Several weeks ago, I blogged about how Jeff Bezos has managed to get his New Shepard launch system to take off and then land vertically back on the launch pad. The ability to recover and reuse a rocket is a major breakthrough in human exploration and exploitation of space. The lower cost of launch and the ability to relaunch rapidly will be a boon to the space industry.
I have covered a lot of different propulsion systems in this blog for launching payloads into Earth orbit and beyond. These either carried all their fuel or carried fuel and relied on oxygen in the atmosphere for the first part of the launch. However, there are a lot of other systems for launching space missions in which the actual power for the launch is external to the launch vehicle.
Solving two problems with one action is an attractive prospect. There is an old folk saying that covers this idea. "Kill two birds with one stone." It often save money, time and effort over solving two problems independently. The junk in Earth orbit consisting of debris from launches and dead satellites is building up to the point where it may become more difficult to launch space missions. It is estimated that there are over half a million pieces of debris in Earth orbit.