1K “Buran” - the only space flown orbiter.

Airframe no.

1.01

Energia designator

1K

Alt. designators

Buran, Baykal (before early 1988)

The first flight series orbiter of the program. Flew the only orbital flight of the program. Buran was the first of these orbiters and received the designation 1K (Vehicle 1).

The orbiter initially had the name “Baykal” painted on its side, apparently by accident; the name “Buran” was still classified, so “Baykal” featured on design drawings as a placeholder. In a rush to prepare the orbiter for its maiden flight, the technicians are said to have painted on whatever was on the drawing, before a separate, final design had arrived. By April 1988 the name had been removed and the proper “Buran” decal was applied, but the name officially remained a secret. “Buran” as a description of the program was known in the West by 1983 at the latest, when it was included in that year’s National Intelligence Estimate, but as a description of the orbiter it wasn’t known until 23 October 1988. The Soviets first showed the orbiter during a Vremya program on 29 September 1988, coinciding with Discovery’s Return To Flight mission. The segment included a photo of the orbiter and Energia on the pad during the May 1988 rollout but the “Buran” decal on the side of the fuselage was obscured. On 23 October TASS released the first official photo of the shuttle, this time with the decal completely airbrushed out, and, bizarrely, that same day announced that the orbiter had been named “Buran”. ^{1 2}

Orbiter 1K atop the VM-T Atlant at Zhukovsky in 1985. Image: Aviatsionno-Kosmicheskiye Sistemy, 1997

While manufacturing actually started a bit earlier, 1983 officially marks the start of the orbiter’s life and the airframe’s 10 year “warranty period”. In August 1985 a government decree called for the maiden flight of 1K in late 1986, already three years after the target laid out in the 1976 decree. In response, in December 1985 the incomplete orbiter arrived in Baikonur atop the VM-T Atlant. 1K was missing the vertical stabilizer and Integrated Propulsion System Base Block due to the standard Atlant mass restrictions, the landing gear also wasn’t installed and only 70% of the silica thermal protection tiles were present on the orbiter.

Orbiter 1K on the VM-T Atlant, at the PKU-50 gantry at Zhukovsky (left) and in flight to Baikonur (right). Images: Aviatsionno-Kosmicheskiye Sistemy, 1997

With delays in orbiter preparations, the flight plan for the maiden mission became more and more conservative to prevent the launch date from slipping much further. The final flight plan saw a simple two orbit, uncrewed flight, during which the payload bay stayed closed. Following the Soviet tradition, the first launch was always planned to be uncrewed, despite objections by some Buran cosmonauts in the months leading up to the launch, with Igor Volk describing the autonomous system’s maturity as “near zero”. For a flight this short, deploying the radiators or exposing the star tracker or high gain antenna wasn’t necessary, so the payload bay doors would stay closed throughout the flight. The fuel cells also weren’t essential, so batteries were mounted in the payload bay instead. According to Dementiev the complete payload bay door system with its actuators was installed, but it wasn’t qualified for full operation and more tests would be needed before Flight 2. The life support system wasn’t installed to save time, in the hopes that it could be retrofitted later for crewed flights. The avionics were also described as rather basic at this stage, with Igor Volk claiming that Buran flew using just one control loop. The cabin was quite empty in general, with most of the interior panels missing, no seats and a TV camera looking out through the window directly in front of the commander’s workstation. ^{3 4}

The infamous Buran jet engines, known as the VRDU, were never fully installed on 1K. After the decision to fly the orbiter without the engines was made in 1987, the nacelles initially stayed on the vehicle and instrumentation was installed inside, but eventually they too were removed when the VRDU was abandoned altogether in early 1988, mainly to save mass. The niches in Buran’s aft fuselage were filled in with aluminum panels and covered in thermal blankets and silica tiles. Interestingly, the throttle lever to control the engines remained in place in the cabin.

Buran’s cockpit (left) and payload bay (right) as configured for the orbital flight. Images: Reusable Orbital Ship “Buran”, 1995

The payload bay stayed closed, but it wasn’t empty. It housed the 7 tonne Block for Additional Instruments (BDP), which was the flight test configuration of the 37KB series of modules for Buran. With a design closely related to 37KE A.K.A the Kvant module on Mir, a fleet of 37KB modules would fly on Buran to the Mir space station in different research configurations. In its BDP guise, the first 37KB module was essentially a very big data logger, recording about 6000 flight parameters during the orbital test flight. On Flight 1 the BDP also served as the platform for the batteries, which were attached to the front of the module.

On October 15th 1987 the orbiter’s assembly was officially completed and in early 1988 Buran was rolled out of the assembly building and placed on the test firing stand at site 254. It didn’t sport the Buran decal just yet; the fuselage was adorned with “Baykal” until April of that year. The Auxiliary Power Units, which provide the orbiter with hydraulic power, were fired up and let Buran wiggle its elevons for the first time; the orbital maneuvering engines and the smaller control and orientation thrusters were also fired. In May 1988 Buran was mated to Energia 1L and the stack was rolled out to the pad for the first time for a series of interface tests and practice runs of the pre-launch and post-landing operations.

Buran erected at pad 110/37 in May 1988 (left) and fully erected (right). Images: Mnogorazovaya kosmicheskaya sistema “Energiya-Buran”, 2004; Albert Pushkarev/TASS.

The original plan was for Buran to be rolled back from the pad and, after some tests, return for a July 1988 launch, but a design flaw in a valve in the Integrated Propulsion System was discovered during testing at NPO Energia earlier that year and it was decided to remove the orbiter from the rocket to fix the potential issue. By 29 August the modification work and additional testing was completed and Buran was mated to Energia once more. After integration, the stack was moved to the Assembly and Fueling Facility for the installation of booster separation motors and pyrotechnics on Energia, batteries aboard Buran, and for filling the orbiter’s tanks with sintin, ammonia, hydrazine, nitrogen and air.

On 10 October Energia and Buran were finally rolled out of the MZK in preparation for launch — then scheduled for October 29th. After a 3 and a half hour journey to pad 110/37 the stack was erected to the vertical position — this took another three hours. The countdown for the first attempt proceeded flawlessly until T-51s, when a faulty rubber seal prevented the azimuthal alignment plate from separating from Energia and retracting in time and the lauch was scrubbed.

Buran on pad 110/37 before the orbital flight (left) and lifting off (right). Images: buran.ru, NPO Energia.

By 12 November the seal had been redesigned and reinstalled, and a new launch date of November 15 was set. On the day of the launch the weather was very poor but the preparations went ahead; fueling began after the ice layer on the Energia was predicted not to exceed 1.7 mm after fueling, with 2 mm the acceptable limit. Buran launched at 6:00 am Moscow Time on 15 November 1988 and touched down at the landing complex 3 hours and 25 minutes later. Gudilin recalled large chunks of ice falling from the rocket and orbiter during launch and ice was determined to be the main cause of mechanical damage to the thermal protection system observed after landing.

Buran on the landing strip (left) and being wheeled into the MZK, with program managers in the foreground (right). Images: Mnogorazovaya kosmicheskaya sistema “Energiya-Buran”, 2004; Novosti Kosmonavtiki 05/2015, p.70.

After touchdown, ventilation hoses were connected to GSE fittings behind a triangular cover on the back of the orbiter to pump cold air through the airframe and prevent the structure from overheating. Residual liquid oxygen was drained from the Integrated Propulsion System tanks and the orbiter was moved to the MZK building. There, the remaining sintin and hydrazine were drained. Buran stayed in the facility until at least the end of November, when Francois Mitterrand was able to view the orbiter as part of a delegation to watch the 26 November launch of Soyuz TM-7.

François Mitterrand and the French delegation visit Buran post flight (left) and the Buran orbiter in MIK OK post-flight (right). Images: Raketno-kosmicheskaya korporatsiya Energiya 1946–1996; the author’s archives.

Then, the orbiter was transferred to the Orbiter Assembly and Test Facility for post-flight inspections. Only ~10 tiles were completely lost; the most significant damage occured where 3 adjacent ones on the underside of the left wing near the leading edge were lost, exposing the aluminum skin to hot plasma. Over a hundred tiles had cracks, chips, erosion channels and damage to the glass coating, but not much more is known about the condition of the heat shield after the flight. The second orbiter’s thermal protection was essentially the same and it proceeded with preparations for its maiden flight.

Buran and Mriya during an early test flight (left) and at the 1989 Paris Air Show (right). Images: Photo: Aviatsionno-Kosmicheskiye Sistemy, 1997 and Jaap Terweij.

After a preliminary inspection preparations began for tests of the An-225 Mriya with the Buran orbiter. On 21 May 1989 the Mriya took off with Buran on its back for the first time and made the journey from Baikonur to Kyiv. Then, the combination flew to Zhukovsky in Moscow and back to Kyiv, before travelling to Le Bourget for the 1989 Paris Air Show, arriving there on June 7th. After a week, the Mriya and Buran flew back to Baikonur, where the orbiter was demated from the plane. In 1990 reports started emerging that Buran would not fly to orbit again, even though it was still featured in flight schedules as late as 1991. In April 1991 one more demonstration flight of the Mriya and Buran took place in Baikonur, which would end up being Buran’s last flight ever, after plans to fly to the International Aerospace Convention in Huntsville, Alabama in July 1992 fell through. The orbiter was placed in the thermal protection system bay in MIK OK, where it stayed until July 1998, when it was moved to the Rocket Assembly and Test Facility to be stacked with an Energia rocket to form an exhibit.

Left: Buran stacked in MIK RN in the late 90s. Image: Anatoly Zhdanov. Right: The aftermath of the collapse via yaplakal.com.

After less than four years in MIK RN, the roof of the building collapsed in May 2002, killing eight workers and completely destroying the orbiter and most of the Energia hardware stored in the building’s high bays. In late 2006 the decision was made to clear the debris and repair the roof. By late 2009 most of the rubble was gone and rebuilding of the roof began. The Buran orbiter was cut up and sold as scrap.

Bibliography

1. “1983 National Intelligence Estimate - The Soviet Space Program Vol. 2”, CIA Directorate of Intelligence, 1983 ↩

2. “USSR Persists in Challenging American Position on Soviet-Launched U.S. Payloads”, Aviation Week & Space Technology, 24 Oct 1988 ↩

3. “The Soviet Shuttle Story”, Spaceflight, January 1990 ↩

4. “Manned Soviet Shuttle Flight Delayed Until 1992 for Systems Installation”, Aviation Week & Space Technology, 8 May 1989 ↩