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

Technology Responsivity
and Risk Mitigation
Optimizing the
Programmatic S/N
Of Future Large
Space Telescopes
Astrophysics 2020
Large Space Missions Beyond the Next Decade
Astrophysics 2020 11/07
Dan Lester
University of Texas
Nov 2007
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.
=?
+
Astrophysics 2020 11/07
Programmatic Considerations for Future Investments
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
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
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 H2 ; first structure
Cosmic history of star formation
and nucleosynthesis
Fossil remnants of solar systems
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
Vision Mission architecture c.2003
Identified in 2000 Decadal
community prioritization as a
primary Vision Mission
(also FAIR, DART, etc.)
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CALIPSO architecture
(a new JPL concept)
CALISTO IS a SAFIR!
4x6 off-axis primary; fits easily in ELV
Astrophysics 2020 11/07
Also of note in this context …
SPICA
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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.
Perhaps a precursor to a SAFIR/CALISTO design?
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.
Astrophysics 2020 11/07
Is NASA Interested in these Opportunities?
• 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.”
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HST model
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
Astrophysics 2020 11/07
Servicing Venues
Table 1 Description of possible human space assets that might participate in integration and test activities
HUMAN
PLATFORM
CEV with EVA
CEV with no
EVA
Dedicated and
permanently
manned
service center
Dedicated
service center
with occasional
human
presence
No gateway or
CEV support
for testing
LOCATION
LEO
EM L1
Cis-lunar
LLO
ES L2
Considerable influence
Most benign of the
Might be used
Persistent thermal
Eventual
from gravity and thermal
options with respect
during transit of the
and gravity effects.
operational
shadowing by Earth
to gravity and
observatory to ES
location of
thermal disturbance
L2
most systems.
effects.
This is the Hubble model.
Most likely location
Possible since this is Very likely,
[A]
[B]
the path to be taken
depending on lunar
to the Moon.
surface activity.
Requires tugs, agile arms or other construction hardware. Robotic or telerobotic systems could be
employed, under the control of humans.
A surrogate for International Most likely location
Unlikely since no
Proposed by many
Space Station. A possible
permanent human
architecture studies.
Excluded due
replacement for the CEV
asset is expected in
Would also be a
to Astronaut
options, but only if
this location
depot for fuel and
safety
contamination issues can
other consumables..
concerns.
be addressed. [A]
Like CEV, but would be
Most likely location
Possible but is
Considerable
larger and not equipped to
energetically
energy penalty to
leave LEO. Also, will be
inefficient because
get to L2
smaller than ISS for cost
substantial
reasons. [A]
propulsion is needed
to maintain position.
Testing resources must be embedded in the observatory or testing resources brought to the observatory by CEV or
autonomous precision navigation. Probably precludes human roles.
EM L1 advantageous
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Servicing Venues
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.
Adapted from Decadal Planning Team documents
… and, for many reasons, Earth-Moon Lagrange
points are enabling for Exploration of the Moon.
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Notional SAFIR Servicing Mission Design
Earth-Sun L2
SAFIR does
low delta-V
return to L1
SAFIR does
low delta-V
return to L2
Earth-Moon L1
CEV does
L1 insertion
Rendezvous
& service
Service
Module
Expended
CEV on Ares IV
SAFIR on
Ariane V or equiv
Low Earth Orbit
Direct Entry
Land Landing
EARTH
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Servicing Strategies 1
J. Budinoff GSFC
Orion CEV approaches a VM SAFIR at Earth-Moon L1.
CEV will dock to it on LIDS-compatible interface.
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Servicing Strategies 2
J. Budinoff GSFC
J. Budinoff GSFC
Service enabled by teleoperated deployable crane (under study by
CxPO), with depressurization EVA for hands-on supervision.
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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
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CLV Options - A New Paradigm?
Heavy-lift, large payload volume options for
lofting BIG, DEPLOYED (~8-10m) or
UNDEPLOYED (>20m?) telescopes.
12m diam
shroud option
10m baseline
If a CLV is going to
be developed,
astronomers should
be thinking outside
the box.
Ares 5
HST
25mt
to LEO
125mt
to LEO
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CLV Options - A New Paradigm?
CLV Options - A larger SAFIR?
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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!
Astrophysics 2020 11/07