美國發射最大絕密間諜衛星

According to the on November 22, the giant booster - a Delta Four Heavy rocket - blasted off at 5:58 pm from the Cape Canaveral Air Force Base in Florida carrying a new spy satellite NROL-32 for the US's National Reconnaissance Office into orbit on November 21.

NRO director Bruce Carlson said that the rocket would launch "with the largest satellite in the world on it." However, the exact purpose of the new spy satellite NROL-32 is secret。

For comparison, in July 2009 a satellite called TerreStar-One - touted as previous largest commercial satellite ever built– launched into space on July 7 in 2009. TerreStar-One is a 6, 9 kg satellite。

The Delta Four Heavy rocket is the US' biggest unmanned rocket currently and has two million pounds(about 0.91 million kg) of thrust, making it the most powerful liquid- fueled booster available currently. A Delta Four Heavy rocket stands 235 feet tall and is actually made up of three boosters。

The rocket made its first flight in 2004 and is capable of launching payloads of up to 24 tons into low-Earth orbit and 11 tons toward the geosynchronous orbits used by communications satellites。

In his address last month, Carlson said that the current plan for NRO satellite missions "is the most aggressive launch campaign that the National Reconnaissance Office has had in 20 years, almost a quarter of a century."據太空網站22日報道，21日下午5時58分，巨大的"德爾塔-4"重型火箭從美國佛羅里達州卡納維拉爾角空軍基地騰空而起，將美國國家偵察辦公室所屬的一顆絕密間諜衛星NROL-32送入軌道。

國家偵察辦公室主任布魯斯•卡爾森表示，"德爾塔-4"重型火箭將發射"世界上最大的衛星"。然而，這個最新間諜衛星NROL-32的具體性能卻是一個謎。

此前世界上最大的衛星是2009年7月發射的TerreStar-1商業衛星，重達6.9噸。

"德爾塔-4"重型火箭是美國現在最大的無人駕駛火箭，具有兩百萬磅(約91萬公斤)的推力，這讓它成爲目前最強大的液體燃料助推器。"德爾塔-4"重型火箭高235英寸，實際上是由三個助推器組成。

重型火箭在2004年進行首次發射，它可以將24噸重的負載發送到低地球軌道，也能將用於通訊衛星的11噸重的載荷送入地球同步軌道。

在上個月的報告中，卡爾森表示，目前國家偵察局衛星計劃的使命是"國家偵察局20多年以來，幾乎算四分之一個世紀以來最具進攻性的發射活動"。