Great article Chris. It's sad however to see how the naysayers have immediately pounced on the "we don't need no HLV" theme once again instead of trying to stick to the core of the article, which is how the gateway station opens up the possibility of deep space reusable spacecraft having a home in cis-lunar space. While your article relates how the SLS could be used to create and utilize the station, it was clear, at least to me, that it was not about the HLV, but was rather about the EML-1 station itself and what it would do for opening the lunar surface to us once again. For example, launching a lunar surface mission from the Gateway station allows the lander to literally go *anywhere* on the entire lunar globe, near and
far side, with anytime return. We can't do that with missions launched from earth orbit.
Once operational servicing, launching and receiving returning reusable landers, the possiblilties for BEO exploration begin to get one thinking. For example there is no reason the reusable lunar lander could not, over time, grow in size and capability, nor anything preventing the gateway station itself, again over time, evolving in capacity and capability. We may even eventually have several landers stationed there, each one in various stages of refurbishment and outfitting for various surface missions. If the Gateway station is international, like the ISS, the landers could be from the various member nations for their own -or combined- lunar exploration programs. All their crews would have to do is get there in smaller spacecraft designed for ferrying service. It could well become the home for Nautilus style solar system exploration spacecraft, perhaps even 2 or 3 of them, which would allow so much flexibility in BEO mission planning, again, with international crews. Having a station at EML-1 truly is the gateway capability that opens the solar system to mankind, beginning with a small reusable lunar lander stationed and serviced there. Over time it will, like the ISS, grow in size and capability. People forget that the station, exactly like the ISS, really is a spacecraft in its own right. If we do go this route, and I hope we do, I hope the station designers consider physical expansion capability in the core design, so that the station itself can be adapted to growing exploration needs as we move on. It doesn't need to start out being huge, just capable of becoming so, when and as budget allows. I can envision the possibility that the station begins life as a man-tended spacecraft, being visited to prepare a lander for a lunar surface mission before execution, and eventually becoming a permanently manned spacecraft servicing several BEO deep space spacecraft, in much the same way the ISS is permanently manned for research work.
Taking this a bit further, I can also envision an ISS replacement whose function is to assemble, repair and refurbish BEO spacecraft, sending them to the Gateway station and retrieving them for rework or repair after mission complete via SEP tugs. These same tugs would then return them to the Gateway station for multiple missions launched from and returned to EML-1.
I know this line of thought gets way beyond your excellent article, but that's what happens when one reads something as well worded and researched as this. Sorry about that
Thanks to the sources and to you.
Great article Chris. Hopefully it will stimulate some genuine forward thinking about what a gateway station such as this could mean for all of us.