Virgin Galactic, Branson's space venture

[sh1pman]

53 minutes ago, tater said:

 

So this engine is supposed to be used with their Launcher One rocket, which is kinda like Falcon 1, but costs more and lifts less. How exactly is it going to pay off? 

[Bill Phil]

3 hours ago, sh1pman said:

So this engine is supposed to be used with their Launcher One rocket, which is kinda like Falcon 1, but costs more and lifts less. How exactly is it going to pay off? 

Smallsat launches, I suppose. Falcon 1 demonstrated 180 kg of payload, although it could have probably done more.

More generally: Can we all just take a moment and revel in the sheer number of orbital rockets in development and in use? This is certainly a slow period for manned spaceflight, but for unmanned? Holy snap!

[tater]

 

[sh1pman]

 

[Wjolcz]

On 4/24/2018 at 2:12 AM, sh1pman said:

So this engine is supposed to be used with their Launcher One rocket, which is kinda like Falcon 1, but costs more and lifts less. How exactly is it going to pay off? 

Wikipedia (not the best source, I know) says LauncherOne will have 200kg of LEO capability. Also, shouldn't solid boosters theoretically cost less since they are less complicated (they are, right?).

[tater]

 

[Brotoro]

And it did...what?

[Scotius]

Did not fall apart in flight Always a plus.

[wumpus]

34 minutes ago, Scotius said:

Did not fall apart in flight Always a plus.

How much different is it from Spaceship Two?  I assume it won't allow the wings to be stuck in the wrong position without a few overrides (unless the computers agree), and I'm sure they couldn't repair the old one, but anything else different?

[tater]

 

[mikegarrison]

I don't know why they ever bothered with all the complicated wing/tail/airbrakes/geometry. They are basically doing the same thing the X-15 did back in the 1960s, except with people in the back seat. The X-15 didn't need all those shape-changing wings.

[Wjolcz]

So I guess the answer to the question "What makes something look CGI?" is simple: stabilization. Shame I'm out of likes for today.

24 minutes ago, mikegarrison said:

I don't know why they ever bothered with all the complicated wing/tail/airbrakes/geometry. They are basically doing the same thing the X-15 did back in the 1960s, except with people in the back seat. The X-15 didn't need all those shape-changing wings.

They wouldn't bother with it if they didn't have a reason. IIRC X-15 and this are different. One was supposed to go very fast and sideways-ish (and heat up like crazy) and this one is supposed to quickly go up and then slow down while going down. AFAIK the feather wing design makes the flight time simply shorter. Scott Manley made a video explaining this.

 

Edited May 31, 2018 by Wjolcz

[Wjolcz]

@mikegarrison from Wikipedia:

In 2004, aircraft designer Burt Rutandemonstrated the feasibility of a shape-changing airfoil for reentry with the suborbital SpaceShipOne. The wings on this craft rotate upward into the feather configuration that provides a shuttlecock effect. Thus SpaceShipOne achieves much more aerodynamic drag on reentry while not experiencing significant thermal loads.

The configuration increases drag, as the craft is now less streamlined and results in more atmospheric gas particles hitting the spacecraft at higher altitudes than otherwise. The aircraft thus slows down more in higher atmospheric layers which is the key to efficient reentry. Secondly, the aircraft will automatically orient itself in this state to a high drag attitude.

So it's not at all like X-15. X-15 would have to not only have protective heat shielding but probably a completely different ascent profile too. If X-15 followed the same ascent profile as SpaceShip Two it would stall. If VG did it X-15 style the aircraft would be heavier (because of the shielding) and the flight would not only be more dangerous (speed, heat, stall) but also last longer as bleeding off the speed would take longer.

Edited May 31, 2018 by Wjolcz

[wumpus]

The X-15 was designed more for high speed tests (and flew many more flat tests than "parabolic space shots"), so all that shielding the X-15 had was necessary.  SpaceShipOne has no speed requirements (outside of delta-v) and doesn't require the shielding for direct mission requirements.  The shuttlecock shape allows it to reenter and still not worry about said shielding.

The planes had different design goals and were designed differently.  Imagine that!

[tater]

 

[Nibb31]

The shuttlecock design still seems like a lot of unnecessary complexity and introduces plenty of single point failures. I'm pretty sure a blunt body design and a fine layer of PICA-X would have been more than enough.

[YNM]

On shuttlecock :

There's also the question of G-loading. Virgin Galactic is taking civilians, not military. In military a clear risk of direct death is acceptable, and injuries are expectable. Not quite the case for civilians. So whatever they're doing, it's a lot about comfort and safety. Military can go freak all on those two, they care far more on security.

Edited June 5, 2018 by YNM

[Racescort666]

Something worth noting about the X-15, it was specifically intended to explore high airframe heating. From the Preliminary Outline Specification (Oct. 15, 1954):

Quote

For exploring the aerodynamic heating problem, the structure
must be subjected to extreme heating conditions. Allowable
skin temperatures are of the order of 1200° F and maximum
heating rates of the order of thirty (30) BTU/sq. ft/sec.
are desired. .i\.ltitude-speed requirements are also such that
radiation heat loss is of comparable magnitude to the convective
heat input with resultant skin temperatures well
below adiabatic boundary-layer temperature.

You probably don't want to do this with a composite skin aircraft like the Virgin Space Ships. Although there might be other entry profiles, the shuttlecock high drag, high stability entry profile is probably best choice for something like a space tourism air(space)craft.

[Nibb31]

But SpaceShipTwo doesn't go that fast. It only reaches Mach 2 (maybe Mach 3), which puts it in Concorde heating territory. We already have coating materials that can resist high Mach loads.

[sh1pman]

51 minutes ago, Nibb31 said:

But SpaceShipTwo doesn't go that fast. It only reaches Mach 2 (maybe Mach 3), which puts it in Concorde heating territory. We already have coating materials that can resist high Mach loads.

Mach 3.4, actually. Faster than SR-71, which was heated up to  300°C during the flight, and it had to use active cooling with fuel circulating under the airframe. It also had "leaky" fuselage with gaps between panels to deal with thermal expansion.

SS2 can't use this approach, obviously. 

Edited June 5, 2018 by sh1pman

[YNM]

5 hours ago, Nibb31 said:

It only reaches Mach 2 (maybe Mach 3), which puts it in Concorde heating territory.

Guess how it achieved that. (hint : trajectory and feathers.)

[sh1pman]

Interesting, they are considering rocket reusability at some point in the future.

[Xd the great]

On 6/20/2018 at 5:47 AM, sh1pman said:

Interesting, they are considering rocket reusability at some point in the future.

Meh, spaceX already does that. But it will be interesting to see how they will do it.

[sh1pman]

10 minutes ago, Xd the great said:

Meh, spaceX already does that

So? It’s good to see others recognizing the importance of reusability.

[Xd the great]

6 minutes ago, sh1pman said:

So? It’s good to see others recognizing the importance of reusability.

Everyone recognizes. Its just hard to do.