SpaceX Starship : First Flight : Starbase, TX : 20 April 2023 - DISCUSSION

[Alexphysics]

Those FCC permits have a standard 6 month duration (there are other standard durations but basically the end date is not chosen). SpaceX can choose only the start of it and when gongora said it was NET than that back in December it was mostly because that was the earliest that at that moment they could launch and be able to use that permit not that it would launch on January 20th.

[FutureSpaceTourist]

https://twitter.com/elonmusk/status/1621998434289942529

If remaining tests go well, we will attempt a Starship launch next month

[FutureSpaceTourist]

Confirmation of expected thrust for this launch, about 90% (where the static fire on Thursday was bit less than 50%):

https://twitter.com/elonmusk/status/1624412830446534656

This test is at ~50% throttle. Launch attempt next month will be at ~90%.

P.S. To state the obvious, Elon still talking about next month suggests SpaceX are happy with the static fire (or at least not expecting any significant delays arising from the static fire)

[FutureSpaceTourist]

https://twitter.com/rocketrick/status/1625115510508773376

Hmnnnn…
March 11?

https://wccftech.com/spacex-starship-launch-date-potentially-revealed-in-nasa-calendar/

Very much a NET date I assume (from NASA's WB-57 calendar)

Edit to add: consistent with Elon yesterday (so still Elon time?)

https://twitter.com/elonmusk/status/1624898503267983360

Starship orbital launch attempt soon!

[Orbiter]

https://twitter.com/rocketrick/status/1625115510508773376

Hmnnnn…
March 11?

https://wccftech.com/spacex-starship-launch-date-potentially-revealed-in-nasa-calendar/

Very much a NET date I assume (from NASA's WB-57 calendar)

I wouldn't read too much into it, those dates also have Crew-6 launching on the 18th (when it's the 26th) and are likely out-of-date.

[Alexphysics]

Yes that date has been there for well over two weeks by now and several other dates are wrong as indicated above.

[GewoonLukas_]

Yes that date has been there for well over two weeks by now and several other dates are wrong as indicated above.

It also says "placeholder"

[alugobi]

On the launch pad, they are assembling very heavy panels that will be affixed to the top of and all around the OLM, covering the open space where all the pumps, conduits, electrical boxes, etc.  That's a lot of welding, big stuff like when they build the launch mount. 

They're also digging out concrete outside the blast area directly below the engines, on the back side if looking at it from the tank farm.  This might be only surface replacement after the static fire, or it might be trenching out for water lines coming from the new deluge system being installed. 

Figure that into a launch date. 

[PM3]

Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?

[daedalus1]

Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?

Technically it's not going to be below orbital velocity,  it's just that the low point of the orbit is within the upper atmosphere .

[PM3]

Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?

Technically it's not going to be below orbital velocity,  it's just that the low point of the orbit is within the upper atmosphere .

So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?

[Edit: corrected typos in video title]

[daedalus1]

Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?

Technically it's not going to be below orbital velocity,  it's just that the low point of the orbit is within the upper atmosphere .

So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explanes updated to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?

Haven't seen the video,  but that is only 67 mph which would mean the low point of the orbit will dip into the atmosphere.

[eriblo]

Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?

Technically it's not going to be below orbital velocity,  it's just that the low point of the orbit is within the upper atmosphere .

So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explanes updated to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?

Haven't seen the video,  but that is only 67 mph which would mean the low point of the orbit will dip into the atmosphere.

There is no updated information regarding the trajectory and the logic behind it remains the same.

The 30 m/s number is the difference between the assumed perigee inside the atmosphere and one that would clear it with some resonable guess for the apogee (we do not know exactly what they plan).

The absolutely lowest orbit that can do this trajectory will have an extremely shallow reentry angle which means that you might miss the landing with 1000s of km if you miss the engine shutdown by a fraction of a second or have the wrong thermosphere density numbers.

Increasing the apogee steepens the reentry angle and gives more margin while reducing the difference with regard to the lowest possible circular orbit.

Depending on the trajectory chosen there might be a lower energy circular orbit that would make it around at least once.

[Hog]

For comparison regarding orbital underspeeds.
STS-93-Columbia launched and reached orbit carrying the heaviest payload carried by STS . the CHANDRA telescope and its Inertial Upper Stage weighed 22,780kg/50,222lbs, OV-101 Columbia, weighed 122,534 kg/270,142 lb at liftoff. 
At main engine start a gold pin used to block the engines oxidizer post was blasted from the Main Combustion Chamber and tearing into 3 of the 1080 stainless tubes that comprise the nozzle's regenerative cooling capability. 
This leaking fuel forced that engine's #2 engine controller to increase oxidizer flow from its nominal 6.03:! O/F ratio, which then resulted in a LOX low level cutoff at MECO(Main Engine Cut Off) some 8-1/2 minutes later. This early cut off resulted in  an orbital velocity which was 15 ft/s (4.6 m/s) lower than expected. "The vehicle safely achieved its intended orbit and completed the mission as planned."
It should be noted however that if 5 of the 1080 stainless steel regenerative cooling tubes are damaged within close proximity Loss of Crew/Vehicle(LOCV) is probable.  Thankfully just 3 tubes were ruptured.

So STS-93 experienced a 15 ft/s or 4.6 m/s underspeed vs. the 30 m/s or 108 feet/second velocity for Starship
Attachments
1) pic of the STS-93 Space Shuttle Main Engines(SSME) RS-25 engines with the damage on the inside of the Right (#3) engine visible as the brighter spot along the inner wall of the nozzle.

[FutureSpaceTourist]

https://twitter.com/wapodavenport/status/1626790650921291777

From what I hear, everything is on track for a March launch attempt as far as the FAA is concerned.

[FutureSpaceTourist]

twitter.com/jeff_foust/status/1628091943241515012

Gary Henry, senior advisor for national security space solutions at SpaceX, says at a Space Mobility panel that both the Starship booster and pad are in "good shape" after static fire test earlier this month. The test was the "last box to check" before the first orbital launch.

https://twitter.com/jeff_foust/status/1628092269872947201

He adds the company still needs an FAA launch license but expects that in the "very near future." Tells the audience to expect some "must-see TV" sometime in March.

[FutureSpaceTourist]

twitter.com/nasaspaceflight/status/1628440973452759040

Starship's Orbital Test Flight milestones to launch, and the countdown by the numbers, with analysis from Adrian Beil (@BCCarCounters).

Starship's big day is *potentially* just weeks away!

https://twitter.com/nasaspaceflight/status/1628440975470108673

And here's Adrian with the overview in video form, with additional visuals:

[Comga]

Cross-post:

0421-EX-ST-2023  Starship Orbital Test Flight
Operation Start Date (NET) March 15

[Vahe231991]

From SpaceNews:
[Feb 22]

ORLANDO — SpaceX’s static-fire test of nearly all the engines in its Starship booster earlier this month was “the last box to check” before the vehicle’s first orbital launch attempt, likely some time in March, a company official said Feb. 21.

Speaking on a panel at the Space Mobility conference here about “rocket cargo” delivery, Gary Henry, senior advisor for national security space solutions at SpaceX, said both the Super Heavy booster and its launch pad were in good shape after the Feb. 9 test, clearing the way for an orbital launch that is still pending a Federal Aviation Administration launch license.

[…]

[FST edit: I deleted most of the quoted material. We can’t quote large parts of other news sites copyrighted articles.]

[FutureSpaceTourist]

https://twitter.com/rgvaerialphotos/status/1628529052695818241

Got an email “SpaceX Opens Accreditation for Starship Flight Test”

We’re getting close!