| 查看: 611 | 回复: 4 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
sgh_119至尊木虫 (职业作家)
|
[交流]
【Pure water】Discovery shuttle launch halted again after fuel leak
|
||
|
The planned launch of the space shuttle Discovery for its final mission has been postponed again after a fuel leak. After 26 years of service, the vehicle is due to make one last flight to the International Space Station (ISS) before being retired to a museum. Nasa has struggled all week to get Discovery off the ground, frustrated by poor weather and technical problems. Escaping hydrogen detected midway through fuelling left Nasa no choice but to stand Discovery down once more. The earliest another launch can be made is Monday. US politicians have confirmed that the reusable orbiters should give way to a new era of spaceflight, and one by one these remarkable vehicles are taking a final bow. Fleet leader Discovery is the oldest of the surviving ships. First launched in 1984, it has since completed 38 missions, travelling some 230 million kilometres in the process. Its commander on the final mission, Steve Lindsey, says Discovery is probably the most important of three remaining shuttles. "It is obviously a very historical vehicle, having flown the 'return to flight' test missions after both the Challenger and Columbia accidents," he said. "It deployed Hubble (and) it's the fleet leader in terms of number of flights - it'll have flown about a year on orbit by the time we're done with it, which is pretty remarkable for a space shuttle." After Discovery returns, only the Endeavour shuttle has a firm date to launch, in February next year. Atlantis could fly in June if the budget allows. Beyond that, American astronauts will use Russian Soyuz rockets to get into space until a range of commercial US launch systems are introduced in the middle of the decade. Technical challenges The hydrogen leak dicovered two hours into the fuelling operation is considered very serious by Nasa managers because of the potential flamability of the gas. A similar issue delayed two shuttle launches last year. Engineers now have to wait until the fuel that had been loaded in the giant external tank is drained before they can get on site to find the source of the problem and fix it. This means the earliest Discovery can now lift off is in three days' time, although managers conceded even this would be difficult to make. Monday is actually the last opportunity to fly this particular shuttle before a period of unfavourable sun angles begins at the orbiting platform, making a docking very difficult. A new launch window would not open until 30 November. Discovery's six astronauts had yet to board the spaceplane when the leak was detected. When the ship does get up, she will deliver a storeroom to be attached to the ISS, along with much needed supplies and spares. |
回复此楼» 猜你喜欢
一志愿东华大学控制学硕320求调剂
已经有3人回复
-
考研化学学硕调剂，一志愿985
已经有7人回复
-
333求调剂
已经有6人回复
-
化学工程321分求调剂
已经有21人回复
-
0703化学调剂
已经有15人回复
-
0703化学调剂 ，六级已过，有科研经历
已经有14人回复
-
326求调剂
已经有4人回复
-
311求调剂
已经有13人回复
-
311求调剂
已经有7人回复
-
材料与化工（0856）304求B区调剂
已经有7人回复
lxuyan
荣誉版主 (文坛精英)
拼搏到无能为力，努力到感动自
- ESEPI: 19
- 应助: 13 (小学生)
- 贵宾: 2.725
- 金币: 31170.3
- 散金: 32853
- 红花: 248
- 沙发: 431
- 帖子: 48932
- 在线: 2966.4小时
- 虫号: 519740
- 注册: 2008-03-06
- 专业: 制造系统与自动化
- 管辖: English Cafe
4楼2010-11-06 06:41:01
★
小木虫(沙发+1，金币+0.5):恭喜抢个沙发，再给个红包
小木虫(沙发+1，金币+0.5):恭喜抢个沙发，再给个红包
  |
2楼2010-11-06 01:21:44
shuwenhe
版主 (文坛精英)
冷月大师
- 应助: 18 (小学生)
- 贵宾: 2.145
- 金币: 49584.9
- 散金: 12156
- 红花: 50
- 沙发: 602
- 帖子: 36472
- 在线: 1904.6小时
- 虫号: 314293
- 注册: 2007-02-25
- 性别: GG
- 专业: 生物化学
- 管辖: 金融投资
5楼2010-11-06 07:13:44
