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

[LouScheffer]

[Writing about Falcon Heavy]

I have only one note about the news coverage.  Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s.   That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit.  All of that thrust is neat, but much of it is not being used for the actual payload mission.

Here is an even more extreme example.   A Falcon 9 can put about 23,000 kg into LEO, but here is being used to launch a 320 kg or so satellite, about 1/60 of its max payload.  Some of that extra performance is used for the plane change, but more importantly some is used for recovery, which reduces the cost

From this example, it's clear re-usability has largely decoupled launch mass and cost.   Here SpaceX is using a 550 tonne rocket to do the same job that can be done by a 20 tonne Pegasus.   Despite massing 27 x as much, it's cheaper - $50M vs $56M.

If you do the comparison in terms of dry mass expended, then it's much closer.   Assuming the fairings can be recovered, Spacex will expend about 4.5 tonnes of hardware.  Pegasus would expend about 2 tonnes, assuming a 90% mass fraction.  This brings the ratio of cost per expended hardware into the range that can be explained by system complexity, launch frequency, volume production, etc.

[envy887]

[Writing about Falcon Heavy]

I have only one note about the news coverage.  Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s.   That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit.  All of that thrust is neat, but much of it is not being used for the actual payload mission.

Here is an even more extreme example.   A Falcon 9 can put about 23,000 kg into LEO, but here is being used to launch a 320 kg or so satellite, about 1/60 of its max payload.  Some of that extra performance is used for the plane change, but more importantly some is used for recovery, which reduces the cost

From this example, it's clear re-usability has largely decoupled launch mass and cost.   Here SpaceX is using a 550 tonne rocket to do the same job that can be done by a 20 tonne Pegasus.   Despite massing 27 x as much, it's cheaper - $50M vs $56M.

If you do the comparison in terms of dry mass expended, then it's much closer.   Assuming the fairings can be recovered, Spacex will expend about 4.5 tonnes of hardware.  Pegasus would expend about 2 tonnes, assuming a 90% mass fraction.  This brings the ratio of cost per expended hardware into the range that can be explained by system complexity, launch frequency, volume production, etc.

If we're trying to track reuse and dollars, Pegasus has a liftoff mass of about 200 tonnes. That L-1011 first stage isn't free. That puts it in the same expended dry mass fraction ballpark as Falcon 9 at roughly 2 t / 200 t or 1% of liftoff mass, and roughly 1/2 of the liftoff mass of Falcon. Manufacturing and operational efficiencies, and flight rates account for the rest of the difference in cost.

Falcon gets a lot more payload per liftoff mass because it uses higher energy fuel, has better mass fractions, and stages more optimally.

[gongora]

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.

[envy887]

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.

That's a lot less than $50.3 million...

[speedevil]

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 it plausible there may be other launch services under another number?

[Zed_Noir]

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 it plausible there may be other launch services under another number?

Wonder if the launch service order include mission assurance paperwork?

[Confusador]

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 it plausible there may be other launch services under another number?

Wonder if the launch service order include mission assurance paperwork?

I'm now trying to parse this bit of the PR (emphasis added):

The total cost for NASA to launch IXPE is approximately $50.3 million, which includes the launch service and other mission-related costs.

I was assuming that the "five (5) Mission Unique Services" were the "mission-related costs", but now I'm wondering what they are, and if they're even for services provided by SpaceX.

Edit: I'm assuming that the cost of the payload itself is accounted elsewhere, but this could be payload processing before handover?  Or the cost of payload operations during launch?

[gongora]

The mission unique services in the SpaceX contract would be for things SpaceX is providing.  I don't see any easy to find list of such services for NLS II, but for the DoD contracts it's stuff like extra analysis, extra maneuvers, extra acoustic or RF shielding in the fairing, extra cooling in the fairing, extra access panels in the fairing, purging with nitrogen instead of just filtered air, extra power or data channels to the payload, extra separation events, integrating secondary payloads, performing extra mission rehearsals, etc.

[Chris Bergin]

https://www.nasaspaceflight.com/2019/07/ball-design-review-ixpe-spacex-contract-growing-profiles/

- By Ian Atkinson with an overview of the spacecraft and the award.

https://twitter.com/NASASpaceflight/status/1155922631604019201

[speedevil]

Minor nit.

IXPE will be NASA’s newest X-ray telescope – its first since NuSTAR, which launched on a Pegasus rocket in June 2012.

Neutron-star Interior Composition ExploreR (NICER) which launched on CRS-11 in 2017 is an X-ray telescope too..

It is a somewhat different design, focused on different things.

[Comga]

Also the 30 degree resolution is a typographical error.
If memory serves it is a 30 Arc-second angular resolution
I don’t know the resolution on the polarization vector, which is also important.
I believe the Field-of-View is 15 arc-minutes, not 11 degrees.
Each of these numbers needs to be checked, which I cannot do now.

[IanThePineapple]

Thanks for the corrections, I kept reading ' and " as °.

And I totally forgot about NICER, I was only thinking about free-flying observatories.

[kaa]

Thanks for the corrections, I kept reading ' and " as °.

And I totally forgot about NICER, I was only thinking about free-flying observatories.

NICER isn't really a telescope. It has single-reflection concentrators so doesn't produce an image. Both NuSTAR and IXPE use two reflections so produce images, which is what we usually mean by a telescope.

[smoliarm]

The mission unique services in the SpaceX contract would be for things SpaceX is providing.  I don't see any easy to find list of such services for NLS II, but for the DoD contracts it's stuff like extra analysis, extra maneuvers, extra acoustic or RF shielding in the fairing, extra cooling in the fairing, extra access panels in the fairing, purging with nitrogen instead of just filtered air, extra power or data channels to the payload, extra separation events, integrating secondary payloads, performing extra mission rehearsals, etc.

Some speculation on possible nature of the mission unique services here, for IXPE.

Personally I never had experience with high-sensitivity gamma-detectors, only the regular military type things (which are very simple and chemically stable). But I heard that going to sensitivity levels 1K - 10K higher, one must employ VERY exotic compounds for sensors, which are typically very susceptible to common things like atmospheric moisture, oxygen and CO2.
One more thing I heard - some type of high-sensitivity gamma-detectors can not tolerate even traces of common motor oil in air (or anything which contains sulfur in form of -SH group). Because even microscopic amount of sulfur in this form would *kill* the sensor.

So my guesses would be
a) to provide "specially purified" air in the assembly hall along with special clothing etc.
and/or
b) to provide continuous purging (or pressurization) of sensor "box" with high-purity grade nitrogen (or another suitable gas)

[speedevil]

Thanks for the corrections, I kept reading ' and " as °.

And I totally forgot about NICER, I was only thinking about free-flying observatories.

NICER isn't really a telescope. It has single-reflection concentrators so doesn't produce an image. Both NuSTAR and IXPE use two reflections so produce images, which is what we usually mean by a telescope.

It's very much a telescope - many interesting sources are only single pixel anyway.
At the least, it probably deserves a mention.

[Comga]

Thanks for the corrections, I kept reading ' and " as °.

(Snip)

De nada

As for Ball Aerospace spacecraft, they run from the seven (or eight) Orbiting Solar Observatories in the 60’s and 70’s, through Deep Impact, the early WorldView spacecraft, and the NPOESS Preparatory Program (NPP), to the highly relevant Green Propellant Infusion Mission (GPIM) on STP-2 that shares many spacecraft subsystems with IXPE.

[OneSpeed]

Compared to Falcon 9’s regular payloads, IXPE is very small. Weighing in at approximately 320kg, it will make for an easy mission for the workhorse rocket. Due to its low mass and orbit, this mission could likely feature a Return-to-Launch-Site (RTLS) landing of the first stage at SpaceX’s Landing Zone 1. However, this depends on both the flight profile and how much extra performance margin NASA requests.

I'd say RTLS for IXPE is unlikely. IXPE is designed for Pegasus' maximum acceleration of around 9 gees, but with such a light payload, the Falcon 9 second stage will need to be ballasted to limit acceleration to the same range. Using the Starlink launch profile, there is about 3t of S2 propellant left over after the combined plane change and circularisation burn, which is just enough to limit acceleration to about 8 gees.

[Targeteer]

http://lasp.colorado.edu/home/missions-projects/quick-facts-ixpe/?fbclid=IwAR1CYjF5xBZxCOrqljjO4i2cYXPLHdv8Gv8tKDUvTYj8OhlnLjpZC91WBUw


Quick Facts: Imaging X-ray Polarimetry Explorer (IXPE)

IXPE will expand the X-ray view of the universe as it opens new dimensions for exploring how x-ray emissions are produced under extreme physical conditions near objects such as neutron stars and black holes. (Courtesy NASA/MSFC)
Mission Introduction

Objects such as black holes can heat surrounding gases to more than a million degrees. The high-energy X-ray radiation from this gas can be polarized—vibrating in a particular direction. The Imaging X-ray Polarimetry Explorer (IXPE) mission will fly three space telescopes with cameras capable of measuring the polarization of these cosmic X-rays, allowing scientists to answer fundamental questions about these turbulent and extreme environments where gravitational, electric, and magnetic fields are at their limits.

IXPE will improve sensitivity over OSO-8, the only previous X-ray polarimeter, by two orders of magnitude in required exposure time. IXPE also will introduce the capability for X-ray polarimetric imaging, uniquely enabling the measurement of X-ray polarization with scientifically meaningful spatial, spectral, and temporal resolution, to address NASA’s goal “to probe the origin and destiny of our universe, including the nature of black holes, dark energy, dark matter, and gravity.” IXPE measurements will provide new dimensions for probing a wide range of cosmic X-ray sources—including active galactic nuclei (AGN) and microquasars, pulsars and pulsar wind nebulae, magnetars, accreting X-ray binaries, supernova remnants, and the Galactic center.

Science Objectives
IXPE’s polarization measurements will help answer fundamental questions that impact and advance high-energy astrophysics, including:

    What are the geometries of the flows, emission regions, and magnetic fields?
    What physical processes lead to particle acceleration and X-ray emission?
    What are the physical effects of gravitational, electric, and magnetic fields at their extreme limits?

LASP Roles

LASP will provide:

    Mission operations for IXPE

LASP Instruments

LASP will not provide any instruments for the IXPE mission.
Quick Facts

Launch date: NET November 20, 2020
Launch location: Kwajalein, Marshall Islands
Launch vehicle: Pegasus
Mission target: 540-km circular Earth orbit
Mission duration: Two-year primary mission

Other organizations involved:

    NASA Marshall Space Flight Center (MSFC)
    Ball Aerospace and Technologies Corporation
    Italian Space Agency (ASI)
        Institute for Space Astrophysics and Planetology
        National Institute for Astrophysics

[gongora]

NASA LAUNCH SERVICES II - SPACE EXPLORATION TECHNOLOGIES. This is a bilateral modification to add a mission unique service (MUS) for a transient voltage suppression system on the Imaging X-Ray Polarimetry Explorer (IXPE) launch service task order.

[gongora]

NASA SMSR schedule shows this as May 31, 2021.