8.28.25

Episode Transcript

Speaker 1 (00:01):
Welcome to Radio Wized Diary of Science and Nature, your readers.
Kelly Taylor. I'll have some articles on the topics of
science and nature, but first a reminder that RADIOI is
a reading service intended for people who are blind or
have other disabilities that make it difficult to reprinted material.
From Scientific American we have this article dated August twenty second.

(00:25):
Can SpaceX solve its exploding starships problem? Kaboom is not
the sound you want a rocket ship to make as
a rule, yet that's the problem facing the private aerospace
company's SpaceX and its leader Elon Musk. Instead of going
to space, their newest rocket ship keeps going kaboom. The

(00:47):
last three flights of Starship, a two stage, four hundred
foot tall vehema, ended in fiery disaster what Musk has
sometimes jokingly called a quote rapid unplanned disassembly. In January
and again in March, the launch vehicle's super heavy booster

(01:07):
made it back to a massive pincer equipped gantry, but
Starship's upper stage didn't. In May, the booster exploded just
before splashdown, and Starship broke up spectacularly in the atmosphere,
raining debris that commercial aircraft had to dodge as a bonus.

(01:30):
In June, the upper stage detonated on the launch pad
while Starship was getting fuel for a test firing of
its engines. The tally for twenty twenty five thus far
is explosions four SpaceX zero. Today, Starships super Heavy booster
and upper stage or on the launch pad yet again.

(01:50):
The tenth test flight is scheduled for liftoff on Sunday
around seven thirty pm from SpaceX's Starbase launch site in
South Texas. If all goes to plan, the booster will
use its thirty three rocket engines to push the whole
chipang to the edge of space, then drop off somersault,
execute a boost back burn, and descend to a soft

(02:13):
splashdown into Gulf of Mexico. Meanwhile, Starship's upper states should
be firing its rockets to reach orbit, where it will
deploy some cargo before flying itself back down through the
atmosphere to its own splash down about an hour and
fifteen minutes after launch. Excitement guaranteed in quotes a SpaceX

(02:33):
announcement promises, but there's excitement, and there's excitement. Look, going
to space is hard. It's even harder to do in
the way SpaceX is attempting. Quote, it's one of the
biggest rockets ever. It's for sure the biggest rocket that
has attempted reuse, says Jonathan McDowell, an astrophysicist at the
Center for Astrophysics at the Harvard and Smithsonian who tracks

(02:58):
space launches in his spare time. Quote, Developing a vehicle
this big and launching it repeatedly ain't easy. In quote,
Starship isn't just an oligarch's polly. It's a launch system
meant to revolutionize space light by flying cargo and cruise
to orbit at a cost that's almost too cheap to meter.

(03:20):
It's supposed to stake to take NASA astronauts back to
the Moon and human setlers to Mars, and it represents
the kind of gleaming hardware forward future that Silicon Valley's
techno optimists are always promising. Starship is the lynchpin of
a lot of plans and schemes over the past few months.

(03:41):
SpaceX has acknowledged which pieces of the ship broke with
each flight, but hasn't gone into any great detail about why.
The company didn't return requests for comment from Scientific American,
but SpaceX is very online rocket spotting fans, and the
half dozen aerospace engineers I talked to have been willing

(04:01):
to speculate what the problems might be. Mostly they believe
the company has some brilliant people who stand every chance
of solving them. But they also wonder what will happen
if SpaceX can't figure out what's wrong, or even worse,
if some fundamental engineering issue means the idea of a reusable,
reliable workhorse Spaceship stays confined to science fiction those SpaceX

(04:27):
characterizes this differently. Starship had essentially the same types of
mishap in all three of the most recent flights, leaks, fires,
and explosions in the fuel system. On flight seven, there
is a flash and then a fire in the unpressurized
attic that's in quotes below the bottom of Starship's liquid

(04:51):
oxygen tech. On flight eight, that happened near one of
the rocket engines. On flight nine, fuel leaked into the
rose cone. That fuel and the plumbing to move it
around might be the problem. It's a mix of liquid
methane and liquid oxygen of volatile cryogenic cocktail that's still

(05:11):
by rocket science standards experimental to stay liquid methane has
to be below negative two hundred and fifty nine degrees
fahrenheit negative one hundred and sixty two degrees celsius, and
oxygen has to be even cover below negative to ninety
seven degrees faharadyt. That means a lot of mechanical effort
to keep it cold, to move it around on the

(05:33):
ground and on the vehicle, and to accommodate it as
it shifts from liquid to gas and gets lit on fire.
Going back and forth from super cold to hot is
called thermal cycling. Without careful design and maintenance, almost anything
under those conditions will break in a Muskian science fiction future,

(05:54):
that's all worth it. Cryogenic fuel is a pain and asteroid,
but it has more umph propound as gojus what engineers
call specific impulse, and fuels like methane offer the tantalizing
possibility that they could be harvested in c TU on
another world, that they could be synthesized from carbon dioxide

(06:17):
and frozen water in Martian regulate, or say, slurped up
from the roiling methane seas of Titan. And that makes
living off the land in space seem feasible, even though
nobody really knows how to do it yet. Quote. Methane
is a new rocket propellant for space launch, so we're
still learning how to do the methane plumbing. The fact

(06:40):
that they've had leaks, the fact that they've had overheating,
doesn't really surprise me. McDowell says. It's a different sized molecule,
bigger than liquid hydrogen but smaller than kerosene, so it
leaks differently in different circumstances. It's chemistry is different, but
the croogenic chemistry here may be less elevant than cold mathematics.

(07:02):
Anything going to space has to carry its own fuel,
but that fuel itself has mass. Quote. That's the tyranny
of the rocket equation, says Hassan sod Ifty, aerospace engineer
at Texas A and M University, referring to the calculation
that vexes every would be space jockey. Quote. You need

(07:23):
to carry more to deliver what you want, but more
fuel means more fuel for the fuel end quote. That's
why rockets often have stages or external boosters. When they
run out of fuel, you'd drop those components so that
the rockets will have less mass to lift. Musk's ambitious
goal is for Starship to carry between one hundred and

(07:43):
ten and one hundred and sixty five tons of payload
to orbit, five times what a NASA Space shuttle can
handle by way of comparison. But to make that work,
the vehicle itself, the dry mass, without propellant, rocket engines,
and all the plumbing has to be extraordinarily light. SpaceX

(08:04):
is aiming for a structural ratio the dry mass divided
by the sum of the dry mass and the propellant
of zero point zero five for both stages. Quote. Most
typical rocket designs, that ratio is around point one, says
John Deck, an aerospace engineer at Georgia Institute of Technology.

(08:24):
In other words, Starship is on a pretty extreme weight
loss regime. Some observers and engineers speculate the diet might
be the problem. After the failure on flight seven, SpaceX's
official blog reported that the cause of the leaks and
fire was a quote harmonic response several times stronger than
had been seen during testing, which led to increased stress

(08:47):
on hardware in the propulsion system end quote. That is,
some Starship's hardware shook itself apart. Deck was previously at
NASA and his specialty there was entry descent bringing space
probes down to the surface of Mars. It's one of
aerospace engineering's hardest challenges. For one thing, the atmosphere gets

(09:10):
thicker as you get closer to a planet's surface, so
the force of drag on a descending vehicle changes depending
on both the density of the air and the speed
of the vehicle. Drag becomes, in the language of engineering,
a dynamic load. Quote. If dynamic loads are changing fast enough,
they can cause the vehicle to start to vibrate. Debt says,

(09:32):
vibrate all that complicated cryogenic plumbing too much, and very
bad things happen. After flight seven, SpaceX hardened fuel lines
to the engines and added vents and the nitrogen gas
purge system to the attic where the leaks happened. To
deal happened to deal with the possibility of fires. After
flight eight, SpaceX insisted that the problems that Starship face

(09:57):
were completely different, but bloggers. When Redditors passed around a
purported leak from an insider saying that the root issue
hadn't changed. It was quote harmonic oscillations in quote vibrations again,
this time busting methane lines running through the liquid oxygen tank. Again.

(10:18):
When the tank was full of liquid oxygen, it dampened
the vibrations, but as the tank empty, the shaking got worse.
Starships two stages have to structurally support nearly eleven eleven
million pounds of fuel. The upper stage is meant to
carry as much as three hundred and thirty thousand pounds
of payload, so the vessel itself has to be as

(10:40):
light as possible yet still withstand the buffeting forces of
launch and re entry. So far it has not. Quote
they've designed their structure light enough to perform when the
rocketing nights and once to fly. But maybe, and this
is speculation, when they're loading the fuel that's causing cracking.
Neck says. Quote. When a structure is cool, it shrinks.

(11:03):
If it's rigid and can't move, that's going to cause
a stress and it's going to break in quote. A
couple of other pieces of evidence fit this theory. One
reason the booster may have survived flights that the upper
stage did not is that the booster doesn't go all
the way to space, and it comes back to the
ground at only about forty six hundred miles per hour.

(11:23):
Starship's upper stage goes all the way to orbit and
reaches seventeen thousand, five hundred miles per hour. That's a
lot of kinetic energy to get rid of on re entry,
usually as heat. Quote this is the physical constraint. If
he says, we can't get away from it. We have
to manage this entry, this energy. I'm sorry, we have

(11:46):
to manage this energy being generated through heating in quote.
An early version of Starship tried to bleed off that
kinetic energy with a kind of aerodynamic belly flop that
ended in a catastrophic law of control. Now the vehicle
uses its control surfaces and rockets to slow its descent

(12:06):
and relies on heat resistant tiles, which of course add weight.
One persistent critic of SpaceX, Will Locket, has argued that
Starship simply must use more propellant than its builders expected
for its return flights, adding even more weight. Quote this
puts incredible pressure on SpaceX to save weight anywhere they

(12:28):
possibly can, Lockett wrote in his newsletter in March. Quote
SpaceX is having to make the rockets too light, resulting
in them being fragile, meaning that just the vibrations from
operation with a fraction of its expected payload would be
enough to destroy the rocket in kaboom. Maybe this build, test, destroy,

(12:53):
rebuild cycle is what you'd expect from a cutting edge
company like SpaceX, which owes much of its astonishing access
to iterating like a software startup. The version of Super
Heavy that's set to launch on Sunday has some major
design changes, increasing the size and strength of the winglets
called grid fins, but reducing their number from four to three,

(13:15):
and aiming for a more controlled, higher angle of attack descent.
Starship's upper stage will also test several new kinds of
tiles to protect against the ferocious heat of reentry. This
is what coders call agile. In practice, though this Silicon
Valley style approach forces SpaceX to play a very expensive

(13:36):
game of whack a mole. Quote the way I read
what Elon's trying to do while is it complicated. And
when you deal with a very complicated device, there's multiple
modes of failure, says Joseph Powers, an aerospace engineer at
the University of Notre Dame, an editor in chief of
the Journal of Propulsion and Power. Quote, with a rocket

(13:58):
that almost always results in detonation, each failure is supposed
to be an opportunity to learn to avoid disaster the
next time. Quote. They're facing challenges, but I don't see
any showstoppers. McNeal says, I don't want to minimize the
problems they're having. It's embarrassing for SpaceX, and they do
have to fix these things, but they are making progress in.

Speaker 2 (14:20):
Quote and then we'll turn to Earth dot com. And
this article is from August twenty sixth Driving change. Electric
vehicles slash emissions across America. Choosing a more.

Speaker 1 (14:37):
Electrified vehicle lowers your greenhouse gas footprint, no matter which
country you call home, and no matter which county you
call home. A new analysis shows battery electric vehicles to
deliver the lowest lifetime emissions in every part of the
contiguous United States, with hybrids and plug in hybrids also

(14:59):
beating their gasoline counterparts. Researchers at the University of Michigan
mapped cradle to grave emissions for thirty five combinations of
electric vehicle class and powertrain, then compared results county by county.
The team also released a free online calculator so drivers

(15:19):
can see estimates tailored to what they drive, how they drive,
and where they drive. Study senior author Greg Caitlin is
a professor at the University of Michigan School for Environments Sustainability. Quote,
Vehicle electrification is a key strategy for climate action. Transportation
accounts for twenty eight percent of greenhouse gas emissions, and

(15:42):
we need to reduce those to limit future climate impacts
such as flooding, wildfires, and drought events, which are increasing
in intensity and frequency, said Kaitlin. Our purpose here was
to evaluate the cradle to greenhouse gas reduction from the
electric vacation of vehicles compare with the baseline of gasoline

(16:04):
powered vehicles. The researchers callied emissions for manufacturing, use, and
end of life, then layered in real world variables. They
modeled four power trains, conventional internal combustion or ICEV, hybrid HEV,

(16:25):
plug in hybrid pH EV, and battery electric b EV. Afterwards,
the team ran three body classes pickup, SUV and sedan,
using generic twenty twenty five vehicles that reflect what new
buyers will see on lots. They captured driving style city

(16:45):
versus highway mix, and for phivs how often owners actually
run on battery versus gasoline. Geography mattered in two ways.
Cold snaps, cold snaps redew efficiency for all vehicles and
trim electric range. In addition, the carbon intensity of electricity

(17:07):
varies widely across counties, so the same ev charged for
a cleaner grid emits less per mile than it would
in a coal heavy region. Even after accounting for those differences,
battery electric vehicles still came out ahead everywhere. The major
finding is simple. Deeds produce lower lifetime greenhouse gas emissions

(17:29):
than any other powertrain in every county of the contiguous
United States. On average, gasoline pickups were the biggest emeters,
at four hundred and eighty six grams of carbon dioxide
equivalent per mile. Moving to a hybrid pickup cut that
by about twenty three percent. A battery electric pickup cut

(17:49):
it by roughly seventy five percent. Payload didn't erase the advantage.
A battery electric vehicle pickup carrying twenty five hundred pounds
still emitted less than thirty percent of a gasoline pickup
with an empty van. On the other end of the spectrum,
compact electric sedans were the cleanest choice, at about eighty

(18:10):
one grams of CO equivalent per mile, less than one
fifth the per mile emissions of a gas pickup range
matters for manufacturing emissions. The lowest emitting configuration in the
study was a compact Sedan VIEV with a two hundred
mile range. Bigger batteries ad manufacturing impact, so stretching range

(18:34):
nudges lifetime totals up, even as evs retained their use
phase advantage. While federal incentives are in flux, automakers are
still steering toward electrification. Ford recently touted a new more
affordable EV platform as a model t moment for the company.

(18:55):
Kalen noted the policy industry split that said the global
tree and is clear quote the government is backing off
incentives like the electric Vehicle tax credit, but the original
equipment manufacturers are heavily invested and focused on the technology
and affordability of evs. EDS are becoming the dominant powertrain

(19:16):
in other parts of the world, and manufacturers recognize that
is the future for the US. Two nearby drivers can
have different footprints in the same model. Colder counties impose
higher energy demand for heating and reduce CV range. Grid
mix shifts by county and over time, altering the emissions

(19:38):
tied to every kilowatt hour. Behavior matters too aggressive driving
burns more fuel. PHEVs shine only when they are plugged
in often and driven mostly on electricity. The calculator makes
those nuances into individualized estimates. Electrification delivers the biggest drop,

(19:59):
choosing as smaller vehicle compounds the game or many commuters.
Compact EEV does the most to cut emissions per mile. Trades,
people who need a truck will still make a large
dint by going hybrid or electric. Quote. The thing is
really matching your vehicle with your needs. Kale And said, Obviously,

(20:20):
if you're in the trades, you may need a pickup truck,
but you can get a battery electric pickup truck. If
you're just commuting to work by yourself, I'd recommend to
SEDANVIEV instead. In quote. Now we'll go to BBC Wildlife
and the article headline is ten deadliest cats in the world,

(20:41):
Which the lines are the best killers and which attack humans?
From August twenty sixth from Tiny Mouse Slayers Legendary man Eaters.
Cats are among nature's most efficient predators, says summer Ryelander,
a journalist and photographer for UC Wildlife. Here we rank

(21:06):
ten wild elines through a combination of their hunting success
rate and likelihood of causing us harm, so deadliest cats
in the world. Number one leopard. Leopards are skilled hunters
for a thirty eight percent success rate. They're beautiful. Rosetted
coats are unmistakable across Africa, Asia and some parts of

(21:30):
the Middle East, but these big cats are best admired
from the distance. Solitary and territorial leopards are on the
Big five list of African wildlife, along with lions, elephants, rhino,
and cape buffalo, not for their size, but for the
difficulty and danger they presented to the big game hunters
of yesteryear. Leopard attacks on humans do happen in Africa,

(21:54):
but they're far more commonplace in India, where habitat loss
leads to an increase in human wildlife conflict. While exact
numbers are difficult to pinpoint, the International Union for Conservation
of Nature estimates three hundred and fifty to four hundred
and fifty leopard attacks per year, with ten percent to
fifteen percent ending in human fatality. Number two the lion.

(22:20):
The iconic lion needs little introduction. African lions are social cats,
often living in prides among grassy savannahs, woodlands and sometimes deserts.
They're not the most successful hunters, with a twenty five
to thirty percent kill rate, but they're also not afraid
to steal a kill from fellow carnivores like hyenas and
wild dogs. Estimates fall between two hundred to two hundred

(22:43):
and fifty lion attacks on humans annually, but like leopards,
lions usually only attack humans with cause, such as when
feeling threatened or desperate due to prey scarcity. There are
two famous exceptions, though. A pair of male lions that
came to be known as the Tsavo man eaters killed
dozens of railway workers in Kenya's Savo region between March

(23:08):
and December of eighteen ninety eight. Actual figures are unknown,
with some estimates as high as one hundred and thirty
five deaths and more recent studies suggesting a figures closer
to thirty five, but it is clear the two lions
were targeting humans as prey number three. The tiger tigers
are the largest of the big cats, and though they

(23:29):
have a relatively low hunting success rate at five and
ten percent, their sheer, size and power makes them formidable credators.
Tigers can take down buffalo, deer, and wild boar, often
relying on an ambush technique rather than chasing their prey.
These remarkable cats can be found in several Asian countries,
though more than seventy percent live in India. Humans are

(23:54):
well advised to steer clear of close encounters with tigers.
They're unlikely to attack without provocation, but estimates indicate approximately
fifty six human deaths per year occur at the claws
and jaws of a tiger. Number four is the jaguar,
the third largest cat in the world. Jaguars are perhaps

(24:14):
best known for their semi aquatic habitats. Jaguars live in
Central and South America, often in rainforests and lush wetlands
like Brazil's biodiverse Panthanal. Here, they use their exceptionally strong
jaws to prey, with the twenty percent to thirty percent
success rate upon caymans, a small species of alligator and

(24:39):
capibaras as well as fish, turtles, papers, and deer. Number
five is the cheetah. As the fastest land animal in
the world, the sleek cheetah uses its phenomenal speed to
make a quick work of its prey. Cheetahs have an
impressive fifty eight percent kill rate pursuing antelope, warthogs, hares,

(25:02):
and birds, among other species. These lanky cats can exceed
ninety centimeters in height, with long tails that help them
balance at high speeds. Most cheetahs are found in sub
Saharan Africa, with a small population in Iran. While cheetahs
are certainly capable of harming or killing a human, cheetah

(25:22):
attacks are rare enough that there are no documented cases
of a wild cheeta killing a person. Incidents that do
occur are nearly always with a captive animal. Number six
the mountain lion, also known as pumas and cougars. It
lives primarily in forested regions of North and South America.

(25:43):
These stealthy and deadly cats hunt deer, elk, and small
mammals such as squirrels and rabbits, utilizing their speed and
agility to take prey by surprise. Mountain lions have a
solid kill rate of about twenty percent, and their willingness
to take livestock occasionally fuels conflict with humans. Fountain lion

(26:04):
attacks on humans are not common, but they can happen,
and attack that occurred in California in March of twenty
twenty four made headlines as the state's first fatal one
in two decades. Number seven the snow leopard. Among the
most elusive of wildcats is the snow leopard. They live
at high altitudes in Central and South Asia, protected from

(26:26):
the cold by their dense, well camouflaged fur. Despite harsh
conditions and an estimated kill rate of ten or fifteen percent,
snow leopards are comparatively excellent hunters. Their strength allows them
to leap fifteen meters high and take down prey three
times their size. Due to their remote habitat, snow leopards

(26:47):
are not considered outwardly deadly to humans. Number eight The servile.
Servals are fast, capable of speeds around sixty five kilometers
per hour and their excellent hunters with two percent success rate,
preying on rodents, frogs, and birds, and even snatching the
latter out of the air with an impressive two meter

(27:08):
vertical leaf. Servals are not considered dangerous to humans, though
provoking one may well prompt an unpleasant attack. Number nine
black footed cat. Black footed cats live in Southern Africa,
primarily Botswana, South Africa, Namibia, Namidia, and hunt rodent small birds, insects,
the occasional hair. Much of their success comes from skill,

(27:33):
some of it can be attributed to frequency. Black footed
cats spend about seventy percent of the night hunting and
perhaps unsurprisingly, these little cats pose no threat to humans
and finally number ten, the rusty spotted cat. The rusty
spotted cat is thought to have a similar hunting success
rate to the black footed cat, using its speed an

(27:54):
incredible eyesight to overtake prey. It is maybe deadly, but
it is not a danger to humans. Well that's offer
today's diary of science and nature. Your reader was Kelly Taylor.
Now stay tuned for further programming on the RADIOI