SpaceX F9 - 17th Reuse - Es’hail-2 - LC-39A

[Grendal]

Launch Date: November 15
Launch Window: 2046-2227 GMT (3:46-5:27 p.m. EST)
Launch site: LC-39A, Cape Canaveral, Florida
Booster Recovery: ASDS - OCISLY
Booster Type: B1047.2 - Reused from Telstar 19V
Mass: 3000 kg
Orbit: GTO

A SpaceX Falcon 9 rocket will launch the Es’hail 2 communications satellite. Built by Mitsubishi Electric Corp. and owned by Qatar’s national satellite communications company Es’hailSat, Es’hail 2 will provide television broadcasts, broadband connectivity and government services to Qatar and neighboring parts of the Middle East, North Africa and Europe. Es’hail 2 also carries the first amateur radio payload to fly in geostationary orbit.

Es'hail 2
Es’hail 2

18th SpaceX launch of the year.
7th drone ship landing of the year.
If successful, this will be the 31st recovered booster.
There have been 8 new boosters used and 9 reused boosters flown this year.

 

[Grendal]

One day slip. Static fire expected to happen on 11/11. Now 11/12

 

[e-FTW]

Static fire complete. Onwards!
SpaceX on Twitter

 

[Grendal]

Weather is not great. 60% go for launch.

 

[Grendal]

Webcast for Es'Hail-2:

 

[Grendal]

Another successful launch and landing.

 

[Zaxxon]

Now a long turn-around until... *checks calendar* Monday? ...for a *checks details* twice-used F9?

 

[Electroman]

I have watched all the launches and landings, mostly live, and it never gets boring..

 

[Grendal]

JMHO but this launch had some of the most beautiful visual moments. Maybe a better on board camera? Stunning.

 

[e-FTW]

For this launch, I looked at the displayed speed during a few phases of flight. And I was blown away by the acceleration differences.

At first, right after launch, you can pretty easily follow the second digit (the tens).
As the stage passes through MAX-Q and leaves the thicker part of the atmosphere, while at the same time getting lighter, you quickly cannot follow along and you start seeing the hundreds tick by fast, getting to about one per second by MECO.
That is an extra 100 km/h (60 mph) per second! That blows my mind when I think about what those things can do.

The kicker: when the second stage starts its first burn, it starts accelerating about as fast as the first stage was doing after MAX-Q, but keeps going to where it blows the doors off of stage 1 on its first burn. By the end of the second burn, the thousands are going by at a rate of almost one per second.
It accrues an extra “speed of sound” in about a second!
[Ok, maybe 500 km/h, not a full thousand per second. But still!]

I know I am probably making some physics majors grind their teeth at my wild comparisons and eye-ball physics. But I get excited by this stuff, even though I don't speak orbital mechanics.

 

[e-FTW]

Also, what's with the apparent tumbling of the satellite post-release?
I've never noticed that before. Am sure it can take care of that with gyros and propulsion. Still seems odd.

 

[bxr140]

Also, what's with the apparent tumbling of the satellite post-release?
I've never noticed that before.

Some manufacturers like to do that. They have the separation system springs configured assymetrically around the circumference of the separation interface, either with more springs or longer throw springs on one ‘side’ of the circumference. (I don’t think different spring rates are ever used, but who knows?) When the clamp releases and all the springs push the satellite away, the result is a force vector not coaxial with the upper stage...and so the satellite is ejected with some ‘tumble’ rate relative to the upper stage. (Thanks to Newton’s ‘equal and opposite’ the upper stage tumbles in the opposite direction, so the rate you see in a separation video is significantly larger than the satellite’s rate relative to the earth)

The reason they do that is because there are usually nulls in the telemetry and command antennae coverages. Usually there’s a redundant set pointed toward earth, which is the wrong direction in GTO, and then usually there’s a redundant set on the ‘back’ of the spacecraft, pointed a little bit to the side...which is the right direction-ish while in GTO. The coverages are quite wide but not a whole sphere. By tumbling, you minimize the likelihood that a wayward upper stage is going to put you into an attitude [in GTO] where earth is in a null and you can’t talk to your satellite.

Talking to a satellite ASAP is quite preferred, because basically the first thing you do after acquisition is pop the solar arrays so you can start making power. Batteries don’t last forever...

And, yes, satellites have automatic recovery modes to initiate a tumble in the event commanding is lost, but the simple menchanical solution of assy metric separation means you’re very unlikely to need that fault mode right after separation.

And also yes, technology has evolved to a point where forcing a rate on separation isn’t really necessary, but some ever paranoid space people don’t want to change a solution that isn’t broken...

 

[Electroman]

yet another datapoint as to why this is my favorite sub-forum in TMC.