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  #1  
Old 06-13-2022, 01:22 AM
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blackshire blackshire is offline
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Default Astra stumbles again at the Cape...

Hello All,

Did you see this morning's latest launch by Astra? It came agonizingly close to succeeding (see: https://spaceflightnow.com/2022/06/...-live-coverage/ , and https://spaceflightnow.com/2022/06/...launch-failure/ ). I was also surprised to hear the announcers refer to its fuel as "RP-X" (every reference I've seen on the vehicle says it uses RP-1, burned with LOX). Also:

I can't help but wonder if their constant "iteration-tinkering" with its design--no two rounds are identical--is at least partly responsible for their so-far poor success record. (The old original Thor-Delta was mostly immune from failures--which were rare, after the first Delta A failed to orbit an Echo satelloon--by using all of the most reliable existing rocket and guidance system hardware, and the design was frozen, with Douglas [later McDonnell Douglas] only making uprated versions "one feature at a time," beginning by 'stretching' the Vanguard/Able second stage's tankage to create the Delta B.) Now:

Astra's vehicle, being a "clean-sheet" design, doesn't have earlier-existing rockets to draw the most reliable hardware from. But if they would freeze its design (at least for a significant spell), and make it reliable through multiple flights (and, as with the Delta, analyze what went *right* with each launch [some things just barely missed working wrong, and were subsequently beefed-up], and what didn't--this was the Delta development philosophy), Astra could make their Rocket 3.3 vehicle (it really needs a proper name! [I suggest "Shire," as "Percheron" has already been used for two rockets, see: https://www.google.com/search?q=Per...sclient=gws-wiz and https://books.google.com/books?id=P...0rocket&f=false ]) as reliable as the Delta, or even more so.
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Old 06-13-2022, 08:31 AM
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tbzep tbzep is offline
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It came within a minute of the 8 minute 2nd stage burn to obtain orbit before early engine shutdown.
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Old 06-13-2022, 09:43 AM
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Quote:
Originally Posted by tbzep
It came within a minute of the 8 minute 2nd stage burn to obtain orbit before early engine shutdown.
*Nods* Yes--and even that need not have necessarily resulted in a "Failed to orbit," as such entries read (before the cause, if known, was included in the citation) in the old TRW Space Log issues. For example:

The first Orbiting Astronomical Observatory, OAO-1 (launched 04/08/1966, and still in orbit), was launched by the only Atlas SLV-3B-Agena D (whose oversized payload fairing made it virtually indistinguishable from an Atlas-Centaur). Very late in the Agena D's burn, it lost guidance control and began tumbling; luckily, the spinning was in the vertical plane of the vehicle's trajectory, so it didn't deviate to the left or right. By sheer luck, it achieved exactly the planned 400 nautical mile-high circular orbit at the planned inclination, despite its spinning. OAO-1 also tumbled, after separation from the Agena (due to the physics of rotating bodies). Also:

SpaceX makes use of this effect, deliberately slowly rotating the Starlink satellites-carrying Falcon 9 second stages in a plane tangent to the orbit (the spin axis points to the Earth's center), to ensure slow but steady separations--of the satellites from the second stage, and of the satellites from each other. Unfortunately, despite OAO-1's "lucky launch," its power supply failed, and it died of electricity starvation just a few hours later. (OAO-1 would make an interesting "rescue/upgrade" target for a Falcon 9/Dragon in-orbit servicing mission; its telescope door was never opened in orbit, so its multiple interior telescopes--and all of the other equipment inside--should be in "As New" condition.)
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Old 06-13-2022, 02:00 PM
BigRIJoe BigRIJoe is offline
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Blackshire your posts are looked for with eagerness and in the case with ASTRA launch vehicle I think you "knocked it out of the park"
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Old 06-13-2022, 02:06 PM
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Quote:
Originally Posted by BigRIJoe
Blackshire your posts are looked for with eagerness and in the case with ASTRA launch vehicle I think you "knocked it out of the park"


Yes, very high rocketry content score: A+++++++++!

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  #6  
Old 06-13-2022, 03:20 PM
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Quote:
Originally Posted by BigRIJoe
Blackshire your posts are looked for with eagerness and in the case with ASTRA launch vehicle I think you "knocked it out of the park"


-and-

Quote:
Originally Posted by Earl
Yes, very high rocketry content score: A+++++++++!

Earl
Thank you both--this will be a happier day for me, thanks to you! (Living alone, it's easy to stew in one's own thoughts, especially when reminders of one's mortality--such as James Eugene Seals' [of Seals & Crofts: https://www.youtube.com/results?sea...t s+full+album ] death last week--start occurring more frequently.) As my late friend Gary Moore said after such events, "All of our names just moved up a notch" (I prefer to think of it as being a little closer to getting my hooves back).
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Old 06-13-2022, 05:31 PM
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Blackshire ALWAYS provides a plethora of good information in his posts.
Always appreciated !
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Old 08-11-2022, 08:55 PM
frognbuff frognbuff is offline
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Astra is finally dumping the "Rocket 3.3." It's too small and unreliable. Next up - "Rocket 4.0!"
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  #9  
Old 08-15-2022, 07:08 AM
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Quote:
Originally Posted by ghrocketman
Blackshire ALWAYS provides a plethora of good information in his posts.
Always appreciated !
Thank you, GH--you've also lifted my spirits at a time when it helps! As well (if memory serves):

You had mentioned rockoons as scale model subjects recently (Luis Eduardo Pacheco's "StratoCat" website covers rockoons and other Skyhook-type stratospheric balloons and missions: http://stratocat.com.ar/indexe.html ), and I found a couple of eclectic books about balloons--including the plastic film Skyhook-type ones--that show how to properly shape the gores to get the right scale "teardrop bubble" (at launch) and "giant onion" (at maximum altitude) envelope shape, including for "natural shape" balloons (which some of the biggest Skyhooks were and are).

Natural shape balloons have flat, or mostly-flat, tops. They're often--if not always--used for lifting heavy payloads, and they only have envelope stresses in the vertical direction (or nearly only in that direction, to minimize stresses on the plastic film); the vertical gore seam seals, which double as load tapes, take up the load, and:

Model Skyhook balloons are easy to make out of the thin polyethylene plastic film dry-cleaning clothes bags, which are available by the box, including on Ebay (they're also called "Garment Bags" or "Garment Covers" [see: https://www.ebay.com/sch/i.html?_fr...g+bags&_sacat=0 ^and^ https://www.ebay.com/sch/i.html?_fr...+bags&_osacat=0 ]; it's the same plastic that full-scale Skyhooks are made of, except that they're often of even thinner-gauge plastic! The gores can be joined using narrow cellophane or Scotch/3M tape (craft stores sell narrow-width rolls of it). I'll post all of this material separately, on the Scale and Sport Scale sub-forum.
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Old 08-15-2022, 09:36 AM
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Quote:
Originally Posted by frognbuff
Astra is finally dumping the "Rocket 3.3." It's too small and unreliable. Next up - "Rocket 4.0!"
I have a question about this, but first: I found an article that provides some information about the new vehicle:

Here (see: https://spacenews.com/astra-reveals...-larger-rocket/ ) is a Space News article--with an illustration--about Astra's Rocket 4 (which is part of what they call "Launch System 2.0"--a higher flight-rate, lower crew-size, easily-transportable [in shipping containers] total system), which is significantly different from Rocket 3.3. (I didn't see any more information on Astra's https://astra.com/ "Newsroom" page, but I might have missed something from a few months back; the Space News article itself is from May 12.) In addition:

Unlike the plans for Rocket 3.3's first stage, Astra doesn't plan for Rocket 4 to be reusable. (They're going "to MCD rather than to reusability"--MCD is engineer Arthur Schnitt's [of the Aerospace Corporation, a think tank] Minimum-Cost Design philosophy, where cost is traded along with performance when designing rockets and spacecraft.) Russian and Chinese ones are similar to MCD designs, see: "LEO on the Cheap: Methods for Achieving Drastic Reductions in Space Launch Costs," by John R. London (here's a free PDF copy of it: http://foyle.quarkweb.com/lc93/leocheap_book.pdf ). Also:

Rocket 4 will have two larger, turbopump-fed (rather than electric, battery powered pump-fed) kerolox first stage engines that produce a total of 70,000 pounds of thrust (35,000 lbf each; no information on the upper stage engine/engines was available). The 35,000 lbf engine *could* possibly be Firefly Aerospace's Reaver engine, or a similar derivative (it was reported last year--a link is in the Space News article--that Astra discussed licensing Firefly's Reaver engine, whose parameters are similar to Rocket 4's first stage engine. The vehicle is designed to inject a 300 kilogram payload into low Earth orbit (or 200 kilograms into Sun-synchronous orbit) for $3.95 million. Now, the question that occurred to me is this:

With the orbit-capable Rocket 3.X vehicles Astra flew, second stage separation--as it appeared in the onboard camera views--never looked "solid" and "positive" to me (as the Saturn, Thor-Delta, Atlas-Centaur, Delta II, Delta IV, Titan III & IV, Commercial Titan, Atlas V, Electron, Ariane, and Falcon staging did/do), even on the successful Astra Rocket 3.X missions that did reach orbit. It was always a slightly delayed, "cliff-hanger" moment before the fairing halves separated, even after they fixed the delay (implemented the proper delay time, that is, so that the second stage/payload wouldn't slam up into the still-"un-split" & un-separated payload fairing. The delay times, even after having been fixed, also seemed slightly variable from flight to flight, which seems to have "fit in" with something else (which is unwise to do with rockets):

From everything I've read about Astra (including comments from CEO Chris Kemp, and other company personnel), no two Rocket 3.X or Rocket 3.3 rounds were identical; they were always "tinkering" with the designs (Rocket 3.3's most noticeable change was its "stretched" first stage tankage), making endless iterations--even after successful orbital launches had been conducted. Was this the case? If so, that sounds like an unwise way to develop a reliable launch vehicle, for this reason:

If one tests a prototype of anything, especially if it's intended for mass production (be it a rocket, car, airplane, weather balloon radiosonde, etc.), and it works as intended, tinkering with it seems foolish--*unless* telemetry and/or physical inspection (if possible) reveal(s) that one or more parts or systems very nearly failed during the test run or flight. Now:

(A famous example of NOT doing this--which resulted in high reliability--was the development of the Thor-Delta launch vehicle. Douglas used already well-proved components--the Thor first stage, the Vanguard second the third stages [Able and Altair, respectively], the Thor-Able bulbous nose fairing [a cone-cylinder fairing, for narrower payloads, replaced the hemisphere-cylinder Thor-Able fairing], and the AC Spark Plug Titan I guidance system--in the Thor-Delta, only making changes--and usually only one at a time--when they gradually upgraded the vehicle for higher performance.) But they flew each uprated variant a number of times, to be certain it was fundamentally sound, before incorporating the next upgrade, BUT:

Astra's vehicles, having precious few previous flights to draw upon for experience (and for making meaningful reliability computations; their "sample size" was essentially *one*...for each iteration, making such reliability calculations nearly meaningless), were the least "well-placed" for doing such iterations on. If they continue this way of doing things with Rocket 4, they will likely have the same problem; when each round is a "one-off," figuring out--even with telemetry--what "failure chains" are likely, and why--will be much more difficult than "freezing" (at least for a while) a design that works, and flying it numerous times to prove its reliability. (Douglas [and later, McDonnell Douglas] even investigated why *successful* Thor-Delta and Delta II flights worked, to find and fix [or beef-up, as appropriate] any marginal parts or systems that hadn't failed, but could easily do so, if they weren't lucky.) Plus:

I remember Astra CEO Chris Kemp comparing their launch vehicles to computer software (he came from a Silicon Valley background, if memory serves), which is behind their philosophy of "continuous iterations" of their rockets' designs (in total, they've built--and static-tested, and launched--several), from their original Ventions design to Rocket 1, Rocket 2, and Rocket 3 (in all of their iterations); the launches took place from our Pacific Spaceport Complex - Alaska (PSCA) on Kodiak island. Tinkering with computer programs is one thing (even the most spectacular Kerbal Space Program launch pad explosions and in-flight failures cost nothing), but doing the same with even the smallest orbit-capable *physical* rockets involves expending money, time, and materials, and creating some risk to company--and even flight range--GSE (Ground Support Equipment) and--in the latter case--the range's buildings, cranes, tracking facilities, etc.! :-)
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http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
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