SpaceX F9 : Starlink v1.0 L8 Rideshare : June 13, 2020

[gongora]

Thread for Starlink v1.0 Flight 8.  This is the first Starlink rideshare mission.

Check the Starlink Index Thread for links to more Starlink information.

NSF Threads for Starlink v1.0 Flight 8: Discussion

NSF News Articles for Starlink:
https://www.nasaspaceflight.com/?s=Starlink

Successful launch June 13, 2020 at 5:21am EDT (09:21 UTC) on Falcon 9 (booster 1059.3).  Fairing halves are reused.  ASDS landing was successful.  The payloads were deployed in a 213 x 367 km x 53.0 deg orbit.

Payload: 58 Starlink satellites plus rideshare satellites.  Planet will have three SkySat satellites (16-18) on this flight.  The SkySat satellites are each 110kg.  They will be mounted on top of the Starlink satellites.

Please use the Starlink Discussion Thread for all general discussion on Starlink.

L2 SpaceX:
https://forum.nasaspaceflight.com/index.php?board=60.0

From a previous mission's Press Kit:

Each Starlink satellite weights approximately 260 kg and features a compact, flat-panel design that minimizes volume, allowing for a dense launch stack to take full advantage of Falcon 9’s launch capabilities. With four powerful phased array and two parabolic antennas on each satellite ... At end of their life cycle, the satellites will utilize their on-board propulsion system to deorbit over the course of a few months. In the unlikely event their propulsion system becomes inoperable, the satellites will burn up in Earth’s atmosphere within 1-5 years, significantly less than the hundreds or thousands of years required at higher altitudes. Further, Starlink components are designed for full demisability.

Starlink is targeting service in the Northern U.S. and Canada in 2020, rapidly expanding to near global coverage of the populated world by 2021. Additional information on the system can be found at starlink.com.

For this mission:

SpaceX is targeting Saturday, June 13 at 5:21 a.m. EDT, 9:21 UTC, for launch of its ninth Starlink mission, which will include 58 Starlink satellites and three of Planet’s SkySats. Falcon 9 will lift off from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, and a backup opportunity is available on Sunday, June 14 at 4:59 a.m. EDT, 8:59 UTC. This mission marks SpaceX’s first SmallSat Rideshare Program launch.

Falcon 9’s first stage previously supported Dragon’s 19th and 20th resupply missions to the International Space Station. Following stage separation, SpaceX will land Falcon 9’s first stage on the “Of Course I Still Love You” droneship, which will be stationed in the Atlantic Ocean. Half of Falcon 9’s fairing previously flew on the JCSAT-18/Kacific1 mission, and the other half previously flew on SpaceX’s third Starlink mission.

Planet’s SkySats will deploy sequentially beginning about 12 minutes after liftoff, and the Starlink satellites will deploy approximately 26 minutes after liftoff.

[gongora]

[Planet] SkySats 16-21 To Launch On SpaceX Falcon 9 Rideshare Missions
Mike Safyan | May 13, 2020

Planet is set to launch six more SkySat satellites (SkySats 16-21) into Low Earth Orbit this summer, rounding out the fleet of 15 SkySats already in operation.

SkySats 1-15 operate in Sun Synchronous Orbits, a specific type of Low Earth Orbit that results in the Earth’s surface always being illuminated by the Sun at the same angle when the satellite is capturing imagery. About half of the SkySats currently pass overhead in a morning crossing plane, while the other half moves in an afternoon crossing plane, so together they provide twice-daily coverage of select areas on a global scale. SkySats 16-21 will operate at a “mid-inclination” orbit of 53 degrees, complimenting the Sun Synchronous fleet, and will offer more targeted coverage and thus unrivaled rapid-revisits and raw image capacity in key geographic regions.

The six SkySats will be evenly split across two launches on SpaceX’s Falcon 9, a two-stage reusable rocket that has successfully flown satellites and cargo over 80 times to orbit. They will do so as rideshare payloads on launches of SpaceX’s Starlink satellites.

SkySats 16-18 will launch on SpaceX’s ninth Starlink mission, targeted for launch in the next month, and SkySats 19-21 will launch later this summer. Both missions will launch from Cape Canaveral Air Force Base in Florida.

The launch of SkySats 16-21, as well as the development of our enhanced 50 cm imagery (to be made available to customers this year)—are just some examples of Planet’s continuously evolving industry-leading geospatial offerings. Stay tuned to the Pulse blog for more launch and product updates in the coming months.

[Skyrocket]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

[gongora]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

I'm assuming it reduced the number of Starlink satellites, but we haven't seen what the payload stack looks like.  I don't see how you'd put rideshares on top of the Starlink stack, and if you put them on the bottom I don't see how you keep the same number of Starlinks.

[Star One]

As this is Planet’s next launch I will put this very recent article from their website here:

https://www.planet.com/pulse/journalists-use-satellite-data-to-track-pollution-kim-jong-un-and-more-during-covid-19-pandemic/

[freda]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

I'm assuming it reduced the number of Starlink satellites, but we haven't seen what the payload stack looks like.  I don't see how you'd put rideshares on top of the Starlink stack, and if you put them on the bottom I don't see how you keep the same number of Starlinks.

And.. the orbits typical for Starlink and Planet do not seem compatible with a single deployment.  Will Planet (SSO orbit) get a post-Starlink-deployment boost?

[gongora]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

I'm assuming it reduced the number of Starlink satellites, but we haven't seen what the payload stack looks like.  I don't see how you'd put rideshares on top of the Starlink stack, and if you put them on the bottom I don't see how you keep the same number of Starlinks.

And.. the orbits typical for Starlink and Planet do not seem compatible with a single deployment.  Will Planet (SSO orbit) get a post-Starlink-deployment boost?

The Planet sats are going to the same 53 degree inclination, and I think will be dropped off in the same orbit.  These Planet sats have propulsion, they're not Doves.

[Robotbeat]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

I'm assuming it reduced the number of Starlink satellites, but we haven't seen what the payload stack looks like.  I don't see how you'd put rideshares on top of the Starlink stack, and if you put them on the bottom I don't see how you keep the same number of Starlinks.

Why not? They’re small and only 100kg each (total 300kg plus dispenser) out of a payload of like 16 tons.

[gongora]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

I'm assuming it reduced the number of Starlink satellites, but we haven't seen what the payload stack looks like.  I don't see how you'd put rideshares on top of the Starlink stack, and if you put them on the bottom I don't see how you keep the same number of Starlinks.

Why not? They’re small and only 100kg each (total 300kg plus dispenser) out of a payload of like 16 tons.

If they're on an ESPA ring then you're raising the Starlink sats by the height of an ESPA ring.  Would all of that fit in the fairing?

[groknull]

Do the three rideshare satelllies reduce the number of Starlink satellites or will there still be the full complement of 60 Starlinks?

I'm assuming it reduced the number of Starlink satellites, but we haven't seen what the payload stack looks like.  I don't see how you'd put rideshares on top of the Starlink stack, and if you put them on the bottom I don't see how you keep the same number of Starlinks.

Why not? They’re small and only 100kg each (total 300kg plus dispenser) out of a payload of like 16 tons.

If they're on an ESPA ring then you're raising the Starlink sats by the height of an ESPA ring.  Would all of that fit in the fairing?

WAG: A stack of 60 Starlink satellites raised by an ESPA ring would not fit in the fairing.

Starlink 0.9 stack appeared to be a custom Starlink specific Payload Attach Fitting (PAF) with a large platform for the Starlink stack.  There does not appear to be an ESPA compatible ring on that PAF.
https://forum.nasaspaceflight.com/index.php?topic=48135.msg1945139#msg1945139

Musk's tweet (in same post) indicated it was a tight fit with the stack of 60.

I have not seen later stack images with a different PAF*.  Since the platform does not appear to connect to a center standard ring, and braces appear to run from the platform to the circular stiffener on the PAF, it seems unlikely that an ESPA ring would fit under the stack.

In addition, Moog indicates that the standard ESPA ring can handle a 17,000 lb primary payload.  The first 60 satellite stack was over 30,000 lbs.
https://www.moog.com/content/dam/moog/literature/Space_Defense/spaceliterature/structures/moog-espa-users-guide-datasheet.pdf
A custom ESPA ring with a higher payload capability is certainly possible.

IMO, creating an active dispenser satellite based on a modified Starlink satellite bus would be more like SpaceX:
- development of in-house capability - vertical integration in a business sense
- no modification of Starlink PAF - no need to choose which PAF to fly for a particular Starlink mission
- fits on one top of stack position (other side of stack is face down)
- relaxed height limitations
- bulk of mission flow could be identical with or without rideshare partners
- allows rideshare deployment before or after Starlink stack delpoyment
- post Starlink deployment (dispenser deploys with Starlink stack, deploys rideshare satellites later) allows inclination and orbit changes before rideshare satellite deployment
- leverages standard Starlink satellite components
- develops experience for tug/retrieval capabilities
- dispenser satellite could deorbit after rideshare deployment, or remain in orbit for other purposes

Some issues (not exhaustive):
- power / communication / environmental and other support requirements of the rideshare satellite may not match in-stack resources
- deployment dynamics with rideshare satellites attached
- compatibility with existing deployment tension rod architecture

* links to such images encouraged

[gongora]

SpaceX can make their own rings with ESPA ports to whatever specification they need.  I very much disagree that making some sort of dispenser sat would be more like SpaceX, quite the opposite in my opinion.

[Robotbeat]

Without actual measurements, I doubt we can assume you *can’t* still fit 60 Starlink satellites in there. Possible, but far from safe to assume there won’t be 60 in there. They may have improved packing slightly, there may be more room than there appears, and (unlikely but certainly possible) they may be trying a longer fairing.

[Comga]

Without actual measurements, I doubt we can assume you *can’t* still fit 60 Starlink satellites in there. Possible, but far from safe to assume there won’t be 60 in there. They may have improved packing slightly, there may be more room than there appears, and (unlikely but certainly possible) they may be trying a longer fairing.

Or SpaceX mounted them on the top of the topmost two Starlink satellites.
There is plenty of volume up in the tip of the fairing.
The satellites, being nearly identical to the ones on the bottom of the stack can surely take the load.
By the bottom of the stack the increase in load is insignificant.
Minimal changes and development, still all in-house

[groknull]

Without actual measurements, I doubt we can assume you *can’t* still fit 60 Starlink satellites in there. Possible, but far from safe to assume there won’t be 60 in there. They may have improved packing slightly, there may be more room than there appears, and (unlikely but certainly possible) they may be trying a longer fairing.

Or SpaceX mounted them on the top of the topmost two Starlink satellites.
There is plenty of volume up in the tip of the fairing.
The satellites, being nearly identical to the ones on the bottom of the stack can surely take the load.
By the bottom of the stack the increase in load is insignificant.
Minimal changes and development, still all in-house

This makes sense.

We haven't seen many (any?) pictures of what the top of the anchored stack looks like.  Or details on the top ends of the tension rods.  Or video of the tension rod (and associated hardware) release.

Top of stack rideshare mount structures may already have been on previous launches.

I can envision the tension rods each having a sort of spring loaded elbow and forearm at the top, with the forearms meeting a structure in the middle.  On release, the springs cause the tension rods to straighten out, with the resulting momentum peeling them quickly off the sides of the stack.

A central rideshare mount structure could be a flat (honeycomb) plate with a 1575mm bolted ring on it.  Or one or more of the forearms could each have bolted ring or clamp band attachment points.

[whitelancer64]

Without actual measurements, I doubt we can assume you *can’t* still fit 60 Starlink satellites in there. Possible, but far from safe to assume there won’t be 60 in there. They may have improved packing slightly, there may be more room than there appears, and (unlikely but certainly possible) they may be trying a longer fairing.

Or, more simply, they make the 4 aluminum tension rods that hold the Starlinks together shorter... no need to overthink it.

Also, keeping the dispenser for the rideshare sats on the 2nd stage reduces orbital debris.

[Comga]

Without actual measurements, I doubt we can assume you *can’t* still fit 60 Starlink satellites in there. Possible, but far from safe to assume there won’t be 60 in there. They may have improved packing slightly, there may be more room than there appears, and (unlikely but certainly possible) they may be trying a longer fairing.

Or, more simply, they make the 4 aluminum tension rods that hold the Starlinks together shorter... no need to overthink it.

Also, keeping the dispenser for the rideshare sats on the 2nd stage reduces orbital debris.

Unless the mechanism is just a releasing clamp on each of the top two Starlink satellites that stays attached to those Starlinks.
Releasing the carrier is another mechanism, in addition to leaving debris. 
(That would one good thing about an ESPA ring fixed to the top of the second stage.)

Occam's razor.
Starlink satellites fill the cylindrical part of the fairing.
The ogive nose part is empty.
Starlink satellites can take launch loads from above.
There are two Starlink satellites in each layer.
The two rideshare payloads are much smaller and lighter than Starlink satelites
SpaceX wants to get the full Starlink constellation up as quickly as possible.
What accommodation would require the least modification and complication and impose the least burden on SpaceX and Starlink?

Either they mount the rideshares to the top two satellites or they make a full width structure for the top of the stack that can be configured to carry various numbers and types of rideshare payloads.  The former is simpler.

[groknull]

...
Releasing the carrier is another mechanism, in addition to leaving debris. 
(That would one good thing about an ESPA ring fixed to the top of the second stage.)
...

If the carrier is attached to one of the existing tension rods, or a carrier is on each tension rod, then the number of debris objects remains the same.  Debris mass does go up, and reentry does not occur as soon as second stage reentry.

If the carrier(s) are part of one or more of the tension rods, then the tension rod release mechanism is the carrier release mechanism.  No additional separation events.

[whitelancer64]

...
Releasing the carrier is another mechanism, in addition to leaving debris. 
(That would one good thing about an ESPA ring fixed to the top of the second stage.)
...

If the carrier is attached to one of the existing tension rods, or a carrier is on each tension rod, then the number of debris objects remains the same.  Debris mass does go up, and reentry does not occur as soon as second stage reentry.

If the carrier(s) are part of one or more of the tension rods, then the tension rod release mechanism is the carrier release mechanism.  No additional separation events.

This also means the rideshares HAVE to deploy before, or at or near to the same time as the Starlink satellites.

A dispenser on the bottom, still attached to the 2nd stage, means the Starlinks can be yeeted away and then the rideshares can deploy later. The 2nd stage can even move to a slightly different orbit before deployment.

[Comga]

...
Releasing the carrier is another mechanism, in addition to leaving debris. 
(That would one good thing about an ESPA ring fixed to the top of the second stage.)
...

If the carrier is attached to one of the existing tension rods, or a carrier is on each tension rod, then the number of debris objects remains the same.  Debris mass does go up, and reentry does not occur as soon as second stage reentry.

If the carrier(s) are part of one or more of the tension rods, then the tension rod release mechanism is the carrier release mechanism.  No additional separation events.

This also means the rideshares HAVE to deploy before, or at or near to the same time as the Starlink satellites.

A dispenser on the bottom, still attached to the 2nd stage, means the Starlinks can be yeeted away and then the rideshares can deploy later. The 2nd stage can even move to a slightly different orbit before deployment.

That puts priority on the two 100 kg rideshare satellites over the stack of 60- 500 kg Starlink satellites.
Occam's razor fail

I had to look up "yeeted".      
Urban dictionary says that for throwing away things of no value. 
Ain't gonna yeet no 60 Starlinks.

[gongora]

[Spaceflight Now] Planet reserves rideshare slots on SpaceX Starlink launches

Mike Safyan, vice president of launch for San Francisco-based Planet, said the SkySat satellites will be mounted at the very top of the stack of Starlink payloads inside the fairing on each Falcon 9 flight. The SkySats will attach to the Starlink stack using a custom adapter.