为什么SpaceX的星链计划卫星只有一个太阳能板阵列?Why do the SpaceX Starlink satellites only have one solar array?

【翻译自quora,原作者 Jeffrey Naujok 】

Thanks for the ATA.

Officially, the reason is because it reduces potential sources of failure. I think that’s part of the truth.

官方的说法是这减少了潜在的故障。我认为这是原因的一部分。

The problem with thinking of Starlink like other satellites is that it’s a completely new paradigm in satellite technology.

与其他卫星不同的是,Starlink是一种全新的卫星技术规范。

Prior to Starlink, satellites were “one-off” technology. You sent a satellite to orbit one time, and you expected it to be up there for 20 years. And it had to work, because the satellite cost half a billion dollars to build. So you loaded it with redundant systems, because adding $10M of backups is still cheaper than losing the satellite.

在Starlink之前,卫星是“一次发射,多次维修”的东西。 您只将卫星发送到轨道一次,并且希望它在那里停留20年。 它必须工作,因为人造卫星的制造成本为10亿美元。 因此,您要为它添加冗余系统,因为添加1000万美元的备份仍然比丢失卫星便宜。

(The GOES-3 satellite operated for 38 years before being sent decommissioning commands in 2016.)

(GOES-3卫星运行了38年,于2016年被收到退役指令。)

But Starlink doesn’t work that way. They’re going to launch 12,000 satellites. That means each satellite is going to have to be comparatively cheap to produce. And, they’re going to lose satellites. A lot of them. And they are only planned to be in orbit for 5 years. That means they will need to be constantly replacing them.

但是Starlink不能那样工作。 他们将发射12,000颗卫星。 这意味着每颗卫星的生产成本将相对较低。 而且,他们将不断失去这些卫星。 而且这些卫星仅计划在轨道上运行5年。 这意味着它们将需要不断替换它们。

So they not only need to be cheap, they need to be really cheap. Elon already stated that the satellites cost more to launch than they cost to build.

因此,它们不仅需要便宜,而且还必须真正便宜。 Elon已经说过,发射卫星的成本要高于制造成本。

That’s pretty much unprecedented in the history of modern space flight.

这在现代太空飞行的历史上几乎是前所未有的。

If a launch costs about $40M on a reused booster, that means each satellite costs only about $650,000 or less.

如果使用重复使用的助推器,一次发射成本约为4000万美元,这意味着每颗卫星的成本仅为650,000美元或更低。

Okay, look, I know that’s a lot of money to you or me, but in terms of satellites up until this point, it’s peanuts.

好吧,看,我知道这对您或我来说都是很多钱,但是就目前为止的卫星而言,这都不算钱。

And that means it may be cheaper to replace these satellites than to deal with putting redundant systems on it. Especially when you take all the extras into account.

这意味着更换这些卫星,可能比为这些卫星添加备份系统更便宜。 特别是当您考虑所有额外功能时。

  • Redundant arrays take up more space. More space means fewer satellites per launch. If the launch cost is already more than the satellite, then that’s a direct multiplier to the bottom line.
  • 冗余阵列需要占用更多空间。 更多的空间意味着每次发射的人造卫星数量更少。 如果发射成本已经超过卫星建造的成本,那么这就是底线的直接乘数。
  • Two arrays means more mass in orbit, out on long lever arms, which means the krypton thrusters have to work harder to get them to turn. Which wastes fuel, which shortens the life of the satellite.
  • 两个阵列意味卫星在轨道上的质量更大,两个阵列需要安放在更长的杠杆臂上,这意味着推进器必须更努力地工作才能使其转动。 这浪费了燃料,从而缩短了卫星的寿命。
  • The solar arrays are heavy. More weight means fewer satellites to launch, and also, ironically, a longer de-orbit time.
  • 太阳能电池板很重。 更大的重量意味每次只能发射更少数量的卫星,而且具有讽刺意味的是,更长的离轨时间。
  • Large flat panels also means more atmospheric drag. That means shorter life in orbit.
  • 大平板也意味着更大的大气阻力。 这意味着在轨寿命缩短。
  • Deploying one panel means one set of sun-tracking motors, one set of electrical connections, one set of circuit breakers, one set of wires, etc, etc. It really is simpler.
  • 部署一组太阳能面板意味着只需要一组太阳跟踪马达,一组连接电缆,一组断路器,一组电线等。这要比两组简单。
  • Simpler means easier and cheaper to mass produce, that means less expensive, and faster to build. They need to make 12,000 of these things. Anything that makes it faster, and cheaper to build is good.
  • 更简单意味着批量生产更容易,更便宜,制造更快。 他们需要制造12,000件东西。 任何使它更快,更便宜的构建都是好的。

We need to stop thinking of these things like prized heirlooms, and more like cheap knick-knacks made in China. Sort of a “disposable-satellite” way of thinking.

我们不应该再局限在传统的思维里,而应该把这些卫星当成中国制造的价格低廉的“小玩意”那样。有点“一次性卫星”的意味。

Dang, we’re living in the future.

Leave a Reply