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

[mlindner]

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?

Wrong forum topic, but welcome to the forum. That was from the CASSIOPE launch last month. This was already discussed there as well. Look further back in this forum section for those topics.

It sounds like you're trying to say its actually a UFO. That's heavily frowned upon here.

As to your questions:
Possibly stars, hard to tell. Other options are aircraft in the line of sight of the camera or other pieces of ice or small debris. The launch generated a large number of other NORAD tracked objects, those could be those.

If stars then atmospheric effects and camera jiggle could could occlude them. Could also be viewing the camera image through clouds. If not stars then as the debris spin they will reflect light in different directions causing them to flash.

Rocket fuel can form a near circle if it vents slowly. It expands outward in a sphere as any expanding gas would. Also if the jet is aiming roughly toward the viewer then you're looking at a cone end-on giving the appearance of a circle as well.

Big dot in the circle is probably the vehicle itself or denser gas near the vehicle.

[edkyle99]

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.

The true operational price and cost of such missions over the longer term remains to be seen.  It could be that one company ate more of its development costs than the other. 

One of these rockets weighs more than 500 tonnes, the other less than 300 tonnes.  I think that will show up in prices over time.

 - Ed Kyle

[mlindner]

One of these rockets weighs more than 500 tonnes, the other less than 300 tonnes.  I think that will show up in prices over time.

One of these rockets is from a huge list of subcontractors with further subcontractors with no future prospects for cheaper cost, the other is mostly built in house leaving open the possibility of increases in efficiency of construction. I think that will show up in prices over time.

[Chris Bergin]

This gets back on topic from this post onwards or the post will be removed.

[Zed_Noir]

Is the RCS use for attitude control of the 1st stage after staging are Draco thrusters or cold gas thrusters?

[cambrianera]

Is the RCS use for attitude control of the 1st stage after staging are Draco thrusters or cold gas thrusters?

Cold gas thrusters (see pic)

[jcm]

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.

Unlikely. This has all the hallmarks of an intermediate orbit by the payload - would be fairly typical, you'd expect
a series of apogee burns to raise perigee to GEO while lowering inclination, then lower apogee back down to GEO.

[jcm]

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

err...  "U" just means 'Unclassified'.  All the objects on the public spacetrack site are tagged  U.

But you're right that NORAD/JSPOC hasn't named the objects yet, and I agree that 39460 is the Falcon stage and 39461 the payload - for now. Expect the TLEs to swap around when JSPOC spots this.

[cleonard]

Is there an estimation of the orbit lifetime for the second stage?  Without perturbations it would be a very long lifetime with a 400km perigee.  When you add in the effect of the sun and moon there will be oscillations of the eccentricity.  This is one of the largest effects for a typical GTO orbit and the magnitude will be even larger for this super GTO.

Is there any released expectation of how long the second stage will stay in orbit?

[Avron]

Is there an estimation of the orbit lifetime for the second stage?  Without perturbations it would be a very long lifetime with a 400km perigee.  When you add in the effect of the sun and moon there will be oscillations of the eccentricity.  This is one of the largest effects for a typical GTO orbit and the magnitude will be even larger for this super GTO.

Is there any released expectation of how long the second stage will stay in orbit?

QuantumG did a calc a few days back.. cant find the post.. if my memory is correct - reentry around 3-4 th month 2014

[llanitedave]

I thought that was using a lower perigee.

[Jim]

Correct.  The CCAM must have raised the perigee

[cuddihy]

why would that be? isn't the whole point of a contamination & collision avoidance maneuver CCAM to lower perigee and de-orbit the stage sooner?

[Jim]

why would that be? isn't the whole point of a contamination & collision avoidance maneuver CCAM to lower perigee and de-orbit the stage sooner?

no, it is to keep the stage from hitting or contaminating the payload.  The depletion burn is to inert the stage.  An uncontrolled deorbit is not desired (due to risks involved) and hence operators put stages in orbits that are more than 25 years in duration

[AJA]

why would that be? isn't the whole point of a contamination & collision avoidance maneuver CCAM to lower perigee and de-orbit the stage sooner?

no, it is to keep the stage from hitting or contaminating the payload.  The depletion burn is to inert the stage.  An uncontrolled deorbit is not desired (due to risks involved) and hence operators put stages in orbits that are more than 25 years in duration

Wait. How does that help with respect to a controlled de-orbit? It's still coming down all by itself... we may have well gotten more precise at doing DAMs, tracking, predicting re-entry periods, and ellipses in 25 years time, but we're still not controlling this spent stage.

Why wouldn't you burn to depletion in a way that lowers the perigee as much as possible? That would also function as a CCAM. Pushing it higher is only going to return you to the current pre-CCAM situation some X years down the line. Sure, YOUR payload's (launched by that spent stage) operational life might've been over by then, but that orbital slot is hardly going to be vacant... (even if it's not a new satellite, your own dead satellite might be in the same spot... it was using its prop to prevent decay for Y years, it would've started decaying later..)

[Avron]

Talking stats, I notice that the latest Proton launch with Inmarsat 5 F1  weights in at 13,448 pounds,, more that twice that of SES-8.. Made by Boeing vs Orbital, however, the Inmarsat 5 is for broadband vs coms for SES. Was wondering If the F9H could do the launch job for an Inmarsat or two SES sized sats

[Ben the Space Brit]

I think that SpaceX is planning to use FH for their Intelsat contract.

[Jim]

Wait. How does that help with respect to a controlled de-orbit? It's still coming down all by itself... we may have well gotten more precise at doing DAMs, tracking, predicting re-entry periods, and ellipses in 25 years time, but we're still not controlling this spent stage.

Why wouldn't you burn to depletion in a way that lowers the perigee as much as possible? That would also function as a CCAM. Pushing it higher is only going to return you to the current pre-CCAM situation some X years down the line. Sure, YOUR payload's (launched by that spent stage) operational life might've been over by then, but that orbital slot is hardly going to be vacant... (even if it's not a new satellite, your own dead satellite might be in the same spot... it was using its prop to prevent decay for Y years, it would've started decaying later..)

It doesn't.  This is SOP for upperstages (except the couple that have a known massive excess margin).  It is an insurance and liability issue.  There is no propellant for a controlled deorbit in GTO missions.  The stages have limited life and usually are dead before reaching apogee for a deorbit burn.  Also, it might be a bad point to do the entry at that time.

CCAM is not done with the main engine, it is done with thrusters.  The depletion or inerting "burn" is not even a burn, it is just a dump of the propellants.

[LouScheffer]

why would that be? isn't the whole point of a contamination & collision avoidance maneuver CCAM to lower perigee and de-orbit the stage sooner?

no, it is to keep the stage from hitting or contaminating the payload.  The depletion burn is to inert the stage.  An uncontrolled deorbit is not desired (due to risks involved) and hence operators put stages in orbits that are more than 25 years in duration

I believe this is backwards.  The requirement is that the stage MUST re-enter within 25 years, unless it's placed into an orbit that poses no risk of collision:

Launcher stages shall satisfy one of the following conditions:

a) they shall perform a direct reentry as part of the launcher sequence;

b) they shall be placed in a LEO orbit where they will re-enter the Earth’s atmosphere within 25 years;

c) they shall be permanently removed from the LEO and GEO protected regions, and from orbits interfering with other operational orbit regions, such as the Galileo orbit.

From "Compliance of Rocket Upper Stages in GTO with Space Debris Mitigation Guidelines", http://www.spacesafetymagazine.com/2013/07/18/compliance-rocket-upper-stage-gto-space-debris-mitigation-guidelines/

Also, uncontrolled entry is allowed, and normally used, unless the risk is too big

6.2.3 Reentry
OR-06

For space systems that are disposed of by reentry, the prime contractor shall perform an analysis to determine the characteristics of fragments surviving to ground impact, and assess the total casualty risk to the population on ground assuming an uncontrolled reentry.

OR-07

In case the total casualty risk is larger than 10-4, uncontrolled reentry is not allowed. Instead, a controlled reentry must be performed such that the impact foot-print can be ensured over an ocean area, with sufficient clearance of landmasses and traffic routes.

[prime8]

Pushing it higher is only going to return you to the current pre-CCAM situation some X years down the line.

Don't forget that the higher push is from the GTO, not GEO. GEO is in a different plane from GTO, meaning that the mechanics of a collision will be much different after the payload maneuvers to its operational location.