With the arrival of the new Destiny laboratory module, the young International Space Station had more room to grow and for astronauts and cosmonauts to get busy on experiments. But only five of the 24 equipment racks were pre-supplied by STS-98.

Between STS-98 and the next Shuttle resupply mission, the Expedition 1 crew busied themselves with experiments and transfer of fuel and supplies from a new version of Progress-M unmanned Russian supply spacecraft, which docked to the aft port of Zvezda on February 28, 2001. Before the supply craft’s arrival, the three members of the Expedition 1 crew re-entered their Soyuz TM-31 ferry spacecraft, undocking and flying it  from Zvezda’s aft port to re-dock at Zarya’s nadir port. This was necessary because Progress must use the attachments found only on Zvezda’s aft docking port for resupply of propellants, water, gases and the like.

After Progress M44 departed with trash and other unneeded equipment to deorbit and burn up in the atmosphere one and a half months later, the Soyuz ferry was returned to Zvezda’s aft port. This ballet of Russian ferry and supply ships would continue somewhat in the station’s early life until the Russian segment of the station was later equipped with an additional airlock and docking port.

The next visiting vehicle, STS-102, would add seven additional experiment racks to the laboratory and provide additional supplies to the station. However, the equipment racks were too large and cumbersome to be stored and moved from the crew compartment of Atlantis and through its comparably narrow docking tunnel. To get these items into the ISS required a more efficient transfer method.

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Leonardo during preparation. (NASA photo)

Enter Leonardo, one of three pressurized Multi-Purpose Logistics Modules built by the Italian Space Agency, which added more internationality to the new ISS. Shaped like an ISS habitable module but with only one CBM port and no windows, Leonardo (and, on later missions, it’s twin, Raffaello) was large enough to hold equipment racks and far more larger supply packages that could not be effectively moved through the comparatively tiny tunnel of a Pressurized Mating Adapter and prior SPACEHAB pallets.

Yes, there was also a third module, Donatello, which would never fly. Apparently the ISA was fond of same names that were also popular for some comic book adolescent amphibian ninjas.

STS-102 launched on March 8, 2001, arriving at the station on March 10.

Before Leonardo could be mated to the nadir CBM port of Unity, it was time for another move of a PMU. This time, PMU #3, which helped Endeavour during Assembly 3A and the installation of the P6 truss and solar array, was now in the way. The starboard and port CBMs were too close in proximity to the new truss to be used for MPLMs.

Leonardo being guided to its berth using Discovery’s remote arm, as seen from a window within the station. (NASA photo)

On arrival, before any supplies would be transferred, the first order of business after greeting the Expedition 1 crew was to formally transfer a second important cargo on STS-102: the Expedition 2 crew: Commander Yury Usachov, Engineers Susan Helms and James Voss.

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The Expedition 2 crewmembers: Helms, Usachov and Voss. (NASA photo)

One at a time, each Expedition 1 member removed their fitted couch cushion from their Soyuz ferry spacecraft and their counterpart from Expedition 2 added their seat cushion to the Soyuz to complete the crew transfer.

This purposeful changeover procedure ensured that, in an emergency evacuation that could occur anytime, any crewmember would have an immediate spacecraft in which to escape, either in Atlantis or the Soyuz.

Leonardo was moved over to Unity. The simple, roomy design of the cargo container and the wide entrance of the Common Berthing Mechanism made supply transfer a breeze in microgravity.

Hyper-roomy Leonardo’s interior as a crewmember works on supply transfer. (NASA photo)

STS-102 added one external assembly to the station: An external stowage platform, one of many that would be added to the station’s exterior over time. These, as the name suggests, store tools and spare components that can be swapped out by crewmembers during an EVA or for use on future assembly missions.

Expedition 1’s crew would leave by Atlantis, leaving Expedition 2 with Soyuz TM-31. This first Soyuz ferry would stick around until April when another fresh ferry would be flown up by two other Russians and one unusual passenger.

With a new ISS crew and more supplies and experiments, the station was ready to gain a helping hand (and arm) for additional station assembly.

Next: Assembly 6A.