用木材造卫星?
Earth-orbiting satellites usually end their lives in a fiery reentry — but a tiny CubeSat scheduled for launch by the European Space Agency later this year might put off a warmer glow than most in its final moments.
地球轨道卫星通常会在重返大气层时燃烧而结束生命,但欧洲航天局计划于今年晚些时候发射的一颗微型立方体卫星可能会在其最后时刻释放出比大多数卫星更温暖的光芒 。
That's because WISA-Woodsat is made mostly out of plywood.
这是因为这颗名为WISA-WOODSAT的卫星是由木质胶合板做的。
It's not such a crazy idea:
这并非什么疯狂的想法:
Since it became widely available about a century ago, plywood has been prized for its strength, rigidity and durability — three things that are good in a spacecraft.
自从大约一个世纪前胶合板广泛使用以来,它一直因其强度、刚性和耐久性而备受赞誉——这三种特质在航天器中都是需要的 。
Woodsat is designed to test how well WISA plywood — a special high-quality variety produced by UPM Plywood in Finland, one of the project's sponsors — can withstand the rigors of space.
Woodsat的设计目的是测试WISA胶合板(WISA胶合板是该项目的赞助商之一芬兰UPM胶合板公司生产的一种特殊的高品质胶合板)在严酷的太空环境下的耐受度。
WISA Woodsat is the brainchild of Jari Mäkinen, a writer and broadcaster from Finland who co-founded a company called Arctic Astronautics, which markets fully functional replicas of orbit-ready CubeSats.
WISA Woodsat是芬兰作家兼广播员杰瑞·麦吉能的创意,他是一家名为北极宇航公司的联合创始人,该公司销售的是可进入轨道的立方体卫星的全功能复制品。
"I've always enjoyed making model planes, involving a lot of wooden parts. ... [This] got me wondering; why don't we fly any wooden materials in space?" he said in an ESA news release.
“我一直很喜欢制作飞机模型,其中涉及到很多木制部件. ... [这]让我好奇; 为什么我们不让木质材料进入太空呢?”他在欧洲航天局的新闻发布会上说道。
Believe it or not, plywood for small satellites "could be a great low-cost alternative to traditional materials and is absolutely feasible with the right testing and modifications," Michelle Johnson, an associate fellow in materials and process engineering at Lockheed Martin Space, tells us.
“信不信由你,用于小型卫星的胶合板“可能是传统材料的一种极好的低成本替代品,通过正确的测试和修改是绝对可行的,”洛克希德·马丁航天公司材料和过程工程的副研究员米歇尔·约翰逊告诉我们。
Modern spacecraft are often made out of carbon fiber composites "which is essentially an engineered improvement on nature's original composite, i.e. wood," she explains.
她解释说,现代航天器通常由碳纤维复合材料制成,“这基本上是对自然原始复合材料(即木材)的工程上的一种改进。 ”
Sarbajit Banerjee, a chemistry professor at Texas A&M University, agrees that wood in space isn't an entirely crazy idea.
德州农工大学的化学教授塞巴吉特·班纳吉也认为,在太空中使用木材并不完全是一个疯狂的想法 。
"Wood is an amazing structural material — it does very well in comparison to other materials in terms of strength-to-weight ratios," he tells us.
“木材是一种神奇的结构材料——与其他材料相比,它的强度重量比非常好,”他告诉我们。
"However, there are several challenges to the use of wood in high-performance applications such as spaceflight," he concedes.
他承认:“然而,在航天等高性能应用中使用木材还存在一些挑战。”
Because of the grain and the way trees grow, wood can be weaker in some dimensions than others, Banerjee notes, although plywood is specifically designed to minimize that. It's also difficult to shape without losing strength and it doesn't easily dissipate energy from impacts.
班纳吉指出,由于树木的纹理和生长方式,木材在某些方面可能比其他方面更脆弱,尽管胶合板是专门设计来减少这一点的,它也很难在不失去强度的情况下塑形,而且它也不能轻易地消散冲击力带来的能量 。
And then there's the space environment itself. Satellites in orbit "inevitably suffer radiation damage — which in the case of wood can considerably degrade mechanical strength," he says.
然后是太空环境本身。 他说,卫星在轨道上“不可避免地遭受辐射损伤——就木材而言,辐射损伤会大大降低机械强度。
Samuli Nyman, the project's chief engineer and also a co-founder of Arctic Astronautics, says, "The base material for plywood is birch, and we're using basically just the same as you'd find in a hardware store or to make furniture."
该项目的总工程师、北极宇航公司的联合创始人萨穆利·尼曼说:“胶合板的基本材料是桦木,我们使用的材料基本上和你在五金店或做家具用的材料一样。”
"The main difference is that ordinary plywood is too humid for space uses, so we place our wood in a thermal vacuum chamber to dry it out," he says in the ESA news release.
他在欧洲航天局的新闻发布会上说:“主要的区别是普通胶合板对在太空中使用来说太潮湿了,所以我们把木材放在热真空室中干燥。”
Nyman says the Woodsat team will also be testing varnishes and lacquers aboard the spacecraft.
尼曼说,伍德塞特团队还将测试飞船上的清漆和漆器。
问题
文中提到的木质卫星的创意最初是由哪个国家的人想出来的?