The space shuttle and the 747

[DSYoungEsq]

@Boyo_Jim

Yes, one might presume that. OTOH, one might be wrong.

@Stranger_On_A_Train

Enterprise was a protoflight glide test article; that is, it was built up to the anticipated specifications at the time that the schedule called for Approach and Landing Tests but the design evolved significantly. Although not equipped with main engines or a functional RCS (which would be of no use for ALT) it was ballasted to give the appropriate betas and flight dynamics. Although these changed somewhat for the final vehicles (and actually varies considerably between all of the vehicles, particularly the much heavier Columbia) this gave a baseline for an aerodynamic flight model to build the software that controls avionics.

Stranger

One might be wrong, but it turns out that this one isn’t.

[Sapo]

@Joe Frickin Friday

video on Wiki page was slow and small. Found better video at youtube. The money shot is at 0:27. The whole rig is already descending at the moment of separation; immediately afterward, they separate very rapidly, but it’s not clear whether this is because

A) the 747 is pushing into a steeper dive, or

B) the orbiter is mounted on the 747 at a high angle of attack (for these glide tests, but not for normal cross-country transport) so that’s producing a wretched excess of lift when the whole assembly is at cruise speed.

The first option seems unlikely, as the 747’s empennage might pitch up dangerously close to the orbiter. My guess is B). Note that normal cruise speed is reported by Wikipedia as 457 MPH, which is considerably faster than the shuttle’s landing speed; positioning the orbiter at a high AOA at these high speeds should generate a LOT of lift.

Amazing stuff. I was ignorant of this whole step. Cool. It does look more like B than A. I am no expert on any related field, but it doesn’t look like the 747 is diving.

[RedSwinglineOne]

@Xema

But the Shuttle uses a special microwave guidance system, and without this a precise touchdown is unlikely.

Are you sure? Unless the movie The Core is lying to me, the shuttle navigates with magnetic compasses. If you get off course, you whip out your NASA issued street map of the greater Los Angeles area, and plot a course for the L.A. River. You just have to land between the overpasses.

[not_alice]

Related question:

Back in the period between the Challenger explosion and the resumption of shuttle flights, the launch of the Hubble Space Telescope (possibly not yet renamed “Hubble”, just “Space Telescope” still), it seems to me as an employee of the (Hubble) Space Telescope Science Institute in Baltimore, that I recall NASA tossed us a morale bone and flew a shuttle on the back of a 747 over our offices, or at least close enough to see it from the parking lot. I also seem to recall that this was at spectacularly low altitude, possibly well under 1000 feet, right over the heart of Baltimore.

How low can this contraption actually fly safely? How does that differ from a 747 by itself?