Virgin Galatic Spaceship Two down in the Mojave.

[pchapman]

Just for reference, to wrap one's head around how a vehicle like SS2 might work, here's info on Space Ship ONE. I don't know what systems and methods may have changed when scaling up to Space Ship Two -- with so much more mass to deal with. Info is from "Space Ship One - An Illustrated History", a ~2011 book by Dan Linehan.


Drop at 47,000'
Speed ??
C of G is aft with full fuel
3-4 G accel with rocket
Pull up to avoid overspeeding, Vne about 260 kts EAS.

[As an example, 250 kts EAS at 45,000' is almost exactly Mach 1.0]

Use electric trims after 8-9 seconds of burn due to high stick pressures (slow control by trims only)
Back to control stick once in very low density atmosphere
Maximum it achieved at engine shutdown was Mach 3.1 at 213,000 ft after 84 sec burn.
[That gives only 22 kts EAS - using a calculator on aerospaceweb. Many online calculators don't model the desired altitudes]

Apogee at about 3 min after engine start, 328,000 ft plus at best.
3.5 min weightless
Reaction Control System (pneumatic) at high altitude

Feathering done shortly before apogee. (Do it early in case of issues to deal with)

Feathering has redundant locks.
Feathering takes 13-14 seconds [A video for a prior SS2 flight shows much more rapid movement]
Feathering is by pneumatics, dual redundant interconnected systems.
Feather when under 10 knots EAS. [Low!]

Fastest speed reached (going down) was Mach 3.25, below 160 kts EAS.
5.5 G max on reentry (above 5 for 10 sec)
Max air temp ~ 1200F but with low density, heating rate is low.
(Heat resistant coating on nose and wings needed for boost phase only, not reentry but provides added margin).

Terminal velocity when feathered, if at low altitude, would be about 60 kts with its low wing loading of 12 ft/lb^2.

Un-feather once subsonic and below 1.2g on reentry.


As for SS2 planning to feather at M1.4, what kind of EAS might we be talking about?
If achieved at 100,000 ft, it would be 97 kts EAS.
If achieved at 200,000 ft, it would be 12 kts EAS.
The altitude certainly matters...

Edit:
Another bit of background as to prior achievements, and speeds and altitudes: The January 2014 flight achieved the following in an online article:

The SS2 rocket engine fired for 20 seconds, pushing the suborbital spacecraft to an altitude of 71,000 ft (18 km) and a top speed over Mach 1.4, both of which were new records for SS2. The Reaction Control System, feather re-entry system, and a thermal protection coating were successfully tested during the flight.

Not sure what that implies for feathering -- under 71k and Mach 1.4 would have a high EAS. If the numbers are right, one would expect feathering at a much lower Mach number.