Joan Strothers Curran and Radar Countermeasures

Curran was a Welsh scientist who developed a system of thwarting radar for the Allied forces in WWII. What we know of her work is entirely pieced together from accounts by her male colleagues, who, fortunately, recognized the importance of her contributions.

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Episode Transcript

Speaker 1 (00:01):
Welcome to Stuff You Missed in History Class, a production
of I Heart Radios How Stuff Works. Hello, and welcome
to the podcast. I'm Holly Fry and I'm Tracy V. Wilson.
And today we're talking about a woman who is not
a household name, but in my opinion she probably should be.

(00:22):
There are some other people who think she probably should
be as well. Uh. She was a Welsh scientist who
developed a system of thwarting radar that was invaluable to
the Allied forces during World War Two, and what we
know of her work is unfortunately entirely pieced together from
accounts by her male colleagues, who fortunately recognized the importance
of her contributions. So today we are talking about Joan

(00:44):
Struthers current. Joan Struthers was born February nineteen sixteen and Swansea, Wales.
Joan attended the Swansea Girls High School. She went a
scholarship to Newnham College at the University of Cambridge and
she enrolled there in nineteen thirty four. She studied physics.
Of note here is the fact that Joan, despite doing

(01:04):
all of the required coursework at Cambridge, did not get
a physics degree That was because it was policy not
to issue them two women. So when she finished her
undergraduate coursework in ninety eight, but again not a degree,
she started her doctor at work and that was actually
funded by a government grant and that work was carried
out at Cambridge's Cavendish Laboratory and it was there that

(01:27):
she met a man named Samuel Curran who she was
assigned as a lab partner. Yeah, this whole deal where
you could do the whole of the coursework and not
be awarded a degree because you're a woman like that
was not unique to Cambridge. We've talked about that happening
in other schools too. Yeah. Absolutely, that was pretty much
der rigor across academia and the nineteen thirties. Yea. So
in nineteen forty, Struther and Karen were moved from their

(01:50):
physics work at the Cavendish Lab to Exeter and there
they were both assigned to research that was to help
the war effort. They turned their problem solving skill to
the development of proximity fuses. These are explosive device sugars
that since when their targets are within a specified range,
so close enough to cause damage and then detonate the
proximity fuses that Joan Struthers and Samuel Kerran developed targeted

(02:13):
rockets and aircraft, and they developed a very closely should
JIP over the course of the years being lab partners,
and in November nineteen forty Joan and Samuel married and
not long after the currents had said their vows, they
were reassigned. This time they were sent to the Telecommunications
Research Establishment. This was again part of the war effort,
and sam worked on centimeter radar and Joan worked in countermeasures.

(02:37):
The goal for Jon's work was to figure out a
way to fool enemy radar, and the team on this
project was led by Robert Cockburn under the leadership of
Reginald Victor Jones, who was a British physicist who had
become an expert in military intelligence. Just as a quick
refresher on radar, that stands for radio detection and ranging. Basically,

(02:57):
radar works by sending out a radio signal and wonder action.
It looks for a bounce or an echo of that signal,
which would indicate that their objects in the path of
the signal. Then, using the information gathered that way, including
the time it takes for the echo to return, to
the point of transmission. Radar can indicate the size, shape,
and distance of objects, so the team commissioned by Jones

(03:19):
had to somehow thwart that process, and so one of
the experiments that Joan Curran began was using thin metal
reflectors to disrupt the echo of radar. Large groups of
small metal strips could even mimic a large object like
an aircraft, when in reality there was nothing substantial there.
Even larger groups of strips could create large amorphous blobs

(03:42):
that were big enough to hide an aircraft inside. Even
if an enemy knew that a plane was somewhere inside
such a blob, Figuring out where would be a complete
guess if that blob was big enough. And Jones is
credited with coming up with this idea and then passing
it off to the research group to figure out the
particular killers and do testing, and Joan Curran really did

(04:03):
a lot of that research. Jones later described the concept
in this way years later in his book, which is
titled The Most Secret War Quote. The phenomenon on which
they depended was that of resonance. If a reflector is
made of a simple wire or strip of metal of
length equal to half the wavelength used by the radar station.
It resonates to the incoming radio waves and reradiates them

(04:25):
to such effect that it is roughly equivalent to a
whole sheet of metal whose dimensions are square and which
has sides equal in length to half a wavelength. Thus,
a few hundreds such strips or wires would reflect as
much energy as a whole Lancaster bomber. If you recall
our episode on the twenty third Headquarters Special Troops that

(04:46):
are known as the Ghost Army, you know that creative
deception was a valuable tool in the Allied Forces World
War two plans. But at the point when Current and
the team led by Jones were working on their radar
disruptor technology, the US was and even involved in World
War Two. Yet Current and her colleagues were leading the
effort in trickery as a military strategy, figuring out ways

(05:07):
that blobs of reflective material could hint at a faux
massive attack force or simply obscure one or two aircraft.
And so the practical idea of how this would work
is that a lead aircraft would drop bundles of strips
to create this radar confusion, and then dropping additional bundles
at regular intervals would create complete mayhem for enemy forces

(05:30):
that were trying to get a read on this situation.
This technology was given the code name Window by British intelligence,
although the U S would eventually just kind of use
the more casual term of radar chaff. Even after the
December seven one bombing of Pearl Harbor, which brought the
United States into the war, Curran's work was still in
the experimental stage. She was testing the best possible materials,

(05:52):
the best possible shapes and sizes for these strips. Those
decisions weren't made until two and the technology wasn't put
into use until ninety three. She performed test first at
Swantage on the aisle of Pierbeck and then later at Malvern, Worcestershire.
Everything from pieces of metal as big as slips of paper,
which were considered as a possible propaganda delivery system as

(06:15):
well as being part of this radar disruption. Two very
tiny wires were tested before the research led to the
decision that aluminum cut into one point five by time
strips was the best That is a little bit more
than half an inch by a little less than ten inches.
According to RV. Jones, the intention had actually been to
first use the system Joan Current had tested as early

(06:38):
as May of nineteen forty two. He wrote, with the
chiefs of Staff's approval, the window packets where I believe
actually loaded into bombers for a raid in May two
and then we're offloaded again because there was a last
minute prohibition of their use. And the reason for that
last minute change, according to Jones, was that Fighter Commands
Airborne radar Officer Derek Jackson had only heard about the

(07:01):
existence of Window right before the mission, and Jackson was
understandably concerned that those reflectors might also cause confusion to
the radar texts in the British forces, and so he
was not comfortable using a brand new technology that he
had only just heard of during an active raid. So
Window was pulled for additional testing. We'll talk more about

(07:21):
how this technique for confusing Germany's radar was eventually put
to use, but first we will pause or a sponsor
break RV. Jones was against withholding the use of Window,
although he also wanted to make sure that when they
did deploy it, it was at a time when it

(07:41):
would be the most effective and impactful In October ninety two,
British intelligence received information that indicated that the Germans knew
about this concept, having fired on a dust cloud of
aluminum particles that was thrown out of an Allied craft
in the Rhineland. Jones made the case to command that
they should absolutely used window immediately before German forces might

(08:04):
have a chance to figure out a way around it,
perhaps even introduced their own version of it, but his
efforts were met with dismissal. This discussion did, however, lead
to a more detailed analysis of window and how it
would impact both the Germans and the British. This led
to more specifications around the exact amounts of window material
that should be used for various results, and also the

(08:25):
calculations of its value in terms of potential casualty reduction.
As people were calculating these things, how much to use
and what it was what its real value was in
terms of war effort, they came up with some different numbers.
Dereck Jackson, who was that man who had halted the
initial use of window, worked on this analysis as well,
and he came up with the weight of eighty four

(08:47):
tons of window as the amount needed to make Germany's
radar useless. Jackson also believed to reciprocate German forces could
render Allied radar ineffective with just one ton of a
similar material. R V. Jones made his own calculation, remember
he had really um birthed this whole idea, and he
landed at twelve tons as the amount needed to wipe

(09:09):
out the effectiveness of Germany's radar, and then a whole
other colleague came up with the number of forty eight tons.
So they were all over the map and what they
thought it was going to require to be effective. After
a meeting on April second three, in which everyone argued
the case for or against Window based on their own calculations,
it was decided that it was worthwhile and that a

(09:30):
request would be sent to the Prime Minister to use
it as soon as possible. The case had to once
again be made to Winston Churchill, with some members of
the British military still in opposition to using Window, but
eventually it was determined that the potential to save lives
was worth the perceived risk of disruption to British and
Allied radar ratings. At the conclusion of the meeting, according

(09:51):
to Jones, Churchill said very well, let us open the window.
R V. Jones, knowing that if the plan for Window failed,
he would take all the heat, sent his men out
to all of the bomber stations where this would be deployed,
to give talks about Germany's night defense systems and clearly
explain how the packets of aluminum strips were to be
deployed and at what rate. As things were finally moving

(10:15):
to actual use of the research that Joan Curran had done,
there were also concerns that Germany was essentially in the
exact same position with a similar radar disruptive technology that
they were fearful about putting into use. After the war, RV.
Jones discovered that Germans had definitely known about Window and
were perplexed as to why it wasn't in use. They

(10:36):
also tried a similar tech of their own, but the
trials went so poorly that Erman Goring had all the
reports related to these tests destroyed. Operation Gomorrah on July
was the first time that Window, the culmination of Kurran's experimentation,
was used in a bombing raid. The first night of
attacks on Hamburg, Germany were considered a success. British forces

(10:59):
sent seven hundred and ninety one aircraft out and they
lost only twelve. That's a one point five percent loss rate.
Similar rates that had happened without the use of window
had a six point one percent loss rate. Jones estimated
that seventy to eighty aircraft were saved thanks to their
parcels of aluminum strips over the course of several raids.

(11:19):
The next night, window was used again on our rate
in Essen. This time the disruption was so significant that
the Germans were not only unable to track enemy bombers,
but they also weren't able to track their own planes.
The loss rate for the British bombers was slightly higher
than the previous night, at three point three percent, but
this was still a substantial improvement over previous missions without window.

(11:41):
There were additional raids on Hamburg in the days that followed,
both by British Bomber Command and by the US. The
average loss rate for British forces was two point eight
percent averaged out over this series of bombings. While we're
talking about the success of these raids, we also have
to acknowledge the heavy civilian casualties that took place in
these attacks. The ground fires created by the bombing on

(12:03):
Hamburg during the second raid, there created a firestorm. The
intensity of the fires created their own wind as hot
air rows and cold air was pulled down very rapidly
that spread the flames, destroying huge swaths of the city
and suffocating people. Additionally, a tornado like effect pulled people
into the blaze even as they tried to flee. R

(12:26):
V Jones's account indicates that Allied forces didn't realize how
devastating these bombings were until after the fact, when casualty
estimates were placed between forty and fifty thousand people. Uh. Yeah,
you will see sometimes even lower numbers and sometimes even
higher numbers there. I will tell you this, this is
the uh one time that research for this show has

(12:49):
ever resulted in me having nightmares. So if you want
to go study this firestorm, please know that the images
you will see are very disturbing. The stories of survivors
are very upsetting. Um. But it's also really important that
we talked about it. So. Jones also acknowledged that this
was something that seemed very counter to what they had

(13:10):
been sort of preaching from the Allied side. He later wrote, quote,
we had started the war morally opposed to the bombing
of civilian populations, and now we were pursuing it on
a horrifying scale. How had this come about? And then
he goes on to discuss how that had been something
of a gradual process as the realizations came that bomber

(13:30):
Command could not always guarantee precision hits to targets, but
also that bomber Command was really the only thing that
was hurting Germany on the scale that was needed to
end the war. Additionally, there was a strategy in play
to demoralize the German population by striking a city filled
with industrial workers. Jones summarized all of this by writing, quote,

(13:51):
it was on the grounds of probable effectiveness and not
of morality that the battle was fought. At one point,
there was even a brief accusation that the Allies had
used chemical warfare at Hamburg, although that was untrue. The
source of this allegation had been some of the aluminum
strips that the Germans had recovered after a cow had
eaten them. It died the strips that have been coated

(14:12):
in a black paint to make them invisible at night,
and that paint did contain a small amount of arsenic,
but not enough to substantiate a claim of chemical warfare.
As another aside, because I suspect people will ask, couldn't
a cow just die from eating those strips? Um, I'm
being grown up the child of farmers. Um. Cows eat
metal all the time because often they're fed stuff that's

(14:34):
just kind of sloughy and filled with all kinds of craziness. Also,
they will sometimes just find things in fields. Some farmers
actually put magnets in their cows stomachs to kind of
keep those things isolated and not passed through their digestive
tract and couse mortality. Um. But yeah, it's not uncommon
for cows to eat metal. Uh. Just the same. Despite
those chemical warfare claims being abandoned, the attacks on Hamburg

(14:58):
and Essen had significantly di and ish both morale and
production of war material. Over the course of eight days,
the British and US bombing raids destroyed half of Hamburg.
While it initially was considered by some to be an
active retribution of the Nazi bombings of London and Coventry,
the difference in the level of destruction at Hamburg made
the ethics of war something that people inside the military

(15:20):
considered in a new way, even as newspapers were touting
Operation Gomorra as a huge win, and even today, these
raids and the balance of moral versus strategic decision making
continue to be discussed. We also talked about that a
lot in our episode on Sadako Sasaki and her Thousand
Cranes and the bombings of Hiroshima and Nagasaki and all that.

(15:42):
So it came up a lot all through the war.
The system that Jones had conceived and that Joan Curran
had tested had worked incredibly well, like keeping German forces
confused as their radar failed to give them information that
they needed to defend against these bombing raids, and as
the Allied forces prepared for D Day, Curran's radar chaft
system was used to obscure the details of the planned

(16:03):
landings at Normandy. It was important to not only hide
the fact that Normandy was their target, but also to
misdirect the attentions of the German forces to another location
if possible. The hope was that the Allies could convince
the Germans that the planned landing was east of the
Sin River, so that they would keep most of their
troops and artillery there. And then the Allied forces would

(16:24):
destroy the bridges that would have enabled them to move
out of that area. So they kind of wanted to
get them in one place and trap them there. And
then to do all this, the Allies needed illusion. They
wanted to convince the Germans that a force was coming
in from the sea, and they came up with a
plan to use Window to do so. Robert Cockburn, who
had overseen the testing that Joan Curran had done to

(16:45):
develop Window, was the person who developed this plan. And
we're going to talk about how that plan was executed
with some very dire results. But we are going to
take a quick sponsor break before we get into that.
On June, the day before D Day, the Lancaster bombers

(17:07):
of the six seventeen Air Squadron flew in orbits eight
miles long and two miles wide, slowly moving southeast at
eight nots to mimic an ocean convoy. According to an
account given to the Royal Air Force in Mayen by
Wing Commander John Bell MBE, who was part of this mission, quote,
while they were flying, there were two air crew in

(17:27):
the rear of each Lancaster, and I was one of them.
We were handed bundles of aluminum strip which we dropped
at approximately three second intervals through the flair shoote. The
strips varied in size and went from small to large
as we approached the French coast, and large too small
when we turned back to the English coast. A green
light indicated when it was time to throw it. The

(17:47):
efforts of the siv Air squadron were part of what
was called Operation Taxable, which played out along the French
coast near Coptante Fair. A second operation which made use
of window own as Operation Glimmer, made it look as
though there was an Allied force crossing a narrow point
of the English Channel. For Glimmer, the two squadron was

(18:09):
tasked with dropping the chaff, and the deception also included
a feint that made it appear that a massive ground
force was moving towards pat Calais. To provide additional support
for this ruse, dummy parachutists were dropped southwest of deep
and Kin in a segment of the plan called Operation Titanic.
All of these efforts combined worked as the Allies hoped.

(18:31):
The Germans could not get a correct analysis of enemy
troop movements and even into the following month, there was
still confusion about whether there was a large ground force
near the city of Calais. Also in June of nineteen
forty four, Sam and Joan Curran were invited to the
University of California at Berkeley to work on the Manhattan Project,
which they accepted. It was during this time that the

(18:52):
pair worked on the development of a scintillation counter to
measure the ionization of radiation. While Samuel Kerran has given
credit for the invention, which is still used today, he
consistently noted his wife's work on the project, and during
their time in California, the Currents had their first child,
and their daughter was born with an intellectual or cognitive disability.

(19:12):
The exact nature of her disability is unclear from the
readily available information, but after the war came to a close,
the Currents moved back to the UK, where Sam had
been offered a position at Glasgow University, and they had
three more children after they returned to Europe, all of
which were sons. Though her work with the war effort
was done, Joan was hardly idle from this point. In

(19:33):
nineteen fifty four, she and Sam met with four other
couples with the goal of setting up an organization to
assist parents of children with learning disabilities. After the first meeting,
they printed a notice in the paper inviting people to
an open meeting and more than three hundred people attended.
This was the beginning of the Scottish Association of Parents

(19:54):
of Handicapped Children, which is an organization that still exists,
although its name has evolved to be Enabled Scotland, which
is a support and advocacy group. Joan Curran continued to
work in support of people with disabilities throughout her lifetime.
Her close ties to academia led her to advocate on
behalf of students with disabilities and work with the Council
for Access for the Disabled. Both Sam and Joan were

(20:17):
really outspoken proponents of the idea that education was something
that should be available to everyone, and this work that
she did was one way in which she carried out
that mission. She also served on Greater Glasgow Health Board
and was part of the Scottish Special Housing Association. At
the end of the nineteen fifties, Sam became principal of
the Royal College of Science and Technology, which gained its

(20:38):
Royal charter and became the University of strath Clyde under
his leadership. During this time, Joan founded and served as
president of the strath Clyde Women's Group. She also established
the Lady Current Endowment Fund for overseas students. In seven,
at the age of seventy one, Joan was finally granted
an honorary doctorate by the University of strath Clyde, so

(21:00):
finally she got her physics degree. Samuel Curran died on February.
A plaque was installed in his honor in Barony Hall
of Victorian Gothic Church at strath Clyde. Joan unveiled the
plaque in a ceremony, although she herself was terminally ill
at the time. At the event, she was told that
a walled garden at the Ross Priory, also part of

(21:22):
strath Clyde, was to be named after her, with the
Joan Curran Summer House to be built there. Joan Curran
died less than a year after her husband on February
and she never had any of her work published, but
her contributions to the war effort, science, and her community
were recounted over and over in her obituaries. Her obituary
in the Scotland Herald open with the paragraph quote it

(21:44):
is difficult to separate the lives of Joan and Sam Curran.
Although they were a very different temperaments, they made a
superb team and partnership and were devoted to each other. Nevertheless,
it is very important and Sam always emphasized this to
note that she was a considerable scientist in her own
right and in the dark days of the Second World War, she,

(22:05):
as did Sam, played an important part in the survival
of this country. Politician Tim Dalyall wrote an account of
his first meeting with Reginald Jones, that person that had
spearheaded the window project, and in that conversation, Jones told
him quote, in my opinion, Joan Curran made an even
greater contribution to victory in than Sam's pretty incredible, it is,

(22:28):
and it's one of those things. I'm glad there have
been some efforts in both Wales and Scotland over the
last probably five to eight years, of people who are
pointing out like this is a person that we should
be recognizing more than we do. And I love that
they're doing. That makes me happy. Um, I have so
much listener mail. Well, we have just come off of

(22:52):
the holidays, and we are lucky enough to often get
some really really lovely UM cards from our various listeners,
and I want to to read a couple of them
and then talk about one wonderful gift that arrived that I,
of course i'm in love with. The first one is
from our listener Rebecca, who just sent us a lovely
card that is a Doctor SEUs card and says thank
you for all your hard work on the podcast. I'm

(23:12):
a big fan. I also love the behind the scenes
Merry Christmas. UM. Thank you so much, Rebecca. We are
long past Christmas at this point, but I hope yours
was great as well. We also got a card from
uh Test, Bill, Pippy and Buster. Test wrote Holly and Tracy,
happy holidays in a very merry Christmas to you and
your families. I'm a longtime listener to the show, along
with my two cats, Peppy and Buster, who are so

(23:34):
stinking cute. I kind of can't deal with it. That's mine, Uh,
she's my boyfriend. Bill doesn't quite get the whole podcast thing,
but that is his loss. I am going to Rome
in January, so I won't be able to go with
you two in May bummer, but I still get to
go to Rome, so no complaints. Keep up the good work,
um she can, she can pre screen it for us
and tell us all the good places to eat. That's
officially your job now. Our last one is from our listener, Shelly,

(23:58):
and she writes, Dear Holly and Tracy, I am a
total space flight nerd, and I loved every bit of
the Apollo eleven fifty at the anniversary celebrations this summer,
including your fascinating Thomas Harriet and John Wilkins episodes. I
got to see the Columbia command module at Seattle's Museum
of Flight, and I highly recommend it to anyone who
has the chance to see it. I think it's back
at the Smithsonian now as part of the Museum of

(24:19):
Flights UH Destination Moon events. I attended a great talk
by an astrobiologist titled Life on the Ancient Moon conclusion
there could have been some and I picked up these
moon photo postcards to send you. I'm glad I didn't
get around to sending them right away, because I then
saw the build an Orbiter postcard on a more recent
visit to the museum, and I could not resist getting
it as well. Thank you for all the wonderful work

(24:39):
you do on the podcast. I'm always rooting for more
episodes on the history of science, space exploration, and women
in stem. Yeah. So it's this cool kind of snapped
together orbiter model that you can make and it comes
in a postcard and it's really cool and I love it.
I also will echo her thing. If you ever get
to go see any of these marvelous orbiters, please do it. Um.

(25:05):
If you go to Kennedy and you see the Atlantis
on display, that is one of the most beautiful and
moving museum installations I think I have ever seen in
my entire life. Um, it is so good. I stood
there and cried for like forty five minutes. Um. But
I also just recommend that you go and and recognize
the amazing things. The thing I always love about space,

(25:27):
and I try to explain this to people, like when
I look at things like the James Webb's based telescope
or any of the space shuttles, etcetera, is that to me,
what makes them beautiful is that they are the best
of us. Those are a lot of different people from
different backgrounds who have all worked really, really hard and
come together to make something that transcends our life on Earth.
That is why I'm such a space store. Uh. If

(25:48):
you would like to write to us, you could do
so at History Podcast at i heart radio dot com. Again,
that is a newish email address. You can also find
us across social media as missed in History. UH. If
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like you to do that as well. It's a great
way to start the new year. You can do that
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(26:14):
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