海军的先锋卫星发射器；

the Navy's Vanguard satellite launcher;

youdao

想到一件物品在太空中停留那么久似乎令人惊讶，但目前仍在轨道上的最古老的卫星——先锋1号——在2018已年满60岁。

It might seem surprising to think about an item staying in space for that long, but the oldest satellite still in orbit—Vanguard 1—turned 60 in 2018.

youdao

现在，随着项目的继续，充当先锋的两颗卫星准备退休了。

Now, as the project proceeds, the pioneers are going to retire.

youdao