美宇航局高薪聘長期臥牀志願者

Are you someone who will happily spend days sprawled on your sofa watching TV?

Or could you sit in the same spot for hours with only a computer game for company?

If you answered yes to any of the above questions, then the future of human space travel could rest with you.

Nasa is recruiting volunteers to lie a bed for 70 days to research the effects of microgravity on the human body.

And the study, which is on-going, will give you around £3,137 ($5,000) a month for the pleasure.

The study takes place at the Johnson Space Centre in Houston where you stay for two weeks, doing every day activities, so that scientists can monitor your body in normal conditions.

You then spend 70 days in a tilted bed where you will have light for 16 hours per day and darkness for eight hours per day.

Access to computer games, TV, books, the internet and visitors is permitted, and all food is provided to keep you at a constant weight.

You can even get a shower while you’re in bed.

The only time you can move is when scientists carry out tests to find out any changes in bone, muscle, circulation, nutrition and the immune system.

Or as part of the newly-introduced exercise called the ‘countermeasure and function testing’ study, that will monitor how different movements can effect muscle size and strength, bone health, and cardiovascular function.

Even then you will be lying in bed and will exercise on specially-designed equipment.

Following 70 days, there is a 14-day rehabilitation period to get your body back into shape.

If all this sounds like your dream come true, applications can be made here.

Self-described ‘pillownaut’ Heather Archuletta has taken part in the study three times.

‘I'm a very active person, so it's difficult to be restricted to bed sometimes, but many of us are willing to do it for the sake of future space exploration,’ she wrote on her blog.

‘The... money... is... pretty freaking awesome, however. About $5,000 per month, which is great if you've just graduated, can't find a job, are between jobs, or just plain love space exploration,’ added Ms Archuletta.

A similar study is being undertaken by the European's Space Agency's (ESA) Programme for Life and Physical Sciences at the Medes Institute in Toulouse, France.

But while it may sound like easy money, it isn’t the walk in the park that it might first seem.

During extended periods, microgravity takes a serious toll on the human body.

Without the pulls of normal gravity, blood doesn't flow downhill, but pools in the extremities including the face, hands and feet, causing a puffy appearance.

And without that downward pressure, height increases.

Body mass often decreases with a loss of muscular tissue from nitrogen depletion; the veins and arteries of the legs become weaker, anaemia occurs, accompanied by a reduction in blood count.

The most serious concern is the loss of bone calcium that increases with the length of a mission.

The calcium loss from bones subjected to extended microgravity takes place at 10 times the rate of an elderly person suffering from osteoporosis.

Astronauts report an overall feeling of weakness and loss of balance upon return to Earth, though recovery is nearly complete after a week.

Researching the effects of microgravity has been an on-going programme at Nasa for the past 25 years.

There are a number of other ways to create low-gravity environments on Earth for research, but these last for short periods of time.

For instance releasing experiment samples from tall drop towers provides about four seconds of microgravity.

Research aircraft can expose experiments to about 30 seconds of low-gravity while the aircraft approaches the top of a steep climb and begins a sharp descent.你喜歡整天躺在沙發上看電視嗎？願意坐在一個地方玩上數小時的遊戲嗎？如果答案是肯定的，那麼恭喜你，你可以申請成爲美國航空航天局的志願者了。

據英國《每日郵報》9月16日報道，美國國家航空航天局（NASA）正在招聘臥牀70天的志願者，用以研究微重力對人體的研究。志願者將獲得每個月5000美元左右的報酬。

這項研究在休斯敦的約翰遜航天中心進行，志願者將在那裏待上兩週，做一些日常活動，讓科學家檢測其在正常情況下的身體狀態。

接下來，志願者將在一個傾斜的牀上躺上70天，每天有16個小時可以見到光，另外8小時則要在黑暗中度過。當然，你可以玩電腦遊戲、看電視、看書、上網、會客，獲得定量的食物供給，甚至可以在牀上淋浴。

然而，只有在研究人員前來檢查骨頭、肌肉、血液循環、營養和免疫系統的變化時，志願者才能移動。即便在那個時候，志願者也只能躺在牀上，並接受特製設備的檢驗。

70天后，志願者會接受一個14天的康復期，讓身體恢復正常。

三次參加該實驗的希瑟•阿楚萊塔在博客上寫道：“我是一個很活躍的人，所以被困在牀上很難受。但是很多人都願意爲了未來的太空探索去做這個實驗。報酬還是很豐厚的，大約5000美元一個月。如果你剛畢業，找不到工作，剛辭去上一份工作又沒找到下家，或者僅僅是熱愛太空探索，都可以去報名參加。”

儘管聽上去很容易，但該實驗絕不像在公園散步那麼簡單。長期看來，微重力會對人體產生嚴重不良影響。血液無法往下流，而是停留在臉部和手足等處，造成浮腫；肌肉組織會隨着氮源的消耗而減少，體重隨之減輕；腿部的靜脈和動脈變弱；隨着血細胞減少，將出現貧血症狀；骨鈣大量流失。

微重力是指重力或其它的外力引起的加速度不超過10e-5～10e-4g。太空環境就是微重力環境。據報道，NASA在過去25年裏一直在研究微重力的影響。