Post by Dan Tilque Post by J. Clarke Post by Dan Tilque Post by Lynn McGuire
"Elon Musk: Starship Will Fly for 20-30 Years, Aiming for Fleet of 1,000"
"The goal, according to the tweets is to have a fleet of about 1,000
Starships in service. Musk believes the company will eventually be able
to produce 100 vessels per year, and each hull should be good for 20-30
years of service. With that many ships, SpaceX would be able to
transport up to 100 megatons of cargo to Mars every year. That’s the
equivalent of 100,000 passengers."
Wondering if they've figured out how to get all that tonnage down to the
surface. That's actually one of the most difficult parts of exploring
Mars. NASA hasn't found a way to get more than about one ton down safely.
The same way they get it to Earth. Starship uses propulsive landing,
just like Falcon 9.
I just googled about this and found a video of Musk explaining how
Starship is going to land. It's basically going to use air resistance to
slow itself down, but use lift to stay in the upper atmosphere to keep
from overheating until the velocity gets low enough. Then it'll come in
for a powered landing.
However, he was clearly talking about landing on Earth. The problem with
Mars is that its atmosphere is way too thin to do this. That's the
problem NASA has.
He was talking about landing, period. Landing on Mars and the Moon
are part of the specs. Starship can land on Earth. Mars has 1/3 the
gravity and half the entry speed. Further, Starship can land on the
Moon, which, while it has half the gravity of Mars, also has no
atmosphere at all.
Post by Dan Tilque
They've used several different methods. Big parachutes can only slow
small vehicles down. There's just not enough air to slow down big ones.
The did a bouncing ball landing with Sojourner, but there's limits to
how big that can get and not splash. Plus you don't want to land people
in that; too many gees in the first bounce. Finally they used that
complicated landing for Curiosity, which let them land a somewhat bigger
payload, but it's still limited. And there's too many moving parts for
that to be extremely reliable.
Remember, NASA couldn't land a booster that had been used to launch a
payload to orbit. Don't use NASA as any kind of guide. At this point
SpaceX has forgotten more about powered landing of rocket vehicles
than NASA has ever known. This isn't some huge insoluble problem.
You can aerobrake to x speed. Then you have to decelerate with
rockets from there down. From that point it's all design.
Also remember that SpaceX isn't trying to do things the NASA way.
Starship is fully fueled when it departs Earth--any fuel that was used
getting into orbit is replenished first. If necessary a tanker can be
sent to Mars and it can refuel on orbit before landing. When you have
a fleet of spacecraft including reentry-capable tankers you can do
things like that.