Fig.1

Mars north pole ice cap （photographed by Tianwen-1）［15］

Fig.2

Mars south pole ice cap （photographed by Mars Express）［16］

Fig.3

Structural model of Europa［19］

Fig.4

Phenomenon of water-ice jets on surface of Enceladus （photographed by Cassini spacecraft）［24］

Fig.5

Photo of Triton （photographed by Voyager 2）［25］

Fig.6

CHINARE/JARE type deep ice core drill［34］

Fig.7

Working principle of the hot water drill［33］

Fig.8

Working principle of the coiled tubing drill［36］

Fig.9

Working principle of the closed-cycle water-heated ice-melter［37］

Fig.10

“Philberth”probe［39］

Fig.11

Schematic diagrams of two configurations of the pendulum-stabilized ice-melting detector［41］

Fig.12

Schematic diagram of the pendulum-stabilized detector manufactured by CRREL［42］

Fig.13

Schematic diagram of structure of RECAS［44］

Fig.14

Schematic diagram and working principle of water-absorbing and pressure-applying ice-melting probe［46］

Table 1

Parameters of electrically heated ice-melting detector applied on Earth

Table 2

Comparison of advantages and disadvantages of different ice-penetrating detectors［36］

Fig.15

Conceptual image of Cryobot mission［52］

Fig.16

Schematic diagram of CHIRPS［54］

Fig.17

Schematic diagram of Cryobot for Mars exploration［53］

Fig.18

Structure of lander integrated with a reactor［55］

Fig.19

Schematic diagram of structure of reactor system on the lander［55］

Fig.20

Concept of an ice-melting detector integrated with a reactor［56］

Fig.21

Working principle of SIPR detector［60］

Table 3

Comparison of parameters of two types of Tunnelbots

Fig.22

Structure of reactor Tunnelbot［61］

Fig.23

Structure of GPHS Tunnelbot［61］

Fig.24

Schematic diagram of repeater［61］

Fig.25

Schematic diagram of VALKYRIE［67］

Fig.26

Schematic diagram of DLP for sub-ice penetration missions in ice layers of 10~100 m［68］

Fig.27

Schematic diagram of PROMETHEUS［70］

Fig.28

Schematic diagram of THOR ［72］

Fig.29

Schematic diagram of Europa SLUSH［73］

Fig.30

Pulsed-power peristaltic melt probe［74］

Fig.31

Schematic diagram of the overall structure［75］

Fig.32

Graphic depiction of SWIM-sensing with independent micro-swimmers［76］

Fig.33

Schematic diagram of EnEx-IceMole structure［79］

Fig.34

Schematic diagram of Teredo IceShuttle structure［80］

Fig.35

Leng-AUV［81］

Fig.36

Schematic diagram of TRIPLE-IceCraft structure［82］

Fig.37

Schematic diagram of TRIPLE-IceCraft launching the nanoAUV［84］

Fig.38

Schematic diagram of ice-melting test device［86］

Table 4

Experimental results of four groups of experiments

Fig.39

Thermal drill prototype and its internal components［93］

Fig.40

Concept of an ice-penetrating probe capable of deploying an AUV［96］

Fig.41

Deployment process of the ice penetrator proposed by ESA/NASA［102］

Fig.42

Attenuation of RF signals during transmission through ice（-15 ℃）［54］