收到一条中英双语短信，竟然是外卖小哥发来的！近日，有网友在微博爆料称：武昌汉街附近一外卖送餐小哥用中英双语发信息与顾客沟通。许多网友感叹，外卖小哥都在使用英语了，你还有什么理由不努力？为励志的外卖小哥点赞。

   所以，今天，浮空君决定整点不一样的。反正关注咱们浮空飞行器的都是高学历，高收入，高颜值人群，英文原文读起来更流畅。

Long-duration stratospheric research missions could allow scientists to collect vast amounts of data continuously for their payloads. Such missions could benefit NASA by maturing future space technology as well as allowing for Earth observations, such as storm monitoring and forest fire tracking.

The World View Stratollite consists of a primary lift balloon (top), secondary balloons (middle), a solar panel power generation and distribution system, and a stratocraft payload-carrying structure (bottom).

Credits: World View

Previously, technological challenges have limited the duration of balloon flights in the stratosphere due to the lack of trajectory control necessary for longer flights. Now, a system developed by World View Enterprises promises the capability to perform large altitude changes to achieve meaningful trajectory control of balloon flights in the stratosphere.

World View’s novel altitude control technology was selected to receive funding through NASA’s Research Announcement: Space Technology – Research, Development, Demonstration, and Infusion (REDDI) 2016 solicitation. This summer, the company performed flight tests that demonstrated this system’s capability, which put World View one step closer to shifting the status quo of lack of altitude control.

“This really is an enabling technology and platform for testing science payloads,” said World View’s Iain Beveridge, principal investigator. “Now a lot of payloads may be interested in altitude control so they can put their payloads in the stratosphere and gather data continuously. We call it persistent coverage over an area.”

World View has been persistent in its development of the altitude control technology, just one component in a complex network of advances making up the company’s Stratollite system.

“The Stratollite basically acts as a satellite for the stratosphere, but actually gives you more coverage,” Beveridge explained. “During large portions of the year, we’re able to sustain coverage within about 100 miles of a target to keep our instruments looking at that specific point.”

During the company’s summer 2017 demonstrations on the Stratollite, all proposed success criteria were met. These criteria included demonstrating altitude changes, maintaining altitude levels during periods of both high and low solar elevation, and showing that the system is able to perform station keeping over a 24-hour flight.

“Our last Stratollite mission was a massive win for World View and completed another successful milestone in the development of the Stratollite,” said Beveridge. “As far as I know, this is the first high-altitude balloon vehicle to perform a controlled altitude change of this magnitude within the stratosphere.”  

The 27-hour flight out of Page, Arizona, continued into California before maneuvering into westerly winds to guide the vehicle back toward Arizona.  In addition to achieving its primary objectives, the vehicle also performed a large altitude excursion of 25,000 feet, limited only by the commercial airspace ceiling. The flight test raised the technology readiness level (TRL) of the Stratollite system to 9.

With development dating back to 2012, the Stratollite’s altitude control system is the result of extensive research into state-of-the-art methods to traverse the stratosphere while catching the varying directions of the winds needed by flights throughout the year.

“One of the biggest advantages we now have over other systems is that we have a vast altitude range for station keeping,” Beveridge said. “It is more difficult the higher you go because of the density of the air, but based on our testing it does look like oursystem will go 90K feet or above, and then still be able to perform down to the 50,000-60,000-foot range.”

By making meaningful shifts between altitudes as needed within a given trajectory, World View’s system may be able to support much longer balloon missions than previously possible.

“The end goal is to be able to fly these for six, nine, even 12 months at a time,” Beveridge said. “So researchers can gather 6 months of data and have a very high level of confidence that their system is going to work.”

The implications for scientific payload testing are significant. “The operational cost of these flights is less than 1% of the cost of sending those payloads to space,”explained Beveridge.

Paul De León, campaign manager for NASA’s Flight Opportunities program, agrees that this technology has the potential to enable missions to be more efficient. “Rather than flying multiple flights, researchers may be able to achieve their goals with a single long-duration flight. This capability will also enable experiments requiring long-term exposure, which are currently very difficult to achieve.”

In addition to saving time, cost, and complexity for science missions, the value beyond payload testing is also clear. “Instead of sending an aircraft over a hurricane, you can use trajectory control on a Stratollite to hover above the hurricane and monitor it constantly as it evolves,” said Beveridge. “You can also use it for forest fire tracking, disaster relief efforts, maritime surveillance, or possibly homeland security missions.”

World View is continuing development of this ground-breaking capability and has more flights scheduled later this year to test different mission scenarios, longer duration, and higher altitudes. Looking forward, World View’s flight manifest for 2018 includes an increasing number of payload providers interested in this platform capability.

Through the Flight Opportunities program, the Space Technology Mission Directorate (STMD) selects promising technologies from industry, academia and government and provides opportunities for testing and technology demonstration on commercial launch vehicles. The program is managed at NASA's Armstrong Flight Research Center in Edwards, California. STMD is responsible for developing the crosscutting, pioneering new technologies and capabilities needed by the agency to achieve its current and future missions.

For more information about the Flight Opportunities program, visit:

https://www.nasa.gov/flightopportunities

   既然是双语送餐，浮空君就简单翻译一下：

       最近world view公司做了个试验，这个试验可厉害了，他们的高空气球飞了27个小时，但这不是最重要的，重要的是他们测试了高度调节技术，能调多少呢？7.5km！这个数字大家可能没感觉，给大家一个参考，谷歌的project loon项目的超压气球高度调节技术算是比较成熟了，飞了成千上万次了，它的高度调节能力是多少呢？2km左右。显然调节能力越强，就越有可能找到合适的风层进行航向控制。而且人家world view的老板说了，要不是怕飞到民航的航线上，我们还能调的更低，关键是还能调回来。从15公里到24公里之间都可以自由飞翔，你说神奇不神奇。

     按照他们老板的话说，world view的Stratolite项目是首个具有如此强的高度调节能力的大型高空气球，一点毛病没有，谷歌loon那1000立方米小气球根本就弱爆了。有了Stratolite，科学家们让自己的科学载荷搭载持续飞行1年以上，这可比100次的零敲碎打强100倍，成本却只有卫星的1%不到，你说气人儿不？当然，还不止科学试验，你还可以跟踪飓风，森林防火，边境警戒，反恐处突，应急救灾，无所不能呢。

      不过人家就是没说是怎么实现的，商业机密！

       给大家放一张图，自己想象一下。

     stratolite项目得到了NASA的"飞行良机"项目的大力支持，在此表示感谢。后者是NASA力推的提高技术成熟度的项目集，科学家们可以采用很多私营公司提供的低成本飞行平台进行空间新技术的测试，以提高其技术成熟度。

    对了，world view老板还说了，明年还要安排很多很多试验，档期都排满了，所以，载人太空观光的事先放放吧。