理查德·布蘭森(Richard Branson)的維珍銀河公司(Virgin Galactic)和他們的“太空船2號”(SpaceshipTwo)太空梭，傑夫·貝佐斯(Jeff Bezos)的“藍色起源”(Blue Origin)和他們的“新謝博德”(New Shepard)運載工具，標誌著人類太空飛行的新時代的開始。這兩個系統都能夠給客戶帶來難以置信的一生一次的體驗，帶他們到太空的邊緣，然後再回來。這將為兩種運載工具的乘客提供大約4分鐘的失重狀態和獨特的視野，這是不到600人所經歷過的。理查德·布蘭森和傑夫·貝佐斯都決定乘坐他們公司的飛機進行首次載人飛行。
Richard Branson’s Virgin Galactic and their SpaceshipTwo space plane, and Jeff Bezos’ Blue Origin with their New Shepard vehicle mark the start of a new era of human spaceflight. Both of these systems are capable of giving customers an incredible once in a lifetime experience, taking them to the edge of space and back. This will provide passengers on both vehicles approximately four minutes of weightlessness and a unique view, which less than 600 humans have ever experienced. Both Richard Branson and Jeff Bezos have decided to ride on the very first crewed flights of their company’s crafts.
什麼是亞軌道航天？
美國的第一次商業太空飛行始於2020年，當時 SpaceX 公司用獵鷹9號火箭和載人龍飛船將NASA宇航員鮑勃 · 本肯和道格 · 赫爾利送往國際空間站。這是一個稱為 DM-2的軌道級載人任務，與藍色起源和維珍銀河正在做的是完全不同的任務。軌道飛行和亞軌道飛行相比需要能力更強的火箭。軌道任務將有效載荷送入軌道，除非它點火機動離開軌道，否則不會在短時間內返回地球。
亞軌道太空飛行並沒有進入軌道，亞軌道可簡單理解為“小於軌道”，介於航空與航天之間。與軌道任務相比，這些火箭的目標不是進入軌道。它們是專門建造的太空旅遊航天器。嘲笑這些沒有到達軌道的火箭，就像嘲笑本田思域沒有大卡車那麼大的馬力一樣。亞軌道航天器的設計不是用來做軌道任務的。
重要的是，這些亞軌道航天器可以去太空！畢竟，要進入太空，它們只需要飛到離開地球大氣層的地方。這並不是大氣突然消失，而是慢慢消失，直到到達一個幾乎沒有大氣的高度。
What Is Suborbital Spaceflight?
The first operational commercial spaceflight from the United States was in 2020, when SpaceX took NASA astronauts Bob Behnken and Doug Hurley up to the International Space Station on their Crew Dragon spacecraft atop a Falcon 9 rocket. This was an orbital mission called DM-2 and is a completely different task than what Blue Origin and Virgin Galactic are doing. Orbital missions require a much more capable rocket than suborbital missions. Once orbital missions get their payload into orbit, it won’t come back down to Earth until it deorbits.
Suborbital spaceflight on the other hand doesn’t reach orbit, they’re just that, sub orbital; less than orbit. Compared to orbital missions, these rockets’ goals aren’t to get to orbit. They are purpose built space tourism machines. Poking fun of these rockets for not reaching orbit is like poking fun of a Honda Civic for not being able to pull as much as a semi truck. It’s not designed to do that.
The important thing is that these rides do go to space! After all, to go to space they just have to go up until they are out of Earth’s atmosphere. It’s not like the atmosphere suddenly stops, but it slowly fades away until they have reached an altitude where there’s practically no atmosphere.
軌道 VS 亞軌道的分界
太空的定義源自於沒有大氣層，但不是沒有重力。重力不會因為到達太空的高度而消失。在海拔100公里的高度，物體仍然受到地球引力的牽引，其作用力與海平面幾乎相同。具體來說，與海平面的9.8 m/s2相比，100km高度的重力加速度仍然是9.4 m/s2。
藍色起源公司的新謝潑德和維珍銀河公司的太空船二號或多或少的沿斜上方發射飛行。新謝潑德和太空船二號分別經過大約兩分鐘的加速和一分鐘的加速後，將關閉引擎，兩個飛行器將無動力向上滑行，做減速運動，達到最高海拔或遠地點，然後落回地球。在引擎關閉的那一刻，乘客將開始感受到失重。乘客將一直保持失重狀態，直到航天器再次進入大氣層並開始體驗氣動阻力。
Orbital VS Suborbital
Space can be defined as a lack of atmosphere, but not a lack of gravity. Gravity doesn’t stop by reaching space. At an altitude of 100 km, mass is still being pulled by Earth’s gravity with nearly the same force as at sea level. Specifically, gravity still pulls with 9.4 m/s2 of force, as opposed to the 9.8 m/s2 at sea level.
Both, Blue Origin’s New Shepard and Virgin Galactic’s SpaceShipTwo will launch more or less straight up. After about two minutes of acceleration for New Shepard and one minute for SpaceShipTwo, the engines will cut off and both vehicles will coast up, where they will hit their peak altitude or apogee, and then fall back down to Earth. At the moment the engines cut off, passengers will begin to feel weightless. Passengers will feel weightless until the spacecrafts begin to hit the atmosphere again and start to experience aerodynamic drag.
在遠地點，這些飛行器的速度幾乎為零，在一個短暫的時刻幾乎完全靜止不動。如果他們現在試圖透過進入軌道而留在太空中，他們將需要很大的軌道速度，大約以7.6公里/s的速度飛行，這大約是他們在上升過程中的峰值速度的8倍。飛行速度是決定軌道與亞軌道飛行的重要因素。
發動機關閉後，兩種航天器的乘客將體驗三到四分鐘的失重狀態。
“太空”的定義：卡門線是一個國際定義，標誌著空間的邊緣，定義為海平面以上100公里。美國對太空的定義是80公里高度，即產生升力所需速度超過軌道速度的高度。按照國際上的定義，這兩種飛行器中只有一種（藍色起源的新謝潑德）進入太空，儘管它們都會經歷失重狀態。
2.維珍銀河公司的太空船二號
理查德 · 布蘭森的維珍銀河公司是一家亞軌道旅遊發射公司，不要與維珍軌道混淆。維珍銀河公司和維珍軌道公司都隸屬於理查德 · 布蘭森的維珍集團。維珍軌道公司是一家小型衛星火箭發射公司，從一架叫做 Cosmic Girl 的波音747上發射LauncherOne 火箭。在過去，維珍軌道是維珍銀河的一部分，但現在是獨立的實體。
維珍銀河目前有一個由太空船二號和白騎士二號運載飛機組成的系統。維珍銀河還有一個更新的產品叫做太空船三號。它實際上和太空船二號是同一型空天飛機，但是在本文發表之前還沒有飛行過。
太空船二號和白騎士二號是由公司最初的太空船一號和白騎士一號按比例放大的版本。太空船一號和白騎士一號這兩艘飛行器由Scaled Composites公司公司製造，在短短五天內成功兩次進行太空往返飛行，贏得了2004年Ansari X大獎的1000萬美元。這一壯舉引起了理查德 · 布蘭森和維珍集團的注意，他們正在尋找太空旅遊的技術，並宣佈他們將在太空船一號首次動力飛行後授權這項技術並贊助太空船一號。
2005年，維珍銀河聯合Scaled Composites創立了太空船公司，維珍銀河擁有70% 的股份，Scaled Composites公司擁有30% 的股份。太空船公司的目標是擴大太空船一號及其運載飛機的規模，以最大限度地發揮其商業太空飛行潛力。
2008年，該公司推出新的白騎士二號飛機，比原來的白騎士一號大3倍。它採用了全雙機身設計，配有四個噴氣發動機。
白騎士二號飛機機身的一側是太空船二號內部的完美復刻，用於以合理的成本訓練乘客，而另一側機身可以用於高度18公里的廉價旅行。飛行高度幾乎是普通客機的兩倍，乘客足以看到深藍色的天空。
At apogee, these vehicles have virtually zero horizontal velocity. They are practically completely stationary for a brief moment in time. If they now were to try and stay in space by getting into orbit, they would need to be traveling at orbital velocities, roughly 28,000 kmh sideways, which is about 8 times faster than their peak velocity during ascent. A quick rundown on orbit vs suborbit can be found here.
Starting with engine cut off, passengers of both vehicles will experience weightlessness for three to four minutes.
Definition Of “Space”
The Kármán line is an international definition that marks the edge of space and is defined as 100 km above sea level. The US’ definition of where space begins is 80 km, which is the altitude where speeds required to generate lift are exceeding orbital velocity. By international definitions, only one of the two vehicles reaches space, although both will experience weightlessness.
Virgin Galactic’s SpaceShipTwo
Richard Branson’s Virgin Galactic is a suborbital tourism launch company that is not to be confused with Virgin Orbit. Virgin Orbit is a small satellite rocket company, which launches their LauncherOne rocket from a Boeing 747 called Cosmic Girl. At one point they both were part of Virgin Galactic, but are now separate entities. Virgin Galactic currently has one system composed of SpaceShipTwo and its carrier plane, WhiteKnightTwo.
There’s also a newer production-ready version called SpaceShip III (formerly SpaceShipThree). It is virtually the same spaceplane as SpaceShipTwo, but hasn’t flown by the time this article has been published.
SpaceShipTwo and WhiteknightTwo are scaled up versions of the original SpaceShipOne and WhiteKnightOne, which were built by Scaled Composites and won the 2004 Ansari X prize of 10 million US dollars by successfully flying to space and back twice in just five days. This feat won the attention of Richard Branson and the Virgin Group, who were looking for a space tourism option and announced that they would license the technology and sponsor SpaceShipOne after its first powered flight.
Virgin Galactic co-founded The Spaceship Company in 2005 at a 70% ownership, with Scaled Composites owning 30%. The Spaceship Company’s goal was to scale up SpaceShipOne and its carrier plane to maximize their commercial spaceflight potential.
In 2008 the company would roll out their new WhiteKnightTwo carrier plane, which was about 3 times larger than the original WhiteKnightOne. It now features a full twin fuselage design with four jet engines.
While one side of the fuselage is a replica of SpaceShipTwo’s interior, which is used to train passengers at reasonable cost, the other fuselage can be used for cheaper trips to 18 km. At almost double the altitude of a standard airliner, passengers will be high enough to see a dark blue sky.
2009年12月7日，第一艘太空船2號推出，命名為 VSS 企業號。它採用了更大的設計，能夠運送2名飛行員和6名乘客。它使用了獨特的混合動力火箭發動機的升級版本用於飛行高度爬升。
太空船二號的混合火箭發動機：
混合動力發動機使用端羥基聚丁二烯(HTPB)，一種固體火箭燃料，但不同於傳統的固體火箭發動機，它使用一氧化二氮作為氧化劑，使他們能夠在飛行中關閉發動機。這就是“混合”二字的由來。只有當液態或氣態 N2O 存在於發動機中時固體火箭推進劑才能保持燃燒。這使得飛行員能夠用點火器啟動發動機，一氧化二氮從氧化劑罐流入發動機的固體推進劑部分。儘管能夠主動關閉發動機，它不能改變噴嘴的推力方向。
在短暫的一段時間內，維珍銀河公司探索了一種叫做熱塑性聚醯胺的固體燃料的可行性，這種燃料含有一氧化二氮和甲烷(CH4)用於燃燒，而使用氦用於關機。在第一次也是唯一一次使用這種發動機的飛行之後，他們轉而使用 HTPB。不幸的是，在第一次也是唯一一次使用這種發動機的飛行中，兩名試飛員中的一人死亡，一人重傷，太空船二號飛行器悲劇性解體墜毀。
挫折與悲劇：
太空船二號的解體與這臺新發動機的使用無關。這次解體與它的一個主要設計——羽翼再入大氣層系統有關。當副駕駛以0.92馬赫的速度提前解鎖了該系統時，空天飛機解體了。施加於羽翼系統的空氣動力學和慣性負載超過了系統作動器，導致了飛行器的解體。
太空船二號的特性：
維珍銀河公司的太空船二號空天飛機的整體形狀和設計超級獨特，具有氣動傾斜的尾翼和水平穩定器。空天飛機的兩個尾翼有一個獨特的再入大氣層的外形，這個外形的靈感來自羽毛球。這種獨特的再入剖面設計是一種被動穩定的設計，利用氣動阻力使飛行器再入時腹部向下，即使是在它再入時姿態倒置也能被動糾正。
一旦飛行器處於亞音速狀態並再次進入大氣層，它就會將機翼拉直並滑回跑道進行相對標準的著陸流程。它不使用前起落架，而是使用一個簡單的剎車片，著陸時起到剎車的作用。
The first SpaceShipTwo, technically the first Scaled Composites Model 339 SpaceShipTwo, was revealed on December 7th, 2009, and was named VSS Enterprise. It sported a much larger design capable of ferrying 2 pilots and 6 passengers. On ascent it uses an upgraded version of their unique hybrid rocket engine.
SpaceShipTwo’s Hybrid Rocket Engine
The hybrid engine uses Hydroxyl-terminated polybutadiene (HTPB), a rubber based solid rocket fuel, but unlike a traditional solid rocket booster, it uses nitrous oxide (N2O) as oxidizer, which enables them to shut down the engine mid flight. This is where the “hybrid” comes from. The solid rocket propellant will only remain firing when liquid or gaseous N2O is present in the motor. This enables the pilots to light the engine with an ignitor, with N2O flowing from an oxidizer tank into the solid propellant part of the engine. Despite being able to turn the engine off, it cannot actively throttle.
For a short period of time, Virgin Galactic explored the viability of a different solid fuel called thermoplastic polyamide with N2O and methane (CH4) for combustion, while using helium for shut down. They would switch back to using HTPB after the first and only flight with that version of the engine, which unfortunately resulted in the tragic loss of one of the two test pilots and the vehicle.
Setbacks And Tragedy
The breakup of the spaceplane was not related with the use of this new engine. The breakup was related to a staple of its design, the feathered re-entry system. The spaceplane broke up when the Co-Pilot prematurely unlocked the feather system at Mach 0.92. Aerodynamic and inertial loads opposed on the feather system overcame the feather actuators, which resulted in the breakup of the vehicle.
SpaceShipTwo Specific Characteristics
The overall shape and design of Virgin Galactic’s spaceplanes is super unique, featuring pneumatically tilted tails and horizontal stabilizers. The twin tails of the rocket plane have a so-called carefree re-entry profile, which takes inspiration from a badminton shuttlecock. This carefree re-entry profile is a passively stable design that provides a large amount of drag and makes the vehicle want to re-enter belly down every time, even in the case of it re-entering upside down.
Once the vehicle is subsonic and in the lower portions of the atmosphere again, it straightens its wings back out and glides back to the runway for a relatively standard landing. Instead of a front landing gear, it uses a simple skid that also functions as a brake pad on touchdown.
沒有自動駕駛，依賴兩名專業的飛行員操作：
關於太空船二號最有趣的部分是，飛行員100% 控制他們。沒有自動駕駛儀，也沒有電傳飛行。兩名飛行員在超音速時透過電子控制舵直接控制飛行器，在亞音速時透過電纜和連桿機構直接控制飛行器。為了控制太空船二號在太空中的姿態，裝有12個冷氣推進器。冷氣推進器使用壓縮空氣，是在沒有大氣存在的情況下控制飛行器姿態的一種非常簡單有效的方法。可以控制俯仰，偏航和滾動，共有6對推進器冗餘。
客戶體驗：
維珍銀河密切關注飛行艙內的細節，並確保客戶最佳的體驗，安裝了16個攝像頭。顧客不必擺弄他們的相機和手機拍攝，幫助他們記錄飛行過程（發朋友圈，炫個富），專注於體驗。座椅有背顯示屏，以幫助客戶瞭解飛行每個階段的最新狀態。座椅也是動態調整的，可改變他們的角度，以在不同階段的飛行過程中最大限度地舒適和安全。此外，座椅還具有自收縮安全帶，以幫助乘客在失重狀態下離開座位。分佈有17個視窗，有圓角，乘客可以很容易地抓到窗戶邊緣。
2016年，維珍銀河建造了他們的第二艘太空船二號 VSS Unity。在為商業乘客飛行做好準備之前，它曾三次飛向太空。2021年3月30日，維珍銀河公司釋出了他們的第一艘名為 VSS Imagine 的太空船三號。
Humans At The Helm
The most interesting part about these vehicles is that humans are 100% in control of them. There is no autopilot and no fly-by-wire. The pair of pilots control the vehicle directly through electronically controlled trim at supersonic speeds, and cable and rod linkages at subsonic speeds. To control the orientation of the spaceplane in space, they have 12 cold gas thrusters. Cold gas thrusters use compressed air and are a very simple and effective way of controlling the attitude of a vehicle when there is no atmosphere present. They can control pitch, yaw and roll, with a total of 6 pairs of thrusters for redundancy.
The Customer Experience
Virgin Galactic pays close attention to detail inside the vehicle and ensures the customer the best possible experience by including 16 cameras. Customers will not have to fiddle around their cameras, helping them to live in the moment and focus on the experience. There are seatback displays to help staying up to date with every phase of the flight. The seats are also dynamic and change their angle to maximize comfort and safety during the different portions of the flight. Furthermore, the seats also feature self retracting seat belts to help passengers getting out of their seats quickly during weightlessness. There are 17 windows spread across the whole spaceplane with halo edges so passengers can easily get a hold on them.
In 2016, Virgin Galactic built their second SpaceShipTwo called VSS Unity. It flew three times to space before being ready for passengers. Five years later, Virgin Galactic presented their first SpaceShip III called VSS Imagine on March 30th, 2021.
藍色起源的新謝潑德
傑夫 · 貝佐斯的藍色起源已經建立了很長一段時間，甚至早於 SpaceX 公司成立，成立於2000年。藍色起源的哲學是“ Gradatim Ferociter”，這是拉丁語的“一步一步，兇猛”。他們緩慢而耐心的航天發展方式無疑反映出這一點。
新謝潑德的歷史與發展：
在新謝潑德火箭之前，在2006年藍色起源公司用一個名為戈達德的火箭動力飛行器展示了許多技術。在戈達德之後，藍色起源開始發展新謝潑德系統，它包括一個太空艙和一個一級火箭。
新謝潑德火箭是以艾倫謝潑德命名的，他是第一個進行亞軌道飛行的美國人。藍色起源的下一個火箭，新格倫，是以第一個進行軌道飛行的美國人約翰·格倫命名的，顧名思義，這個火箭將進行軌道飛行。
新謝潑德的太空艙在2012年底首次進行了發射中止系統的地面逃逸測試。藍色起源展示了他們的固體火箭發動機中止系統，以及在低空軟著陸時完全展開降落傘的能力。
航天器中央的大型中控臺結構並不是提供飲料瓜子的櫃檯，實際上是固體火箭發動機，能夠將太空艙推離失效的火箭，有助於航天器的安全。
Blue Origin’s New Shepard
Jeff Bezo’s Blue Origin has been around for a long time and was even founded before SpaceX in 2000. Blue Origin’s philosophy is “Gradatim Ferociter”, which is Latin for “Step by Step, Ferociously”. Their slow and patient approach to spaceflight development certainly mirrors that.
New Shepard’s History And Development
Before New Shepard saw the light of day, Blue Origin was demonstrating many technologies with a rocket powered vehicle named Goddard in 2006. After Goddard, Blue Origin began developing the New Shepard system, which is comprised of a space capsule and a booster.
New Shepard is named after Alan Shepard, the first American in space who performed a suborbital flight. Their next rocket, New Glenn, is named after John Glenn, the first American to go on an orbital flight, and as the name suggests, this rocket will be orbital.
New Shepard’s capsule was first tested at the end of 2012 with a pad escape test of their launch abort system. They demonstrated their pusher style solid rocket motor abort system and the ability to fully deploy the parachutes for a soft landing at low altitudes. The large center console looking structure in the middle of the spacecraft is actually the solid rocket motor capable of pushing the capsule away from a failed booster, aiding in the safety considerations of the vehicle.
結構與設計：
火箭和返回艙之間有一個環，它不僅在火箭重返期間保持空氣動力學穩定性，而且它也為逃逸發動機工作留出空間。這意味著，如果他們不得不在連線火箭時點燃逃逸發動機，逃逸火箭發動機產生的高溫氣體就會溢到到火箭的一側，從而降低受逃逸發動機高溫氣體影響火箭爆炸的可能性。
2015年，藍色起源公司宣佈他們已經完成了 BE-3發動機的驗收測試，該發動機將為新謝潑德火箭提供動力。BE-3是一種液氧液氫發動機。分離迴圈的特點是從主燃燒室中抽出熱氣體，熱氣體旋轉渦輪為推進劑泵提供動力。這不是一個容易啟動的發動機，因為燃燒只能在渦輪泵執行時發生，而渦輪泵需要燃燒發生執行等等（先有雞還是先有蛋）。
BE-3從海拔1200米的西德克薩斯州發射基地為火箭提供動力，一直到50公里處關閉，新謝潑德將繼續無動力滑向太空。在遠地點前80秒左右，火箭分離為兩個獨立的部件: 火箭一級助推器和太空艙。太空艙將再入大氣，下降速度慢於助推器。
在助推器下降過程中，助推器從頂部展開鰭來幫助引導它下降。在此之後，它部署了一些空氣剎車片，進一步幫助其減小速度。然後，在離地面僅3公里處，助推器重新點燃 BE-3發動機，減速下降。 BE-3發動機可以將推力控制在最大推力的20% 以下，這樣火箭就可以在目標著陸臺上懸停，並完美地重新調整方向。作為參考，SpaceX 公司的獵鷹9號和重型獵鷹的梅林發動機可以將推力調整至最大推力的40% 左右，這也是獵鷹9號不能執行懸停任務，只能減速降落到地面。
事實上，藍色起源的新謝潑德是第一個到達太空並在地面垂直回收的火箭，還早於SpaceX的獵鷹九號。在 SpaceX 公司的獵鷹9號助推器著陸前一個月，藍色起源就實現了垂直回收。當然，獵鷹九號火箭是軌道級火箭，最高時速可達8000公里，攜帶一個較大的上面級，而新謝潑德火箭是亞軌道火箭，最高時速約為3500公里/小時，直線上升，幾乎沒有水平速度。雖然新謝潑德只是一個亞軌道火箭，它的垂直著陸回收和重複使用仍然是一個值得注意的成就。
Structure And Design
The booster has a ring that the capsule sits on top of. Not only does it serve a purpose for aerodynamic stability during re-entry, but it also has reliefs for the abort motor. This means if they had to light the abort motor while attached to the booster, the hot gases from the rocket motor can escape to the side of the booster, lessening the chance of the booster exploding below it.
In 2015, Blue Origin announced they had completed acceptance testing of their BE-3 engine that would power the New Shepard booster. The BE-3 is a combustion tap-off cycle hydrolox powered engine. The tap-off cycle is charactarized by tapping off hot gasses from the main combustion chamber to spin the turbine to power the propellant pumps. It’s not an easy engine to start up as combustion can only occure when the pumps are running, which need combustion happening to run and so on and so forth.
The BE-3 is inefficiently splayed out on the base of New Shepard. Although the packaging isn’t tight and probably not as mass efficient, it is much easier to access the parts and potentially tweak or repair if necessary. This allows them to quickly refurbish and learn the engine inside and out, which further helps them shape their BE-3U vacuum optimized open expander cycle version that Blue Origin will utilize on their orbital New Glenn rocket in the future.
The BE-3 powers the rocket from their West-Texas launch site at about 1,200 m above sea level all the way up to about 50 km, when the vehicle hits main engine cut off and will coast the rest of the way up to space. Around 80 seconds before apogee, the vehicle stages into its two separate components, the booster and the capsule. The capsule will reenter and fall back down slower than the booster, which is skinnier with less surface area.
It’s during this portion of the mission that the booster deploys fins from the top ring to help steer it. After that it deploys some air brakes that are up around the top ring too, which further help to scrub off velocity. Then, at only about 3 km above the ground the booster re-lights its BE-3 engine to propulsively land. The engine can throttle down below 20% of maximum thrust, which allows the rocket to hover and perfectly redirect itself over its targeted landing pad. For reference, SpaceX’s Merlin engine on Falcon 9 and Falcon Heavy can throttle down to about 40%, which is also why the Falcon 9 can’t actually hover and has perform its fairly aggressive hover slam maneuver.
In fact, Blue Origin’s New Shepard was the first rocket to reach space and then propulsively land. They did this about one month before SpaceX landed their first Falcon 9 booster. Of course, one rocket is an orbital rocket booster travelling up to 8,000 kmh sideways carrying a large upper stage, while the other is suborbital, reaching a peak velocity of about 3,500 km/h, traveling straight up with virtually no horizontal velocity. Although New Shepard is ‘only’ a suborbital rocket, it was and still is a noteworthy accomplishment since landing rockets that go to space is not a trivial task.
與此同時，由於太空艙腹部表面積較大，再入大氣層返回速度較慢。在大約2公里的高度上，它部署了三個減速傘，在大約1公里的高度上部署三個主降落傘。儘管太空艙以每小時25公里的速度降落，但是著陸過程非常緩和，在最後一刻點燃制動推進器，從而在太空艙和地面之間形成一個很好的氣墊。這與俄羅斯聯盟號載人返回艙著陸時的情況類似。新謝潑德的太空艙實際上可以在兩個主降落傘失效時，降落速度緩慢到足以生存。這也要感謝減震座椅，它進一步幫助減輕震動。
不像太空船二號，新謝潑德是100% 自動化的。這意味著飛機上的所有六個座位都可以坐乘客，不需要飛行員。六名乘客中的每一位都緊挨著巨大的窗戶。它們是有史以來飛向太空的最大視窗，這是乘客在飛行中體驗的重要部分。
新謝潑德在把人類送上太空之前成功飛行了15次。他們在2015年初的第一次嘗試中失去了第一枚火箭，但太空艙安全返回。在那之後，第二個新謝潑德火箭在退役前飛行五次。第三個新謝潑德火箭在退役前成功飛行了七次，第四個新謝潑德火箭在準備進行第一次載人飛行之前飛行了兩次。
Meanwhile, the capsule has a slower return due to a larger surface area and blunt body re-entry. At about 2 km it deploys three drogue chutes, followed by its three main parachutes at just about 1 km in altitude. Despite the capsule coming down at only about 25 km/h, touchdown will even be softer than that by firing retro thrusters at the very last moment to create a nice cushion of air between the capsule and the ground. This is similar and comparable to what ROSCOSMO’s Soyuz capsules do when landing. New Shepard’s capsule could actually lose two of its main parachutes and stil land slow enough to be survivable. That’s also thanks to shock absorbing seats that further help with dampening the shock.
Unlike SpaceShipTwo, New Shepard is 100% autonomous. This means all six seats on board can be filled with passengers and there is no need for any of those seats to be taken up by pilots. Each of the six passengers are treated to massive windows. They are, at the time when this articles was published, the largest windows to ever fly to space, which are an important part of the passenger experience during flight.
New Shepard successfully flew 15 times before putting humans on board. They lost their first booster on their first attempt in early 2015, but still safely recovered the capsule. After that, the second booster would fly five times before being retired. The third booster and second capsule flew seven times successfully before being retired and then the fourth booster and third capsule flew twice before being ready to be the first to fly humans.
太空船二號 VS 新謝潑德
太空船二號長18米，翼展8.2米，尾翼4.6米。藍色起源的新謝潑德高19m，寬3.8m。作為參考，SpaceX 的獵鷹9號高70米，寬3.7米。
發動機
藍色起源公司的新謝潑德採用一個燃燒液態氫和液態氧的自迴圈發動機，而維珍銀河公司的太空船二號則配備了一個混合固體火箭發動機，燃燒固體燃料 HTPB，氧化亞氮作為氧化劑。
藍色起源公司的 BE-3比維珍銀河公司的 RocketMotorTwo 發動機產生的推力大約多出三分之一。由於 BE-3是一個 液體 發動機，它有一個相對較高的比衝。這些發動機的燃燒時間也大不相同，因為新謝潑德在地面發射，而太空船二號在空中發射。正因為如此，新謝潑德的 BE-3發動機執行時間約為2分20秒，而太空船二號只需要1分鐘。
SpaceShipTwo VS New Shepard
SpaceShipTwo is 18 m long with an 8.2 m wingspan and a tail height of 4.6 m. It’s about as long as New Shepard is tall, which is 19 m and about 3.8 m wide. For reference, SpaceX’ Falcon 9 is 70 m tall while being 3.7 m wide.
The Engines
Since both vehicles sport different engines, their stats differ as well. While Blue Origin’s New Shepard sports a combustion tap-off cycle engine burning liquid hydrogen (LH2) and liquid oxygen (LOx), Virgin Galactic’s SpaceShipTwo are fitted with a hybrid rocket engine burning the solid fuel HTPB with nitrous oxide (N2O) as oxidizer. Blue Origin’s BE-3 produces about one third more thrust than Virgin Galactic’s RocketMotorTwo at 490 kN and 310 kN respectively. Since the BE-3 is a Hydrolox engine, it has a relatively high specific impulse (ISP) compared to RocketMotorTwo’s ISP at 310 s and 250 s respectively. The burn time of these engines is quite different as well, due to the fact that New Shepard launches on the ground and SpaceShipTwo launches mid air. Because of this, New Shepard’s BE-3 runs for about 2 minutes and 20 seconds compared to just about one minute for SpaceShipTwo.
由於 BE-3是一臺液氧液氫發動機，它對環境的影響很小，因為燃燒產物只是水蒸氣。相比之下，太空船二號的火箭對環境的影響相當大，因為 HTPB 會破壞地球大氣層的臭氧層。
任務特徵
正如前面提到的，太空船二號可以攜帶八個人，包括兩名飛行員和六名乘客，而新謝潑德也可以攜帶六名乘客，不需要飛行員。與太空船二號相比，新謝潑德起飛到著陸的時間要短得多，只有大約十分鐘。太空船二號從起飛到著陸通常的飛行時間是大約兩個小時。大部分的時間要麼是騎著白騎士二號的漫長緩慢的爬升，要麼是緩慢的下滑。兩種飛行器在失重狀態下所花費的時間大致相同，大約為3到4分鐘。
這兩種飛行器之間另一個顯著的差別是它們的最大飛行高度。有史以來最高的 VSS Unity 飛行高度接近90公里，這意味著它從未越過卡門線邊界。另一方面，新謝潑德達到約105公里的遠地點。
可重用性降低成本
這些系統都是完全可重用的，這對於降低太空商業飛行的成本至關重要。
這兩類飛行器每張票的價格還沒有公佈出來。大多數預定太空船二號的人都花了25萬美元，但乘坐新謝潑德的價格還沒有公開。到目前為止，只有一個價格公佈了，那就是出價2800萬美元的一位顧客，將與傑夫 · 貝佐斯、他的兄弟馬克和航空界傳奇人物沃利 · 芬克一起參加首次飛行。在2019年的一次會議上，藍色起源的執行長鮑勃 · 史密斯建議每張機票的價格為“數十萬美元”，其他訊息來源稱，每張機票的價格將“遠遠超過50萬美元”。
Since the BE-3 is a Hydrolox engine, it has very little environmental impact as combustion products are only water vapor. In comparison, SpaceShipTwo’s RocketMotorTwo has a rather large environmental impact as HTPB damages the Ozon layer of Earth’s atmosphere. For more information on how much rockets pollute, please check out this video and/or article.
Mission Characteristics
As mentioned before, SpaceShipTwo can carry eight people, two pilots and six passengers, while New Shepard can also carry six passengers without the need of pilots. Compared to SpaceShipTwo, New Shepard is a much shorter ride with only about ten minutes from take off to landing. SpaceShipTwo’s usual flight time is about two hours from wheels up until touchdown. A lot of that time is either the long and slow climb while being attached to WhiteKnightTwo, or the slow glide back down. Both vehicles still spend roughly the same amount of time experiencing weightlessness of around three to four minutes.
One notable difference between the two vehicles is their maximum altitude. The highest VSS Unity has ever flown is just shy of 90 km, which does mean it has never crossed the Kármán line. Even though it is rather arbitrary, and doesn’t really change anything as far as the passenger experience goes, it is worth noting. New Shepard on the other hand reaches an apogee of around 105 km.
Reusability Brings Down Cost
Another important note about these systems is that they are both fully reusable. This is vital in bringing the cost of commercial spaceflight, even suborbital spaceflight, down and opening up the experience to more people than before.
The price per ticket for both vehicles is not something that is well published yet. Most people who have paid for rides on SpaceShipTwo have paid $250,000, but unfortunately, the price of a ride on New Shepard is not public yet. So far, there is only one example of price and it’s a customer who bid $28 million dollars to fly on the first flight alongside Jeff Bezos, his brother Mark, and aviation legend Wally Funk. On a conference back in 2019, Blue Origin’s CEO Bob Smith suggest a price per ticket in the “hundreds of thousands”, with other sources saying it will be “well north of $500,000”. At the publishing date of this article, no official price has been disclosed yet.
總結
維珍銀河公司的太空船二號(未來的太空船三號)和藍色起源公司的新謝潑德都提供了一個難得的太空邊緣旅遊的體驗，但同時又是兩個完全不同的系統。
一方面，新謝潑德的簡易火箭返回艙設計將客戶發射到卡門線之上，並在大約10分鐘內使用降落傘系統將他們安全降落。另一方面，維珍銀河公司複雜但優雅的空中發射混合火箭飛機，它將花兩個小時載客到達太空邊緣，然後再返回。當新謝潑德展示有史以來最大的太空窗戶時，太空船二號將顛倒過來，讓乘客可以回頭看地球。
兩個系統都有優缺點，可以滿足不同客戶的個人需求，它們都能提供差不多相同的3到4分鐘的失重體驗時間。
Conclusion
Both, Virgin Galactic’s SpaceShipTwo (SpaceShip III in the future) and Blue Origin’s New Shepard offer a great passenger experience focused ride to the edge of Earth’s atmosphere, while being two totally different systems.
On the one hand, there is New Shepard’s simple booster-capsule design catapulting customers above the Kármán line and landing them under parachutes in about ten minutes. On the other, there is Virgin Galactic’s complex but elegant air launched hybrid rocket plane that will take customers on a two hour round trip to the edge of space and back again. While New Shepard sports the biggest windows that have ever been to space, SpaceShipTwo will flip upside down, allowing passengers to look back down on Earth.
At the end of the day, both systems have advantages and disadvantages over one another that will fit the personal need of different customers, but, when it comes to experiencing weightlessness, they both offer nearly the same at around three to four minutes.