MinXSS web site�http://lasp.colorado.edu/home/minxss/

Tom Woods

& the MinXSS CubeSat Team

University of Colorado, LASP

tom.woods@lasp.colorado.edu

The MinXSS CubeSats

MinXSS (pronounced like minks) = Miniature X-ray Solar Spectrometer

🡨 Minks the animal – small mammal known for its soft fur

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Topics

Miniature X-ray Solar Spectrometer (MinXSS)

​

• Background and History of MinXSS Missions
• MinXSS CubeSat Enabling Technology
• MinXSS Science Highlights
• MinXSS Missions / Status
• MinXSS-1 (ISS deployment)
• MinXSS-2 (SSO)
• MinXSS-3 = DAXSS MoO on InspireSat-1 (SSO)

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MinXSS Mission Background

• A University of Colorado (CU) graduate student project initiated a new CubeSat mission concept in 2012. It initially had focus on studying the far ultraviolet (FUV) emissions of the thermosphere (aurora).
• The data volume for FUV imaging was too large for UHF communication, so the focus changed in 2013 to studying the solar soft X-ray (SXR) emissions, which are key energy input for the ionosphere.
• This mission called the Miniature X-ray Solar Spectrometer (MinXSS) was proposed to NASA and selected in 2014.

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MinXSS 1-3

• 3U CubeSat to study the solar soft X-ray (SXR) spectra
• Developed as CU student project and funded by NASA
• MinXSS-1 mission: 2016-2017
• MinXSS-2 mission: 2018-2019
• MinXSS-3 (DAXSS): 2022-now

Tom

Woods

Andrew

Jones

Rick

Kohnert

Scott

Palo

Harry

Warren

Amir

Caspi

Stan

Solomon

Phil

Chamberlin

James

Mason

PhD 4/16

Chris

Moore

PhD 12/17

Robert

Sewell

MinXSS Co-Is

& PhD

Students

Bennet

Schwab

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MinXSS-1 Mission Highlights

• MinXSS-1 was launched in December 2015 and deployed from the ISS in May 2016. It re-entered in May 2017.
• MinXSS is first CubeSat science mission for the NASA Science Directorate.
• Many technology demonstration CubeSat missions had been flown by NASA.
• NSF started science CubeSat missions in 2008. One of them is LASP’s Colorado Student Space Weather Experiment (CSSWE, PI: Xinlin Li) that was launched in 2012 and provided strong heritage for MinXSS.

NSF’s CCSWE CubeSat in 2011

MinXSS CubeSat Prototype in 2014

Heritage from CSSWE

Student Project Structure

CubeSat System Engineering

CU/LASP UHF Ground Station

Spacecraft Subsystems

(EPS, CDH, COMM)

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MinXSS-1 Launch & Deployment

• Launch: Dec 6, 2015 on Atlas-V
• ISS Dock: Cygnus-4 docked with ISS on Dec 9
• ISS Deployment: May 16, 2016

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MinXSS Technology Highlights

• MinXSS-1 technology demonstration includes:
• Blue Canyon Technologies (BCT) Attitude Determination and Control System (ADCS)
• Innovative ADCS in 0.5U size with star tracker and capability for 10-arcsec 3-axis control
• MinXSS-1 flies first BCT XACT unit
• Amptek X123 X-ray Spectrometer
• Advanced X-ray detector for the solar observations
• 3-D Printed (sintered) Metal Parts
• Solar panel deployment hinges made with SS
• Solar Position Sensor (SPS) housing made with Al

BCT XACT (0.5U)

Amptek X123 (0.2U)

CU/LASP Deployment Hinge

CU/LASP SPS Housing

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MinXSS Exploded View of Subsystems

Volume

3U

Mass

3.51 kg

Power

Avg. 8.3W

Peak 25W

Acronyms: Command & Data Handling (CDH), Electrical Power System (EPS) with AzurSpace solar cells and sparkfun Li-poly battery, Communications (COMM, AstroDev Li-1 UHF Radio), Attitude Determination & Control System (ADCS, BCT XACT), Solar Position Sensor (SPS), X-ray Sensor (XS), X123 is Amptek X-ray spectrometer.

BLUE = Purchased

BLACK = Student Built

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MinXSS Science Highlights

• MinXSS Mission Goals:
• MinXSS-1: Understand the highly energetic solar flares in the soft X-ray (SXR) range and their impact on Earth’s ionosphere and thermosphere
• MinXSS-2 & -3: Understand the heating of active regions in the SXR range and solar forcing in ITM
• MinXSS has obtained solar SXR spectra for over 100 C-class and 8 M-class flares
• Analyses of those flare spectra reveal:
• large enhancements of corona temperature
• changes in the coronal elemental abundance
• MinXSS has provided new reference spectra for use in TIMED, SORCE, and SDO processing
• MinXSS provides calibration for GOES XRS

​

NSF’s CCSWE CubeSat in 2011

MinXSS

Spectra

MinXSS Time Series

GOES XRS TS

New AR

DEM

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MinXSS-2 Mission Highlights

• Improvements over MinXSS-1 (Mason et al., Adv Sp Res, 2020)
• Improved sensor: Amptek X123 SDD
• Extra UHF ground station at UAF
• Increased UHF rate to 19200 baud
• Added heat sink for Li-1 radio
• Added reset switch (uplink command)
• Flight software improvements
• MinXSS-2 was launched on 4 December 2018 as one of 64 small satellites on Spaceflight Industries SSO-A SmallSat Express (Falcon-9). MinXSS-2 was commissioned in 4 days.
• MinXSS-2 had SD-Card single event upset (SEU) on 7 January 2019. Resets have not been successful.
• Lesson Learned: (1) Increase Watchdog Timer from few seconds to few minutes; (2) Use more robust rad-tolerant FLASH for SSO
• MinXSS-2 has provided one month of quiet Sun spectra

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• DAXSS = Dual-zone Aperture X-ray Solar Spectrometer
• Amptek X123 SDD has higher energy resolution and larger dynamic range. DAXSS has innovative dual-zone aperture design to enhance the solar signal.
• Flown in June 2018 to provide calibrations as part of SDO EVE underflight calibration rocket payload. Reference: Schwab & Sewell et al., Ap J, 2020.
• Grad students Bennet Schwab and Robert Sewell converted rocket instrument into satellite instrument in 3 months after MinXSS-2 anomaly. DAXSS is integrated onto InspireSat-1 as flight of opportunity. Due mostly to COVID, IS-1 launch was delayed to February 14, 2022.

DAXSS – Improved Spectrometer for “MinXSS-3”

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MinXSS-3 Highlights

• DAXSS Improvements (Schwab et al., Ap J, 2020)
• Improved energy resolution (Amptek X123 SDD improvements)
• Enhanced signal levels (larger aperture, but saturates at ~M3)
• Extended energy coverage (use of Kapton filter with Be filter)
• InspireSat-1 has S-band capability (but not activated yet)
• InspireSat-1 was launched on 14 February 2022
• InspireSat-1 is on ESPA-like ring with rideshare on ISRO PSLV C-52 (PI: Amal Chandran; Chandran et al., Adv. Sp. Res., 68, 2616, 2021)
• DAXSS first-light was on 28 February 2022
• MinXSS team is collaborating with India’s Chandrayaan-2 Solar X-ray Monitor (XSM) science team
• InspireSat-1 prime mission is 6 months; plans for extended mission
• Solar cycle maximum activity has ramped up this spring
• Hundreds of flares since InspireSat-1 launch, but data downlink is currently limited by its UHF-only communication --- all of the DAXSS data are still on the IS-1 SD-card --- do you have any favorite flares to study?

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DAXSS Example Spectra

• DAXSS Level 1 Version 2 product has been released

Spectra down to 0.4 keV

ΔE = 0.06 keV @ 0.5 keV

Occultations provide thermosphere data

Terrestrial energetic particles are sometimes observed (~5% of the time)

MinXSS web site�http://lasp.colorado.edu/home/minxss/

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Summary

• MinXSS has been very exciting and successful project
• MinXSS has demonstrated key technology (e.g., BCT XACT, X123).
• MinXSS has provided higher resolution and calibrated solar soft X-ray (SXR) spectra and helped to fill the SXR gap.
• MinXSS has provided new results on flare energetics and revealed differences of coronal heating processes.
• MinXSS has provided new reference spectra important for modeling Earth’s atmosphere and calibration for GOES XRS.
• Key Reference Papers about MinXSS:
• MinXSS-1 Overview: Mason et al., J Spacecraft Rockets, 2016
• MinXSS-2 and Lessons Learned: Mason et al., Adv Sp Res, 2020
• Calibration Paper: Moore et al., SPIE 9905, 2017
• Solar Science Overview: Moore et al., Solar Phys, 2018
• MinXSS-1 First Light Paper: Woods et al., Ap J Lett, 2016
• DAXSS Instrument (MinXSS-3): Schwab & Sewell et al., Ap J, 2020
• InspireSat-1 (IS-1) Mission: Chandran et al., Adv Sp Res, 2021

MinXSS web site�http://lasp.colorado.edu/home/minxss/

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Flight Model #1

(FM-1)

FM-2

Protoflight

Model

Questions?

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