Its fellow commanders have blown up all other bridges on the western edge of the Ukrainian capital to slow down Russian tanks.
In the city of a still a stream spreads bilogorodka Leads to leafy villages that were once full of summer cottages and are now a war zone.
The historic city of Kyiv would be effectively cut off from its western hinterland if Casper was ordered to blow up the bridge.
“We will do everything we can to keep it standing,” the former paratrooper told AFP on Sunday.
But the fight is drawing to a close and the mood is getting worse among the Ukrainians erecting the barricades.
Russian warplanes have joined ground forces and are bombing nearby villages and towns.
The flood of people running for safety is never taking its name to stop.
And the rare hours of silence between battles worries Ukrainian soldiers that the Russians are simply reloading for an even more brutal push.
Casper sees a Ukrainian surveillance drone buzzing on the frontline and admits that the time may soon come when he is forced to break the final link to the western lands of Kyiv.
“If we get an order from above, or if we see the Russians moving, we will blow it up,” he said.
“But we will make sure that we do this by sinking as many enemy tanks as we can.”
The borders of Ukraine’s capital are shrinking and its roads are becoming more dangerous and deserted by the day.
Another Russian push on the east bank of Kyiv’s Dnipro River has seen some forces coming within about 50 kilometers (30 mi).
But the West offers Russians a more direct route to the heart of Kyiv and its prized government district.
Some of the city’s residents – almost equally defiant but increasingly serious – are preparing for guerrilla warfare.
The owner of auto repair shop Oleksandr Fedchenko is one.
38 years old was the host UkraineThe most popular weekly TV show about cars in your spare time.
But he has turned his vast garage into an underground weapons manufacturing center, intended to give some strength to Ukraine’s widely defunct volunteer units.
“When the war started, everything changed,” said Fedchenko.
“We found that our regular mechanics knew how to make weapons. Others knew how to make a Molotov cocktail. We’re doing absolutely everything we can.”
All the employees of Fedchenko’s repair shop have changed their grease-stained overalls for the olive uniforms of the Volunteer Units of Ukraine.
A mechanic-turned-volunteer fighter who had adopted a nom de guerre “cross” was soldering a large-caliber machine gun that Ukrainian soldiers had previously captured from a captured Russian tank.
Vishal, 28, was trying to cut down a gun and turn it into a handheld weapon that an untrained volunteer might be able to use on the streets.
“This thing might not be a very straight shoot, but at least it’s something,” Kraus said, and gave his balaclava a reassuring tug.
“Many people don’t know that we do this and it may not be very legal,” he said.
“But when there’s a war, what’s legal doesn’t matter – only our national defense.”
Fedchenko’s voice broke and his eyes lit up as he recalled life before Russia’s invasion of Ukraine on February 24.
“I felt helpless. Stick a Kalashnikov in my arms, and I wouldn’t last 10 minutes. But I needed to do something,” he said.
Their makeshift weapons manufacturing plant is badly affected by the Russian missile attack.
On the road marking the westernmost point of Kyiv sits the spacious garage. Several similar industrial buildings along the same route now stand in ruins.
“Each of us knows that we can be attacked at any time,” Fedchenko said.
“Each one of us knows this might be our last day. And yet we come.”
There were also tears running down the cheeks of Galnichenko singing the pensioner.
The 64-year-old walked out alone from the fields marking No Man’s Land between Casper and the bridge overseeing Russian-occupied villages.
“I don’t know where my kids are,” she said in a trembling voice. “I can’t reach them by phone.”