1. Astrophysics 2020 11/07 Technology Responsivity and Risk Mitigation Optimizing the Programmatic S/N Of Future Large Space Telescopes Dan Lester University of Texas Nov 2007 Astrophysics 2020 Large Space Missions Beyond the Next Decade

2. Astrophysics 2020 11/07 Most astronomical telescopes, requiring exquisite cleanliness and thermal control are better in free space than on the lunar surface. But investment in returning to the Moon compels us to consider their relationship to the Exploration initiative. + = ?

3. Astrophysics 2020 11/07 Mitigating risk -- can we service future space telescopes and fix them? Technology responsivity -- can we respond to new technologies that advance the power of future space telescopes? Programmatic S/N? -- Large investments create huge scientific “signal” Inaccessibility lowers the effectiveness of that signal. Disposable telescopes may not be the right approach. Let’s consider this from perspective of IR space astronomy Programmatic Considerations for Future Investments

4. Astrophysics 2020 11/07 The Single Aperture Far Infrared Observatory Concept : Filling Key Gaps Large primary mirror baseline 6+ meters Cold optics; zodi/confusion/CMB background limits <<10K High performance focal plane FIR sensors

5. Astrophysics 2020 11/07 The SAFIR Concept -Targeting Priority Science IR telescopes offer visibility into the most obscured parts of our universe … revealing the birth of stars and planetary systems, as well as tracers of the molecular chemistry of life. Primordial H 2 ; first structure Cosmic history of star formation and nucleosynthesis Fossil remnants of solar systems

6. Astrophysics 2020 11/07 The SAFIR Mission Concept - flowdown to architectures new folding strategies new cooling strategies ops basing at Earth-Sun L2 autonomous deployment lifetime presently limited by instrument technologies Identified in 2000 Decadal community prioritization as a primary Vision Mission (also FAIR, DART, etc.) Vision Mission architecture c.2003 CALIPSO architecture

7. Astrophysics 2020 11/07 (a new JPL concept) CALISTO IS a SAFIR! 4x6 off-axis primary; fits easily in ELV

8. Astrophysics 2020 11/07 Also of note in this context … Perhaps a precursor to a SAFIR/CALISTO design? SPICA Takao Nakagawa, PI (ISAS / JAXA) Size: 3.5 m (No Deployment) Temperature: COLD (4.5 K) Orbit: L2 Halo Lifetime: 5 years + Launch: ~2017 by HIIA-202 A major international mission ESA funding a Cosmic Visions study in Europe for contribution of telescope + instrument US group proposing a sensitive spectrograph (BLISS) using new far-IR detectors which point to CALISTO / SAFIR.

9. Astrophysics 2020 11/07 What Could the Exploration Initiative Potentially Offer Astronomy? Let’s not go there if there isn’t value to be gained! Servicing (human or robotic) for big science investments. - instrument upgrades ; follow steep technology trajectory - lifetime extension ; subsystem replacement, retanking - increased risk tolerance - enabling assembly/deployment for largest systems Launch vehicles with new payload capabilities We do this now with Hubble Space Telescope, though future value will depend on non-science drivers for architecture.

10. Astrophysics 2020 11/07 ESMD is funding efforts to develop concepts for in-space operations with Exploration architecture. The Astrophysics Subcommittee of the NASA Advisory Council concluded at the 3/07 Tempe “Workshop on Science Associated with the Lunar Exploration Architecture” that high priority technologies include “In-Space Operations - potential for assembly, servicing, and deployment (trade studies)” “Large launch vehicle capabilities - VSE will include large launch vehicles like Ares V, and the community should be part of a dialog in crafting its capabilities.” Is NASA Interested in these Opportunities?

11. Astrophysics 2020 11/07 Servicing Functionalities replace focal plane science instrument + replacement offers new science opportunities (wavelength coverage, resolution, etc.) + replacement offers obsolescence mitigation (new sensor technology) replace spacecraft systems as needed + recover solar panel power output degraded by solar UV + batteries replace solar shield as needed + recover performance of shield as degraded by micrometeorite penetrations & solar irradiance retank stationkeeping propellants & other consumables HST model

12. Astrophysics 2020 11/07 Servicing Venues EM L1 advantageous

13. Astrophysics 2020 11/07 Servicing Venues Adapted from Decadal Planning Team documents While Earth-Sun L2 is optimal ops location for many telescopes, Earth-Moon L1 is a nearby jobsite to which transit back and forth is easy. Earth-Moon L1 is 84% of the way to the Moon, semi-stable, accessible to lunar-capable human space program, and offers low latency to Earth for telerobotic efforts. … and, for many reasons, Earth-Moon Lagrange points are enabling for Exploration of the Moon.

14. Astrophysics 2020 11/07 Notional SAFIR Servicing Mission Design CEV on Ares IV CEV does L1 insertion Earth-Moon L1 Low Earth Orbit Service Module Expended EARTH Direct Entry Land Landing Earth-Sun L2 SAFIR does low delta-V return to L1 SAFIR on Ariane V or equiv Rendezvous & service SAFIR does low delta-V return to L2

15. Astrophysics 2020 11/07 Servicing Strategies 1 Orion CEV approaches a VM SAFIR at Earth-Moon L1. CEV will dock to it on LIDS-compatible interface. J. Budinoff GSFC

16. Astrophysics 2020 11/07 J. Budinoff GSFC Servicing Strategies 2 Service enabled by teleoperated deployable crane (under study by CxPO), with depressurization EVA for hands-on supervision. J. Budinoff GSFC

17. Astrophysics 2020 11/07 Servicing Strategies - Trades Contamination mitigation -- warmup strategies? + UV polymerization of propellant hydrocarbons + freezeout of CEV waste dumps and outgas + post-service bakeout? CEV service module payload capabilities? + teleoperated crane, service subsystems + trade payload, astronaut complement Lunar module as docking port for CEV? + dust contamination issues Post-service performance testing at EM L1? Robotic only? + Lessons from Hubble study, though with compliant target + Lessons from Orbital Express

18. Astrophysics 2020 11/07 Heavy-lift, large payload volume options for lofting BIG, DEPLOYED (~8-10m) or UNDEPLOYED (>20m?) telescopes. 25mt to LEO 125mt to LEO 12m diam shroud option 10m baseline HST Ares 5 CLV Options - A New Paradigm? If a CLV is going to be developed, astronomers should be thinking outside the box.

19. Astrophysics 2020 11/07 CLV Options - A New Paradigm? CLV Options - A larger SAFIR?

20. Astrophysics 2020 11/07 The Exploration initiative will be developing capabilities to do things that can be enormously enabling to astronomy. We are challenged to come up with mission concepts that explore … servicing (human or robotic) deployment / telescope assembly (human or robotic) large mass/volume lift capabilities … and encourage NASA to consider them!