Astronomy:Orbital replacement unit (HST)
An orbital replacement unit or orbital replaceable unit is a modular component of spacecraft that can be replaced upon failure either by robot or by extravehicular activity. The Hubble Space Telescope (HST) was designed with 70 such parts,[1] including scientific instruments and limited-life items such as batteries.[1]
On HST some parts were designed from the start as ORUs and all used captive bolts with a standard 7/16" double-height hex head;[2] later when it was decided to avoid returning HST to Earth for repair, more systems and modules were designated as ORUs (but used a wider variety of fasteners).[2] HST servicing mission 3A (SM3A) replaced (or added) 15 ORUs,[2]:fig 2-1 e.g. it replaced the DF-224 computer with the Advanced Computer.
The electrical system of the International Space Station also has such subsystems that provide power generation, power distribution and energy storage.[3]
See also
- Hubble Space Telescope § Servicing missions and new instruments
- Orbital replacement unit, about the ISS ORUs
References
- ↑ 1.0 1.1 Kinard, William H.. "Returned Hardware: Orbital Replacement Units". Hubble Space Telescope Archive System. NASA / Langley Research Center. Archived from the original on 19 February 2013. https://web.archive.org/web/20130219022932/http://setas-www.larc.nasa.gov/HUBBLE/HARDWARE/hubble_ORU.html. Retrieved 27 March 2013.
- ↑ 2.0 2.1 2.2 "Hubble Space Telescope Servicing Mission 3A Media Reference Guide" (PDF). NASA. https://asd.gsfc.nasa.gov/archive/hubble/a_pdf/news/SM3A-MediaGuide.pdf. Retrieved 21 September 2010. Section 2.2.
- ↑ "Glenn Leads Sustaining Engineering of Power System Hardware". NASA / Glenn Research Center. 14 February 2008. Archived from the original on 22 February 2012. https://web.archive.org/web/20120222024245/http://spaceflightsystems.grc.nasa.gov/print/eps_prt.htm. Retrieved 27 March 2013.
 |  |
