Author Topic: SpaceX F9 : Iridium NEXT 6 with GRACE-FO : NET Mar 21, 2018  (Read 15733 times)

Online FutureSpaceTourist

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Good find, thank you. Also a lot of other Iridium flights to fit in first, unless they change the order.

Online gongora

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Just stumbled across the Office of Safety & Mission Assurance's long-term planning schedule for Safety & Mission Success Reviews which shows tentative launch date for GRACE-FO of 2018-03-21.  That date was current based on an ELV milestone schedule from August 2nd.  I won't be too surprised if this date doesn't hold since it's still quite a ways out, especially since then they'd have a bunch of very high profile launches currently scheduled for that month: DM-1, TESS, GRACE-FO.  TESS has a harder deadline for launch and DM-1 is vital for their crew schedules.

Link to SMSR .pdf

The last date we heard for DM-1 is February, and SpaceX should be capable of doing back-to-back days on the launches of TESS and GRACE-FO.  I've just been wondering whether this needed to come after the other 7 Iridium launches.  Maybe that's not a requirement.
« Last Edit: 08/23/2017 02:28 AM by gongora »

Online gongora

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Tweet from Matt Desch:
Quote
Ten. Always 10, except Launch 6 will be a rideshare with GRACE, and that one will launch 5.

That fits perfectly with the NASA schedule we've seen.

Offline JoerTex

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For those with family who 'need to know' about GRACE, here is a newspaper link covering the mission, and ends with GRACE-FO.

https://www.nytimes.com/2017/09/12/magazine/what-could-we-lose-if-a-nasa-mission-goes-dark.html
« Last Edit: 09/16/2017 03:40 AM by gongora »

Online gongora

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The original GRACE satellites are set to be retired before GRACE-FO launches.

[JPL] GRACE Mission Making Plans for Final Science Data Collection
Quote
The team expects the October/November science data collection to be the mission's last before GRACE-2 runs out of fuel. The additional monthly gravity map produced will help further extend GRACE's data record closer to the launch of GRACE's successor mission, GRACE-Follow-On, scheduled for early 2018.

As directed by the mission's Joint Steering Group, final decommissioning for both GRACE-1 and GRACE-2 will begin once the dual satellite science phase concludes.

Offline OccasionalTraveller

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JPL's Grace-FO website is now showing a launch countdown of 79 days 14 hours (as of writing). I think that would make it 8 December 2017 at 0800 UTC.

This seems unlikely if it remains Iridium-NEXT Flight 6, unless the launches go out of order. Is the current predicted date based on anything other than an average interval between launches? Can SpaceX accelerate launches 4, 5 and 6 to achieve this date?
« Last Edit: 09/22/2017 03:16 AM by gongora »

Online gongora

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JPL's Grace-FO website is now showing a launch countdown of 79 days 14 hours (as of writing). I think that would make it 8 December 2017 at 0800 UTC.

This seems unlikely if it remains Iridium-NEXT Flight 6, unless the launches go out of order. Is the current predicted date based on anything other than an average interval between launches? Can SpaceX accelerate launches 4, 5 and 6 to achieve this date?

The March date was from a NASA schedule.  It's unlikely they get in a fifth launch this year.  There's no way they get in a sixth launch this year.

Offline Steven Pietrobon

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JPL's Grace-FO website is now showing a launch countdown of 79 days 14 hours (as of writing). I think that would make it 8 December 2017 at 0800 UTC.

That website is saying early 2018 for the launch, so that count down clock is wrong.

https://gracefo.jpl.nasa.gov/mission/overview/
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline deruch

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JPL's Grace-FO website is now showing a launch countdown of 79 days 14 hours (as of writing). I think that would make it 8 December 2017 at 0800 UTC.

That website is saying early 2018 for the launch, so that count down clock is wrong.

https://gracefo.jpl.nasa.gov/mission/overview/
It's possible that given the news that the original GRACE sats are going to be decommissioned very soon that the Iridium launch order has been swapped to allow for the possibility of overlapping coverage with GRACE-FO as originally intended.  That would mean that the GRACE-FO+(5) IrNext sats would go up on Launch#4 instead of Launch#6.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Online gongora

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JPL's Grace-FO website is now showing a launch countdown of 79 days 14 hours (as of writing). I think that would make it 8 December 2017 at 0800 UTC.

That website is saying early 2018 for the launch, so that count down clock is wrong.

https://gracefo.jpl.nasa.gov/mission/overview/
It's possible that given the news that the original GRACE sats are going to be decommissioned very soon that the Iridium launch order has been swapped to allow for the possibility of overlapping coverage with GRACE-FO as originally intended.  That would mean that the GRACE-FO+(5) IrNext sats would go up on Launch#4 instead of Launch#6.

Four days ago the CEO of Iridium said it was still planned to be flight 6

Offline deruch

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JPL's Grace-FO website is now showing a launch countdown of 79 days 14 hours (as of writing). I think that would make it 8 December 2017 at 0800 UTC.

That website is saying early 2018 for the launch, so that count down clock is wrong.

https://gracefo.jpl.nasa.gov/mission/overview/
It's possible that given the news that the original GRACE sats are going to be decommissioned very soon that the Iridium launch order has been swapped to allow for the possibility of overlapping coverage with GRACE-FO as originally intended.  That would mean that the GRACE-FO+(5) IrNext sats would go up on Launch#4 instead of Launch#6.

Four days ago the CEO of Iridium said it was still planned to be flight 6
I'm aware.  I think it's entirely within the realm of possibility that an agreement to swap launch order could have been quickly hammered out, assuming the GRACE-FO s/c can be prepared in time for the earlier launch.  In fact, such an agreement could have been discussed much earlier as an option for fast action.  So, while I think the current March schedule should still be the target date for the thread I won't be at all surprised to learn that the swap has been approved.  Having even a very little bit of overlapping measurement is hugely important to the usefulness of the GRACE-FO data.  Compensating Iridium for any projected revenue losses due to delayed coverage shouldn't be that difficult.  I'm not sure how "individualized" each of the Iridium NEXT s/c are or whether they are all perfectly interchangeable.  Does anyone know?
« Last Edit: 09/22/2017 05:08 AM by deruch »
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Online gongora

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(translation by Google)
Grace FO satellites look through the surface
Quote
Two satellites built at Airbus in Immenstaad, which are to continue surveying the earth's gravitational field over the next five years, were last presented on German soil at IABG in Ottobrunn near Munich on Friday
...
The twins were developed on behalf of the Jet Propulsion Laboratory (JPL) of the American Space Agency NASA and the German Geo-Research Center (GFZ) in Potsdam.
...
Each of the two satellites weighs 655 kilograms. To start, they are clamped on a carbon fiber fixture and released in orbit. For attitude control and control, each has 32 kilograms of fuel (nitrogen gas) on board
...
On December 12, the Grace-FO will be flown with a jumbo jet and 40 tons of equipment from Munich to California. At the Air Force Base in Vandenberg, the satellites are mounted on the fixture and tested again for their function. Then they come in a capsule on the Raktspitze, are refueled and started in mid-March 2018 with a Falcon rocket.

Online speedevil

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It's possible that given the news that the original GRACE sats are going to be decommissioned very soon that the Iridium launch order has been swapped to allow for the possibility of overlapping coverage with GRACE-FO as originally intended.  That would mean that the GRACE-FO+(5) IrNext sats would go up on Launch#4 instead of Launch#6.

Certainly not alas.
http://www2.csr.utexas.edu/grace/

Quote
After more than 15 productive years in orbit, the U.S./German GRACE (Gravity Recovery and Climate Experiment) satellite mission has ended science operations. During their mission, the twin GRACE satellites have provided unprecedented insights into how our planet is changing by tracking the continuous movement of liquid water, ice and the solid Earth.

GRACE made science measurements by precisely measuring the distance between its twin satellites, GRACE-1 and GRACE-2, which required that both spacecraft and their instruments be fully functional. Following an age-related battery issue on GRACE-2 in September, it became apparent by mid-October that GRACE-2's remaining battery capacity would not be sufficient to operate its science instruments and telemetry transmitter. Consequently, the decision was made to decommission the GRACE-2 satellite and end GRACE's science mission.

Despite the loss of one of the twin GRACE satellites, the other satellite, GRACE-1, will continue operating through the end of 2017. "GRACE-1's remaining fuel will be used to complete previously planned maneuvers to calibrate and characterize its accelerometer to improve the final scientific return and insights from the 15-year GRACE record," said GRACE Project Scientist Carmen Boening of JPL.

Currently, GRACE-2's remaining fuel is being expended and the satellite has begun to slowly deorbit. Atmospheric reentry of GRACE-2 is expected sometime in December or January. Decommissioning and atmospheric reentry of GRACE-1 are expected in early 2018. NASA and the German Space Operations Center will jointly monitor the deorbit and reentry of both satellites.

Even if 'early 2018' overlaps with launch dates, the loss of one satellite means there is no meaningful gravitational measurement going on at all.

A fifteen year mission is just an awesome achievement.

I have not investigated closely and it appears that the GRACE-FO satellites are using a very similar design, and while in principle you could operate GRACE-FO with GRACE-1, the orbit GRACE-FO will be put in will be very much higher, so this is not possible, even if the satellites are actually compatible.

(GRACE1/2's orbit has decayed significantly)

Offline russianhalo117

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It's possible that given the news that the original GRACE sats are going to be decommissioned very soon that the Iridium launch order has been swapped to allow for the possibility of overlapping coverage with GRACE-FO as originally intended.  That would mean that the GRACE-FO+(5) IrNext sats would go up on Launch#4 instead of Launch#6.

Certainly not alas.
http://www2.csr.utexas.edu/grace/

Quote
After more than 15 productive years in orbit, the U.S./German GRACE (Gravity Recovery and Climate Experiment) satellite mission has ended science operations. During their mission, the twin GRACE satellites have provided unprecedented insights into how our planet is changing by tracking the continuous movement of liquid water, ice and the solid Earth.

GRACE made science measurements by precisely measuring the distance between its twin satellites, GRACE-1 and GRACE-2, which required that both spacecraft and their instruments be fully functional. Following an age-related battery issue on GRACE-2 in September, it became apparent by mid-October that GRACE-2's remaining battery capacity would not be sufficient to operate its science instruments and telemetry transmitter. Consequently, the decision was made to decommission the GRACE-2 satellite and end GRACE's science mission.

Despite the loss of one of the twin GRACE satellites, the other satellite, GRACE-1, will continue operating through the end of 2017. "GRACE-1's remaining fuel will be used to complete previously planned maneuvers to calibrate and characterize its accelerometer to improve the final scientific return and insights from the 15-year GRACE record," said GRACE Project Scientist Carmen Boening of JPL.

Currently, GRACE-2's remaining fuel is being expended and the satellite has begun to slowly deorbit. Atmospheric reentry of GRACE-2 is expected sometime in December or January. Decommissioning and atmospheric reentry of GRACE-1 are expected in early 2018. NASA and the German Space Operations Center will jointly monitor the deorbit and reentry of both satellites.

Even if 'early 2018' overlaps with launch dates, the loss of one satellite means there is no meaningful gravitational measurement going on at all.

A fifteen year mission is just an awesome achievement.

I have not investigated closely and it appears that the GRACE-FO satellites are using a very similar design, and while in principle you could operate GRACE-FO with GRACE-1, the orbit GRACE-FO will be put in will be very much higher, so this is not possible, even if the satellites are actually compatible.

(GRACE1/2's orbit has decayed significantly)
GRACE 1 and 2 are at end of life station keeping wise and are super low on propellant. If there was an immediate means to refuel them then they could 2 or more decades. As for GRACE-FO, they are the GRACE-1 and 2 flight spares and have been in storage since they were built. The were pulled out of storage to receive minor upgrades of components and the addition of laser optics for ranging between the two spacecraft.

Online speedevil

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GRACE 1 and 2 are at end of life station keeping wise and are super low on propellant. If there was an immediate means to refuel them then they could 2 or more decades. As for GRACE-FO, they are the GRACE-1 and 2 flight spares and have been in storage since they were built. The were pulled out of storage to receive minor upgrades of components and the addition of laser optics for ranging between the two spacecraft.
I hadn't realised they were flight spares, thanks.
Grace 2 has had a pretty terminal battery issue, and seems unlikely to last decades.
(of course, if it was swapped...)

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