Space Shuttle Launch Pad 39A with Challenger STS-6

[roma847]

Thanks Kirk for the very impressive video, 

whereby especially the first sequences

 

 

remind me of my very intensive work with lots of crazy details  while scratching the SSWS pipes, a longer time ago ... 

 

[xffw45343tg]

I remember a miniature launch pad like that. Some very talented chap was building one a long, long time ago - but then became distracted with a launch tower.

Oh wait...

 

 

[roma847]

Right Kirk, I can still remember that too,  this must have been then a total crazy guy, right? 

[Mustermark]

Crazy in a good way ❤️

[roma847]

Thanks Mark, 

a little bit of fun is always good. 

[roma847]

Hello everybody,

 

well, the same (art)break as every year, and the longer it lasts, the harder it is to get back in ...  

 

But nevertheless it should go on, and that's why: Go right ahead!

 

For the masking of the connection areas of the ET Attachments before the Flour process, one interface is still missing, and that is the one between the ET Vertical Struts and the SRB Aft Attach Struts, 

 

Source: forum.nasaspaceflight.com (Jester)

 

which were unfortunately not taken into account in both the Airfix Kit and Newware Kit, which results in this gap, which of course should not exist there.   

 

 

Via the local cable connections running in the Cable tray and through the Upper Strut, u.a. the ignition of the SRB Separation Motors took place, which initiated the separation from the ET after the burnout of the Boosters.

 

As one can see from the following image, the round cladding of the Upper Strut cannot be overlooked, 

 

Source: forum.nasaspaceflight.com (woods170)

 

and is not nearly just a puny thing like at the dainty Airfix Strut,

 

 

which can also be seen in this photo by Steve Patlan, 

 

Source: live.staticflickr.com (Steve Patlan)

 

who was close to the action at the time and has great photos in his albums.   

 

Source: live.staticflickr.com (Steve Patlan)

 

This comparison inspired me to show these details at the interface in a more real way, whereby I was starting with the cladding of the Upper Strut. But since I had already glued the struts at the right SRB, I've taken the struts of the left SRB and first removed the annoying bobble.

 

 

Then I've drilled off a Styrene Rod (Ø 3 mm) step by step up to Ø 1,4 mm,

 

 

so that a separated sleeve of it could be pushed over the strut. In between there was placed a punched disc (0,25 mm, Ø 3,4 mm), 

 

 

which then was glued together with the sleeve on the strut, which already looks more similar to the original strut.  

 

 

 

 

The  same procedure I will now carry out on the right SRB Strut, for what I will carefully separate it off the booster.

 

And now once again to the connecting cable tray between ET and SRB Attach Ring, for what I once again did use this overseeable photo of the ET-32 ( STS-32) by George Gassaway, what I've turned by 90° for better orientation, from which I've also determined the dimensions (in mm) of the individual details.

 

Therein one can also see well the green drawn TPS Cladding, which lies in front of the Cable Trays like an oblique ramp and should have a similar protective function like those of the elongated LH₂/LO₂ PAL Ramps in front of the cable trays in the middle and front tank area. 

 

Source: georgesrockets.com (George Gassaway)

 

With these dimensions I have drawn this sketch (1:1),

 

 

which I then have put onto the interface to try on, with which I can mark the masking areas on the ET.

 

 

The remaining dimensions for scratching the parts I've determined from this side view,

 

Source: forum.nasaspaceflight.com (woods170)

 

wherewith again a further small step was done.  

[roma847]

Hello friends,

 

in silent memory of January 28, 1986 I would like to commemorate the tragic 25th Space shuttle mission and the tenth and last flight of the Space shuttle Challenger, which broke 73 seconds after launch ... 

 

Source: wikipedia.org

 

It was the first launch of a space shuttle from the new Launch pad Pad 39B, in the construction of which my friend James MacLaren was instrumental, to what all employees had been proudly looking forward to. All the greater were their disappointment and sadness that the first launch from the new pad ended in such a tragic way.

 

It was the worst accident in US space history by that time, in which all seven astronauts were killed, 

 

Front row (L-R): Michael Smith, Francis Scobee, Ronald McNair;
Back row (L-R): Ellison Onizuka, Christa McAuliffe, Gregory Jarvis, Judith Resnik
Source: wikipedia.org

 

but seven new stars were born!

[roma847]

Hello everybody,

 

don't panic friends, after a somewhat longer break it should finally go on.

 

In the meantime, the second SRB Upper Strut (right) has also been modified by the thicker sleeve, but the strut, unfortunately, could not be removed from the bonding without being damaged and therefore has to be lengthened somewhat, so that the distance of the booster from the ET is correct.

 

 

For the test fitting onto the ET, I was able to use it like this for the time being. Then I've marked the contours for the Longerons and Cable Trays, incl. TPS cladding,

 

 

 

and then taped them off with masking tape so that I can expose the adhesive surfaces again after the flouring and priming/painting.

 

 

 

Then I took a closer look at and measured the SRB front parts (SRB Forward Skirts) from the Newware Kit, the surface of which is surprisingly finely structured and therefore looks much more real than that smooth from Airfix, 

 

 

whereby they come pretty close to the original.  

 

Source: NASA

 

Since the Newware Kit is specially designed for the Revell Shuttle Stack, the question arose whether the SRB Forward Skirts would also match the Airfix-SRBs. But since the diameters of the SRBs of both kits are surprisingly the same (Ø 26 mm), I was relieved and have carefully cut off the front part with the fine saw.

 

 

 

And lo and behold, the Newware Forward Skirt makes a good match with the Airfix booster

 

 

Now I just have to drill the hole for the brass support rod in the right place and take care that the drill does not run away in the Resin part.

 

 

So I'm still trying to figure out how to do it best ... are there any thoughts?  

 

We will see ...

[xffw45343tg]

Good to see you back at work, Manfred.

 

I have no "tried and tested" suggestions for the drilling, but it seems to me that you need to be able to mount the resin in a jig so that it won't move and then drill the hole using a vertical drill stand. Perhaps 2mm styrene sheet or even foam board would do for a jig? A cut out when the pipe duct fits would stop if from rotating. I'm sure your eventual solution will be more elegant than this.

[roma847]

Thanks Kirk, 

 

to hold the resin Forward Skirt in a jig or a vice, so that it won't move, is the way to go.  The problem is only the vertical guidance of the drill by hand, without a  suitable drill stand. 

 

 

 

 

[roma847]

Hello everybody,

 

I actually don't need to drill 25 mm deep holes, because 5 - 10 mm should also be enough if I shorten the  brass support rod on both sides accordingly. Therewith the boosters' forward attachment point should be fixed sufficiently and, together with the rear SRB Aft Attach Struts, ensure a stable three-point support of the boosters.

 

This is this circled wedge-shaped Fastening part (SRB/ET Forward Attach Fitting) between the ET and the SRB, in each of which is a Separation Bolt, which is blown up together with similar bolts in the rear SRB struts when the SRBs are separated from the ET and thus releases the booster.  

 

Source: NASA

 

Source: Marshall Space Flight Center, Space Transportation System HEAR No. TX-116

 

As one can see in this image, this fastening wedge is in place on the Airfix booster, but it is missing on the Newware SRB Forward Skirt, what in turn proves that apparently no kit is perfect.

 

 

Therefore I will scratch this wedge-shaped part and glue it to the attachment point behind the drilled hole for the support rod, with which the attached booster will be glued onto the ET, which should ensure a sufficient hold.

 

And these 5 - 10 mm deep drilled holes should be carried out by hand with the appropriate caution and care, I hope so.

[roma847]

Hello everybody,

 

and thus to my test bores in order to test whether the minimum depth of approx. 5 - 10 mm could be achieved by hand with an appropriate caution and care.

 

Since my Dremel is already nearly 10 years old, I wanted to test it once again in the associated drill stand, although I had doubts whether the lowest speed of 10.000 rpm already would be overkill and too risky.   

That's why I started by doing some manual tests true to the motto Better safe than sorry!.  For this I have clamped a Resin strip in my Mini vice and started turning the Dremel-chuck with a drill Ø 1,3 mm in the Dremel-stand with the left hand , while at the same time I've soulfully forced down the lifting rod with my right hand, which was not so easy.  

 

 

While the orthogonality of the bore in longitudinal direction was acceptable,

 

 

it left something to be desired in the transverse direction,  

 

 

which is why I was not completely convinced of this hand-drilling variant.

 

Therefore, in a second series of tests with the Dremel in the drill stand I have drilled at the lowest speed (10.000 rpm) in a Chipboard with Ø 1,3 mm,  

 

 

what went smoothly.

 

 

Then I've drilled with Ø 1,4 mm and then took a look at the orthogonality of the bore in the longitudinal and transverse directions, which looked surprisingly good at least over the minimum length.  

 

 

 

Then I've drilled with the diameter of the SRB support rod (Ø 1,5 mm) and tested again in both directions, whereby the orthogonality was still unchanged good.

 

 

 

And the support rod also fit well into the bore, which was about 15 mm deep, which should be sufficient for the stable fixation of the boosters in my opinion, whereby I still could then drill a bit deeper with a Mini hand drill.  

 

 

 

So I could now venture on the bore of the two SRB Forward Skirts from the Newware Kit, whereby in addition to a stable support in a corresponding holder, especially the skirts have to be precisely aligned so that their bores are in line with the support rod.

[roma847]

Hello everybody,

 

so far so good.

 

Next, I've determined the position of the base point for the bore of the Support rod, which was not so easy, because it could not be marked in the narrow space, which is why I had to improvise a little bit with masking tapes.

 

 

The next problem was the necessary level support of the part as a prerequisite for an exact drilling, which was also not easy due to the disruptive Systems Tunnel at the bottom, which is why an exact clamping in the vice was rather difficult.

 

 

That's why I clamped a brass angle for orientation in the Z-direction, 

 

 

and aligned the center line on the back of the part as good as possible parallelly.  

 

 

For the alignment in the X-direction I oriented myself on the upper edge of the vice.

 

 

For better orientation here one can see the Orbiter vehicle coordinate system.  

 

Source: Marshall Space Flight Center, Space Transportation System HEAR No. TX-116

 

And in this position I will try now drilling the hole, again step by step, carefully pre-drilling with Ø 1,3 mm, and then drilling out with Ø 1,4 mm and Ø 1,5 mm.

 

Hopefully I can do this successfully, so please keep your fingers crossed!  

[roma847]

Hello everybody,

 

but there is also a more precise method to mark the bore point on the SRB Forward Skirt. To do this, I colored the front face of the holding rod with ink and then placed it on the ET's Intertank, which allows a contact line to be marked. The more precise point for the bore results at the intersection of this line with the longitudinal engraving on the skirt. 

 

That's why I applied this method also still at the right SRB skirt with the tapes, the result of which can be seen here. 

 

 

The more precise point is therefore a littele bit further ahead.

[roma847]

Hello everybody,

 

and therefore: Nothing ventured, nothing gained! - Let's get on with it!

 

Before with drilling it could really come down to business, the vice onto the drill stand was carefully aligned so that the drill came to stand directly over the pre-drilled hole, whereupon this arrangement was then firmly fixed to the table top with a screw clamp. 

 

 

 

Then, as with the test bores, the holes were drilled step by step, first carefully pre-drilled with Ø 1,3 mm, after which this bore was then drilled out with Ø 1,4 mm and Ø 1,5 mm to a depth approx. of 20 mm.

 

And as the following two images show, the orthogonality was surprisingly good in both directions.

 

 

 

Then the front part was inserted into the booster and with the bore put onto the Support rod in the Intertank, as well as put down with the two rear struts above the openings at the ET's rear, 

 

 

whose feet had to slightly ground until they fit in the openings.

 

 

At the front end a Balsa board (2 mm) was inserted as a spacer, 

 

 

 

since the already mentioned SRB Thrust Fitting has to be glued directly behind the support bar, which is unfortunately missing at the Newware front parts,

 

Source: NASA

 

which is why I have to scratch this part.  

[xffw45343tg]

Looks perfect.

Just as an aside, Manfred, am I right in understanding the Shuttle sits at a slight angle to the vertical just before takeoff and the torque of the (offset) main engines brings it vertical just before the SRBs are ignited? I don't know whether this is true, but since I was told this, it always looks that way to me on videos.

[roma847]

Thanks Kirk for your compliment.  The effort was worth it.

 

What you mean is a process NASA engineers call it "The Twang".  This is because when the SSMEs ignit, the force of that thrust actually causes a movement of the upper part of the ET backward by up to one metre, and it takes sevral seconds for it to swing back to vertical. The SRB ignition happens just at that moment when the stack is back in the upright again. 

[roma847]

Hello everybody,

 

the same drilling procedure I have now carried out with the right SRB front part, which has been similarly good and successful.

 

And so I have now been able to attach both SRBs provisionally at the ET, what fits together quite well and also looks good, in my opinion.  

 

 

 

And since  there was nothing to be seen of the MLP for a long time, I took it out of the closet and put this ET-SRB-Troika on it.

 

 

 

 

 

That should it be for today.

[roma847]

Hello friends,

 

unfortunately I was out of action for a while because my PC gave up the ghost,   but my son has built me a new one so that it can go on. 

 

Now that my new PC is running, it can finally continue on the Stack-construction site,  whereby it specifically concerns the front connection points between the ET and the SRBs, these are the so-called ET/SRB Forward Attach Fittings, one of which was already shown in this picture, whereby the cladding over this green segment is missing. 

 

Source: NASA

 

Apparently, this is not just a cladding, because as one can see in this photo of the STS-6 Stack in the final state before the launch of the Challenger, there are two white boxes stacked over one another. Since this image shows the front of the stack facing the orbiter, the question immediately arises as to how this connection assembly may have looked on the back. 

 

Source: forum.nasaspaceflight.com (woods170)

 

To find out, I had to do a bit more research and have found this photo of the ET-121 after its separation from the Discovery (STS-114), that was the so-called Return To Flight Mission after the Columbia disaster (STS-107). 

 

On that one can see on the underside, although a little small,  the part of the fitting that belongs to the ET. The rest of the part is therefore on the previously blown away Booster. 

 

Source: NASA

 

The following photo montage shows how the two assemblies of the attachment fit together. 

 

 

Helpful for my understanding were these drawings of the Attach Fitting, on which the parts belonging to the ET are colored green and those of the SRB are blue, which are connected by the Separation Bolt. 

 

  
Source: System Definition Handbook SLWT, Vol. I (Lockheed Martin)

 

Final clarity about the arrangement of the fitting on the front I then got through these two photos,  here in opened state without cladding (RSS Fairing)

 

Source: NASA   

 

and here with the gray cladding,

 

 
Source: spaceflight.nasa.gov                                                                                                                                          

                                       

which I then compared directly in this photo montage. 

 

 

Unfortunately, I did not have these photos available during the failure of my PC, which is why I've initially only orientated myself by the first photo at the beginning of the post that I had on my smartphone, but what unfortunately has led into the wrong direction when I began scratching the arrangement,   but what I still want to present to you.  

 

When scratching this fitting, I had to consider the support rod for the SRBs and drill a respective boring.

 

For the two-part basic body of the fitting I've used a Rectangular profile (2 mm x 2,5 mm), which I rounded off at the front end to simulate the Bolt Catcher and drilled out for the holding rod with Ø 1,5 mm, as one can see in this image. 

 

 

On this image one can see the assembly of such a Bolt Catcher, which catches the front part of the bolt that was blasted off when the booster was separated,

 

Source: NASA

 

whose honeycomb-like inner structure can be seen here in detail.  

 

Source: NASA

 

The individual parts of the ribbed back part I cut from an Evergreen Strip (0,25 mm x 2,0 mm),

 

 

and then glued step by step with MEK onto the basic body laying on a Teflon foil.

 

 

Gluing the tiny triangles was a pretty tricky task due to the minimal spacing, 

 

 

but has worked well thanks to my angelic patience and steady hand. 

 

 

This was followed by the side attachment of the boxes on the front, which I could only reconstruct on the basis of my smartphone picture, 

 

 

what then looked like that. 

 

 

For modeling the arrangement on the back I've used this photo of the ET-45 (STS-47), although one can only guess it. 

 

Source: georgesrockets.com (George Gassaway)

 

But I think that it can only be a simple cover, if one looks at this zoom shot,  

 

 

which is why I've chosen this simple form. 

 

 

And so the finished fitting sits on the SRB,

 

 

and that's how the whole thing looked with the attached SRB onto the ET, actually not bad, right? 

 

 

But now I'm a bit smarter  and know that the two boxes on the front are not sitting next to each other but have to sit one above the other, which is why I still have to change it once again, but be that as it may!  

[roma847]

Hello everybody,

 

today is an important historical date for my project, which I would like to honor with a brief review.

 

37 years ago today, on 4 April 1983 took off from the Launch Pad 39A the Space shuttle Challenger for her maiden flight, the STS-6 Mission, to whom I have dedicated my long-term project.

 

Source: NASA

 

And now back, here comes the next update. In the meantime I have modified the ET/SRB Forward Attach Fittings a little bit, so that the two boxes with the cabling are now arranged one below the other as in the original, as was already shown here.

 

Source: forum.nasaspaceflight.com (woods170)

 

Admittedly, this is only a small part of the entire Shuttle stack and can hardly be seen in the end, but if I am not completely convinced by the details, then I get to the bottom of the matter once more, something this time took longer because I've  researched some sources more exactly again.

 

And this is how the new part looks with the boxes arranged one below the other,

 

 

and here again in direct comparison with the previous variant (left). 

 

 

Since the new prototype initially seemed a bit too big to me, I've reduced it a bit in a second variant (below),

 

 

what one can see here.

 

 

But after a detailed re-measurement based on the original photos, I still decided on the first, slightly larger version and made a copy of it for the other fitting.

 

 

In the meantime I have also found a photo of the back of the fitting (left), which at first glance hardly differs from the front side (right) where the two boxes with the ET/SRB RSS cross-wiring were mounted.

 

Source: forum.nasaspaceflight.com

 

On the back there are no additional attachments like on the front, but only the receptacle for screwing the Ground Handling Fitting for the transport of the ET, 

 

Source: System Definition Handbook SLWT, Vol. I (Lockheed Martin)

 

which was probably covered with a cladding, which one can guess more on this picture than can see clearly,  

 

Source: georgesrockets.com (George Gassaway)

 

what I simulated by these tiny parts.

 

 

And so these attachments sit opposite each other when installed on the SRBs.

 

 

 

 

And this is how they look in the glued state, here is the view of the front of the ET, which is facing the orbiter,

 

 

and here's a look at the back.

 

 

And with that I wish everyone a nice Sunday, and above all, stay healthy.

[roma847]

Hello everybody,

 

unfortunately there are a few inconsistencies regarding the front and back of the ET/SRB Forward Attachment, which still seem suspicious to me.

 

On the left during the Rollout of the ET-8 (STS-6) one can clearly see the FWD Hoisting Lug sitting on the "front side" of the ET and pointing up , and on the right, what also shows the ET-8 "front side" it looks like the arrangement with the ET/SRB RSS cross-wiring, strange ...

 

That doesn't go together ...

 

 

The same arrangement can be seen in this photo from the STS-8,

 

Source: forum.nasaspaceflight.com (Ares67)

 

as well as from the STS-9 too.

 

Source: NASA

 

Both arrangements would correspond with that of the STS-6 (first image, right).

 

On the other hand, there are no holes on the FWD Hoisting Lug (right) for the assembly of the ET/SRB RSS cross-wiring boxes, which one can see in the left image.

 

Source: forum.nasaspaceflight.com (Jester)                                                                      Source: live.staticflickr.com (S. Patlan)

 

But in this screenshot from a Pad 39A walkdown video taken during the STS-133 pad flow it can be seen that these ET/SRB wiring boxes (with a gray fairing) are not sitting on the "front" but on the "back" of the ET (the side that facing away from the orbiter). Now the expert is amazed, and the layperson wonders, right?

 

 

This view shows up at 2:36, here you go! 

 

https://www.youtube.com/watch?v=Fj-CCf8vExE

 

How does that fit together, or not, what do you think about it?

 

Maybe someone here in the forum knows about this matter?

[Major Eazy]

 

@roma847

 

WOW!

 

Looking at all of your work in progress photos, it's like going on a field trip to the blacksmith and watch the guy doing metalwork. It's impressive to see someone like you showing your work in progress photos. I can hardly wait to see the finished model kit. Keep up the good work and take care of yourself.

[roma847]

Thanks for your interest and the nice compliment. 

 

It has been a long and winding journey ... 

[roma847]

Hello everybody,

 

in our German Raumcon Forum I received a tip about the "Space Shuttle Technical Conference" from 1985, the both parts of which I found on the NASA Technical Reports Server (NTRS) and have skimmed over Easter. Part 1 (227 MB) - Part 2 (198 MB) ...

 

Unfortunately, I could not find any information in order to clarify the said discrepancies regarding the ET/SRB Forward Attachments, which I have noticed on some early missions' photos.  

 

Regardless of this, one can find a wealth of interesting information in the conference contributions, which I have looked at here and there in more detail, provided that they did concern the ET and/or the SRBs and contained corresponding photos.

 

And so I'm among others came across a Term I had been tampering with for a while already without getting to the bottom of it ...  

 

This is the term RSS Fairing, which was most recently used in this drawing of the Forward attachment.

 

Source: System Definition Handbook SLWT, Vol. II (Lockheed Martin)

 

The term Fairing as such was already familiar to me from the front fairings of the LO₂ Feedline and the GH₂ Press. Line on the Intertank.  

 

I was only irritated by the abbreviation RSS, which I'm of course familiar regarding the Rotating Service Structure, but wich has nothing to do with it.

 

But as I have now learned from a conference contribution (EXTERNAL TANK PROCESSING FROM BARGE TO PAD), with RSS is meant the so-called Range Safety System, which I did not know so far, but which was of extraordinary importance as a safety system for all shuttle missions.

 

And as it is often the case, I was so interested that I pursued this in a targeted manner and tried to find out more information about the task and function of the RSS.

 

With this is also related to the term ET/SRB RSS cross-wiring, which my friend DaveS from the NASA Spaceflight Forum mentioned during a lengthy PM chat, which only increased my curiosity.

 

And with that we are right back to these white boxes on the "front" of the ET/SRB Forward Attachment,

 

 

which can be seen here both in the opened and in the cladded state, the upper half of which belongs to the ET and the lower half to the SRB. In the left image one can see the RSS cabling between the ET and the SRB for the STS-103.

 

 

The Space Shuttle's Range Safety System (RSS) thus enables the destruction of both the SRBs and the ET using on-board explosive charges (Linear Shaped Charge, LSC) by radio remote control from the ground station by the Range Safety Officer (RSO) in the event that the shuttle stack gets out of control to limit the danger to people and facilities on the ground from crashing pieces, explosions, fire, poisonous substances, etc. ...

 

This drawing shows these LSCs on the ET/SRB, as well as the associated receiving antennas, the Range Safety Command Antennas. 

 

Source: NASA

 

The RSS was only connected to the LSCs, but not to the SRB separation system, which was wired separately. 

 

As I also know by DaveS, the RSS was cross-wired for security reasons, so that an error could not impair the ability to destroy the stack. The cross-wiring ran from the left SRB-RSS through the ET to the right SRB-RSS and vice versa. In this way, failure of one SRB's RSS cabling would not affect its ability to be destroyed, since the security cabling always was ran from the other SRB too.

 

The RSS was activated only once - during the Challenger disaster (STS-51-L), 37 seconds after the orbiter broke apart when the SRBs were in uncontrolled flight (Source: wikipedia.org).

 

And with that once again back to the above-mentioned discrepancies regarding the ET/SRB Forward Attachments.

 

 

These can only be explained by the fact that the RSS cross-cabling in the early missions was probably more done  on the "front" (-Z side) of the ET than on the "back" (+Z side).  

So much for my little Easter walk for those interested.

[roma847]

Hello everybody,

 

after a longer breather I want to get back in so that I can’t get out of the exercise.  

 

Therefore I want to leave the SRBs for the time being and address myself to the ET to start preparing him for the Flour coating, wherefore I first have to glue the tape strips for simulating the SOFI Pattern texture both on the LH₂ Tank and on the LO₂ Tank. 

 

For this I can resort to my preliminary tests from last year, in which I used a 0,75 mm wide tape strip as a continuous spiral (Barber pole) onto the Airfix Intertank which is no longer required, 

 

 

 

which at the time looked like this after the Flour coating.

 

 

So I came very close to the pattern texture of the ET-8, whereby the final result should probably look even a bit better after priming and painting.  

 

 

As one could see at this image, the SOFI patterns on the ET Aft Dome are significantly wider than on the front part of the tank, which I wanted to take into account.

 

Source: forum.nasaspaceflight.com (Jester)

 

After taking a closer look at this structure once more, I decided to use 1,5 mm wide tape strips, of which I've then glued short strips on the Aft Dome at intervals of about ≤ 1 mm for testing. Before that, of course, I had removed my fragile Aft ET/Orbiter Attachment and put it in a box to safety.

 

 

On the front part there are glued the chosen 0,75 mm wide strips, at intervals of approx. 0,5 mm.

 

 

 

 

So I could imagine that way.

 

What do you think about it?