#177 - Equinox to Black holes
This week we celebrate the life of Al Worden, talk about black hole resolution, the age of Ryugu, Astronaut advice, and some more news from the world of space.
“Where you stand on issues, how you live your life, and how much good you can do in the world are greater challenges than a lunar mission.”
Al Worden died on the 17th March.
The first person to do a deep space spacewalk, way back in 1971, about 200,000 miles from earth lasting about 40 minutes to retrieve data cassettes. Described as someone who lived in the moment by Dick Gordon (Al was his backup in Apollo 12)
One of only 24 people to have flown around the moon, a dwindling amount, less than half, are still alive. 4 moonwalkers left and now only 7 who stayed lonely on the command module.
Al made the lonely journey around the moon on his own like collins, Gordon, Swigert, Haise and Roosa before him. But unlike those, Al ventured outside of the craft into deep space., it remains one of only three that have ever taken place.
Guinness World Records "Most isolated human being" in the command module Endeavour as he orbited the Moon 74 times his distance from Scott and Irwin in the Falcon was 2,235 miles (3,597 km) away he was used to being alone as a fighter pilot and found the experience wonderful
He had a very rough time in the summer of 1972 when his world came crashing down as he was caught up in the scandal of secretly taking stamps to the moon. Literally everything he had worked towards and a lifetime of service ruined and he felt he had lost all respect A story he finally told eloquently, at 80 in his book falling to earth.
He clawed his way back and to many, he is a perfect example of an Apollo astronaut, with Apollo 15 regarded by many as one of the best missions in general.
March Equinox!! Or the Vernal Equinox, as Winter turns to Spring, or summer turns to autumn in the southern hemisphere. Today is the day that night is the same length as day, sort of , but atmospheric effects actually disguise that a little.
This year is a special one as it comes just over 18 hours earlier than last year, as it’s a leap year, which is kind of the point of leap years as it the leap year prevents the almost 6 hour drift each year taking the equinox beyond a day either side of March the 20th.
So for you astronomers, we are the Zero point of sidereal time and right ascension. Basically the earth appears to not tilt in relation to the direction of the suns rays and the axis of rotation.
So you could tell where the equinox was as it the sun would cross a celestial equator in a certain constellation, but the earth precesses in a 25,772-year cycle, so although this point is the first point of Aries it is moving and currently is in Pisces, where it has been since 68 BC, it was only in Aires from 1865 BC, and it will move into Aquarius in 2597
In Annapolis, Maryland in the United States, the boating community celebrate with the Burning of the Socks festival. Traditionally, they wear socks only during the winter. Which are then burned in the warmer weather, Officially, nobody then wears socks until the next equinox
China having its own turnarounds and entering a spring on many fronts.
China had a bit of a setback last week with the failure of the Long March 7A, this appears to be a second stage failure, which of all the things to go wrong is probably has the least knock-on effects for other launches, as there is little commonality with the 7A and other launch systems at this system point. And as if to add weight to that theory the Long March 5B, has been rolled out for testing. It currently has a boilerplate Chinese space station module on top for fit checks, but when it rolls out for the actual test flight in april it will have a uncrewed next-gen human-rated spacecraft on top.
Can the Americans keep up!!
Media accreditation is open for NASA’s SpaceX Demo-2 flight test,
which will send two astronauts, Doug Hurley and Bob Behnken, to the International Space Station as part of the agency’s Commercial Crew Program.
This mission will be the return of human spaceflight launch capabilities to the United States and the first launch of American astronauts aboard an American rocket and spacecraft since the final space shuttle mission on July 8, 2011.
NASA and SpaceX are currently targeting no earlier than mid-to-late May for launch.
The University of Luxembourg’s Interdisciplinary Centre for Security, Reliability and Trust (SnT) signed a partnership agreement with the UK space start-up LIFT ME OFF (LMO). The cooperation provides crucial research support for tackling future needs of autonomous in-orbit satellite repairs. In-orbit servicing operations like refueling and repairs are a key stepping-stone towards increasing humanity’s activities in space as it will pave the way for in-orbit construction.
In the next decade the amount of satellites to be launched is due to increase ten-fold. LIFT ME OFF wants to ensure that this growth remains sustainable and safe by providing the right innovation to make satellites:
Dynamic – With dedicated on-board propulsion
Flexible – Adaptable and reconfigurable for multiple mission scenarios
Servicable – By providing refuelling and other serivcing capabilities.
In order to do this it is developing the necessary technologies & services in the fields of Propulsion and Artificial Intelligence.
“We are only at the start of our collaboration with Dr. Aouada’s team and the fresh perspective from outside the space sector already delivers many insights,” said Michel Poucet, CEO of LIFT ME OFF. “SnT’s international team and its decade of terrestrial computer vision experience combined with LIFT ME OFF’s space experience makes SnT a perfect partner for helping us in our mission to make space safe and sustainable.”
Kids can watch astronauts reading stories from space while home from school due to COVID-19 pandemic
Astronauts on various missions in space are reading popular books to kids on Earth. Books include, "Ada Lace, Take Me to Your Leader" by the Emily Calandrelli (TheSpaceGal) and "Mousetronaut" - Mark “twin of Scott” Kelly
The Global Space Education Foundation foundation says the goal of Story Time from Space is to encourage reading among kids and to "provide families, educators & students with high-quality STEM and Literacy programming that utilizes the excitement of space exploration."
Astronauts also perform science demonstrations.
Story Time from Space isn't a new project. It was started by educator Patricia Tribe and astronaut Alvin Drew, according to the nonprofit. The free program is now gaining more attention with millions of students home from school in the U.S. due to the COVID-19 pandemic.
Chris Cassidy said Thursday that he won't have any guests at his April 9 launch from Kazakhstan. He expects to say goodbye in Russia to his wife on Friday, three weeks earlier than planned.
Former Navy seal deployed in Afghanistan straight after 911, flown on STS-127, Soyuz TMA-08M (Expedition 35/36), going up on Soyuz MS-16 (Expedition 62/63), only the second seal to fly to space.
Cassidy was Chief of the Astronaut Office at NASA in July 2015, succeeding Bob Behnken (the astronaut going up on SpaceX)
Cassidy when devastated for his colleagues when a rare late-in-the-game crew switch. He'll spend 6 1/2 months on the space station with two Russians assigned to the flight just a month ago after one of the original cosmonauts suffered an eye injury.
While training together to catch up, Cassidy, Anatoly Ivanishin and Ivan Vagner have been taking precautions to stay germ-free, frequently washing their hands and keeping a safe distance from others.
The space station crew will drop from six to three a week after his arrival. It will remain at three people until SpaceX launches two NASA astronauts, as early as May, or another crew arrives on a Russian Soyuz capsule in the fall.
With only three people on board, it promises to be extraordinarily busy.
Cassidy acknowledges his stress level is higher than usual right now from worrying about his loved ones.
“We're only human and we'll work through it and be fine.”
Nasa and ESA grind to a halt
“NASA will temporarily suspend production and testing of Space Launch System and Orion hardware. The NASA and contractors teams will complete an orderly shutdown that puts all hardware in a safe condition until work can resume. Once this is complete, personnel allowed onsite will be limited to those needed to protect life and critical infrastructure.
So do ESA ESA - Coronavirus and ESA's duty of care
ESA has taken steps to ensure the operation of its critical tasks while carefully reinforcing its duty of care and social responsibility.
ESA staff and contractors were advised to stay at home and take up teleworking, ESA decided to apply this condition to the majority of ESA personnel across all establishments. launch campaigns underway at the European Spaceport in Kourou, French Guiana has been suspended.
Universal interferometric signatures of a black hole’s photon ring
Michael D. Johnson, Center for Astrophysics | Harvard and Smithsonian et al
The Event Horizon Telescope image of the supermassive black hole in the galaxy M87 is dominated by a bright, unresolved ring. Using very long baseline interferometry (VLBI)
General relativity predicts that embedded within this image lies a thin “photon ring,” which is composed of an infinite sequence of self-similar subrings that are indexed by the number of photon orbits around the black hole.
The subrings approach the edge of the black hole “shadow,” becoming exponentially narrower but weaker with increasing orbit number, with seemingly negligible contributions from high-order subrings.
They show that these subrings produce strong and universal signatures on long interferometric baselines.
These signatures offer a promising approach for precisely determining the mass and spin of black holes and for testing general relativity using sparse interferometers, such as an extension of the EHT to space
Neglecting opacity, a telescope with perfect resolution directed at a black hole observes an infinite number of nested images of the universe. These images arise from photons that differ by the number n of half-orbits that they complete around the black hole on the way from their source to the detector. Each such image is thus an increasingly delayed and demagnified snapshot of the universe as seen from the black hole
In an astrophysical setting, this self-similar sequence of relativistic images is dominated by the luminous matter surrounding the black hole and produces in its image a feature known as the “photon ring” of the black hole
The leading (n = 1) subring appears as a sharp, bright feature in ray-traced images from many general relativistic magnetohydrodynamic (GRMHD) simulations
Successive subrings have exponentially sharper profiles and asymptotically approach the boundary of the black hole “shadow.”
For large n, these profiles mirror the leading subring in a manner that universally depends on the spacetime geometry, with the ratio of successive subring flux densities determined by Lyapunov exponents that characterize the instability of bound photon orbits.
Hence, measuring the size, shape, and thickness of the subrings would provide new and powerful probes of a black hole spacetime.
In this Research Article, they explore the photon ring’s theoretical underpinnings and show that, unexpectedly, precise measurements of the photon ring and even its subrings are feasible using interferometry
In summary, precise measurements of the size, shape, thickness, and angular profile of the nth photon subring of M87 and Sgr A* may be feasible for n = 1 using a high-frequency ground array or low Earth orbits, for n = 2 with a station on the Moon and for n = 3 with a station in L2.
An artificial impact on the asteroid 162173 Ryugu formed a crater in the gravity-dominated regime
M. Arakawa Kobe University et al
The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble pile structure.
impact experiment on Ryugu using Hayabusa2’s Small Carry-on Impactor (SCI).
The impact produced an artificial crater with a diameter >10 m, which has a semicircular shape, an elevated rim and a central pit.
Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 (DCAM3) for >8 min, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface.
The ejecta curtain was asymmetric, heterogeneous, and never fully detached from the surface.
The crater formed in the gravity-dominated regime i.e., crater growth was limited by gravity, not surface strength.
Based on collision frequency models for the asteroid Main Belt two estimates of the surface age of Ryugu have been obtained: about 160 million years for a surface composed of dry-soils with cohesion, or 9 million years for a cohesionless surface
The conclusion that the SCI crater was formed in the gravity-dominated regime on a cohesionless surface supports the younger age estimate.
It also suggests that the crater retention age of the top 1 m of Ryugu’s surface is 10,0000 years or younger, assuming crater production functions for near-Earth orbits
Lynk has achieved a historic “first”—sending the world’s first-ever text message from an orbiting satellite to a standard mobile phone on Earth.
the first (and only one so far) to test from space, the first to prove it works, and we will be the first to market.
This technical breakthrough is the next step on our mission to connect everyone, everywhere on their phone with broadband connectivity.
launched a real satellite “cell-tower-in-space” to test the ability to talk to standard mobile phones on the surface of the Earth. To date, we have launched four “cell-towers-in-space” satellites; that is one satellite cell-tower launched every 6 months.
And now, first to prove that this technology actually works. On Monday, February 24, 2020, we successfully transmitted the world's first text message from space to an unmodified mobile phone in the Falkland Islands.
This cell tower was actually physically attached to a Cygnus Cargo S.S Alan Bean spacecraft before it left the ISS by the all-female spacewalking duo of NASA astronauts Christina Koch and Jessica Meir, and is transmitting from this orbiting spacecraft until it is deorbited in April.