USA-165 or XSS-11^[2] (Experimental Satellite System-11) is a small, washing-machine-sized, low-cost spacecraft developed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate to test technology for proximity operations. In particular, the satellite was designed to demonstrate "autonomous rendezvous and proximity maneuvers." In other words, it would approach, investigate, and photograph other spacecraft in Earth orbit. It would help test the feasibility of in-space inspection and repair. The spacecraft was also designed to test systems that would allow the spacecraft to maneuver autonomously.

USA-165

XSS-11 computer model
Mission type	Technology
Operator	AFRL
COSPAR ID	2005-011A
SATCAT no.	28636
Spacecraft properties
Manufacturer	Lockheed Martin
Launch mass	100 kilograms (220 lb)
Start of mission
Launch date	April 11, 2005 (2005-04-11)
Rocket	Minotaur I
Launch site	Vandenberg SLC-8
Contractor	Orbital
End of mission
Decay date	November 11, 2013 (2013-11-12)[1]
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Eccentricity	0.002487906
Perigee altitude	839 kilometers (521 mi)
Apogee altitude	875 kilometers (544 mi)
Inclination	98.8& degrees
Period	102.1 minutes

USA-165 was built by Lockheed Martin and weighed 125 kg with an excess of 600 m/s delta-v. USA-165 was launched into Low Earth Orbit on April 11, 2005, on a Minotaur rocket and remained in its primary orbit for over eighteen months, but then in December 2006 it was maneuvered into a disposal orbit and lost to satellite spotters. USA-165 was later rediscovered by amateur satellite watcher Kevin Fetter.^[3] The satellite re-entered the atmosphere on November 11, 2013.^[1]

The NASA GRAIL spacecraft design was based on XSS-11 design.