r/SpaceXLounge

Boeing have floated the idea of using an SLS for a one-shot MSR campaign (1 booster and 1 spacecraft) - direct to Mars, and direct earth return.

Should save a lot of time, money, and complexity. Based on the recent SpaceX test flights - SH is pretty capable at getting things into space at this point. Starship probably isn't ready to launch such a complex payload into space though?

I was wondering if you could use SSH or just SH maybe with a modified Centaur / ICPS to launch the Boeing proposed spacecraft?

Would be presumably cheaper than using SLS and you can just crash the booster into the ocean. What do y'all think?

Please bear with me,it's my first post and I'm following the developments of SpaceX and NASA only since they started testing Starship, so I'm pretty new to this.

We (humans) are getting more interested in other planets and deep space and are taking more and more steps to actually getting there. It made me wonder what the worst case scenario would be for people on board a ship in space. I came up with the following:

Starship is on its way to Mars with x-amount astronauts on board but due to a technical difficulty (maybe a stuck 'pedal to the metal'), the ship loses control en sets course towards deep space. It does have electricity, it does have oxygen and it does have (limited) food supplies. I'd imagine that astronauts would have been trained for such worst case scenario, and what would they do? And are they already taking account for such a scenario during previous and present launches?

I know that e.g. fighter pilots have some sort of pills for when they crash in enemy territory to make it quick. Would that also be something astronauts would take with them?

Bit of a dark one, but I would love to hear your ideas and knowledge! :)

Sorry if I missed this, I did some searching but didn't see a lot of discussion.

When SpaceX does a real propellant transfer test, you'd have a starship in orbit with significant propellant. Could they do anything useful or interesting with this like head towards the moon?

I know it wouldn't be fully loaded in the future sense (which takes multiple propellant refills) but curious if even 1 load up sets up anything interesting for after the demo.

Interviewing on site next week. Would be making the move to Florida from up north. Anyone have any big complaints about working there? Seems the few people I know seem to love the place.

Interesting side by side

Edit: I think I'm no longer confused, d. seems like the reasoning is not wildly wrong, and /OlympusMons provides a technical explanation that arrives at the same conclusion.

I noted that during IFT-4, both booster and ship had only a sliver of propellant left after completing their primary burns.

I'm not sure how much extra propellant is burned to loft a 100t payload but naively assume its a decent chunk.

I also didn't notice the commentators mention anything about propellant venting.

So Im confused/curious and a casual Google didn't turn up anything. Would anyone in the know be able to enlighten me?

Possibilities as I see them:

a. Less propellant is loaded than the maximum to allow for no payload. This seems unideal from a testing POV and I imagine would be actively communicated, so I am mostly discounting this option.

b. Venting is taken place, just not mentioned / I didn't notice.

c. Changes since the original starship design have eaten up all the margin, and the current vehicle is actually not capable of getting anything close to 100t to orbit. So the stretched versions of starship aren't just an upgrade but at this point are necessary for the system to be a viable launcher. This would also explain why they're listing the current payload capacity as N/A and aren't using a dummy payload.

d. (Edit, and apologies for thinking out loud) Most of the penalty of extra payload is the extra fuel required. Since they are already paying the penalty by loading to the hilt, maybe it does indeed only require a tiny extra silver of propellant to actually take a payload.

But while the difference between (only ship to orbit fuel + empty ship mass) and (ship to orbit fuel + payload to orbit fuel + ship empty mass + payload mass) is much larger than just the payload mass, the latter is still ~8% of the ships wet weight. So naively expect 8% of fuel left over.

But in that scenario, the ship is burning less fuel as it ascends, offsetting the fact it's lighter due to no payload. Assuming the offset is essentially total, the amount of extra fuel could naively be expected to be around the expected payload, or ~50-100t (as pointed out below, starship expected payload is currently stated at 50t).

50t is ~4% of total fuel. This would not be inconsistent with the amount shown by the livestream telemetry given its low resolution.

Does that reasoning hold? I might need to go learn basic rocket maths...

Lets say you're trapped in a..steel..cage (the bars are just close enough to trap you, so not good protection), how close could the average person get to the Starship launch and survive? How far away would it blow your eardrums? I watched the Everyday Astronaut Slo Mo and Audio video and it shows how violent it is close to stage 0..don't think anyone is surviving that.

I know this must be true because people far smarter than me talk about it like it's an obvious problem. But the concern is that the fuel and oxygen in the Starship tanks must stay at cryogenic temperatures or it will "boil-off" and slowly disappear. What is happening here? I thought that when you have a pressurized fluid it cannot boil away if the fluid has no where to go. Is the problem that the tanks aren't strong enough to hold the pressure? Does the boiled gas "leak" through the container when it is in gas form? Are there leaks in the valves that make this unavoidable?