SpaceX to push the envelope on 3rd Starship test flight

[Admin]

SpaceX will put its Starship megarocket through its paces on its third test flight, which could launch as soon as next week.

SpaceX to push the envelope on 3rd Starship test flight : Read more

 

[jan.wolitzky]

So, again, a suborbital flight, even shorter than the mission planned for the previous tests. I like the term "water landing" to describe dumping both booster and Starship in the ocean. Like calling a car crash "tree parking".

 

[danR]

So, again, a suborbital flight, even shorter than the mission planned for the previous tests. I like the term "water landing" to describe dumping both booster and Starship in the ocean. Like calling a car crash "tree parking".

The more common term is "ocean landing". https://www.faa.gov/media/72816
There are two different water landings. The booster won't crash; it's termed a "soft water landing": sea level is treated a proxy for land-surface (and ultimately as a sea-platform surface; for most missions, ultimately, will not be land-based) and they will attempt to bring the vehicle to a near-zero velocity, let it sink in whereupon it will topple over/sink across the entire structure.

Starship proper will reenter off Hawaii and will contact the water lengthwise at terminal velocity. But most people would immediately picture a car crashing in a head-on configuration. Starship won't land head-on, but at a terminal velocity of ~85 m/s (estimates vary) it could most fairly be called a "belly-flop".

 

[jan.wolitzky]

"Water landing" is the term SpaceX uses in their own description of the mission (<https://www.spacex.com/launches/mission/?missionId=starship-flight-3>). And they say that Starship will "land" in the Indian Ocean, not off Hawaii. 85 m/s is 190 mph, well over the terminal velocity of a human falling without a parachute, more of a severe crash than a "belly flop".

 

[CommonSenseNow]

"Push the envelope"....what does that mean? A bigger explosion when they blow the thing the hell up again?!?

 

[Torbjorn Larsson]

This is exciting!

"Water landing" is the term SpaceX uses in their own description of the mission (<https://www.spacex.com/launches/mission/?missionId=starship-flight-3>). And they say that Starship will "land" in the Indian Ocean, not off Hawaii. 85 m/s is 190 mph, well over the terminal velocity of a human falling without a parachute, more of a severe crash than a "belly flop".

SpaceX has a new flight trajectory and landing details compared to the 2nd test flight: https://www.spacex.com/launches/mission/?missionId=starship-flight-3 The booster will perform a landing burn so will simulate later landings at the catch tower (it has no legs).

The Starship seems destined to repeat the belly landing (no landing burn declared, the image shows the same belly landing) at terminal speed. Terminal speed for Starship is estimated from early versions to be around 80 m/s, which is about 300 km/h or race car crash speeds.

If they can do a first ever fuel transfer in space they satisfy NASA Artemis immediate concerns and if they can open the cargo doors they satisfy their Starlink V2 immediate concerns. (V2 will enable cheaper Starlink systems but can't be launched with the smaller Falcon 9.)

Reusing Starships by repeating the landing demos are further up the line, reusing boosters are much more of an immediate concern in terms of cost and production time (an order of magnitude more engines).

"Push the envelope"....what does that mean?

Trying to achieve more objectives:

The third flight test aims to build on what we’ve learned from previous flights while attempting a number of ambitious objectives, including the successful ascent burn of both stages, opening and closing Starship’s payload door, a propellant transfer demonstration during the upper stage’s coast phase, the first ever re-light of a Raptor engine while in space, and a controlled reentry of Starship. It will also fly a new trajectory, with Starship targeted to splashdown in the Indian Ocean. This new flight path enables us to attempt new techniques like in-space engine burns while maximizing public safety.

 

[Unclear Engineer]

I think that this new flight plan tasks seem like a good way to gain more data to rapidly improve the two vehicles, given their current states of development.

However, adding more tasks that have never been attempted before is creating a high probability that some of them will fail. That doesn't seem to bother SpaceX, and I don't think it should.

But, it does seem to be a problem with the FAA culture, which seems to be more along the lines of everything must go exactly as planned and be successful or it requires the government to "review" the "causes" of the "failures".

I think that these FAA reviews need to be limited to unforeseen events that could cause unforeseen safety issues. There seems to be a significant difference between Musk's prelaunch admission that the first test flight might blow up on the ground and FAA being concerned that it was intentionally blown up well down the test range without getting out of bounds. I do agree that the FAA needed to review the lag in the response to the signal to detonate the safety explosive charge in the first flight. But, why the first flight needed to be terminated really doesn't seem like it should be FAAs issue for a test flight where failure at some point is known to have a high probability, going in.

The second flight did not seem to produce anything that the FAA really needed to review for safety reasons, so far as I have heard.

Regarding the plan for Starship to do a belly-flop landing in the Indian Ocean, instead of a simulated soft landing, I am wondering if the concern about potential salvage by China has anything to do with the chosen impact velocity.

 

[PatsyG]

Sub-orbital is an understatement