UNITY XXI MAKES THE FIRST RENDEZVOUS

KSP - Year 3, Day 240

Bob and Tomdun make a first in the entire Space Program to date by meeting each other in space. The rendezvous took place nearly five hours after Bob launched in Unity XXI and both ships came within seven meters of each other at their closest point. By this time, Tomdun had already spent over a day in orbit - the longest yet by a Kerbal.

'It is vital that we know how to get two ships to rendezvous up there in space,' said Gene Kerman. 'The method we are working towards for the the Mun landing requires us to do just this. So that's what we aimed to do. And we did it.'

A view of Unity XX as Unity XXI approached the craft

However, the mission wasn't perfect. During launch a mis-calculation meant that Unity XXI, piloted by Bob, overshot the marker and lead Unity XX by an uncomfortable distance. Mission Control decided to widen XXI's orbit to slow the craft down, allowing Tomdun to catch up. The mistake meant that the rendezvous wasn't perfect and a heavy amount of fuel was used.

However, the two craft did eventually meet up and then spent the next few hours practicing station-keeping maneuvers in orbit. The mission was marked as a success and checked off another vital step in the Mun program.

Artists impression of the two craft meeting in 

orbit, resulting in the first two vehicles ever to do so

However, the situation worsened when it was time to break formation and head back home. Tomdun remained in orbit to complete his three-day endurance flight to test both himself and the hardware used for the mission. Bob would come directly back to Kerbin. But due to the excessive fuel used during the rendezvous, Mission Control were forced to switch to emergency reserves used to stabilise the craft before and during re-entry. But when groundcrew went through the re-entry check-list, it became evident that Bob still did not have enough fuel to return home to Kerbin.

'It was the most uncomfortable silence I have ever endured,' Gene said slowly. 'CapCom got Bob to repeat his gauge readings three times before it sunk in. We did not have the fuel to get him home.'

Every engineer possible was assembled and meetings were held within hours. Bob had enough oxygen and energy for several days. But none of that mattered if he couldn't get home.

'All sorts of things were discussed. At that point, we didn't care how we got into that situation. All we knew is that we had to get out of it. The safest way was decided when we realised we had enough fuel to dip into the atmosphere during a small part of the orbit.'

The technique of aerobraking had been tried once before when the ITAD satellite skimmed the atmosphere during a small phase of its orbit. Over time, this caused the probe to sink further toward the ground with every pass and, ultimately, fall back to Kerbin.

'We had the fuel to get the craft down to sixty kilometers, leaving a little reserve for re-entry stabilisation. Then all we had to do was let friction do it's work on the capsule.'

Unity XXI launched a little too hastily on its way to meet Unity XX

In the end, it only took four orbits before the capsule reduced it's speed enough for re-entry. Bob splashed down safely, albeit a little off-target. Tomdun remained in orbit for nearly two more days and splashed down after a record-breaking three days and eleven hours in space.