The Mission Assurance Improvement Workshop (MAIW), a national space program dedicated to the development of mission success best practices, organized a team made up of engineers from leading aerospace companies including The Aerospace Corporation, to investigate the causes of CubeSat mission failure and create recommendations on how to improve mission success. Their findings were documented in a纸, "Improving Mission Success of CubeSats."
的Cubesats很受欢迎，但经常失败
Once the domain of universities which built CubeSats as a learning tool, in recent years, the wide use of CubeSats have boomed at an astonishing rate. Commercial companies, researchers, academia and the government are all building CubeSats for various operational missions. Commercial companies use these small satellites for global imaging and communications while researchers and academia continue to use CubeSats for research and development. A growing CubeSat customer is the government who is looking to use them for numerous applications such as technical demonstrations, scientific experiments, imaging, communications, and climate monitoring.
Despite the proliferation of CubeSats, one fact tends to get overlooked: CubeSats have high failure rates due to their low costs and their fast development cycle. Studies show academia success rates average only 45 percent while commercial companies have an average success rate of around 77 percent. Missions were considered successful if the CubeSat operated on orbit for 60 days or longer.
Cubesat方面的原因具有很高的任务失败率
该MAIW的CubeSat团队还负责评估用于提高任务的成功率的前景。该小组调查了一些学术，商业和政府组织从事的CubeSat的设计和开发，以确定他们的最常见的问题领域。这些领域包括通信系统，地面段和电力系统。
启动也是设计和开发问题显著原因。由于主要的有效载荷不会等待二级有效载荷，CubeSat发展者往往要压缩他们的测试方案，以满足不灵活的发布日期。相反，一些的CubeSat必须等待很长的时间发射的机会，这增加了卫星降解的机会，因为它旁边。
Mission Success Guidelines For CubeSat Developers
Based on their research, the team compiled a set of eight recommendations for CubeSat developers to improve their chances for mission success.:
- 定义范围，目标，并在一开始的成功标准。每个组织都有任务成功的定义不同，甚至在轨道上的失败可以被看作是有价值的数据或学习经验。
- 配发足够长的时间积分，验证和测试 - 优选地，三分之一的整体时间表的二分之一。检测，试验和测试更是关键的CubeSat成功。理想的情况下，测试的完整的电池将包括热真空，RF兼容性，部署硬件在半实物，和软件测试。
- 开展基于风险的任务保证,initial risk assessment to help prioritize tests and reviews. Focus on thinking through the problems that “keep you up at night,” those issues that are most critical to your mission success. Identifying these issues early on will help in planning on how to mitigate these risks.
- 设计简单性和稳健性。不要过度设计和增加不必要的复杂性在CubeSat设计。可以很容易地重新设计更简单的设计会对较少的问题。
- 包括对团队有经验的人员。与经验丰富的设计师和顾问团队一般取得更大的成功。
- Stock spare components to enable parallel development and more rigorous testing. Most CubeSats are assembled from standardized parts that are not fully protected against the space environment so designers should plan accordingly.
- Perform at least four mission assurance tests—day-in-the-life testing, communication link testing, power system testing, and thermal testing. Regular reviews, both formal and informal, help to boost success rates.
- View subsystem datasheets with skepticism. CubeSats are built with commercial parts that are sold with datasheets with information about how the part performed under ideal conditions. Space is not an ideal condition for testing, so always test the parts in an environment similar to where the CubeSat will be deployed.
Most of these broad guidelines can be tailored and implemented without much cost. Although they seem to be common sense, the study team found that few CubeSat developers followed all these recommendations. The team hopes that in the future, they can collect data from developers who actually followed all these guidelines to measure any increases in CubeSat mission success.
This article originally appeared in theMarch 2018 issue的“得到它的权利。”
