Editing Simplified Aid For EVA Rescue

{{Short description|Device used for untethered spacewalks during the Space Shuttle and ISS programs}}
[[Image:STS-131 EVA3 Rick Mastracchio 2.jpg|thumb| 190 px|Astronaut [[Rick Mastracchio]] working with a SAFER system attached.]]
[[Image:SAFER - Simplified Aid for EVA Rescue 2.jpg|thumb|SAFER]]

'''Simplified Aid For EVA Rescue''' ('''SAFER''') is a small, self-contained, propulsive backpack system ([[jet pack]]) worn during [[spacewalk]]s, to be used in case of emergency only. If an untethered astronaut were to lose physical contact with the vessel, it would provide free-flying mobility to return to it. It is worn on spacewalks outside the [[International Space Station]] (ISS), and was worn on spacewalks outside the [[Space Shuttle]]. So far, there has not been an emergency in which it was needed.<ref name="day8-92">{{Cite web|url=http://science.ksc.nasa.gov/shuttle/missions/sts-92/sts-92-day-08-highlights.html|title=STS-92 Day 8 Highlights|access-date=October 6, 2008|publisher=NASA|year=2000|author=NASA}}</ref><ref name="A Flying Astronaut Over Earth">{{Cite web|url=http://www.sai.msu.su/apod/ap011002.html|title=Astronomy Picture of the Day A Flying Astronaut Over Earth  |access-date=October 6, 2008|publisher=NASA|year=2001|author=APOD}}</ref> SAFER is a small, simplified version of the [[Manned Maneuvering Unit]] (MMU), which was used for regular maneuvering.<ref name="assembly">{{Cite web|url=http://images.jsc.nasa.gov/luceneweb/caption.jsp?searchpage=true&keywords=SAFER&textsearch=Go&hitsperpage=5&pageno=3&photoId=S93-50137|title=SAFER Assembly|access-date=October 6, 2008|publisher=NASA|year=1993|author=NASA|url-status=dead|archive-url=https://web.archive.org/web/20110613224209/http://images.jsc.nasa.gov/luceneweb/caption.jsp?searchpage=true&keywords=SAFER&textsearch=Go&hitsperpage=5&pageno=3&photoId=S93-50137|archive-date=June 13, 2011}}</ref>

== Description ==
SAFER is fitted around the life support backpack of the space suit (EMU or [[Extravehicular Mobility Unit]]). SAFER in no way interferes with suit mobility. The flight test unit was fitted with a single hand control module rigidly attached to the Display and Control Module (DCM) in front of the suit. The hand controller provided six degrees-of-freedom (DOF) maneuvering via 24 gaseous-nitrogen (GN2) thrusters. Vehicle weight is 85 pounds. The GN2 is stored in four cylindrical tanks, each charged to 3250 psi. Total fuel capacity is 3 pounds which is sufficient to change the vehicle velocity approximately 10 feet/second (ΔV). The unit features very extensive [[self-test]] capability.<ref>{{Cite journal |last=Meade |first=Carl |date=October 1995 |title=First Flight Test Result of the Simplified Aid For EVA Rescue (SAFER) Propulsion Unit |url=https://www.researchgate.net/publication/319601444 |journal=International Space Station}}</ref>

==Application==
SAFER is designed to be used as a self-rescue device if in spite of precautions such as tethers, safety grips, and the robot arm an EVA crewmember gets separated and no vehicles can provide rescue capability.<ref name="nyt">{{cite news|url=https://query.nytimes.com/gst/fullpage.html?res=9A05E5D61F38F933A2575AC0A962958260|title=Shuttle Soars Into Orbit to Test Device for Space Rescues | page = 7 | access-date=October 6, 2008|work=[[The New York Times]]|author=Broad, William J. | date=September 10, 1994}}</ref> SAFER is worn by every ISS crewmember using an [[Extravehicular Mobility Unit]]. 

SAFER was co-invented by former astronauts [[Joseph P. Kerwin|Joseph Kerwin]], Paul Cottingham and Ted Christian under a Lockheed contract to NASA for [[Space Station Freedom]].{{cn|date=June 2020}} It was later{{when|date=June 2020}} sponsored by the Space Shuttle Program and developed by [[Lockheed Corporation|Lockheed]] and NASA personnel. SAFER was the design solution to the Shuttle Program's requirement to provide a means of self rescue should an EVA crewmember become untethered during an EVA.<ref name = "STS-92 Press Kit">
{{cite press release
| author       = United Space Alliance Staff 
| title        = STS-92 – DISCOVERY: DELIVERING FRAMEWORK FOR FUTURE SPACE STATION GROWTH
| url          = https://www.nasa.gov/wp-content/uploads/2023/05/sts-092-press-kit.pdf?emrc=40d488
| url-status   = live
| page         = 39
| location     = Houston
| publisher    = NASA
| date         = October 2, 2000
| archive-url  = https://web.archive.org/web/20240207210838/https://www.nasa.gov/wp-content/uploads/2023/05/sts-092-press-kit.pdf?emrc=40d488
| archive-date = February 7, 2024
| access-date  = February 7, 2024
}}</ref>

SAFER was first flown on [[STS-64]] September 9, 1994, where an untethered flight test was performed first by astronaut [[Mark C. Lee|Mark Lee]] and then [[Carl Meade]].<ref name="nyt" /> Both astronauts flew the SAFER up and around the Shuttle's [[Canadarm|Robotic Arm]] along with a demonstration test of the SAFER's automatic attitude hold feature.  This feature arrests uncontrolled rotation of a detached crewmember expected in an accidental separation.  SAFER has a mass of approximately 83&nbsp;lb (38&nbsp;kg) and can provide a total change in velocity ([[delta-v]]) of at least 10&nbsp;ft/s (3&nbsp;m/s).<ref name="nyt"/> It was also tested during flight [[STS-92]] when astronauts [[Peter Wisoff]] and [[Michael López-Alegría]] performed test maneuvers, flying up to 50 feet (15&nbsp;m) while remaining tethered to the spacecraft.<ref name = "STS-92 Mission Report">
{{cite report
 | date         = October 18, 2000
 | title        = STS-92 Mission Control Center Status Report
 | url          = http://science.ksc.nasa.gov/shuttle/missions/sts-92/news/sts-92-mcc-15.txt
 | publisher    = NASA 
 | format       = HTML
 | edition      = 15
 | location     = Houston
 | access-date  = February 7, 2024
 | archive-url  = https://web.archive.org/web/20081021074233/http://science.ksc.nasa.gov/shuttle/missions/sts-92/news/sts-92-mcc-15.txt
 | archive-date = October 21, 2008
 | url-status   = dead
}}</ref>

==Complications==

The left side latch on the SAFER unit became unlatched during an EVA by astronaut [[Piers Sellers]] on [[STS-121]] while testing shuttle repair techniques.<ref name="msnbc">{{Cite web|url=http://www.nbcnews.com/id/13815044|archive-url=https://web.archive.org/web/20140329012427/http://www.nbcnews.com/id/13815044/|url-status=dead|archive-date=March 29, 2014|title=Duct tape suggested for spacewalk repair|access-date=October 6, 2008|publisher=[[NBC News]]|year=2006|author=Mike Schneider for the Associated Press}}</ref><ref name="drama">{{Cite web|url=https://www.newscientist.com/article/dn9524-high-drama-spacewalk-ends-in-success.html|title=High drama spacewalk ends in success|access-date=October 6, 2008|publisher=New Scientist|year=2006|author=Kelly Young}}</ref> The latch had been inadvertently bumped and moved to the unlatch position.  As a precaution, [[Mike Fossum]] tethered it to him and the spacewalk continued.<ref name="spacecom">{{Cite web|url=http://www.space.com/missionlaunches/060712_sts121_eva3.html|title=Spacewalkers Test Shuttle Heat Shield Repair Technique |access-date=October 6, 2008|publisher=Space.com|year=2006|author=Tariq Malik}}</ref> In subsequent spacewalks, the latches were secured with [[Kapton]] tape, a space-rated form of [[adhesive tape]], to prevent the latches from inadvertently opening.

==See also==
*[[Single-person spacecraft]]

==References==
{{Reflist|2}}

==External links==
* {{cite book|title=Suited for spacewalking a teacher's guide with activities for technology education, mathematics, and science.|url=https://books.google.com/books?id=nv4w6IuEbNMC&pg=PA34|publisher=DIANE Publishing|isbn=978-1-4289-2748-3|page=34}}
* [https://www.youtube.com/watch?v=32MRnh9dsv0 Video of SAFER being attached]

{{space suit}}

[[Category:Human spaceflight]]
[[Category:Extravehicular activity]]