Buran-Energia : The Soviet Space Shuttle 2.0 on a Moon Rocket

paulshillito Rockets, space 0 Comments

To many the Soviet Space shuttle or Buran was just a copy of the NASA one, it looks surprisingly similar and was meant to do similar things but beyond the looks the two are really quite different, not only in the shuttle vehicles themselves but also the way it got into space, in many ways the Buran could be seen as the Space Shuttle 2.0.

To build big things in space, you have to have an affordable way to get off the ground. As spectacular as the Apollo era rockets were on-camera, they were hardly efficient: the Titan IIIC cost around $4,500 in 1972’s currency to deliver each Kg of hardware to Low Earth Orbit. The Saturn 1B could lift a larger payload, but cost around $6,800 per kg. Adjusted for inflation, that’s about $40,000 per kg in today’s money or $40 million per ton.

NASA aimed to solve this problem with a ‘space truck’: the ‘STS’ or the ‘Space Transportation System’, that eventually became known as the Space Shuttle. Originally the Shuttle was designed to fly up to sixty missions per year to Low Earth Orbit, at a cost of just $453 per kg, less than a tenth of the cost of rocket launches at the time. This would enable NASA to construct space stations, or large modular spacecraft for manned missions to other planets. More worryingly for the Soviets, they believed it would have a greater military role like capturing and returning satellites from orbit and deploying space weapons.

When the STS was announced in 1972, Soviet rocket engineers were hardly concerned with efficiencies. They were still working on Sergei Korolev’s giant ‘N1’ rocket. Korolev had died six years earlier and his deputy Vasily Mishin had taken his place. The ‘N1’ still carried the Soviet dream to land Cosmonauts on the Moon. But after four failures in four test launches, the ‘N-1’ program was suspended in 1974. The Soviet leadership replaced the now disgraced Chief designer Vasily Mishin with the rocket engineer Valentin Glushko, who went to work on an alternative program of lunar missions using the smaller ‘Proton’ rocket.

However, in early 1976, Glushko received instructions to develop a ‘symmetrical response’ to the American Shuttle. Over 600 Soviet institutions were enlisted to work on the huge project. The new spacecraft would be called ‘Buran’, which translates to English as ‘Snowstorm’, or ‘Blizzard’. On the outside, ‘Buran’ looked like a copy of NASA’s Shuttle which wasn’t surprising as much of the non-confidential plans had been on public view for years. This allowed the Soviets to adapt a proven airframe which saved the engineers precious time and allowing them to improve on the American design. ‘Buran’ would allow the Soviets to leapfrog to ‘Shuttle 2.0’, with greater payload capacity, mission flexibility, and better crew safety.

The major difference between the US Space Shuttle and the Buran is that the Buran was unpowered, it did not have the main engines attached to it like the US Shuttle. Instead, it would be attached to a giant heavy-lift rocket called the Energia. Doing this meant that the Buran had not only a larger payload 30 tons to the US shuttles 24 but also it could be turned around much more quickly. It also did away for the need of the solid rocket boosters that the US shuttle had used. These were a part low-cost fix to get extra thrust and a political move to keep ballistic missile makers in the space program. Powerful as the thrusters were, they were not controllable once ignited and due to a subzero temperature launch, the O rings of one booster failed, which led the loss of the Space Shuttle Challenger.

One of the biggest problems slowing down the US shuttle launches was that the main engines had to be removed and refurbished after each mission, this was a major job which took months to complete.

The Buran, on the other hand, had just thrusters used for manoeuvring in orbit that were rated for 66 flights without replacement.
It was also going to use two turbojet engines, the same ones that were used in the Sukoi 27 fighter. The original idea was that these would give a much greater range if couldn’t land at the designated airbase or it could make several attempts at a landing if it detected a problem. It could also take off and fly around like a normal plane from any airbase. Originally, these turbojets were to be placed at the base of the tailfin. It was then realised that two were not enough so two more were added below the first two. But difficulties in protecting them from the heat of re-entry, along with the extra fuel, equipment and weight they added, caused delays and cost overruns which meant they were not ready for the first flight and the Buran had to operate in glider mode without them.

The US shuttle, on the other hand, could not use its main engines so it was always going to be an unpowered glider on landing and therefore could have only one chance to get it right.
The Buran was also designed from the outset to be flown completely automatically without any crew if required. If the crew were onboard, the pilot and the co-pilot had ejection seats something that had been ditched on the US shuttle.

But if ‘Buran’ was to be the headline, Glushko was interested in the fine print: he was determined to keep a Soviet route open to the Moon. With this in mind, he tasked his design bureau with building an independent rocket to launch ‘Buran’ as a payload, this way the Soviet shuttle would be much closer the design goals of the original American STS shuttle.
This new rocket, called ‘Energia’, weighed almost as much as the scrapped ‘N1’ at 2500 tons on the launchpad, to the N1’s 2750 tons. ‘Energia’ had enough power to either launch ‘Buran’ to orbit with a 30 ton payload, or launch up to 100 tons without the orbiter: even more than the N1’s planned 95 tons.

‘Energia’ achieved its incredible power using staging: four booster segments separated from the central core during launch with each booster carrying an RD-170, the most powerful rocket engine in the world.

Now many will say that Saturn V F1 engines made by Rocketdyne were the most powerful, well they were the most powerful single chamber engines but the RD-170 was still a single engine but it used 4 chambers instead of one to get around the issue of combustion instability, a problem that gets worse as the chamber size increases and can literally blow the engine apart. The Americans used baffles in the rocket nozzle which allowed them to keep the large single chamber but at the expense of power because they took up space that would otherwise have been filled with more injector holes for fuel and liquid oxygen.

The Four chambers of the RD-170 supplied 7900 kilo-newtons of thrust in a vacuum: even more powerful than the 7700 kilo-newtons of the F-1. Soviet engineers also achieved higher chamber pressures in the RD-170 than equivalent American engines, resulting in greater fuel efficiency from the ground.

In 1986, after ten years of development and testing, ‘Energia’ was ready for launch. But as the rocket neared completion, there remained one problem: ‘Buran’ was still years away from being ready. To test the new Soviet launcher, a repurposed ‘TKS’ module was loaded with science experiments, including elements of the ‘Skif’ CO2 laser weapon. The 80-ton payload was given an ominous black coat of paint, and named ‘Polyus’.

When ‘Energia’ lifted off for the first time on 15th May 1987, the huge rocket set off at an angle. Fortunately, three seconds later the guidance system corrected the trajectory, continuing a path up into the sky as planned. ‘Energia”s first launch was a success: the payload separated at its target altitude, ready to carry out a brief orbital insertion burn. However, due to a sensor malfunction, ‘Polyus’ rotated further than intended before its burn, falling back into the Pacific Ocean.

Still, Glushko’s monster Rocket had shown that it could do what the ‘N1’ could not. The USSR now had a proven Super-heavy lift launch vehicle, and the next task was to use ‘Energia’ to launch ‘Buran’. On November 15th, 1988, one year before the fall of the Berlin Wall, the pride of the Soviet space industry was prepared on the pad for the long-awaited maiden flight. The first test was to be an unmanned mission operated entirely by its on-board computers.

At 8am local time, ‘Energia’ lifted its orbiter to an altitude of just over 250 kilometres. ‘Buran’ orbited Earth twice in a little over 3 hours, then slowed to re-enter the atmosphere. Here it’s automatic systems detected high crosswinds and it made a second approach the airfield at Baikonur. Even battling a strong cross-wind, ‘Buran’ touched down just 10 metres from the target mark on the runway.

Images of ‘Buran’s maiden flight shocked and impressed the world, who hadn’t imagined that the USSR could build their own shuttle. But plans were already in place to go further, with a second orbiter, ‘K2 Ptichka’ (or ‘Little Bird’), scheduled to launch in 1991. A third orbiter, ‘K3 Baikal’ (named for the world’s deepest lake in Siberia), was to make the first manned flight in 1994.

An improved ‘Energia II’ rocket system was also planned, which would be fully reusable and capable of launching to the moon or beyond. The centre core booster would use Sangers 1933 antipodal aircraft method to skip off the upper atmosphere to makes its way around the world and back to the launch area. The detachable boosters would fall away and open their folding wings and be able to glide like a plane back to an airfield all of which make SpaceX look like latecomers to the reusable rocket party.

But sadly, both ‘Buran’ and its huge rocket would never fly again: by 1989 the USSR was already beginning to unravel. When the Soviet Union broke up two years later, ‘Buran’ and ‘Energia’ gathered dust in long-term storage. In many ways the Buran and the Energia were a solution to a problem that no longer existed and something that the new Russia could not afford.

As the new Russian space program struggled to raise funds, ‘Buran’ and ‘Energia’ were displayed as a gargantuan exhibit to impress tourists and media who visited Baikonur. However, by 2001, poor maintenance had led to water leaking through the roof of Building 112, onto the spacecraft 75 metres below.

On 12th May 2002, a repair team climbed onto the roof, after heavy rains. At 9:20 in the morning, with a huge crash, the roof collapsed, completely destroying ‘K1 Buran’ and ‘Energia’. Eight workers were also killed.

Although the vast costs of developing ‘Buran’ might appear to have been a tragic waste, the technological legacy of ‘Energia’ lives on. Variants of the RD-170 engine are currently in use on the current family of ‘Zenit’ rockets. The American ‘Atlas 5’ First Stage is also powered the RD-180: another adaptation of the remarkable design.

After the Space Shuttle Columbia disaster in 2003 and the grounding of all the US shuttles, it was wondered whether the buran could be brought back but by then both the vehicles and equipment had fallen in disrepair or had been used for other projects. In 2011 when the US shuttles were retired the idea was floated once again as a cheaper way to gain a shuttle service instead of designing a new vehicle from scratch, but it again came to nothing and the dream of a Russian Space shuttle went the same way as the US one.

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