Kuafu
A mission to start a mission
William Liu
Canadian Space Agency &
Chinese Academy of Sciences
August 29, 2011, 3rd ILWS Science Symposium, Beijing
1
KUAFU IN A FEW WORDS
Same principles and equations
Different boundary conditions
Different solution
2
Solar Energy Output I = X
Magnetic field complexity results in
reconnection and particle ejection
in the solar corona, X
3
Solar energy input II = Y
Magnetic complexity also results in electromagnetic radiation (flares) , Y
4
Solar wind at 1 AU = Z
X (primarily) leads
to a variable solar
wind at 1 AU, Z
5
Magnetopause interaction = W
Solar wind condition Z leads
to variable interaction with the
magnetosphere at the magnetopause, W
Credit: University of Michigan
6
Energy deposition = U
Energy created through W is dissipated in the ionosphere
Credit: University of Alberta
7
Systems Question
Before, missions were focused on X, Y, Z, W, U, etc. individually
The System Question below is of great interest but seldom
simultaneously observed.
U = F1(W,Y)
W = F2(Z, U)
(feedback, cf., potential saturation)
Z = F3(X)
Fi is some time integral over the independent arguments
8
Kuafu: System science discoverer
24/7 simultaneous imaging
supported by high-resolution
in-situ observation focused on
kinetic-to-MHD scale physics
Kuafu A at the first Lagrangian point
Kuafu B in double Molnya orbit with 6 Re apogee
K-A imaging observation of X and Y
K-A in-situ observation of Z
K-B imaging observation of U
K-B in-situ observation of W
9
Kuafu A Imaging
Essential objective is to observe the entire
sequence of solar wind acceleration, with
special focus on the transition region
Lyman- imaging
of solar disk
Lyman- + whitelight
inner coronagraph
Whitelight outer
coronagraph
10
Generation of fast, slow solar wind & CME
• Deepen the knowledge of energy transport process
between the photosphere and corona; improve the
predictability of solar eruptive events
– What is the relationship between CMEs and motions and
magnetic field structures at the surface?
– What is the relationship between the energy carried by
CMEs and surface features?
– How are CMEs and other solar wind structures accelerated?
– What is the directionality of CMEs?
– What is the short-term variability of total solar-irradiance?
11
Kuafu B Imaging
12
Auroral Complexity
Arcs
Vortices
Turbulence
The morphology of U exhibits a high degree of complexity
13
12-h Molnya orbit
Stationarity and corotation with respect to a fixed point on Earth
63 inclination and 6 earth
radii apogee
Long dwell time over
ground networks on Earth
Year 0: long hover in the cusp
Year 0.5: long hover over
the nightside aurora region
14
Kuafu spacecraft
• Kuafu A
–
–
–
–
–
图五
示意图
夸父A卫星
3-axis stabilized satellite at L1
Total mass 722 kg
Payload 130 kg
Power: SOM 906 W; EOM 752 W
Downlink telemetry 350kpbs.
• Kuafu B (anticipated)
– Two 3-axis stabilized satellites in 12-h
Molnya orbit
– Mass: 1200 kg per satellite
– Science payload ~65 kg per satellite
– Power: ~80 W for science payload, 1 kW
overall, per satellite
– Downlink: ~ 2Mpbs.
15
WHAT NEW BOUNDARY CONDITION
• Canadian Space Agency cannot confirm anticipated
participation in Kuafu at this time (despite great
interest) due to government austerity measures
• European national agencies cannot provide the
majority of Kuafu instruments as originally planned
• Chinese Academy of Sciences insists that Kuafu be a
mission based on strong international collaboration
16
FIND NEW SOLUTION
• The international situation argues for
– Launch Kuafu A first (by 2016), with an enhanced in-situ
instrumentation from international sources
– Start immediately with a collaborative framework
committed to launching Kuafu B+ by 2019
– Search interim international collaborations with
concurrent missions (MMS, SWARM)
• This is riskier than we like, but the risk should be
balanced against the consequence of no Kuafu
– Certainty of failure is not better than possibility of success
• A sure winner
– Rename the mission iPhone 6.
17
Strawman Payload
•
•
•
•
•
•
•
•
•
•
•
Lyman- disk imager
Lyman- + WL inner coronagraph
WL outer coronagrah
Fluxgate magnetometer
Medium-energy ion and electron
analyzer (0.1 – 30 keV)
High-energy particle package
Low-energy ion and electron
imaging spectrometers (1 - 500
eV)
Induction magnetometers
Radio-burst instrument
Hard-X ray spectrometer
Solar irradiance measurements
• UV LBH-band imager
– Band-split for flux and average
energy determination
– Day glow suppression for true
global imaging
• Fluxgate and induction
magnetometers
• Low-energy ion and electron
imaging spectrometers (<100 eV)
• Medium-energy ion and electron
analyzer (0.1 – 10 keV)
• High-energy electron telescope
• Options
18
A MORE BALANCED KUAFU
• Simplified imaging
– Still maintain the innovation of Lyman-
coronagraphy and tracking of CMEs to 20+ solar
radii
• Enhanced in-situ measurement
– Better measurement of the solar wind on the subMHD scales will yield better characterization of
electromagnetic noises and its potential effect on
geoeffectiveness (i.e., relationship to reconnection)
19
Conclusion
An ambitious first attempt to observe
and understand the causal chain and
complexity in the Sun-Earth System,
simultaneously and continuously.
The challenge is to make it happen.
20