永不落地的无人机

    不过最关键的也许不是它的飞行方式，而是它到底在何处飞。为了维持这么长的飞行时间，这种飞行器将在大气层的最佳位置即所谓的对流层顶飞行。这个区域距海平面约65,000英尺（即12英里多），风速通常小于5节。泰坦的工程师称，这个空域相对平静，且远高于湍流或其他会影响其飞行性能的恶劣天气，Solara可以在其中飞上五年之久。对流层顶下的天气会损坏普通飞行器，对Solara来说更关键的还在于，它会遮蔽太阳，因此在远高于这种天气的对流层顶飞行Solara就不易损坏。

    泰坦的工程师称，由于这种飞行器机械结构简单，同时还有足够的太阳能驱动它长期运行，因此现在限制飞行时长的因素就只有电池了。而电池会随着时间推移而逐渐老化，每隔几年就必须更换。为了论证这个问题，公司现在用两架五分之一大小的试验机进行试飞——同时推迟了B轮融资——到明年春季或夏季时才会让全尺寸机型上天。

    桑德斯表示，到公司交付首架飞机时——最快要到明年年底——太阳能板和电池技术也许已大幅提高，可让飞机飞行时间更长或携带更大载荷。他说：“我们正为了这个目标致力于开发最简单、最轻量化的解决方案，同时努力避免过分复杂化。这才是让这款无人机物美价廉、同时能够不间断飞行数年的关键所在。”

    当然，泰坦能否成功，至少在美国很大程度上取决于联邦航空管理局（FAA）是否允许这种飞行器在国家空域中飞行。目前允许无人机进入国家空域的管理规定还未出台（相关制度将于2015年推出），针对像Solara这样大型无人机的管理制度应该会非常严格。

    不过桑德斯及公司对此并不怎么担心，因为在该机型的设计研发全程中泰坦都与联邦航空管理局保持着密切合作。而从技术上说，虽然这个机型的飞行寿命长达数年，但联邦航空管理局真正关心的只是其最初爬升的那一段。桑德斯称，美国的A级空域最高到60,000英尺为止，超过高度就不是联邦航空管理局管辖的范围了（这个高度大概是民用飞机飞行高度的两倍）。

    桑德斯谈及这家年轻的公司（桑德斯32岁，创始人兼首席技术官马克斯•雅尼35岁左右，首席运营官尼克•雷诺德只有24岁）时表示，尽管符合现行飞行管理规定势在必行，但这不是泰坦公司真正的动力所在。这就是为什么公司称其产品为大气层卫星而不是无人机的缘故。在某种程度上，泰坦是要拿出一种截然不同、比现有产品更容易使用的产品来冲击无人机和卫星领域。

    桑德斯说：“我们不希望它带来任何运行成本，不想客户为了让一台不像样的飞行器获准飞行而不停地大笔花钱。”

    “我们想打造一台非常简单的产品，它能持续飞行，无需占用客户大量时间和精力。如果只需要有一个人监控飞行器，那就会让局面彻底改观。我们是要努力改变大家对飞行器运行方式的普遍看法。”（财富中文网）

    译者：清远

    But perhaps the most important part of the formula is not how it will fly, but where. To sustain such long flight durations, the aircraft will operate in an atmospheric sweet spot known as the tropopause, a zone at roughly 65,000 feet (or more than 12 miles) above sea level where winds are generally less than 5 knots. In this relative calm far above any turbulence or weather that would otherwise challenge its flight capabilities, Solara could linger for up to five years, Titan engineers say. It doesn't hurt that the tropopause resides far above the weather that can damage conventional aircraft or, more critically for Solara, block out the sun.

    With rather simple mechanical systems and enough solar power to run them indefinitely, the thing limiting flight duration right now is the batteries themselves, Titan engineers say, which deteriorate over time and must be swapped out every few years. To prove it, the company has two fifth-scale test aircraft currently conducting test flights and -- pending a round of Series B funding -- will have a full-sized prototype in the air by spring or summer of next year.

    By the time the company delivers its first aircraft -- which could happen as soon as the end of next year -- solar cell and battery technology may have improved such that the aircraft can extend their flight durations or carry even more payload, Sanders says. "We're focusing on the simplest, most lightweight solution for this and trying not to get overly complicated," he says. "That's really the key to keeping this thing affordable as well as to enable it to stay up there for years."

    Of course much of Titan's success, at least in the U.S., hinges on the FAA clearing the aircraft to fly in the national airspace. While rules governing UAS integration into the national airspace are pending (delivery of a regulatory framework is slated for 2015), the rules attached to larger UAS like the planned Solara are expected to be fairly strict.

    But Sanders and company aren't particularly worried. Titan has been working closely with the FAA through its design process, and anyhow the only part of that multi-year duration the FAA is technically concerned with is the initial climb. Class A airspace ends at 60,000 feet in the U.S.; above that the FAA doesn't regulate, Sanders says (that's roughly twice the altitude that commercial airliners operate).

    But while fitting into the existing flight paradigm is necessary, that's not really the driving idea behind Titan, Sanders says of the young startup (Sanders is 32, founder and CTO Max Yaney is in his mid-30s, and chief operating operator Nick Renold is 24). That's why the company refers to its products as atmospheric satellites rather than UAS. In a way, Titan is trying to hack the UAS and satellite space by providing something radically different and far more accessible than what's already out there.

    "We don't want any operating costs, we don't want you to spend thousands and thousands and thousands of dollars just to get the stupid thing certified all the time," Sanders says.

    "We want something very simple and that doesn't take up all of your time and energy to keep it running. If all you need is one person to keep an eye on the aircraft, that completely changes things. We're trying to change the mindset on how aircraft should operate."