Jeff Foust, for SpaceNews, on NASA studies of human-class lunar landers:
“There are many different ways you can look at architectures for landings: single-stage, two-stage and three-stage landing options,” he said.
The drawback with the single-stage approach, he said, is the mass of the spacecraft, which would exceed 50 metric tons. “They’re actually in excess of what our SLS is capable of,” he said.
A three-stage approach involves the addition of a transfer stage, or tug, along with the ascent and descent modules. The transfer stage would move the lander stages from the Gateway to a lower orbit, reducing the amount of fuel they have to carry and thus making them smaller.
That three-stage approach, he said, spreads out the cost of lander development and allows NASA to “lean in hard with the commercial sector” on the descent stage in particular. “We can focus more on the ascent element” and its human-rating requirements, he said. Both the ascent and transfer stages could be designed to be reused.
Read the entire article by Foust, and you’ll likely be struck with the same feelings I have: appreciation that NASA has to figure out how to make an exploration program out of what fits in the budget, and the utter disbelief that a piecemeal effort as disjointed and dysfunctional as this is something anyone can believe in.
It’s single-stage-or-bust for me, but I could be convinced of two-stage as a first step. Being forced into a three-stage lander is a clear sign that there are fundamental issues with every piece of the system.