totm nov 2023 SpaceX Discussion Thread

[Minmus Taster]

20 minutes ago, DAL59 said:

Why has there been little discussion of using Starship for planetary probes? Wouldn't access to a cheap, super heavy launch vehicle allow missions like Dragonfly and the Uranus Orbiter to be much quicker by allowing direct routes instead of needing multiple gravity assists? I know Starship isn't an operational vehicle yet, but if NASA is willing to use it for as its plan for Artemis in just 2.5 years, why don't any missions slated for 5+ years in the future, when even pessimistically Starship will be available, plan to use it? A faster mission profile also reduces the plutonium requirements. 

In the case of the Uranus Orbiter (if it actually becomes a mission) the problem isn't just getting there, it's being able to slow down to get into orbit. Of course you want to be going fast enough for it to get there within a FEW presidential terms but also not so fast it can't insert itself into orbit once it's there. That's why no one has sent an orbiter that far, a recent study for a Pluto orbiter (much further than Uranus but still puts things into perspective) had the cruise phase for the orbiter taking nearly 30 YEARS to get there. Not to mention it needed like 5 RTG's to power it that long:

[darthgently]

16 minutes ago, DAL59 said:

Why has there been little discussion of using Starship for planetary probes? Wouldn't access to a cheap, super heavy launch vehicle allow missions like Dragonfly and the Uranus Orbiter to be much quicker by allowing direct routes instead of needing multiple gravity assists? I know Starship isn't an operational vehicle yet, but if NASA is willing to use it for as its plan for Artemis in just 2.5 years, why don't any missions slated for 5+ years in the future, when even pessimistically Starship will be available, plan to use it? A faster mission profile also reduces the plutonium requirements. 

I like Starship but it seems way overkill for a probe.  Maybe something like Zubrin's Mars Direct mini-starship, but autonomous, with the extra space devoted to more redundancy, sensors, and science?  Or maybe you mean the already planned probes launched as payload in Starship?

Anyway, here is a 2 year old vid of the Mars Direct concept with imagery of the mini Starship concept.  It is very Mars specific:

 

 

[DAL59]

5 minutes ago, Minmus Taster said:

In the case of the Uranus Orbiter (if it actually becomes a mission) the problem isn't just getting there, it's being able to slow down to get into orbit. Of course you want to be going fast enough for it to get there within a FEW presidential terms but also not so fast it can't insert itself into orbit once it's there. That's why no one has sent an orbiter that far, a recent study for a Pluto orbiter (much further than Uranus but still puts things into perspective) had the cruise phase for the orbiter taking nearly 30 YEARS to get there. Not to mention it needed like 5 RTG's to power it that long:

But you would also be able to have a greater mass budget of fuel for braking on the probe.

[StrandedonEarth]

32 minutes ago, DAL59 said:

But you would also be able to have a greater mass budget of fuel for braking on the probe.

Someone would have to run the numbers, and it would be a delicate balance, for sure. A shorter trip would mean a much longer insertion burn, or more powerful (heavier) engines. Would it still have the dV for a shorter trip, with all that extra fuel/engine mass? Many trade-offs, to be sure. At least it wouldn't need as many RTGs, maybe.

[AckSed]

8 hours ago, DAL59 said:

Why has there been little discussion of using Starship for planetary probes? Wouldn't access to a cheap, super heavy launch vehicle allow missions like Dragonfly and the Uranus Orbiter to be much quicker by allowing direct routes instead of needing multiple gravity assists? I know Starship isn't an operational vehicle yet, but if NASA is willing to use it for as its plan for Artemis in just 2.5 years, why don't any missions slated for 5+ years in the future, when even pessimistically Starship will be available, plan to use it? A faster mission profile also reduces the plutonium requirements. 

I think it's institutional inertia. Any mission using channels that aren't 'established' must wriggle around the bureaucratic blockages in the arteries of the whole organisation. They need champions on the inside, like Ingenuity, which was almost killed-off.

If you'll allow me a little rant here, no-one is prepared for what's coming when both StarShip reuse and in-orbit refuelling is proven out. No-one. Not. A. Soul.

NASA? As the monks in the cathedral apply the gold leaf to their metaphorical hand-drawn parchment, they're trying very hard not to think about the printing press, even as a few juniors in the back rooms marvel at the process.

The cubesat and smallsat builders? Not ready.

Universities and research organisations? Yeah, I think I heard about Starship...

Only a few in the commercial sector are thinking about it (e.g Varda and Sierra Space), and it's more about heavy-lift than the ability to send Starship off as a monster probe from LEO with a kick stage.

I suspect SpaceX isn't fully ready for it either. The hardware for the Mars mission before the colony will still need specialised equipment, and that is still but a dream.

[tater]

I think there are some true things above ^^^, but institutional inertia is sometimes pretty rational.

Starship, and the exact capabilities—and cost—are completely unknown entities. Yes it's probably going to work, yes, the cost to SpaceX will be low per kg, but there's no price competition yet, no pricing on a bespoke upper stage burning possibly hundreds of tons of propellant just for your probe to Uranus/whatever. Until we see FH vs Vulcan, vs SS, vs NG pricing? <shrug>

These more expensive, flagship missions take years to secure funding, then more years to actually develop and build. Even fast flight times can be years—then you (as the PI of a given instrument—and those guys got to be the PI because they've been around a while already) reduce the data, write some papers, then likely retire (the guy I'm thinking about at Los Alamos used the word "die" in place of retire).

So I think it needs to be more in play first—though I'd wager there are ideas floating around out there for planetary science where mass is less of an issue because of Starship.

[Flavio hc16]

12 hours ago, DAL59 said:

Why has there been little discussion of using Starship for planetary probes? Wouldn't access to a cheap, super heavy launch vehicle allow missions like Dragonfly and the Uranus Orbiter to be much quicker by allowing direct routes instead of needing multiple gravity assists? I know Starship isn't an operational vehicle yet, but if NASA is willing to use it for as its plan for Artemis in just 2.5 years, why don't any missions slated for 5+ years in the future, when even pessimistically Starship will be available, plan to use it? A faster mission profile also reduces the plutonium requirements. 

Someone did here's the https://www.google.com/amp/s/www.technologyreview.com/2021/12/07/1041420/spacex-starship-rocket-solar-system-exploration/amp/Article, ( and there was a open letter by some people at NASA talking about using starship and that NASA need to start to dream big).

 

Just to give an example:

a deep space  fully refueled V3  starship can give a 9KM/s DV to a  150 tons payload. 

And if that payload is a 15 tons probe, and 135 tons fuel with an engine with storable propellant that has 300 seconds of ISP, this gives the 15 tons probe 7 km/s, enough for a direct transfer and  propulsive brake to Neptune. With a probe 20 times heavier than voyager. But transfer time with a Hohmann is 30 years to get there. If we could speed up and down 0.5km/s (1km/s total) the travel time get cut to 12 years, and we would probably still talk about a 10 ton probe.

And numbers get even more stupid if we start to refuel starship to a  tanker that is fully fueled on a highly hell optical orbit, like getting a 500 ton probe to Jupiter orbit, or 200 tons to orbit one of it's moon, all done with only propulsive method.

 

Edited March 3 by Flavio hc16

[tater]

Buddy is sending me pics from Starbase—he's driving home from CDMX, so figured might as well go via Brownsville and Starbase.

Edited March 3 by tater

[CatastrophicFailure]

5 hours ago, Flavio hc16 said:

and there was a open letter by some people at NASA talking about using starship and that NASA need to start to dream big).

Came here to say this (linky no worky ) in reference to: 

10 hours ago, AckSed said:

If you'll allow me a little rant here, no-one is prepared for what's coming when both StarShip reuse and in-orbit refuelling is proven out. No-one. Not. A. Soul.

Largely I'd agree, but there ARE people entrenched within the bureaucracies who are, maybe even their superiors are, but everyone's had a bit too much "we've-been-here-before" over the decades about what's surely coming just over the next hill that never actually arrives (NASP anyone?). So they're afraid to seriously talk about it, as if even that much attention might make it all vanish like a dim star just in your periphery when you try to really see it, as so many have before. When Starship really and truly is here, the floodgates will open.

17 hours ago, StrandedonEarth said:

Someone would have to run the numbers, and it would be a delicate balance, for sure. A shorter trip would mean a much longer insertion burn, or more powerful (heavier) engines. Would it still have the dV for a shorter trip, with all that extra fuel/engine mass? Many trade-offs, to be sure. At least it wouldn't need as many RTGs, maybe.

IIRC an old UA-1205 Titan booster is around 250 tonnes. Expendable Starship can send 300 tonnes to just about anywhere. That's a whole lotta reliable, storable when-I-say-WHOAH-I-MEEEEEEEEEEEEEEAAAAAAN-WHOAH!!! once it gets there. With mass left.

Just sayin... 

[Exoscientist]

A counterintuitive result: partially reusable SuperHeavy/Starship can get same price per kilo as fully reusable one IF an expendable Starship can get 40 ton dry mass:

SpaceX should explore a weight-optimized, expendable Starship upper stage.
https://exoscientist.blogspot.com/2024/03/spacex-should-explore-weight-optimized.html

This is because of two reasons: 1.)a 40 ton expendable Starship compared to a 120 ton reusable one means you get 80 tons extra payload, and 2.)making the first stage reusable is more important because, like with the Falcon 9, the first stage makes up 2/3rds of the cost anyway.

cf.,

https://twitter.com/elonmusk/status/1111798912141017089

  Bob Clark

[tater]

Apparently WDR happening now

 

[Nuke]

19 hours ago, darthgently said:

I like Starship but it seems way overkill for a probe.  Maybe something like Zubrin's Mars Direct mini-starship, but autonomous, with the extra space devoted to more redundancy, sensors, and science?  Or maybe you mean the already planned probes launched as payload in Starship?

Anyway, here is a 2 year old vid of the Mars Direct concept with imagery of the mini Starship concept.  It is very Mars specific:

 

 

idk, i kind of like the shotgun approach to space exploration. why launch one deep space probe when you can fit 3 in the fairing.  there is also no rule that says superheavy can only be used with starship. a disposable 2-3 stage config, recovering the booster of course.

[tater]

 

[darthgently]

1 hour ago, Nuke said:

idk, i kind of like the shotgun approach to space exploration. why launch one deep space probe when you can fit 3 in the fairing.  there is also no rule that says superheavy can only be used with starship. a disposable 2-3 stage config, recovering the booster of course.

Absolutely!

[tater]

 

 

 

[tater]

Wallpaper alert, lol

 

 

 

 

[PakledHostage]

Do we have any credible rumors yet, w.r.t. a launch date? Space.com was anticipating a launch within 3 weeks, 2 weeks ago, so by their reckoning it should be in the next week or so?

[Spaceception]

I really like the look of these photos, it almost looks painted, and adds an amazing quality to it. 

2 minutes ago, PakledHostage said:

Do we have any credible rumors yet, w.r.t. a launch date? Space.com was anticipating a launch within 3 weeks, 2 weeks ago, so by their reckoning it should be in the next week or so?

Keep an eye on FTS installation. Once they do that, iirc, it puts them about a week give or take from us to see licenses/launch attempts.

Edited March 4 by Spaceception

[Minmus Taster]

1 minute ago, PakledHostage said:

Do we have any credible rumors yet, w.r.t. a launch date? Space.com was anticipating a launch within 3 weeks, 2 weeks ago, so by their reckoning it should be in the next week or so?

They need permission to launch from the FAA, could come tomorrow or in a month for all we know : P

[tater]

The IFT-1 mishap was closed Sept 8, license was Nov 15 after dealing with the 63 issues to work,  launch was Nov 18. 68 days for 63 issues. About 26 hours per issue.

IFT-2 mishap was closed Feb 26 with 17 issues. At the same 26hr/issue, that would be ~19 days. So the 16th for the license. Obviously the timing per issue could be different—and dealing with 63 action items likely makes the task slower, not faster (assuming some involve the same departments at Starbase, it might require them to be worked in serial rather than parallel. Could easily be next week.

 

[tater]

8 min

 

[tater]

 

[tater]

 

[tater]

4 min

 

 

[tater]

third routine flight to space in a day.