Deployment Demonstration of Supersized Membrane for Spinning Solar Sail
Osamu Mori, Hirotaka Sawada, Yuichi Tsuda, Ryu Funase and
Jun’ichiro Kawaguchi (ISAS/JAXA),
Fuminori Hanaoka, Michihiro Matsumoto, Shunsuke Okada, Yusuke Shibasaki,
Yoji Shirasawa, Akifumi Kitajima, Masatoshi Hirabayashi, Yuichi Miwa and
Simanjuntak Triwant (Univ. of Tokyo),
Masataka Arakawa (Tokyo Denki Univ.) and Masayuki Sugita (Aoyama Gakuin Univ.)
Abstract
JAXA is studying solar power sail as a new propulsion engine for deep space explorations. In this paper,
the sail shape and equipment layout for small-sized solar power sail mission are proposed. The deployment
method, sequence and mechanism are also introduced. The deployment motions are analyzed by numerical
simulations using multi-particle models in order to verify the deployment.
超大型ソーラーセイル膜面展開実証
森 治，澤田 弘崇，津田 雄一，船瀬 龍，川口 淳一郎（ISAS/JAXA），
花岡史紀，松本道弘，岡田俊輔，芝崎裕介，白澤洋次，
北島 明文，平林 正稔，三和 裕一，トリワント（東大・院），
荒川将孝（東電大・院），杉田昌行（青学大・学）
摘要
JAXA では，深宇宙探査のための新しい推進機関として，ソーラー電力セイルを検討している．
本論文では，小型ソーラー電力セイル実証機の膜面形状・配置，展開方式・手順・機構を提案す
る．また，多粒子モデルを用いた数値シミュレーションにより展開挙動を明らかにし，展開の実
現性を示す．
1. Introduction
Solar sail is a propulsion engine using no fuel
because it can receive photon momentum. Japan
Exploration Agency (JAXA) proposes solar power sail
as a new propulsion engine for deep space explorations.
It can be a hybrid engine, if the ion-propulsion engines,
whose specific impulse is very high, are driven by the
solar cells on the membrane.
JAXA is studying two missions to demonstrate solar
power sail as shown in Fig. 1. Small-sized solar power
sail in the early 2010s is the front-loading measures for
risk reduction. The minimum success criteria are the
deployment of the sail whose diameter is 20m and
electric power supply using the solar cells on the
membrane. The full success criteria are the acceleration
and navigation using photon sail for the first time. On
the other hand, the medium-sized solar power sail in the
mid-2010s integrates ion-propulsion engines with solar
power sail of diameter 50m. The destinations of the
spacecraft are the Jupiter and the Trojan asteroids.
Some kinds of deployment methods have been
investigated[1],[2]. JAXA is studying the spinning type,
in which the membrane is deployed and maintained flat
by the centrifugal force. This method is expected to be
realized with simpler and lighter-weight mechanism
than other ways, because it does not require rigid
structural elements. The authors have been
demonstrating it. The dynamic deployment of φ10m sail
was performed successfully using an S-310 sounding
rocket at 08/2004 [3]. The static deployment of φ20m
sail was demonstrated using a high altitude balloon at
08/2006 [4].
In this paper, the sail shape and equipment layout for
small-sized solar power sail mission are proposed. The
deployment method, sequence and mechanism are also
introduced. The deployment motions are analyzed by
numerical simulations using multi-particle models in
order to verify the deployment.
Small-sized solar power sail
In the early 2010s
φ20m
Medium-sized solar power sail
In the mid-2010s
φ50m
Fig. 1 Solar power sail missions
2. Proposals for small-sized solar power sail
2.1 Sail
The sail shape and equipment layout is proposed as
shown in Fig. 2.
Membrane: The shape of the membrane is a square
whose diagonal is 20m. It consists of four trapezoid
petals. The direction of folded lines is normal to that of
centrifugal force. It is made of polyimide whose
thickness is 7.5 μm. It is simple and easy to product
relatively.
Tether: The membrane should not be contact on the
main body after the deployment. They are connected by
tethers.
Tip mass: Four masses are attached on the four tips of
the membrane. It adjusts the centrifugal force and the
inertial momentum of the membrane.
Solar cell: Solar cells are attached on the membrane
partly. The area ratio is 10%.
Steering device: Eight variable reflectance elements are
loaded near the tips of the membrane. The control of the
spin direction and rate can be performed using them as
shown in Fig. 3[5].
Steering device
Tip mass
Trapezoid petal
Solar cell
Tether
Main body
Fig. 2 Sail shape and equipment layout
OFF ON
ON OFF
ON
ON
ON
OFF
OFF
OFF
Tip mass
Down
Up
Control of spin rate Control of spin direction
Down
Down Down
Up
Up Up
Fig. 3 Steering device
2.2 Deployment
The deployment method of the sail is proposed as
shown in Fig. 4. It consists of two stages. In folded
configuration, each petal is line-shaped and rolled up
around the satellite as shown in (1). In the first stage,
the rolling petals are extracted like a Yo-Yo despinner,
and form a cross shape. The shape is maintained by
stoppers as shown in (3). In the second stage, the
stopper is released and each petal is developed to form a
square shape. If the first stage deployment is performed
dynamically, each petal should be twisted around the
main body just after the deployment. Therefore it needs
to be deployed statically at the first stage. On the other
hand, it is supposed to be deployed dynamically at the
second stage.
This paper introduces two types of deployment
mechanism. Fig. 5 shows a continuous deployment
mechanism. The Yo-Yo despinner is restricted by a
stopper. Each stopper rotates relative to the main body
slowly to deploy each petal continuously at the first
stage. The second stage deployment is started by
releasing four stoppers after the first stage deployment.
Fig. 6 shows a divided deployment mechanism. Each
petal is held by several stoppers, which are aligned
properly. It was deployed step by step at the first stage
by releasing stoppers 1-5 in number order. It was
deployed dynamically at the second stage by releasing
stopper 6. This mechanism is simple relatively. The
deployment motion at the first stage is, however,
complicated.
The deployment sequence is defined as follows.
1) Separation from rocket with slow spin (2rpm)
2) Release of launch lock
3) Spin up using RCS (2rpm -> 36rpm)
4) First stage deployment (36rpm -> 14rpm)
5) Second stage deployment (14rpm -> 5rpm)
6) Spin down using RCS (5rpm -> 2rpm)
7) Control of spin direction and rate using steering
devices
The spin rate is decreased at the first and second stages,
because the inertial momentum of the sail is increased.
Fig. 4 Deployment method
Relative
Rotation
(Motor2)
Main body
Stopper
(1) First stage (2) Stopper release (3) Second stage
Fig. 5 Continuous deployment mechanism
Stoppers are released
in number order.
6
5
4
3
2
1
First stage
Second stage
Sail
Tether Cutter
Stopper
Hinge
(1) Folded sail (2) Stopper release
Fig. 6 Divided deployment mechanism
3. Deployment motion analysis by numerical
simulations
3.1 Modelling
Analytical models of the first and second stage
deployments are shown in Fig. 7. The parameters of the
main body and the sail are set as follows.
<Main body> rigid cylinder model
Weight: 300kg
Inertial moment:
{ } { }[ ] 2 kgm 1 . 0 , 8 . 0 , 0 . 1 , 9 . 80 , 7 . 46 , 6 . 53 , , , , , ? = zx yz xy zz yy xx I I I I I I
Diameter: 1.2m
<Sail> multi-particle model
Weight: 9.9kg
(including four tip masses whose weight is 0.5kg*4)
Inside diagonal: 4.5m
Outside diagonal: 20m
Young’s modulus: 3.2GPa
(a) First stage (b) Second stage
Fig. 7 Analytical model
3.2 Results of numerical simulations
Considering the deployment sequence, the nominal
conditions of numerical simulation for the first and
second stages are set as follows.
<First stage>
Initial spin rate: 36rpm
Initial nutation angle: 5deg
Height offset: 20mm
Deployment unbalance: none
Sail damping: none
Deployment method: continuous deployment (120sec)
<Second stage>
Initial spin rate: 14rpm
Initial nutation angle: 5deg
Height offset: 20mm
Deployment unbalance: none
Sail damping: none
Deployment method: dynamic deployment
The height offset is defined as the distance between the
center of the membrane and the center of the main body.
Fig. 8 shows the pictures of deployment motion at
the first and second stages.
These conditions are changed as follows. The graphs of
spin rate, attitude angle and tip angles (in-plane and outof-
plane) of the first and second stages are shown in
Figs. 9 and 10. Tip angles (in-plan and out-of-plane) are
defined as shown in Fig. 11.
<First stage deployment>
(a) In the case of nominal condition.
The spin rate is decreased because the inertial
momentum of the sail is increased during the continuous
deployment (0-120sec), and it becomes constant after
the deployment. The attitude angle and tip angles (inplane
and out-of-plane) are oscillating. They are not
converged because the sail damping is not considered.
The tip angle (in-plane) is increased just after the
continuous deployment (120sec). It is, however, not
more than 20deg. Then each stopper does not collide
with each petal if it was released.
(b) In the case that initial nutation angle is set 0deg.
The oscillation amplitudes of the attitude angle and tip
angles (in-plane and out-of-plane) are decreased in
comparison with the results of the nominal case. On the
other hand, they are changed little if the height offset is
set 0mm.
(c) In the case that the deployment of one petal is
delayed for 3 seconds.
Red solid lines and blue broken lines in the graphs of tip
angles show the results of delayed petal and the other
petal respectively. The differences of these results are
little. The spin rate and attitude angles are nearly equal
to those in the nominal case.
(d) In the case that the deployment is divided into 5 and
that stoppers are released every 800 seconds.
The spin rate, attitude angle and tip angles (in-plane and
out-of-plane) are oscillating drastically just after every
stopper is released. There is a possibility that the petals
collide with each other, since the maximum amplitude
of the tip angle (in-plane) is 120deg. The oscillation
amplitudes can be decreased if the division number is
increased or dampers are included. The deployment
mechanism becomes, however, complicated.
These results show that continuous deployment at the
first stage is feasible considering the initial nutation, the
height offset and the deployment unbalance. On the
other hand, the feasibility of divided deployment is
dependent on the division number and dampers.
<Second stage deployment>
(a) In the case of nominal condition.
The sail is expanded dynamically in a few seconds. The
spin rate, attitude angle and tip angles (in-plane and outof-
plane) are changed dramatically just after the
deployment start. Using tethers, the sail does not collide
with the main body and the oscillation amplitudes of
them are decreased with time.
(b) In the case that initial nutation angle is set 0deg.
The oscillation amplitudes of the attitude angle and tip
angle (out-of-plane) are decreased in comparison with
the results of the nominal case just after the deployment
start. On the other hand, they are changed little if the
height offset is set 0mm.
(c) In the case that the deployment of one petal is
delayed for 3 seconds.
Red solid lines and blue broken lines in the graphs of tip
angles show the results of delayed petal and the other
petal respectively. Although the attitude angle and tip
angle (out-of-plane) is increased due to the deployment
unbalance, the deployment is feasible.
(d) In the case that the connection method using tethers
are changed as shown in Fig. 12.
The spin rate and tip angle (in-plane) can be converged
quickly despite no sail damping.
These results show that dynamic deployment at the
second stage is feasible considering the initial nutation,
the height offset and the deployment unbalance. The
spin rate, attitude angle, tip angles (in-plane and out-ofplane)
can be converged quickly by adjusting the
connection method using tethers.
(a) First stage deployment
(b) Second stage deployment
Fig. 8 Pictures of deployment motion
0 100 200 -4
-3
-2
-1
0
time [s]
spin rate [rad/s]
0 100 200 0
2
4
6
8
10
time [s]
attitude angle [deg]
0 100 200 -30
-20
-10
0
10
20
30
time [s]
tip angle (in-plane) [deg]
0 100 200 -10
0
10
time [s]
tip angle (out-of-plane) [deg]
Spin rate [rad/s] Attitude angle [rad]
Tip angle (in-plane) [deg] Tip angle (out-of-plane) [deg]
(a) Nominal
Spin rate [rad/s] Attitude angle [rad]
Tip angle (in-plane) [deg] Tip angle (out-of-plane) [deg]
0 100 200 -4
-3
-2
-1
0
time [s]
spin rate [rad/s]
0 100 200 0
2
4
6
8
10
time [s]
attitude angle [deg]
0 100 200 -30
-20
-10
0
10
20
30
time [s]
tip angle (in-plane) [deg]
0 100 200 -10
0
10
time [s]
tip angle (out-of-plane) [deg]
(b) No initial nutation
Spin rate [rad/s] Attitude angle [rad]
Tip angle (in-plane) [deg] Tip angle (out-of-plane) [deg]
0 100 200 -4
-3
-2
-1
0
time [s]
spin rate [rad/s]
0 100 200 0
2
4
6
8
10
time [s]
attitude angle [deg]
0 100 200 -10
0
10
time [s]
tip angle (out-of-plane) [deg]
0 100 200 -30
-20
-10
0
10
20
30
time [s]
tip angle (in-plane) [deg]
(c) Deployment unbalance
Spin rate [rad/s] Attitude angle [rad]
Tip angle (in-plane) [deg] Tip angle (out-of-plane) [deg]
0 1000 2000 3000 4000 5000 -4
-3
-2
-1
0
time [s]
spin rate [rad/s]
0 1000 2000 3000 4000 5000 0
2
4
6
8
10
time [s]
attitude angle [deg]
0 1000 2000 3000 4000 5000 -120
-60
0
60
120
time [s]
tip angle (in-plane) [deg]
0 1000 2000 3000 4000 5000
-10
0
10
20
30
time [s]
tip angle (out-of-plane) [deg]
(d) Divided deployment
Fig. 9 Results of first stage deployment
0 1000 2000 3000 -1.5
-1
-0.5
0
time [s]
spin rate [rad/s]
0 1000 2000 3000 0
10
20
30
time [s]
attitude angle [deg]
0 1000 2000 3000 -180
-120
-60
0
60
120
180
time [s]
tip angle (in-plane) [deg]
0 1000 2000 3000 -30
-20
-10
0
10
20
30
time [s]
tip angle (out-of-plane) [deg]
(a) Nominal
Spin rate [rad/s] Attitude angle [rad]
Tip angle (in-plane) [deg] Tip angle (out-of-plane) [deg]
0 1000 2000 3000 -1.5
-1
-0.5
0
time [s]
spin rate [rad/s]
0 1000 2000 3000 0
10
20
30
time [s]
attitude angle [deg]
0 1000 2000 3000 -180
-120
-60
0
60
120
180
time [s]
tip angle (in-plane) [deg]
0 1000 2000 3000 -30
-20
-10
0
10
20
30
time [s]
tip angle (out-of-plane) [deg]
(b) No initial nutation
0 1000 2000 3000 -1.5
-1
-0.5
0
time [s]
spin rate [rad/s]
0 1000 2000 3000 0
10
20
30
time [s]
attitude angle [deg]
0 1000 2000 3000 -180
-120
-60
0
60
120
180
time [s]
tip angle (in-plane) [deg]
0 1000 2000 3000 -30
-20
-10
0
10
20
30
time [s]
tip angle (out-of-plane) [deg]
(c) Deployment unbalance
0 1000 2000 3000 -1.5
-1
-0.5
0
time [s]
spin rate [rad/s]
0 1000 2000 3000 0
10
20
30
time [s]
attitude angle [deg]
0 1000 2000 3000 -30
-20
-10
0
10
20
30
time [s]
tip angle (out-of-plane) [deg]
0 1000 2000 3000 -180
-120
-60
0
60
120
180
time [s]
tip angle (in-plane) [deg]
(d) Tether
Fig. 10 Results of second stage deployment
Fig. 11 Definition of tip angles
Fig. 12 Connection method using tethers
4. Conclusions
The square-shaped sail and its equipment layout
were proposed for small-sized solar power sail mission.
The two-stage deployment was also proposed. The
mechanisms of continuous deployment and divided
deployment were introduced. Numerical simulations
using multi-particle models showed that continuous
deployment at the first stage and dynamic deployment at
the second stage were feasible.
References
[1] G. Greschik and M. M. Mikulas, “Design Study of a
Square Solar Sail Architecture,” J. of Spacecraft and
Rockets, Vol.39, No.5, 653-661, 2002.
[2] J. D. Hinkle, P. Warren and L. D. Peterson,
“Geometric Imperfection Effects in an Elastically
Deployable Isogrid Column,” J. of Spacecraft and
Rockets, Vol.39, No.5, 662-668, 2002.
[3] Y. Tsuda, O. Mori, S. Takeuchi and J. Kawaguchi, “Flight
Result and Analysis of Solar Sail Deployment Experiment using
S-310 Sounding Rocket,” Space Technol., Vol. 26, Nos.
1-2, pp. 33-39, 2006.
[4] S. Nishimaki, O. Mori, M. Shida and J. Kawaguchi,
“Stability and Control Response of Spinning Solar Sailcraft
containing A Huge Membrane,” 57th International
Astronautical Congress, IAC-06-C1.1.07, Valencia, Oct.
2-6, 2006.
[5] F. Hanaoka, O. Mori, R. Funase, Y. Tsuda and J.
Kawaguchi, “On the Feasibility of Navigation Control
of Solar Sail Spacecraft,” 17th Workshop on
Astrodynamics and Flight Mechanics, 2007.