Thursday, July 23, 2009

1000 Visits, No Steenking Carbon Credits Required!

ZZakk's Lab passed the 1000 visitor  mark today.
Not bad for a blog that's only 5 months old, with 34 posts.
I swear, I accounted for no more than 200 of them myself.
250 tops.  By May the count had crept up to 138 for the
month. June practically exploded with 345 visitors. July
may edge that out by a few.  According to the average visit
duration,  most visitors are even staying long enough to read
Thank you everybody.

Wednesday, July 22, 2009

Such a great idea...

Such a great idea, yet even Estes doesn't seem to
want to build one. WTF?
In the 1997 Estes catalog there was a kit that never
reached production. It was a model of a fly-back booster
called Star Booster. It's based on descriptions in Buzz
Aldrin's sci-fi book; Encounter with Tiber. copyright 1996
Great book by the way. I dug it up for this post and then
read it all again.

In the book, the Star Booster is built by Boeing to take
a slide-in Zenit motor/tank assembly, built under license,
in the USA. One or two of them would be attached to a
core vehicle as a strap-on like an SRB is. After using up
it's propellants, the Star Booster would seperate from the
core vehicle then glides back to an automated runway
landing near the launch site. After each flight, the Zenit
is removed for seperate servicing. When the airframe is
ready, the next available Zenit gets installed for a quick
BTW; Boeing really is building licensed Zenits for the
Sea Launch commercial launch program.

The Estes Star Booster model was going to be 18" long,
with a 9.5" wingspan, parachute recovery, C motors only.
By the looks, I expected it to have a cast styrofoam
fuselage over a cardboard core tube, just like the large
Shuttle Orbiter kit of the same time period.

I've been looking at the Estes Star Booster recently  with
ideas for reproducing it. I have hot-wire foam cutting
equipment, so it's not a big stretch for me to model it at
the original size or larger.  The difficult part is that not
only do I want it to glide, I want it to glide with an unfair
chunk of reload casing inside it. In short, a realistic mission
as afly-back strap-on,  boosting a level 2 size rocket.  For
the sake of balance it needs a long thin motor case.  Either
a 29/360 or 38/480+ sized case, probably EX  and burning
sugar. The big trade-off [ya can't design anything without
trade-offs] is, to maintain balance, the bigger the  model,
the longer the motor case needs to be, and  vice-versa.   
Of course, it'll glide like a brick!

For more info see;  Fly-Back Boosters, Reprised
right here at ZZakk's Lab on Monday, May 18, 2009
These 2  posts [of 3 before long] were supposed to coincide
more closely, but I'm easily distracted.

Friday, July 17, 2009

Uncle Walt Believed

Early today I read that NASA released some early photos
from the LRO, Lunar Reconnaissance Orbiter, showing
most of the Apollo landing sites on the moon.
Curmudgeons Corner, the blog that clued me in,  said that
the conspiracy nuts are now invited to apologize and then
shut up.   My first thought was that this is a NASA
spacecraft and therefore not independant coroboration.  

I didn't bother leaving a comment, let alone feeling the
need to compose this post.

On the evening news I found out that Walter Cronkite
passed away today. I grew up watching Uncle Walt on
the news.  He was a great great man, and a first rate
journalist.  He was also a staunch supporter of the space
program, but no wide eyed fool.  So, here's my answer to
all the lunar landing hoax theorists;  

Walter Cronkite believed!

Goodbye Walt, you'll be missed.  11/4/16-7/17/09

Monday, July 13, 2009

MLAS of the Future

The illustrations above show what the MLAS shroud
will look like in the near future, more or less.

Obviously it was drawn when the number of motors
were to be as many as six, the version just flown
is designed to use only four motors. The folding grid
fins are shown though, and four is the number since
no matter what, one side is reserved for crew
access.  Once the MLAS gains it's grid fins, the boost
test vehicle will lose it's coast skirt and associated
upper finset. Depending on the  nature [flight
envelope] of the future tests, the test  booster will
mutate further still.   MLAS's current good looks are
probably a one shot deal.

Before a live MLAS shroud abort flight can take
place, the motor manifold connecting the four
shroud motors around the apex will have to be
ground tested. That'll be an event to look for in
future NASA news releases.

The Block I & II Ares LAS uses a single abort
motor that is mounted upside down, with the exhaust
flowing through a hot manifold to turn it around
approxx 135deg in order to exit the nozzles, this
constitues a large weight and performance penalty.
Scary hot too.
With the MLAS motor system there are multiple
motors which all must ignite. Of course, the motors
and ignition systems are very reliable, but just in
case, the motors will be interconnected with a
manifold at the top end. This allows exhaust gasses
from the other three to ignite the stubborn one.
Since gas cross flow will be minimal once all motors
are lit, the MLAS manifold will run a lot cooler and
can therefore be made a bit lighter than on the LAS.

BTW;  Rumor has it, Quest is fast tracking an 
MLAS modroc kit.  

Wednesday, July 8, 2009

MLAS takes to the Air!

Wahoo!  Look at that gooneybird go!

After several delays in June, I found yesterday that the
MLAS was scheduled to fly this morning 7/8/09. Well
it took off at 6:25AM ET, which is soon after the launch
window opened, so it seems the countdown went well.

There are only a few sparce articles out so far, but that
should grow, shortly. I've seen 2 ascent pics so far.  
Despite the massive base drag, I was hoping to see the
individual flames of the severely canted boost motors,
however you can seethe lobes they create in the smoke
Now that the MLAS has made it's 1st successful flight,
it paves the way for the rest of the MLAS test program.  
It also takes it from an interesting sport modroc and turns
it into a legal NAR scale subject.

The 2nd pic above is NASA's picture of the day today.

Monday, July 6, 2009

The Orion Abort Test Booster, Almost.

I Found it! Almost.
This info is less than a year old, so it's practically current.
This hasn't been an easy search, I had to buildup a string of
clues. I knew the test flights would occur at White Sands Missile
Range. I more or less trolled through the NASA facilities until
I found that NASA's Dryden Flight Research Center at Edwards
AFB has the project. Dryden is responsible for vehicle integrations
and ops.

The linked Dryden document below is a treasure trove.

I found that Orbital Sciences Corporation, Chandler, Ariz. is
constructing the Abort Test Booster. Thus the all important
acronym; ATB. For a successful technical search, having the
correct acronym for a keyword can be crucial. Even when I
went to the Orbital Sciences website it took a bit of searching,
I had to use their search box, but "ATB" gave up a bunch of
documents.  Unfortunately for me, the 4.1MB PDF fact sheet
wouldn't open once I downloaded it. My PC OS is too old.
So far, all I've found are illustrations, and not photographs,
thus the "Almost" in the title. But good illustrations they are,
with versions for both Block I and Block II LAS's

Motive power is going to come from surplus Peacekeeper ICBM
1st stage motors. Given the current lack of fins, no doubt the ATB
will use the stock Peacekeeper thrust vector system. The flight
control system will probably be based on the same modular system
that Orbital Sciences developed for their other programs. Orbital's
new Minotaur IV & V already uses Peacekeeper motors, so that
should be a slam-dunk.

Friday, July 3, 2009

Ares Launch Abort Systems Block I & II

The above NASA document shows the difference
between the Block I, called PA-1 here [Pad Abort],
and the Block II design with the curvy bullet shaped

The Mercury capsule flew with the abort tower
attached directly to the capsule. With Apollo, the
designers added the BPS, Boost Protective Shroud.
I've seen it called BPC, Boost Protective Cover too.
This was a large metal conical cover over the capsule.
The BPSserved double duty; as extra protection for
the capsuleduring an emergency seperation [possibly
allowing a reduction in capsule weight], and the BPS
acts as a stabilizer when the tower motors are fired.

When NASA designed the Launch Abort System for
the Orion capsule, they logically started with the
Apollo system, with a few changes to make it more
compact. Compact usually translates to weight savings.
The obvious change was the deletion of the open struts
that seperate the abort motor nozzles from the BPS.  
In the Orion system this space is taken up by the
seperation motor itself, which is mounted upside down.  
More about that little kluge at a later date.

This all sounds fine and dandy so far.
The other pic is a wind tunnel model of the Ares 1
with visible shock waves. This is a common wind tunnel
technique for researching different designs. As you
can plainly see the biggest shock wave is generated by
the Orion BPC. NASA says they have no problem with
controlling the Ares 1, but any hobby rocketeer can
tell that aint very stable. Not stable at all.
Saturn Apollo didn't have this problem. The Apollo
capsule and BPS were much smaller than Orion and, as
I recall, the biggest shock wave producer on the Saturn
was the reducer, between the 2nd and 3rd stage, which
is further back on the airframe. OTOH; the 1st stage of
the Ares 1 is smaller in diameter than the 2nd stage and
capsule, making the situation even worse.  Natural
stability is no big requirement for modern rocket systems
with computer guidance systems and gimballing nozzles,
but the Big Stick is pushing the envelope here.

Enter the Block II BPS.
The modern BPS's are made of composites instead of
metal, which is sensible, but the Block II will  certainly
weigh a fair bit more than the Block I.  With it's bullet
shape, the Block II drag reduction will be huge and
therefore controllability margins will be enhanced.

Ares 1X, the 1st test flight of the Ares 1 stack will
use a Block 1 BPS. Hopefully later tests will include
Block II or even MLAS.