SpaceX Falcon 9 : NASA IXPE : KSC LC-39A : 9 December 2021 (0600 UTC)

[gongora]

NASA SMSR schedule shows this as May 31, 2021.

NASA LAUNCH SERVICES I MOD 127: This is a bilateral modification to revise the Imaging X-Ray Polarimetry Explorer (IXPE) launch date from a launch date of April 2021 to May 31, 2021 due to a Government caused delay and to include terms for acceptance of previously flown hardware.  The work plan, payment schedule, and mission solution are revised.

[gongora]

[Spaceflight Now] Coronavirus work stoppage likely to delay launch of NASA X-ray astronomy mission

A nearly three-month stoppage of on-site work due to concerns about the spread of the coronavirus at NASA’s Marshall Space Fight Center in Alabama is expected to push back the launch of the IXPE X-ray astronomy satellite from May 2021 until some time later next year, a senior space agency official said.

[mn]

https://spacenews.com/pandemic-delays-launch-of-nasa-astrophysics-smallsat-mission/

In a talk at the 34th Annual Conference on Small Satellites, Bill Deininger, chief system engineer on IXPE at Ball Aerospace, which is providing the spacecraft, said the mission was now planning a September 2021 launch for IXPE

[TrevorMonty]

Looks like F9 was cheaper in more ways than  actual launch costs.

https://spacenews.com/pandemic-delays-launch-of-nasa-astrophysics-smallsat-mission/

When we originally put this concept together, Pegasus was the only vehicle available for a zero-degree-inclination orbit over 500 kilometers,” he said. The change in vehicles requires some work to adjust to the different structural, acoustical and thermal environments of the Falcon 9, he noted.
However, Deininger said the use of the Falcon 9 has benefits beyond the lower cost. The Falcon will place IXPE into a slightly higher orbit, at about 600 kilometers, which will allow for a longer scientific lifetime for the mission. The far larger volume available inside the Falcon 9 payload fairing also allowed the mission to redesign X-ray shields on one end of the spacecraft, eliminating deployment mechanisms that simplify the spacecraft.

[Comga]

If the Falcon 9 had been available when the mission was planned, it would have been possible to greatly simplify the spacecraft and further lower costs.
Major subsystems on the IXPE spacecraft are the extendable boom and the Tip-Tilt-Rotate mechanism on its end to tweak the final position. This could be replaced with a rigid tube given the length of the Falcon 9 fairing. This would also be higher performing because at least one of the intended targets is anticipated to be blurred and degraded by the flexing of the deployable boom.

The IXPE solar panels are deployable and have launch latches, which wouldn’t be needed on a spacecraft designed for the F9. Some panels have corners cut to avoid the limits of the Pegasus dynamic envelope, which is a minor complication that could also be avoided.

As mentioned above, the deployable X-ray shields that prevent sneak paths to the detectors have been replaced with a single rigid and fixed shield, so one additional savings was achieved with the dramatically larger volume of F9, even with the late change.

Plus the mission could ride-share and spread some of the cost  of the rocket over additional payloads. 

Despite the continued maintenance of Stargazer, I don’t expect Pegasus to make any new sales given the clear superiority of the Falcon 9.

[gongora]

NASA LAUNCH SERVICES II - SPACE EXPLORATION TECHNOLOGIES. MOD 137: REVISES THE IMAGING X-RAY POLARIMETRY EXPLORER (IXPE) LAUNCH DATE FROM MAY 31, 2021 TO SEPTEMBER 15, 2021 AND TO PROVIDE INCREMENTAL FUNDING.

[Comga]

NASA LAUNCH SERVICES II - SPACE EXPLORATION TECHNOLOGIES. MOD 137: REVISES THE IMAGING X-RAY POLARIMETRY EXPLORER (IXPE) LAUNCH DATE FROM MAY 31, 2021 TO SEPTEMBER 15, 2021 AND TO PROVIDE INCREMENTAL FUNDING.

This delay was not unexpected
The program has been sitting on this announcement for some time.
That launch date is less than a year from today. 
The odds of it holding are not good. IMO

[Lars-J]

NASA LAUNCH SERVICES II - SPACE EXPLORATION TECHNOLOGIES. MOD 137: REVISES THE IMAGING X-RAY POLARIMETRY EXPLORER (IXPE) LAUNCH DATE FROM MAY 31, 2021 TO SEPTEMBER 15, 2021 AND TO PROVIDE INCREMENTAL FUNDING.

This delay was not unexpected
The program has been sitting on this announcement for some time.
That launch date is less than a year from today. 
The odds of it holding are not good. IMO

What is the major factor of the delay? The spacecraft not being ready? SpaceX issues? Covid?

[smoliarm]

NASA LAUNCH SERVICES II - SPACE EXPLORATION TECHNOLOGIES. MOD 137: REVISES THE IMAGING X-RAY POLARIMETRY EXPLORER (IXPE) LAUNCH DATE FROM MAY 31, 2021 TO SEPTEMBER 15, 2021 AND TO PROVIDE INCREMENTAL FUNDING.

This delay was not unexpected
The program has been sitting on this announcement for some time.
That launch date is less than a year from today. 
The odds of it holding are not good. IMO

What is the major factor of the delay? The spacecraft not being ready? SpaceX issues? Covid?

spaceflightnow, July 2, 2020, by Stephen Clark:
"Coronavirus work stoppage likely to delay launch of NASA X-ray astronomy mission"

[Comga]

NASA LAUNCH SERVICES II - SPACE EXPLORATION TECHNOLOGIES. MOD 137: REVISES THE IMAGING X-RAY POLARIMETRY EXPLORER (IXPE) LAUNCH DATE FROM MAY 31, 2021 TO SEPTEMBER 15, 2021 AND TO PROVIDE INCREMENTAL FUNDING.

This delay was not unexpected
The program has been sitting on this announcement for some time.
That launch date is less than a year from today. 
The odds of it holding are not good. IMO

What is the major factor of the delay? The spacecraft not being ready? SpaceX issues? Covid?

As stated in the linked article it’s mostly the CoVid shutdown of MSFC impacting the assembly and delivery of the Multiple Mirror Modules. There was also some delay to the Italian detector modules due to travel restrictions, and probably work delays there, too.
The spacecraft build is fine. I am told that their jobs were a little easier during the MSFC shutdown because the daily status meetings were suspended.  
The article is a bit suspect. It has the old 540 km orbit altitude. It is posted above that the orbit has been raised to 600 km to increase the orbital lifetime. Lacking that makes me suspect how well sourced the article is.
There are other issues whose resolution may further impact the launch date. 

[zubenelgenubi]

Confirmation from Pandemic may delay several NASA astrophysics missions, dated September 24

September 21 meeting of the Astronomy and Astrophysics Advisory Committee, Paul Hertz, director of NASA’s astrophysics division:

At the small end of the scale is the Imaging X-ray Polarimetry Explorer (IXPE) spacecraft, an Explorer-class mission that was to launch next May. That launch has now slipped to at least September because of delays in assembly of the spacecraft caused by the closure of the Marshall Space Flight Center for three months due to the pandemic. Hertz said a formal revised launch date for IXPE should come after a review scheduled for October.

[Comga]

From the article:

In a talk at the 34th Annual Conference on Small Satellites, Bill Deininger, chief system engineer on IXPE at Ball Aerospace, which is providing the spacecraft, said the mission was now planning a September 2021 launch for IXPE.

“Because of the times that we live in, COVID-19 has had an impact on the project,” he acknowledged. Ball has taken on a bigger role in spacecraft assembly efforts to partially compensate for the delays, such as assuming responsibility for receiving and checking out the instruments. “We’ve been able to make solid progress on the spacecraft,” including powering on the spacecraft and loading flight software.

That article does discuss the increased orbital height of 600 km.

[Jansen]

https://ixpe.msfc.nasa.gov/news.html

IXPE Passed the Key Decision Point (KDP-D) Review
November 2, 2020: The IXPE mission has successfully passed the KDP-D review. NASA manages programs and projects by categorizing the steps necessary to complete the project. These steps or phaases are called Key Decision Points (KDP). IXPE is now in the Project Phase D, which is composed of: system assembly, integration and test, launch. IXPE's scheduled launch date is October 21, 2021.

[vaporcobra]

NET November 2021 as of 11/05/2020.

https://sma.nasa.gov/docs/default-source/sma-disciplines-and-programs/smsr/smsr-intergrated-master-schedule_24feb2020aab4a269d2a865b9a1a0ff0f003ca228.pdf?sfvrsn=8290faf8_14

[Jansen]

The Imaging X-ray Polarimetry Explorer will be launched on or after November 20, [2021] 2020 into a 540-km circular orbit at 0° inclination. During IXPE's two-year mission, targets such as active galactic nuclei (AGN), microquasars, pulsars and pulsar wind nebulae, magnetars, accreting X-ray binaries, supernova remnants, and the Galactic center will be studied.

Source: LSP Waterfall dated 11/5/2020

[Bean Kenobi]

The Imaging X-ray Polarimetry Explorer will be launched on or after November 20, 2020 into a 540-km circular orbit at 0° inclination. During IXPE's two-year mission, targets such as active galactic nuclei (AGN), microquasars, pulsars and pulsar wind nebulae, magnetars, accreting X-ray binaries, supernova remnants, and the Galactic center will be studied.

Source: LSP Waterfall dated 11/5/2020

2021 would be better.

[whitelancer64]

MOD 106: The purpose of this contract modification is to award and definitize the firm fixed price (FFP) launch service for the Imaging X-Ray Polarimetry Explorer (IXPE) mission pursuant to Contract Clause 14.0, entitled Launch Service Task Ordering (LSTO) Procedures. This FFP includes the Falcon 9 Standard Launch Service and Standard Mission Integration and five (5) Mission Unique Services (MUSs). The total firm fixed price for this Launch Service Task Order for all definitized work under Contract Line Item Number 6 (CLIN 6) is $42,049,411.

Is the full text of the contract available anywhere?

[gongora]

Is the full text of the contract available anywhere?

No

[vaporcobra]

NET November 17th, 2021.

[Jansen]

https://www.nasa.gov/centers/marshall/news/releases/2021/nasas-imaging-x-ray-polarimetry-explorer-prepares-for-environmental-testing.html

NASA's Imaging X-ray Polarimetry Explorer Prepares for Environmental Testing

Despite COVID-19-related hurdles, NASA's newest X-ray astronomy mission is a step closer to launch. Engineers recently completed integration of the agency's Imaging X-Ray Polarimetry Explorer, or IXPE, at Ball Aerospace in Boulder, Colorado. Now, Ball will put the fully assembled observatory through a series of tests that simulate the harsh conditions the small spacecraft will encounter on its rocket trip into space in late 2021.

"Reaching this milestone is a testament to the experience, commitment, and expertise of the IXPE team and our partners around the world," said IXPE principal investigator Martin Weisskopf of NASA's Marshall Space Flight Center in Huntsville, Alabama, who first conceived of the mission 30 years ago. "We're all looking forward to providing world-class science and expanding our view of the X-ray universe."

IXPE is the first small satellite mission dedicated to measuring the polarization of X-rays from a variety of cosmic sources — from black holes to exploded stars and jets traveling near the speed of light. IXPE's polarization measurements will complement observations from other telescopes in space now, including NASA's Chandra X-ray Observatory, adding new details about the nature of these mysterious objects and the environments close to them.

Upon completion, the IXPE observatory will be shipped to NASA's Kennedy Space Center near Cape Canaveral, Florida, for launch from launch complex 39A on a SpaceX Falcon 9 vehicle.

Building IXPE during a Pandemic

A collaboration between NASA Marshall and the Italian Space Agency (ASI), IXPE consists of three identical X-ray telescopes, each containing a set of nested cylinder-shaped mirrors — known as "grazing incidence" mirrors — paired with a corresponding polarization-sensitive detector. IXPE's polarization measurements are made possible by new detector technology contributed by ASI. Marshall's responsibility was to build and calibrate the mirror assemblies and deliver them to Ball for assembly, integration, and environmental testing.

"As an international project, the IXPE team faced a lot of unexpected challenges in the face of the COVID-19 pandemic," said Janice Houston, lead systems engineer at Marshall. "To get here has really taken a lot of teamwork and working through challenges. We have learned a lot about overcoming logistical difficulties — how to ship the hardware from one place to another during lockdown and how to remotely supervise and monitor handling and testing."

In order to keep team members safe and healthy, NASA delayed assembly and calibration of IXPE's mirror modules in mid-March, 2020. The IXPE team developed a new schedule to allow the team to reorder its assembly and testing timeline and get the spacecraft ready for launch.

The mirror assemblies left Marshall the afternoon of Sept. 9, arriving at Ball on Sept. 10 to be integrated into the spacecraft. Under normal circumstances, Marshall's mirror module assembly team would help unpack and inspect the mirror modules after shipment. Instead, the team provided Ball with written procedures and video demonstrating post-shipment inspection, resulting in a successful integration.

With integration complete, IXPE will undergo environmental testing at Ball. Though each component of the observatory has been rigorously tested during development, demonstrating that the assembled flight hardware is able to safely pass through a simulated launch environment will be another significant achievement for the mission. NASA has worked carefully with its international partners to match the testing environment precisely to what IXPE will experience both on launch day, and when operating in orbit.

More about IXPE

NASA selected IXPE as a Small Explorer mission in 2017. IXPE is a collaboration between NASA and the Italian Space Agency, led by principal investigator Martin Weisskopf at NASA's Marshall Space Flight Center in Huntsville, Alabama. Ball Aerospace, headquartered in Broomfield, Colorado, manages spacecraft operations with support from the University of Colorado at Boulder. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the Explorers Program for the agency's Science Mission Directorate in Washington.