#131 - Magellan - Magellanic
It's a very sobering feeling to be up in space and realize that one's safety factor was determined by the lowest bidder on a government contract.
The 1st American in space on May 5, 1961. His suborbital flight took place just 3 weeks after the Soviet Union’s Yuri Gagarin orbited Earth once.
The first American to orbit Earth was John Glenn, aboard Friendship 7 on February 20, 1962.
OTD 4th of May 30 years ago;
STS-30 was the 29th NASA Space Shuttle, fourth mission for Space Shuttle Atlantis.
Commander David M. Walker
Pilot Ronald J. Grabe
Mission Specialist 1 Mark C. Lee,
Mission Specialist 2 Norman E. Thagard
Mission Specialist 3 Mary L. Cleave, First woman after challenger. New York - Biologist and doctor of Civil and Environmental Engineering from Utah State University.
STS-30 Deployed Nasa’s 5th Venus-bound probe- Magellan which mapped the surface of Venus by using synthetic aperture radar
Still the most detailed Venus map in existence, maybe the Russian Venera-D in 2026 earliest, may do better, by the end of the 1990s more detailed maps were available for parts of Venus than for our own Home Planet. whilst also able to measure the planetary gravitational field.
First interplanetary mission to be launched from the Space Shuttle, the trajectory specialists used a four-week period “Type IV Heliocentric Orbit”. 1.5 orbits of the Sun to arrive at Venus in August 1990. They could have used a quicker orbital route but that launch window was used by Galilleo
First spacecraft to test aerobraking as a method for circularizing its orbit.
First one to use the Inertial Upper Stage (IUS) a two-stage solid-fueled booster for Interplanetary mission, raising payloads from low Earth orbit to higher orbits or interplanetary trajectories not only from the Shuttle but the Titan family of rockets
In Interplanetary mode used the Oberth effect to acheive the escape velocity The second stage would ignite at low orbit (highest orbial speed). Used for Gallileo Probe (see podcast 110), Centaur could have launched Galileo directly on a two-year trip to Jupiter, the IUS required a six-year voyage with multiple gravity assists
Used for Ulysses Sun probe, as pictured above, a Joint Nasa/ESA with a bit of help from Canada too.
Used for Chandra X-ray Observatory
Megellan had to used really big atitude control thrusters on boom as large as the shuttle cargo bay would allow to counteract any spin caused by the solid rocket engine.
To save costs, most of the Magellan probe was made up of spare parts from various missions, including the Voyager program, Galileo, Ulysses, and Mariner 9.
In September 1994, the orbit of Magellan was lowered to begin the "Windmill experiment". During the experiment, the spacecraft was oriented with the solar arrays broadly, perpendicular to the orbital path, where they could act as paddles as they impacted molecules of the upper-Venusian atmosphere. Countering this force, the thrusters fired to keep the spacecraft from spinning. This provided data on the basic oxygen gas-surface interaction. This was useful for understanding the impact of upper-atmospheric forces which aided in designing future Earth-orbiting satellites, and methods for aerobraking during future planetary spacecraft missions
The experiment lasted for two weeks and was followed by subsequent orbital trim maneuvers, further lowering the altitude of the spacecraft for the final termination phase
October 11, 1994, moving at a velocity of 7 kilometers/second, the final orbital trim maneuver was performed, placing the spacecraft 139.7 kilometers above the surface,
Burnt up in atmosphere but bits may have made it to the surface.
SPACE WORD OF THE WEEK (SWOTW)
Steve: is a surprisingly common, or at least not rare, atmospheric optical phenomenon, a purple and green light ribbon in the sky, formally discovered in late 2016 by members of a Facebook group called Alberta Aurora Chasers in canada
Photo by Elfie Hall.
photographer Chris Ratzlaff, suggested the name "Steve" from Over the Hedge
A scientist listening to Eric Donovan's presentation at the December, 2016, meeting of the American Geophysical Union suggested "Strong Thermal Emission Velocity Enhancement" as a backronym of STEVE, adopted by NASA Goddard Space Flight Center
According to analysis of satellite data from the European Space Agency's Swarm mission,
Steve is a 25 km (16 mi) wide ribbon of hot plasma at an altitude of 280 miles with a temperature of 3,000 °C and flowing at a speed of 13300 mph compared to 22mph outside the ribbon.
In August 2018 a scientific paper by B. Gallardo‐Lacourt J. Liang Y. Nishimura E. Donovan verify that this STEVE event is clearly distinct from the aurora since it is characterized by the absence of particle precipitation. Interestingly, its skyglow could be generated by a new and fundamentally different mechanism in the ionosphere.
Steve has only been spotted in the presence of an aurora. Steve was not observed from October 2016 to February 2017, or from October 2017 to February 2018, leading NASA to believe that Steve may only appear in certain seasons
Steve has been observed in the United Kingdom, as well as Canada, Alaska, northern U.S. states and New Zealand
We’re now seeing possible weekly gravitational wave detections
25 April, possible dtection looks like two neutron stars that co-orbited and then collided 500 million light-years away.
26thApril - potential first-ever observation of a black hole drawing in a neutron star and swallowing it whole. 1.2 billion light years of intergalactic space before it arrived at Earth.
How the improvement
high-efficiency mirrors that reflect light back with low mechanical or thermal energy transfer from the light ray to the mirror
Squeezed light. Because they are at teh quatum level they are in the realms of heisenberg uncertainty, as you icrease the accuracy of one measurement you loose the accuracy of the other, for example speed and position ...hence the joke. ...An electron is speeding down the highway when a police officer pulls him over.The officer walks up to the car and asks, "do you know how fast you were going."The electron replies, "Yeah, but now I'm lost.".
So they make the amplitude of the light noisy so they have a better reading of the frequency or phase.
Multimessenger potential of neutron star and black hole interaction huge deal.
SPACE FACT OF THE WEEK.
Honing in on the biggest problem in cosmology
paper Adam Riess et al., “Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM,” accepted at the Astrophysical Journal
Hubble's measurements of today's expansion rate do not match the rate that was expected based on how the Universe appeared shortly after the Big Bang over 13 billion years ago, hear podcast 122,
Using new data from the NASA/ESA Hubble Space Telescope, Nobel prize winning Adam Riess is working with a team called SHOES, for Supernovae, H0, for the Equation of State have significantly lowered the possibility that this discrepancy is a fluke.
Measuring 70 Cepheid in the Large Magellanic Cloud, 162 000 light-years away.
This latest research has reduced the uncertainty in their Hubble constant value to an unprecedented 1.9%
Discrepancy between measurements of today's expansion rate of the Universe and the expected value based on the early Universe's expansion is a fluke is just 1 in 100 000, a significant improvement from a previous estimate last year of 1 in 3000 - “This disparity could not plausibly occur by chance.”
The new estimate of the Hubble constant is 74.03 kilometres per second per megaparsec. The number indicates that the Universe is expanding at a rate about 9 percent faster than that implied by Planck's observations of the early Universe, which give a value for the Hubble constant of 67.4 kilometres per second per megaparsec.
This means that for every 3.3 million light-years further away a galaxy is from us, it appears to be moving about 74 kilometres per second faster, as a result of the expansion of the Universe.
“The Hubble tension between the early and late Universe may be the most exciting development in cosmology in decades, This mismatch has been growing and has now reached a point that is really impossible to dismiss as a fluke.”