Barely spacex related, but it's boring here in mission control right now. 
We're launching tonight at 9:43 eastern.
Vega Flight VV07 - Arianespace
We're launching tonight at 9:43 eastern. Vega Flight VV07 - Arianespace
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adiggs
Well-Known Member
adiggs
Well-Known Member
adiggs
Well-Known Member
Solid motor - that means the propellant is solid, and once lit, it burns until gone - is that correct?
The other thing that struck me - the rocket was nearly binary; it was off, then it was on (and gone). Is that a difference in holding the rocket down when the motor first starts up?
The other thing that struck me - the rocket was nearly binary; it was off, then it was on (and gone
). Is that a difference in holding the rocket down when the motor first starts up?
Thanks for posting.
It definitely is. With liquid fuel you want to confirm everything is working properly before the rocket leaves the pad. With a solid rocket motor it is going to fully fire no matter what. So light it and let it fly.
I like the color change of the exhaust as it burns through the fuel. That's fun.
The other thing that struck me - the rocket was nearly binary; it was off, then it was on (and gone
It definitely is. With liquid fuel you want to confirm everything is working properly before the rocket leaves the pad. With a solid rocket motor it is going to fully fire no matter what. So light it and let it fly.
I like the color change of the exhaust as it burns through the fuel. That's fun.
Yup. It's a solid material that's a volitile recipie of fuel and oxidizer in a binder material that then gets pressed into interesting shapes (on the inside--the outer diameter is just circular) to create unique burn profiles. It's sort of like a dura-flame on steroids, if you bored a hole down the length of the log and let it burn from the inside out. Once you light it the log is [relatively] hard to extinguish. Change the size/depth of the hole and the log might burn slower and longer or faster and shorter.
As you might imagine, it's vastly less complicated than a liquid motor that has pumps and tanks and lines and computers and software and a precise need to meter fuel ratios.
The other thing that struck me - the rocket was nearly binary; it was off, then it was on (and gone
The bat-out-of-hell take off of Vega is not a function of the release mechanism. Like @Grendal said, a liquid motor gets run up to some steady state operating parameters before release. Among other things, before you let go of the launcher you have an opportunity to abort and save the mission. It's also possible to more precisely control the thrust profile to manage mission specific parameters/loads (to maximize efficiency of the mission), so the moment of take off may not necessarily be maximum thrust like it basically is with a solid.
Vega is roughly in the same market as the old Falcon 1e. I thought it was a pity that SpaceX didn't keep their hand in that market.
Agree. Unfortunately, profit margin with rockets, like cars, leads a manufacturer to want to sell bigger, more expensive vehicles. They're all going for the S class of launchers, so to speak.
There's a developing market for smaller dedicated launchers (instead of aggregating small, unrelated missions on a single rocket), but until someone can make the Honda Civic of launchers, the game is to go big. And bigger, as it were...falcon heavy, new Glenn, etc.
It's tough to read the tea leaves, but Rocket lab is probably the closest to a small launcher. Fingers crossed!
There's a developing market for smaller dedicated launchers (instead of aggregating small, unrelated missions on a single rocket), but until someone can make the Honda Civic of launchers, the game is to go big. And bigger, as it were...falcon heavy, new Glenn, etc.
It's tough to read the tea leaves, but Rocket lab is probably the closest to a small launcher. Fingers crossed!
