Launch combinations

Currenmtly launch combinations are commonly on topic a little bit. One of them is the launch of an Earth Departure stage plus separatedly launching a crew vehilce which both dock to each other and depart for the moon then.

But a thread in the section about the space activities of the russian government mentions another method which seems to deserve discussion in my eyes.

The idea there is to launch first a module enabling in-orbit-operations and then launching the crew module which docks to the operations-module. The crew module reenters later while the operations-module remains in orbit and - sufficient fuel and propellant provided - can be used by another mission again.

To me it seems that this way weight and thus propellant of and for the crew module can be saved. And it could assist reusability perhaps.

What about that?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

The Russian idea of using an on-orbit space tug has been put forward before, not normally when dealing with manned vehicles though.

The reason for this change was primarily so that Kliper's weight would be reduced and it could launch on a smaller booster, possibly from Kourou on a new Soyuz.

IMO I do not think that this method is suitable for manned craft as it complicates things unnecessarily. In the case of a manned flight to the ISS it would require 2 rendezvous/dockings instead of the usual 1, once with the space tug and once with the ISS itself. Also if the tug remained in orbit there is the need for refuelling and maintenance of the craft.

You have hit the nail on the head. That is why reusable is more difficult than expendable. No maintenance is needed if you only use the vehicle once.