Author Topic: Falcon 9 v1.1 - ABS-3A/Eutelsat 115 West B - March 1, 2015 - DISCUSSION  (Read 230997 times)

Offline zubenelgenubi

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One month after launch, Eutelsat is at 3,072 x 61,868 km x 19.36 deg.  ABS 3A is at 1,139 x 64,561 km x 17.54 deg.  Interesting that the two satellites appear to be using different ascent profiles at this point, with ABS 3A focusing more on inclination reduction.

 - Ed Kyle
Could this be deliberate attempt at gaining as much experience about electric drive as possible?

Maybe Boeing, with the owners'/operators' permission, is testing two separate GTO to GEO mission profiles?
If no one has ever used "all-electric" to perform this before, maybe there are open questions about the details of how to best accomplish it?

"Best" might be different for differing payloads or requirements?
(I know best is a subjective term.)

A thought,
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Offline Joffan

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One month after launch, Eutelsat is at 3,072 x 61,868 km x 19.36 deg.  ABS 3A is at 1,139 x 64,561 km x 17.54 deg.  Interesting that the two satellites appear to be using different ascent profiles at this point, with ABS 3A focusing more on inclination reduction.

 - Ed Kyle

Could this be deliberate attempt at gaining as much experience about electric drive as possible?

Or maybe they're trying to manoeuvre the two satellites apart as soon as possible. Why? Maybe to avoid possible mutual interference due to RCS plumes.

That said, how far apart are ABS-3A and Eutelsat-115WB's target orbital slots?

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Offline Comga

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Quote from: Douglas Adams
Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.
The satellites are in no danger of affecting each other.
Very much so, and a wonderful quote.  I can hear the British accent of the original BBC radio comedy just reading this.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline edkyle99

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As of April 16, 2015
Falcon 9 second stage:   370 x 63,359 km x 25.32 deg
Eutelsat 115 West B:   3,322 x 64,258 km x 14.24 deg
ABS 3A:                       4,273 x 64,666 km x 12.43 deg

 - Ed Kyle

Offline Tonioroffo

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Quote
Falcon 9 second stage:   370 x 63,359 km x 25.32 deg

What is the reason the 2nd stage is still out there?  Does it take that long to deorbit?

Offline SwissCheese

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Falcon 9 second stage:   370 x 63,359 km x 25.32 deg

What is the reason the 2nd stage is still out there?  Does it take that long to deorbit?

The perigee is rather high at 370 km, where the drag is quite low, and only happens during a short part of the orbit, so yes it will take a long time to deorbit.

This high perigee was probably chosen because of the electric propulsion used by the satellites launched: since the electric propulsion is raising their orbit rather slowly, they would have experienced a lot of drag using a usual perigee altitude for GTO launches (~185 km).

There are software available, where you can estimate the decay of satellites, but you have to know several parameters of the object (such as shape, weight, ...). Maybe someone here can give an estimation?


Offline eriblo

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Quote
Falcon 9 second stage:   370 x 63,359 km x 25.32 deg

What is the reason the 2nd stage is still out there?  Does it take that long to deorbit?

The perigee is rather high at 370 km, where the drag is quite low, and only happens during a short part of the orbit, so yes it will take a long time to deorbit.

This high perigee was probably chosen because of the electric propulsion used by the satellites launched: since the electric propulsion is raising their orbit rather slowly, they would have experienced a lot of drag using a usual perigee altitude for GTO launches (~185 km).

There are software available, where you can estimate the decay of satellites, but you have to know several parameters of the object (such as shape, weight, ...). Maybe someone here can give an estimation?

Not an expert but a comparison: the ISS used to orbit lower than that (~350 km, constantly) and only lost about 2-3 km in altitude per month, despite the huge solar panels. You need to get lower before the drag becomes significant.

Offline kevin-rf

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If you look at Ed's 3/15 post you will see that the second stage was in 366 x 63,372 km x 25.03 deg orbit.
32 days later it is in a 370 x 63,359 km x 25.32 deg orbit.

So the apogee has dropped 13 km in 32 days, or a little under half a km a day (ignoring any lunar effects, notice the perigee went from 366 to 370 km). The average orbital altitude dropped only 8km or 1/4 km a day.

Really bad math say it will be up for the at least the next 80ish years give or take a few decades.
« Last Edit: 04/17/2015 01:17 PM by kevin-rf »
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Online LouScheffer

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Quote
Falcon 9 second stage:   370 x 63,359 km x 25.32 deg

What is the reason the 2nd stage is still out there?  Does it take that long to deorbit?
The rule is that you are supposed to leave the stage in an orbit that will decay in less than 25 years, so it does not remain a long-term hazard.  If I recall correctly, that means less than a (roughly)  400 km perigee for GTO orbits and typical second stage drag numbers.   The current perigee is not much less than 400 and so the stage may well be up there for another decade or so.

Offline zubenelgenubi

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Quote
Falcon 9 second stage:   370 x 63,359 km x 25.32 deg

What is the reason the 2nd stage is still out there?  Does it take that long to deorbit?
The rule is that you are supposed to leave the stage in an orbit that will decay in less than 25 years, so it does not remain a long-term hazard.  If I recall correctly, that means less than a (roughly)  400 km perigee for GTO orbits and typical second stage drag numbers.   The current perigee is not much less than 400 and so the stage may well be up there for another decade or so.

The amateur satellite-trackers will like the addition of another item to their observing lists?
Checking Heavens-above http://www.heavens-above.com/, I see only 5 Falcon 9 2nd stages still orbiting:
Dragon C1,
CASSIOPE,
AsiaSat 8,
DSCOVR,
and this flight's.
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Offline Tonioroffo

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Thanks all, for clearing that up.
« Last Edit: 04/18/2015 03:49 PM by Tonioroffo »

Offline edkyle99

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As of May 12, 2015
Falcon 9 second stage:   386 x 63,327 km x 25.55 deg
Eutelsat 115 West B:   6,635 x 62,713 x 8.64 deg
ABS 3A:                       8,262 x 62,508 km x 7.16 deg

 - Ed Kyle

Offline Comga

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As of March 15, 2015
ABS 3A:   449 x  63,530 km x 24.99 deg
Eutelsat 115 WB:  439 x 63,363 km x 24.99 deg
Falcon 9 Stg 2:  366 x 63,372 km x 25.03 deg

 - Ed Kyle

As of May 12, 2015
Falcon 9 second stage:   386 x 63,327 km x 25.55 deg
Eutelsat 115 West B:   6,635 x 62,713 x 8.64 deg
ABS 3A:                       8,262 x 62,508 km x 7.16 deg

 - Ed Kyle

So in 65 days the apogee of the second stage has come down by only 45 km?
And the perigee is going up, decreasing the drag through the exosphere by about a factor of two.
This stage could be up there for a very long time.
Are there any predictions of orbital lifetime for spent stages in GTO?



But the satellites are making nice progress towards GSO.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Scylla

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Boeing: World’s First All-Electric Propulsion Satellite Begins Operations
http://boeing.mediaroom.com/2015-09-10-Boeing-World-s-First-All-Electric-Propulsion-Satellite-Begins-Operations

EL SEGUNDO, Calif., Sept. 10, 2015 – The world’s first all-electric propulsion satellite, built by Boeing [NYSE: BA] for Bermuda-based ABS, is now operational after an on-orbit handover on August 31. The ABS-3A, a 702SP (small platform) satellite, expands ABS’ communications services in the Americas, Europe, the Middle East and Africa.

“The operational ABS-3A satellite and ABS-2A, launching in early 2016, will further strengthen and solidify our global expansion and offer flexible capacity to our growing fleet,” said Tom Choi, CEO of ABS. “We believe Boeing’s innovative portfolio can help us to affordably grow now and in the future.”

The ABS-3A spacecraft was the world’s first all-electric propulsion satellite to be built and launched – part of a stacked pair launched in March with a 702SP satellite built for Eutelsat, based in Paris. The spacecraft’s all-electric xenon-ion propulsion system contains a sufficient quantity of the inert, non-hazardous element xenon to extend the satellite’s operations beyond the expected spacecraft design life of 15 years.

“With a successful launch, testing and execution of orbit operations, we were able to deliver the first 702SP to ABS about one month earlier than planned,” said Mark Spiwak, president, Boeing Satellite Systems International. “The 702SP product line was designed to bring the latest technology into the hands of customers seeking adaptable and affordable solutions. In addition, the 702SP’s patented dual-launch capability helps customers share launch costs, which can significantly lower overall expenses for a satellite owner.”

Boeing is under contract to build a second 702SP satellite for ABS, designated ABS-2A, which will be delivered and launched early next year.

A unit of The Boeing Company, Defense, Space & Security is one of the world's largest defense, space and security businesses specializing in innovative and capabilities-driven customer solutions, and the world’s largest and most versatile manufacturer of military aircraft. Headquartered in St. Louis, Defense, Space & Security is a $31 billion business with 53,000 employees worldwide. Follow us on Twitter: @BoeingDefense.
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