SpaceX Falcon 9 v1.1 - SES-8 - DISCUSSION THREAD

[edkyle99]

NORAD still has both classified as U, ie 39460U and 39461U, meaning they haven't sorted it out yet...

Using a crude back of envelope calculation ( Earth Dia 6371km) with the latest NORAD TLE's 39460U has a lower perigee at model dependent altitude of 397km vs. 39461U's 430km.  39461U's Apogee is also higher at 79975km.

It might be a fair to assume 39460U is the upper stage and 39461U is the payload. 

Edit: Just as a reminder Ted Molzcan excellent post on how to do the calculations http://www.satobs.org/seesat/Dec-2002/0197.html

A Dec 6 update now shows 39461U in a 14,401 x 80,416 km x 6.19 deg orbit, so Object 071B will be SES 8, gradually working its way to GEO.

 - Ed Kyle

[ugordan]

A Dec 6 update now shows 39461U in a 14,401 x 80,416 km x 6.19 deg orbit, so Object 071B will be SES 8.

Since the first reported apogee was pretty much on the money, that leaves the perigee difference from the target orbit to be explained. Any ideas?

[edkyle99]

A Dec 6 update now shows 39461U in a 14,401 x 80,416 km x 6.19 deg orbit, so Object 071B will be SES 8.

Since the first reported apogee was pretty much on the money, that leaves the perigee difference from the target orbit to be explained. Any ideas?

One possibility is that SES 8 might have made a very small perigee raising burn at first apogee.  I think that the first tracking report didn't show up until after the first orbit.

Another possibility is that the targeted orbit might have changed after the press kit was prepared.

 - Ed Kyle

[PhaseMage]

A Dec 6 update now shows 39461U in a 14,401 x 80,416 km x 6.19 deg orbit, so Object 071B will be SES 8.

Since the first reported apogee was pretty much on the money, that leaves the perigee difference from the target orbit to be explained. Any ideas?

I obviously am not an expert, but to my untrained eye this looked like SES-8 was using it's own propulsion to circularize it's orbit. Ed just said the same thing, but is it required that it was the first apogee, did the second apogee not occur before Dec 6th?

[ugordan]

One possibility is that SES 8 might have made a very small perigee raising burn at first apogee.  I think that the first tracking report didn't show up until after the first orbit.

That would be a possibility, but what would be the point in such a small burn? Checking out the propulsion?

Another possibility is that the targeted orbit might have changed after the press kit was prepared.

Perhaps. FWIW, F9 was reported to be flying under 200 km just seconds before SECO-1.

I just wish SpaceX would report the orbit they hit, even if it's just state vector the flight computer thought it had...

[Lars_J]

One possibility is that SES 8 might have made a very small perigee raising burn at first apogee.  I think that the first tracking report didn't show up until after the first orbit.

That would be a possibility, but what would be the point in such a small burn? Checking out the propulsion?

Given the low perigee, anything to raise it would seem prudent.

[ugordan]

Given the low perigee, anything to raise it would seem prudent.

295 km planned perigee is not exactly skimming the atmosphere.

[edkyle99]

One possibility is that SES 8 might have made a very small perigee raising burn at first apogee.  I think that the first tracking report didn't show up until after the first orbit.

That would be a possibility, but what would be the point in such a small burn? Checking out the propulsion?

Given the low perigee, anything to raise it would seem prudent.

A satellite suffered antenna damage from atmospheric drag a few years ago during its first perigee.  A very slight delta-v addition at first apogee, perhaps only using RCS rather than the main propulsion system, could add a bit of cushion without having to rush the orbit planning and vehicle health check processes.  Only six or seven meters per second at apogee would have added 100 km to the perigee in this case.

 - Ed Kyle

[ugordan]

A very slight delta-v addition at first apogee, perhaps only using RCS rather than the main propulsion system, could add a bit of cushion without having to rush the orbit planning and vehicle health check processes.

If that were the case, would we expect both the 2nd stage and satellite to have a perigee within of 40 km of each other, both roughly 100 km higher than in the press kit?

Would CCAM and any propellant venting be enough to account for 2nd stage apogee reduction by some 600 km and increase of perigee by 100 km?

[Danderman]

A Dec 6 update now shows 39461U in a 14,401 x 80,416 km x 6.19 deg orbit, so Object 071B will be SES 8.

Since the first reported apogee was pretty much on the money, that leaves the perigee difference from the target orbit to be explained. Any ideas?

CAM by the upper stage.

[ugordan]

In other news...... all published launch shots till now are from at least some distance away. Where are those close-up pad shots? Last time during the launch of CASSIOPE the photos came very quickly.....

Been wondering about that as well.

(and where are the photos from Ben Cooper et al.?) 

Actually, it looks like all the best ones released so far actually are Ben Cooper's work. He recently posted several on his site.

This isn't the first time some of SpaceX' official photos were taken by him. He may have some kind of an arrangement with them so that might play into the timing of his release of the photos.

[edkyle99]

In other news...... all published launch shots till now are from at least some distance away. Where are those close-up pad shots? Last time during the launch of CASSIOPE the photos came very quickly.....

Been wondering about that as well.

(and where are the photos from Ben Cooper et al.?) 

Actually, it looks like all the best ones released so far actually are Ben Cooper's work. He recently posted several on his site.

This isn't the first time some of SpaceX' official photos were taken by him. He may have some kind of an arrangement with them so that might play into the timing of his release of the photos.

Even Ben's photos look to have been taken from across the river.  I haven't seen a single pad camera image.  SpaceX isn't allowing independent press coverage, so the only images will be theirs.  If their camera setup had a bad day (gaseous oxygen clouds, lens flare, out of focus, improper camera setup, failed to trigger, etc.), there won't be any photos.  Since this was the first v1.1 launch at the Cape, there may have been unexpected effects.

I wish that a local media (or non-media) effort would take place to provide independent coverage.  If SpaceX won't allow on-site cameras, there should be multiple off site long-lens telescopes, with precise aim control and video cameras covering every second of the flights.  If that seems excessive, I would only point out that the resulting video would seem to have monetary value in the event of a failure, since SpaceX will hit its big red button and most everyone else will only have shaky, out of focus smart phone shots. 

Also, good views of these stage reentry/flyback attempts would be valuable, since SpaceX has been keeping that stuff very close to the vest.  Local media should be *very* interested in that, since these rockets are going to be flying back *toward* their towns.

 - Ed Kyle

[ugordan]

I haven't seen a single pad camera image.  SpaceX isn't allowing independent press coverage, so the only images will be theirs.  If their camera setup had a bad day (gaseous oxygen clouds, lens flare, out of focus, improper camera setup, failed to trigger, etc.), there won't be any photos.  Since this was the first v1.1 launch at the Cape, there may have been unexpected effects.

Some kind of a snafu is my guess as well.

I wish that a local media (or non-media) effort would take place to provide independent coverage.

There is some local coverage here and there. E.g. http://www.wesh.com/news/central-florida/brevard-county/SpaceX-Falcon9-rocket-launches-live-on-WESH-2-News/-/11788124/23274874/-/104rq60z/-/index.html

[edkyle99]

A very slight delta-v addition at first apogee, perhaps only using RCS rather than the main propulsion system, could add a bit of cushion without having to rush the orbit planning and vehicle health check processes.

If that were the case, would we expect both the 2nd stage and satellite to have a perigee within of 40 km of each other, both roughly 100 km higher than in the press kit?

Would CCAM and any propellant venting be enough to account for 2nd stage apogee reduction by some 600 km and increase of perigee by 100 km?

Looking back at the most recent Ariane 5, its upper stage ended up with a raised perigee and lowered apogee after its post-separation maneuvering, but the difference was smaller (tens of km each way).   I suppose the change could be bigger if the stage had more residuals and a better mass fraction than the Ariane 5 upper stage.  But the easiest explanation for the higher perigee in my mind is that SpaceX changed its plans sometime after the press kit was produced and was really aiming for that higher perigee, which represents a higher energy performance than listed in the kit.  Perhaps the change had something to do with the launch date slips.  Who knows? 

It is odd that SpaceX treated the SES 8 launch in a way that wasn't substantially more informative, in terms of orbital results, than ULA handled this morning's super top secret NRO launch!  Both webcasts were cut off long before the missions were complete, and no orbital details were provided.  I have a theory about why SpaceX is doing this, but I haven't done enough homework to know if it has merit.

There are certainly some things about this flight that the company has not revealed.  We've seen videos of the first stage doing maneuvers after separating, for example, but SpaceX has said nothing about this aspect of the flight.  Maybe Stage 2 also did some stuff we don't know about.

 - Ed Kyle

[Lars_J]

It is odd that SpaceX treated the SES 8 launch in a way that wasn't substantially more informative, in terms of orbital results, than ULA handled this morning's super top secret NRO launch!  Both webcasts were cut off long before the missions were complete, and no orbital details were provided.

 - Ed Kyle

That's rather surprising to hear from you, Ed, since you appear to put so much emphasis on the release of video 'evidence' - this flight had rocket cam footage almost to SECO1 (in addition to tracking camera footage). No such thing for the ULA launch, which only had a single tracking camera that shut off before MECO. We knew the target parking and target orbit for SpaceX, and neither for ULA.

So while I agree that the launch coverage wasn't particularly "open", I don't think the comparison is very fair.

[Canopus90]

Not sure if this is the correct forum for this topic.

Check this story:
http://www.nbcnews.com/science/ufo-o...ngs-4B11297922


Here's a video:
http://www.youtube.com/watch?v=b6CBEYht3ws


So what are these small flashing dots around the glowing object? If they are stars, why are not visible throughout the whole video but only in the middle of it and near the end? Also how did the rocket fuel formed an almost perfect circle? And finally what's that big dot inside the circle?

[Wetmelon]

I'm going to guess that the small glowing dots are either bits of insulation (very reflective) that fell off, or the payloads.  They're not visible at all times PROBABLY because of the camera's changing focus and exposure more than anything.

The gas expands to a perfect sphere because it's in microgravity    The big dot inside the circle is the second stage reflecting light.

[mlindner]

During launch there is certainly bandwidth. That is evidenced by the rapid manual switching of camera views that is done.

That is no evidence for sufficient bandwidth. That switching isn't manual, it's most likely preprogrammed on the vehicle and there is only one video stream downlinked from the stage at any given point in time. Possibly two streams in total (one for each stage), but that's it.

It sounds as if you're guessing as well, unless you have actual confirmation of the limitation.

The rapid switching for this launch was very obviously manual because of the semi-random switching. It's being selected to show the best view and give an overview to the webcast and to avoid loss of signal images. This is also of note because no two webcasts have had the same switching pattern. Also in the SpaceX montage videos released later, other camera views during the same periods of time are used so they must all have been getting downlinked.

I'm quite certain there's a human in the loop in selecting images shown to the webcast, I would also call it doubtful that ground commands are selecting these. Thus the only conclusion is they are all being downlinked.

[ChrisWilson68]

NORAD still has both classified as U, ie 39460U and 39461U, meaning they haven't sorted it out yet...

U doesn't mean "unclassified" in the sense of "we can't tell if it's a stage or a payload".  It means "unclassified" in the sense of "not secret".  You'll never see anything but a U in that field unless you have a security clearance or Snowden leaks it.

[ChrisWilson68]

The funny thing is, Orbital SSG has a lot to gain from SpaceX's success, at the grave expense of Orbital LSG.  SSG now has a cheap, increasingly reliable, domestic launcher that doesn't use 40 year old engines.  F9 fits extremely well with the size of SSG's satellites.  IMO, Antares has no more than 8 launches in its future.

Orbital's Antares won't lose any GTO business to Falcon 9 v1.1, because Antares can only lift maybe 1.5-1.8 tonnes to GTO (GEO-1800 m/s), less than half as much as the SpaceX rocket.  Antares also only lifts less than half as much to LEO.  Antares should end up costing less than Falcon 9 on a per launch basis, but that remains to be seen.  If the lower cost turns out to be true, I would expect to see both Antares and Falcon 9 at work for awhile, each working their own niche.

For CRS, each Antares flight is costing NASA much more than each Falcon 9 flight -- in fact, just 8 Antares flights are costing more than 12 Falcon 9 flights.  That includes the spacecraft and all services too, so it could theoretically be that Cygnus is just so much more expensive than Dragon it dwarfs the Antares launcher costs.  That seems quite unlikely though, especially since Dragon has reentry capability Cygnus lacks.