Anniversaries: 50 years of human spaceflight – 30 years for Shuttle

by Chris Gebhardt

April 12, 1961: Yuri Gagarin launches into orbit aboard Vostok 1 to become the first human being to travel into space. April 12, 1981: Space Shuttle Columbia proudly soars into the early-morning sky over Central Florida to a) become the first-ever reusable spacecraft, b) the first spacecraft to launch like a rocket and return like a plane, and c) inaugurate the Space Shuttle Program – a program that has served manned space exploration for 60 percent of these past 50 years and has been responsible for launching more humans into space than any other vehicle.

Vostok 1/Yuri Gagarin: How it all began…

Fifty years ago today, at 0607 UTC, 0107 EST, the age of manned space exploration began with the highly-secretive and highly successful launch of Soviet cosmonaut Yuri Gagarin (then only 27 years old) and the Vostok 1 mission from what is now Baikonur Cosmodrome (formerly Tyuratam) in present-day Kazakhstan (formerly Kazakh Soviet Socialist Republic).

With the launch of Gagarin came an era that many believed to be impossible. Not even 60 years earlier, mankind had yet to make the first powered flight of any kind, and after that, many thought the sound barrier to be impenetrable.

But Gagarin’s launch and mission proved that mankind could not only travel by rocket into Earth orbit, but survive the journey.

As such, the road to Vostok 1 was made possible by numerous tests and proofing of the Vostok rocket’s capability.

Derived from the Soviet R-7 Semyorka ICBM (Intercontinental Ballistic Missile), the Vostok rocket was designed as both a manned and unmanned launcher.

Of the six Vostok rocket designs, Luna 8K71, Vostok-L 8K72, Vostok-K 8K72K, Vostok-2 8A92, Vostok-2M 8A92M, and Soyuz/Vostok 11A110, only the Vostok-K 8K72K was used for the manned spaceflight missions in the early 1960s.

Naturally, Gagarin’s flight on Vostok 1 was preceded by numerous test flights designed to prove the Vostok rocket’s overall reliability leading up to the first manned flight.

Conceived of during the heart of the space race between the United States and the USSR, the Soviet’s chief rocket designer, Sergei Korolev, understood that the United States would have the ability to place a man into space on a suborbital trajectory by as early as January 1961. The goal was then set to have the USSR not only beat the US into space, but to place a Soviet into Earth orbit on the very first manned mission.

By April 1960, Korolev and his team had designed three Vostok spacecraft dubbed Vostok 1K (a test vehicle), Vostok 2K (a spy satellite), and Vostok 3K – the design for all six manned Vostok missions.

The Vostok rocket family was also proceeding in development at this time. On May 15, 1960, the first Vostok spacecraft, called Korabl-Sputnik 1 (because the name Vostok was still classified at the time), was launched into orbit. Initially a great success, the spacecraft’s thrusters malfunction on orbit 54 and sent the craft into a higher-than-planned orbit.

The next six Vostok spacecraft launches all carried life-support equipment, heat shields and de-orbit capability.

Flown between July 28, 1960 and March 25, 1961, three of the six flights were successful, with one partial failure and two total failures. The first mission exploded shortly after liftoff, but the second mission was a success. During that mission, two dogs became the first living beings to be returned safely from Earth orbit.

The last two flights (both completely successful) in the test series used an automated version of the Vostok 3K spacecraft – the craft to be used for Gagarin’s flight. Both missions simulated Gagarin’s flight, lasting only one orbit and just over an hour and a half.

The last test flight was launched just 18 days before Gagarin’s flight.

With the test flights complete, final preparations began for the first manned flight on Vostok 1. On April 8, just three days before flight, the crew for Vostok 1 was selected. Yuri Gagarin, the favored candidate, was official assigned as the primary crewmember for the flight. Fellow cosmonauts Gherman Titov and Grigori Nelyubov were selected as primary and secondary backups, respectively.

On April 11, 1961, the Vostok-K rocket with the attached Vostok 3KA spacecraft was rolled out to the launch pad. A final inspection of the vehicle was conducted in the horizontal position before it was erected into its vertical launch position.

At 0530 Moscow time on April 12, Gagarin was awakened, ate breakfast, donned his spacesuit, and was transported to the launch pad. Gagarin entered the Vostok 1 capsule at 0710 local time, 0410 UTC (2310 EST April 11 in the US).

An initial attempt to seal the hatch for flight failed, the hatch was unbolted, repositioned, and re-bolted & sealed for flight.

One hour 57 minutes after Gagarin boarded the vehicle, the Vostok’s engines roared to life, and at 0907 local time, 0107 EST, Vostok 1 lifted off from what is today known as Baikonur Cosmodrome Site No. 1.

Propelling Gagarin into Earth orbit, the Vostok-K rocket was comprised of three stages. Stage 1, which included four (4) strap-on boosters, carried a gross mass of 43,000 kg, a thrust in vacuum of 99,000 kgf – or 971 kN per engine (there were four engines total), and stood 19 meters in length and 2.68 meters in diameter with a span of 8.35 meters. The four RD-107-8D74-1959 engines (one per booster) burned a combination of LOX (Liquid Oxygen) and Kerosene and burned for 118seconds.

The second stage, defined as starting at the time of strap-on booster separation, was powered by a single RD-108-8D75-1959 engine burning LOX and Kerosene at a thrust of 912 kN. This engine was ignited on the ground prior to liftoff and burned for a total of 301seconds. The Core stage was 28 meters long and 2.99 meters in diameter.

The third and final stage of the rocket, defined as the time period starting with Stage 2 separation, used one RD-0109 engine burning LOX and Kerosene for a thrust of 54.5 kN in a vacuum. The engine, ignited after Stage 2 separation, burned for 365seconds. The stage, which directly delivered the Vostok 1 spacecraft into orbit, was 2.84 meters tall and 2.56 meters in diameter.

All three stages the Vostok-K rocket functioned nominally and delivered Gagarin and Vostok 1 into Earth orbit at 0617 UTC (0117 EST). Ten minutes after launch, Gagarin officially became the first person to achieve orbital velocity and began his historic trip around the Earth.

At engine cutoff, Vostok 1’s orbital inclination was 64.95-degrees with an apogee of 203 miles and a perigee of 105 miles.

Despite a perfect performance by the Vostok K rocket, it would take flight controllers 25 minutes to confirm that Gagarin was in a safe and stable orbit.

At 0625 UTC, Gagarin began his northwest to southeast crossing of the Pacific Ocean from the Kamchatka peninsula to the southern-most tip of South America.

At 0637 UTC, Gagarin and Vostok 1 passed into orbital night northwest of the Hawaiian islands. At this time, communication between Gagarin and the ground transitioned from VFH to HF radio.

At 0651 UTC, the sun-seeking attitude control systems – critical for reentry retrofire orientation of the capsule – were activated.

Vostok 1 broke into orbital day at 0710 UTC while tracking southwest to northeast over the south Atlantic Ocean. Around this time, the automatic systems on Vostok 1 began repositioning the vehicle into the retrofire position. This reorientation was completed at 0725 UTC.

Shortly thereafter, the spacecraft’s liquid-fueled retrorockets fired for 42 seconds as the Vostok 1 passed over Angola on the west coast of Africa. At the time of retrorocket firing, Vostok 1 was 5,000 miles downrange from the landing site in eastern USSR.

Ten seconds after the completion of the retrorocket firing, commands were sent to separate the service module from the reentry capsule. The two halves of the craft, however, remained unexpectedly attached because of a bundle of wires.

The two halves of the spacecraft began reentry into Earth’s atmosphere at 0735 UTC while traveling over Egypt. Upon reentry, the reentry capsule experienced strong gyrations. At this point, the wires connecting the two crafts broke and the reentry capsule settled into its nominal reentry orientation. The gyrations were later traced to the spherical shape of the reentry capsule.

Encountering the full-force of Earth’s atmosphere a few minutes later, Gagarin experienced 8Gs during reentry.

At 0755 UTC, while still 7 kilometers above Earth’s surface, the ejection system was activated and ejected Gagarin from the reentry capsule. Gagarin’s parachutes deployed as planned and he glided to a safe landing ten minutes later.

The reentry capsule landed safely under parachute as well. Gagarin and his reentry capsule landed 16 miles southwest of Engels in the Saratov region.

The fact that Gagarin landed separately from his spacecraft was not known until ten years after the flight.

Following the flight, Yuri Gagarin became both a national and international hero. So much was his prominence and status within Soviet society, that Soviet officials banned him from flying any further space mission following the tragic loss of the Soyuz 1 mission that claimed the life of its sole crewmember.

Gagarin’s blacklisting from flight status following the loss of Soyuz 1 was done to ensure that the Soviet hero would not be lost in a spaceflight accident.

Sadly, Gagarin’s legacy would go on to far outlive him. Tragically, on March 27, 1968, nearly 7 years to day of Vostok 1’s flight, Gagarin was killed in a routine training flight of a MiG-15UTI when the plane crashed.

Gagarin’s body was cremated and his ashes buried in the walls of the Kremlin on Red Square. Prior to his death, Gagarin became the deputy training director of the Star City cosmonaut training base.

Nearly 50 years later, on April 5, 2011, just seven days shy of the 50th anniversary of Gagarin’s historic launch, the Russian Federal Space Agency successfully launched a three-person international crew of Russian and American crewmembers to the International Space Station from the same launch pad used for Gagarin’s Vostok 1 mission.

Vostok 1’s landing site is commemorated today with a 25 meter tall silver metallic rocket ascending to space on a curved column of metallic flame. The monument also includes a 3 meter tall white stone statue of Yuri Gagarin with his hand raised in greeting.

The Vostok 1 reentry capsule is currently displayed at the museum of RKK Energiya in Korolyov, which is located near Moscow.

A monument to Gagarin, in his likeness, stands on Cosmonaut Alley in Moscow.

Space Shuttle Columbia: The first flight of an unprecedented and versatile vehicle:

Perhaps one of the best coincidences in human history occurred exactly 20 years after Yuri Gagarin’s historic flight. On April 12, 1981, thousands of people crammed the shores of Central Florida to witness another historic occasion in human spaceflight: the launch of a brand new, unprecedented, and versatile space vehicle.

Originally planned to launch in March 1981, then on April 10, NASA was forced to delay the launch of its new spacecraft until the morning of April 12 to fix a problem with the craft’s 5 redundant computers.

On the morning of April 12, the countdown proceeded without pause. The two member flight crew boarded their vehicle, and the launch control team monitored the vehicle’s systems.

All systems were go for launch. The countdown resumed and counted down the final nine minutes.

At T-25secs, the most complex machine ever built – one with well over one million moving components – took control of its countdown. Then, at T-3.8secs, the vehicle’s engines roared to life.

At T+2.88 seconds, the command to ignite the vehicle’s Solid Rocket Boosters was issued, as were the commands to blow the eight SRB hold down bolts and disconnect the three T0 umbilicals attached to the vehicle.

At 07:00:03 EST, April 12, 1981, the Space Shuttle Columbia gracefully lifted off LC-39A at the Kennedy Space Center, on only its second launch attempt, to inaugurate the Space Shuttle Program.

Clearing the launch tower, Columbia executed a perfect roll/pitch/yaw maneuver to place herself on the proper alignment for a 40.3 degree 166nm orbit.

After 2mins 12secs, the SRBs separated from the External Tank and successfully parachuted into the Atlantic ocean off the coast of Daytona Beach.

After 8mins 32secs, Columbia’s three Space Shuttle Main Engines shutdown and the vehicle entered its preliminary orbit.

After two days in space, Columbia fired her OMS (Orbital Maneuvering System) engines to perform her deorbit burn.

On April 14, at 1018 PST, what would become the tell-tale sonic booms of a Shuttle landing echoed across southern California. Two minutes later, at 10:20:57 PST, Columbia slowly plopped onto runway 23 at Edwards Air Force to end the first or what is now understood to be 135 Space Shuttle missions.

For that last 30 years, the Space Shuttle Program has proven itself invaluable in mission-specific versatility, enabling us to learn an immeasurable amount about Earth, medicine, science, our solar system, our galaxy, the universe, and international cooperation.

But it is arguably the unprecedented success of STS-1, and the lessons learned from that flight, that has enabled the Shuttle Program to become what it is today.

In all, the most complex machine ever built logged only 61 In-Flight Anomalies on STS-1, an astonishingly low number considering the immensely intricate nature of the Space Shuttle vehicle. Moreover, several of the IFAs experienced during STS-1 were simply a result of seeing how certain hardware elements performed in-flight – something that could not be tested prior to STS-1.

Specifically, here, was the performance of the Development Flight Instrumentation (DFI) package on Columbia.

As noted by the post-flight IFA review for STS-1, available -for all the missions – for download on L2, “During STS-1, the DFI wideband ascent and DFI PCM recorders exhibited a dropout of approximately 400-milliseconds duration 350 milliseconds after SRB ignition.”

An analysis of post-flight data revealed that a larger than expected 15-to-18 Hz component in the vehicle’s axis contributed to a larger than expected vibration environment in Columbia’s crew cabin at launch.

“Analysis of the vehicle-induced vibration input to the recorders was performed in an attempt to find a frequency to which the recorder shock isolators could be tuned” and a “low-level sine vibration (0.25g peak-to-peak input) test was performed on the DFI PCM recorder to determine the isolator resonant frequency.”

These tests showed that the design of 45 to 50 Hz resonance was optimum. As such, it was determined that the loss of data was the result of the DFI recorders being susceptible to the frequencies experienced by the vehicle immediately following SRB ignition.

No corrective actions were planned or implemented, and the minor data hits that could result from SRB ignition were accepted for STS-2 and STS-3.

Another such IFA toward un-tested vehicle performance came during payload bay door closure on FD-3.

Classed as IFA STS-1-V-45A, the review notes that, “The Payload Bay Door (PLBD) closure overlap on rehearsal and entry days was more than predicted for STS-1. During door operations on rehearsal and entry days, the STS-1 crew reported a door centerline overlap in excess of 3 in. at the number 12 latch location.”

At the time, a 4 inch overlap was the design maximum. To gather more data on this, a theodolite measurement system was added to STS-2.

The IFA review eventually determined, following on-orbit observations from the STS-2 crew of no apparent overlap, that the “crew visual technique cannot be used to establish the precise magnitude of any overlap/gap condition, especially in the aft portion of the payload bay.”

No further action was required on this IFA, and it had no effect on subsequent missions.

Review Columbia’s history – from birth to death – via these two part specials:

Now, 30 years after STS-1, Columbia’s legacy – like that of Yuri Gagarin’s – has sadly outlived her.

The dedication and intense review of all vehicle system performance is something that has rightfully never waned within the Shuttle Program. To this day, an extensive post-flight review is conducted on each vehicle following the completion of a mission.

And plans are in place to continue that process right through a complete post-flight review for STS-135 – despite the fact that no mission will be flown after STS-135 this summer.

In short, while the Shuttle Program has proven itself many times over, it has always reinforced our desire to learn everything possible about our spaceflight vehicles and to never give up on the quest for understanding & engineering data.

Even now, as NASA prepares Columbia’s remaining sisters (Discovery, Atlantis, and Endeavour) for retirement, an extensive post-service tear-down and inspection plan has been created by NASA to study and examine parts of the vehicles that have been in service since the three remaining vehicles began flying.

(Images: MaxQ Entertainment/, NASA TV, L2 Historical).

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