On the months of November 2021 天问一号飞運騎遊達达3亿CNSA – China National Space Administration – ESA – European Space agency Belt and road initiative mars mission…first Mars exploration mission, Tianwen- Martian Probe One …….祝融号Zhu Rong” , China’s “Tianwen One” in cooperation with the European Space Agency “Mars Express” mission team, launched the “Vulcan No.” rover and “Mars Express” orbiter orbit relay communications test and achieved a complete success. Before the test, the respective detectors in both directions must be instructed to make preparations for the test. At the appointed time, the “Zhurong” will send the test data to the “Mars Express”, the communication distance is about 4000 kilometers, and the communication time is 10 minutes. The “Mars Express” receives the data and forwards it to the deep space monitoring and control station of ESA. After receiving the data, the monitoring and control station sends it to the European Space Operations Center (ESOC). The ESOC is then forwarded to the Beijing Aerospace Flight Control Center. After interpretation by the Chinese technical team, Interpret the correctness of the data. The test process is shown in the figure.
Constrained by weight and size, the Mars rover has weak direct-to-ground communication capabilities and cannot meet the demand for large amounts of data transmission. Therefore, the data needs to be sent to the Mars orbiter that is closer, and the orbiter with stronger communication capability is forwarded to the ground receiving system. , This process is called relay communication.
Under normal circumstances, before establishing relay communication, the orbiter will first send an “initiate” signal to the rover, and then the rover will reply with an “confirmation” signal, and then the two parties will establish a stable two-way relay communication link, just like a friend calling The phone needs to be dialled first. Since the launch frequency of the “Mars Express” does not match the receiving frequency of the “Zhurong”, the communication link cannot be established by “dialling a phone”. The transmission frequency of “Zhurong” matches the receiving frequency of “Mars Express”. Therefore, both parties need to agree on a communication time in advance. The “Zhurong” sends data directly and “Mars Express” performs “blind reception”, which is a bit similar to the communication method of WeChat. . The “Mars Express” orbiter has a “blind harvest” function, but there has been no chance to actually use this function for more than a decade.
ESA stated that this test is a good opportunity for the “Mars Express” to verify the “blind harvest” model in orbit. According to the results of data interpretation and analysis, the mission teams of both parties confirmed that the interfaces of the relay communication equipment configured on the “Zhurong” and the “Mars Express” match conform to international standards, and the content of the transmitted data is complete and correct, and the test is a success. In the future, the two parties will further carry out scientific data relay communication cooperation on the basis of this phase of experimentation. The “Zhurong” rover currently works on the surface of Mars for 196 Mars days, has travelled 1,297 meters in total, and obtained about 10GB of raw scientific data for inspections and explorations. It has sufficient energy and is in good condition.
中欧火星探测器成功开展在轨中继通信试验
2021年11月，我国“天问一号”与欧空局“火星快车”任务团队合作，开展了“祝融号”火星车与“火星快车”轨道器在轨中继通信试验，取得圆满成功。试验前，双方向各自探测器上行指令做好试验准备。在约定时刻，由“祝融号”向“火星快车”发送测试数据，通信距离约4000千米，通信时长10分钟。“火星快车”接收数据后转发给欧空局所属深空测控站，测控站接收后发送给欧洲空间操作中心（ESOC），ESOC再转发至北京航天飞行控制中心，由中方技术团队解译后，判读数据的正确性。试验过程如图所示。
受重量和体积约束，火星车直接对地通信能力较弱，无法满足大量数据传输需求，因此需要将数据发送给距离较近的火星轨道器，由通信能力更强的轨道器转发给地面接收系统，这个过程称作中继通信。
一般情况下，在建立中继通信前，轨道器会先向火星车发送一个“发起”信号，随后火星车回复“确认”信号，然后双方建立稳定的双向中继通信链路，就像朋友打电话需先拨通电话一样。由于“火星快车”发射频率与“祝融号”接收频率不匹配，不能通过“拨通电话”的方式建立通信链路。“祝融号”发射频率与“火星快车”接收频率匹配，因此双方需要事先约定好通信时间，由“祝融号”直接发送数据，“火星快车”进行“盲收”，有点类似于微信的通信方式。“火星快车”轨道器具备“盲收”功能，但在过去十多年里一直没有机会实际使用该功能。
欧空局表示，此次试验是“火星快车”在轨验证“盲收”模式的很好机会。根据数据判读分析结果，双方任务团队确认“祝融号”和“火星快车”配置的中继通信设备接口匹配，符合国际标准，传输数据内容完整正确，试验取得成功。后续，双方将在本阶段试验的基础上，进一步开展科学数据中继通信合作。“祝融号”火星车目前在火星表面工作196个火星日，累计行驶1297米，获取巡视探测原始科学数据约10GB，能源充足、状态良好。
作者：耿言 陈刚
