Italian
project called “HERMES” to be a constellation of six gamma-ray burst-detecting
3U cubesats. The first of these spacecraft is expected to launch in 2024. Prior to that, the HERMES project team will
fly a hosted payload on a cubesat built by the University of Melbourne,
Australia, which is set for launch at the end of 2023.
-
- The HERMES
satellites are quite a bit more sophisticated than GRBAlpha, featuring a
detector sensitive to gamma-rays but also the slightly less energetic X-rays.
-
- The
satellites are also equipped with a set of high-tech sensors including GPS
receivers and accelerometers that will be able to report the spacecraft's
positions with an accuracy of a few meters.
-
- Since there
will be six of these satellites astronomers will be able, for the first time,
to use the minuscule time difference in the arrival of the gamma-ray burst at
the individual satellites, to calculate the location of the burst's
source. The time resolution is of about
300 nanoseconds.
-
- NASA is
also working on a gamma-ray burst-detecting cubesat. The “BurstCube” twice as
big as the HERMES satellites, is expected to launch by the end of 2023.
-
- GRBAlpha's
somewhat larger and more complex successor 'GRBBeta” has its ride to space
booked on the debut flight of Europe's new Ariane 6 heavy-lift rocket, which is
expected to take place by the end of this year,2022.
-
- Astreonomers
can all coordinate their efforts and build the constellation together. Most of
these cubesats are built by small teams that have limited funding, but by
working together, we can do it easier with the funding that we have.
-
February11, 2023 GAMMA RAY
BURSTERS - tiny satellites? 3871
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