Vast, a Startup for "human habitation, first in LEO, and then beyond"

[Paul451]

Dog-piling...

I haven't been following closely, but something strikes me about this design:
You can't walk.
You have gravity, but you're confined to floors that are only a few meters across.

Whether >5m or <8m, that's not a tiny room. I'm currently in a 5x3.6m room and I can't exactly reach the other side without walking.

Ladders/stairs between floors is good for exercise.

If each module is either 3 or 5 floors (depending on whether you judge by the no. of windows or no. rings). Assuming worst-case 3. That's more floor-space than my flat. And there's another five modules like that. 18 large rooms.

Plus the low gravity hub.

[That said, 3 floors per module in 14+ metre modules (if TM is right) means ~4.7m between floors. Even if 0.7m (2ft) was underfloor storage/utilities, that's still 4m/13ft ceilings. (Which is definitely more than my flat.) Seems like overkill. You could easily fit five floors with a decent 8ft ceiling, still with underfloor storage/utilities. Even six floors, with 7ft ceilings, but starting to feel a bit "ship's cabin". But five floors would match the number of rings and makes sense to have the floors attached at a hard-point.]

The modules closer to the centre have lower gravity, the centre module includes zero-g. Hence...

And of course you can't float either.

In the central module you can. And the low-g pair next to the hub might not even bother having solid floors. Just a grid-deck and ladders. That's a 14m by 5 by 5m volume, with the ability to jump more than your own height and clamber around like a monkey wishes it could. Right next to the 14x5x5m hub which goes from lunar gravity to zero-g.

[Twark_Main]

[That said, 3 floors per module in 14+ metre modules (if TM is right) means ~4.7m between floors. Even if 0.7m (2ft) was underfloor storage/utilities, that's still 4m/13ft ceilings. (Which is definitely more than my flat.) Seems like overkill. You could easily fit five floors with a decent 8ft ceiling, still with underfloor storage/utilities. Even six floors, with 7ft ceilings, but starting to feel a bit "ship's cabin". But five floors would match the number of rings and makes sense to have the floors attached at a hard-point.]

Upon reflection you're completely right. Good powers of observation, thanks.

[Paul451]

Somebody should do an animation of the view from that seat while the station is spinning.  Vertigo much?

At, say, 4RPM, it's one rotation every 15 seconds. That's not a fast carousel.

It's 3 RPM, so once every 20 seconds.

50m radius (the figure you used) at 3RPM is 0.5g. Why that figure? (I was assuming 4RPM and ~1g at the bottom-most floor.)

Be sure to get out your ray-tracer, so you can model the nauseating motion of the non-axial sunbeams across the room.

I mean, I wouldn't like it, but how is it nauseating? Do you throw-up when cars drive past at night and moving headlights shine through your window?

Any interior rendering is just supposed to be "representative." That's all we should expect at this stage of R&D. No point in wasting valuable time and resources on detailed interior designs that are going to change anyway.

I'm not gonna read anything into the couch and cat and the little decorative shelves, they are obviously just standard elements in the artist's 3d modelling library, but surely at least the external windows should be a known quantity since they haven't changed much between the sketch and the render. Where else would the artist get the idea for two-round-windows in an inset if not from a misreading/misalignment/misscaling of the external layout?

(Another absence, no MMOD covers on the windows.)

Obviously the project is doomed, doomed!!!

Well, it will be if those windows get holed.

(If it's not, I'll say I've never seen an RCS system like that. When it was dots on the sketch, you could squint and imaging semi-hidden thrusters like on Dragon. But in the render, even that goes away.)

Many spacecraft have non-hidden RCS nozzles.

But none that look like remotely that.

(Plus they aren't in a useful location for RCS.)

So we're back to yelling at the poor artist for either terrible bolts or worse RCS.

[Twark_Main]

Somebody should do an animation of the view from that seat while the station is spinning.  Vertigo much?

At, say, 4RPM, it's one rotation every 15 seconds. That's not a fast carousel.

It's 3 RPM, so once every 20 seconds.

50m radius (the figure you used) at 3RPM is 0.5g. Why that figure? (I was assuming 4RPM and ~1g at the bottom-most floor.)

Bad math, ignore me.

Be sure to get out your ray-tracer, so you can model the nauseating motion of the non-axial sunbeams across the room.

I mean, I wouldn't like it, but how is it nauseating? Do you throw-up when cars drive past at night and moving headlights shine through your window?

If it was happening because my car was tumbling through the air continuously for many minutes/hours/days, I might.

Mismatched visual cues vs expectations are strongly related to vestibular motion sickness.

Any interior rendering is just supposed to be "representative." That's all we should expect at this stage of R&D. No point in wasting valuable time and resources on detailed interior designs that are going to change anyway.

I'm not gonna read anything into the couch and cat and the little decorative shelves, they are obviously just standard elements in the artist's 3d modelling library, but surely at least the external windows should be a known quantity since they haven't changed much between the sketch and the render. Where else would the artist get the idea for two-round-windows in an inset if not from a misreading/misalignment/misscaling of the external layout?

First people were saying that the rendering is just a stock image placeholder, don't think anything of it, don't read into it.

Now they're saying the rendering is the entire universe, and what other source could an artist conceivably be getting visual inspiration about a space station from??

How times change!


As previously noted, the window spacing is dramatically different. It's clearly showing a different station design, so trying to "reconcile" two renderings of two different stations will inevitably be misleading.

(Another absence, no MMOD covers on the windows.)

Obviously the project is doomed, doomed!!!

Well, it will be if those windows get holed.

Ok fine, we can do it your way.

[stating the obvious]

The real windows will have covers.

[/stating the obvious]

(If it's not, I'll say I've never seen an RCS system like that. When it was dots on the sketch, you could squint and imaging semi-hidden thrusters like on Dragon. But in the render, even that goes away.)

Many spacecraft have non-hidden RCS nozzles.

But none that look like remotely that.

Again you are being overconfident. We can't tell, at this resolution.

They could be RCS nozzles, or they could be something else.

(Plus they aren't in a useful location for RCS.)

Quite the contrary. "At the ends of the rod" and "at the ends of each module" and "in a place that won't get covered up when other modules are attached" is exactly where you would want the RCS.

So we're back to yelling at the poor artist for either terrible bolts or worse RCS.

RCS would be the right size at least, but "bolts" are very wrong. You even acknowledge how silly such bolts would be, but strangely you still choose to blame the artist instead of critiquing your own absurd interpretation.

"Doctor, it hurts when I do this!"

[JohnFornaro]

As I mentioned up thread; one can imagine the shopped model and cat to be sitting on the "floor".   one should zoom into the yoga mat table shown in the baton.  One would have to ignore that the windows are one to a module, and would be stacked vertically in any case.  One would also have to assume that the curved walls of the module have been squared off, so the pic would be accurate.

If nothing else, the communication skills between the engineering team and the artist are lacking.  We're not seeing competence being demonstrated.   There's an argument to be made that they merely shopped a "Vast" t-shirt on a stock image.

[I made the sketch in August, and modified it this morning.]

[lamontagne]

The little elements near the windows really look a lot like thrusters.
There is significant thickness added to the outer hull, and openings? in that thickness.

[meekGee]

Not overlooking it, just noting something.

In a regular space station, you can float.  I haven't tried it myself, but it looks like it makes everything roomier.  You can go in a straight line that is certainly more than 5 m long.

Here, you have gravity again, so you are confined to a floor.  5 m or so (OD, mind you, so subtract walls, insulation, wall-mounted storage or cubbies) is still pretty small.  Yes I've been in 5 m rooms.  They're certainly larger than 4 m rooms, and a bit smaller than 6 m rooms.

The idea here is to create an environment where people can do well, not just survive, and I think this is an impediment.

You could do the same things with two types of modules: long 5 m OD tubes, and shorter 8.5 m disks.

Commonality is important, but so is their goal of making a habitat that's more than just a survivable experience.

This objection is neverending.

If the modules were 8.5 meters diameter, someone would immediately complain they there are no large open expanses of parkland and forests. I've seen it happen.


This is exactly what makes people say "perfect is the enemy of good."


The only way to maintain sanity and avoid endless scope creep is to focus on real mission requirements and ignore the "wouldn't it be nice if..." treadmill.

Whoever said anything against "good enough"?

Minimum viable product is perfectly fine.

Doesn't mean we can't discuss some basic fundamental differences between zero g and 1-g designs.

Also "bigger is always better" is a red herring.  8.5 is simply the other constraining dimension when using starship, that's all.

These folks are at a super-early phase.  If you can't talk about trade-offs now, then when?

Adding:
Vast is aiming at a very livable environment, one where people can thrive in for extended periods of time.

Once you introduce gravity, while you gain a lot of comfort, you lose the ability to float down the length of the tube.   That's a major hit, and it makes the other dimension (the diameter) more important than it is for a zero-g tube.

There's nothing prohibitively complex about an 8.5 m short module.  Clearly it's less optimized, development wise, than having all modules being identical, but that's obvious - I'm not contesting that.

Their design right now is about as mature as MCT was when tfirst introduced. Maybe even less so.

Talking about trade-offs now is the right thing to do, whether y'all dog-pile or not...

[JohnFornaro]

Once you introduce gravity, while you gain a lot of comfort, you lose the ability to float down the length of the tube.   That's a major hit...

From:

https://www.nasa.gov/feature/ames/mitochondria-cell-science

Mitochondrial Changes Key to Health Problems in Space

Talking about trade-offs now is the right thing to do...

What trade-offs?

[meekGee]

Once you introduce gravity, while you gain a lot of comfort, you lose the ability to float down the length of the tube.   That's a major hit...

From:

https://www.nasa.gov/feature/ames/mitochondria-cell-science

Mitochondrial Changes Key to Health Problems in Space

Talking about trade-offs now is the right thing to do...

What trade-offs?

They're using Starship to launch.

In the current concept, they chose to go with all identical modules, and they are 5 m in diameter, among other things to make them as long as possible.

One possible option is to have a bone-like shape, with high g modules being shorter and wider. (Starship can maybe allow 8.5 m?)  So you'll have two types of modules.

I'm not even saying which is better, just noting that once you can't float around the station, it'll feel a lot smaller than the same enclosure in zero g.

Then everyone got upset.

[Steven Pietrobon]

Here's an enhanced version of the new image, which shows the bottom solar panels a bit clearer.

[lamontagne]

Here's an enhanced version of the new image, which shows the bottom solar panels a bit clearer.

Let's not forget that most rendering software is designed for the surface of the Earth, so the shadows are probably random since the sun often 'turns off' at seven in the morning, before you hit the horizon.  The artist would need to have specific instructions on shadows to actually render then realistically.

[Vultur]

Yeah, the "zero-g gives you more usable room" thing is my biggest issue with artificial gravity. Artificial gravity will probably feel more closed-in than the same size space in zero-g.

[Asteroza]

Yeah, the "zero-g gives you more usable room" thing is my biggest issue with artificial gravity. Artificial gravity will probably feel more closed-in than the same size space in zero-g.

Yes and no, I think? If the artificial gravity is low, then it makes for a very accessible warren of spaces. Remember treehouses and cardboard forts? Part of their charm is that low mass as a child makes accessing higher spaces comparatively easy. You sort of get that as an adult in a low gravity space. Instead of a long straight vertical tunnel with spaces branching off, perhaps something more akin to a prairie dog nest or anthill?

[Cheapchips]

Successful hot fire of Vast's first development hardware, a 150 Newton Gaseous Methane / Gaseous Ox Thruster!
Our team went from concept to 3D printed Inconel thruster in just a few months. This test will help us learn the right film cooling ratios for our flight designs.

https://twitter.com/vast/status/1593758991946899456?t=GzuSG5WeFG8HGjbjJbRvDQ&s=19

[Twark_Main]

The use of methagox is an interesting choice. With SpaceX's plans, it can be presumed to have high availability.

150 newtons (yes that's right, no capital letter, for shame Vast!  ) is within band for RCS thrusters. Apollo RCS was 445 N and Dragon's Draco puts out 400 N.


Assuming 300 seconds Isp and 300 tonnes total station mass, gyroscopically precessing the station around once per year (for PV, thermal, and comfortable illumination) will burn 5 tonnes per year.

If we assume a 1 second nominal burn time, that's a thruster firing every 6 minutes, or 88,000 cycles per year (half that if you alternate between thrusters at both ends).

With correctly designed software controls, these thruster firings can also provide up to 45 m/s annually in "free" drag reboost.

[HMXHMX]

The use of methagox is an interesting choice. With SpaceX's plans, it can be presumed to have high availability.

150 newtons (yes that's right, no capital letter, for shame Vast!  ) is within band for RCS thrusters. Apollo RCS was 445 N and Dragon's Draco puts out 400 N.


Assuming 300 seconds Isp and 300 tonnes total station mass, gyroscopically precessing the station around once per year (for PV, thermal, and comfortable illumination) will burn 5 tonnes per year.

If we assume a 1 second nominal burn time, that's a thruster firing every 6 minutes, or 88,000 cycles per year (half that if you alternate between thrusters at both ends).

With correctly designed software controls, these thruster firings can also provide up to 45 m/s annually in "free" drag reboost.

Yes, I like GOX-CNG propellants for this sort of application.  At t/Space in 2005 we developed a 440 N (100-lbf) thruster using the same propellants.

[rsdavis9]

The use of methagox is an interesting choice. With SpaceX's plans, it can be presumed to have high availability.

150 newtons (yes that's right, no capital letter, for shame Vast!  ) is within band for RCS thrusters. Apollo RCS was 445 N and Dragon's Draco puts out 400 N.


Assuming 300 seconds Isp and 300 tonnes total station mass, gyroscopically precessing the station around once per year (for PV, thermal, and comfortable illumination) will burn 5 tonnes per year.

If we assume a 1 second nominal burn time, that's a thruster firing every 6 minutes, or 88,000 cycles per year (half that if you alternate between thrusters at both ends).

With correctly designed software controls, these thruster firings can also provide up to 45 m/s annually in "free" drag reboost.

Yes, I like GOX-CNG propellants for this sort of application.  At t/Space in 2005 we developed a 440 N (100-lbf) thruster using the same propellants.

Do you know/remember what the chamber pressure was for this thruster?
Sort of interesting from the point of view of what gases/pressures are available on starship.

[HMXHMX]

The use of methagox is an interesting choice. With SpaceX's plans, it can be presumed to have high availability.

150 newtons (yes that's right, no capital letter, for shame Vast!  ) is within band for RCS thrusters. Apollo RCS was 445 N and Dragon's Draco puts out 400 N.


Assuming 300 seconds Isp and 300 tonnes total station mass, gyroscopically precessing the station around once per year (for PV, thermal, and comfortable illumination) will burn 5 tonnes per year.

If we assume a 1 second nominal burn time, that's a thruster firing every 6 minutes, or 88,000 cycles per year (half that if you alternate between thrusters at both ends).

With correctly designed software controls, these thruster firings can also provide up to 45 m/s annually in "free" drag reboost.

Yes, I like GOX-CNG propellants for this sort of application.  At t/Space in 2005 we developed a 440 N (100-lbf) thruster using the same propellants.

Do you know/remember what the chamber pressure was for this thruster?
Sort of interesting from the point of view of what gases/pressures are available on starship.

Design Pc was 100 psia.

[Paul451]

Assuming 300 seconds Isp and 300 tonnes total station mass, gyroscopically precessing the station around once per year (for PV, thermal, and comfortable illumination) will burn 5 tonnes per year.

(Coastal Ron reminded me of this subject in the Realistic Rotating thread, where he made a similar mistake.)

Note that you are adding a constant (ish) torque to induce a non-accelerating rotational velocity?

Once you induce the secondary rotation (rotation of the axis), conservation of angular momentum means it remains constant. Once and done. (Barring outside forces, moving masses, the usual complications.) There's no reason to keep applying torque.

[meekGee]

Assuming 300 seconds Isp and 300 tonnes total station mass, gyroscopically precessing the station around once per year (for PV, thermal, and comfortable illumination) will burn 5 tonnes per year.

(Coastal Ron reminded me of this subject in the Realistic Rotating thread, where he made a similar mistake.)

Note that you are adding a constant (ish) torque to induce a non-accelerating rotational velocity?

Once you induce the secondary rotation (rotation of the axis), conservation of angular momentum means it remains constant. Once and done. (Barring outside forces, moving masses, the usual complications.) There's no reason to keep applying torque.

Are you sure about that?  Planets don't work that way, right?  Where's the difference?