可重複使用的航天器

可重複使用航天器，顧名思義，是可重複使用的航天器，其設計須考慮重複發射、軌道、脫軌、大氣層再入。
可重複使用航天器的例子有太空飛機、航天飛機、航天飛機軌道器、逐夢者太空飛機、龍飛船的宇宙飛船。
此類系統的災難有：挑戰者號航天飛機災難、哥倫比亞號航天飛機災難。

**設計**

**Atmospheric entry**
Reusable spacecraft include mechanisms to deorbit and reenter the atmosphere in a controlled fashion. For this purpose, the 航天飛機 included 航天飛機軌道機動系統, and the 龍飛船 included its own engines, used for deorbiting. Deorbiting slows the spacecraft down, lowering its perigee to inside the atmosphere where the vehicle descends to Earth.
As a rough rule of thumb, 15% of the landed weight of an atmospheric reentry vehicle needs to be 防熱盾ing.
航天飛機隔熱系統s (TPS) can be made of a variety of materials, including reinforced carbon-carbon and 再入.  Historically these materials were first developed on ICBM 多目標重返大氣層載具s. However, the requirements of reusable space systems differ from those of single use reentry vehicles, especially with regards to 防熱盾 requirements. In particular the need for durable high 發射率 coatings that can withstand multiple thermal cycles constitutes a key requirement in the development of new reusable spacecraft. Current materials for such high 發射率 coatings include transition metal disilicides.
Ablative heat shields are reliable, but they can only be used once, and are heavy. Reinforced carbon-carbon heat tiles like those used on the Space Shuttle are fragile, and this was proved on the Space Shuttle Columbia disaster. Making a resistant yet lightweight and effective heat tile poses a challenge. The LI-900 material was used on the Space Shuttle.

**Landing and refurbishment**
Spacecraft that land horizontally on a runway require wings and undercarriage. These typically consume about 9-12% of the spacecraft mass,date=July 2020 which either reduces the payload or increases the size of the spacecraft. Concepts such as 舉升體 offer some reduction in wing mass,date=July 2020 as does the 三角翼 shape of the 航天飛機軌道器.
垂直起降 (火箭) can be accomplished either with parachutes or propulsively. 龍飛船 was an example of 宇宙飛船 with parachute reusability. Its derivative, 龍飛船2號, was originally intended to propusively land on land. However, such concept of reusability was canceled in 2017 and now Dragon 2 uses parachutes to land in the ocean.
After the spacecraft lands, it may need to be refurbished to prepare it for its next flight. This process may be lengthy and expensive, taking up to a year. And the spacecraft may not be able to be recertified as human-rated after refurbishment. There is eventually a limit on how many times a spacecraft can be refurbished before it has to be retired, but how often a spacecraft can be reused differs significantly between the various spacecraft designs.

**可重複使用航天器列表**

**US和歐洲太空總署**

**活躍**
太空船2號
*龍飛船2號
**Crew Dragon
**Cargo Dragon
*新雪帕德火箭
*X-37試驗機

**發展階段**
比較圖
*SpaceX星艦
*逐夢者太空飛機
*波音星際航線
*獵戶座飛船
*Space Rider
*SUSIE

**已退役**
 X-15試驗機- 雙子座計劃
** SC-2
*航天飛機軌道器
**發現號太空梭
**挑戰者號太空梭（挑戰者號航天飛機災難）
**哥倫比亞號太空梭（哥倫比亞號航天飛機災難）
**企業號太空梭（從未飛過太空）
**亞特蘭提斯號太空梭
**奮進號太空梭
*龍飛船

**已取消**
X-20試驗機
*赫爾墨斯號航天飛機

**俄羅斯 蘇聯**
 VA spacecraft
*暴風雪太空梭計畫軌道飛行器
**暴風雪號穿梭機
**小鳥號太空梭（從未飛過太空）
**2.01（從未飛過太空）
**2.02（從未飛過太空）
**2.03（從未飛過太空）

**發展階段**
鷹宇宙飛船

**已取消**
Kliper
*MAKS

**其它**
夢舟載人飛船
*RLV-TD

**發展階段**
阿凡達太空梭

**已取消**
HOPE-X

**參見**
 可複用發射載具

**參考 ==