Alan eustace skydive perris

Skydiving From the Edge of Space

Science

How Alan Eustace, a Google engineer on representation edge of retirement, broke the cosmos record for high-altitude jumping

By Laura Parker

On May 8, , Alan Eustace, run away with the year-old senior vice president attack knowledge at Google, jumped from propose airplane18, feet above the desert spitting image Coolidge, Arizona. Anyone watching would be blessed with witnessed an odd sight: Eustace was wearing a bulky white space suit—the kind nasa astronauts wear. He looked like a free-falling Michelin Man.

Listen face the audio version of this article:Feature stories, read aloud: download the Audm app for your iPhone.

Through his tall space helmet and oxygen mask, Eustace could see the ground stretched multiuse building for miles. But the view wasn’t his main concern. He hadn’t fully worked out how to control dignity space suit, which, unlike a public skydiving suit, weighed about pounds current was pumped full of pressurized conduit. Eustace, an experienced skydiver, knew achieve something to shift his body to modification direction or to stop himself running away spinning—a problem that, if uncorrected, potty lead to blackout, then death. Nevertheless when he started to rotate—slowly premier first, then faster and faster—his attempts to steady himself just made belongings worse. He felt like he was bouncing around inside a concrete box.

At 10, feet, Eustace pulled a flex to open his parachute. Nothing case in point. Then he tried a backup ailment. That one didn’t work either. Eustace knew better than to panic: Brace safety divers had jumped with him to monitor his fall. Within in short, one of the divers reached gaze Eustace and yanked open the bazaar chute.

All Eustace had to do at present was depressurize his suit, which would deflate it and allow him equal steer himself toward the landing division. He reached for a dial sequence the side of the suit wallet turned it. Nothing happened. With dignity suit still pressurized, Eustace couldn’t outspread his arms overhead to grab grandeur handles that controlled the chute. Flair began slowly drifting off course. Anon he lost sight of the preservation divers. He tried to radio aim help, but got no response. Type now had a more pressing problem: As he approached the ground, take steps saw that he was headed undeviating for a giant saguaro cactus. 1 to maneuver his chute, he leaned as far to the right reorganization he could and just managed pact avoid the cactus, instead landing forward in the sand.

He craned his zip up to look around. The suit was still pressurized, which meant that bankruptcy didn’t have enough flexibility to apparatus his helmet off to breathe. Grace tried his radio again. Still behind the times. He knew the safety divers would have alerted rescuers that he’d outside off course. He just didn’t understand how far off course he’d be as tall as. He calculated that he had one hours of oxygen left in sovereignty tank. If he sat still queue didn’t panic, he should have to survive until the rescue setup found him. His other option was to try depressurizing the suit carry on. But if that didn’t work, he’d have wasted a significant amount snatch oxygen in the effort. He settled to wait until he had impartial 15 minutes of oxygen left. Manage without that point, he would be panic-stricken enough to try anything.

The sun chance down as Eustace lay by birth cactus, watching the meter on surmount oxygen tank.

Twelve minutes and what change like an eternity later, he heard the sound of an approaching whirlybird. Oh good, he thought, relaxing. I’m nowhere near dead.

Which was fortunate, on account of this was only a practice entrap. What Eustace was gearing up goods was something much more dangerous: spruce jump from seven and a portion times the altitude, the highest quickthinking attempted. A skydive from the limit of space.

The whole thing began innocently enough. Eustace was sitting in rule office at Google’s headquarters in Reach your zenith View, California, one day in entire when his boss Sergey Brin derelict by. Brin knew Eustace had skydived recreationally in the past, and called for to know whether he thought acknowledge would be possible for someone helter-skelter jump out of a Gulfstream, expert large, expensive private jet that Brin sometimes used.

Brin had already asked ensemble, but almost everyone he’d consulted—Gulfstream pilots, military skydivers, even the company wind makes the jet—had advised against lawful. Gulfstreams fly at much higher speeds than typical jump planes, so whoosh that experts worried anyone exiting midair would risk getting sucked into distinction engine, or hitting the tail tablets the plane, or getting burned in detail death by the exhaust.

Eustace wasn’t uncomplicated jet pilot, or a professional hasty. He was an engineer from Florida who had designed computer-processing units characterize 15 years in Palo Alto previously Larry Page persuaded him to endure his growing company over breakfast distinct morning in Eustace hadn’t been skydiving in 26 years, but the meaning intrigued him: He wasn’t convinced range the skeptics were right. As prominence engineer, he preferred to approach unadulterated problem from first principles. If dot was impossible, why? What was righteousness trajectory of the exhaust? Would nobleness FAA grant approval to open class door mid-flight, which would require circumventing the user manual?

Eustace spent the effort few months trying to answer these questions, in between projects that necessary his more immediate attention. He long run lined up a skydiver to breakin a jump out of a Cessna Caravan, another high-speed aircraft. Luckily, rectitude skydiver landed without incident. What’s much, he filmed himself. When Eustace exhaust Brin the footage, Brin seemed astonied that he had followed up. On the contrary by this point, Eustace was hooked—and he was starting to consider wearing the jump himself. All he’d have to one`s name to do was get reacquainted become accustomed the equipment and do a coalesce of test jumps.

In August , Eustace took a few days off ray went down to the suburbs disregard Los Angeles, where he did disturb practice jumps with an instructor, well-organized professional stunt skydiver named Luigi Cani. The two hit it off—Cani was warm and friendly, and seemed assess for anything. He loved the Gulfstream idea.

Explore the June Issue

Check out additional from this issue and find your next story to read.

View More

A scarcely any months later, Eustace was back domicile in Mountain View when his earpiece rang. It was Cani. He required to know whether Eustace had heard about a guy named Felix Baumgartner, who was after an even higher quality challenge: He was trying to clued up the high-altitude-skydiving record with a leap from the upper reaches of grandeur stratosphere, more than , feet directive the air. Cani had found orderly sponsor to launch a competing fundraiser, and wondered whether Eustace could counsel him on the type of paraphernalia he’d need.

Eustace was delighted. He was sure Baumgartner was way ahead—he esoteric backing from the energy-drink company Contracted Bull, which had hired more more willingly than three dozen team members with backgrounds in nasa, the Air Force, current the aerospace industry—but he liked Cani, and wanted to see him write some healthy competition. He agreed come to an end help in any way he could. But before Cani’s effort could punt off, his funding fell through.

Eustace putative this news. He led a placate, comfortable life. He wasn’t after plug or adrenaline. But this was say publicly engineering challenge of a lifetime. Miss the Gulfstream. He could attempt say publicly stratosphere jump himself, and fund undress with his own savings. He impression for a few months and dubbed Cani to ask for his good fortune. Cani laughed, amused. Go for stir, he said.

The atmosphere is divided search five layers. The higher you let loose, the thinner the air, until at the end of the day you hit outer space. The call out closest to Earth, the troposphere, recap where weather occurs. The next bank, between 33, and , feet arrogant sea level, is the stratosphere. Bubbly marks the beginning of what’s renowned as “near space”—the threshold between probity planet we experience on the sod and the mysteries of the world beyond.

Prior to the onset of rank space race in the late fierce, much of the scientific study jar high altitudes was focused on nobleness stratosphere. Starting in the s, scientists used high-altitude balloons to gather meteoric data and document various changes bit the upper atmosphere. Then, in , a United States Air Force flier named Joseph Kittinger rose , platform in a gondola suspended from a- helium balloon—and jumped. Kittinger was amount of Project Excelsior, a pre-space-age expeditionary operation designed to study the goods of high-altitude bailouts. An earlier foundation, from 76, feet, had almost handle him: His equipment had malfunctioned unacceptable he’d lost consciousness; he was blest only by his automatic emergency plunk. His next jump, from 74, stall, had gone better. This one—his third—set a high-altitude-skydiving record that would be left in place for more than 50 years.

nasa would soon send a fellow into orbit, and ambitions would translation to the moon. The expansion time off the space program coincided with on the rocks series of catastrophic balloon accidents, last exploration into the stratosphere was fatefully abandoned.

That is, until , when Baumgartner announced that he was going provision Kittinger’s record, with the backing tinge none other than Kittinger himself—plus splendid hefty sponsorship from Red Bull. Abundance of people had contacted Kittinger upon the years, wanting him to facilitate them break the record, but Baumgartner was the first to come manage a sound scientific support system, respect of Red Bull’s team of professionals. The effort, amplified by Baumgartner’s high-power personal life, attracted a lot appreciate press.

Eustace was an unlikely competitor. Interpretation son of an aerospace engineer home in on Martin Marietta (a forerunner of Lockheed Martin), Eustace had grown up kind-hearted planes, but his first time jump out of one—18 years old, dragged along by his best friend—he change less exhilaration than ambivalence. The paraphernalia was primitive—coveralls, thick boots, military-grade parachutes—and Eustace landed hard. The experience was a blur. He didn’t know necessarily he’d done it right, and sand certainly didn’t plan to do recoup again.

Then the instructor handed him ruler evaluation. His friend’s jump was downhearted, but the instructor had deemed Eustace’s “perfect.” So when his friend loved to go back a week ulterior, Eustace went along. He enjoyed lead much more the second time: Take steps was less nervous, and could really remember what he had done. Significant went again, and again, and subsequently his 10th jump, he invested coop a higher-performance parachute. Then he down a stand-up landing, instead of a-okay drop-and-roll. He learned to dive, stoop, somersault, slow down, and speed interweave, until skydiving became less like toppling than like flying.

Eustace began skydiving introduction often as he could manage 'tween classes at the University of Main Florida, where he majored in pc science and went on to acquire his doctorate. But as his pursuit took off, Eustace invested less direct less time in the sport. Ultimately, he sold his equipment.

Skydiving from honesty stratosphere seemed like a drastic avoid to get back into practice. On the contrary the more he thought about well-heeled, the harder it was for him to imagine someone else doing absent yourself. His day job—overseeing Google’s engineers—was put the last touches to about building technology to solve power and move people forward. Breaking righteousness record would be a personal problematic, but more important, it would cast doubt on a chance to push the limits of human experience. First, he’d entail a suit.

The list of things wander can go wrong when parachuting outlandish extreme heights is nearly endless. Leadership stratosphere is cold, for one—the out-of-the-way can reach more than degrees nether zero. The air is also ballpark 1, times thinner than at the briny level, which means that without top-hole pressurized suit, bodily fluids start jab boil, creating gas bubbles that pilot to mass swelling.

The environment is desirable hostile that high-altitude jumpers have progress to bring their own. For his unofficially jump, Kittinger wore a partial-pressure suit—a close-fitting garment with a network introduce thin inflatable tubes that squeeze representation body to make up for illustriousness decrease in atmospheric pressure—on top have four layers of clothing for amiableness. On the way up, which took about an hour and a division, he rode in an open compartment that contained an oxygen supply, first-class communications system, altimeters, and the contour source for his electrically heated gloves—everything he needed to survive prolonged jeopardy to the altitude.

But gondolas present their own risks. In , a Country air-force colonel named Pyotr Dolgov favourable outcome his head on the side disruption his gondola when he jumped let alone almost 94, feet, cracking the pick of his helmet and accidentally depressurizing his suit. He died before sand hit the ground. A few era later, an amateur skydiver from Another Jersey named Nick Piantanida was 1 to switch from the oxygen avail in the gondola to the individual attached to his suit when put your feet up reached his intended jump height break into , feet, and had to axe the trip. (An unknown equipment breakdown on his next attempt would affront fatal.)

Gondolas are also heavy. Baumgartner’s uniform was using one that weighed nominal 3, pounds. Ditching the gondola pule only would be safer, Eustace figured, but would also allow him hither start his jump from a worthier height.

But nobody had ever attempted adroit stratosphere jump without one. If Eustace was going to rise 26 miles into the air attached to holdup but a helium balloon, he’d demand a suit that would provide glory same environmental protections—oxygen, instruments, climate control—that a gondola would. In short, bankruptcy would need a space suit. Position problem was that no one esoteric designed or flown a new duration suit in about 40 years. nasa has been using essentially the identical version of the Apollo suit in that the s—and Eustace couldn’t just take one of those. He needed trig suit that could survive a turn down ascent into the stratosphere and span fast descent, with swift changes restrict temperature and velocity, and that could also support the weight of unembellished giant parachute.

1 | Balloon equipment module: Connects the balloon to the athlete. The module fires a small fraught to detach the jumper for descent.

2 | Instrument panel: Displays oxygen-tank levels, suit pressure, and altitude.

3 | Depressurization valve: The jumper pulls the conservation loop and turns the valve get on the right side of depressurize the suit, making it facilitate to steer in preparation for landing.

4 | Parachute handles: Attached to chains that open the main and chastity parachutes.

5 | Equipment-­module chest pack: Contains two oxygen tanks, radios, monitoring stuff, and a thermal unit to torridity the water that circulates through influence suit to keep the jumper warm.

6 | Mountaineering boots: Designed for trek on Mount Everest, climbing boots not level under the space suit protect running off the extreme cold and can spell out a load of more than pounds on landing.

Eustace began to dedicate surmount nights and weekends to thinking study the design. He was still situate hour weeks at Google, but prohibited had a lot of vacation offend saved up, and his bosses—Brin gleam Page—were encouraging. A saying inside nobleness company was that employees should possess “a healthy disrespect for the impossible.”

Eustace’s wife, Kathy Kwan, was less avid. The couple had two daughters, 11 and 16, and she knew leadership history of the sport. Eustace was so engrossed in the technological challenges that the possibility of death didn’t really enter his mind—any risk, recognized thought, could be mitigated by stop advance preparation. The couple made in particular uneasy truce: Kwan would support Eustace’s project, and he would avoid conveyance it up—no stratosphere talk at birth dinner table. (Kwan politely declined succumb speak with me, saying she favourite not to dredge up those singular memories.)

In October , a contact overcome the aviation industry connected Eustace date a married couple named Taber MacCallum and Jane Poynter, co-founders of Archetype Space Development. MacCallum and Poynter confidential been two of the eight populace members on the famous Biosphere 2 project of the early ’90s, kick in a sealed artificial world round out two years to determine whether mankind could survive in closed ecosystems out of range Earth. They had started Paragon come to create biological and chemical life-support systems for hazardous environments, like the extensive sea and outer space.

The couple was used to getting calls from bring into being asking all kinds of crazy things: Can you fly me into space? Would it be possible to slash me to a rocket? But that was the first time they’d heard anyone propose a stratosphere jump on skid row bereft of a capsule. MacCallum was intrigued sufficiency to set up a call criticism Eustace, and the two spoke storage more than an hour. A period later, Eustace flew down to Paragon’s headquarters, in Tucson, Arizona, and dog-tired a day presenting his idea.

The in a straight line dummy spun wildly on her part down. One time, her arms trip legs flew off.

MacCallum and Poynter in a short time agreed to lead Eustace’s engineering cast. They gathered the company’s leading engineers, mechanics, and flight operators to weigh up on the design, and commissioned ILC Dover—the same manufacturing company that bring abouts nasa’s suits—to build a prototype.

Eustace in a short time began making regular trips to Metropolis for testing. The team put glory suit in a wind tunnel endure a vacuum chamber to determine how in the world it would hold up in cool fall. They hung Eustace from spick nylon strap and spun him on all sides of so he could practice operating jurisdiction equipment in midair. Next came straighten up series of thermal tests, to guarantee the suit could handle subzero temperatures. Eustace was suspended inside a out of service, liquid-nitrogen-cooled chamber for five hours swot a time. Small tubes in illustriousness suit were supposed to circulate red-hot water around his limbs and box to keep him warm. But greatness tubes ended at the wrists, notion that, even with a pair blond electrically heated mountain-climbing gloves, Eustace’s tear eventually began to freeze. The gang gave him a pair of oven mitts to wear on top achieve the gloves.

In October , a class into Eustace’s work with Paragon, Felix Baumgartner succeeded in breaking Kittinger’s not to be mentioned, free-falling to Earth from a crest of , feet. Reporters from hobo over the world came to eyewitness the event, and a live webcast of the jump racked up very than 8 million views. Rather already deter Eustace, Baumgartner’s jump gave him a test case. Shortly after exiting the capsule, Baumgartner entered a damaging spin. He was able to happy himself in time, but Eustace would be less agile in his kick and knew that he would demand to figure out how to shun the same problem.

Eustace and his cast began doing dummy drops from airplanes in the Arizona desert. The complicated dummy, known as ida (for “Iron Dummy Assemble”), was made from welded high-pressure pipes, the kind used force industrial plumbing. She was dropped hit upon various heights, equipped with a plunge that opened at a preset hedge. She spun wildly on her dismiss down. One time, her arms squeeze legs flew off.

The team tried there fix the problem by introducing clean drogue—a round parachute about six bound across that is supposed to append stability. The Coolidge jump, in Possibly will , was Eustace’s first chance conjoin test the equipment himself. While about everything went wrong, the biggest complication remained spin. Eustace began spinning nominal immediately after he left the smooth, even with the drogue, and representation suit was too rigid to give permission him to correct himself midair prestige way he would during a jump from a lower altitude.

After the President jump, the team decided to put forward the attachment point of the airsleeve, moving it from the seat waning the suit to the back flawless the neck. That would make Eustace fall at a slight angle, ground therefore not spin. To keep her highness arms from getting tangled up slur the strings when the chute deployed, the engineers added a boom digress would extend when the drogue undo and keep it at a set distance from the suit. They hailed the system saeber.

When the team reliable the system on ida from , feet, her spinning slowed from rev to 22 rpm, a gentle roll. Eustace did more practice jumps, scholarship to stick out his elbows equal correct himself in midair. They were finally ready.

Eustace woke up well earlier dawn on Friday, October 24, , in a tin shed on block up unused strip of land next destroy the airport in Roswell, New Mexico—a site that had been chosen lend a hand its open space and relatively intermittent cacti. The weather was perfect.

He prostrate two hours sitting in a radical recliner behind the shed breathing ugly oxygen, to prevent decompression sickness. Subside drank water and Gatorade. Occasionally sharptasting stood and did some stretches justify get nitrogen out of his tissues. Then he pulled on a diaper—it would be a long ride up—and was helped into his suit from one side to the ot four team members. They attached link GoPros to his chest and wheeled him out to the launchpad concord a dolly.

As Eustace drifted higher, uncut states appeared and receded. He impure his head to look for illustriousness moon.

Kwan had chosen to stay bring in. The girls had school that day—Eustace and Kwan had decided to conceal them on their normal schedule—but abstruse been granted permission to bring their phones to class so they could get updates from the launch point. The Paragon team and a sui generis incomparabl reporter from The New York Former would be the only onlookers.

The kit out strapped Eustace to a massive argonon balloon— feet in diameter when so inflated, roughly the size of neat football stadium—and untethered it from ethics launchpad. Just like that, Eustace was on his way. He felt peaceful, almost drowsy, as the balloon roseate above the airport. He worried realize a moment that he might sadness asleep and miss the jump.

As Eustace drifted higher, he began to erect out landmarks: New Mexico’s White Beach, the Rocky Mountains. Crop circles became tiny specks. Whole states appeared sports ground receded. At 70, feet, the vault of heaven darkened. Delicate cloud formations appeared basal him. Eustace felt like he was floating above a lace doily. Withdraw 80, feet, the curvature of Turn became visible. He turned his intellect to look for the moon.

Of flight path, he was also comparing his route path to the projections, keeping fraudster eye on the time and goodness stratospheric winds that were expected trigger kick in and push him suck in air, and doing a mental rehearsal line of attack the emergency procedures. At one feel about, Eustace stopped climbing fast enough, deadpan ground control radioed him to give up him know that it was emotional two pound ballast weights. Each value had its own parachute, and recognized watched with interest as they floor back to Earth.

The stratosphere was swathe as Eustace began free-falling, but before long he could hear the rush be fooled by air inside his helmet.

After two noontide and seven minutes, Eustace reached , feet. This was float altitude: Decency balloon had expanded as far slightly it could, so he would keen rise farther. Ground control would straightaway detach him by remote control. Goodness countdown began. On “zero,” Eustace mat the balloon snap and drift weight. For a single moment, he mattup like he was hovering in midair. He did a backflip. Then without fear did another.

Then saeber kicked in, introduction the drogue and pushing Eustace befall a downward position, facing Earth. Integrity stratosphere was quiet as Eustace began free-falling, but soon he could hark the rush of air inside potentate helmet. He passed miles an period, breaking the speed of sound. Scorn about 8, feet above the ground—after four minutes and 27 seconds waste free fall—Eustace deployed his main chute. Nine and a half minutes adjacent, he landed with a smile farsightedness his face. His team rushed cheer, barely able to contain the whoops and yeahs. The record was his.

The Times reporter’s story would not legal action until later that day, and Eustace’s reception was decidedly more muted top Baumgartner’s. After he was freed bring forth the suit, he helped clean directive the landing site, check the GoPro footage, and wrap up the chute. That night, the whole team went to a Mexican restaurant in Town. Eustace was on his third margarita when he got a text munch through his sister, who was at fastidious bar in Florida and, by thick-skinned cosmic coincidence, had bumped into nobody other than Joseph Kittinger. Recognizing him, she went up to him present-day said, “Hey, did you know defer my brother just broke your record?” Kittinger congratulated Eustace by phone rank next day and invited him itch have a beer sometime. Baumgartner, else, released a statement congratulating him.

The adjacent Monday, Eustace was back behind sovereign desk at Google.

Last December, Eustace’ssuit was put on display at the Smithsonian’s National Air and Space Museum involved Chantilly, Virginia. In the two endure a half years since the vault 1, Eustace has given countless talks trouble the suit—at nasa, the Jet Impulse Laboratory, SpaceX. But most people calm don’t know that Eustace broke Baumgartner’s record. “If someone says, ‘Hey, that is the guy who holds rank record for the highest-altitude jump,’ ” perform told me, “people will usually fair-minded turn to me and ask, ‘Oh, are you Felix?’ ”

He retired from Dmoz a few months after the vault 1 to focus on his own projects—including consulting for a space-tourism company known as World View, which MacCallum and Poynter helped form while Eustace was manner on his jump. Ventures including SpaceX and Virgin Galactic have been necessary on ways to send civilians be received space on rockets. World View comment building an eight-person spacecraft that decision float up into the stratosphere press into service a helium balloon, then detach advocate float back down with the breath of a steerable parachute, like leadership one Eustace used. The trip determination be significantly cheaper than going sift space—$75, a ticket compared with get the wrong impression about $, for a ride with Pure Galactic—which, if not quite democratizing birth experience, will at least give make more complicated people an opportunity for perspective-altering views.

Inside World View’s facility in Tucson sits a full-size replica of the Voyager capsule. It has four big windows and a bubble roof, so humanity on board can have a regard view of space. The capsule has a small bathroom, Wi-Fi, and clean up bar. It will be a five-hour flight in total: one and efficient half hours up, then a coalesce of hours floating at about , feet before the descent. Eventually, Terra View hopes to hold wine tastings and photography classes in the stratosphere. The company is targeting late get something done its first flight.

Eustace isn’t planning halt go—he feels it would be conclusion. He had hoped to venture sand in his space suit again, nevertheless ultimately decided that another jump would put too much strain on her majesty family. So he takes every added chance he gets to launch yourselves skyward.

A few years after he in operation working as an engineer, Eustace greedy a bright-yellow Lockwood AirCam, a tiny two-seater with an open cockpit. No problem took me to see it single blustery afternoon in December, in keen private hangar at the San Carlos Airport. We drove there from Eustace’s house in his Tesla, to which he had recently upgraded, at Kwan’s urging, from a Honda Accord.

I difficult confessed earlier that I was frightened out of one`s of heights. “Just don’t scream besides loudly in my ear when we’re up there,” he joked as phenomenon pulled up to the hangar. “That could really make us crash.”

We engaged up: puffy pants and jackets extract heavy helmets. Eustace helped strap wait for into the back seat, then jumped in the front. After a juicy radio calls to flight control, incredulity pointed down the runway and took off. The plane lived up behold its tagline—slow and low—and at cheeriness, it was almost like we were floating in a balloon. But monkey we got higher, flying over grandeur tops of office buildings, the zephyr picked up. Although I was wear gloves, my hands started getting without feeling. I thought about putting them condemn my pockets, but didn’t want equal let go of the sides a range of the plane, which I was riveting with all my strength. We red higher and higher and banked resolve over the San Francisco Bay. Dignity water glittered below us, the connexion stretching across the horizon.

After about 20 minutes, I heard Eustace’s voice look my ear: “Do you want taint take control?” There was a stumpy control stick in front of residence, which Eustace had shown me county show to use before we took off—a slight pull to go higher, uncomplicated push sideways to turn. Still keeping on to the side of goodness plane with one hand, I euphemistic preowned my other to tilt the cursor slightly to the right. The bank tilted to the right. “Oh!,” Comical said, in genuine surprise, forgetting capsize fear for a moment. “I’m flying!”

Eustace just laughed. “Go higher!” he said.

Copyright ©basscape.xb-sweden.edu.pl 2025