SpaceX Falcon 9 : Spaceflight SSO-A : December 3, 2018 - DISCUSSION

[jcliving]

If they ran a Monte Carlo simulation with at least 1000 paths, then there is a fairly robust distribution of deviations from the norm for the release.  I doubt they have projected out more than a week, but that seems to be reasonable due diligence.

[hootowls]

Thought it would be informative to provide part of US Orbital Debris Mitigation Standard Practice; ODMSP-3 & 4 in this case.  US National Space Policy requires the head of the sponsoring department or agency to approve any exceptions to ODMSP and to notify the Secretary of State.  Agencies write their requirements with this guidance in mind.

US Government Orbital Debris Mitigation Standard Practices

OBJECTIVE

3. SELECTION OF SAFE FLIGHT PROFILE AND OPERATIONAL CONFIGURATION

Programs and projects will assess and limit the probability of operating space systems becoming a source of debris by collisions with man-made objects or meteoroids.

MITIGATION STANDARD PRACTICES

3-1. Collision with large objects during orbital lifetime: In developing the design and mission profile for a spacecraft or upper stage, a program will estimate and limit the probability of collision with known objects during orbital lifetime.

3-2. Collision with small debris during mission operations: Spacecraft design will consider and, consistent with cost effectiveness, limit the probability that collisions with debris smaller than 1 cm diameter will cause loss of control to prevent post-mission disposal.

3-3. Tether systems will be uniquely analyzed for both intact and severed conditions.

OBJECTIVE

4. POSTMISSION DISPOSAL OF SPACE STRUCTURES

Programs and projects will plan for, consistent with mission requirements, cost effective disposal procedures for launch vehicle components, upper stages, spacecraft, and other payloads at the end of mission life to minimize impact on future space operations.

MITIGATION STANDARD PRACTICES

4-1. Disposal for final mission orbits: A spacecraft or upper stage may be disposed of by one of three methods:

a. Atmospheric reentry option: Leave the structure in an orbit in which, using conservative projections for solar activity, atmospheric drag will limit the lifetime to no longer than 25 years after completion of mission. If drag enhancement devices are to be used to reduce the orbit lifetime, it should be demonstrated that such devices will significantly reduce the area-time product of the system or will not cause spacecraft or large debris to fragment if a collision occurs while the system is decaying from orbit. If a space structure is to be disposed of by reentry into the Earth’s atmosphere, the risk of human casualty will be less than 1 in 10,000.

b. Maneuvering to a storage orbit: At end of life the structure may be relocated to one of the following storage regimes:

I. Between LEO and MEO: Maneuver to an orbit with perigee altitude above 2000 km and apogee altitude below 19,700 km (500 km below semi-synchronous altitude)

II. Between MEO and GEO: Maneuver to an orbit with perigee altitude above 20,700 km and apogee altitude below 35,300 km (approximately 500 km above semi-synchronous altitude and 500 km below synchronous altitude.)

III. Above GEO: Maneuver to an orbit with perigee altitude above 36,100 km (approximately 300 km above synchronous altitude)

IV. Heliocentric, Earth-escape: Maneuver to remove the structure from Earth orbit, into a heliocentric orbit.
Because of fuel gauging uncertainties near the end of mission, a program should use a maneuver strategy that reduces the risk of leaving the structure near an operational orbit regime.

c. Direct retrieval: Retrieve the structure and remove it from orbit as soon as practical after completion of mission.

4-2. Tether systems will be uniquely analyzed for both intact and severed conditions when performing trade-offs between alternative disposal strategies.

[AstroBrewer]

Sorry if  this has already been answered somewhere, but what are the target orbit parameters for SSO-A?  I'm curious about the altitude and LTAN.  Are all the payloads going to be deployed in roughly the same target orbit?  Or will upper stage maneuver between payload deployments?  I didn't see anything about the orbit in the FAQ or on the Spaceflight web site when I last checked other than a statement that it's a sun synchronous orbit.  Thanks.

[ZachS09]

Sorry if  this has already been answered somewhere, but what are the target orbit parameters for SSO-A?  I'm curious about the altitude and LTAN.  Are all the payloads going to be deployed in roughly the same target orbit?  Or will upper stage maneuver between payload deployments?  I didn't see anything about the orbit in the FAQ or on the Spaceflight web site when I last checked other than a statement that it's a sun synchronous orbit.  Thanks.

Altitude is 575 kilometers, inclination is 98 degrees.

[AstroBrewer]

Altitude is 575 kilometers, inclination is 98 degrees.

Thanks.  Any idea how that orbit is phased relative to the sun?  Is it a dawn/dusk orbit that's always in sun or some other sun synchronous orbit where it goes in and out of Earth's shadow every orbit?  What is the local time on the ground at the point directly under the satellites when they cross the equator (LTAN or LTDN)? 

[Comga]

Altitude is 575 kilometers, inclination is 98 degrees.

Thanks.  Any idea how that orbit is phased relative to the sun?  Is it a dawn/dusk orbit that's always in sun or some other sun synchronous orbit where it goes in and out of Earth's shadow every orbit?  What is the local time on the ground at the point directly under the satellites when they cross the equator (LTAN or LTDN)? 

It’s scheduled to launch at 10:32 AM local time, so it appears that the descending crossing of the Equator will be around 10AM.

[AstroBrewer]

It’s scheduled to launch at 10:32 AM local time, so it appears that the descending crossing of the Equator will be around 10AM.

Of course, launch time.  I was so busy looking for the answer on line that I forgot to think about what I was looking for.  Duh.  Thanks.

[Ictogan]

Altitude is 575 kilometers, inclination is 98 degrees.

Thanks.  Any idea how that orbit is phased relative to the sun?  Is it a dawn/dusk orbit that's always in sun or some other sun synchronous orbit where it goes in and out of Earth's shadow every orbit?  What is the local time on the ground at the point directly under the satellites when they cross the equator (LTAN or LTDN)?

LTDN is 10:30.

[gongora]

https://twitter.com/wsm1/status/1066474401191800832

Exciting week ahead: 2 rockets going up w/ 21 @PlanetLabs satellites scheduled within 24-hour period! First @SpaceX Falcon 9 from California then PSLV from India! Each includes tech demos of our badass next gen Doves -- more to be revealed on that later. W00t!

[Steven Pietrobon]

Exciting week ahead: 2 rockets going up w/ 21 @PlanetLabs satellites scheduled within 24-hour period! First @SpaceX Falcon 9 from California then PSLV from India! Each includes tech demos of our badass next gen Doves -- more to be revealed on that later. W00t!

I have three Flock-3 cubesats on SSO-A and 16 on PSLV. Anyone know where the other two are?

[strawwalker]

I have three Flock-3 cubesats on SSO-A and 16 on PSLV. Anyone know where the other two are?

Probably referring to the two SkySats going up on SSO-A.

[gongora]

Be The First To Catch A Signal From ESEO

16 November 2018
It is time to prepare to listen to space. To celebrate the launch of the European Student Earth Orbiter (ESEO), ESA’s Education Office challenges the amateur radio community to listen out to be first to hear the new spacecraft orbiting Earth.

ESEO is currently due to be launched between 22 and 25 November 2018 from the Vandenberg Air Force Base, as part of the SSO-A launch; spacecraft separation and activation is scheduled at about 2 hours 13 minutes after launch.

About two minutes after being deployed into its final orbit, ESEO will begin transmitting with its beacon signals to Earth that can be picked up by anyone with common amateur radio equipment. ESA challenges anyone to send to  [email protected]  the recording of the signal of the 437.00 MHz signal received from ESEO during its pass in visibility of their ground station.

...

[Jcc]

Pacific freedom and Just Read the Instructions have departed port once again for Wednesday's landing just offshore of the coast of Vandy:

https://mobile.twitter.com/SpaceXFleet/status/1066807523674660864

I wonder why JRTI is stationed just off the coast near the launch site, while  it needs to return to Long Beach with the stage. I guess the distances are relatively short anyway, and they need an area which can be blocked off with NOTAM, and not interfere with shipping.

[Joffan]

Pacific freedom and Just Read the Instructions have departed port once again for Wednesday's landing just offshore of the coast of Vandy:

I wonder why JRTI is stationed just off the coast near the launch site, while  it needs to return to Long Beach with the stage. I guess the distances are relatively short anyway, and they need an area which can be blocked off with NOTAM, and not interfere with shipping.

Yes, I think that minimizing inconvenience by retracing the launch track is probably the answer, to limit the affected area.

[mme]

Pacific freedom and Just Read the Instructions have departed port once again for Wednesday's landing just offshore of the coast of Vandy:

I wonder why JRTI is stationed just off the coast near the launch site, while  it needs to return to Long Beach with the stage. I guess the distances are relatively short anyway, and they need an area which can be blocked off with NOTAM, and not interfere with shipping.

Yes, I think that minimizing inconvenience by retracing the launch track is probably the answer, to limit the affected area.

Any chance they'll use the dock at VAFB? No need to transport back to Hawthorne if all that is needed is an inspection before the next reflight.

[Johnnyhinbos]

Pacific freedom and Just Read the Instructions have departed port once again for Wednesday's landing just offshore of the coast of Vandy:

I wonder why JRTI is stationed just off the coast near the launch site, while  it needs to return to Long Beach with the stage. I guess the distances are relatively short anyway, and they need an area which can be blocked off with NOTAM, and not interfere with shipping.

Yes, I think that minimizing inconvenience by retracing the launch track is probably the answer, to limit the affected area.

Any chance they'll use the dock at VAFB? No need to transport back to Hawthorne if all that is needed is an inspection before the next reflight.

Doubtful - they need the fixed mount stand at Port of LA to remove the legs.

[Wolfram66]

Slipping pending official announcement:

https://twitter.com/nextspaceflight/status/1067495192880693249

The offending weather is seen on the satellite feed
http://tropic.ssec.wisc.edu/real-time/eastpac/movies/g9irn/g9irn_loop.html

[Bubbinski]

Just checked the Lompoc weather at keyt.com, yes tomorrow and Thursday are forecast rainy. Forecast is partly cloudy for Friday and 40% chance of rain for Saturday. Of course this isn’t the last word, hoping the weather allows a weekend launch.

[Wolfram66]

This is some wicked wind shear... rockets do not like flying through this...

https://www.spc.noaa.gov/exper/soundings/18112812_OBS/

https://www.spc.noaa.gov/  go to Forecast Tools

[rosbif73]

If SSO-A ends up slipping further to Dec 4th, would SpaceX be capable of handling two launches on the same day?

Given that the SSO-A launch is scheduled for 18:32 UTC on Dec 2nd, presumably it would be within an hour or so of that time of day if it slips to the 4th, whereas CRS-SpX16 is 18:38 UTC on Dec 4th. Awfully close...