** The Official Space Flight Thread - The Space Station and Beyond **

Richard - London said:
How is that different to when something goes wrong on a plane?
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Engine failure on a plane isn't a death sentence is it. Planes are one of the safest modes of transport today. For the first few decades they weren't. Still at least they can glide. If something goes wrong with the booster or Starship they are all dead, it can't glide, it can't land without its engines and it can only land vertically and at the moment it can only land by being caught off the ground.

At least with Dragon there is in flight abort system, it leaves the failing rocket and floats back to Earth on parachutes.
 
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Look at the speed it enters the frame at vs how much it slows down before landing, the thrust is off the charts :cool:


In the future when they're taking off and landing from other moons and planets, the whole process will need to be re-done because each one has its own gravity which needs to be accounted for, air thickness etc. Crazy thinking about it.
 
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mrk said:
Look at the speed it enters the frame at vs how much it slows down before landing, the thrust is off the charts :cool:


In the future when they're taking off and landing from other moons and planets, the whole process will need to be re-done because each one has its own gravity which needs to be accounted for, air thickness etc. Crazy thinking about it.
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It's not called a Suicide Burn for nothing.

Some numbers for reference - the rocket's mass is about 25 tons, but it carries about 400 tons of fuel which is almost expended by the time it lands. Each engine develops about 100 tons of thrust so it's not surprising it only needs one engine lit at ground level. It's an amazing engineering accomplishment.

Mars is an interesting one for landing - it has much lower gravity than Earth, and the atmosphere is extremely thin. So thin that you really can't use it for decent aerodynamic braking, but not SO thin that you can just ignore it.

 
Penfold101 said:
Mars is an interesting one for landing - it has much lower gravity than Earth, and the atmosphere is extremely thin. So thin that you really can't use it for decent aerodynamic braking, but not SO thin that you can just ignore it.
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I think maybe Scott or maybe Elon said they'd have to do more than 1 orbit to use the limited atmosphere as a way to bleed off velocity on Mars.
 
Colonel_Klinck said:
I think maybe Scott or maybe Elon said they'd have to do more than 1 orbit to use the limited atmosphere as a way to bleed off velocity on Mars.
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The Mars Reconnaissance Orbiter used the technique - it took 6 months to go from 35 hours to 2 hours.

I've done it a lot in KSP too - how useful it is depends very much on the size of your testicles...
 
Speaking of Mars, this popped up on my feed, imagine being the short stay crew, circling Venus on the way for a gravity assist :cool:

How I wish I got into space as a career path, maybe it's still not too late in some way :p


Assuming DRACO goes online, then 45 days to mars is rather compelling too..
 
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Smarter Every Day new video of a talk he did about Artemis at American Astronautical Society. He mentions a new paper that says Starship for Moon landing will require 15 launches to fuel it in LEO. How can that number work? That will have to be 15 launches in maybe 3 days given that boil off will be continuous and the longer it takes the more boil off. How many Starships will be built as refuel ships? This plan just seems to be years away from working.



(edit: I will say I'm only 45 mins into the video as I have to go out, maybe he solves this problem later in the video which I'll watch later)
 
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You mean the refuel process that no-one has ever tried with Starships that need to dock in orbit over and over again, which no-one has ever tried, assuming they manage to get one into a stable orbit, which they haven't managed yet? Nope, can't see a problem with that myself.
 
Colonel_Klinck said:
Smarter Every Day new video of a talk he did about Artemis at American Astronautical Society. He mentions a new paper that says Starship for Moon landing will require 15 launches to fuel it in LEO. How can that number work? That will have to be 15 launches in maybe 3 days given that boil off will be continuous and the longer it takes the more boil off. How many Starships will be built as refuel ships? This plan just seems to be years away from working.



(edit: I will say I'm only 45 mins into the video as I have to go out, maybe he solves this problem later in the video which I'll watch later)
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Would it be easier to have a hypergolic propellant version of the starship moonlander so they could take longer to refuel it.
 
drakulton said:
Would it be easier to have a hypergolic propellant version of the starship moonlander so they could take longer to refuel it.
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That might well be simpler but they'd need Raptors that work on that fuel.

Its going to be interesting to see how they are going to solves this problem. Are they thinking of building a "gas station" in LEO that can keep the liquid oxygen and methane at cryogenic temps so Starship can just launch and refuel at that rather than wait for 13 launches to give it the fuel it needs.
 
Colonel_Klinck said:
That might well be simpler but they'd need Raptors that work on that fuel.

Its going to be interesting to see how they are going to solves this problem. Are they thinking of building a "gas station" in LEO that can keep the liquid oxygen and methane at cryogenic temps so Starship can just launch and refuel at that rather than wait for 13 launches to give it the fuel it needs.
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So..... not keeping it simple then?
 
Just goes to show that we really need to wean ourselves off of chemical rockets for spaceflight and start to embrace nuclear. Launch to orbit, yes use chemical but once in orbit switch to nuclear.
 
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Colonel_Klinck said:
That might well be simpler but they'd need Raptors that work on that fuel.

Its going to be interesting to see how they are going to solves this problem. Are they thinking of building a "gas station" in LEO that can keep the liquid oxygen and methane at cryogenic temps so Starship can just launch and refuel at that rather than wait for 13 launches to give it the fuel it needs.
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Can you imagine the size of something like that and the launches needed to keep it filled?
 
Malevolence said:
Just goes to show that we really need to wean ourselves off of chemical rockets for spaceflight and start to embrace nuclear. Launch to orbit, yes use chemical but once in orbit switch to nuclear.
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Indeed a nuclear powered plasma engine or similar would have huge ISP and could acceerate very sowly but constantly for weeks at a time. You still need the big rocket to reach orbit. Starship looks like a good contender for that role. Once you have a nuclear powered ship it can become a tug for all sorts of missions, just top up the reaction mass and off you go again.
 
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