Plan-A Comments…on Jupiter Option
Presented Yesterday.
J. Kawaguchi

1Scenario A_Ballsitic-2:
Actual Flight Sequence for 39deg, 1AU
DEPARTURE DATE = 2015 11 16 12
6-ELM(O+W)=
0.522430d+09 0.716807d+00 0.412549d+01
0.538077d+02 0.538723d+02 0.000000d+00
AND EPOCH=2015 11 16 13 10 46• 30deg, 5.5 (1.5) AU in 2years,

1 13 15 2017 12 16 12 0 0 0 9.467
6-ELM(O+W)=
0.480394d+09 0.691216d+00 0.303261d+02
0.394643d+02 0.350523d+02 0.000000d+00
AND EPOCH=2020 10 29 14 7 25 SW Alt.= 3208524 km• 35 deg, 2.2 (1.4) AU in 5years,

2 15 13 2020 11 1 10 17 52 0 7.261
6-ELM(O+W)=
0.237473d+09 0.375005d+00 0.347301d+02
0.394643d+02 0.421404d+02 0.358872d+03
AND EPOCH=2020 11 1 10 17 52 SW Alt.= 546 km• 39deg, 1.0 (1.0) AU in 7years,

3 13 13 2022 11 1 7 53 52 0 20.007
6-ELM(O+W)=
0.149599d+09 0.166995d-01 0.389541d+02
0.388792d+02 0.103333d+03 0.297263d+03
2022 11 1 7 53 52
4 Final ORBIT.

With NO scheduled Delta-V.
Sci Obs possible all the time.
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Scenario A_Ballsitic-2:
Distance to Sun and Earth for 39deg, 1AU

Willcontinue
maintaining
1AUdistance.
3Strategy A-Ballistic-2

4Strategy A-Ballistic-2+
5 or more swingbys lowers the perihelion
distance down below 0.3 AU.

5

Mass Breakdown (with Options)

P/L Ratio

0.32

0.06

0.11

0.37 <- 10% Planetary s/c

This another concept may be launched via H-IIB with 4S fairing.

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Why negative via Solar Sail ? (1)• JAXA is very much keen on Solar Sail. But it is on Solar
Power Sail that is a Hybrid Propulsion.
• Pure sail propulsion is perfect, if cruise period is enoughlong.
• For instance, if 50% mass can be poured for propulsion,high Isp electric propulsion replaces Sail Membrane +Mechanism.
• Solar Power Sail generates Power driving Ultra High Isp
Electric Propulsion. It has better benefit. So, JAXA is for
Solar Power Sail instead of Pure Sail.

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Why negative via Solar Sail ? (2)• Pure Photon Sail is effective in Smaller Spacecraft owing toLower Ballistic Coefficient.
• About the Application to larger spacecraft, it is lessadvantageous over either of Electric Propulsion or Hybrid
Solar Power Sail Propulsion. Besides, High resolution
Telescopic observation does not fit for the spacecraft thatalways changes its attitude.
• Still deploying 20k square meters sail is a key. JAXA’s
hybrid propulsion concept reduces sail area drasticallydown to 2k square meters for 600kg spacecraft and makes
the credibility more high.

84S Fairing Compatibility

Even with a HGA and enlarged Solar Array Panels, itfits for 4S fairing of H-IIA.
9Spatial Resolution Index• For Polar Region Observation:dsε	Resolution Index at 1 AU, if normally faces, corresponds to 6x10-9.
When 1000x1000 pixels for 0.5degx0.5deg FOV, e=10-5 radian, and it
results in 1,500 km/pixel resolution.

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Parameters …..(1)• There are three major parameters that affect the mission
scenario.
1. Resolution (Index) to be as high as possible.

2. Heat Flux to be below Specification.

3. Observation Period in High Latitude. In other words,
angular velocity to be below a threshold.

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Parameters …..(2)Constraint on both Heat Flux and Observation Period iscommon, and they restrict simply the distance to theSun.
Enhancing Resolution (Index) apparently seen by both
reducing the distance to the Sun and making inclination
higher.
However, this may not be true in view of Heat Flux andObservation points of views.
So, we should be modest as to the distance to the Sun, andhave to try to make the inclination higher.
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Solar Orbiter Mission Phase

0.25AU, 24 deg in 6 years in Solar Orbiter Scenario.
0.6AU when 26 degrees = 4.9x 10-9 as Resolution Index.
0.35AU when -25 degrees = 8x 10-9 as Resolution Index.

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A_Ballistic-1
Well maintains highinclination.

Resolution Indexreaches 6x10-9 (1/km)

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A_Ballistic-2+
Well maintains highinclination.

Resolution Indexreaches 12x10-9 (1/km)
This is owing
to shortened
distance toSun.
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Communication Sys on Solar Probe+
The Ka-band (32-GHz) high-power transmitters are 40-W RF output power
traveling wave tube amplifiers (TWTAs). The TWTAs are ~50% efficient (DCpower of 80 W) and build on heritage from TWTAs on the Kepler (35 W at32 GHz) and LRO (40 W at 26 GHz) missions. The Xband transmitters are
13-W TWTAs that are heritage from the New Horizons mission and are~40% efficient (32 W of primary DC power).
The two RF transponders are based on the advanced digital receiver flown on
the New Horizons mission and on digital and Ka-band hardware developedfor NASA on the CoNNeCT program. The transponders each require only 4
W of primary power in receive-only mode, 8.7 W in receive/X-band transmitmode, 9.7 W in receive/Ka-band transmit mode, or 14.1 W in receive/X- andKa-band transmit mode.
The output from either of the X-band TWTAs may be steered to any of theantennas through a network of single-pole-double-throw (SPDT) andtransfer (XFER) switches, which are themselves configured for redundant
operation.
Similarly, the Ka-band TWTAs are switched to the HGA. Hybrid couplers areused with each of the X-band and Ka-band TWTA pairs to increase
downlink system reliability.
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Communication System Assumes Similar
Configuration to Solar Probe+

Simply due to X toKa s/c and groundantenna gain
differences.
We, JAXA
needs bigefforts toHayabusa & PLANETC of JAXA:
improve theWith 20W X-down, with 1.6m HGA and 64m UDSC antenna: 8kbps at 2AU
at maximum.
capability.
This is converted to:17
With 40W, with 0.8 HGA and 34m USC/JAXA antenna: approximately 1kbps at 2AU,
1.2kbps at 1.8AU. JAXA current communication level is 4 times worse than Solar Probe+.

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