LAST TRY: ZOND 6

Just over a week later, Zond 6 headed away from Earth onto a moon trajectory (10th November). Several cosmonauts attended the launch, some hoping that one day soon they would fly a future Zond. The problems from the earlier missions then reasserted themselves. The Earth sensor failed and then the high-gain antenna failed to deploy. Despite this, two days later Zond 6 adjusted its path and on 14th November rounded the moon at a close point of 2,418 km with its automatic camera clicking away and taking metres and metres of photographs of the moon’s surface. Zond 6 carried a similar payload to Zond 5: 400 mm camera, cosmic ray sensor, micrometeorite detector and some unidentified animals (probably turtles again).

Even as the mission was in progress, the Russians were well aware of the start of the countdown for Apollo 8 at Cape Canaveral. The head of the cosmonaut corps, General Kamanin, considered the Apollo 8 mission to be pure adventurism and an extraordinary risk. He then considered a Russian manned flight around the moon to be a possibility for the first half of 1969. But, he conceded, the Americans might just pull off their mission first. There were hurried phone calls from the Kremlin: Can we still beat Apollo 8? No, said Kamanin. The best we could do is a manned flight in January, assuming Zond 6 is a success and Apollo is delayed. The most realistic date for a manned circumlunar mission was April 1969. The leaders of the space programme would not be rushed. The Soviet approach – four successful Zonds first – was clearly more conservative in respect of safety.

Zond 6 was now returning to Earth, though more problems emerged. Cabin pressure in the descent module suddenly fell, but then held. Temperatures in the fuel tanks fluctuated up and down. Zond 6 did manage to fire its engine briefly on 15th November, 251,900 km out, to adjust its course home and again a mere 10 hours before reentry to refine its trajectory. Zond 6 reentered over the Indian Ocean and dived to 45 km altitude. Pointing its heat shield at 90° to the flight path generated a cushion of lift underneath the Zond, bouncing it back into space. It was skipping across the atmosphere like a stone skipping across water, its speed now down from 11 km/sec to 7.6 km/sec. Zond 6 soared back into space in an arc and several minutes later began its second reentry. At this stage, things began to go awry. First, the high – gain antenna failed to separate. Second, more seriously, a gasket blew, depressurizing the cabin while it was still in space – which would have been fatal if unsuited cos­monauts had been on board and certainly did kill the animals on board at this stage. Third, between 3 km and 5 km above the ground, a spurious electrical signal com­manded the firing of the landing retrorocket and the ejection of the parachute. Zond 6 crashed to the ground from a great height unaided. Unlike the first Soyuz, it did not explode on impact, but any spacesuited cosmonauts on board would have died. It took ground crews a day to find the cabin. They salvaged the film, which was then exhibited to the world as proof of a completely successful mission. Only decades later was film of the badly battered moon cabin released and the truth of Zond 6 told.

Zond 6 was a triumph for the skip reentry trajectory first plotted ten years earlier by Department # 9. However, the performance of Zond 6 to and from the moon still needed some improvement. The landing accident was so serious that more work was still required on the landing systems, which had been considered solved by the smooth return of Soyuz 3. Sadly, the Russians did not learn their lesson as a result of the depressurization high above the atmosphere and put cosmonauts into spacesuits for such critical manoeuvres. The crew of Soyuz 11 later paid the penalty for this failure to learn. As for the planned flight around the moon by cosmonauts, it was postponed.