NASA shuttle's landing

[toomuchradiations]

Hi,

is that true that the NASA shuttle only ever did autolands??....why was it preferred to a manual landing since the wx conditions for each one of its landings were way above cat 1??what if the autoapproach capability failed??...would the crew have been able to land it??
i would assume that the autoland was common practise only because its pilots never actually did any touch and goes on it as opposed to many automatic computer tested landings....

:confused: :confused: :confused: :confused:

[411A]

Yes, automatic approach/land ops are normal with the shuttle, however manual landings are used, and practiced for, in the sim.
Originally, before the shuttle sim was available, the first shuttle pilots used a DAL L10 sim at ATL, that had been specifically modified, for the steeper approaches.

And yes, the shuttle uses DLC, just like the Lockheed Trimotor does...quite successfully.

[toomuchradiations]

what's DLC?? and why did the shuttle have steeper approaches??i thought it had a normal 3 degree GP.....

why do they prefer the automatic app and landing more than the manual one?
thanks,
tmr

[411A]

DLC...Direct Lift Control, using wing spoiler panels to achieve accurate pitch attitude and descent rate, on the glidepath.

In addition, the shuttle has a rather steep descent path...can't remember offhand just how steep, but steep.
12 degrees rings a bell.

And as for automatic approach landings (oftentimes call 'autolands')...it's safer, and generally more accurate as well.

[Rainboe]

Shuttle approach glideslope (and it is gliding!) is about 22 degrees. Incredibly steep, and fast- it's a flying heavy brick with little delta wings. For the last few hundred feet it rounds out to bleed off speed so it transitions to a low level glideslope that is much shallower. I understood there was a lot of competition in the astronaut corps to land it on the nail at the right speed, so I think it is mainly landed manually. If i was a command pilot, I would hate to see the automatics doing my job!

[Wycombe]

Pretty sure they have a Gulfstream (G2 or 3 I think) that they use to practice the approaches - I think it's got a modified cockpit (at least on one side) to replicate the Shuttle controls to some extent.

Remember reading somewhere that the glide angle (until the latter stages where it goes shallower to bleed off speed) is something like 20 degrees :eek:

[Strepsils]

thought it had a normal 3 degree GP.....


If you can achieve that with no engines I think Boeing and Airbus would like to hear from you!:} ;)

[ORAC]

Shuttle re-entry and landing is divided into 3 stages, the first 2 under automatic control, the third manually flown by the pilot.

The first phase of descent is labeled simply Entry and extends from five minutes before the re-entry Interface until the start of TAEM.

Terminal Area Energy Management (TAEM) starts when the orbiter has decelerated to Manch 2.5 at about 83,000 feet until the shuttle reaches Mach 1 at about 10,000 feet.

The approach and landing phase extends from Mach 1 until touchdown. The pilot is presented with a heading alignment circle on his display which gives him command cues to fly a descending turn to intercept the glideslope at the correct height and speed and then glideslope cues. But its all manually flown....

The Russian Buran, on the other hand, was totally automatic. It didn´t even have a crew on its test flights.

[JackOffallTrades]

I thought the shuttle started its flare from several thousand feet? read 6000 somewhere...

More amusingly the gear is lowered by explosives!! 1 shot per gear leg! hence the gear is lowered by 3 push buttons instead of the usuall gear lever.

[eire757]

Most of you guys are pretty close to the mark on this one. I did discuss this with a NASA contract engineer once who wasn't involved with shuttle but was 'in the know'. Apparently it does shallow ROD at around 6kft but the flare itself is much closer to the ground. Not even astronauts could do a continuous flare from 6k! And yes it's very much flown manually albeit in a sort of flight director following way as described above. As for the explosives lowering the gear-my own laymans thoughts would be 1.lighter than hydraulics 2. More reliable than gravity/hydraulics (especially since you only have the one shot at a landing):eek:

[pigboat]

The aircraft they used to use was a Gulfstream II. The approach is flown from altitude with reverse thrust selected, to approximate the glide characteristics of the shuttle. :eek:

[False Capture]

Not quite true Jack,
When the landing gear is commanded down by the crew, the uplock hook for each gear is unlocked by hydraulic pressure. Once the hook is released , the gear is driven down and aft by springs, hydraulic actuators, aerodynamic forces and gravity. The doors freefall open when unlocked , sometimes aided by the wheels and tyres pushing on them. The landing gear reach the full-down and extended position within 10 seconds and are locked in position by spring-loaded downlock bungees. If hydraulic pressue is not available to release the the uplock, a pyrotechnic iniator at each landing gear uplock hook automatically releases the uplock hook on each gear one second after the crew has commanded the gear down. The landing gear is deployed at approx 300feet AGL.

[Rainboe]

I guess there is not a lot of worry that the landing gear doors are iced up!:)

[False Capture]

... and it's not like you'd be going around if they were iced up.;)

[Max Angle]

Landings are all manually flown but the autoland has been tested on a few missions I believe. Normal glideslope is about 20-22 degrees depending on weight and is maintained until around 1500ft agl when a flare to 3 degree "inner" glideslope is made to bleed off speed and arrest the huge rate of descent. 20 degrees equates to 7 miles out at 12,000ft so it's pretty steep, overhead the airfield at 40,000ft to touchdown is about 4 minutes.

[canyonblue737]

Some info for all of you...

1. There has NEVER been an autoland of a US Space Shuttle (the Soviet Buran's only flight was unpiloted so of course it did.)

2. The shuttle does have the capability to autoland in theory but people have to work the gear at a minimum so it isn't like the shuttle could be unmanned.

3. In the early shuttle program they were trying to test the autoland to ever lower altitudes before manual control was started and on STS-3 (the only landing at White Sands) the autoland took it down to about 50-100 feet but was way fast and off profile and because of it they had two problems, at the time they lowered gear based on speed not radar altimeter (which they since changed) and so the gear only was down and locked less than 2-3 seconds prior to touchdown which was dangerous and second the human controlled flare and touchdown was poor since they "took it" so late and off profile and later actual rerotated almost striking the tail. The whole incident caused a large scale review of landing procedures and there is a big 40-50 page blow by blow of the approach problems done up as a NASA study after the flight.

Here it is: http://spaceflightnow.com/shuttle/features/000414overhaul/sts03_qt.html

4. After the STS-3 problem they never again took it on auto so low and now in the modern shuttle program most commanders hand fly from 100,000 feet down including the entire HAC (heading alignment circle) and landing. Often Commanders will allow the Pilot (ie. the Co-pilot) to fly part of the HAC as a courtsey. It remains a commander preference where exactly they begin to fly it but 100k is the common number.

5. 22 degrees GP is common I think and a slight reduction in GP while on final at around 5-8k is normal, flare is far later while still a few hundred feet in the air.

[False Capture]

Wow, great video canyonblue737.:eek:

[canyonblue737]

Wow, great video canyonblue737.:eek:

clearly someone in the program would know the real answer but the sense i get as an outsider watching closely is after STS-3 and a few more less ambitious tests they kinda said, "well, let's just have 'em fly it and quit messing around with this system which while it "works" clearly isn't as good or safe as the guys up front just hand flying."

it seems however the autopilot does a great job of doing the S turns on the RCS jets during the initial entry interface so seldom if ever do the guys hand fly that. when columbia was lost it was on autopilot till it rolled out of control where the command went to manual and still couldn't recover it.

[ferrydude]

Yes, automatic approach/land ops are normal with the shuttle, however manual landings are used, and practiced for, in the sim.
Originally, before the shuttle sim was available, the first shuttle pilots used a DAL L10 sim at ATL, that had been specifically modified, for the steeper approaches.

And yes, the shuttle uses DLC, just like the Lockheed Trimotor does...quite successfully.

How about some verifiable sources for this nonsense???

[411A]

I would respectfully suggest you do an internet search, ferrydude, but failing that, I supplied a name at Lockheed for you before...whatsa matter, lost the quarter for the telephone?:hmm: :hmm:

[ferrydude]

Let's be clear . You've already been proven wrong on Shuttle Autolands.
Lockheed merely implemented DLC into the Tristar, it was actually developed and validated by NASA. Shuttle does NOT have direct lift control. The first steep approach and landing tests for the shuttle program were done in a Convair. No Shuttle pilots ever officially trained in any Delta sims.

[411A]

Sadly, ferrydude, you are severely misinformed about DLC and the use (officially) of the L10 sim for shuttle training in the very early days.
In fact, I know a couple of DAL guys who were in the sim and watched the whole exercise(s).

[ferrydude]

Please verify your memory with just one relevant internet link

[ferrydude]

umm yeah, I thought not

[Rainboe]

The only controls I am aware of the shuttle using apart from elevons and rudder is the split rudder speedbrake. Is this somehow coupled in to a DLC system? With the enormous drag the vehicle has, I'd have thought the rudder speedbrake was negligible.

[error_401]

Reposting.

Try starting your search from here. It's a great source.

Get the tech details here:

http://spaceflight.nasa.gov/shuttle/reference/index.html

and the landing here:

http://spaceflight.nasa.gov/shuttle/reference/basics/landing.html

always go to the source for information :cool:

[squawkident.]

wow only looked at the bottom link (landing) but still really interesting. Too true-im sure if anybody actually knows the landing procedures and parameters, its NASA themselves.