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Agree. The dangerous part for the shuttle is not the landing part but the getting there part. It would have been mostly if not exclusively a series of 'passive' control surface maneuvers to turn the orbiter back toward Florida and then burn off altitude. The powered solution SpaceX uses is much more controllable.
e-FTW
New electron smell
I've always loved that quote, ever since I fell in a massive rat hole reading up on Shuttle abort modes. All of them...
adiggs
Well-Known Member
Mike1080i
Member
As I recall the shuttle RTLS was an active maneuver called the Powered Pitch-Around (PPA). The Orbiter/ET stack would pitch over with the SSME's and continue the burn, thrusting back toward the landing site until it had enough energy to reach the landing site and the ET had 2% or less propellant remaining. I believe Captain Young made the right call.
Section 6.2 RTLS Overview and Figure 6-1 Typical RTLS profile
https://www.nasa.gov/centers/johnson/pdf/383447main_intact_ascent_aborts_workbook_21002.pdf
And why do you think that?
I’m anxious to know the launch time. It will make a difference in how I plan my trip to see the launch.
It is, or at least has been RTLS. There's talk of it being expended due to range conflicts.
That would be a nutty thing to do. For lots of reasons as far as SpaceX is concerned. Worst case is make it an ASDS landing even though it could be a RTLS. SpaceX needs to recover this booster to examine it.
Thanks, had just checked my spaceXnow app and saw that time and was about to post it.
I voice dictated this post had to correct it: spaceXnow came out as “ space sex now”.
Pardon my ignorance on Orbital mechanics - are orbits named after what time it is launched? Is there a correlation to when something is launched to which orbit it will end up with?
Disclaimer: The following is pure speculation based on publicly available information.
So, yeah, dumping the core kind of stupid. But...there's a super-duper secret payload on base (or at least will be on base?) ready to ride the DH at the end of the month, and The Man is probably paranoid that somehow SpaceX is going to bomb the NRO processing facility with their returning first stage.
(Bomb = an accident, not a nefarious act, just to make sure we're all on the same page.
) Anyway, assuming the barge is ready and available (and I'm sure SpaceX could/would do whatever they need to make it ready), there's also filings that are required...and its possible its too late for them...?
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I think SpaceX would rather delay the launch than throw away a block V if it didn’t need to based on mission requirements.Disclaimer: The following is pure speculation based on publicly available information.
So, yeah, dumping the core kind of stupid. But...there's a super-duper secret payload on base (or at least will be on base?) ready to ride the DH at the end of the month, and The Man is probably paranoid that somehow SpaceX is going to bomb the NRO processing facility with their returning first stage.
(Bomb = an accident, not a nefarious act, just to make sure we're all on the same page.
Anyway, assuming the barge is ready and available (and I'm sure SpaceX could/would do whatever they need to make it ready), there's also filings that are required...and its possible its too late for them...?
Sorry, yeah, there's a couple things going on with my cryptic response.
Short story is that sun synchronous orbits (SSO), which are top-to-bottom orbits around the earth, are referred to by times. Those times, as a result of orbital physics (not just random coincidence), are often very close to the local time of launch.
Longer story, the whole point of an SSO is that you want to fly over the same part of the earth every orbit--but specifically the same part relative to the sun, NOT relative to whatever land/sea mass is under you. There's a whole lot of Maths behind it and there are plenty of reasons why this isn't completely true, but at least for the sake of visualization, what that means is that every time you cross the equator you do so at basically the same local earth time.
To make that visualization easier, when you look down on earth's orbit relative to the sun you'll always see a dark half and a light half of the earth, with the separation between the two being the dawn/dusk horizons. If you call those horizons 6am and 6pm, then imagine a satellite orbiting the earth that has a ground track that traces that horizon line, you're imagining a 6am/6pm SSO orbit. Mark the point on the sunny side of the earth directly facing the sun as 'noon', and you can visualize the rest of the earth's disk filling out the hours on a clock face.
In the case of SSO-A (this is Spaceflight's first Falcon launch into SSO...clever bunch of aerospace people on identifying the launch...) it’s a 10:30am orbit, which means that every time the satellite crosses the equator on the sunny side of the earth, it does so at 10:30am. Doesn’t matter if it’s over South America, Africa, the Indian Ocean, etc...it’s always 10:30am. (On the "Dark side" of the earth it flips 12 hours so you actually cross the equator at 1030pm). 1030 isn's just a random orbit either, its quite preferred for earth observation: The sun angle on the earth is high enough that you can get good images of whatever you're shooting throughout all the seasons, but 1030 is early enough in the local day (wherever you're imaging) that you statistically minimize cloud cover, since most places on the globe stir up weather/clouds in the afternoon where the local temperature is the warmest.
Fast forward a bit and, save for some variables like the fact that you need to accelerate from zero to orbital velocity (and the fact that at liftoff you actually have "sideways" velocity because the earth is spinning), the local time at launch ends up usually being pretty close to the SSO orbit.
What that all racks up to is a 10:32am launch for SSO-A.
In the most pragmatic way possible, who cares what spaceX thinks? The launch isn't SpaceX's, it is the customer's.
Certainly we're breaking new ground in the way the rocket industry operates and I could see things changing as time moves on, but short of contractural clauses that permit spaceX to delay a launch because they don't want to lose money on dumping a core, its simply not their call.
Its like a hospital suggesting a pregnant woman move her date by a week because the delivery room is performing unscheduled repair.
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