在发射前的最后一刻,SLS的首次试射被取消了。取消的原因,是在燃料泄出(注意是泄出不是泄漏)测试中技术人员发现一台发动机状态不正常,最终决定取消发射。有些媒体认为故障原因就是燃料泄漏,其实不是,至少不能说准确。NASA给出的说明中提到,这项测试叫做Bleed Test,字面意思就是燃料泄出测试。说着挺玄,其实这项测试的内容就是通过提升芯级燃料箱内的压力,让少量液氢进入发动机,对发动机进行预冷——我理解可能是让发动机系统提前适应一下温度低至零下250摄氏度的低温燃料。在测试过程中,通过检查发动机温度,一方面可以确定发动机预冷效果,另一方面也可以确认发动机与燃料箱之间的管路系统是否正常。也就是在这次测试中,SLS火箭底部4台RS-25主发动机中的一台也就是3号发动机异常,温度始终下不来,无法满足点火要求。故障原因,很可能是通往发动机的燃料管路出了问题,否则低温燃料一旦进入发动机,温度下不来不大可能。NASA表示SLS火箭目前仍然处于稳定且安全的状态,但是排故可能挺麻烦,因为火箭已经完成了推进剂的加注工作,要在这样的状态下检查发动机系统,可能确实有难度。下一个窗口是9月2号,要努力工作才可能赶得上。
#NASA每日一图# 2022-08-30 APOD:【Jupiter from the Webb Space Telescope】
This new view of Jupiter is illuminating. High-resolution infrared images of Jupiter from the new James Webb Space Telescope (Webb) reveal, for example, previously unknown differences between high-floating bright clouds -- including the Great Red Spot -- and low-lying dark clouds. Also clearly visible in the featured Webb image are Jupiter's dust ring, bright auroras at the poles, and Jupiter's moons Amalthea and Adrastea. Large volcanic moon Io's magnetic funneling of charged particles onto Jupiter is also visible in the southern aurora. Some objects are so bright that light noticeably diffracts around Webb's optics creating streaks. Webb, which orbits the Sun near the Earth, has a mirror over 6 meters across making it the largest astronomical telescope ever launched -- with 15 times more light-collecting area than Hubble.
This new view of Jupiter is illuminating. High-resolution infrared images of Jupiter from the new James Webb Space Telescope (Webb) reveal, for example, previously unknown differences between high-floating bright clouds -- including the Great Red Spot -- and low-lying dark clouds. Also clearly visible in the featured Webb image are Jupiter's dust ring, bright auroras at the poles, and Jupiter's moons Amalthea and Adrastea. Large volcanic moon Io's magnetic funneling of charged particles onto Jupiter is also visible in the southern aurora. Some objects are so bright that light noticeably diffracts around Webb's optics creating streaks. Webb, which orbits the Sun near the Earth, has a mirror over 6 meters across making it the largest astronomical telescope ever launched -- with 15 times more light-collecting area than Hubble.
#adaptation#
NASA had the launch of Artemis I moon mission scrubbed due to engine concerns at the eleventh hour. The project is the culmination of years of efforts to establish a sustained presence on the Moon, 50-plus years after the last Apollo astronauts ventured to the lunar surface. The agency is eyeing a normal liftoff of September 2nd.
1. have sth done
2. due to
3. enegine issues/concerns/problems
4. at the eleventh hour
5. sth be the culmination of ... years of ...
6. a sustained presence
7. venture to
8. eye
NASA had the launch of Artemis I moon mission scrubbed due to engine concerns at the eleventh hour. The project is the culmination of years of efforts to establish a sustained presence on the Moon, 50-plus years after the last Apollo astronauts ventured to the lunar surface. The agency is eyeing a normal liftoff of September 2nd.
1. have sth done
2. due to
3. enegine issues/concerns/problems
4. at the eleventh hour
5. sth be the culmination of ... years of ...
6. a sustained presence
7. venture to
8. eye
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