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22 minutes ago, Dale Christopher said:

The year is 2019, SpaceX fans have started descending into mania due to no starship updates for a week or two.

TBH, I'm not really a SpaceX fan. I actually work for a sort of competing company. But you know, rockets and sh%t.

Anyway, that SMBC comic came out today. I have no doubt that Zach was inspired to draw it based on watching Elon's love letter to Mars a week ago, though.

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18 minutes ago, mikegarrison said:

TBH, I'm not really a SpaceX fan. I actually work for a sort of competing company. But you know, rockets and sh%t.

I'm literally a fan of anyone actually moving the ball down the field at this point. I have been space obsessed since, well, the Apollo era, with a Woolworth's plastic rocket on my little kid birthday cake (that was the extent of "theme" birthdays, back in the day, kids, our moms would put army men, or airplanes, etc on top of the cake---done.). I followed Shuttle pretty closely. I was involved with some space conferences, met a bunch of astronauts... and everything was constantly 20 years in the future. The same things, in fact were 20 years in the future. 1985, cool space future just after the turn of the century in 20 years! Mid 90s? Cool space stuff (same as '85) coming in... 20 years.

Before SpaceX started attempting landings, my hope was actually on Blue. I knew they were secretive, but kept expecting them to announce some launch, then see a Moon rocket roll towards a pad someplace. SpaceX moves faster, which I love.

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9 minutes ago, tater said:

SpaceX moves faster, which I love.

Somewhere, in an interview Elon stated after the abortive "greenhouse on mars idea" he resolved to figure out how to make his own rocket, and one of the things he mentioned was reading all the books he could find that had been written by the original old geezers that pioneered it all.

I'd like to see that entire reading list.

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14 minutes ago, tater said:

I'm literally a fan of anyone actually moving the ball down the field at this point. I have been space obsessed since, well, the Apollo era, with a Woolworth's plastic rocket on my little kid birthday cake (that was the extent of "theme" birthdays, back in the day, kids, our moms would put army men, or airplanes, etc on top of the cake---done.).

I feel more like that w.r.t. airplanes, which is probably why I studied what I studied and I work where I work. But space stuff is cool too.

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42 minutes ago, tater said:

I'm literally a fan of anyone actually moving the ball down the field at this point. I have been space obsessed since, well, the Apollo era, with a Woolworth's plastic rocket on my little kid birthday cake (that was the extent of "theme" birthdays, back in the day, kids, our moms would put army men, or airplanes, etc on top of the cake---done.)

I’m similarly space-obsessed, with a side obsession of MOAR POWAH! which covers practically anything that burns guzzles fuel (I got the astronaut figures on my kid cake one year). 

After seeing so many false starts and abandoned concepts over the years, it was easy to get pessimistic about the future of spaceflight. There was only the Shuttle (marvellous but ill-conceived machine that it was) to provide anything really interesting in space, and then was only Soyuz. It’s exciting to see someone finally leading the charge with game-changing techniques, and actually getting stuff built in an efficient, cost-effective manner. 

So yeah, I’m  a SpaceX fan, but it’s not like I think they’re gods or anything. I’m also a fan of BO and VG, and it’ll be nice to see those two light it up more. I’m NOT a fan of Antares. Solids and foreign engines, like really?:confused:

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Ever since Elon's interview with Everyday Astronaut, I've been kicking around the utility of employing some kind of altitude-compensated Raptor...not for Starship, per se, but for something smaller. Elon claims Starship will cost on the order of $2-3M per launch, which I think is rather extraordinarily low, but even at $20M (twice his highest estimate) it's still game-changing. Yet presumably there will be many instances where you simply do not need 100 tonne or fifty people delivered to, say, the ISS.

If Falcon 1 was the original Tesla Roadster, Falcon 9 is the Model S, and Falcon Heavy is the Model X, then Starship is clearly the Tesla semi-truck. But no one wants to drive to dinner in a tractor-trailer. Like Tesla, SpaceX needs a newer, better Roadster.

I decided to play with a Raptor-based SSTO using GNOM-style air-augmentation and altitude compensation, with the dedicated goal of developing a vehicle with the same capacity as Falcon 9+Dragon 2. With a fixed vacuum-sized nozzle integral with an inlet duct, the Raptor would have air-augmented altitude compensation as well as full expansion in vacuum, without the pain and suffering of an aerospike. I went with a single-engine design.

I assumed:

  • T/W ratio at liftoff: 1.2 (low because air augmentation will boost T/W ratio rapidly once moving)
  • Average air augmentation after liftoff (Mach 0 to Mach 1.75): 18%
  • Average air augmentation during boost (Mach 1.75 to Mach 5.5): 100%
  • Average air augmentation during supercruise (Mach 5.5 to Mach 12): 36%
  • Structural load multiplier (essentially, decreased skin thickness): 50%

Using the above assumptions and the application of the square-cube law, I came up with a single-Raptor vehicle massing 201 tonnes at launch, with a structural mass of 8.9 tonnes and 181 tonnes of methalox, and 10.8 tonnes of payload margin. 9,939 m/s total dV. Definitely enough to get to LEO and back with a crew of six.

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13 minutes ago, sevenperforce said:

structural mass of 8.9 tonnes

That’s a very optimistic dry mass. Less than half of that of an F9 S1. If it’s a reusable vehicle (I assume it is), then it will need a decent heat shield, landing legs, fins, etc. What’s it made of?

Edited by sh1pman
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10 minutes ago, sh1pman said:

That’s a very optimistic dry mass. Less than half of that of an F9 S1. If it’s a reusable vehicle (I assume it is), then it will need a decent heat shield, landing legs, fins, etc. What’s it made of?

It's less than half the length of a F9 first stage, so yep, that's the plan.

The square-cube application assumes that wet mass is dependent on volume, which scales with the cube of height, while dry mass is dependent on surface area, which scales with the square of height. Starship has a structural fraction of 3.4% of its GLOW (3520 tonnes). A 201-tonne vehicle has 6.7% the mass of Starship, so we assume 6.7% of the volume, 14.8% of the surface area, and 38.5% of the length. If this vehicle had the same skin thickness as Starship, it would have a dry mass of 17.8 tonnes, but its structural loading is only 6.7% as high, so we should reduce skin thickness. Doing so by 50% gives us a dry mass of 8.9 tonnes.

So yeah -- build it out of 301 stainless. Only do two fins (in the front), which saves some weight, and have them double as forward landing legs. Use methagox thrusters for auxiliary attitude control during entry as well as dual-thrust-axis landing.

 

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Only if something goes... south :lol: No, seriously, with reuseable booster risk is minimal. And second stage will not deorbit anywhere close Cuba (or other inhabitated areas). Plenty of open area in Atlantic and Pacific.

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2 hours ago, CatastrophicFailure said:

Interesting...

 

Like the guy said, should Cuban cows be nervous?

Wonder if it's because fairing catching is now a possible operational thing from FL (both catchers ready to roll).

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57 minutes ago, CatastrophicFailure said:

Curiouser and curiouser...

Good news for South Texas

2 hours ago, CatastrophicFailure said:

Interesting...

...bad news for Vandenberg.

No seriously, with JRTI and both fairing catchers away from the west coast and launches shifting towards the Cape... do they plan on launching anything else out of Vandenberg at all? Are they trying to phase it out? Just a bit of worried speculation there, that's all- it was always great to see everyone in the LA area go crazy about UFO's whenever a launch happened at the right time.

 

Hopefully this will look sufficiently different from normal launches that people in Miami will freak out too. It is Florida, after all.

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8 minutes ago, tater said:

Wonder if it's because fairing catching is now a possible operational thing from FL (both catchers ready to roll).

I'm amazed it's even a thing at all. Cuba seems awfully close by to go lobbing missiles over, and then there's Central America further downrange...

2 minutes ago, ThatGuyWithALongUsername said:

No seriously, with JRTI and both fairing catchers away from the west coast and launches shifting towards the Cape... do they plan on launching anything else out of Vandenberg at all? Are they trying to phase it out? Just a bit of worried speculation there, that's all- it was always great to see everyone in the LA area go crazy about UFO's whenever a launch happened at the right time.

I think there's one planned outta there late this year/early next, and then nothing else until late next year. Maybe Rocket Lab has gobbled up all the SSO payloads?

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13 minutes ago, CatastrophicFailure said:

I think there's one planned outta there late this year/early next, and then nothing else until late next year. Maybe Rocket Lab has gobbled up all the SSO payloads?

SpaceX will be doing monthly launches to SSO for their rideshare program, won't those be from Vandy?

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5 minutes ago, CatastrophicFailure said:

I think there's one planned outta there late this year/early next, and then nothing else until late next year. Maybe Rocket Lab has gobbled up all the SSO payloads?

That one that was "late this year/early next" was SAOCOM 1B I think, before this change...

They still have those SSO rideshare missions... but the launch days aren't really clear, and maybe those could be out of the cape now, too?

Also, yes, SSO, not just a regular polar orbit. Apparently, SAOCOM 1B is SSO, so SSO from the Cape is definitely possible, not just regular polar orbits. Can't seem to find any other info on that though? Is there just an inclination change or something?

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