Tuesday, February 28, 2017

To the Moon!

SpaceX is going around the Moon.

The projected date is late 2018, but that's ambitious (as all SpaceX dates are). I believe Elon when he says that Dragon 2 will fly next year, but going from first test cruise to Moon trip in a single year is ... ambitious (there's that word again).

But regardless of whether it's in 2018 or 2019, this is very cool. This is going to be the kind of spectacle that will make a lot of people sit up and take notice. Whoever these paying customers are, they'll go down in history as the first private citizens to fly beyond Earth orbit.

And that's a good thing. NASA has been futzing around for years with their SLS and Orion programs, wasting billions, and they don't have a single rocket to show for it yet. The first planned test launch to LEO is for late 2018 (and then it plans to fly again in 2021 (woo!!)), the same time that SpaceX plans to be flying tourists to the Moon. And from there things don't improve for SLS, as their projected flight tempo is one flight every 2-3 years at a cost of $1-2 billion per flight (depending on how you accrue program development costs). Those sort of costs are great for the cost-plus contractors that fund Congressional campaigns, but if the rest of Congress (who doesn't get kick-back money from SLS contractors) starts paying attention they might start to ask why NASA is paying 10x as much for a rocket that flies 1/20th as often as Falcon Heavy.

What you'll surely here next year though, in defense of SLS, is that Falcon Heavy doesn't have enough power to launch a Moon lander or Mars lander. "We need SLS if we want to actually land anywhere, and not just do fly-bys!" they'll say. And that's true to an extent. The Falcon Heavy doesn't have enough power to land a crewed Dragon 2 on the Moon as long as you have to launch all your fuel at the same time.

The mass of the fuel needed to land on the Moon and return is the limiting factor. As long as we keep sending up the fuel and the crew vehicle on the same rocket, we will need to keep building ever larger and more expensive rockets.

But this is not actually necessary. The current Dragon spacecraft can berth (aka, get close and then be grabbed by the Canadarm) with the International Space Station, and Dragon 2 will be able to dock (aka, mate with a docking port using its own propulsion; no Canadarm necessary) with the International Space Station. A craft that can do this can also dock with an external fuel tank in orbit.

So watch for that, because while circling the Moon will be the big bang of 2018 (or 2019), refueling in orbit will be the prelude to the next one.

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