Sunday is here and I've managed to find a computer
Last time we left the Soviets preparing to launch their R-6 missile for the first time, so now let's pick up the story in....
Part I Post #4: We Have Liftoff!
In June 1958 the Kazakh steppe would finally reverberate with the sound of an R-6 launch. The 25 metre missile, affectionately called “Shesterka” (“Ol’ Number Six”), had been rolled out of the Assembly and Testing Building (MIK) of the Scientific-Research and Test Firing Range No. 5 (NIIP-5) at Tyuratam on its specialised railway car and moved the two kilometres to Launch Complex 1. Here the rocket was slowly elevated to a vertical position above the flame trench and brought to rest on four short support pillars. After the base of the rocket had been clamped into place the transport car was withdrawn.
The next day, 5th June, was spent going through a battery of electrical and mechanical checks to ensure that everything was as it should be, both within the rocket itself and the instrumented payload that would verify the missile’s range and accuracy on this suborbital test. Numerous minor issues were discovered and corrected on the pad, but nothing that would call off the launch. Finally, with great care, the toxic AK271/UDMH propellants were loaded into their tanks. This task completed, the launch crew technicians retreated from the pad to their firing bunkers. Range tracking stations were checked and reported ready. Twenty minutes before planned liftoff, the gyroscopes of the guidance system were spun up and the service towers were pulled back. All systems were go. In the fire control room, the Chief Designers Sinilshchikov, Barmin and Glushko watched with varying degrees of nervousness as the second hand of the launch clock swept towards the appointed hour. With them for this inaugural launch were a host of military and Party observers, including the Deputy Minister for Defence, Chief Marshal Mitrofan Nedelin. He would report directly to Ustinov on the results of the day’s test.
At the appointed time, the commands were given: “Broach! Key to ignition! Purge! Key to vent! Launch!” and the four twin-chambered RD-215 engines at the base of the Blok-A booster roared into life. The thrust of each engine steadily increased, measured and relayed to the firing room by instrumentation in the hold-down clamps and on-board the rocket itself. Once full thrust was achieved in all engines, the clamps were released and the 340 tonnes of Shesterka began to slowly rise from the earth. As the R-6 cleared the lightning towers there were loud shouts and cheers from many of the observers in launch control. Success! Congratulations comrades, all your hard work has paid off! Those specialists with more experience in test launches held their tongues. This was the most complex rocket they had ever attempted to launch, and the seasoned experts were all too aware that the dangers were not over yet.
For the first two minutes everything appeared nominal, with the R-6 correctly following its programmed trajectory. As reports started coming in from the first of the tracking stations it seemed the missile was well on course for its target zone on the Kamchatka Peninsula. With just seconds to go before first stage separation, everything looked good.
The first indication of a serious problem was a sudden reduction in thrust from Engine 3. In a matter of seconds, all thrust from that engine disappeared. With the three remaining engines still at full power, the rocket stack immediately started to yaw alarmingly. The on-board guidance system recognised the deviation and attempted to compensate, but the four small vernier steering rockets were unequal to the task. By the time the three remaining engines shut down together as planned, the R-6 had already entered a fatal tumble. As the explosive bolts fired to split the two stages, the angular momentum transferred to the Blok-B left it in a violent supersonic spin. Blok-B’s propellant tanks ruptured, spilling 60 tonnes of UDMH and nitric acid into the void, as aerodynamic forces finished the job of ripping the R-6 to pieces. In the midst of the destruction some of the hypergolic propellants combined and ignited, creating a bright fireball. The remaining unburnt propellant was transformed into a haze of toxic rain, which descended onto the steppe below as the more massive fragments of rocket body continued on a ballistic trajectory that would end in the wastelands of Siberia, thousands of kilometres short of the intended target.
In the immediate aftermath of the R-6 failure, Sinilshchikov jumped to the seemingly obvious conclusion that the fault must lay in Glushko’s RD-215 engines. Glushko was infuriated by this accusation. His factory had produced dozens of RD-215s and hundreds of similar rockets. All had undergone rigorous testing before being shipped to Tyuratam for integration. Those engines had been in perfect condition when he’d handed them over! The fact that Sinilshchikov blamed the RD-215 in front of Marshal Nedelin, before a technical investigation had even started, poisoned relations between the two Chief Designers from that point on.
Over the following days and weeks it slowly became apparent that Glushko had been correct. The RD-215’s had been in perfect condition when they were received, but following their installation on the Shesterka OKB-1 technicians had conducted a fuel loading test. This type of test, which had been performed many times before on other rockets, involved filling and pressurising the tanks, checking for leaks, then emptying the rocket again. To avoid the risks associated with using the toxic propellants, the test instead filled the tanks with water laced with an additive liquid similar to cleaning fluid which brought the mixture to the same density as the propellants. This liquid was used and re-used for multiple tests, and it soon became apparent that at some point the batch had become contaminated. When the test fluid storage tanks were inspected a waxy residue was discovered on the inner walls. Some of this residue must have remained in the R-6’s propellant tanks after the test, and after launch a small plug of matter had been dislodged and blocked a feed line to the failed engine, cutting off the propellant supply.
Glushko seized on these results as a complete vindication of his OKB-456. In a meeting of the Rocket Propulsion Coordination Committee (KKRD, the main forum for discussions between the various institutes involved in missile development), Glushko personally attacked Sinilshchikov as not competent to be the Chief Designer of the lead institution for ICBM development. Whilst Yangel tried to act as a peacemaker between the two rivals, Chelomei actively supported Glushko. The meeting broke up in acrimony, with the only conclusion recorded being that the test procedures would be updated, filters installed in the propellant tanks, and a second R-6 launch attempted within two weeks. As events turned out, that would be too late.
Unaware of the Soviets’ attempted launch, the engineers of the Naval Research Laboratory were at that moment preparing for their own mission. Following their April launch attempt, which had just barely missed reaching orbit, the Navy team had gone through a detailed analysis of their design to ensure that the next attempt would succeed. The review quickly identified the cause of the April stage three separation failure and implemented a fix to avoid a recurrence, but it also threw light onto several other potential issues that had been previously missed. After eight weeks of analysis, modifications and testing, there was a feeling of confidence as final preparations began.
Assembly of the Vanguard stack was completed on Monday 16th June 1958 with the installation of the solid rocket 3rd Stage. Unlike the Soviet R-6, Vanguard was assembled directly on the pad, with the payload left off whilst the stack underwent final checks. Throughout Tuesday 17th checks were performed on the vehicle propulsion system pressures, the pipelines supplying water to the launch stand, and the fire-fighting facilities. Also undergoing checks was the satellite that, it was hoped, would open the Space Age. At 1.47 kg, the grapefruit-sized metal ball could easily be held by one man, as long as he took care to avoid damaging the radio antennas and solar cells that studded the tiny spacecraft. With everything checking out green, the payload was declared ready.
As Tuesday turned into Wednesday, prospects looked good. The previous Sunday had been the hottest of the year, with temperatures topping 35 degrees Celsius, and the weather forecast for the 18th remained fine and clear, with wind speeds averaging around 15 km/h and gusts not exceeding 35 km/h: perfect conditions for a launch.
The day’s preparations started at 1am, as pad technicians began propellant loading the Vanguard 1st and 2nd stages. The 1st stage was fuelled with relatively conventional kerosene, but the 2nd stage used 1 470 kg of Nitric Acid and UDMH, necessitating extreme caution. The smallest leak of these highly toxic, highly corrosive chemicals would necessitate an evacuation of the pad whilst specialists in chemical protection suits were brought in to make the area safe. Fortunately, no such leak occurred this time, and by 11am the go-ahead was given to install the satellite payload on the nose of the fully fuelled rocket.
At 14:00 the countdown clock was started. 45 minutes later, the satellite was switched on and checked: all systems green. At 17:25 cryogenic liquid oxygen began filling the first stage oxidiser tanks: the rocket was now fully loaded with propellant. An hour before scheduled lift-off, the service crane was retracted and Vanguard stood alone and proud on its pad in the late afternoon sunshine. The countdown was proceeding precisely on schedule. With just minutes left on the clock, the rocket’s telemetry, beacon and command receivers were switched to internal power, then the last air conditioning umbilicals were retracted and the oxygen vents closed. All tracking stations were standing by. The weather was fine.
Finally, at 19:00 exactly, the firing switch closed and the 1st stage X-405 engine ignited. Six seconds after ignition, from out of a chaos of light and smoke, Vanguard left the launch pad and began its climb into space. From inside launch control, from the tops of buildings and parking lots all round the Cape, and from vantage points for miles up and down the Floridian coast, people looked up to follow the fiery trail of the American rocket as it arced into the unknown.
Just over two minutes after its dramatic departure, the observers saw the distant light dim and fade, only to quickly re-appear as the first stage was discarded and the second stage took up the load. Before another two minutes had elapsed the second stage too expired, it’s job done. Tracking stations reported Vanguard was dead on course; telemetry indicated the separation was clean. Seconds later the solid 3rd stage ignited, banishing the ghosts of April’s launch failure. Controllers at Cape Canaveral nevertheless bit their nails and held their breaths as the burn continued. So close! Don’t let it fail now, please! So damned
close! The thirty-second burn seemed to stretch into hours, but finally the thrust tailed off and the stage fell dormant. In Launch Control there was silence. Finally, it was one of the Tracking Stations which broke the spell: “Tracking confirmed, Vanguard is in orbit. I say again, Vanguard is in orbit.”
With that announcement Launch Control erupted with cheers and applause, as loudspeakers began to relay the distinctive “Beep-beep-beep!” signal from Vanguard that would soon be famous all over the world. That sound marked June 18th, 1958 as the dawn of the Space Age.