Today, Roscosmos is celebrating the 60th anniversary of the Vostok-1 mission, which launched Yuri Gagarin and the first human spaceflight, while NASA simultaneously commemorates the 40th anniversary of the first launch of the world’s first reusable spacecraft, when John Young and Bob Crippen embarked on the most ambitious test flight in history aboard the shuttle Columbia.
The anniversaries arrive at a crucial turning point in space exploration, as more and more emphasis shifts to the commercial development of the space industry as well as the establishment of multiple, sustainable destinations both in and beyond Earth orbit.
On April 12, 1961, Cosmonaut Yuri Gagarin made history when he became the first human in space. His launch aboard a Vostok-K rocket, a variant of the R-7 Semyorka, on the Vostok-1 mission took place from Site 1/5 at the Baikonur Cosmodrome in what was then the Kazakh Soviet Socialist Republic.
Site 1/5 was the same complex that launched Sputnik on October 3, 1957, and after the Vostok-1 mission, the site gained the nickname “Gagarin’s start” in honor of Yuri. The complex continued to launch crews to space until Soyuz MS-15 on April 17, 2020.
Managed by Sergei Korolev, the Vostok program began with the launch of a non-recoverable spacecraft, Vostok 1KP, named Korabl-Sputnik on May 15, 1960. Its objective was to study the operation of life support systems and the stresses of flight. It contained scientific instruments, a television system, and a self-sustaining biological cabin with a mannequin.
The spacecraft radioed both extensive telemetry and pre-recorded voice communication. Although it was not designed to recover from orbit, the retro rockets, which caused the spacecraft to deorbit, fired incorrectly and the spacecraft did not reenter the atmosphere as planned.
After the partial success of Korabl-Sputnik-1, Korolev’s team turned to the next iteration of Vostok spacecraft, named Vostok 1K. Designed to be fully recoverable from orbit, its objective was to test the descent from orbit to develop the recovery systems.
Also equipped with a life support system, it launched on August 19, 1960, carrying two dogs, named Chaika and Lisichka, who unfortunately met their demise early in the flight as the rocket exploded mid-flight. The failure was attributed to the disintegration of the combustion chamber of the RD-107 engine on the Blok-G booster due to high-frequency pressure oscillation.
This phenomenon had been observed before and necessary measures had already been taken to resolve the issue, but the rocket used for the launch had older engines, which lacked corrective measures.
This was the first major setback for the Vostok program, and hence this mission was not named. This accident also expedited the work on the Emergency Escape System, which would pull the crewed capsule away from the failing rocket to prevent the Loss of Crew.
Korolev’s team was determined for a much-needed success, and despite a severe heatwave in Kazakhstan, the launch campaign resumed with the next mission, named Korabl-Sputnik 2, which launched on August 19, 1960. The spacecraft was identical to its lost predecessor in configuration and payload and carried two dogs, Belka and Strelka, as well as a multitude of biological and botanical objects, including a pair of white rats, 40 white and black mice, insects, various plants, fungi, several kinds of cereals including corn seeds, alongside the payloads for microbiological, genetic, immunology, and other life-science experiments.
The container was also integrated with an ejection seat, fitted inside Vostok’s descent module.
Launched from Baikonur, the mission was a huge success for the Vostok space program and proved the Soviet’s advancement in space. Belka and Strelka became the first living beings to be recovered from orbit. The spacecraft was only the second object to be recovered from orbit, with the first being the American Discoverer 13 mission.
The success of Korabl-Sputnik 2 gave a much-needed boost of confidence to the teams. According to a document detailing the plan for human spaceflight under the Vostok Program, the decision was made for one or two more Vostok 1K flights, followed by two uncrewed flights of the next major iteration of the Vostok spacecraft, named Vostok 3KA, followed with a crewed flight by December 1960. The document, dated September 10, 1960, was signed by top leaders in the Soviet defense industry, including Deputy Chairman Dmitriy Ustinov and approved by CCCP’s Premier Nikita Khrushchev, which indicated its elevated importance.
However, on October 24, a major setback occurred at the Baikonur Cosmodrome when an intercontinental ballistic missile exploded during testing, killing over 100 people. Named after the death of a Chief Marshal of Artillery, Mitrofan Ivanovich Nedelin, the Nedelin catastrophe was one of the worst disasters in the history of spaceflight. The extensive damage at Baikonur meant that it would be two weeks before work on the Vostok program continued. It was soon realized that the original target for a December crewed launch was unrealistic.
Following repairs, and to prove their triumphant feat in August 1960 was not a lucky fluke, the Vostok 1K spacecraft was launched for the third time from Baikonur on December 1, 1960. The launch was successful, carrying a variety of biological specimens, including two dogs, Pchelka and Mushka, to an orbit of 187 x 265 kilometers.
However, while ground controllers reported smooth operations of all systems aboard the spacecraft, an anomaly was noticed by the telemetry officers when the ground controllers sent commands for the spacecraft to return to Earth. They noticed that despite the activation of the braking engines, which were required to fire to begin reentry, the separation of the Descent Module and the Instrument module did not take place. Next, they registered the activation of the APO self-destruct mechanism, followed by the disappearance of radio signals from the spacecraft.
Further analysis into the anomaly revealed a problem with the onboard flight control systems where the attitude control thrusters failed to place the vehicle in the correct orientation against the direction of the flight for the braking maneuver. As a result, the braking engine failed to deliver the required thrust for the planned reentry, leaving the spacecraft on a shallow descent trajectory with an unpredictable landing point. This activated the self-destruct mechanism to prevent access to classified technology beyond Soviet territory.
Despite the failure of Korabl-Sputnik 3, the Vostok program continued at an incredible pace, even if not as fast as it had been projected in government documents in November 1960.
On December 22, the Vostok 1K spacecraft lifted off for the last time, carrying two dogs, named Kometa and Shutka. The telemetry on the ground confirmed nominal first stage performance and separation, planned at T+ 119 seconds, followed by the jettisoning of the payload fairing. As the core stage (also referred to as the second stage) of the rocket continued firing, the radio-control system issued a command at T+ 304 seconds to pressurize the propulsion system of the third stage to get it ready for scheduled ignition in flight.
However, according to the telemetry received on the ground, the command was not issued. This, although significant, didn’t pose a threat to the main objective of getting to orbit. At T+ 321 seconds, the radio control system recorded the command for the ignition of the third stage engine. The engine fired normally until T+432 seconds into the fight when telemetry indicated a premature engine cutoff.
According to the flight program, the third stage had to operate until T+ 676 seconds in the flight, but a premature cut-off meant that the spacecraft was short of the required orbital velocity. Vostok 1A’s final flight’s main objectives failed as it was unable to make it to orbit and was doomed to an immediate plunge back into the atmosphere.
The emergency escape system was activated, however, and worked as expected. The spacecraft landed 3,500 kilometers downrange of the launch site at a location where the rescue operation took days and temperatures reached-40°C. After a few days, both dogs were recovered alive, and the spacecraft was returned to Moscow.
The failure was attributed to the gas generators of the third stage, which disintegrated 425 seconds into flight. Despite the botched launch, the mission provided invaluable lessons to the engineers and proved that its parachute system could provide a safe landing, even though a considerable effort was still required to develop the ejection seat system for the cosmonauts.
During the flight tests of the Vostok 1K prototypes, Korolev requested his engineers provide a series of upgrades for the Vostok spacecraft, capable of carrying pilots onboard. Named Vostok 3KA, it was the next major iteration for the Vostok spacecraft.
Two uncrewed Vostok 3KA flights were scheduled, and the approval for a crewed mission was contingent upon the success of these two. Unlike the previous Vostok 1K flights, these missions were planned to last only a single orbit to imitate the plan for the first human flight.
Even though the recent failures of Vostok 1K were not encouraging, it was decided to go ahead with the first launch of Vostok 3KA. Named Korabl-Sputnik 4, the launch occurred successfully on March 9, 1961. It carried the dog Chernushka, a mannequin named Ivan Ivanovich wearing a functional SK-1 spacesuit, and biological specimens including mice, guinea pigs, frogs, flies, microbes, plant seeds, and human blood samples to continue research on the effects of radiation and weightlessness on biological objects.
After one orbit, the descent module successfully re-entered the atmosphere by parachute. The dog was recovered alive and the mission was a success.
Korolev sent an official request for authorization to launch the second Vostok 3KA spacecraft. The second launch was intended to re-confirm for a second and final time that the new spacecraft, its rocket, and support elements were fully ready to safely complete all phases of a one-orbit piloted mission.
Like the previous flight, it lasted one orbit and carried a dog named Zvezdochka as well as a mannequin. For this flight, the launch facility received a new mobile gantry with an elevator leading to the top of the rocket. The future spacecraft pilot would need to take just a few steps from the base of the rail platform, from where an elevator cabin would slide up along the metal gantry right to the hatch of the spacecraft.
This mission was also a complete success, paving the way for getting approval for a crewed mission.
The culmination of years of hard work of engineers towards the Vostok program led to the momentous day of April 12, 1961, when cosmonaut Yuri Gagarin became the first human to venture into space. The Vostok 1 mission entered a 169 by 327 kilometer orbit inclined 64.95 degrees.
Gagarin completed a single orbit before returning to Earth. Soviet engineers had not yet managed to slow the spacecraft sufficiently for touchdown, so Gagarin ejected from the capsule during the final descent and landed safely under his own parachute.
The Vostok 3KA spacecraft worked flawlessly, and would carry five more cosmonauts to space, including Valentina Tereshkova, who became the first woman to go to space on June 16, 1963.
From Vostok to STS-1
Twenty years to the day after the historic Vostok 1 mission, STS-1 commander John Young and pilot Robert Crippen launched onboard Space Shuttle Columbia from LC-39A at NASA’s Kennedy Space Center, beginning the first flight of the Space Shuttle program.
Multiple milestones were completed prior to launch, including Columbia’s arrival at KSC on March 24, 1979 onboard a Shuttle Carrier Aircraft. During the flight to KSC, Columbia lost many thermal protection tiles, showing a need to re-evaluate the bonding mechanism used to adhere the tiles to Columbia’s airframe.
After more than a year and a half in Orbiter Processing Facility-1 (OPF-1), Columbia was moved to the Vehicle Assembly Building on November 24, 1980.
After more than a year at KSC, Columbia, mated to her external tank (ET) and two solid rocket boosters (SRBs), was rolled out to LC-39A on December 29, 1980. Columbia fired all three of her SSMEs for a Flight Readiness Firing (FRF) on February 20, 1981.
The original launch on April 10th was scrubbed due to a timing problem in one of Columbia’s general-purpose computers. A patch was installed, and launch was reset for April 12th.
On the pad that morning, Young and Crippen prepared for something no other human had attempted before. Whereas Gagarin 20 years earlier had the knowledge of two successful uncrewed test flights of the Vostok system, Young and Crippen had no such knowledge to fall back on.
The Shuttle system had never flown before. The SRBs had been fired on the ground, but not in flight. Two SRBs had never been fired at the same time. The SSMEs (Space Shuttle Main Engines) and SRBs had never worked together at that point.
This was the test flight. And it stands to this day as the most ambitious test flight in history. There was no room for error. All Young and Crippen had in case of an emergency were a couple of “feel-good” ejection seats — the successful use of which in flight below 40,000 feet was dubious at best given the SRB plume.
As a result, when the twin SRBs lit at T+3 seconds, an overpressure wave caused damage to 148 tiles of Columbia’s thermal protection system and significantly damaged the structure and hydraulic lines the orbiter’s body flap.
This issue was corrected on subsequent missions with the additional of increased sound suppression from the pad and in the SRB mounting cutouts in the Mobile Launch Platform.
Once on orbit, Young and Crippen discovered missing tiles on the OMS pods; as Columbia did not carry a Canadarm on her first mission, there was no way to inspect the ship for other missing or damaged thermal protection system areas. As such, reentry was performed without firm knowledge of the state of Columbia’s heat shield — though an imaging attempt over Hawai’i during the flight was attempted.
After 36 orbits, Columbia performed the deorbit burn, with Young and Crippen confirming the burn afterward to Mission Control when they came back within ground station communication coverage over Australia.
Columbia reentered without contact with Mission Control, with Vandenberg’s tracking station going down just before anticipated Acquisition of Signal from the ship. Vandenberg was able to restore their radar tracking in time to lock on to Columbia as she came over the horizon — right on ground track and energy as she headed to Edwards.
Easing down on the lakebed Runway 23, Columbia successfully competed the first flight of reusable spacecraft and heralded a shift in human space exploration that created a model for astronomical, commercial, and international uses of and cooperation in low Earth orbit.
Vostok and STS’s Legacy
Standing on the shoulders of giants, SpaceX’s Starship development and test program at Boca Chica, Texas has adopted the iterative development methodology, which is a reflection of steps taken by Sergei Korolev and his team to launch humans to space for the first time.
Ever since the Starhopper test article was completed on December 23, 2018, the company’s production of Starship prototypes and test cadence has increased exponentially. Starship’s most recent milestone was marked by the first high-altitude flight of a full scale Starship prototype, first achieved with SN8 on December 9, 2020. Since then, SpaceX has assembled and launched 3 additional prototypes, SN9, SN10, and SN11, although none have yet survived the landing.
SpaceX is now working on Starship SN15, which rolled out to the launch site on Thursday, April 8. According to Elon Musk, SN15 sports hundreds of modifications in structure, avionics, and engine, which SpaceX hopes will result in a successful flight and landing.
The most recent official plans from SpaceX do not include a launch abort system for Starship. There is historical precedent for this, rooted in none other than the Space Shuttle program. The daring STS-1 test flight featured only ejection seats for Columbia’s two pilots, and the effectiveness of those seats in a real emergency was questionable. The seats were removed after the completion of the test flight series.
The one and only Space Shuttle launch failure, the Challenger disaster on STS-51-L, can be traced not to a fundamental design issue, but an operational failure to adhere to launch weather criteria. The lack of an abort system on STS was compensated for with extensive ground testing and design redundancy. The same will be true of Starship, with possibly hundreds of uncrewed test flights prior to launching crew.
The Space Shuttle program ended in 2011 with the launch of Atlantis on STS-135. While not all of the goals of the Shuttle program could be met, Starship has the potential to be a truly reusable, super heavy lift class vehicle, which can support missions in both Earth orbit and deep space.
Meanwhile, NASA’s shuttle-derived Space Launch System (SLS) rocket has been under development and testing since 2011. Two test flights have occurred to test the Orion spacecraft and the launch abort system. This includes Exploration Flight Test-1 in 2014 and Ascent Abort-2 in 2019.
Following precedent set all the way back in the Vostok program, SLS and Orion will complete an uncrewed test flight, Artemis I, prior to launching crew. This practice has also held true for a new generation of ISS crew transport vehicles, with both SpaceX’s Crew Dragon and Boeing’s Starliner vehicles flying uncrewed test flights.
SLS also leverages flight heritage hardware from STS, using the same main engines and solid rocket boosters. The Space Shuttle Main Engine, or SSME, is now known as the RS-25. 14 RS-25s with Space Shuttle heritage have been modified for use on the first four launches of the SLS for the Artemis program, along with two other RS-25s which have no prior flight history.
The four veteran RS-25s that are going to be flown on Artemis 1 are E2060, E2058, E2045, and E2056. All of these engines, currently attached to Core Stage-1, fired for eight minutes on March 18, as part of the second attempt of the Green Run hot fire test on the B-2 test stand at NASA’s Stennis Space Center. This test is not dissimilar to the Shuttle program’s flight readiness firings, nor SpaceX’s pre-flight static fire tests.
The lessons and practices from historical, groundbreaking missions continue to echo in today’s space programs, from abort systems to test flight planning. As a result, a new line of low Earth orbit and deep space vehicles will be safer and more capable, enabling a new era of sustained human presence beyond Earth.
(Lead photos via NASA)