Let’s face it, Soyuz is getting old. It’s not that the spaceships themselves are getting rickety, there have been many incarnations, but the original Soyuz design was first conceived in 1966, so the Russian space agency (Roscosmos) is feeling it’s about time for a change. Soyuz has carried out the most manned missions into space out of any other space flight system (over 100 since the 1960s), so Russia has every right to be proud of its achievements.

So what system does Roscosmos want to replace Soyuz with? Perhaps a bigger version of Soyuz? Perhaps a revolutionary winged spaceplane? Nope. They are currently looking at plans for a Soyuz-esque capsule that will re-enter the Earth’s atmosphere much like before. But due to political pressure (spawning the need to move Roscosmos’ operations out of Kazakhstan), engineers must find a way to land the return vehicle in a minuscule area. Measuring only 2×5 km (yes, that’s a tight 10 km2), the landing strip will be as unforgiving as the new method to land the descent vehicle.

There will be no parachutes and no wings; the new concept will use a rocket-powered landing system alone, creating the first ever rocket-powered Earth-lander. If you thought that was a rather extreme design specification, you might be surprised to hear that engineers want to start firing these landing thrusters when the descent module is only 600-800 metres from the ground…





All previous Soyuz descent capsules have been slowed via a combination of atmospheric drag (hence the need for ceramic tiles to withstand the extreme heating inflicted on the vehicle), parachute-aided descent and then a small burst from a solid rocket to ensure a soft landing. Apart from a few ballistic re-entries, and a few early fatalities (Soyuz 1 and Soyuz 11), this system has worked well.

Unfortunately for Roscosmos, Moscow has decided to move space launch and landing operations out of the newly independent republic of Kazakhstan to a new spaceport being constructed in eastern Russia. This imposes a huge design restraint on the new spaceship, it can’t use the vast wilderness of Kazakhstan to parachute into. The current primary landing zone for Soyuz is 25×30 km, making a reasonably-sized target for the descent module to aim for. Even during the bungled April 2008 hard landing, where a ballistic re-entry forced the Soyuz descent module to miss the 750 km2 landing zone by 400 km, at least there was plenty of flat Kazakhstan to bump into.

The new landing zone will be 1.3% the size of the old one, meaning the new landing system will have to be more precise than a parachute-aided landing. Cue the rocket-powered precision landing descent vehicle for Russia’s next generation spacecraft.

Although I love the artistic rendering of the spaceship in orbit and the descent vehicle (the panels riveted together and scorch-marks are a special gritty pleasure for me), to rely on a rocket powered landing seems a little risky. This next generation descent vehicle will have one of the most insane landing profiles I have ever thought possible (“possible”? I use that word very lightly). Basically, using atmospheric ablation to slow it down in the first instance is perfectly fine, Soyuz does, as does the Shuttle, but it would appear that the plan is then to allow the vehicle to fall, at terminal velocity, to an altitude of 600-800 meters before igniting it’s landing rockets.

Hold on. Meters? Yes, meters.

According to the presentation made by Nikolai Bryukhanov, the leading designer at RKK Energia, at the 26th International Symposium on Space Technology and Science in Hamamatsu, Japan, the spacecraft would fire its engines at an altitude of just 600-800m, as the capsule is streaking toward Earth after re-entering the atmosphere at the end of its mission. — BBC News

I spat my coffee across the keyboard too.

But it’s OK, the “precision landing motors” will fire at 30 meters, to guide the lander to the 10 km2 landing strip. If one of the landing rockets didn’t fail (or slightly under-perform) that is.

Call me cynical, but I’d be happiest if I could glide into landing on a huge airstrip. If I don’t have that, parachutes would do. Preferably three of them, in case one fails, at least the other two will ensure I don’t end up pancaked inside a flattened chunk of smouldering metal. Hard landings do happen, regardless of how robust a system is, but to depend wholly on a rocket-powered breaking system to get cosmonauts and astronauts back to Earth seems a little extreme.

Perhaps the design of the landing strip needs to be looked at, designing the space vehicle around a landing strip probably isn’t the best way to go. Apparently, I’m not the only skeptic, but the design is obviously being considered. Rocket-powered manned landings have been achieved on the Moon, there have been a few US and Russian designs incorporating rockets and rocket engine technology is becoming more and more reliable. However, to control the descent of a free-falling space vehicle, bringing it to a stop within 800 meters from the ground leaves little (if any) margin for error.

Source: BBC