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Astronomy 4800 – Space Science: Practice & Policy

ASTR 4800 - Space Science: Practice & PolicyToday: Can we afford Astrophysics Flagship Missions?: JWST & WFIRST

– Next Class on Dec. 2 at the Fiske Planetarium: Einstein and Interstellar Travel.

– Reading: article referenced on class webpage for Dec. 2.

Astronomy 4800 – Space Science: Practice & Policy

Space in the News: Space exploration and nuclear proliferation

Presenter : Jeremy Schlagel

NASA is proposing to develop a reactor called Kilopower that could be ready to support lunar bases in the latter half of the 2020s, but the choice of fuel for that reactor worries nuclear nonproliferation experts.

Can We Afford Astrophysics Flagship Missions?

JWST and WFIRST

Presenters: Alex Baughman and Colin Brown22 November 2019

What are “Flagship” Missions?- Large missions, typically

costing upwards of $1 billion

- Exist in Astrophysics, Earth science, Heliophysics, and Planetary Science

- JWST and WFIRST fall into Astrophysics category

- Other similar missions: Hubble Space Telescope, Chandra X-ray Observatory, Kepler, TESS

JWST and WFIRSTJWST WFIRST

Location L2 L2

Projected Cost $10 Billion $3.2 billion

Projected Launch March 2021 2025

Lifespan (years) 5 (design), 10 (goal) 5 (design)

Goals ● Use infrared to study

origins of the galaxy and

universe

● Study exoplanets for

building blocks of life● Learn more of our own

solar system

● Large field of view

images with high

precision and accuracy

● Address questions for

dark energy and exoplanets

Beginning of Development 1996 2010

Brief History of JWST Program- 1990’s

- In the 1991 Astrophysics Decadal Survey:- Strong emphasis on using infrared light to study distant galaxies - General consensus to build a larger, more powerful space telescope

- Led to the Next Generation Space Telescope in 1996- Estimated to cost $500 million and launch in 2007

- 2000’s- Renamed to James Webb Space Telescope- Project was re-planned in 2005; updated budget of $4.5 billion- Launch date continually pushed back: 2007->2011->2015->2020->2021

- 2010’s- Final construction finished in 2016- Multiple testing failures have delayed things further- Current estimate (Oct. 2019) - $10 billion, launch in 2021

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What / Where is L2?- What are Lagrange Points?

- Essentially a 3-body gravitational problem- Point where the gravitational pull of two

larger bodies equals the centripetal force on a smaller body (i.e. spacecraft)

- This allows the smaller object to maintain its relative position with the two other bodies

- Why L2?- Clear view of deep space- Close enough for communication with

Earth (~1.5 million km)- Can still receive solar power via halo orbit- Relatively stable orbit (~23 days)

James Webb Space Telescope (JWST)- Pros v cons:

- Pros: - Potential for new science discoveries- New technologies developed which could be used for future space

telescopes

- Cons: - Cost- Schedule- Risk of failure

Pros: Science Discoveries- Infrared vision can look over 13.5 billion years into the

past- Understand how first stars and galaxies formed- Comparison with our own current galaxy will help to

understand evolution of the Milky Way

- Ability to see through heavy clouds of dust- Allow us to see other stars and planetary systems that could not

be seen by Hubble

- Observation of the atmospheres of exoplanets- Help us better understand the planet/atmospheric compositions- Potentially find building blocks of life across the universe

- Ability to better study objects in our own solar system

Pros: Notable New Technologies Developed- Infrared detectors

- Near-infrared and mid-infrared

- Sunshield- Tennis-court sized- Five human-hair thick layers to reflect sun’s heat

- Cryocooler/Cryogenic DAQ- To suppress background heat generation from the payload- DAQ is able to convert A-D at extremely low temperatures

- Backplane/Lightweight hexagonal folding mirrors- Large area to collect more light (~6.5 meters across)- Aligned to 1/10,000 of a human hair

Cons: JWST Cost and Schedule Over the Years- In 2011, congress proposed to

cancel the project- Proposed a $1.9 billion cut from

NASA’s total budget

- The American Astronomical Society and Senator Barbara Mikulski voiced support for the program

- Congress agreed to reverse cancellation and instead cap program at $8 billion

- How can we better manage a mission such as this?

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Cons: Mission Risk- With L2 point being 1.5 million km from Earth, it is incredibly difficult to reach

- Designed to be unserviceable

- For reference, Hubble experienced a serious issue within weeks of its launch:- Primary mirror was polished to the wrong shape on outer perimeter- Required collectively 5 spacewalks of over 35 hours to replace 10 instruments and fix the mirror

- Deployment of JWST:- https://www.youtube.com/watch?v=vpVz3UrSsE4

- Incredibly small tolerances, particularly on mirror alignment- What do we do/what CAN we do if something goes wrong?

JWST Summary- Lots of great science to be done

- Learn a great deal about the formation of our galaxy and uncover unknowns of the universe- Potentially discover traces of life on exoplanets

- But is the science worth it?- Poorly managed, inflating costs and schedule- Unforeseen, yet routine setbacks that were not accounted for in schedule margin- Why was the project not shut down?- How much are taxpayers willing to tolerate for large, important flagship missions like JWST?- Just this week, NASA’s Science Mission Directorate hinted towards even FURTHER delays

Class DiscussionWhat will happen if the JWST experiences a major failure at L2? How would this affect future flagship Astrophysics missions?

Wide Field Infrared Survey Telescope (WFIRST) WFIRST OverviewScience Goals

● Attempt to answer questions in areas of dark energy, exoplanets, and infrared astrophysics

● Will have panoramic field of view 100x greater than Hubble

Logistics

● Planned 2025 launch● Projected cost of $3.2 billion● 5 year lifespan

Unusual History

● #1 mission for 2010 Astrophysics decadal survey○ Combination of multiple white papers with similar concepts to produce a “broadly capable

mission”■ Never been done before for a decadal survey■ Essentially went against decadal survey procedures to create this project

○ Multiple design changes from conception

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WFIRST Science● Primary mirror is 2.4 m in diameter

(same as Hubble)● Two on-board instruments:

○ Wide Field Instrument■ Enables larger portion

of sky to be imaged (100x greater than Hubble)

○ Coronagraph Instrument■ Blocks direct light from

stars to resolve nearby objects (exoplanets)

Comparison to Hubble

Coronagraph

WFIRST Science Cont.● Wide Field Instrument

○ Provides stable observations for implementing the Dark Energy, Exoplanet Microlensing, and Near Infrared surveys.

● Coronagraph Instrument ○ Part-per-billion suppression of

starlight to enable the detection of planets smaller than Mars, orbiting at distances closer than Venus to their host stars

Dark energy distribution

Exoplanet Microlensing

WFIRST History● The EOS panel of the Astro 2010 Decadal Survey created WFIRST by combining the science proposed by

several similar hardware concepts (i.e.; JDEM-Omega, MPF, and NIRSS; all wide field, near-infrared telescopes)

● NASA HQ formed a Science Definition team in late 2010 to perform a two year study to develop a Design Reference Mission (DRM) responsive to the NWNH report.

2010 2011 2012

JDEM-Omega (2010)● 1.5 m obstructed

telescope● 3-channel payload-

H2RG’s● 5 year mission● Atlas V launch

vehicle● Estimated $1.21 B

WFIRST-IDRM (2011)● 1.3 m unobstructed

telescope● 3-channel payload-

H2RG’s● 5 year mission● Atlas V launch

vehicle● Estimated $1.63 B

WFIRST-DRM 1 (2012)● 1.3 m unobstructed

telescope● 1-channel payload-

H2RG’s● 5 year mission● Atlas V launch

vehicle● Estimated <$1.6 B

WFIRST-DRM 2 (2012)● 1.1 m unobstructed

telescope● 1-channel payload-

H4RG’s● 3 year mission● Falcon 9 launch

vehicle ● Estimated $945 M

WFIRST Funding Year Funding

(millions)

Comments

2014 $56 Project study / Conceptual designs

2015 $50 Estimated total cost of $2 billion

2016 $90 Entered “formulation phase” i.e. officially became a NASA mission

2017 $105 Independent review projected $3.9 billion for total cost

2018 $127 WFIRST de-scoped to $3.2 billion

2019 $312 Presidential budget proposed to cancel WFIRST, denied by Congress

2020 $542

(NASA requested)

Again, Presidential budget proposes to cancel / delay WFIRST

Projected

Total Cost

$3.2 billion Currently on track for 2025 launch, $3.2 billion cost, unless funding declines

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WFIRST Funding and Recent Status● Proposed to be cancelled in President’s

FY19, Congress passed bill in 2018 to continue its funding○ Congress "rejects the cancellation of

scientific priorities recommended by the National Academy of Sciences decadal survey process"

● President’s FY20 budget proposed to delay WFIRST to focus on JWST○ Should we wait for JWST to finish

before going forward with WFIRST? ● PDR concluded Nov 1st, 2019, but still

awaiting formal mission confirmation in early 2020○ Say they’re on track but current

proposed Senate budget threatens to delay it further

WFIRST Summary

Pros Cons

● “Best of both worlds” i.e. large field of view + precise measurements

● Advance science in areas of dark energy, exoplanet detection, and near infrared surveys

● “Design-to-cost” instead of “Design-to-mission-success”○ Says they’re on schedule

(2025) and within budget ($3.2 billion)

● Is the science worth the total cost? Can we do the same science differently?

● Like JWST, located at L2 so difficult to repair if something goes wrong

● Combination of white papers, mission thrown together without much preparation

● Uncertain future

Class DiscussionIf we invest all this time and money into flagship missions, should we cancel one if it’s taking too long or too much money?

Flagship Missions: Final Thoughts● Are Flagship missions becoming too large?● How much are we willing to spend?● Are we getting a good return on our investments?● What are we not able to spend money on because of these

missions?● Is there a different way to do the same science?

Referenceshttps://www.jwst.nasa.gov/

https://wfirst.gsfc.nasa.gov/

https://www.nasa.gov/sites/default/files/atoms/files/wietr_final_report_101917.pdf

https://wfirst.gsfc.nasa.gov/science/sdt/meetings/2012_Nov/MMelton.pdf

https://solarsystem.nasa.gov/resources/754/what-is-a-lagrange-point/

https://www.aip.org/fyi/2016/nasas-large-strategic-science-missions-under-microscope

https://web.archive.org/web/20081110180605/

http://www7.nationalacademies.org/bpa/CAA_Nov2005_Presentation_Mather.pdf

https://www.nap.edu/nap-cgi/skimchap.cgi?recid=1634&chap=72-90

https://www.skyandtelescope.com/astronomy-news/james-webb-telescope-launch-delayed-until-2020/

https://www.theguardian.com/science/2011/jul/09/nasa-james-webb-space-telescope

https://hubblesite.org/mission-and-telescope/mission-timeline#h4-4ba19dbc-c864-47fd-9056-ff82666b149f

https://www.forbes.com/sites/startswithabang/2017/04/05/how-much-gold-is-in-the-james-webb-space-telescope/#77d6285769e5

https://astronomynow.com/2017/05/09/james-webb-space-telescope-shipped-to-texas-for-its-biggest-test-yet/

https://wwwastro.msfc.nasa.gov/lynx/docs/documents/hertz-astro2020-kickoff-slides.pdf