SpaceX Tuesday...

[loudlashadjuster]

djdest said:

If you had no gimbals you wouldn't have a gyroscope!
You know what a gyroscope is made of?

Well, yes, traditional gyros use gimbals but I was inferring that mounting one inside another gimbal would kinda defeat the purpose. Not all gyroscopes use gimbals though, there are many solid state and optical types.

I doubt it's the gyros that are the problem though, after all the rockets themselves obviously have extremely good gyros, as will pretty much every 'normal' payload.

I'd imagine having to design the spooks' extreme cutting edge instruments to absorb severe loads in one plane to survive launch is enough of a hassle without worrying bracing for shocks in other orientations.

[MartG]

loudlashadjuster said:

I'd imagine having to design the spooks' extreme cutting edge instruments to absorb severe loads in one plane to survive launch is enough of a hassle without worrying bracing for shocks in other orientations.

It could simply be that the payload is relatively long but thin, so horizontal integration would place unacceptable bending loads on it, especially at its attachment point to the launcher

[shalmaneser]

MartG said:

loudlashadjuster said:

I'd imagine having to design the spooks' extreme cutting edge instruments to absorb severe loads in one plane to survive launch is enough of a hassle without worrying bracing for shocks in other orientations.

It could simply be that the payload is relatively long but thin, so horizontal integration would place unacceptable bending loads on it, especially at its attachment point to the launcher

Exactly. They're designed for stress in one axis ('down') while launching, it must be massive pain to also design for perpendicular stresses when horizontally integrated.

[MartG]

shalmaneser said:

MartG said:

loudlashadjuster said:

I'd imagine having to design the spooks' extreme cutting edge instruments to absorb severe loads in one plane to survive launch is enough of a hassle without worrying bracing for shocks in other orientations.

It could simply be that the payload is relatively long but thin, so horizontal integration would place unacceptable bending loads on it, especially at its attachment point to the launcher

Exactly. They're designed for stress in one axis ('down') while launching, it must be massive pain to also design for perpendicular stresses when horizontally integrated.

Yes - doing that must lead to extra structural weight if the payload is relatively long

[Eric Mc]

Quite a few launches today carry multiple payloads so the requirements for different customers need to be met on the same rocket.

[MartG]

If it is a structural issue then SpaceX could simply install temporary supports inside the fairing which are removed once it is vertical.

However if it is something else within the payload e.g. a sensitive optical system , then fitting the payload once the launcher is vertical at the pad would seem the simplest & cheapest way forward

[loudlashadjuster]

MartG said:

If it is a structural issue then SpaceX could simply install temporary supports inside the fairing which are removed once it is vertical.

However if it is something else within the payload e.g. a sensitive optical system , then fitting the payload once the launcher is vertical at the pad would seem the simplest & cheapest way forward

Doubt that would be either simple or cheap. The satellites are built and loaded in some degree of clean room conditions, can't imagine it would be trivial maintaining these transporting it to the pad, up a 70 m platform and into the vehicle.

[MartG]

loudlashadjuster said:

MartG said:

If it is a structural issue then SpaceX could simply install temporary supports inside the fairing which are removed once it is vertical.

However if it is something else within the payload e.g. a sensitive optical system , then fitting the payload once the launcher is vertical at the pad would seem the simplest & cheapest way forward

Doubt that would be either simple or cheap. The satellites are built and loaded in some degree of clean room conditions, can't imagine it would be trivial maintaining these transporting it to the pad, up a 70 m platform and into the vehicle.

The payload could be fitted to the launcher adapter and encapsulated in the fairing in a clean room before transportation to the pad. It is then simply(!) a case of bolting the adapter to the top of the launcher once it has been lifted into place. A very similar process to that already done for Atlas V, just taking place at the pad instead of in the vertical integration building

[annodomini2]

MartG said:

If it is a structural issue then SpaceX could simply install temporary supports inside the fairing which are removed once it is vertical.

However if it is something else within the payload e.g. a sensitive optical system , then fitting the payload once the launcher is vertical at the pad would seem the simplest & cheapest way forward

Optical system would be my guess as well, large complex mirrors and lenses, especially where NRO is concerned.

They had 3" resolution in the '60s, who knows what it is now.

[CraigyMc]

annodomini2 said:

MartG said:

If it is a structural issue then SpaceX could simply install temporary supports inside the fairing which are removed once it is vertical.

However if it is something else within the payload e.g. a sensitive optical system , then fitting the payload once the launcher is vertical at the pad would seem the simplest & cheapest way forward

Optical system would be my guess as well, large complex mirrors and lenses, especially where NRO is concerned.

They had 3" resolution in the '60s, who knows what it is now.

NASA were given a pair of telescopes by the NRO, both of which are better than the "fixed" Hubble. They have no mission funding to launch those so they are in storage, somewhere.

You have to question what the NRO have in active service if those are already outmoded.

ETA, sounds like a made-up story. Read here. https://www.popsci.com/technology/article/2012-06/...

[Eric Mc]

loudlashadjuster said:

MartG said:

If it is a structural issue then SpaceX could simply install temporary supports inside the fairing which are removed once it is vertical.

However if it is something else within the payload e.g. a sensitive optical system , then fitting the payload once the launcher is vertical at the pad would seem the simplest & cheapest way forward

Doubt that would be either simple or cheap. The satellites are built and loaded in some degree of clean room conditions, can't imagine it would be trivial maintaining these transporting it to the pad, up a 70 m platform and into the vehicle.

Many payloads are loaded onto the rocket at the pad. For decades it has been possible to surround the top of a rocket in "clean room conditions". In fact, the huge "Payload Structure" that was part of Pads 39A and 329B during the Shuttle era were precisely that, clean rooms which allowed work to be carried out on Shuttle payloads whilst the vehicle was sitting on the pad.

In the image below you can see that the structure has been swung back into the "stored" position in readiness for launch.



The next pictures shows the structure closed over the Shuttle. It was enormous.

[MartG]

Trying again - live in about 35 mins https://www.youtube.com/watch?v=-p-PToD2URA

[loudlashadjuster]

Eric Mc said:

Many payloads are loaded onto the rocket at the pad. For decades it has been possible to surround the top of a rocket in "clean room conditions". In fact, the huge "Payload Structure" that was part of Pads 39A and 329B during the Shuttle era were precisely that, clean rooms which allowed work to be carried out on Shuttle payloads whilst the vehicle was sitting on the pad.

In the image below you can see that the structure has been swung back into the "stored" position in readiness for launch.

The next pictures shows the structure closed over the Shuttle. It was enormous.

Yes, eminently possible, but I think those photos demonstrate it wouldn't be very cheap to adapt for Falcon (of one type, never mind two), nor would it seem to provide the lowest ongoing costs which is pretty much what SpaceX is all about.

Presumably the USAF money aimed at the use of the VAB?

[Eric Mc]

loudlashadjuster said:

Yes, eminently possible, but I think those photos demonstrate it wouldn't be very cheap to adapt for Falcon (of one type, never mind two), nor would it seem to provide the lowest ongoing costs which is pretty much what SpaceX is all about.

Presumably the USAF money aimed at the use of the VAB?

The USAF had no involvement in the construction of the VAB nort have they any involvement with SLS either. They were obviously heavilly involved in the Shuttle programme (until the Challenger accident) so they probably had some requirements that need the VAB to be amended to suit their needs during the Shuttle programme.

[anonymous-user]

Looking good. It's a sign of just how good SpaceX are at this stuff now that I'm disappointed not to be able to watch a Stage 1 landing today.

[MartG]

loudlashadjuster said:

Presumably the USAF money aimed at the use of the VAB?

SpaceX couldn't use Pad 39A for a vehicle erected in the VAB as their horizontal integration building blocks the old crawlerway between the pad and the VAB. LC40 is not accessible from the VAB.

If they were to follow the NASA model of VAB and mobile launcher carrying a vertical launcher, all three current facilities ( 2 in Florida, one at Vandenberg ) would require a new VAB to be built, and a new mobile launcher to be developed and built - the one for 39A would need to be able to keep the payload vertical while ascending the slope to the pad.

Much simpler & cheaper to continue moving the launcher to the pad horizontally, then fitting the payload once the vehicle is vertical.

[Atomic12C]

Watched the launch earlier - near the end of second engine cut off there was a growing leak of gas/liquid near the base of the thruster cone where it attaches to stage 2. Anyone else expecting the screens to suddenly go blank?

[Eric Mc]

That's pretty normal from what I recall of Falcon upper stages. I think it's not so much a leak as gas venting from an outflow pipe - possible exhaust from a pump or coolant loop.

[CraigyMc]

Atomic12C said:

Watched the launch earlier - near the end of second engine cut off there was a growing leak of gas/liquid near the base of the thruster cone where it attaches to stage 2. Anyone else expecting the screens to suddenly go blank?

I watched it too, but I thought that was just a boiloff valve.

[Kccv23highliftcam]

I'm sure they used to get a build up of ice at that vent in early launches....