Post 12: Testing Times
“Houston is go for sep, have a great flight.”
“OK, Enterprise is, ah, set. [Unintelligible]. And stand by for the bang, Gordo.”
[Unintelligible]
“Launch ready”
“Phase one, sep. Phase two, clear.”
- Transcript from Space Shuttle Enterprise Approach and Landing Test (ALT) 1, 12th August 1977.
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Despite the higher priority the Soviet leadership placed on the Baikal shuttle programme, Mishin, Semonov and others at TsKBEM still saw the L3M lunar landing mission as their most important activity. Baikal continued to drain resources throughout the late seventies, but L3M continued to move forward, albeit at a slower rate. Aside from engineering manpower, the main conflicts between the two programmes would be over the ground support equipment, and in particular the extensive modifications needed at Site 110 to supply the new hydrolox third stage for Groza, the Block-V-III. Within months of formal approval of the Baikal/Groza design in November 1977, Pad 38 was once again blocked for N-1 launches as Barmin’s bureau began the necessary modifications. Coming little more than a year after the completion of the Pad 37 updates for Blok-Sr, this meant that Baikonur would again lack a dual-launch capability with the Groza rocket until well into 1979 at the earliest. As the L3M architecture depended upon this dual launch capability, this put a serious constraint on the project planning.
This is not to say that no work had been done. Even before the approval of the Baikal programme, good progress had been made on testing the N1F-Blok Sr version of the Groza intended to carry L3M, with the first flight of the new upper stage coming in October 1975 on N1-12L. Launching from Pad 38, vehicle 12L saw the Blok-Sr replace the old Blok-G and Blok-D stages flown on previous missions. The payload was another Soyuz 7K-LOK, in this case vehicle No.4, designated Zond 11. A small crew of turtles, insects, and plants were carried within the descent module, along with an extensive photographic payload and cosmic ray detectors in the habitation module.
Consideration was given to flying one of the remaining L3 LK spacecraft to the lunar surface in a repeat of the Zond 10/Luna 23 mission, perhaps even adding a robotic arm to be deployed from the LK to scoop up some samples, and so turn the Luna 22 cover story of an automated sample return mission into a reality. However, this option was finally dismissed, as the modifications needed for both taking the samples and then transferring them to the LOK in lunar orbit proved too challenging for the time and resources available. Another uncrewed landing with the basic LK would add little scientific or engineering knowledge, while adding a risk of failure, and in any case the mission’s main objective was to test the Blok-Sr, not explore the Moon.
The N1-12L was a success, with only a single NK-33 failing on the Blok-A first stage during ascent. This was not uncommon on Groza launches, and no longer posed an existential threat to the vehicle, with the opposing engine being shut down and the flight control system continuing with a slightly longer burn time. However, it was studied with more care on this occasion as the rocket for the first time was making use of a refined version of kerosene. Called “sintin”, this gave a small but crucial performance boost to the first three stages, that together with Blok-Sr would raise Groza’s payload to LEO from 95 to 105 tonnes. In the post-launch analysis, the State Commission concluded that the failure of the Blok-A engine was unrelated to the use of sintin, and this new fuel was cleared for use on future flights.
With the first three stages successful in delivering their payload into the required parking orbit, the focus moved to the Blok-Sr. The new high energy stage performed flawlessly, demonstrating its ability to start after several days in Earth orbit to make a Trans-Lunar Injection burn, then braking Zond 11 into a low lunar orbit three days later. On an L3M mission, the Blok-Sr’s payload would be the large GB-1, or Blok-D2, space tug, so the relatively lightweight LOK posed little challenge for the twin 11D56 engines. The LOK separated from Blok-Sr and went on to spend two days photographing the lunar surface, before discarding the habitation module and firing its own engines to return to Earth, successfully delivering its crew of turtles and fruit flies back to the USSR. This marked the first successful return of a 7K spacecraft from lunar distances since Zond 8 in 1970.
The 12L mission was repeated in 1976 with N1-13L, which flew substantially the same profile. Once again, a LOK spacecraft, Zond 12, was placed into lunar orbit and successfully returned, and the Blok-Sr proved its reliability. Unfortunately, the next mission in the L3M test programme was not so lucky, as the first test article of the GB-1 tug on N1-14L failed to reach orbit when the rocket exploded at Blok-B ignition. This time it was one of the eight NK-43 engines of the Blok-B that failed, damaging the Blok-A interstage truss such that the Blok-B was unable to separate cleanly. The depleted Blok-A pulled the rest of the stack off course, resulting in a destructive spin.
Mishin and Kuznetsov now faced a difficult choice. Stung by a repeat of the sort of high-profile engine failure that had almost destroyed his career in the early 1970s, Kuznetsov recommended delaying further launches until the issue was fully understood. Many in the 14L State Commission agreed with this, but found that their time was limited. The 14L failure had come in February 1977, just five months before the planned launch of 15L and its Mars 4NM payload to the Red Planet. Missing that launch window would mean a delay of two years for Lavochkin’s “Marsokhod” rover, during which time the American’s could upstage the Soviets with a follow-up to their dramatic Viking landers. Kuznetsov and Mishin were therefore given just three months to complete their investigations and make a recommendation to the N1-15L State Commission as to whether the launch should proceed. Of course, Mishin reported in the affirmative, and the Mars 9 probe was launched in July without incident.
The 14L mission was re-flown in September 1977 on N1-16L, and succeeded in demonstrating the GB-1 upper stage in a slimmed down L3M mission profile. Two weeks after being placed in lunar orbit by the Blok-Sr upper stage, the GB-1 tug’s 11D71 kerolox engines were fired in a simulated lunar descent manoeuvre. As planned, the stage crashed into the surface of the Moon, having demonstrated its role in carrying a GB-2 lander to a point over its landing zone. Officially, the Soviets claimed this was an impactor probe intended to support studies of the composition of the Moon, but Western observers were almost universal in dismissing this flimsy cover story and correctly deducing GB-1’s true purpose as part of a crewed landing system. (The fact that the GB-1 had been called “Zond 13” by the Soviets led some of a superstitious inclination to believe that the impact on the surface may have been unintentional, leading to a brief revival of the old “Phantom Moonwalker” myth.)
The launch of Zarya 2 in December 1977 rounded off Groza’s busiest year to date, with four launches of the giant rocket. As Pad 37 was stood down for Baikal related upgrades, the next two years would see a more relaxed cadence, with just one Groza launch per year, both of which were in support of L3M.
In June 1978, N1-18L carried the first prototype of Semenov’s GB-2 LEK lander on an uncrewed test flight. GB-2 Vehicle No.1 lacked many of the subsystems that would be needed on a real mission - in particular life support - but was able to validate the operation of Glushko’s Propulsion Unit in lunar orbit. The “Zond 14” spacecraft was unable to land without its GB-1 tug, but did perform a number of basic manoeuvres in lunar orbit before making a Trans-Earth Injection burn to send the spacecraft home. The complicated separation of the Return Capsule from the Cocooned Habitation Module was accomplished without problem, and the Return Capsule made a successful (if hard) landing in the Kazakh steppe with its crew of dazed turtles and fruit flies.
Testing of the GB-1 continued in 1979 with the launch of “Zond 15” on Groza N1-19L. The mission profile was initially similar to that of Zond 13, but this time the tug was not crashed into the Moon, but rather performed a number of additional manoeuvres in space before being left in a high lunar orbit. At the time there was speculation that there had been some failure that prevented the completion of the mission profile, as by now Western analysts had a pretty clear idea of the likely L3M mission profile, including the role of the GB-1 as a crasher stage. Later events would show this assumption to be incorrect.
1980 opened with the launch in February of the second GB-2 LEK vehicle, inevitably labelled as “Zond 16”, on N1-20L. This was a repeat of the Zond 14 mission of two years previously, but with a much more representative vehicle. Zond 16 was effectively a fully functional LEK lander, containing all the systems needed to support the planned lunar expedition. Once delivered to lunar orbit by the Blok-Sr, Zond 16 separated and immediately began a series of manoeuvres to bring it to a rendezvous with the Zond 15 GB-1 stage. Using a modification of the Kontakt system originally developed for L3, over the course of a day Zond 16 brought itself to within a hundred metres of Zond 15. An actual landing attempt was not possible, as Zond 15’s liquid oxygen supplies had been depleted over the previous year, but by using the GB-1 stage as a target the Soviets were able to test out one of the riskiest aspects of their chosen mission profile. An automatic docking should have been possible, but Mishin’s engineers decided the risk of damaging the two spacecraft was not worth the marginal benefit of demonstrating a docking. They also had other plans for the GB-1 stage that docking with the single-use Kontakt probe-and-target system would preclude. A day after the rendezvous, Zond 16 backed away from the GB-1 and performed an orbit-raising burn equivalent in duration to that needed for a final landing. It spent two more weeks in lunar orbit before performing Trans Earth Injection and making a safe return to Earth.
October 1980 saw the most dramatic L3M mission to date, and marked the point at which the Soviets finally admitted in public that they had a crewed lunar programme in development. On 21st October three cosmonauts - Valeri Bykovsky, Oleg Makarov and Gennadi Strekalov - boarded GB-2 LEK vehicle no.3 and lifted off from Site 110 Pad 37 aboard Groza vehicle 21L for a test of their spacecraft in Earth orbit. This marked the first crewed launch of the Groza, as well as the first piloted L3M mission, and so a “Zond” or “Kosmos” designation was out of the question. The mission was instead announced as “Zvezda 1”.
Nerves were high for this first crewed launch, but although the Groza rocket itself had a less than perfect record, the N-1’s SAS escape system had proven itself on each of the 3L, 5L and 6L failures (the 14L mission hadn’t carried an SAS), pulling its uncrewed L1 capsule to safety every time. The escape tower was connected directly to the LEK Return Capsule containing the three cosmonauts, but in the event it was not needed, as the tower was jettisoned shortly after Blok-B staging as normal. N1-21L went on to deliver the Blok-Sr/GB-2 stack into a low parking orbit with no significant anomalies. The Zvezda 1 crew were able to unstrap from their couches and opened the interior hatch between the Return Capsule and the Cocooned Habitation Capsule, removing the Sokol pressure suits they had worn for launch and changing into more comfortable coveralls.
After a day becoming accustomed to their new accommodations, the Blok-Sr’s 11D56 engines were fired to put the spacecraft into an elliptical orbit with an apogee of 900km, just inside of the inner Van Allen belts. They remained in this orbit for almost three days before again using the Blok-Sr stage to lower them to a 270km circular orbit, thus simulating a lunar transfer and braking manoeuvre. The LEK then separated from the Blok-Sr and several days in free flight, making some minor orbit changes with the GB-2’s own engines. This phase of the mission included a spacewalk by mission commander Valeri Bykovsky, who spent almost two hours outside in his Krechet moonsuit. Makarov also donned a Krechet, but remained inside the depressurised Habitation Module as a back-up, while Strekalov sheltered in the Return Capsule in his Sokol suit. Both Bykovsky and Makarov reported difficulties in moving around the interior of the BO in the bulky moonsuits, no significant issues were found, and another milestone to a Soviet lunar landing was successfully passed.
Zvezda 1 returned to Earth after a total mission time of 9 days, 5 hours and 17 minutes. The mission had been an almost complete success, proving that the new spacecraft could support three crew members for the minimum required mission duration. There was some pressure from the leadership to move directly to a lunar landing attempt, but aside from a native engineering caution, this was ruled out in the near term by the ongoing unavailability of Pad 38 and the necessary dual launch capability. The next mission was therefore an extension - though still a bold one - of the previous flight, and finally achieving the dream that Semenov had seen denied with the L1/Zond programme: Zvezda 2 would send a LEK and its crew all the way to lunar orbit.
